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Sample records for one-way valves reveals

  1. Bronchoscopic treatment of complex persistent air leaks with endobronchial one-way valves.

    PubMed

    Fiorelli, Alfonso; Costanzo, Saveria; Carelli, Emanuele; Di Costanzo, Emilio; Santini, Mario

    2016-04-01

    We reported a case series including 5 patients with persistent air-leaks refractory to standard treatment. All patients were unfit for surgery for the presence of co-morbidities and/or severe respiratory failure due to underlying lung diseases. They were successfully treated with bronchoscopic placement of endobronchial one-way valves. Air-leaks stopped in the first 24 h after the procedure in three patients and 3 and 5 days later, respectively, in the remaining two. No complications were observed and follow-up was uneventful in all patients but one died 25 days after the procedure for systemic sepsis due to peritonis. Patients with important, refractory air leaks having clinical repercussions and unfit for surgery should be early reviewed for bronchoscopic valves treatment.

  2. [Effects of one-way speaking valve placement on swallowing physiology for tracheostomized patients: impact on laryngeal clearance].

    PubMed

    Ohmae, Yukio; Adachi, Zin; Isoda, Yukihide; Maekawa, Hitosi; Kitagawa, Youko; Karaho, Takehiro; Tanabe, Tetuya; Kitahara, Satoshi

    2006-07-01

    Tracheostomy placement affects swallowing function, increasing the risk of aspiration. Recent studies suggest that because of increased risk of swallowing disturbance associated with tracheostomy, one-way speaking valve placement may help to reduce aspiration in tracheostomized patients. We hypothesize that airflow exhaled through the laryngeal cavity using the one-way speaking valve may improve the clearance of residual bolus from the upper airway, thus preventing bolus penetration and aspiration. We studied the effects of one way speaking valve placement on laryngeal clearance and swallowing physiology. Videoendoscopic and videofluoroscopic swallowing were examined in 16 patients with the tracheostomy, and swallowing was compared with and without the one-way speaking valve in place. Valve Valve placement significantly improved laryngeal clearance and the incidence of penetration during swallowing. placement did not, however, significantly affect pharyngeal bolus residue, laryngeal elevation, pharyngeal delay or aspiration. Factors associated with the resumption of oral feedings were sufficient laryngeal elevation during swallow and the prevention of laryngeal penetration and aspiration. We concluded that one-way speaking valve placement improves laryngeal clearance and prevents laryngeal penetration, resulting in better oropharyngeal swallowing physiology and oral feeding.

  3. 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.

  4. [Placement of one-way endobronchial valves to treat severe pulmonary emphysema in an 84-year-old].

    PubMed

    Carron, Kris O M

    2009-01-01

    An 84-year-old man with end-stage emphysema was hospitalised on two occasions because of an episode of severe COPD exacerbation, each time successfully treated in a classical pharmacological manner. Further analysis of a high-resolution CT chest scan revealed very pronounced destruction of the lung parenchyma in the left lower lobe. Moreover, the degree of destruction in the left lung was of a highly heterogeneous nature and fissure analysis revealed a complete left major fissure. After carefully weighing up the costs against the benefits, two one-way valves of different sizes were implanted in the orifices of the left lower lobe using video bronchoscopy. This intervention had a very satisfactory outcome with positive changes in the lung function parameters, imaging studies and quality of life. The inevitable placement in a nursing home could consequently be postponed and, at follow-up one year later, no exacerbation or pneumonia had developed since the intervention.

  5. Use of One-Way Intrabronchial Valves in Air Leak Management After Tube Thoracostomy Drainage.

    PubMed

    Gilbert, Christopher R; Casal, Roberto F; Lee, Hans J; Feller-Kopman, David; Frimpong, Bernice; Dincer, H Erhan; Podgaetz, Eitan; Benzaquen, Sadia; Majid, Adnan; Folch, Erik; Gorden, Jed A; Chenna, Praveen; Chen, Alex; Abouzgheib, Wissam; Sanny Nonyane, Bareng Aletta; Yarmus, Lonny B

    2016-05-01

    A persistent air leak represents significant clinical management problems, potentially affecting morbidity, mortality, and health care costs. In 2008, a unidirectional, intrabronchial valve received humanitarian device exemption for use in managing prolonged air leak after pulmonary resection. Since its introduction, numerous reports exist but no large series describe current utilization or outcomes. Our aim was to report current use of intrabronchial valves for air leaks and review outcome data associated with its utilization. A multicenter, retrospective review of intrabronchial valve utilization from January 2013 to August 2014 was performed at eight centers. Data regarding demographics, valve utilization, and outcomes were analyzed. We identified 112 patients undergoing evaluation for intrabronchial valve placement, with 67% (75 of 112) undergoing valve implantation. Nearly three quarters of patients underwent valve placement for off-label usage (53 of 75). A total of 195 valves were placed in 75 patients (mean 2.6 per patient; range, 1 to 8) with median time to air leak resolution of 16 days (range, 2 to 156). We present the largest, multicenter study of patients undergoing evaluation for intrabronchial valve use for air leak management. Our data suggest the majority of intrabronchial valve placements are occurring for off-label indications. Although the use of intrabronchial valves are a minimally invasive intervention for air leak management, the lack of rigorously designed studies demonstrating efficacy remains concerning. Prospective randomized controlled studies remain warranted. Copyright © 2016 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  6. Verbal communication with the Blom low profile and Passy-Muir one-way tracheotomy tube speaking valves.

    PubMed

    Adam, Stewart I; Srinet, Prateek; Aronberg, Ryan M; Rosenberg, Graeme; Leder, Steven B

    2015-01-01

    To investigate physiologic parameters, voice production abilities, and functional verbal communication ratings of the Blom low profile voice inner cannula and Passy-Muir one-way tracheotomy tube speaking valves. Case series with planned data collection. Large, urban, tertiary care teaching hospital. Referred sample of 30 consecutively enrolled adults requiring a tracheotomy tube and tested with Blom and Passy-Muir valves. Physiologic parameters recorded were oxygen saturation, respiration rate, and heart rate. Voice production abilities included maximum voice intensity in relation to ambient room noise and maximum phonation duration of the vowel/a/. Functional verbal communication was determined from randomized and blinded listener ratings of counting 1-10, saying the days of the week, and reading aloud the sentence, "There is according to legend a boiling pot of gold at one end." There were no significant differences (p>0.05) between the Blom and Passy-Muir valves for the physiologic parameters of oxygen saturation, respiration rate, and heart rate; voice production abilities of both maximum intensity and duration of/a/; and functional verbal communication ratings. Both valves allowed for significantly greater maximum voice intensity over ambient room noise (p<0.001). The Blom low profile voice inner cannula and Passy-Muir one-way speaking valves exhibited equipoise regarding patient physiologic parameters, voice production abilities, and functional verbal communication ratings. Readers will understand the importance of verbal communication for patients who require a tracheotomy tube; will be able to determine the differences between the Blom low profile voice inner cannula and Passy-Muir one-way tracheotomy tube speaking valves; and will be confident in knowing that both the Blom and Passy-Muir one-way tracheotomy tube speaking valves are equivalent regarding physiological functioning and speech production abilities. Copyright © 2015 Elsevier Inc. All rights

  7. Validating the integrity of one-way check valves for the delivery of contrast solution to multiple patients.

    PubMed

    Gretzinger, D T; Cafazzo, J A; Ratner, J; Conly, J M; Easty, A C

    1996-01-01

    The infusion of contrast solution into multiple patients from a single infusion bag is desired in clinics concerned with the high cost of the solution. Using one-way check valves in the infusion line is a protection method to reduce the risk of blood-borne cross-contamination. The suitability of this method is assessed through testing of the operating characteristics of the valves and infusion system and the high back pressure testing of the valves. The results indicate that the use of back-flow valves can ensure the prevention of flow from the patient to the injector. Results also indicate that the use of sprung valves, those which require a significant forward pressure to open them, are more appropriate for this application.

  8. Endobronchial occlusion with one-way endobronchial valves: a novel technique for persistent air leaks in children.

    PubMed

    Toth, Jennifer W; Podany, Abigail B; Reed, Michael F; Rocourt, Dorothy V; Gilbert, Christopher R; Santos, Mary C; Cilley, Robert E; Dillon, Peter W

    2015-01-01

    In children, persistent air leaks can result from pulmonary infection or barotrauma. Management strategies include surgery, prolonged pleural drainage, ventilator manipulation, and extracorporeal membrane oxygenation (ECMO). We report the use of endobronchial valve placement as an effective minimally invasive intervention for persistent air leaks in children. Children with refractory prolonged air leaks were evaluated by a multidisciplinary team (pediatric surgery, interventional pulmonology, pediatric intensive care, and thoracic surgery) for endobronchial valve placement. Flexible bronchoscopy was performed, and air leak location was isolated with balloon occlusion. Retrievable one-way endobronchial valves were placed. Four children (16 months to 16 years) had prolonged air leaks following necrotizing pneumonia (2), lobectomy (1), and pneumatocele (1). Patients had 1-4 valves placed. Average time to air leak resolution was 12 days (range 0-39). Average duration to chest tube removal was 25 days (range 7-39). All four children had complete resolution of air leaks. All were discharged from the hospital. None required additional surgical interventions. Endobronchial valve placement for prolonged air leaks owing to a variety of etiologies was effective in these children for treating air leaks, and their use may result in resolution of fistulae and avoidance of the morbidity of pulmonary surgery. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. The early detection of lung cancer during follow-up of patients undergoing endobronchial one-way valve treatment for emphysema.

    PubMed

    Fiorelli, Alfonso; Costanzo, Saveria; di Costanzo, Emilio; Santini, Mario

    2015-03-01

    We describe the early detection of lung cancer during the follow-up of two emphysematous patients undergoing endobronchial treatment with one-way valves for severe dyspnea. In both cases, the lung function improvement achieved after the valves placement allowed their surgical treatment. In additional to standard follow-up for evaluating the progression of emphysema, such patients should be enrolled in a screening program. It may allow the early detection of lung cancer with the possibility for surgery in accordance with respiratory function of patient.

  10. Combined Bone Marrow-Derived Mesenchymal Stromal Cell Therapy and One-Way Endobronchial Valve Placement in Patients with Pulmonary Emphysema: A Phase I Clinical Trial.

    PubMed

    de Oliveira, Hugo Goulart; Cruz, Fernanda Ferreira; Antunes, Mariana Alves; de Macedo Neto, Amarilio Vieira; Oliveira, Guilherme Augusto; Svartman, Fabio Munhoz; Borgonovo, Tamara; Rebelatto, Carmen Lucia Kuniyoshi; Weiss, Daniel J; Brofman, Paulo Roberto Slud; Morales, Marcelo Marcos; Lapa E Silva, José Roberto; Rocco, Patricia Rieken Macedo

    2017-03-01

    One-way endobronchial valves (EBV) insertion to reduce pulmonary air trapping has been used as therapy for chronic obstructive pulmonary disease (COPD) patients. However, local inflammation may result and can contribute to worsening of clinical status in these patients. We hypothesized that combined EBV insertion and intrabronchial administration of mesenchymal stromal cells (MSCs) would decrease the inflammatory process, thus mitigating EBV complications in severe COPD patients. This initial study sought to investigate the safety of this approach. For this purpose, a phase I, prospective, patient-blinded, randomized, placebo-controlled design was used. Heterogeneous advanced emphysema (Global Initiative for Chronic Lung Disease [GOLD] III or IV) patients randomly received either allogeneic bone marrow-derived MSCs (10(8) cells, EBV+MSC) or 0.9% saline solution (EBV) (n = 5 per group), bronchoscopically, just before insertion of one-way EBVs. Patients were evaluated 1, 7, 30, and 90 days after therapy. All patients completed the study protocol and 90-day follow-up. MSC delivery did not result in acute administration-related toxicity, serious adverse events, or death. No significant between-group differences were observed in overall number of adverse events, frequency of COPD exacerbations, or worsening of disease. Additionally, there were no significant differences in blood tests, lung function, or radiological outcomes. However, quality-of-life indicators were higher in EBV + MSC compared with EBV. EBV + MSC patients presented decreased levels of circulating C-reactive protein at 30 and 90 days, as well as BODE (Body mass index, airway Obstruction, Dyspnea, and Exercise index) and MMRC (Modified Medical Research Council) scores. Thus, combined use of EBV and MSCs appears to be safe in patients with severe COPD, providing a basis for subsequent investigations using MSCs as concomitant therapy. Stem Cells Translational Medicine 2017;6:962-969.

  11. A Biomechanical Study of Hyoid Bone and Laryngeal Movements During Swallowing Comparing the Blom Low Profile Voice Inner Cannula and Passy-Muir One Way Tracheotomy Tube Speaking Valves.

    PubMed

    Srinet, Prateek; Van Daele, Douglas J; Adam, Stewart I; Burrell, Morton I; Aronberg, Ryan; Leder, Steven B

    2015-12-01

    The aim of this prospective, consecutive, cohort study was to investigate the biomechanical effects, if any, of the Blom low profile voice inner cannula and Passy-Muir one-way tracheotomy tube speaking valves on movement of the hyoid bone and larynx during swallowing. Ten adult patients (8 male, 2 female) with an age range of 61-89 years (mean 71 years) participated. Criteria for inclusion were ≥18 years of age, English speaking, and ability to tolerate both changing to a Blom tracheotomy tube and placement of a one-way tracheotomy tube speaking valve with a fully deflated tracheotomy tube cuff. Digitized videofluoroscopic swallow studies were performed at 30 frames/s and with each patient seated upright in the lateral plane. A total of 18 swallows (three each with 5 cc bolus volumes of single contrast barium and puree + barium × 3 conditions) were analyzed for each participant. Variables evaluated included larynx-to-hyoid bone excursion (mm), maximum hyoid bone displacement (mm), and aspiration status under three randomized conditions: 1. Tracheotomy tube open with no inner cannula; 2. Tracheotomy tube with Blom valve; and 3. Tracheotomy tube with Passy-Muir valve. Blinded reliability testing with a Pearson product moment correlation was performed on 20 % of the data. Intra- and inter-rater reliability for combined measurements of larynx-to-hyoid bone excursion and maximum hyoid bone displacement was r = 0.98. Intra- and inter-rater reliability for aspiration status was 100 %. No significant differences (p > 0.05) were found for larynx-to-hyoid bone excursion and maximum hyoid bone displacement during swallowing based upon an open tracheotomy tube, Blom valve, or Passy-Muir valve. Aspiration status was identical for all three randomized conditions. The presence of a one-way tracheotomy tube speaking valve did not significantly alter two important components of normal pharyngeal swallow biomechanics, i.e., hyoid bone and laryngeal movements

  12. 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

  13. 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.

  14. Experimental one-way quantum computing.

    PubMed

    Walther, P; Resch, K J; Rudolph, T; Schenck, E; Weinfurter, H; Vedral, V; Aspelmeyer, M; Zeilinger, A

    2005-03-10

    Standard quantum computation is based on sequences of unitary quantum logic gates that process qubits. The one-way quantum computer proposed by Raussendorf and Briegel is entirely different. It has changed our understanding of the requirements for quantum computation and more generally how we think about quantum physics. This new model requires qubits to be initialized in a highly entangled cluster state. From this point, the quantum computation proceeds by a sequence of single-qubit measurements with classical feedforward of their outcomes. Because of the essential role of measurement, a one-way quantum computer is irreversible. In the one-way quantum computer, the order and choices of measurements determine the algorithm computed. We have experimentally realized four-qubit cluster states encoded into the polarization state of four photons. We characterize the quantum state fully by implementing experimental four-qubit quantum state tomography. Using this cluster state, we demonstrate the feasibility of one-way quantum computing through a universal set of one- and two-qubit operations. Finally, our implementation of Grover's search algorithm demonstrates that one-way quantum computation is ideally suited for such tasks.

  15. 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.

  16. One-way regular electromagnetic mode immune to backscattering.

    PubMed

    Deng, Xiaohua; Hong, Lujun; Zheng, Xiaodong; Shen, Linfang

    2015-05-10

    In this paper, we present a basic model of robust one-way electromagnetic modes at microwave frequencies, which is formed by a semi-infinite gyromagnetic yttrium-iron-garnet with dielectric cladding terminated by a metal plate. It is shown that this system supports not only one-way surface magnetoplasmons (SMPs) but also a one-way regular mode, which is guided by the mechanism of total internal reflection. Like one-way SMPs, the one-way regular mode can be immune to backscattering, and two types of one-way modes together make up a complete dispersion band for the system.

  17. 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

  18. Quantification of Calcified Particles in Human Valve Tissue Reveals Asymmetry of Calcific Aortic Valve Disease Development.

    PubMed

    Yabusaki, Katsumi; Hutcheson, Joshua D; Vyas, Payal; Bertazzo, Sergio; Body, Simon C; Aikawa, Masanori; Aikawa, Elena

    2016-01-01

    Recent studies indicated that small calcified particles observable by scanning electron microscopy (SEM) may initiate calcification in cardiovascular tissues. We hypothesized that if the calcified particles precede gross calcification observed in calcific aortic valve disease (CAVD), they would exhibit a regional asymmetric distribution associated with CAVD development, which always initiates at the base of aortic valve leaflets adjacent to the aortic outflow in a region known as the fibrosa. Testing this hypothesis required counting the calcified particles in histological sections of aortic valve leaflets. SEM images, however, do not provide high contrast between components within images, making the identification and quantification of particles buried within tissue extracellular matrix difficult. We designed a new unique pattern-matching based technique to allow for flexibility in recognizing particles by creating a gap zone in the detection criteria that decreased the influence of non-particle image clutter in determining whether a particle was identified. We developed this flexible pattern particle-labeling (FpPL) technique using synthetic test images and human carotid artery tissue sections. A conventional image particle counting method (preinstalled in ImageJ) did not properly recognize small calcified particles located in noisy images that include complex extracellular matrix structures and other commonly used pattern-matching methods failed to detect the wide variation in size, shape, and brightness exhibited by the particles. Comparative experiments with the ImageJ particle counting method demonstrated that our method detected significantly more (p < 2 × 10(-7)) particles than the conventional method with significantly fewer (p < 0.0003) false positives and false negatives (p < 0.0003). We then applied the FpPL technique to CAVD leaflets and showed a significant increase in detected particles in the fibrosa at the base of the leaflets (p

  19. Quantification of Calcified Particles in Human Valve Tissue Reveals Asymmetry of Calcific Aortic Valve Disease Development

    PubMed Central

    Yabusaki, Katsumi; Hutcheson, Joshua D.; Vyas, Payal; Bertazzo, Sergio; Body, Simon C.; Aikawa, Masanori; Aikawa, Elena

    2016-01-01

    Recent studies indicated that small calcified particles observable by scanning electron microscopy (SEM) may initiate calcification in cardiovascular tissues. We hypothesized that if the calcified particles precede gross calcification observed in calcific aortic valve disease (CAVD), they would exhibit a regional asymmetric distribution associated with CAVD development, which always initiates at the base of aortic valve leaflets adjacent to the aortic outflow in a region known as the fibrosa. Testing this hypothesis required counting the calcified particles in histological sections of aortic valve leaflets. SEM images, however, do not provide high contrast between components within images, making the identification and quantification of particles buried within tissue extracellular matrix difficult. We designed a new unique pattern-matching based technique to allow for flexibility in recognizing particles by creating a gap zone in the detection criteria that decreased the influence of non-particle image clutter in determining whether a particle was identified. We developed this flexible pattern particle-labeling (FpPL) technique using synthetic test images and human carotid artery tissue sections. A conventional image particle counting method (preinstalled in ImageJ) did not properly recognize small calcified particles located in noisy images that include complex extracellular matrix structures and other commonly used pattern-matching methods failed to detect the wide variation in size, shape, and brightness exhibited by the particles. Comparative experiments with the ImageJ particle counting method demonstrated that our method detected significantly more (p < 2 × 10−7) particles than the conventional method with significantly fewer (p < 0.0003) false positives and false negatives (p < 0.0003). We then applied the FpPL technique to CAVD leaflets and showed a significant increase in detected particles in the fibrosa at the base of the leaflets (p

  20. VALVE

    DOEpatents

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

    1962-04-17

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

  1. 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.

  2. Operator structures and quantum one-way LOCC conditions

    NASA Astrophysics Data System (ADS)

    Kribs, David W.; Mintah, Comfort; Nathanson, Michael; Pereira, Rajesh

    2017-09-01

    We conduct the first detailed analysis in quantum information of recently derived operator relations from the study of quantum one-way local operations and classical communications (LOCC). We show how operator structures such as operator systems, operator algebras, and Hilbert C*-modules naturally arise in this setting. We make use of these structures to derive new results and bounds in the study of one-way LOCC, and we use the approach to uncover new derivations of some previously established results.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Efficient quantum circuits for one-way quantum computing.

    PubMed

    Tanamoto, Tetsufumi; Liu, Yu-Xi; Hu, Xuedong; Nori, Franco

    2009-03-13

    While Ising-type interactions are ideal for implementing controlled phase flip gates in one-way quantum computing, natural interactions between solid-state qubits are most often described by either the XY or the Heisenberg models. We show an efficient way of generating cluster states directly using either the imaginary SWAP (iSWAP) gate for the XY model, or the sqrt[SWAP] gate for the Heisenberg model. Our approach thus makes one-way quantum computing more feasible for solid-state devices.

  8. 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

  9. 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.

  10. 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.

  11. One-way quantum computing in the optical frequency comb.

    PubMed

    Menicucci, Nicolas C; Flammia, Steven T; Pfister, Olivier

    2008-09-26

    One-way quantum computing allows any quantum algorithm to be implemented easily using just measurements. The difficult part is creating the universal resource, a cluster state, on which the measurements are made. We propose a scalable method that uses a single, multimode optical parametric oscillator (OPO). The method is very efficient and generates a continuous-variable cluster state, universal for quantum computation, with quantum information encoded in the quadratures of the optical frequency comb of the OPO.

  12. On measuring the one-way speed of light

    NASA Astrophysics Data System (ADS)

    Spavieri, G.

    2012-03-01

    The crucial problem of how to synchronize clocks and measure the one-way speed of light was originally discussed by Poincaré and Einstein. After being neglected for many decades, the Poincaré-Einstein problem of synchronization revived in 1977 with the work of Mansouri and Sexl, by which the one-way speed remains undetermined, allowing for unequal values of the speed of light in opposite directions. We review this problem in the framework of relativistic theories that assume clock-retardation and rod-contraction. We show that, for preferred frame theories, convection or "open" currents yield a magnetic field that depends on the velocity v with respect to the preferred frame S o . We also outline an experiment, based on Faraday's law of induction, that can determine the velocity v, identify S o , and test special relativity versus preferred frame theories. This result resolves the Poincaré-Einstein problem and shows that, in principle, the one-way speed c can be measured.

  13. Successive positive contrast in one-way avoidance learning.

    PubMed

    Cándido, Antonio; Maldonado, Antonio; Rodríguez, Alicia; Morales, Alberto

    2002-04-01

    The main finding of these experiments was a positive contrast effect in one-way avoidance learning. Experiment 1 showed that increasing safety time during one-way avoidance training led to improved performance, surpassing that of a control group that had received the high reward (safe time) from the beginning of training. Experiment 2 showed that a similar positive contrast effect occurred when the time spent in the danger compartment before the onset of the warning signal was shortened. These results suggest that time spent in a safe context acts as a reinforcer of the avoidance response; however, its incentive value depends not only on its duration, but also on the length of the time spent in the danger compartment before the onset of the signal. Overall, results also suggest that the avoidance response is a mixture of flight (motivated by fear) and approach (to a safe place) behaviour. The specific weight of the flight or approach component may be a function of the time and the amount of activation of each emotional state (fear or relief) due to opponent homeostatic compensatory processes that occur in the danger and safe compartments during one-way avoidance learning.

  14. A one-way text messaging intervention for obesity.

    PubMed

    Ahn, Ahleum; Choi, Jaekyung

    2016-04-01

    Worldwide, there has been a startling increase in the number of people who are obese or overweight. Obesity increases the risk of cardiovascular disease and overall mortality. Mobile phone messaging is an important means of human communication globally. Because the mobile phone can be used anywhere at any time, mobile phone messaging has the potential to manage obesity. We investigated the effectiveness of a one-way text messaging intervention for obesity. Participants' body mass index and waist circumference were measured at the beginning of the programme and again after 12 weeks. The text message group received text messages about exercise, dietary intake, and general information about obesity three times a week, while the control group did not receive any text messages from the study. Of the 80 participants, 25 subjects in the text message group and 29 participants in the control group completed the study. After adjusting for baseline body mass index, the body mass index was significantly lower in the text message group than in the control group (27.9 vs. 28.3; p = 0.02). After adjusting for the baseline waist circumference, the difference of waist circumference between the text message group and control group was not significant (93.4 vs. 94.6; p = 0.13). The one-way text messaging intervention was a simple and effective way to manage obesity. The one-way text messaging intervention may be a useful method for lifestyle modification in obese subjects. © The Author(s) 2015.

  15. 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.

  16. Nonreciprocity and one-way topological transitions in hyperbolic metamaterials

    NASA Astrophysics Data System (ADS)

    Leviyev, A.; Stein, B.; Christofi, A.; Galfsky, T.; Krishnamoorthy, H.; Kuskovsky, I. L.; Menon, V.; Khanikaev, A. B.

    2017-07-01

    Control of the electromagnetic waves in nano-scale structured materials is crucial to the development of next generation photonic circuits and devices. In this context, hyperbolic metamaterials, where elliptical isofrequency surfaces are morphed into surfaces with exotic hyperbolic topologies when the structure parameters are tuned, have shown unprecedented control over light propagation and interaction. Here we show that such topological transitions can be even more unusual when the hyperbolic metamaterial is endowed with nonreciprocity. Judicious design of metamaterials with reduced spatial symmetries, together with the breaking of time-reversal symmetry through magnetization, is shown to result in nonreciprocal dispersion and one-way topological phase transitions in hyperbolic metamaterials.

  17. Cutting edge: back to "one-way" germinal centers.

    PubMed

    Meyer-Hermann, Michael E; Maini, Philip K

    2005-03-01

    The present status of germinal center (GC) research is revisited using in silico simulations based on recent lymphocyte motility data in mice. The generally adopted view of several rounds of somatic hypermutations and positive selection is analyzed with special emphasis on the spatial organization of the GC reaction. We claim that the development of dark zones is not necessary for successful GC reactions to develop. We find that a recirculation of positively selected centrocytes to the dark zone is rather unlikely. Instead we propose a scenario that combines a multiple-step mutation and selection concept with a "one-way" GC in the sense of cell migration.

  18. Acoustic one-way open tunnel by using metasurface

    NASA Astrophysics Data System (ADS)

    Zhu, Yi-Fan; Zou, Xin-Ye; Liang, Bin; Cheng, Jian-Chun

    2015-09-01

    We design and experimentally demonstrate an acoustic tunnel completely open for substances like fluids or other energy fluxes to exchange while allowing sound to pass only in one direction. This significant feature is based on a distinctive mechanism using metasurface pairs to yield asymmetric extraordinary reflections along opposite directions. Theoretical analysis is presented to analytically predict the trajectory of the wave. The experimental results agree well with the numerical results and the theoretical predictions. Our design may pave the way to more versatile acoustic one-way devices with potential applications in many scenarios like duct noise control and ultrasonic therapy.

  19. One-way entangled-photon autocompensating quantum cryptography

    NASA Astrophysics Data System (ADS)

    Walton, Zachary D.; Abouraddy, Ayman F.; Sergienko, Alexander V.; Saleh, Bahaa E.; Teich, Malvin C.

    2003-06-01

    A quantum cryptography implementation is presented that uses entanglement to combine one-way operation with an autocompensating feature that has hitherto only been available in implementations that require the signal to make a round trip between the users. Using the concept of advanced waves, it is shown that this proposed implementation is related to the round-trip implementation in the same way that Ekert’s two-particle scheme is related to the original one-particle scheme of Bennett and Brassard. The practical advantages and disadvantages of the proposed implementation are discussed in the context of existing schemes.

  20. One-way visibility using two parallel aerosol clouds.

    PubMed

    Alyones, Sharhabeel; Bruce, Charles W; Granado, Michael; Jelinek, Al V

    2015-01-01

    In this article, we experimentally and theoretically test the range of applicability of a patent that predicts one-way visibility through two successive parallel aerosol clouds, one scattering dominant and the other absorption dominant. A laboratory environment experiment has been designed to determine the ranges of transmissivity and contrast enhancement that might be of interest for military applications. In this study we show that transmissivities in the several percent range and lower are essential for any reasonable contrast enhancement between the two sides of the clouds.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. Acoustic topological insulator and robust one-way sound transport

    NASA Astrophysics Data System (ADS)

    He, Cheng; Ni, Xu; Ge, Hao; Sun, Xiao-Chen; Chen, Yan-Bin; Lu, Ming-Hui; Liu, Xiao-Ping; Chen, Yan-Feng

    2016-12-01

    Topological design of materials enables topological symmetries and facilitates unique backscattering-immune wave transport. In airborne acoustics, however, the intrinsic longitudinal nature of sound polarization makes the use of the conventional spin-orbital interaction mechanism impossible for achieving band inversion. The topological gauge flux is then typically introduced with a moving background in theoretical models. Its practical implementation is a serious challenge, though, due to inherent dynamic instabilities and noise. Here we realize the inversion of acoustic energy bands at a double Dirac cone and provide an experimental demonstration of an acoustic topological insulator. By manipulating the hopping interaction of neighbouring ’atoms’ in this new topological material, we successfully demonstrate the acoustic quantum spin Hall effect, characterized by robust pseudospin-dependent one-way edge sound transport. Our results are promising for the exploration of new routes for experimentally studying topological phenomena and related applications, for example, sound-noise reduction.

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. Dynamics of cold atoms crossing a one-way barrier

    NASA Astrophysics Data System (ADS)

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

    2009-06-01

    We implemented an optical one-way potential barrier that allows ultracold R87b atoms to transmit through when incident on one side of the barrier but reflect from the other. This asymmetric barrier is a realization of Maxwell’s demon, which can be employed to produce phase-space compression and has implications for cooling atoms and molecules not amenable to standard laser-cooling techniques. The barrier comprises two focused Gaussian laser beams that intersect the focus of a far-off-resonant single-beam optical dipole trap that holds the atoms. The main barrier beam presents a state-dependent potential to incident atoms, while the repumping barrier beam optically pumps atoms to a trapped state. We investigated the robustness of the barrier asymmetry to changes in the barrier-beam separation, the initial atomic potential energy, the intensity of the second beam, and the detuning of the first beam. We performed simulations of the atomic dynamics in the presence of the barrier, showing that the initial three-dimensional momentum distribution plays a significant role, and that light-assisted collisions are likely the dominant loss mechanism. We also carefully examined the relationship to Maxwell’s demon and explicitly accounted for the apparent decrease in entropy for our particular system.

  12. Virulence conversion of Legionella pneumophila: a one-way phenomenon.

    PubMed Central

    Catrenich, C E; Johnson, W

    1988-01-01

    Previous investigations have shown that Legionella pneumophila converts from virulence to avirulence after passage on supplemented Mueller-Hinton (SMH) agar and may convert back to virulence after passage in guinea pigs. However, there is no additional information concerning the apparent interconversion of virulent and avirulent derivatives of L. pneumophila cultures. We investigated the stability of a parental virulent culture and its avirulent derivatives and the growth and viability of these cultures on charcoal-yeast extract (CYE) and SMH agars. Avirulent derivatives of a highly virulent L. pneumophila culture were obtained by passage of the virulent parent culture on SMH agar. The only time a virulent L. pneumophila culture was recoverable from an avirulent culture was when the avirulent culture was derived from a saline suspension of a virulent culture which had been passaged only five times on SMH agar. When an avirulent culture was derived from a virulent culture passaged 25 times on SMH agar or from an isolated colony which grew on a SMH agar plate, we were unable to recover a virulent culture after successive passage through guinea pigs. These results suggest that the conversion process which occurs between virulent and avirulent forms of L. pneumophila is a one-way phenomenon from virulence to avirulence and that stable avirulent derivatives can be isolated. Furthermore, our findings suggest that SMH agar acts as a selective medium for the growth of avirulent L. pneumophila, and growth on SMH agar may be a phenotypic marker for avirulence. Virulent cells, although unable to grow on SMH agar, may remain viable for several passages on SMH agar and propagate when inoculated into guinea pigs. Images PMID:3182073

  13. The Laguerre finite difference one-way equation solver

    NASA Astrophysics Data System (ADS)

    Terekhov, Andrew V.

    2017-05-01

    This paper presents a new finite difference algorithm for solving the 2D one-way wave equation with a preliminary approximation of a pseudo-differential operator by a system of partial differential equations. As opposed to the existing approaches, the integral Laguerre transform instead of Fourier transform is used. After carrying out the approximation of spatial variables it is possible to obtain systems of linear algebraic equations with better computing properties and to reduce computer costs for their solution. High accuracy of calculations is attained at the expense of employing finite difference approximations of higher accuracy order that are based on the dispersion-relationship-preserving method and the Richardson extrapolation in the downward continuation direction. The numerical experiments have verified that as compared to the spectral difference method based on Fourier transform, the new algorithm allows one to calculate wave fields with a higher degree of accuracy and a lower level of numerical noise and artifacts including those for non-smooth velocity models. In the context of solving the geophysical problem the post-stack migration for velocity models of the types Syncline and Sigsbee2A has been carried out. It is shown that the images obtained contain lesser noise and are considerably better focused as compared to those obtained by the known Fourier Finite Difference and Phase-Shift Plus Interpolation methods. There is an opinion that purely finite difference approaches do not allow carrying out the seismic migration procedure with sufficient accuracy, however the results obtained disprove this statement. For the supercomputer implementation it is proposed to use the parallel dichotomy algorithm when solving systems of linear algebraic equations with block-tridiagonal matrices.

  14. A new periodogram using one-way analysis of variance for circadian rhythms.

    PubMed

    Shono, M; Shono, H; Ito, Y; Muro, M; Maeda, Y; Sugimori, H

    2000-06-01

    A new periodogram was proposed using one-way analysis of variance (ANOVA), termed ANOVA periodogram, in order to reveal a precise significant periodicity. Thirty 3-day complex computer-simulated time series with known periodicity (24 h) and three 2-h data-missing occurring periodically (23 h, 20 min) were used to compare the ANOVA periodogram with Enright's one. In results, the ANOVA periodogram was superior to Enright's periodogram in the accuracy of assessing the major periodicity.

  15. 21 CFR 868.5870 - Nonrebreathing valve.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...) Identification. A nonrebreathing valve is a one-way valve that directs breathing gas flow to the patient and vents exhaled gases into the atmosphere. (b) Classification. Class II (performance standards)....

  16. One-way light transport controlled by synthetic magnetic fluxes and {\\mathscr{P}}{\\mathscr{T}}-symmetric resonators

    NASA Astrophysics Data System (ADS)

    Jin, L.; Wang, P.; Song, Z.

    2017-01-01

    Controlled directional light propagation using optical nonlinearity has previously been proposed. Here, we propose a one-way optical device with linear elements controlled by synthetic magnetic fluxes. The device consists of two parity–time symmetric side-coupled resonators with balanced gain and loss. The gain and loss break the reflection symmetry and the magnetic fluxes break the transmission symmetry. Through tuning the magnetic fluxes, reflectionless full transmission in one direction and transmissionless full reflection in the opposite direction can be achieved. The device acts as a light-checking valve, preventing wave propagation in one direction. The proposed one-way transporter uses the nonreciprocity induced by non-Hermiticity and magnetic fluxes without applying nonlinearity. We anticipate that our findings will be useful for optical control and manipulation.

  17. 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.

  18. 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 allocated...

  19. 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.

  20. 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.

  1. 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.…

  2. 47 CFR 90.490 - One-way paging operations in the private services.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... directly from telephone positions in the public switched telephone network. When land stations are multiple... 47 Telecommunication 5 2012-10-01 2012-10-01 false One-way paging operations in the private... SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES Paging Operations § 90.490 One-way...

  3. 47 CFR 90.490 - One-way paging operations in the private services.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... directly from telephone positions in the public switched telephone network. When land stations are multiple... 47 Telecommunication 5 2014-10-01 2014-10-01 false One-way paging operations in the private... SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES Paging Operations § 90.490 One-way...

  4. 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…

  5. 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…

  6. Nonlinear behavior analysis of spur gear pairs with a one-way clutch

    NASA Astrophysics Data System (ADS)

    Gill-Jeong, Cheon

    2007-04-01

    Nonlinear behavior analysis of a paired spur gear system with a one-way clutch was used to verify whether a one-way clutch is effective for reducing torsional vibration. The dynamic responses were studied over a wide frequency range by speed sweeping to check the nonlinear behavior using numerical integration. The gear system with a one-way clutch showed typical nonlinear behavior, such as softening nonlinearity and jump phenomena. The oscillating component of the dynamic transmission error was reduced over the entire frequency range compared to a system without a one-way clutch, and double-side contact could be prevented, even with very small backlash. Installing a one-way clutch on both sides of the gear system was more effective at mitigating the negative effects of various parameter changes than installing one only on the input or output side.

  7. Evidence of one-way flow bioaccumulation of gold nanoparticles across two trophic levels

    NASA Astrophysics Data System (ADS)

    Larguinho, Miguel; Correia, Daniela; Diniz, Mário S.; Baptista, Pedro V.

    2014-08-01

    This work reports a one-way flow bioaccumulation of gold nanoparticles (AuNPs) in aquatic organisms between two trophic levels. First, Dunaliella salina cells were exposed to citrate-capped AuNPs at different concentrations and during distinct exposure periods to assess internalization and behavior. Afterward, D. salina was incubated with both citrate-capped and functionalized (PEGylated) AuNPs for 24 h and later fed to Mytilus galloprovincialis. Analysis was carried out to assess Au content, histological differences and oxidative stress. These algae were fed to the model organism M. galloprovincialis (Mediterranean mussel) as it is considered of major importance for assessing toxic effects and bioaccumulation of different pollutants in aquatic environments. Elemental Au analysis revealed an uptake of about 76 % of the initial amount of AuNPs (and 36 % for PEGylated AuNPs) in microalgae. Mussel gills and digestive gland showed variable Au content in individuals fed with D. salina previously exposed to AuNPs. No significant morphological alterations were observed in D. salina or mussel digestive glands. Glutathione-s-transferase activity and total antioxidant capacity were assessed as oxidative stress biomarkers showing that AuNPs are not prone to trigger the induction of defenses against oxidative stress.

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

    PubMed Central

    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.

    2016-01-01

    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 are sufficient to retain SOS on the membrane for many minutes, during which a single SOS molecule can processively activate thousands of Ras molecules. These observations raise questions concerning how receptors maintain control of SOS in cells and how membrane-recruited SOS is ultimately released. We addressed these questions in quantitative reconstituted SOS-deficient chicken B cell signaling systems combined with single molecule measurements in supported membranes. These studies reveal an essentially one-way trafficking process in which membrane-recruited SOS remains trapped on the membrane and continuously activates Ras until it is actively removed via endocytosis. PMID:27501536

  9. One-way ViSP (Visually Servoed Paired structured light system) for structural displacement monitoring

    NASA Astrophysics Data System (ADS)

    Jeon, H.; Kim, Y. J.; Myeong, W.; Myung, H.

    2017-08-01

    Nowadays, the evaluation of structural safety and serviceability is becoming more essential due to the deterioration of civil infrastructures. In particular, the structural displacement which provides important information on structural conditions is considered one of the important indicators for the health monitoring of structures. To estimate the structural displacement, this paper proposes a one-way projection-type six degree-of-freedom (DOF) displacement measurement system based on vision and laser sensors, named one-way ViSP (Visually Servoed Paired structured light system). The system is composed of a transmitter and a receiver, which are facing to each other. The transmitter consists of a 1D laser range finder, two lasers, and a 2-DOF manipulator, while the receiver consists of a screen and a camera. The one-way ViSP estimates relative displacements between a transmitter and receiver by measuring the coordinates of three projected beam spots and a distance. Besides the advantages such as high accuracy in 6-DOF displacement measurement, low cost, and real-time monitoring possibilities, the one-way ViSP can cover large areas such as dams and inclined planes by using multiple receivers. Through various simulations and experiments, it is shown that the one-way ViSP has high accuracy in 6-DOF displacement estimation.

  10. Heimlich valve and pneumothorax

    PubMed Central

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

    2015-01-01

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

  11. 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.

  12. One-way quantum deficit and quantum coherence in the anisotropic XY chain

    NASA Astrophysics Data System (ADS)

    Ye, Biao-Liang; Li, Bo; Zhao, Li-Jun; Zhang, Hai-Jun; Fei, Shao-Ming

    2017-03-01

    In this study, we investigate pairwise non-classical correlations measured using a one-way quantum deficit as well as quantum coherence in the XY spin-1/2 chain in a transverse magnetic field for both zero and finite temperatures. The analytical and numerical results of our investigations are presented. In the case when the temperature is zero, it is shown that the one-way quantum deficit can characterize quantum phase transitions as well as quantum coherence. We find that these measures have a clear critical point at λ = 1. When λ ≤ 1, the one-way quantum deficit has an analytical expression that coincides with the relative entropy of coherence. We also study an XX model and an Ising chain at the finite temperatures.

  13. One-way steering of optical fields via dissipation of an atomic reservoir

    NASA Astrophysics Data System (ADS)

    Rao, Shi; Hu, Xiangming; Li, Lingchao; Xu, Jun

    2016-11-01

    Einstein-Podolsky-Rosen (EPR) steering as a form of quantum correlation lies between entanglement and Bell nonlocality and exhibits an inherent asymmetry between two observers. We study EPR steering of two fields, which are generated via four-wave mixing processes and are entangled with each other due to the dissipation of the atomic reservoir. It is shown that the one-way steering happens from one mode to the other for different cavity decay rates and not too small cooperation parameters. Depending on the adiabatic and nonadiabatic conditions, the one-way steering occurs in a different detuning region when the cooperation parameters are relatively small. An increase in the cooperation parameters leads to an increase both in the parameter region and in the degree for the one-way steering. Finally we generalize the present scheme to the cases of the bright and/or collective fields.

  14. Quantum de Finetti Theorem under Fully-One-Way Adaptive Measurements.

    PubMed

    Li, Ke; Smith, Graeme

    2015-04-24

    We prove a version of the quantum de Finetti theorem: permutation-invariant quantum states are well approximated as a probabilistic mixture of multifold product states. The approximation is measured by distinguishability under measurements that are implementable by fully-one-way local operations and classical communication (LOCC). Our result strengthens Brandão and Harrow's de Finetti theorem where a kind of partially-one-way LOCC measurements was used for measuring the approximation, with essentially the same error bound. As main applications, we show (i) a quasipolynomial-time algorithm which detects multipartite entanglement with an amount larger than an arbitrarily small constant (measured with a variant of the relative entropy of entanglement), and (ii) a proof that in quantum Merlin-Arthur proof systems, polynomially many provers are not more powerful than a single prover when the verifier is restricted to one-way LOCC operations.

  15. Quantum de Finetti Theorem under Fully-One-Way Adaptive Measurements

    NASA Astrophysics Data System (ADS)

    Li, Ke; Smith, Graeme

    2015-04-01

    We prove a version of the quantum de Finetti theorem: permutation-invariant quantum states are well approximated as a probabilistic mixture of multifold product states. The approximation is measured by distinguishability under measurements that are implementable by fully-one-way local operations and classical communication (LOCC). Our result strengthens Brandão and Harrow's de Finetti theorem where a kind of partially-one-way LOCC measurements was used for measuring the approximation, with essentially the same error bound. As main applications, we show (i) a quasipolynomial-time algorithm which detects multipartite entanglement with an amount larger than an arbitrarily small constant (measured with a variant of the relative entropy of entanglement), and (ii) a proof that in quantum Merlin-Arthur proof systems, polynomially many provers are not more powerful than a single prover when the verifier is restricted to one-way LOCC operations.

  16. Identification and calibration of one-way delays in satellite laser ranging systems

    NASA Astrophysics Data System (ADS)

    Prochazka, Ivan; Kodet, Jan; Blazej, Josef; Kirchner, Georg; Koidl, Franz; Wang, Peiyuan

    2017-05-01

    We are reporting on identification and calibration of one-way delays in satellite laser ranging systems. Satellite Laser Ranging (SLR) is a standard technique to measure the distance of satellites as a function of time with millimeter precision and a few millimeters accuracy. For one-way laser ranging, laser time transfer ground to space and for bi- and multi-static laser ranging to space objects identification and measurement of system delays related separately to transmitting and receiving parts of the system are needed. The epochs of transmission and reception of optical signals have to be referred to the coordinated time scale with the accuracy reaching one nanosecond level or better for one-way ranging and space debris multi-static ranging. For transponder ranging and laser time transfer an even higher accuracy of 50 ps or better is needed. These accuracy requirements are by several orders of magnitude higher in comparison to standard SLR applications. A new procedure of calibration of one-way delays related to the SLR systems has been developed and tested. The necessary hardware components needed for calibration measurements were designed and developed in a form of a Calibration Device. It consists of a photon counting detector, an epoch timing device and a dedicated signal cable. The signal propagation delays of these components were determined with an accuracy of better than 20 ps. The signal propagation delay stability of the Calibration Device is on a level of units of picoseconds over days of operation. The Calibration Device and calibration procedure were tested in real measurements at the SLR site in Graz, Austria. The time needed to complete a calibration of one-way delays of the SLR system is less than two days. The one-way system delays were determined with the accuracy better than 50 ps. The measurement principle, Calibration Device and the first results are presented.

  17. 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.

  18. Gaussian two-mode attacks in one-way quantum cryptography

    NASA Astrophysics Data System (ADS)

    Ottaviani, Carlo; Mancini, Stefano; Pirandola, Stefano

    2017-05-01

    We investigate the asymptotic security of one-way continuous variable quantum key distribution against Gaussian two-mode coherent attacks. The one-way protocol is implemented by arranging the channel uses in two-mode blocks. By applying symmetric random permutations over these blocks, the security analysis is in fact reduced to study two-mode coherent attacks and, in particular, Gaussian ones, due to the extremality of Gaussian states. We explicitly show that the use of two-mode Gaussian correlations by an eavesdropper leads to asymptotic secret key rates which are strictly larger than the rate obtained under standard single-mode Gaussian attacks.

  19. Test and Analysis of Upgraded One-Way Reinforced Concrete Floor Slabs.

    DTIC Science & Technology

    1981-07-01

    be needed to protect these key people, as well as others that stay in high-risk areas, from the effects of nuclear weapons. As stated before, the...most of the load is carried in the short direction and one-way action is obtained in effect (References 11-13). Still another kind is the one-way...though, due to the excessive amount of work to assemble them, the amount of room they take up, and the obstruction of passages. The effectiveness of

  20. 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.

  1. 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…

  2. 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…

  3. 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

  4. [Molecular basis of one-way serological reaction between SINV and XJ-160 virus].

    PubMed

    Wang, Li-hua; Fu, Shi-hong; Yang, Yi-liang; Zhu, Wu-yang; Tang, Qing; Liang, Guo-dong

    2010-05-01

    The purpose of this study is to elucidate the molecular mechanism of one-way serological reaction between XJ-160 virus and SINV by recombinant viruses which exchanged the glycoprotein genes individually or simultaneously. Three recombinant viruses were obtained based on the whole-length infectious cDNA clone of XJ-160 virus. The infectivity and pathogenesis to BHK-21 cells and animals were studied and the gene which controlled this one-way serological reaction phenomenon was searched by MCPENT. The results showed that the E2 glycoprotein was the main factor which influenced the growth rate, plaque morphology and pathogenicity of BHK-21 cells and suckling mice. The results of MCPENT showed that the E2 glycoprotein of SINV played a major role in this one-way serological reaction phenomenon. Our study identified the SINE2 gene was the determined gene for one way serological reaction between XJ-160 virus and SINV, and this research laid the foundation for further analysis of the genomic structure and function of SINV.

  5. 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…

  6. Big sagebrush response to one-way and two-way chaining in Southeastern Utah

    Treesearch

    John A. Fairchild; James N. Davis; Jack D. Brotherson

    2005-01-01

    A decadent, mixed stand of Wyoming big sagebrush, Artemisia tridentata wyomingensis, and mountain big sagebrush, Artemisia tridentata vaseyana, located north of Cisco, Utah, was subjected to one-way and two-way chaining treatments in November 1987. The effect of the treatments on plant community characteristics and shrub vigor was...

  7. More Than One Way to Catch a Fish: Effective Translation of Ocean Science for the Public

    DTIC Science & Technology

    2006-09-01

    translation is one way to make science and technical information more accessible to the public and thereby, improve scientific literacy of many Americans...We present three information translation models that promote scientific and technical literacy . I. INTRODUCTION As more Americans live... literacy ). The organizational structure of the Operations and Education groups (Figure 1) highlights how the two groups interact to provide

  8. Transmission mechanism with parallel transmission systems including one way clutches, one being lockable

    SciTech Connect

    Akashi, T.; Ito, H.; Yamada, S.

    1986-03-18

    A transmission mechanism is described which consists of: an input shaft; an output shaft; a first on-off clutch; a second on-off clutch; a first one way clutch; a second one way clutch; a first gear train having a first reduction gear ratio; a second gear train having a second reduction gear ratio smaller than the first reduction gear ratio; a third gear train having a third reduction gear ratio smaller than the second reduction gear ratio; a fourth gear train having a fourth gear reduction gear ratio smaller than the third reduction gear ratio; a first synchronizer which connects the input shaft and the output shaft; and a second synchronizer which connects the input shaft and the output shaft via a series connection of the second on-off clutch, the second one way clutch, and the second gear train when the second synchronizer is shifted to a first side of a neutral position thereof so as to transmit rotational power from the input shaft to the output shaft in the normal rotational direction and which connects the input shaft and the output shaft via a series connection of the second on-off clutch, the second one way clutch, and the fourth gear train when the second synchronizer is shifted to a second side of the neutral position of the second synchronizer so as to transmit rotational power from the input shaft to the output shaft in the normal rotational direction.

  9. 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…

  10. 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…

  11. 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.

  12. Quantum one-way permutation over the finite field of two elements

    NASA Astrophysics Data System (ADS)

    de Castro, Alexandre

    2017-06-01

    In quantum cryptography, a one-way permutation is a bounded unitary operator U:{H} → {H} on a Hilbert space {H} that is easy to compute on every input, but hard to invert given the image of a random input. Levin (Probl Inf Transm 39(1):92-103, 2003) has conjectured that the unitary transformation g(a,x)=(a,f(x)+ax), where f is any length-preserving function and a,x \\in {GF}_{{2}^{\\Vert x\\Vert }}, is an information-theoretically secure operator within a polynomial factor. Here, we show that Levin's one-way permutation is provably secure because its output values are four maximally entangled two-qubit states, and whose probability of factoring them approaches zero faster than the multiplicative inverse of any positive polynomial poly( x) over the Boolean ring of all subsets of x. Our results demonstrate through well-known theorems that existence of classical one-way functions implies existence of a universal quantum one-way permutation that cannot be inverted in subexponential time in the worst case.

  13. 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…

  14. 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…

  15. A wind-powered one-way bistable medium with parity effects.

    PubMed

    Rosenberger, Tessa; Schattgen, Graham; King-Smith, Matthew; Shrestha, Prakrit; Maxted, Katsuo J; Lindner, John F

    2017-02-01

    We describe the design, construction, and dynamics of low-cost mechanical arrays of 3D-printed bistable elements whose shapes interact with wind to couple them one-way. Unlike earlier hydromechanical unidirectional arrays, our aeromechanical one-way arrays are simpler, easier to study, and exhibit a broader range of phenomena. Solitary waves or solitons propagate in one direction at speeds proportional to wind speeds. Periodic boundaries enable solitons to annihilate in pairs in arrays with an even number of elements. Solitons propagate indefinitely in odd arrays that frustrate pairing. Large noise spontaneously creates soliton-antisoliton pairs. Soliton annihilation times increase quadratically with initial separations, as expected for random-walk models of soliton collisions.

  16. 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.

  17. 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.

  18. A wind-powered one-way bistable medium with parity effects

    NASA Astrophysics Data System (ADS)

    Rosenberger, Tessa; Schattgen, Graham; King-Smith, Matthew; Shrestha, Prakrit; Maxted, Katsuo J.; Lindner, John F.

    2017-02-01

    We describe the design, construction, and dynamics of low-cost mechanical arrays of 3D-printed bistable elements whose shapes interact with wind to couple them one-way. Unlike earlier hydromechanical unidirectional arrays, our aeromechanical one-way arrays are simpler, easier to study, and exhibit a broader range of phenomena. Solitary waves or solitons propagate in one direction at speeds proportional to wind speeds. Periodic boundaries enable solitons to annihilate in pairs in arrays with an even number of elements. Solitons propagate indefinitely in odd arrays that frustrate pairing. Large noise spontaneously creates soliton-antisoliton pairs. Soliton annihilation times increase quadratically with initial separations, as expected for random-walk models of soliton collisions.

  19. One-way optical transmission in silicon photonic crystal heterojunction with circular and square scatterers

    NASA Astrophysics Data System (ADS)

    Liu, Dan; Hu, Sen; Gao, Yihua

    2017-07-01

    A 2D orthogonal square-lattice photonic crystal (PC) heterojunction consisting of circular and square air holes in silicon is presented. Band structures are calculated using the plane wave expansion method, and the transmission properties are investigated by the finite-different time-domain simulations. Thanks to the higher diffraction orders excited when the circular and square holes are interlaced along the interface, one-way transmission phenomena can exist within wide frequency regions. The higher order diffraction is further enhanced through two different interface optimization designs proposed by modifying the PC structure of the hetero-interface. An orthogonal PC heterojunction for wide-band and efficient one-way transmission is constructed, and the maximum transmissivity is up to 78%.

  20. A comparison of one-way video and two-way video educational videoteleconferencing

    NASA Astrophysics Data System (ADS)

    Hendrix, Craig L.

    1995-05-01

    The literature reviewed in this study supported the effectiveness of educational videoteleconferencing; however, relatively little research was found comparing the two most interactive types of educational videoteleconferencing systems. An experimental research project was conducted, attempting to determine which educational videoteleconferencing system is more effective. Specifically, this project was designed to answer the following question: Is live two-way video with two-way audio more effective than live one-way video with two-way audio educational videoteleconferencing (EVC)?

  1. Non-Black-Box Simulation from One-Way Functions and Applications to Resettable Security

    DTIC Science & Technology

    2012-11-05

    arguments for NP based on the existence of one-way permutations and trapdoor permutations. 6.1 Acknowledgements We are very grateful to Ran Canetti for...technique. In FOCS, 2012. [CGGM00] Ran Canetti , Oded Goldreich, Shafi Goldwasser, and Silvio Micali. Resettable zero- knowledge (extended abstract). In STOC...00, pages 235–244, 2000. [CGH04] Ran Canetti , Oded Goldreich, and Shai Halevi. On the random-oracle methodology as applied to length-restricted

  2. 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

  3. Experimental realization of Deutsch's algorithm in a one-way quantum computer.

    PubMed

    Tame, M S; Prevedel, R; Paternostro, M; Böhi, P; Kim, M S; Zeilinger, A

    2007-04-06

    We report the first experimental demonstration of an all-optical one-way implementation of Deutsch's quantum algorithm on a four-qubit cluster state. All the possible configurations of a balanced or constant function acting on a two-qubit register are realized within the measurement-based model for quantum computation. The experimental results are in excellent agreement with the theoretical model, therefore demonstrating the successful performance of the algorithm.

  4. 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.

  5. 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.

  6. Measurement of one-way velocity of light and light-year

    NASA Astrophysics Data System (ADS)

    Chen, Shao-Guang

    For space science and astronomy the fundamentality of one-way velocity of light (OWVL) is selfevident. The measurement of OWVL (distance / interval) and the clock synchronization with light-signal transfer make a logical circulation. This means that OWVL could not be directly measured but only come indirectly from astronomical method (Romer's Io eclipse and Bradley's sidereal aberration). Furthermore, the light-year by definitional OWVL and the trigonometry distance with AU are also un-measurable. In this report two methods of clock synchronization to solve this problem were proposed: The arriving-time difference of longitudinal-transverse wave (Ts - Tp) or ordinary-extraordinary light (Te - To) is measured by single clock at one end of a dual-speed transmission-line, the signal transmission-delay (from sending-end time Tx to receiving-end time Tp or To) calculated with wave-speed ratio is: (Tp -Tx) = (Ts -Tp) / ((Vp / Vs) - 1) or: (To -Tx) = (Te - To) / ((Vo / Ve ) - 1), where (Vp / Vs) = (E / k) 1/2 is Yang's / shear elastic-modulus ratio obtained by comparing two strains at same stress, (Vo / Ve) = (ne / no) is extraordinary/ordinary light refractive-index ratio obtained by comparing two deflection-angles. Then, two clocks at transmission-line two ends can be synchronized directly to measure the one-way velocity of light and light-year, which work as one earthquakestation with single clock measures first-shake-time and the distance to epicenter. The readings Na and Nb of two counters Ca and Cb with distance L are transferred into a computer C by two leads with transmission-delay Tac and Tbc respectively. The computer progressing subtraction operation exports steady value: (Nb - Na) = f (Ta - Tb ) + f (Tac - Tbc ), where f is the frequency of light-wave always passing Ca and Cb, Ta and Tb are the count-start time of Ca and Cb respectively. From the transmission-delay possess the spatial translational and rotational invariability, the computer exports steady value

  7. Rapid publication-ready MS-Word tables for one-way ANOVA.

    PubMed

    Assaad, Houssein I; Zhou, Lan; Carroll, Raymond J; Wu, Guoyao

    2014-01-01

    Statistical tables are an important component of data analysis and reports in biological sciences. However, the traditional manual processes for computation and presentation of statistically significant results using a letter-based algorithm are tedious and prone to errors. Based on the R language, we present two web-based software for individual and summary data, freely available online, at http://shiny.stat.tamu.edu:3838/hassaad/Table_report1/ and http://shiny.stat.tamu.edu:3838/hassaad/SumAOV1/, respectively. The software are capable of rapidly generating publication-ready tables containing one-way analysis of variance (ANOVA) results. No download is required. Additionally, the software can perform multiple comparisons of means using the Duncan, Student-Newman-Keuls, Tukey Kramer, and Fisher's least significant difference (LSD) tests. If the LSD test is selected, multiple methods (e.g., Bonferroni and Holm) are available for adjusting p-values. Using the software, the procedures of ANOVA can be completed within seconds using a web-browser, preferably Mozilla Firefox or Google Chrome, and a few mouse clicks. Furthermore, the software can handle one-way ANOVA for summary data (i.e. sample size, mean, and SD or SEM per treatment group) with post-hoc multiple comparisons among treatment means. To our awareness, none of the currently available commercial (e.g., SPSS and SAS) or open-source software (e.g., R and Python) can perform such a rapid task without advanced knowledge of the corresponding programming language. Our new and user-friendly software to perform statistical analysis and generate publication-ready MS-Word tables for one-way ANOVA are expected to facilitate research in agriculture, biomedicine, and other fields of life sciences.

  8. Generating equally weighted test particles from the one-way flux of a drifting Maxwellian

    NASA Astrophysics Data System (ADS)

    Makkonen, T.; Airila, M. I.; Kurki-Suonio, T.

    2015-01-01

    The problem of generating equally weighted test particles from the one way flux of drifting Maxwellian is tackled. This paper extends previous work on the subject by presenting a simple and efficient rejection sampling algorithm together with C++ source files. The properties of the underlying probability distribution function, having the form of a normal distribution times x with positive support, are also disseminated. The method presented in this paper has been successfully used to combine fluid and kinetic models for trace impurity problems in plasma physics.

  9. A constructive formulation of the one-way speed of light

    NASA Astrophysics Data System (ADS)

    Iyer, Chandru; Prabhu, G. M.

    2010-02-01

    A formulation of the one-way speed of light in three-dimensional Euclidean space is derived by a constructive approach. This formulation is consistent with the result of the Michelson-Morley experiment in that the harmonic mean of the outward and return speeds is equal to c, the standard value for the speed of electromagnetic radiation in vacuum. It is also shown that a shift in synchronization, proportional to the distance along the line of motion, renders this speed a constant along all directions.

  10. Interferometry with Phase Conjugate Mirrors and Measure of One-Way Velocity of Light

    NASA Astrophysics Data System (ADS)

    Garuccio, Augusto

    2004-12-01

    A Michelson interferometer with a phase-conjugate mirror (PCM) is described and discussed. The behavior of phase conjugate mirrors is discussed and the result of an experiment with a Michelson interferometer with a phase-conjugate mirror is described and commented. This interferometer has been proposed to be used to test the intrinsic non-locality of quantum mechanics. In this paper a new experimental setup to study the one-way velocity of light is proposed, which uses this new interesting device.

  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. 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.

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

    NASA Astrophysics Data System (ADS)

    Gu, Zhong-ming; Liang, Bin; Zou, Xin-ye; Yang, Jing; Li, Yong; Yang, Jun; Cheng, Jian-chun

    2015-11-01

    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.

  14. 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.

  15. 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.

  16. Exact Markov chain and approximate diffusion solution for haploid genetic drift with one-way mutation.

    PubMed

    Hössjer, Ola; Tyvand, Peder A; Miloh, Touvia

    2016-02-01

    The classical Kimura solution of the diffusion equation is investigated for a haploid random mating (Wright-Fisher) model, with one-way mutations and initial-value specified by the founder population. The validity of the transient diffusion solution is checked by exact Markov chain computations, using a Jordan decomposition of the transition matrix. The conclusion is that the one-way diffusion model mostly works well, although the rate of convergence depends on the initial allele frequency and the mutation rate. The diffusion approximation is poor for mutation rates so low that the non-fixation boundary is regular. When this happens we perturb the diffusion solution around the non-fixation boundary and obtain a more accurate approximation that takes quasi-fixation of the mutant allele into account. The main application is to quantify how fast a specific genetic variant of the infinite alleles model is lost. We also discuss extensions of the quasi-fixation approach to other models with small mutation rates.

  17. One-way absorber for linearly polarized electromagnetic wave utilizing composite metamaterial.

    PubMed

    Zhao, Junming; Sun, Liang; Zhu, Bo; Feng, Yijun

    2015-02-23

    This paper presents the proposal and practical design of a one-way absorber for selective linearly polarized electromagnetic (EM) wave. The EM wave polarization rotation property has been combined with polarization selective absorption utilizing a composite metamaterial slab. The energy of certain linearly polarized EM wave can be absorbed along one particular incident direction, but will be fully transmitted through the opposite direction. For the cross polarized wave, the direction dependent propagation properties are totally reversed. A prototype designed with a total slab thickness of only one-sixth of the operating wavelength is verified through both full-wave simulation and experimental measurement in the microwave regime. It achieves absorption efficiency over 83% along one direction, while transmission efficiency over 83% along the opposite direction for one particular linearly polarized wave. The proposed one-way absorber can be applied in EM devices achieving asymmetric transmission for linearly polarized wave or polarization control. The composite metamaterial that combines different functionalities into one design may provide more potential in metamaterial designs for various applications.

  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.

  19. Locomotor activity and one-way active avoidance after intrahippocampal injection of neurotransmitter antagonists.

    PubMed

    Brito, L S; Brito, G N

    1990-01-01

    Sixty-three rats with previous training in a T-maze, bilaterally implanted with cannulae directed toward the dorsal hippocampus, were used in this study. All rats received bilateral 1-microliter injections 20 min before testing for locomotor activity (day 1) and one-way active avoidance (day 3). The following drugs were injected into groups of 4 to 8 animals: scopolamine (9 or 18 micrograms/microliters), propranolol (5 or 10 micrograms/microliters), cimetidine (0.75 or 1.5 micrograms/microliters), sulpiride (5 or 10 micrograms/microliters), or vehicle (Krebs-Ringer). Locomotor activity was not changed by injection of any drug. However, intrahippocampal injections of scopolamine (9 micrograms/microliters) and sulpiride (10 micrograms/microliters) impaired avoidance behavior, particularly during the last five trials of the task. We conclude that muscarinic-cholinergic and D2-dopaminergic, but not beta-adrenergic or H2-histaminergic, mechanisms in the hippocampus are involved in the performance of one-way active avoidance behavior.

  20. Extending the CLAST sequential rule to one-way ANOVA under group sampling.

    PubMed

    Ximénez, Carmen; Revuelta, Javier

    2007-02-01

    Several studies have demonstrated that the fixed-sample stopping rule (FSR), in which the sample size is determined in advance, is less practical and efficient than are sequential-stopping rules. The composite limited adaptive sequential test (CLAST) is one such sequential-stopping rule. Previous research has shown that CLAST is more efficient in terms of sample size and power than are the FSR and other sequential rules and that it reflects more realistically the practice of experimental psychology researchers. The CLAST rule has been applied only to the t test of mean differences with two matched samples and to the chi-square independence test for twofold contingency tables. The present work extends previous research on the efficiency of CLAST to multiple group statistical tests. Simulation studies were conducted to test the efficiency of the CLAST rule for the one-way ANOVA for fixed effects models. The ANOVA general test and two linear contrasts of multiple comparisons among treatment means are considered. The article also introduces four rules for allocating N observations to J groups under the general null hypothesis and three allocation rules for the linear contrasts. Results show that the CLAST rule is generally more efficient than the FSR in terms of sample size and power for one-way ANOVA tests. However, the allocation rules vary in their optimality and have a differential impact on sample size and power. Thus, selecting an allocation rule depends on the cost of sampling and the intended precision.

  1. Experimental realization of a one-way quantum computer algorithm solving Simon's problem.

    PubMed

    Tame, M S; Bell, B A; Di Franco, C; Wadsworth, W J; Rarity, J G

    2014-11-14

    We report an experimental demonstration of a one-way implementation of a quantum algorithm solving Simon's problem-a black-box period-finding problem that has an exponential gap between the classical and quantum runtime. Using an all-optical setup and modifying the bases of single-qubit measurements on a five-qubit cluster state, key representative functions of the logical two-qubit version's black box can be queried and solved. To the best of our knowledge, this work represents the first experimental realization of the quantum algorithm solving Simon's problem. The experimental results are in excellent agreement with the theoretical model, demonstrating the successful performance of the algorithm. With a view to scaling up to larger numbers of qubits, we analyze the resource requirements for an n-qubit version. This work helps highlight how one-way quantum computing provides a practical route to experimentally investigating the quantum-classical gap in the query complexity model.

  2. One-way spatial integration of Navier-Stokes equations: stability of wall-bounded flows

    NASA Astrophysics Data System (ADS)

    Rigas, Georgios; Colonius, Tim; Towne, Aaron; Beyar, Michael

    2016-11-01

    For three-dimensional flows, questions of stability, receptivity, secondary flows, and coherent structures require the solution of large partial-derivative eigenvalue problems. Reduced-order approximations are thus required for engineering prediction since these problems are often computationally intractable or prohibitively expensive. For spatially slowly evolving flows, such as jets and boundary layers, a regularization of the equations of motion sometimes permits a fast spatial marching procedure that results in a huge reduction in computational cost. Recently, a novel one-way spatial marching algorithm has been developed by Towne & Colonius. The new method overcomes the principle flaw observed in Parabolized Stability Equations (PSE), namely the ad hoc regularization that removes upstream propagating modes. The one-way method correctly parabolizes the flow equations based on estimating, in a computationally efficient way, the local spectrum in each cross-stream plane and an efficient spectral filter eliminates modes with upstream group velocity. Results from the application of the method to wall-bounded flows will be presented and compared with predictions from the full linearized compressible Navier-Stokes equations and PSE.

  3. 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.

  4. Demonstration of Orbit Determination for the Lunar Reconnaissance Orbiter Using One-Way Laser Ranging Data

    NASA Technical Reports Server (NTRS)

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

    2016-01-01

    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. More over 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,November2010) 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 12h (approximately equals 6

  5. 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

  6. Demonstration of Orbit Determination for the Lunar Reconnaissance Orbiter Using One-Way Laser Ranging Data

    NASA Technical Reports Server (NTRS)

    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.

    2016-01-01

    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. More over 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,November2010) 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 12h (approximately equals 6

  7. A one-way shooting algorithm for transition path sampling of asymmetric barriers.

    PubMed

    Brotzakis, Z Faidon; Bolhuis, Peter G

    2016-10-28

    We present a novel transition path sampling shooting algorithm for the efficient sampling of complex (biomolecular) activated processes with asymmetric free energy barriers. The method employs a fictitious potential that biases the shooting point toward the transition state. The method is similar in spirit to the aimless shooting technique by Peters and Trout [J. Chem. Phys. 125, 054108 (2006)], but is targeted for use with the one-way shooting approach, which has been shown to be more effective than two-way shooting algorithms in systems dominated by diffusive dynamics. We illustrate the method on a 2D Langevin toy model, the association of two peptides and the initial step in dissociation of a β-lactoglobulin dimer. In all cases we show a significant increase in efficiency.

  8. A one-way shooting algorithm for transition path sampling of asymmetric barriers

    NASA Astrophysics Data System (ADS)

    Brotzakis, Z. Faidon; Bolhuis, Peter G.

    2016-10-01

    We present a novel transition path sampling shooting algorithm for the efficient sampling of complex (biomolecular) activated processes with asymmetric free energy barriers. The method employs a fictitious potential that biases the shooting point toward the transition state. The method is similar in spirit to the aimless shooting technique by Peters and Trout [J. Chem. Phys. 125, 054108 (2006)], but is targeted for use with the one-way shooting approach, which has been shown to be more effective than two-way shooting algorithms in systems dominated by diffusive dynamics. We illustrate the method on a 2D Langevin toy model, the association of two peptides and the initial step in dissociation of a β-lactoglobulin dimer. In all cases we show a significant increase in efficiency.

  9. One-way Tamm plasmon polaritons at the interface between magnetophotonic crystals and conducting metal oxides

    NASA Astrophysics Data System (ADS)

    Dong, Hui Yuan; Wang, Jin; Cui, Tie Jun

    2013-01-01

    We demonstrate theoretically the existence of one-way Tamm plasmon polaritons on the interface between magnetophotonic crystals and conducting metal oxides. In contrast to conventional surface plasmon-polaritons (SPPs), Tamm plasmon polaritons (TPPs) occur at frequencies above the bulk plasma frequency of the conducting materials, provided that the dispersion curves of such surface modes lie outside the light cone for the conducting oxides and simultaneously fall into the photonic band gap of the magnetophotonic crystal. The nonreciprocal properties of TPPs are caused by violation of the periodicity and time-reversal symmetry in the structure. Calculations on the field distribution and transmission spectra through the structure are employed to confirm the theoretical results, which could potentially impact on a broad range of SPP-related phenomena in applications.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. Optimal sample size allocation for Welch's test in one-way heteroscedastic ANOVA.

    PubMed

    Shieh, Gwowen; Jan, Show-Li

    2015-06-01

    The determination of an adequate sample size is a vital aspect in the planning stage of research studies. A prudent strategy should incorporate all of the critical factors and cost considerations into sample size calculations. This study concerns the allocation schemes of group sizes for Welch's test in a one-way heteroscedastic ANOVA. Optimal allocation approaches are presented for minimizing the total cost while maintaining adequate power and for maximizing power performance for a fixed cost. The commonly recommended ratio of sample sizes is proportional to the ratio of the population standard deviations or the ratio of the population standard deviations divided by the square root of the ratio of the unit sampling costs. Detailed numerical investigations have shown that these usual allocation methods generally do not give the optimal solution. The suggested procedures are illustrated using an example of the cost-efficiency evaluation in multidisciplinary pain centers.

  16. One-way rotation of a molecule-rotor driven by a shot noise.

    PubMed

    Echeverria, Jorge; Monturet, Serge; Joachim, Christian

    2014-03-07

    The shot noise of a tunneling current passing through a molecule-motor can sustain a one-way rotation when populating the molecular excited states by tunneling inelastic excitations. We demonstrate that a ratchet-like ground state rotation potential energy curve is not necessary for the rotation to occur. A relative shift in energy difference between the maxima of this ground state and the minima of the excited states is the necessary condition to get to a unidirectional rotation. The rotor speed of rotation and its rotation direction are both controlled by this shift, indicating the necessity of a careful design of both the ground and excited states of the next generation of molecule-motors to be able to generate a motive power at the nanoscale.

  17. Gencrypt: one-way cryptographic hashes to detect overlapping individuals across samples

    PubMed Central

    Turchin, Michael C.; Hirschhorn, Joel N.

    2012-01-01

    Summary: Meta-analysis across genome-wide association studies is a common approach for discovering genetic associations. However, in some meta-analysis efforts, individual-level data cannot be broadly shared by study investigators due to privacy and Institutional Review Board concerns. In such cases, researchers cannot confirm that each study represents a unique group of people, leading to potentially inflated test statistics and false positives. To resolve this problem, we created a software tool, Gencrypt, which utilizes a security protocol known as one-way cryptographic hashes to allow overlapping participants to be identified without sharing individual-level data. Availability: Gencrypt is freely available under the GNU general public license v3 at http://www.broadinstitute.org/software/gencrypt/ Contact: joelh@broadinstitute.org Supplementary information: Supplementary data are available at Bioinformatics online. PMID:22302573

  18. Analysis of one-way laser ranging data to LRO, time transfer and clock characterization

    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.

    2017-02-01

    We processed and analyzed one-way laser ranging data from International Laser Ranging Service ground stations to NASA's Lunar Reconnaissance Orbiter (LRO), obtained from June 13, 2009 until September 30, 2014. We pair and analyze the one-way range observables from station laser fire and spacecraft laser arrival times by using nominal LRO orbit models based on the GRAIL gravity field. We apply corrections for instrument range walk, as well as for atmospheric and relativistic effects. In total we derived a tracking data volume of ≈ 3000 hours featuring 64 million Full Rate and 1.5 million Normal Point observations. From a statistical analysis of the dataset we evaluate the experiment and the ground station performance. We observe a laser ranging measurement precision of 12.3 cm in case of the Full Rate data which surpasses the LOLA timestamp precision of 15 cm. The averaging to Normal Point data further reduces the measurement precision to 5.6 cm. We characterized the LRO clock with fits throughout the mission time and estimated the rate to 6.9 × 10-8, the aging to 1.6 × 10-12/day and the change of aging to 2.3 × 10-14 /day2over all mission phases. The fits also provide referencing of onboard time to the TDB time scale at a precision of 166 ns over two and 256 ns over all mission phases, representing ground to space time transfer. Furthermore we measure ground station clock differences from the fits as well as from simultaneous passes which we use for ground to ground time transfer from common view observations. We observed relative offsets ranging from 33 to 560 ns and relative rates ranging from 2 × 10-13 to 6 × 10-12 between the ground station clocks during selected mission phases. We study the results from the different methods and discuss their applicability for time transfer.

  19. 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.

  20. Non-reciprocity and topology in optics: one-way road for light via surface magnon polariton.

    PubMed

    Ochiai, Tetsuyuki

    2015-02-01

    We show how non-reciprocity and topology are used to construct an optical one-way waveguide in the Voigt geometry. First, we present a traditional approach of the one-way waveguide of light using surface polaritons under a static magnetic field. Second, we explain a recent discovery of a topological approach using photonic crystals with the magneto-optical coupling. Third, we present a combination of the two approaches, toward a broadband one-way waveguide in the microwave range.

  1. Analysis of One-Way Laser Ranging Data to LRO, Time Transfer and Clock Characterization

    NASA Technical Reports Server (NTRS)

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

    2016-01-01

    We processed and analyzed one-way laser ranging data from International Laser Ranging Service ground stations to NASA's Lunar Reconnaissance Orbiter (LRO), obtained from June 13, 2009 until September 30, 2014. We pair and analyze the one-way range observables from station laser fire and spacecraft laser arrival times by using nominal LRO orbit models based on the GRAIL gravity field. We apply corrections for instrument range walk, as well as for atmospheric and relativistic effects. In total we derived a tracking data volume of approximately 3000 hours featuring 64 million Full Rate and 1.5 million Normal Point observations. From a statistical analysis of the dataset we evaluate the experiment and the ground station performance. We observe a laser ranging measurement precision of 12.3 centimeters in case of the Full Rate data which surpasses the LOLA (Lunar Orbiting Laser Altimeter) timestamp precision of 15 centimeters. The averaging to Normal Point data further reduces the measurement precision to 5.6 centimeters. We characterized the LRO clock with fits throughout the mission time and estimated the rate to 6.9 times10 (sup -8), the aging to 1.6 times 10 (sup -12) per day and the change of aging to 2.3 times 10 (sup -14) per day squared over all mission phases. The fits also provide referencing of onboard time to the TDB (Barycentric Dynamical Time) time scale at a precision of 166 nanoseconds over two and 256 nanoseconds over all mission phases, representing ground to space time transfer. Furthermore we measure ground station clock differences from the fits as well as from simultaneous passes which we use for ground to ground time transfer from common view observations. We observed relative offsets ranging from 33 to 560 nanoseconds and relative rates ranging from 2 times 10 (sup -13) to 6 times 10 (sup -12) between the ground station clocks during selected mission phases. We study the results from the different methods and discuss their applicability for time

  2. Checking Questionable Entry of Personally Identifiable Information Encrypted by One-Way Hash Transformation.

    PubMed

    Chen, Xianlai; Fann, Yang C; McAuliffe, Matthew; Vismer, David; Yang, Rong

    2017-02-17

    As one of the several effective solutions for personal privacy protection, a global unique identifier (GUID) is linked with hash codes that are generated from combinations of personally identifiable information (PII) by a one-way hash algorithm. On the GUID server, no PII is permitted to be stored, and only GUID and hash codes are allowed. The quality of PII entry is critical to the GUID system. The goal of our study was to explore a method of checking questionable entry of PII in this context without using or sending any portion of PII while registering a subject. According to the principle of GUID system, all possible combination patterns of PII fields were analyzed and used to generate hash codes, which were stored on the GUID server. Based on the matching rules of the GUID system, an error-checking algorithm was developed using set theory to check PII entry errors. We selected 200,000 simulated individuals with randomly-planted errors to evaluate the proposed algorithm. These errors were placed in the required PII fields or optional PII fields. The performance of the proposed algorithm was also tested in the registering system of study subjects. There are 127,700 error-planted subjects, of which 114,464 (89.64%) can still be identified as the previous one and remaining 13,236 (10.36%, 13,236/127,700) are discriminated as new subjects. As expected, 100% of nonidentified subjects had errors within the required PII fields. The possibility that a subject is identified is related to the count and the type of incorrect PII field. For all identified subjects, their errors can be found by the proposed algorithm. The scope of questionable PII fields is also associated with the count and the type of the incorrect PII field. The best situation is to precisely find the exact incorrect PII fields, and the worst situation is to shrink the questionable scope only to a set of 13 PII fields. In the application, the proposed algorithm can give a hint of questionable PII entry

  3. Analysis of One-Way Laser Ranging Data to LRO, Time Transfer and Clock Characterization

    NASA Technical Reports Server (NTRS)

    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.

    2016-01-01

    We processed and analyzed one-way laser ranging data from International Laser Ranging Service ground stations to NASA's Lunar Reconnaissance Orbiter (LRO), obtained from June 13, 2009 until September 30, 2014. We pair and analyze the one-way range observables from station laser fire and spacecraft laser arrival times by using nominal LRO orbit models based on the GRAIL gravity field. We apply corrections for instrument range walk, as well as for atmospheric and relativistic effects. In total we derived a tracking data volume of approximately 3000 hours featuring 64 million Full Rate and 1.5 million Normal Point observations. From a statistical analysis of the dataset we evaluate the experiment and the ground station performance. We observe a laser ranging measurement precision of 12.3 centimeters in case of the Full Rate data which surpasses the LOLA (Lunar Orbiting Laser Altimeter) timestamp precision of 15 centimeters. The averaging to Normal Point data further reduces the measurement precision to 5.6 centimeters. We characterized the LRO clock with fits throughout the mission time and estimated the rate to 6.9 times10 (sup -8), the aging to 1.6 times 10 (sup -12) per day and the change of aging to 2.3 times 10 (sup -14) per day squared over all mission phases. The fits also provide referencing of onboard time to the TDB (Barycentric Dynamical Time) time scale at a precision of 166 nanoseconds over two and 256 nanoseconds over all mission phases, representing ground to space time transfer. Furthermore we measure ground station clock differences from the fits as well as from simultaneous passes which we use for ground to ground time transfer from common view observations. We observed relative offsets ranging from 33 to 560 nanoseconds and relative rates ranging from 2 times 10 (sup -13) to 6 times 10 (sup -12) between the ground station clocks during selected mission phases. We study the results from the different methods and discuss their applicability for time

  4. Checking Questionable Entry of Personally Identifiable Information Encrypted by One-Way Hash Transformation

    PubMed Central

    Chen, Xianlai; Fann, Yang C; McAuliffe, Matthew; Vismer, David

    2017-01-01

    Background As one of the several effective solutions for personal privacy protection, a global unique identifier (GUID) is linked with hash codes that are generated from combinations of personally identifiable information (PII) by a one-way hash algorithm. On the GUID server, no PII is permitted to be stored, and only GUID and hash codes are allowed. The quality of PII entry is critical to the GUID system. Objective The goal of our study was to explore a method of checking questionable entry of PII in this context without using or sending any portion of PII while registering a subject. Methods According to the principle of GUID system, all possible combination patterns of PII fields were analyzed and used to generate hash codes, which were stored on the GUID server. Based on the matching rules of the GUID system, an error-checking algorithm was developed using set theory to check PII entry errors. We selected 200,000 simulated individuals with randomly-planted errors to evaluate the proposed algorithm. These errors were placed in the required PII fields or optional PII fields. The performance of the proposed algorithm was also tested in the registering system of study subjects. Results There are 127,700 error-planted subjects, of which 114,464 (89.64%) can still be identified as the previous one and remaining 13,236 (10.36%, 13,236/127,700) are discriminated as new subjects. As expected, 100% of nonidentified subjects had errors within the required PII fields. The possibility that a subject is identified is related to the count and the type of incorrect PII field. For all identified subjects, their errors can be found by the proposed algorithm. The scope of questionable PII fields is also associated with the count and the type of the incorrect PII field. The best situation is to precisely find the exact incorrect PII fields, and the worst situation is to shrink the questionable scope only to a set of 13 PII fields. In the application, the proposed algorithm can

  5. Analysis of the characteristics of GRACE dual one-way ranging system

    NASA Astrophysics Data System (ADS)

    Ko, Ung Dai

    The motivation for this research was an improvement of the quality of the Earth's gravity solutions from the GRACE mission data through an instrument-level study. The objective was a better understanding of the characteristics and sources of the high-frequency noise in the range of (0.02 ˜ 0.1 Hz) in the dual one-way ranging (DOWR) and its effect on the gravity solution. For this purpose, the mathematical model of the DOWR observation was derived and the Allan variance was computed to establish an upper bound on the level of frequency instability of the ultra-stable oscillators (USO) to determine their contribution to the high-frequency noise. Because they are dominated by the high-frequency noise, the postfit residuals of the time derivative of the DOWR ranges were also examined to evaluate the contributions of various other factors such as system noise from the microwave signal receiver, external influences, and internal influences. The results indicate that the system noise is the dominant source of the excessive high-frequency noise. As one method of mitigation, a tighter bandwidth filter was applied to the DOWR processing, resulting in modest improvements in gravity solutions.

  6. Evidence-based practice guidelines--one way to enhance clinical practice.

    PubMed

    Bailes, Barbara K

    2002-06-01

    Abdominoplasty and liposuction guidelines are just two of the guidelines that can be accessed and used to enhance patient care. Guidelines also can be used to increase your knowledge about many other health care topics. The NGC has approved guidelines for managing chronic pain, as well as guidelines on chronic diseases (e.g., diabetes mellitus, hypertension, chronic obstructive pulmonary disease). Many patients have chronic diseases, and you or your family members also may be affected by chronic disorders. These guidelines provide you with a quick overview of evidence-based treatment protocols. These guidelines are not a panacea for evidence-based practice, but using them is one way that perioperative nurses can enhance their clinical skills. Though not everyone has personal Internet access, most health care facilities do or can make access a reality. Other options include medical or public libraries. Then one simply has to access the NGC web site and join other professionals in improving the quality and timeliness of patient care.

  7. 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.

  8. Effects of hippocampal stimulation on retention and extinction of one way active avoidance response in cats.

    PubMed

    Gralewicz, K; Gralewicz, S

    1984-01-01

    We found previously that hippocampal stimulation (HiSt) at 20 cps, 100 mikroA, applied jointly with a tone (500 Hz) CS in the course of retention test, improved the performance and retarded the extinction of one way active avoidance response (AAR) in cats. During this test failures to perform the AAR were not punished in all but two trials it the beginning of each session. The first experiment of the present studies demonstrated that - (i) the AAR facilitating the effect of HiSt might be prevented by m all electrolytic lesions made around the tips of the stimulating electrodes, (ii) large lesions of the hippocampus exerted little effect on the AAR acquisition, but the response was extinguished faster during the retention test. In the second experiment two response prevention trials (non-reinforced presentations of the CS with no possibility to make the AAR) were run at the beginning of each session after the end of training. In these conditions the HiSt resulted in a faster extinction of the AAR as compared with implanted unstimulated animals. Large lesions of the hippocampus had no effect on the extinction rate. We conclude that the facilitation of retrieval from memory may be responsible for the effects of HiSt on conditioned behavior.

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

    PubMed

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

    2016-04-22

    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.

  10. 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

  11. Building of one-way Hadamard gate for squeezed coherent states

    NASA Astrophysics Data System (ADS)

    Podoshvedov, Sergey A.

    2013-01-01

    We present an optical scheme to conditionally generate even or odd squeezed superpositions of coherent states (SSCSs). The optical setup consists of an unbalanced beam splitter whose transmittance tends to unity, and additional balanced beam splitters and photodetectors in auxiliary modes. Squeezed coherent states with different amplitudes are the input states in the optical scheme. The single-qubit operations are probabilistic and employ two- and three-photon subtractions from initial beams as the driving force. Generation of the even or odd SSCSs is observed in a wide diapason of values of used parameters. We consider a possibility to realize a one-way Hadamard gate for the squeezed coherent states when the base states are transformed into superposition states. States approximating the output states of a Hadamard gate with high fidelity can be realized by imposing restrictions on the values of used parameters. Higher-order subtractions from input beams are necessary to generate the SSCSs with larger amplitudes and higher fidelities. The problem is resolved in a Wigner representation to take into account imperfections of the optical devices.

  12. 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.

  13. Check valve

    DOEpatents

    Upton, H.A.; Garcia, P.

    1999-08-24

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

  14. 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.

  15. 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.

  16. 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

    2016-07-08

    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.

  17. 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

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

    SciTech Connect

    Kondo, Tomoki; Ando, Keita

    2016-03-15

    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.

  19. Non-reciprocity and topology in optics: one-way road for light via surface magnon polariton

    PubMed Central

    Ochiai, Tetsuyuki

    2015-01-01

    We show how non-reciprocity and topology are used to construct an optical one-way waveguide in the Voigt geometry. First, we present a traditional approach of the one-way waveguide of light using surface polaritons under a static magnetic field. Second, we explain a recent discovery of a topological approach using photonic crystals with the magneto-optical coupling. Third, we present a combination of the two approaches, toward a broadband one-way waveguide in the microwave range. PMID:27877739

  20. COBE navigation with one-way return-link Doppler in the post-helium-venting phase

    NASA Astrophysics Data System (ADS)

    Dunham, Joan; Nemesure, M.; Samii, M. V.; Maher, M.; Teles, Jerome; Jackson, J.

    1991-12-01

    The results of a navigation experiment with one way return link Doppler tracking measurements for operational orbit determination of the Cosmic Background Explorer (COBE) spacecraft are presented. The frequency of the tracking signal for the one way measurements was stabilized with an Ultrastable Oscillator (USO), and the signal was relayed by the Tracking and Data Relay Satellite System (TDRSS). The study achieved three objectives: space qualification of TDRSS noncoherent one way return link Doppler tracking; determination of flight performance of the USO coupled to the second generation TDRSS compatible user transponder; and verification of algorithms for navigation using actual one way tracking data. Orbit determination and the inflight USO performance evaluation results are presented.

  1. Fast valve

    SciTech Connect

    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.

  2. 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.

  3. Selective, Spontaneous One-Way Oil-Transport Fabrics and Their Novel Use for Gauging Liquid Surface Tension.

    PubMed

    Wang, Hongxia; Zhou, Hua; Yang, Weidong; Zhao, Yan; Fang, Jian; Lin, Tong

    2015-10-21

    Thin porous materials that can spontaneously transport oil fluids just in a single direction have great potential for making energy-saving functional membranes. However, there is little data for the preparation and functionalities of this smart material. Here, we report a novel method to prepare one-way oil-transport fabrics and their application in detecting liquid surface tension. This functional fabric was prepared by a two-step coating process to apply flowerlike ZnO nanorods, fluorinated decyl polyhedral oligomeric silsesquioxanes, and hydrolyzed fluorinated alkylsilane on a fabric substrate. Upon one-sided UV irradiation, the coated fabric shows a one-way transport feature that allows oil fluid transport automatically from the unirradiated side to the UV-irradiated surface, but it stops fluid transport in the opposite direction. The fabric still maintains high superhydrophobicity after UV treatment. The one-way fluid transport takes place only for the oil fluids with a specific surface tension value, and the fluid selectivity is dependent on the UV treatment time. Changing the UV irradiation time from 6 to 30 h broadened the one-way transport for fluids with surface tension from around 22.3 mN/m to a range of 22.3-56.7 mN/m. We further proved that this selective one-way oil transport can be used to estimate the surface tension of a liquid simply by observing its transport feature on a series of fabrics with different one-way oil-transport selectivities. To our knowledge, this is the first example to use one-way fluid-transport materials for testing the liquid surface tension. It may open up further theoretical studies and the development of novel fluid sensors.

  4. 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.

  5. Mechanism of one-way traffic of hexameric phi29 DNA packaging motor with four electropositive relaying layers facilitating antiparallel revolution.

    PubMed

    Zhao, Zhengyi; Khisamutdinov, Emil; Schwartz, Chad; Guo, Peixuan

    2013-05-28

    The importance of nanomotors in nanotechnology is akin to that of mechanical engines to daily life. The AAA+ superfamily is a class of nanomotors performing various functions. Their hexagonal arrangement facilitates bottom-up assembly for stable structures. The bacteriophage phi29 DNA translocation motor contains three coaxial rings: a dodecamer channel, a hexameric ATPase ring, and a hexameric pRNA ring. The viral DNA packaging motor has been believed to be a rotational machine. However, we discovered a revolution mechanism without rotation. By analogy, the earth revolves around the sun while rotating on its own axis. One-way traffic of dsDNA translocation is facilitated by five factors: (1) ATPase changes its conformation to revolve dsDNA within a hexameric channel in one direction; (2) the 30° tilt of the channel subunits causes an antiparallel arrangement between two helices of dsDNA and channel wall to advance one-way translocation; (3) unidirectional flow property of the internal channel loops serves as a ratchet valve to prevent reversal; (4) 5'-3' single-direction movement of one DNA strand along the channel wall ensures single direction; and (5) four electropositive layers interact with one strand of the electronegative dsDNA phosphate backbone, resulting in four relaying transitional pauses during translocation. The discovery of a riding system along one strand provides a motion nanosystem for cargo transportation and a tool for studying force generation without coiling, friction, and torque. The revolution of dsDNA among 12 subunits offers a series of recognition sites on the DNA backbone to provide additional spatial variables for nucleotide discrimination for sensing applications.

  6. Mechanism of One-Way Traffic of Hexameric Phi29 DNA Packaging Motor with Four Electropositive Relaying Layers Facilitating Antiparallel Revolution

    PubMed Central

    2013-01-01

    The importance of nanomotors in nanotechnology is akin to that of mechanical engines to daily life. The AAA+ superfamily is a class of nanomotors performing various functions. Their hexagonal arrangement facilitates bottom-up assembly for stable structures. The bacteriophage phi29 DNA translocation motor contains three coaxial rings: a dodecamer channel, a hexameric ATPase ring, and a hexameric pRNA ring. The viral DNA packaging motor has been believed to be a rotational machine. However, we discovered a revolution mechanism without rotation. By analogy, the earth revolves around the sun while rotating on its own axis. One-way traffic of dsDNA translocation is facilitated by five factors: (1) ATPase changes its conformation to revolve dsDNA within a hexameric channel in one direction; (2) the 30° tilt of the channel subunits causes an antiparallel arrangement between two helices of dsDNA and channel wall to advance one-way translocation; (3) unidirectional flow property of the internal channel loops serves as a ratchet valve to prevent reversal; (4) 5′–3′ single-direction movement of one DNA strand along the channel wall ensures single direction; and (5) four electropositive layers interact with one strand of the electronegative dsDNA phosphate backbone, resulting in four relaying transitional pauses during translocation. The discovery of a riding system along one strand provides a motion nanosystem for cargo transportation and a tool for studying force generation without coiling, friction, and torque. The revolution of dsDNA among 12 subunits offers a series of recognition sites on the DNA backbone to provide additional spatial variables for nucleotide discrimination for sensing applications. PMID:23510192

  7. More than one way to be happy: a typology of marital happiness.

    PubMed

    Rauer, Amy; Volling, Brenda

    2013-09-01

    This study utilized observational and self-report data from 57 happily married couples to explore assumptions regarding marital happiness. Suggesting that happily married couples are not a homogeneous group, cluster analyses revealed the existence of three types of couples based on their observed behaviors in a problem-solving task: (1) mutually engaged couples (characterized by both spouses' higher negative and positive problem-solving); (2) mutually supportive couples (characterized by both spouses' higher positivity and support); and (3) wife compensation couples (characterized by high wife positivity). Although couples in all three clusters were equally happy with and committed to their marriages, these clusters were differentially associated with spouses' evaluations of their marriage. Spouses in the mutually supportive cluster reported greater intimacy and maintenance and less conflict and ambivalence, although this was more consistently the case in comparison to the wife compensation cluster, as opposed to the mutually engaged cluster. The implications of these typologies are discussed as they pertain to efforts on the part of both practitioners to promote marital happiness and repair marital relations when couples are faced with difficulties.

  8. One-way optical modal transition based on causality in momentum space.

    PubMed

    Yu, Sunkyu; Piao, Xianji; Yoo, KyungWan; Shin, Jonghwa; Park, Namkyoo

    2015-09-21

    The concept of parity-time (PT) symmetry has been used to identify a route toward unidirectional dynamics in optical k-space: imposing asymmetry on the flow of light. Although PT-symmetric potentials have been implemented under the requirement of V(x) = V*(-x), this precondition has only been interpreted within the mathematical framework for the symmetry of Hamiltonians and has not been directly linked to unidirectionality induced by PT symmetry. In this paper, within the context of light-matter interactions, we develop an alternative route toward unidirectionality in k-space by employing the concept of causality. We demonstrate that potentials with real and causal momentum spectra produce unidirectional transitions of optical modes inside the k-continuum, which corresponds to an exceptional point on the degree of PT symmetry. Our analysis reveals a critical link between non-Hermitian problems and spectral theory and also enables multi-dimensional designer manipulation of optical modes, in contrast to the one-dimensional approach that used a Schrödinger-like equation in previous PT-symmetric optics.

  9. One-way self-collimated acoustic beams in two-dimensional asymmetric sonic crystals with circulating fluids

    NASA Astrophysics Data System (ADS)

    Zhang, Ting; Cheng, Ying; Liu, XiaoJun

    2017-06-01

    We theoretically realized the one-way self-collimation effect of acoustic beams in two-dimensional sonic crystals (SCs), which are composed of irregular rigid rods surrounded by circulating fluids. The parity symmetry (P symmetry) and time-reversal symmetry (T symmetry) of the circulating-fluid SCs (CFSCs) are broken by the asymmetric crystal lattice and the circulating fluids. A large isolation of >30 dB with a maintained wavefront and frequency is realized for output acoustic beams launched in opposite directions. By applying the gradient angular velocities of the circulating fluids, the one-way self-collimated acoustic beams can be bent gradually, yielding an acoustic mirage effect. The one-way self-collimation in CFSCs provides an avenue for manipulating acoustic beams independently of the nonlinearity and mode conversion.

  10. Get valves repaired properly

    SciTech Connect

    Robert, R.W.

    1988-02-01

    Valve users are generally unanimous in their dissatisfaction with valve reconditioning programs. Their dissatisfaction is expressed in three complaints: poor service, poor quality and total costs which often approach or exceed valve replacement costs. These complaints are clearly legitimate, and the providers of valve reconditioning services must shoulder a significant part of the blame. However, scrutiny of the reasons for dissatisfaction reveals that some portion of the blame must also be borne by the users. Since many of the practices that cause the user's complaints are rooted in the early development of this market, a review of that development is helpful in understanding how these problems arose, and leads to a better understanding of the steps necessary for improvement.

  11. Problem: Heart Valve Stenosis

    MedlinePlus

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

  12. Nonparametric One-Way Multivariate Analysis of Variance: A Computational Approach Based on the Pillai-Bartlett Trace.

    ERIC Educational Resources Information Center

    Zwick, Rebecca

    1985-01-01

    Describes how the test statistic for nonparametric one-way multivariate analysis of variance can be obtained by submitting the data to a packaged computer program. Monte Carlo evidence indicates that the nonparametric approach is advantageous under certain violations of the assumptions of multinormality and homogeneity of covariance matrices.…

  13. Constant Time Delay: One Way to Provide Positive Behavioral Support for Students with Emotional and Behavioral Disorders

    ERIC Educational Resources Information Center

    Stevens, Kay B.; Lingo, Amy S.

    2005-01-01

    Teachers of students with emotional and behavioral disorders (EBD) understand conceptually, emotionally, and legally the importance of using research-based procedures as well as positive behavioral supports. One way to provide positive behavioral support for students with EBD is constant time delay (CTD). CTD is an instructional delivery procedure…

  14. 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)

  15. 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…

  16. Effect of one-way clutch on the nonlinear vibration of belt-drive systems with a continuous belt model

    NASA Astrophysics Data System (ADS)

    Ding, Hu; Zu, Jean W.

    2013-11-01

    This study focuses on the nonlinear steady-state response of a belt-drive system with a one-way clutch. A dynamic model is established to describe the rotations of the driving pulley, the driven pulley, and the accessory shaft. Moreover, the model considers the transverse vibration of the translating belt spans for the first time in belt-drive systems coupled with a one-way clutch. The excitation of the belt-drive system is derived from periodic fluctuation of the driving pulley. In automotive systems, this kind of fluctuation is induced by the engine firing harmonic pulsations. The derived coupled discrete-continuous nonlinear equations consist of integro-partial-differential equations and piece-wise ordinary differential equations. Using the Galerkin truncation, a set of nonlinear ordinary differential equations is obtained from the integro-partial-differential equations. Applying the Runge-Kutta time discretization, the time histories of the dynamic response are numerically solved for the driven pulley and the accessory shaft and the translating belt spans. The resonance areas of the coupled belt-drive system are determined using the frequency sweep. The effects of the one-way clutch on the belt-drive system are studied by comparing the frequency-response curves of the translating belt with and without one-way clutch device. Furthermore, the results of 2-term and 4-term Galerkin truncation are compared to determine the numerical convergence. Moreover, parametric studies are conducted to understand the effects of the system parameters on the nonlinear steady-state response. It is concluded that one-way clutch not only decreases the resonance amplitude of the driven pulley and shaft's rotational vibration, but also reduces the resonance region of the belt's transverse vibration.

  17. 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.

  18. 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

  19. High-performance one-way transmission using pyramid-shaped silicon grating-coupled hyperbolic metamaterial

    NASA Astrophysics Data System (ADS)

    Hu, Jigang; Qing, Yeming; Wen, Zhengqian; Wu, Xiaohang; Ren, Rongze; Gao, Weiqing; Li, Dongmei; Gao, Feng

    2016-11-01

    An asymmetric transmission device has been presented to realize high-performance one-way transmission at visible frequencies. This device consists of a pair of non-symmetric pyramid-shaped silicon gratings separated by a metal/dielectric multilayer structure (MDMS). Simulation results demonstrates that, compared with conventional Cr grating, MDMS with pyramid-shaped silicon gratings will greatly enhance the coupling and decoupling between the propagating waves in free space and the high frequency modes in MDMS, rendering an improved oneway transmission performance. The improved one-way transmission performance offered by our design may hold great potential in designing the optical isolator and polarizer for ultra-compact photonic integrated circuit.

  20. Lower bounds for the security of modified coherent-one-way quantum key distribution against one-pulse-attack

    NASA Astrophysics Data System (ADS)

    Li, Hong-Wei; Yin, Zhen-Qiang; Wang, Shuang; Chen, Wei; Han, Zheng-Fu; Bao, Wan-Su; Guo, Guang-Can

    2011-02-01

    Upper bounds for the security of coherent-one-way (COW) quantum key distribution protocols have been analyzed by considering the one-pulse-attack [Branciard C, Gisin N and Scarani V (BGS) New J.Phys. (2008) 10 013031]. However, their security analysis was based on long distance case, and the typical value of the transmission distance is larger than 50 km. Applying the sharp continuity for the von Neumann entropy and some basic inequalities, we provide lower bounds for the security of modified coherent-one-way quantum key distribution protocol against the most general one-pulse-attack by only considering photon number resolved detectors that will be used in the receiver's side. Comparing with BGS's security analysis, our security analysis can be satisfied with arbitrary distance case.

  1. 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.

  2. Exhaled flow monitoring can detect bronchial flap-valve obstruction in a mechanical lung model.

    PubMed

    Breen, P H; Serina, E R; Barker, S J

    1995-08-01

    Flap-valve obstruction to expiratory flow (V) in a major bronchus can result from inspissated secretions, blood, or foreign body. During inhalation, increasing airway caliber preserves inspired V past the obstruction; during exhalation, decreasing airway diameter causes airflow obstruction and even frank gas trapping. We reasoned that the resultant sequential, biphasic exhalation of the lungs would be best detected by measuring exhaled V versus time. Accordingly, we designed an airway obstruction element in a mechanical lung model to examine flap-valve bronchial obstruction. A mechanical lung simulator was ventilated with a pressure-limited flow generator, where f = 10/min, tidal volume = 850 mL, and respiratory compliance = 40 mL/cm H2O. Airway V (pneumotachometer) and pressure (P) were digitally sampled for 1 min. Then, the circumference of the diaphragm in a respiratory one-way valve was trimmed to generate unidirectional resistance to expiratory V. Measurement sequences were repeated after this flap-valve was interposed in the right "main-stem bronchus." Integration of airway V versus time generated changes in lung volume. During flap-valve obstruction of the right bronchus, the V-time plot revealed preservation of peak expired flow from the normal lung, followed by retarded and decreased flow from the obstructed right lung. Gas trapping of the obstructed lung occurred during conditions of decreased expiratory time and increased expiratory resistance. Airway P could not differentiate between bronchial and tracheal flap-valve obstruction because P decreased abruptly in both conditions. The flow-volume loop displayed less distinctive changes than the flow-time plot, in part because the flow-volume loop was data (flow) plotted against its time integral (volume), with loss of temporal data. In this mechanical lung model, we conclude that bronchial flap-valve obstruction was best detected by the flow-time plot, which could measure the sequential emptying of the

  3. Prosthetic valve endocarditis: an overview.

    PubMed

    Gnann, J W; Dismukes, W E

    1983-12-01

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

  4. 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.

  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. Experimental realization of one-way quantum computing with two-photon four-qubit cluster states.

    PubMed

    Chen, Kai; Li, Che-Ming; Zhang, Qiang; Chen, Yu-Ao; Goebel, Alexander; Chen, Shuai; Mair, Alois; Pan, Jian-Wei

    2007-09-21

    We report an experimental realization of one-way quantum computing on a two-photon four-qubit cluster state. This is accomplished by developing a two-photon cluster state source entangled both in polarization and spatial modes. With this special source, we implemented a highly efficient Grover's search algorithm and high-fidelity two-qubit quantum gates. Our experiment demonstrates that such cluster states could serve as an ideal source and a building block for rapid and precise optical quantum computation.

  7. Aortic Valve Regurgitation

    MedlinePlus

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

  8. Aortic Valve Stenosis

    MedlinePlus

    ... pulmonary valve and aortic valve. Each valve has flaps (cusps or leaflets) that open and close once ... valve consists of three tightly fitting, triangular-shaped flaps of tissue called cusps. Some children are born ...

  9. Comparison of one-way and two-way coupled analyses of electromagnetic machines considering magnetic and structural interactions

    NASA Astrophysics Data System (ADS)

    Nam, Jahyun; Kang, Chiho; Song, Jeongyong; Jang, Gunhee

    2017-05-01

    We compared one-way and two-way coupled analyses of electromagnetic machines considering magnetic and structural interaction to identify the frequency components of magnetic excitation and to determine the structural coupling effects predicted only by the two-way coupled analysis. We developed finite element models of a C-core switch and an electric motor. In the two-way coupled analysis method, the magnetic force calculated by using the Maxwell stress tensor was applied to the structural finite element model to determine the elastic deformation, and the magnetic finite element model was rearranged by means of the moving mesh method to represent the structural elastic deformation. We showed that two-way coupled analysis predicted the excitation frequency of 80 Hz (4 times the input current frequency) of magnetic force in the C-core switch and the excitation frequency of 667 Hz (the first natural frequency of the rotor, corresponding to the translational mode) of magnetic force in the electric motor undergoing rotor eccentricity. We showed that two-way coupled analysis predicted magnetic excitation and its corresponding structural response more accurately than the one-way coupled analysis, especially for electromagnetic machines in which the structural deformation affects magnetic field through variation of the air gap length.

  10. 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.

  11. Multi-user quantum private comparison with scattered preparation and one-way convergent transmission of quantum states

    NASA Astrophysics Data System (ADS)

    Ye, TianYu; Ji, ZhaoXu

    2017-09-01

    Quantum private comparison (QPC) aims to accomplish the equality comparison of the secrets from different users without disclosing their genuine contents by using the principles of quantum mechanics. In this paper, we summarize eight modes of quantum state preparation and transmission existing in current QPC protocols first. Then, by using the mode of scattered preparation and one-way convergent transmission, we construct a new multi-user quantum private comparison (MQPC) protocol with two-particle maximally entangled states, which can accomplish arbitrary pair's comparison of equality among K users within one execution. Analysis turns out that its output correctness and its security against both the outside attack and the participant attack are guaranteed. The proposed MQPC protocol can be implemented with current technologies. It can be concluded that the mode of scattered preparation and one-way convergent transmission of quantum states is beneficial to designing the MQPC protocol which can accomplish arbitrary pair's comparison of equality among K users within one execution.

  12. Intimal sarcoma of the pulmonary valve.

    PubMed

    Scheidl, Stefan; Taghavi, Shahrokh; Reiter, Ursula; Tröster, Natascha; Kovacs, Gabor; Rienmüller, Rainer; Lang, Susanna; Klepetko, Walter; Olschewski, Horst

    2010-04-01

    Pulmonary artery intimal sarcoma is a rare tumor of the cardiovascular system. Intimal sarcoma of the pulmonary valve itself has not been described. Embolization into pulmonary arteries originating from the pulmonary valve intimal sarcoma can mimic chronic thromboembolic pulmonary hypertension and mislead the diagnosis. We present and discuss a patient initially diagnosed as chronic thromboembolic pulmonary hypertension, treated by pulmonary endarterectomy. After 24 months, a tumor of the pulmonary valve was detected by echocardiography. The patient underwent removal and replacement of the pulmonary valve. Histology revealed pulmonary valve intimal sarcoma.

  13. 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.

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

    PubMed

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

    2017-01-04

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

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. Wave Propagation, Scattering and Imaging Using Dual-domain One-way and One-return Propagators

    NASA Astrophysics Data System (ADS)

    Wu, R.-S.

    - Dual-domain one-way propagators implement wave propagation in heterogeneous media in mixed domains (space-wavenumber domains). One-way propagators neglect wave reverberations between heterogeneities but correctly handle the forward multiple-scattering including focusing/defocusing, diffraction, refraction and interference of waves. The algorithm shuttles between space-domain and wavenumber-domain using FFT, and the operations in the two domains are self-adaptive to the complexity of the media. The method makes the best use of the operations in each domain, resulting in efficient and accurate propagators. Due to recent progress, new versions of dual-domain methods overcame some limitations of the classical dual-domain methods (phase-screen or split-step Fourier methods) and can propagate large-angle waves quite accurately in media with strong velocity contrasts. These methods can deliver superior image quality (high resolution/high fidelity) for complex subsurface structures. One-way and one-return (De Wolf approximation) propagators can be also applied to wave-field modeling and simulations for some geophysical problems. In the article, a historical review and theoretical analysis of the Born, Rytov, and De Wolf approximations are given. A review on classical phase-screen or split-step Fourier methods is also given, followed by a summary and analysis of the new dual-domain propagators. The applications of the new propagators to seismic imaging and modeling are reviewed with several examples. For seismic imaging, the advantages and limitations of the traditional Kirchhoff migration and time-space domain finite-difference migration, when applied to 3-D complicated structures, are first analyzed. Then the special features, and applications of the new dual-domain methods are presented. Three versions of GSP (generalized screen propagators), the hybrid pseudo-screen, the wide-angle Padé-screen, and the higher-order generalized screen propagators are discussed. Recent

  1. 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.

  2. Quantum cryptography with finite resources: unconditional security bound for discrete-variable protocols with one-way postprocessing.

    PubMed

    Scarani, Valerio; Renner, Renato

    2008-05-23

    We derive a bound for the security of quantum key distribution with finite resources under one-way postprocessing, based on a definition of security that is composable and has an operational meaning. While our proof relies on the assumption of collective attacks, unconditional security follows immediately for standard protocols such as Bennett-Brassard 1984 and six-states protocol. For single-qubit implementations of such protocols, we find that the secret key rate becomes positive when at least N approximately 10(5) signals are exchanged and processed. For any other discrete-variable protocol, unconditional security can be obtained using the exponential de Finetti theorem, but the additional overhead leads to very pessimistic estimates.

  3. Confidence intervals and sample size calculations for the weighted eta-squared effect sizes in one-way heteroscedastic ANOVA.

    PubMed

    Shieh, Gwowen

    2013-03-01

    Effect size reporting and interpreting practices have been extensively recommended in academic journals when primary outcomes of all empirical studies have been analyzed. This article presents an alternative approach to constructing confidence intervals of the weighted eta-squared effect size within the context of one-way heteroscedastic ANOVA models. It is shown that the proposed interval procedure has advantages over an existing method in its theoretical justification, computational simplicity, and numerical performance. For design planning, the corresponding sample size procedures for precise interval estimation of the weighted eta-squared association measure are also delineated. Specifically, the developed formulas compute the necessary sample sizes with respect to the considerations of expected confidence interval width and tolerance probability of interval width within a designated value. Supplementary computer programs are provided to aid the implementation of the suggested techniques in practical applications of ANOVA designs when the assumption of homogeneous variances is not tenable.

  4. Wide-angle elastic wave one-way propagation in heterogeneous media and an elastic wave complex-screen method

    NASA Astrophysics Data System (ADS)

    Wu, Ru-Shan

    1994-01-01

    In this paper a system of equations for wide-angle one-way elastic wave propagation in arbitrarily heterogeneous media is formulated in both the space and wavenumber domains using elastic Rayleigh integrals and local elastic Born scattering theory. The wavenumber domain formulation leads to compact solutions to one-way propagation and scattering problems. It is shown that wide-angle scattering in heterogeneous elastic media cannot be formulated as passage through regular phase-screens, since the interaction between the incident wavefield and the heterogeneities is not local in both the space domain and the wavenumber domain. Our more generally valid formulation is called the 'thin-slap; formulation. After applying the small-angle approximation, the thin slab effect degenerates to that of an elastic complex-screen (or generalized phase-screen). For the complex-screen method the cross-coupling term is neglected because it is higher order small quantity for small-angle scattering. Relative to prior derivations of vector phase-screen method, our method can correctly treat the conversion between P and S waves and the cross-coupling between differently polarized S waves. A comparison with solutions from three-dimensional finite difference and exact solutions using eigenfunctions expansion is made for two special cases. One is for a solid sphere with only P velocity pertubation; the other is with only S velocity perturbation. The Elastic complex-screen method generally agrees well with the three-dimensional finite difference method and the exact solutions. In the limiting case of scalar waves, the derivation in this paper leads to a move generally valid new method, namely, a scaler thin-slab method. When making the small-angle approximation to the interaction term while keeping the propagation term unchanged, the thin-slab method approaches the currently available scalar wide-angle phase screen method.

  5. 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.

  6. 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.

  7. Valve Disease

    MedlinePlus

    ... medicines for the rest of their lives. Valve surgery is usually an open heart technique. This means that surgeons use a heart-lung machine, because the heart must stop beating for a short time during surgery. In some patients, surgeons can repair or replace ...

  8. Rectification and one-way street for the energy current in boundary-driven asymmetric quantum spin chains.

    PubMed

    Pereira, Emmanuel

    2017-03-01

    Motivated by the demand for efficient quantum devices to engineer energy transport, we analyze some inhomogeneous quantum spin systems, including XXZ chains, with magnetization baths at the ends. With a goal of finding general properties, we study the effects of suitable transformations on the boundary-driven Lindblad master equation associated with the dynamics of the systems. For asymmetric models with target polarization at the edges or twisted XY boundary gradients, we show the properties of the steady state, which establish the features of the energy current irrespective of the system size and the regime of transport. We show the ubiquitous occurrence of energy rectification and, more interestingly, of an unusual phenomenon: in the absence of an external magnetic field, there is a one-way street for the energy current, i.e., the direction of the energy current does not change as we invert the magnetization baths at the boundaries. Given the extensiveness of the procedures, which essentially involve the properties of the Lindblad master equation, our results certainly follow for other interactions and other boundary conditions. Moreover, our results indicate graded spin chains as genuine quantum rectifiers.

  9. 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.

  10. One-way domain decomposition method with exact radiation condition and fast GMRES solver for the solution of Maxwell's equations

    NASA Astrophysics Data System (ADS)

    Stupfel, Bruno; Lecouvez, Matthieu

    2016-10-01

    For the solution of the time-harmonic electromagnetic scattering problem by inhomogeneous 3-D objects, a one-way domain decomposition method (DDM) is considered: the computational domain is partitioned into concentric subdomains on the interfaces of which Robin-type transmission conditions (TCs) are prescribed; an integral representation of the electromagnetic fields on the outer boundary constitutes an exact radiation condition. The global system obtained after discretization of the finite element (FE) formulations is solved via a Krylov subspace iterative method (GMRES). It is preconditioned in such a way that, essentially, only the solution of the FE subsystems in each subdomain is required. This is made possible by a computationally cheap H (curl)- H (div) transformation performed on the interfaces that separate the two outermost subdomains. The eigenvalues of the preconditioned matrix of the system are bounded by two, and optimized values of the coefficients involved in the local TCs on the interfaces are determined so as to maximize the minimum eigenvalue. Numerical experiments are presented that illustrate the numerical accuracy of this technique, its fast convergence, and legitimate the choices made for the optimized coefficients.

  11. A comparative study on the effectiveness of one-way printed communication versus videophone interactive interviews on health promotion.

    PubMed

    Homma, Satoki; Imamura, Haruhiko; Nakamura, Toru; Fujimura, Kaori; Ito, Yoshihiro; Maeda, Yuji; Kaneko, Ikuyo

    2016-01-01

    We performed a comparative study of a health education programme that was delivered either through one-way communication with printed media, or through interactive videophone interviews. We aimed to ascertain which mode of counselling, when used in combination with telemonitoring, is more effective at lifestyle modification intended to improve health status. Participants, who were residents of Kurihara city in Miyagi prefecture, Japan, were randomized into two groups: one group received individualized monthly documented reports (n = 33; 22 females; average age: 67.2 years), and the other received interactive videophone communication (n = 35; 22 females; average age: 65.1 years) for three months. Telemonitoring was conducted on both groups, using a pedometer, weighing scale and a sphygmomanometer. Pre- and post-intervention, anthropometric measurements and blood tests were performed; the participants also completed self-administered questionnaires. The two groups showed similar degrees of health status improvement and satisfaction levels. However, the participants in the videophone group were more aware of improvements in their lifestyles than were the participants in the document group. The individualized printed communication programme was less time-consuming compared to videophone communication. Further studies are needed to formulate a balanced protocol for a counselling-cum-telemonitoring programme that provides optimal health improvement and cost performance with the available human resources. © The Author(s) 2015.

  12. A Novel Approach for Constructing One-Way Hash Function Based on a Message Block Controlled 8D Hyperchaotic Map

    NASA Astrophysics Data System (ADS)

    Lin, Zhuosheng; Yu, Simin; Lü, Jinhu

    2017-06-01

    In this paper, a novel approach for constructing one-way hash function based on 8D hyperchaotic map is presented. First, two nominal matrices both with constant and variable parameters are adopted for designing 8D discrete-time hyperchaotic systems, respectively. Then each input plaintext message block is transformed into 8 × 8 matrix following the order of left to right and top to bottom, which is used as a control matrix for the switch of the nominal matrix elements both with the constant parameters and with the variable parameters. Through this switching control, a new nominal matrix mixed with the constant and variable parameters is obtained for the 8D hyperchaotic map. Finally, the hash function is constructed with the multiple low 8-bit hyperchaotic system iterative outputs after being rounded down, and its secure analysis results are also given, validating the feasibility and reliability of the proposed approach. Compared with the existing schemes, the main feature of the proposed method is that it has a large number of key parameters with avalanche effect, resulting in the difficulty for estimating or predicting key parameters via various attacks.

  13. 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.

  14. 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.

  15. Rectification and one-way street for the energy current in boundary-driven asymmetric quantum spin chains

    NASA Astrophysics Data System (ADS)

    Pereira, Emmanuel

    2017-03-01

    Motivated by the demand for efficient quantum devices to engineer energy transport, we analyze some inhomogeneous quantum spin systems, including X X Z chains, with magnetization baths at the ends. With a goal of finding general properties, we study the effects of suitable transformations on the boundary-driven Lindblad master equation associated with the dynamics of the systems. For asymmetric models with target polarization at the edges or twisted X Y boundary gradients, we show the properties of the steady state, which establish the features of the energy current irrespective of the system size and the regime of transport. We show the ubiquitous occurrence of energy rectification and, more interestingly, of an unusual phenomenon: in the absence of an external magnetic field, there is a one-way street for the energy current, i.e., the direction of the energy current does not change as we invert the magnetization baths at the boundaries. Given the extensiveness of the procedures, which essentially involve the properties of the Lindblad master equation, our results certainly follow for other interactions and other boundary conditions. Moreover, our results indicate graded spin chains as genuine quantum rectifiers.

  16. 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.

  17. 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.

  18. Dump valve

    SciTech Connect

    Webber, J.C.

    1981-06-23

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

  19. 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)

  20. The aortic valve microenvironment and its role in calcific aortic valve disease.

    PubMed

    Yip, Cindy Ying Yin; Simmons, Craig A

    2011-01-01

    In calcific aortic valve disease, fibrotic and calcific lesions form focally in the fibrosa layer of the valve leaflets. Layer-specific pathosusceptibility suggests that the fibrosa microenvironment is permissive to pathological development. The cellular microenvironment in the aortic valve is defined by a variety of biomechanical-, biochemical-, and extracellular-mediated factors, some of which are unique to the fibrosa. Growing evidence supports the role of these microenvironmental cues in the local regulation of side-specific valve cell phenotypes and focal pathological alterations, revealing new insights into the cellular and molecular processes that contribute to calcific aortic valve disease. Copyright © 2011 Elsevier Inc. All rights reserved.

  1. 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…

  2. 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…

  3. 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

  4. Particle transport and flow modification in planar temporally evolving laminar mixing layers. I. Particle transport under one-way coupling

    NASA Astrophysics Data System (ADS)

    Narayanan, Chidambaram; Lakehal, Djamel

    2006-09-01

    Simulations of two-dimensional, particle-laden mixing layers were performed for particles with Stokes numbers of 0.3, 0.6, 1, and 2 under the assumption of one-way coupling using the Eulerian-Lagrangian method; two-way coupling is addressed in Part II. Analysis of interphase momentum transfer was performed in the Eulerian frame of reference by looking at the balance of fluid-phase mean momentum, mean kinetic energy, modal kinetic energy, and particle-phase mean momentum. The differences in the dominant mechanisms of vertical transport of streamwise momentum between the fluid and particle phases is clearly brought out. In the fluid phase, growth of the mixing layer is due to energy transfer from the mean flow to the unstable Kelvin-Helmholtz modes, and transport of mean momentum by these modes. In contrast, in the particle phase, the primary mechanism of vertical transport of streamwise momentum is convection due to the mean vertical velocity induced by the centrifuging of particles by the spanwise Kelvin-Helmholtz vortices. Although the drag force and the particle-phase modal stress play an important role in the early stages of the evolution of the mixing layer, their role is shown to decrease during the pairing process. After pairing, the particle-phase mean streamwise momentum balance is accounted for by the convection and drag force term. The particle-phase modal stress term is shown to be strongly connected to the fluid phase modal stress with a Stokes-number-dependent time lag in its evolution.

  5. 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.

  6. 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.

  7. Mitral Valve Disease

    MedlinePlus

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

  8. 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.

  9. Magnetically operated check valve

    NASA Astrophysics Data System (ADS)

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

    1994-06-01

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

  10. 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.

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

    PubMed Central

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

  12. 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.

  13. Hydrodynamic Performance of the Medtronic CoreValve and the Edwards SAPIEN XT Transcatheter Heart Valve in Surgical Bioprostheses: An In Vitro Valve-in-Valve Model.

    PubMed

    Sedaghat, Alexander; Sinning, Jan-Malte; Utzenrath, Marc; Ghalati, Pejman Farhadi; Schmitz, Christoph; Werner, Nikos; Nickenig, Georg; Grube, Eberhard; Ensminger, Stephan; Steinseifer, Ulrich; Kuetting, Maximilian

    2016-01-01

    Valve-in-valve transcatheter aortic valve replacement (TAVR) is becoming a valuable option with promising clinical results in failed bioprosthetic heart valves. Sizing recommendations are based on size compatibility rather than on broad clinical data, in vitro measurements, or biomechanical evidence. The hemodynamic performance of transcatheter heart valves within degenerated surgical heart valves is unknown. We evaluated the in vitro hydrodynamic performance of two commercially available transcatheter heart valves (Medtronic CoreValve [Medtronic, Minneapolis, MN] and Edwards SAPIEN XT [Edwards Lifesciences, Irvine, CA]) in two different bioprosthetic aortic valves (Edwards Perimount [Edwards Lifesciences] and St. Jude Trifecta [St. Jude Medical, St. Paul, MN]). Within the Edwards Perimount (23 mm) prosthesis, pressure gradients were higher for the SAPIEN XT compared with the CoreValve (11.2 ± 0.1 mm Hg versus 10.1 ± 0.1 mm Hg, p < 0.01), whereas effective orifice area (1.99 ± 0.01 cm(2) versus 1.80 ± 0.01 cm(2), p < 0.01) and total paravalvular leakage (9.0% ± 1.0% versus 5.4% ± 1.3%, p < 0.01) were increased when using the CoreValve. Similarly, measurements in the St. Jude Trifecta revealed higher transvalvular pressure gradients (13.0 ± 0.2 mm Hg versus 10.9 ± 0.3 mm Hg, p < 0.01) and lower effective orifice area for the SAPIEN XT compared with the CoreValve. However, total relative regurgitation was higher with SAPIEN XT as compared with the CoreValve in St. Jude Trifecta prostheses (11.2% ± 1.4% versus 8.3% ± 0.9%, p < 0.01). Both transcatheter heart valve prostheses performed well in the described valve-in-valve settings. Hydrodynamic results were in line with the International Organization for Standardization standards for all configurations. The observed differences indicate a necessity for preclinical valve-in-valve tests in addition to clinical long-term data about longevity. Copyright © 2016 The Society of Thoracic Surgeons. Published by

  14. Spectral analysis of one-way and two-way downscaling applications for a tidally driven coastal ocean forecasting system

    NASA Astrophysics Data System (ADS)

    Solano, Miguel; Gonzalez, Juan; Canals, Miguel; Capella, Jorge; Morell, Julio; Leonardi, Stefano

    2017-04-01

    ways: 1) using Rich Pawlowicz's t_tide package (classic harmonic analysis), 2) with traditional band-pass filters (e.g. Lanczos) and 3) using Proper Orthogonal Decomposition. The tide filtering approach shows great improvement in the high frequency response of tidal motions at the open boundaries. Results are validated with NOAA tide gauges, Acoustic Doppler Current Profilers, High Frequency Radars (6km and 2km resolution). A floating drifter experiment is performed in coastal zones, in which 12 drifters were deployed at different coastal zones and tracked for several days. The results show an improvement of the forecast skill with the proper implementation of the tide filtering approach by adjusting the nudging time scales and adequately removing the tidal signals. Significant improvement is found in the tracking skill of the floating drifters for the one-way grid and the two-way nested application also shows some improvement over the offline downscaling approach at higher resolutions.

  15. Early Mission Orbit Determination Error Analysis Results for Low-Earth Orbiting Missions using TDRSS Differenced One-way Doppler Tracking Data

    NASA Technical Reports Server (NTRS)

    Marr, Greg C.

    2003-01-01

    Differencing multiple, simultaneous Tracking and Data Relay Satellite System (TDRSS) one-way Doppler passes can yield metric tracking data usable for orbit determination for (low-cost) spacecraft which do not have TDRSS transponders or local oscillators stable enough to allow the one-way TDRSS Doppler tracking data to be used for early mission orbit determination. Orbit determination error analysis results are provided for low Earth orbiting spacecraft for various early mission tracking scenarios.

  16. Microfluidic sieve valves

    DOEpatents

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

    2015-01-13

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

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Double valve Implantation

    PubMed Central

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

    1991-01-01

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

  2. 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.

  3. Throttle valve control device

    SciTech Connect

    Nishida, M.; Katashiba, H.

    1988-03-01

    This patent describes a valve control device which comprises: a valve shaft for operating a throttle valve; a differential gear device having first and second drive gears, for driving the valve shaft; first and second electronic control actuators for rotating the first and second drive gear, respectively; and a sensor for detecting the degree of opening of the throttle valve, so that the operation of the throttle valve is controlled by the electronic control actuators while the degree of opening of the throttle valve is being detected.

  4. 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.

  5. 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.

  6. 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.

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

    PubMed Central

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

    2016-01-01

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

  8. Heart valve surgery - series (image)

    MedlinePlus

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

  9. 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.

  10. Magnetically operated check valve

    NASA Astrophysics Data System (ADS)

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

    1993-03-01

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

  11. Prosthetic Valve Dysfunction 35 Years after Mitral Valve Replacement with a Starr-Edwards Caged-disc Valve.

    PubMed

    Yokokawa, Tetsuro; Ohara, Takahiro; Takashio, Seiji; Sakamoto, Mari; Wada, Yuko; Nakamura, Kenji; Takahama, Hiroyuki; Amaki, Makoto; Hasegawa, Takuya; Sugano, Yasuo; Kanzaki, Hideaki; Yasuda, Satoshi; Ogawa, Hisao; Fujita, Tomoyuki; Kobayashi, Junjiro; Okamoto, Yoko; Matsuyama, Taka-Aki; Ishibashi-Ueda, Hatsue; Anzai, Toshihisa

    2016-01-01

    A 49-year-old man was admitted to our hospital with a chief complaint of dyspnea. He had a history of mitral valve replacement (MVR) with a Starr-Edwards (SE) caged-disc valve at the age of 14. Echocardiography revealed elevated trans-valvular pressure gradient of the mitral prosthetic valve with neither disk motion abnormality nor abnormal structure. Catheterization confirmed an elevation of the mean diastolic gradient of the mitral valve to 12.3 mmHg. Re-MVR was performed, and abnormal tissue attached to the cage of the valve and proliferating beneath the valve was observed. Histologic examination revealed them as fibrinous tissue and mild pannus proliferation, respectively. This rare case report focuses on long-term follow-up and the complication of a SE caged-disc valve. A SE caged-disc valve may become stenotic, only detected with a trans-valvular pressure gradient without any disk motion abnormality or abnormal structure during a prolonged follow-up period.

  12. Lubricator valve apparatus

    SciTech Connect

    Brooks, R. T.

    1984-10-16

    A lubricator valve assembly comprises a reciprocably rotatable ball valve which is operated between open and closed positions solely through the selective application of control pressures and/or tubing pressure above the valve to a double acting sleeve type actuating piston. One end of the actuating piston has a valving piston formed thereon which cooperates with a seal bore in the housing to effect the opening or closing of a bypass fluid passage extending from a region below the ball valve to a region above the ball valve. Such valving piston also functions as part of a lost motion connection between the actuating sleeve piston and a reciprocable actuator for rotating the ball valve. In opening the ball valve, the valving piston first moves upwardly to establish a fluid bypass around the closed ball valve and then establishes contact with the actuator to rotate the ball valve to an open position. The same fluid bypass may be utilized to pump through fluid around the closed ball valve by applying fluid pressure above the ball valve. Improved sealing elements for the ball valve are also provided.

  13. Mitral valve aneurysm associated with aortic valve endocarditis and regurgitation.

    PubMed

    Raval, Amish N; Menkis, Alan H; Boughner, Derek R

    2002-01-01

    Mitral valve aneurysms are rare complications occurring most commonly in association with aortic valve infective endocarditis. [Decroly 1989, Chua 1990, Northridge 1991, Karalis 1992, Roguin 1996, Mollod 1997, Vilacosta 1997, Cai 1999, Vilacosta 1999, Teskey 1999, Chan 2000, Goh 2000, Marcos- Alberca 2000] While the mechanism of the development of this lesion is unclear, complications such as perforation can occur and lead to significant mitral regurgitation. [Decroly 1989, Karalis 1992, Teskey 1999, Vilacosta 1999]; The case of a 69-year-old male with Streptococcus Sanguis aortic valve endocarditis and associated anterior mitral leaflet aneurysm is presented. Following surgery, tissue pathology of the excised lesion revealed myxomatous degeneration and no active endocarditis or inflammatory cells. This may add support to the hypothesis that physical stress due to severe aortic insufficiency and structural weakening, without infection of the anterior mitral leaflet, can lead to the development of this lesion.

  14. More than one way to splice an RNA: branching without a bulge and splicing without branching in group II introns.

    PubMed Central

    Chu, V T; Liu, Q; Podar, M; Perlman, P S; Pyle, A M

    1998-01-01

    Domain 6 (D6) of group II introns contains a bulged adenosine that serves as the branch-site during self-splicing. In addition to this adenosine, other structural features in D6 are likely to contribute to the efficiency of branching. To understand their role in promoting self-splicing, the branch-site and surrounding nucleotides were mutagenized. Detailed kinetic analysis on the self-splicing efficiency of the mutants revealed several interesting features. First, elimination of the branch-site does not preclude efficient splicing, which takes place instead through a hydrolytic first step. Second, pairing of the branch-site does not eliminate branching, particularly if the adenosine is involved in a mispair. Third, the G-U pairs that often surround group II intron branch-points contribute to the efficiency of branching. These results suggest that there is a strong driving force for promoting self-splicing by group II introns, which employ a versatile set of different mechanisms for ensuring that splicing is successful. In addition, the behavior of these mutants indicates that a bulged adenosine per se is not the important determinant for branch-site recognition in group II introns. Rather, the data suggest that the branch-site adenosine is recognized as a flipped base, a conformation that can be promoted by a variety of different substructures in RNA and DNA. PMID:9769094

  15. Cosmic background explorer (COBE) navigation with TDRSS one-way return-link Doppler in the post-helium-venting phase

    NASA Astrophysics Data System (ADS)

    Nemesure, M.; Dunham, J.; Maher, M.; Teles, J.; Jackson, J.

    1991-10-01

    A navigation experiment was performed which establishes Ultra-Stable Oscillator (USO) frequency stabilized one way return link Doppler TDRSS tracking data as a feasible option for mission orbit determination support at the Goddard Space Center Flight Dynamics Facility. The study was conducted using both one way and two way Tracking and Data Relay Satellite System (TDRSS) tracking measurements for the Cosmic Background Explorer (COBE) spacecraft. Tracking data for a 4 week period immediately follow the depletion of the helium supply was used. The study showed that, for both definitive orbit solution and short term orbit prediction (up to 4 weeks), orbit determination results based on one way return link Doppler tracking measurements are comparable to orbit determination results based on two way range and two way Doppler tracking measurements.

  16. Cosmic background explorer (COBE) navigation with TDRSS one-way return-link Doppler in the post-helium-venting phase

    NASA Technical Reports Server (NTRS)

    Nemesure, M.; Dunham, J.; Maher, M.; Teles, J.; Jackson, J.

    1991-01-01

    A navigation experiment was performed which establishes Ultra-Stable Oscillator (USO) frequency stabilized one way return link Doppler TDRSS tracking data as a feasible option for mission orbit determination support at the Goddard Space Center Flight Dynamics Facility. The study was conducted using both one way and two way Tracking and Data Relay Satellite System (TDRSS) tracking measurements for the Cosmic Background Explorer (COBE) spacecraft. Tracking data for a 4 week period immediately follow the depletion of the helium supply was used. The study showed that, for both definitive orbit solution and short term orbit prediction (up to 4 weeks), orbit determination results based on one way return link Doppler tracking measurements are comparable to orbit determination results based on two way range and two way Doppler tracking measurements.

  17. Adaptations of protein structure and function to temperature: there is more than one way to 'skin a cat'.

    PubMed

    Fields, Peter A; Dong, Yunwei; Meng, Xianliang; Somero, George N

    2015-06-01

    Sensitivity to temperature helps determine the success of organisms in all habitats, and is caused by the susceptibility of biochemical processes, including enzyme function, to temperature change. A series of studies using two structurally and catalytically related enzymes, A4-lactate dehydrogenase (A4-LDH) and cytosolic malate dehydrogenase (cMDH) have been especially valuable in determining the functional attributes of enzymes most sensitive to temperature, and identifying amino acid substitutions that lead to changes in those attributes. The results of these efforts indicate that ligand binding affinity and catalytic rate are key targets during temperature adaptation: ligand affinity decreases during cold adaptation to allow more rapid catalysis. Structural changes causing these functional shifts often comprise only a single amino acid substitution in an enzyme subunit containing approximately 330 residues; they occur on the surface of the protein in or near regions of the enzyme that move during catalysis, but not in the active site; and they decrease stability in cold-adapted orthologs by altering intra-molecular hydrogen bonding patterns or interactions with the solvent. Despite these structure-function insights, we currently are unable to predict a priori how a particular substitution alters enzyme function in relation to temperature. A predictive ability of this nature might allow a proteome-wide survey of adaptation to temperature and reveal what fraction of the proteome may need to adapt to temperature changes of the order predicted by global warming models. Approaches employing algorithms that calculate changes in protein stability in response to a mutation have the potential to help predict temperature adaptation in enzymes; however, using examples of temperature-adaptive mutations in A4-LDH and cMDH, we find that the algorithms we tested currently lack the sensitivity to detect the small changes in flexibility that are central to enzyme adaptation to

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Transcatheter aortic valve implantation.

    PubMed

    Oliemy, Ahmed; Al-Attar, Nawwar

    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.

  3. 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 Astrophysics Data System (ADS)

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

    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.

  4. Rare Case of Unileaflet Mitral Valve.

    PubMed

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

    2016-06-01

    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.

  5. 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

  6. 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.

  7. Valve mechanism having variable valve timing

    SciTech Connect

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

    1986-04-08

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

  8. 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.

  9. Mud separator valve apparatus

    SciTech Connect

    Schneider, S.J.

    1981-12-08

    An automatic cleaning system is provided for a mud separator apparatus. Water and mud inputs to a mud pump feeding the separator are respectively controlled by two butterfly valves ganged for cooperation, and operated by a single valve actuator motor. When the mud separator is shut off, a time delay relay is actuated which keeps the mud separator rotor motor on line during a predetermined flush cycle. The valve actuator opens the water valve, and closes the mud valve, permitting the separator to be flushed with water. Activating the start button returns the valve actuator to the position in which the mud valve is open and the water valve is closed, thereby returning the apparatus to the mud separation cycle.

  10. 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.

  11. Problem: Heart Valve Regurgitation

    MedlinePlus

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

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Stemless Ball Valve

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

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

  17. A case of SAPIEN XT valve fallen into left ventricle during valve-in-valve transcatheter aortic valve implantation.

    PubMed

    Koizumi, Shigeki; Ehara, Natsuhiko; Nishiya, Kenta; Koyama, Tadaaki

    2017-06-24

    Late transcatheter heart valve embolization is a rare but life-threatening complication of transcatheter aortic valve implantation. Surgical intervention is performed for most cases, but some cases were treated by valve-in-valve transcatheter aortic valve implantation. We describe a patient in whom a 29-mm Edwards SAPIEN XT valve migrated into the left ventricular outflow tract 41 days after the initial implantation. We tried to perform valve-in-valve transcatheter aortic valve implantation using a transfemoral approach. As soon as the second transcatheter heart valve touched the first implanted valve, it fell into the left ventricle. Immediate surgical intervention was required. The first valve was removed, and surgical aortic valve replacement was successfully performed. In conclusion, we should choose surgical aortic valve replacement for late transcatheter heart valve embolization. Even if we need to treat by catheter intervention, transapical approach may be better.

  18. Regional structure-function relationships in mouse aortic valve tissue

    PubMed Central

    Krishnamurthy, Varun K.; Guilak, Farshid; Narmoneva, Daria A.; Hinton, Robert B.

    2010-01-01

    Site-specific biomechanical properties of the aortic valve play an important role in native valve function, and alterations in these properties may reflect mechanisms of degeneration and disease. Small animals such as targeted mutagenesis mice provide a powerful approach to model human valve disease pathogenesis; however, physical mechanical testing in small animals is limited by valve tissue size. Aortic valves are comprised of highly organized extracellular matrix compartmentalized in cusp and annulus regions, which have different functions. The objective of this study was to measure regional mechanical properties of mouse aortic valve tissue using a modified micropipette aspiration technique. Aortic valves were isolated from juvenile, adult and aged adult C57BL/6 wild type mice. Tissue tensile stiffness was determined for annulus and cusp regions using a half-space punch model. Stiffness for the annulus region was significantly higher compared to the cusp region at all stages. Further, aged adult valve tissue had decreased stiffness in both the cusp and annulus. Quantitative histochemical analysis revealed a collagen-rich annulus and a proteoglycan-rich cusp at all stages. In aged adult valves, there was proteoglycan infiltration of the annulus hinge, consistent with observed mechanical differences over time. These findings indicate that valve tissue biomechanical properties vary in wild type mice in a region-specific and age-related manner. The micropipette aspiration technique provides a promising approach for studies of valve structure and function in small animal models, such as transgenic mouse models of valve disease. PMID:20863504

  19. 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.

  20. Problem: Mitral Valve Regurgitation

    MedlinePlus

    ... Stroke Vascular Health Peripheral Artery Disease Venous Thromboembolism Aortic Aneurysm More Problem: Mitral Valve Regurgitation Updated:Sep 21,2016 What is mitral valve ... blood flows from the ventricle through the aortic valve — as it should — and some blood flows ...

  1. 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.

  2. Liquid rocket valve assemblies

    NASA Technical Reports Server (NTRS)

    1973-01-01

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

  3. Well safety valve

    SciTech Connect

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

    1984-07-24

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

  4. Mitral Valve Prolapse

    PubMed Central

    Rosser, Walter W.

    1992-01-01

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

  5. Double-Poppet Valve

    NASA Technical Reports Server (NTRS)

    Huber, W. C.

    1984-01-01

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

  6. Disk Valve For Cryogenics

    NASA Technical Reports Server (NTRS)

    Calhoun, Richard B.

    1993-01-01

    Lightweight disk valve designed to have dimensions and capabilities similar to those of valve described in "Lightweight Right-Angle Valve For Cryogenics" (MSC-21889). Simple unit remains leaktight over wide range of pressures and temperatures without need for manual readjustment of packing gland. Weighs less than 60 g and made relatively inexpensively from some commercial and few simple custom-machined components.

  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. 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 ...

  9. Pulmonary Valve Stenosis

    MedlinePlus

    ... or valve or replaces the valve with an artificial valve. Repairs to other congenital heart defects can be made during the surgery, as well. There's a slight risk of bleeding, infection or blood clots associated with the surgery. While there's little ...

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

    PubMed

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

    2017-02-15

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

  11. How Is Mitral Valve Prolapse Treated?

    MedlinePlus

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

  12. Mitral Valve Annuloplasty

    PubMed Central

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

    2012-01-01

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

  13. 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.

  14. 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.

  15. 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

  16. 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.

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

    PubMed

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

    2017-07-01

    Valve-in-valve (VIV) transcatheter aortic valve replacement (TAVR) may be less effective in small surgical valves because of patient/prosthesis mismatch. Bioprosthetic valve fracture (BVF) using a high-pressure balloon can be performed to facilitate VIV TAVR. We report data from 20 consecutive clinical cases in which BVF was successfully performed before or after VIV TAVR by inflation of a high-pressure balloon positioned across the valve ring during rapid ventricular pacing. Hemodynamic measurements and calculation of the valve effective orifice area were performed at baseline, immediately after VIV TAVR, and after BVF. BVF was successfully performed in 20 patients undergoing VIV TAVR with balloon-expandable (n=8) or self-expanding (n=12) transcatheter valves in Mitroflow, Carpentier-Edwards Perimount, Magna and Magna Ease, Biocor Epic and Biocor Epic Supra, and Mosaic surgical valves. Successful fracture was noted fluoroscopically when the waist of the balloon released and by a sudden drop in inflation pressure, often accompanied by an audible snap. BVF resulted in a reduction in the mean transvalvular gradient (from 20.5±7.4 to 6.7±3.7 mm Hg, P<0.001) and an increase in valve effective orifice area (from 1.0±0.4 to 1.8±0.6 cm(2), P<0.001). No procedural complications were reported. BVF can be performed safely in small surgical valves to facilitate VIV TAVR with either balloon-expandable or self-expanding transcatheter valves and results in reduced residual transvalvular gradients and increased valve effective orifice area. © 2017 American Heart Association, Inc.

  18. Valve selection in aortic valve endocarditis

    PubMed Central

    Zubrytska, Yana

    2016-01-01

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

  19. Guide to prosthetic cardiac valves

    SciTech Connect

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

    1985-01-01

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

  20. 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

  1. 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.

  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. Cryogenic Cam Butterfly Valve

    NASA Technical Reports Server (NTRS)

    McCormack, Kenneth J. (Inventor)

    2016-01-01

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

  4. Minimally invasive valve surgery.

    PubMed

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

    2007-01-01

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

  5. JenaValve.

    PubMed

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

    2012-09-01

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

  6. Computational analysis of an aortic valve jet

    NASA Astrophysics Data System (ADS)

    Shadden, Shawn C.; Astorino, Matteo; Gerbeau, Jean-Frédéric

    2009-11-01

    In this work we employ a coupled FSI scheme using an immersed boundary method to simulate flow through a realistic deformable, 3D aortic valve model. This data was used to compute Lagrangian coherent structures, which revealed flow separation from the valve leaflets during systole, and correspondingly, the boundary between the jet of ejected fluid and the regions of separated, recirculating flow. Advantages of computing LCS in multi-dimensional FSI models of the aortic valve are twofold. For one, the quality and effectiveness of existing clinical indices used to measure aortic jet size can be tested by taking advantage of the accurate measure of the jet area derived from LCS. Secondly, as an ultimate goal, a reliable computational framework for the assessment of the aortic valve stenosis could be developed.

  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.

  8. 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.

  9. One-way quantum computing with arbitrarily large time-frequency continuous-variable cluster states from a single optical parametric oscillator

    NASA Astrophysics Data System (ADS)

    Alexander, Rafael N.; Wang, Pei; Sridhar, Niranjan; Chen, Moran; Pfister, Olivier; Menicucci, Nicolas C.

    2016-09-01

    One-way quantum computing is experimentally appealing because it requires only local measurements on an entangled resource called a cluster state. Record-size, but nonuniversal, continuous-variable cluster states were recently demonstrated separately in the time and frequency domains. We propose to combine these approaches into a scalable architecture in which a single optical parametric oscillator and simple interferometer entangle up to (3 ×103 frequencies) × (unlimited number of temporal modes) into a computationally universal continuous-variable cluster state. We introduce a generalized measurement protocol to enable improved computational performance on this entanglement resource.

  10. Generation of high-fidelity four-photon cluster state and quantum-domain demonstration of one-way quantum computing.

    PubMed

    Tokunaga, Yuuki; Kuwashiro, Shin; Yamamoto, Takashi; Koashi, Masato; Imoto, Nobuyuki

    2008-05-30

    We experimentally demonstrate a simple scheme for generating a four-photon entangled cluster state with fidelity over 0.860+/-0.015. We show that the fidelity is high enough to guarantee that the produced state is distinguished from Greenberger-Horne-Zeilinger, W, and Dicke types of genuine four-qubit entanglement. We also demonstrate basic operations of one-way quantum computing using the produced state and show that the output state fidelities surpass classical bounds, which indicates that the entanglement in the produced state essentially contributes to the quantum operation.

  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. Engine valve driving apparatus

    SciTech Connect

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

    1989-01-03

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

  13. 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.

  14. Magnetic Check Valve

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

  15. Transventricular mitral valve operations.

    PubMed

    Joseph Woo, Y; McCormick, Ryan C

    2011-10-01

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

  16. Modeling the Mitral Valve

    NASA Astrophysics Data System (ADS)

    Kaiser, Alexander

    2016-11-01

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

  17. A magnetically driven PDMS micropump with microball valves.

    PubMed

    McDonald, Scott; Pan, Tingrui; Ziaie, Babak

    2004-01-01

    We present a novel robust PDMS membrane micropump with two one-way microball valves for biomedical applications. The actuating membrane is driven by magnetic force of two miniature permanent magnets. The micropump consists of two PDMS layers, one holding the microball valves and actuating chamber and the second holding the top magnet and covering the chamber and microvalves. A simple approach is used to fabricate a high performance microball valve using an embedded Teflon/sup trade mark/ microtube. A small DC motor (6mm in diameter and 15mm in length) with two permanent magnetic discs (NdFeB) mounted on its shaft is used to actuate the membrane-mounted magnet. This configuration yields a large pumping rate with very low power consumption. Maximum pumping rate of 260muL/min was achieved at the input power of 21mW, the highest pumping rate reported in the literature for micropumps at such power consumption.

  18. The effect of nasal speaking valve on the speech under experimental velopharyngeal incompetence condition.

    PubMed

    Suwaki, M; Nanba, K; Ito, E; Kumakura, I; Minagi, S

    2008-05-01

    Velopharyngeal incompetence (VPI) is a contributing factor to speech disorders, frequently accompanying disorders, such as cleft palate, congenital paralysis of the soft palate, and cerebrovascular disease. For the treatment of these types of dysarthria, a Nasal Speaking Valve (NSV), which regulates nasal emission utilizing one-way valve, has been reported to be effective. As the unpleasantness while wearing the NSV was less than that with the conventional Palatal Lift Prosthesis, the NSV could be worn for a longer period of time. As NSV is inserted into the nostrils, this device could easily be provided for edentulous patients. This study aimed to evaluate the effect of NSV on experimentally induced VPI condition. Intelligibility of monosyllabic speech, intelligibility of conversational speech, nasalance score and acoustic analysis were used to evaluate the effect of NSV. Local infiltration anaesthesia was achieved to the area of levator veli palatini muscle and tensor veli palatine muscle of seven adult male subjects. In all subjects, remarkable suppression of the soft palate movement could be observed after the local infiltration anesthesia. Although the utterance supported by NSV under the experimentally induced VPI condition was less natural than the normal utterance, the intelligibility was markedly improved by the device. From the results of this study, the acoustic properties of NSV on the pure VPI condition, which was enabled by the newly established experimental induction, were revealed. This experimental model was also proved to provide a basis for the improvement in the treatment modalities for VPI.

  19. Late Paravalvular Aortic Regurgitation: Migration of the Valve or Late Recoil?

    PubMed

    Karimi, Ashkan; Pourafshar, Negiin; Park, Ki E; Choi, Calvin Y; Mogali, Kiran; Stinson, Wade W; Manning, Eddie W; Bavry, Anthony A

    2017-01-02

    A 79-year-old man underwent trans-catheter aortic valve replacement for symptomatic severe aortic stenosis with a 26-mm Edwards SAPIEN XT valve. Immediately after valve deployment there was moderate amount of paravalvular leak. Post-dilation was performed with an additional 2 cc of volume, and the paravalvular leak was reduced to trace. Nine months later, trans-thoracic echocardiography revealed moderate to severe paravalvular leak and possible aortic migration of the valve. The patient was brought back for the treatment of the paravalvular leak which was suspected to be due to valve migration. However, fluoroscopy and trans-esophageal echocardiography showed good valve position. Measurement of late valve recoil in the Coplanar view using cine-angiographic analysis software showed that the lower third of the valve had the greatest late recoil (-1.74 mm, 6.55%), which presumably accounted for the progression of the paravalvular leak. Valve-in-valve trans-catheter aortic valve replacement was performed with a 26-mm SAPIEN 3 valve and the paravalvular leak was reduced to trace. This case displays late recoil as a likely mechanism for development of paravalvular leak after SAPIEN XT valve implantation. Our case illustrates that late recoil needs to be systematically evaluated in future studies, especially when trans-catheter aortic valve replacement is being expanded to lower risk and younger patients for whom the longevity and long-term performance of these valves is of critical importance.

  20. Role of Channel Lysines and the “Push Through a One-Way Valve” Mechanism of the Viral DNA Packaging Motor

    PubMed Central

    Fang, Huaming; Jing, Peng; Haque, Farzin; Guo, Peixuan

    2012-01-01

    Linear double-stranded DNA (dsDNA) viruses package their genomes into preformed protein shells via nanomotors using ATP as an energy source. The central hub of the bacteriophage ϕ29 DNA-packaging motor contains a 3.6-nm channel for dsDNA to enter during packaging and to exit during infection. The negatively charged interior channel wall is decorated with a total of 48 positively charged lysine residues displayed as four 12-lysine rings from the 12 gp10 subunits that enclose the channel. The standard notion derived from many models is that these uniquely arranged, positively charged rings play active roles in DNA translocation through the channel. In this study, we tested this prevailing view by examining the effect of mutating these basic lysines to alanines, and assessing the impact of altering the pH environment. Unexpectedly, mutating these basic lysine residues or changing the pH to 4 or 10, which could alter the charge of lysines, did not measurably impair DNA translocation or affect the one-way traffic property of the channel. The results support our recent findings regarding the dsDNA packaging mechanism known as the “push through a one-way valve”. PMID:22225806

  1. 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

  2. Terahertz polarization converter and one-way transmission based on double-layer magneto-plasmonics of magnetized InSb.

    PubMed

    Fan, Fei; Xu, Shi-Tong; Wang, Xiang-Hui; Chang, Sheng-Jiang

    2016-11-14

    In this work, we investigate the nonreciprocal circular dichroism for terahertz (THz) waves in magnetized InSb by the theoretical calculation and numerical simulation, which indicates that longitudinally magnetized InSb can be applied to the circular polarizer and nonreciprocal one-way transmission for the circular polarization THz waves. Furthermore, we propose a double-layer magnetoplasmonics based on the longitudinally magnetized InSb, and find two MO enhancement mechanisms in this device: the magneto surface plasmon resonance on the InSb-metal surface and Fabry-Pérot resonances between two orthogonal metallic gratings. These two resonance mechanisms enlarge the MO polarization rotation and greatly reduce the external magnetic field below 0.1T. The one-way transmission and perfect linear polarization conversion can be realized over 70dB, of which the transmittance can be modulated from 0 to 80% when the weak magnetic field changes from 0 to 0.1T under the low temperature around 200K. This magnetoplasmonic device has broad potential as a THz isolator, modulator, polarization convertor, and filter in the THz application systems.

  3. Improved one-way hash chain and revocation polynomial-based self-healing group key distribution schemes in resource-constrained wireless networks.

    PubMed

    Chen, Huifang; Xie, Lei

    2014-12-18

    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.

  4. PETOOL: MATLAB-based one-way and two-way split-step parabolic equation tool for radiowave propagation over variable terrain

    NASA Astrophysics Data System (ADS)

    Ozgun, Ozlem; Apaydin, Gökhan; Kuzuoglu, Mustafa; Sevgi, Levent

    2011-12-01

    A MATLAB-based one-way and two-way split-step parabolic equation software tool (PETOOL) has been developed with a user-friendly graphical user interface (GUI) for the analysis and visualization of radio-wave propagation over variable terrain and through homogeneous and inhomogeneous atmosphere. The tool has a unique feature over existing one-way parabolic equation (PE)-based codes, because it utilizes the two-way split-step parabolic equation (SSPE) approach with wide-angle propagator, which is a recursive forward-backward algorithm to incorporate both forward and backward waves into the solution in the presence of variable terrain. First, the formulation of the classical one-way SSPE and the relatively-novel two-way SSPE is presented, with particular emphasis on their capabilities and the limitations. Next, the structure and the GUI capabilities of the PETOOL software tool are discussed in detail. The calibration of PETOOL is performed and demonstrated via analytical comparisons and/or representative canonical tests performed against the Geometric Optic (GO) + Uniform Theory of Diffraction (UTD). The tool can be used for research and/or educational purposes to investigate the effects of a variety of user-defined terrain and range-dependent refractivity profiles in electromagnetic wave propagation. Program summaryProgram title: PETOOL (Parabolic Equation Toolbox) Catalogue identifier: AEJS_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEJS_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 143 349 No. of bytes in distributed program, including test data, etc.: 23 280 251 Distribution format: tar.gz Programming language: MATLAB (MathWorks Inc.) 2010a. Partial Differential Toolbox and Curve Fitting Toolbox required Computer: PC Operating system: Windows XP and

  5. 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.

  6. Understanding Heart Valve Problems and Causes

    MedlinePlus

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

  7. 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 ...

  8. Valve mechanisms for at least two simultaneously actuable valves

    SciTech Connect

    Heimburg, F.

    1989-02-21

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

  9. Inhibitory role of Notch1 in calcific aortic valve disease.

    PubMed

    Acharya, Asha; Hans, Chetan P; Koenig, Sara N; Nichols, Haley A; Galindo, Cristi L; Garner, Harold R; Merrill, Walter H; Hinton, Robert B; Garg, Vidu

    2011-01-01

    Aortic valve calcification is the most common form of valvular heart disease, but the mechanisms of calcific aortic valve disease (CAVD) are unknown. NOTCH1 mutations are associated with aortic valve malformations and adult-onset calcification in families with inherited disease. The Notch signaling pathway is critical for multiple cell differentiation processes, but its role in the development of CAVD is not well understood. The aim of this study was to investigate the molecular changes that occur with inhibition of Notch signaling in the aortic valve. Notch signaling pathway members are expressed in adult aortic valve cusps, and examination of diseased human aortic valves revealed decreased expression of NOTCH1 in areas of calcium deposition. To identify downstream mediators of Notch1, we examined gene expression changes that occur with chemical inhibition of Notch signaling in rat aortic valve interstitial cells (AVICs). We found significant downregulation of Sox9 along with several cartilage-specific genes that were direct targets of the transcription factor, Sox9. Loss of Sox9 expression has been published to be associated with aortic valve calcification. Utilizing an in vitro porcine aortic valve calcification model system, inhibition of Notch activity resulted in accelerated calcification while stimulation of Notch signaling attenuated the calcific process. Finally, the addition of Sox9 was able to prevent the calcification of porcine AVICs that occurs with Notch inhibition. In conclusion, loss of Notch signaling contributes to aortic valve calcification via a Sox9-dependent mechanism.

  10. Coanda effect in valves

    NASA Astrophysics Data System (ADS)

    Uruba, Václav; Procházka, Pavel; Skála, Vladislav

    2016-11-01

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

  11. 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.

  12. 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.

  13. Minimally invasive valve surgery.

    PubMed

    Woo, Y Joseph

    2009-08-01

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

  14. Valve for abrasive material

    SciTech Connect

    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.

  15. 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.

  16. Cavitation dynamics of mechanical heart valve prostheses.

    PubMed

    Lee, C S; Chandran, K B; Chen, L D

    1994-10-01

    Nine different mechanical mitral heart valves were chosen in order to study cavitation dynamics in detail in an in vitro flow system simulating a single event of mitral valve closure. The transvalvular pressure (ventricular minus atrial pressure) rise rate averaged during the valve closing period was used as an index of the loading rate. A series of photographs in the vicinity of the inflow surface of the valve were attempted during the bubble appearance period using a stroboscopic visualization technique. The in vitro study revealed three sources of cavitation initiation in the design of the mechanical heart valves tested: stop (seat stop or seating lip), inflow strut, and clearance (gap formed between the occluder and the housing or between the two occluders in the closed position). Among these, the occluder stop design was the most critical to cavitation since all valves having the stop at the edge of the major orifice area showed a higher intensity of cavitation and threshold loading rates below the estimated normal physiological value. The analysis of bubble locations and dynamics led us to propose that the fluid squeezing effect between the occluder and the stop in the housing and the streamline contraction effect along the clearance are factors responsible for cavitation incipience.

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

    PubMed Central

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

    2017-01-01

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

  18. 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.

  19. 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)

  20. Boston Scientific Lotus valve.

    PubMed

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

    2012-09-01

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

  1. Nontraumatic avulsion of aortic valve commissure as a cause of acute aortic valve regurgitation

    PubMed Central

    Chang, Rei-Yeuh; Chen, Chien-Chang; Hsu, Wei-Pang; Hsiao, Pei-Ching; Tsai, Han-Lin; Hsiao, Ping-Gune; Wu, Jiann-Der; Guo, How-Ran

    2016-01-01

    Abstract Background: Avulsion of the aortic valve commissure as a cause of acute aortic valve regurgitation is mostly due to trauma, infective endocarditis, or ascending aortic dissection. Nontraumatic avulsion of the aortic valve commissure is very rare. We reviewed the literature and analyzed potential risk factors of nontraumatic avulsion. Case presentation: An 80-year-old male with hypertension was seen in the emergency department with acute onset dyspnea. Echocardiogram revealed left ventricular hypertrophy with adequate systolic function, prolapse of the noncoronary cusp, and incomplete coaptation of the right coronary and noncoronary cusps with severe aortic valve regurgitation. Surgery revealed an avulsion between the left coronary and noncoronary cusps. Histopathology examination of the aortic valve showed myxoid degeneration, fibrosis, and calcification. Examination of the ascending aorta revealed myxoid degeneration and fragmentation of elastic fibers. Aortic valve replacement was performed, and the patient was alive and well 4 years after surgery. A review of the literature showed that more than three-fourths of the similar cases occurred in males, and about half in patients with hypertension and those 60 years of age or older. Conclusions: In the case of acute aortic regurgitation without a history of trauma, infection, or valvotomy, when 2 prolapsed aortic cusps are observed by echocardiography in the absence of an intimal tear of the ascending aorta, an avulsion of the aortic commissure should be suspected, especially in males with hypertension who are 60 years of age or older. PMID:27749570

  2. Engine valve train system

    SciTech Connect

    Derringer, J.G.

    1986-12-09

    This patent describes a reciprocating internal combustion engine of the type having an engine block means defining at least one cylinder with an associate pair of ports, a valve located for axial movement in each of the ports with each valve normally biased to a valve closed position relative to its associate port. A rocker shaft support means is fixed to the engine block means, and a valve actuator is spaced from the valves and operable to effect reciprocation of the valves. The improvement described here comprises a rocker shaft pivotably supported by the rocker shaft support means, the rocker shaft having an axial passage adapted to be in continuous flow communication with the pressurized lubricant supply of the engine. It also includes first rocker arm pivotably supported on the rocker shaft in position for engagement with the valve actuator and with one of the valves and actuated in rocking movement whereby it can operate to effect opening and closing movement of one of the valves, and a second rocker arm pivotably supported on the rocker shaft next adjacent to the first rocker arm and operatively engaging the other one of the valves, the second rocker arm having a hydraulic cylinder means therein. A piston is sealingly journaled in the hydraulic cylinder means and located so as to permit engagement of the piston with the first rocker arm, the second rocker arm having a supply/drain passage means therein to the hydraulic cylinder means, and a drain passage which extends to the exterior of the second rocker arm and which is located in circumferentially spaced apart relationship to the supply/drain passage means.

  3. A fascial frustum valve for aortic valve replacement

    PubMed Central

    Yates, A. K.

    1971-01-01

    The promising qualities of autologous fascia lata in heart valve replacement have resulted in a search for improved methods of fascial heart valve manufacture. This paper describes a simply made and inserted and reliably competent unsupported fascial valve for aortic valve replacement. Images PMID:5576536

  4. Echocardiography in Transcatheter Aortic Valve Implantation and Mitral Valve Clip

    PubMed Central

    Luo, Huai

    2012-01-01

    Transcatheter aortic valve implantation and transcatheter mitral valve repair (MitraClip) procedures have been performed worldwide. In this paper, we review the use of two-dimensional and three-dimensional transesophageal echo for guiding transcatheter aortic valve replacement and mitral valve repair. PMID:23019387

  5. Cooperative effect of random and time-periodic coupling strength on synchronization transitions in one-way coupled neural system: mean field approach.

    PubMed

    Jiancheng, Shi; Min, Luo; Chusheng, Huang

    2017-08-01

    The cooperative effect of random coupling strength and time-periodic coupling strengh on synchronization transitions in one-way coupled neural system has been investigated by mean field approach. Results show that cooperative coupling strength (CCS) plays an active role for the enhancement of synchronization transitions. There exist an optimal frequency of CCS which makes the system display the best CCS-induced synchronization transitions, a critical frequency of CCS which can not further affect the CCS-induced synchronization transitions, and a critical amplitude of CCS which can not occur the CCS-induced synchronization transitions. Meanwhile, noise intensity plays a negative role for the CCS-induced synchronization transitions. Furthermore, it is found that the novel CCS amplitude-induced synchronization transitions and CCS frequency-induced synchronization transitions are found.

  6. More than one way to control hair growth: regulatory mechanisms in enterobacteria that affect fimbriae assembled by the chaperone/usher pathway.

    PubMed

    Clegg, Steven; Wilson, Janet; Johnson, Jeremiah

    2011-05-01

    Many gram-negative enterobacteria produce surface-associated fimbriae that facilitate attachment and adherence to eucaryotic cells and tissues. These organelles are believed to play an important role during infection by enabling bacteria to colonize specific niches within their hosts. One class of these fimbriae is assembled using a periplasmic chaperone and membrane-associated scaffolding protein that has been referred to as an usher because of its function in fimbrial biogenesis. The presence of multiple types of fimbriae assembled by the chaperone/usher pathway can be found both within a single bacterial species and also among different genera. One way of controlling fimbrial assembly in these bacteria is at the genetic level by positively or negatively regulating fimbrial gene expression. This minireview considers the mechanisms that have been described to control fimbrial gene expression and uses specific examples to demonstrate both unique and shared properties of such regulatory mechanisms.

  7. More than One Way To Control Hair Growth: Regulatory Mechanisms in Enterobacteria That Affect Fimbriae Assembled by the Chaperone/Usher Pathway▿

    PubMed Central

    Clegg, Steven; Wilson, Janet; Johnson, Jeremiah

    2011-01-01

    Many Gram-negative enterobacteria produce surface-associated fimbriae that facilitate attachment and adherence to eucaryotic cells and tissues. These organelles are believed to play an important role during infection by enabling bacteria to colonize specific niches within their hosts. One class of these fimbriae is assembled using a periplasmic chaperone and membrane-associated scaffolding protein that has been referred to as an usher because of its function in fimbrial biogenesis. The presence of multiple types of fimbriae assembled by the chaperone/usher pathway can be found both within a single bacterial species and also among different genera. One way of controlling fimbrial assembly in these bacteria is at the genetic level by positively or negatively regulating fimbrial gene expression. This minireview considers the mechanisms that have been described to control fimbrial gene expression and uses specific examples to demonstrate both unique and shared properties of such regulatory mechanisms. PMID:21398554

  8. 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

  9. 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.

  10. 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

  11. 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.

  12. Solar wind interaction with Mars Upper atmosphere: Results from the one-way coupling between the Multi-fluid MHD model and the M-TGCM model

    NASA Astrophysics Data System (ADS)

    Dong, C.; Bougher, S. W.; Ma, Y.; Toth, G.; Nagy, A. F.; Brain, D. A.; Najib, D.

    2012-12-01

    The study of the solar wind interaction with Mars upper atmosphere/ionosphere has triggered great interest in recent years. Among the large number of topics in this research area, the investigation of ion escape rates has become increasingly important due to its potential impact on the long-term evolution of Mars atmosphere (e.g., loss of water) over its history. In the present work, we adopt the 3D Mars neutral atmosphere profiles from the well-regarded Mars Thermospheric Global Circulation Model (M-TGCM) and one-way couple it with the 3D BATS-R-US Mars multi-fluid MHD model that solves separate momentum equations for each ion species. The M-TGCM model takes into account the effects of the solar cycle (solar minimum: F10.7=70 and solar maximum: F10.7=200 with equinox condition: Ls=0), allowing us to investigate the effects of the solar cycle on the Mars upper atmosphere ion escape by using a one-way coupling, i.e., the M-TGCM model outputs are used as inputs for the multi-fluid MHD model. A case for solar maximum with extremely high solar wind parameters is also investigated to estimate how high the escape flux can be for such an extreme case. Moreover, the ion escape flux along a satellite trajectory will be studied. This has the potential to provide predictions of ion escape rates for comparison to future data to be returned by the MAVEN mission (2012-2016). In order to make the code run more efficiently, we adopt a more appropriate grid structure compared to the one used previously. This new grid structure will benefit us to investigate the effects of some dynamic events (such as CME and dust storm) on the ion escape flux.

  13. Tailored One-Way and Two-Way Shape Memory Capabilities of Poly(ɛ-Caprolactone)-Based Systems for Biomedical Applications

    NASA Astrophysics Data System (ADS)

    Pandini, Stefano; Riccò, Theonis; Borboni, Alberto; Bodini, Ileana; Vetturi, David; Cambiaghi, Danilo; Toselli, Maurizio; Paderni, Katia; Messori, Massimo; Pilati, Francesco; Chiellini, Federica; Bartoli, Cristina

    2014-07-01

    This paper investigates the shape memory capabilities of semicrystalline networks, focusing the attention on poly(ɛ-caprolactone) (PCL) systems, a class of materials that allows to satisfy important requirements for their applications as biomedical devices, such as the good biocompatibility, the fast recovery of large "temporary" shape configurations, and the easy tailoring of the transformation temperatures. The materials were prepared with various crosslink densities and crosslinking methodologies; in particular, beside a thermal crosslinking based on reactive methacrylic end groups, a novel type of covalently crosslinked semicrystalline systems was prepared by a sol-gel approach from alkoxysilane-terminated PCL precursors, so as to avoid potentially toxic additives typically used for free-radical thermal curing. The materials were subjected to biological tests, to study their ability in sustaining cell adhesion and proliferation, and to thermal characterizations, to evaluate the possibility to tailor their melting and crystallization temperatures. The one-way shape memory (i.e., the possibility to set the material in a given configuration and to recover its pristine shape) and the two-way shape memory response (i.e., the triggered change between two distinguished shapes on the application of an on-off stimulus) were studied by applying optimized thermo-mechanical cyclic histories. The ability to fix the applied shape and to recover the original one on the application of heating (i.e., the one-way effect) was evaluated on tensile bars; further, to investigate a potential application as self-expandable stents, isothermal shape memory experiments were carried out also on tubular specimens, previously folded in a temporary compact configuration. The two-way response was studied through the application of a constant load and of a heating/cooling cycle from above melting to below the crystallization temperature, leading to a reversible elongation/contraction effect

  14. A novel solution to prosthetic valve dehiscence after aortic valve surgery in Behçet's disease.

    PubMed

    Jung, Yochun; Ahn, Byoung Hee; Lee, Kyo Seon; Jeong, In Seok; Kim, Kye Hun; Na, Kook Joo; Ryu, Sang-Wan; Oh, Sang Gi

    2017-03-01

    Prosthetic valve dehiscence after aortic valve surgery in Behçet's disease patients is common. We aimed to validate the usefulness of our new technique 'subannular endomyocardial implantation of valve prosthesis' designed to prevent prosthetic valve dehiscence. Subannular endomyocardial implantation of valve prosthesis involves suturing the sewing cuff of the valve prosthesis in the endomyocardium below the aortic annulus, which is based on the idea that annular tissue should be excluded from the suture line in Behçet's disease patients. Medical records of 7 patients in whom the new technique was performed between 2002 and 2014 were reviewed. Five men and two women were included (median age, 44 years). Aortic root replacement was performed in 6 cases, and aortic valve replacement in 1. No operative mortality occurred. Postoperatively, complete atrioventricular block developed in 3 cases, and permanent pacemakers were implanted in 2. No reoperation was performed for prosthetic valve dehiscence during the median 7.8-year follow-up. One late death occurred due to sudden cardiac arrest 8.4 years after surgery. One additional permanent pacemaker was implanted for complete atrioventricular block, which developed at 4.2 years postoperatively. The last echocardiography (median, 6.7 years after surgery) revealed no paravalvular leakages. Subannular endomyocardial implantation of valve prosthesis seems useful for preventing prosthetic valve dehiscence after aortic valve surgery for Behçet's disease. It poses a risk of complete atrioventricular block, but considering the high reoperation rate and mortality due to prosthetic valve dehiscence after conventional aortic valve surgery, this risk seems reasonable.

  15. 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.

  16. 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.

  17. Study of multiple cycles valves

    NASA Technical Reports Server (NTRS)

    Wichmann, H.

    1973-01-01

    A discussion is presented regarding valves which can be cycled repeatedly and are available from industry for application in the inlet system for the Pioneer Venus Probe mass spectrometer. Both solenoid type and latching type valves are considered. The study is divided into two principal areas: (1) preparation of a valve specification reflecting the requirements of the inlet system cyclic valves for the Pioneer Venus Probe mass spectrometer and the submittal of this specification to potential valve suppliers for their response and proposal; (2) preparation of a design layout of an optimum cyclic valve meeting all of the valve specification requirements.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

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

    PubMed

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

    2017-06-29

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

  3. Altered Hemodynamics in the Embryonic Heart Affects Outflow Valve Development

    PubMed Central

    Menon, Vinal; Eberth, John F.; Goodwin, Richard L.; Potts, Jay D.

    2016-01-01

    Cardiac valve structure and function are primarily determined during early development. Consequently, abnormally-formed heart valves are the most common type of congenital heart defects. Several adult valve diseases can be backtracked to abnormal valve development, making it imperative to completely understand the process and regulation of heart valve development. Epithelial-to-mesenchymal transition (EMT) plays an important role in the development of heart valves. Though hemodynamics is vital to valve development, its role in regulating EMT is still unknown. In this study, intracardiac hemodynamics were altered by constricting the outflow tract (OFT)/ventricle junction (OVJ) of HH16–17 (Hamilton and Hamburger (HH) Stage 16–17) chicken embryos, ex ovo for 24 h. The constriction created an increase in peak and time-averaged centerline velocity along the OFT without changes to volumetric flow or heart rate. Computational fluid dynamics was used to estimate the level of increased spatially-averaged wall shear stresses on the OFT cushion from AMIRA reconstructions. OFT constriction led to a significant decrease in OFT cushion volume and the number of invaded mesenchyme in the OFT cushion. qPCR analysis revealed altered mRNA expression of a representative panel of genes, vital to valve development, in the OFT cushions from banded hearts. This study indicates the importance of hemodynamics in valve development. PMID:26878022

  4. Transcatheter Pulmonary Valve Replacement by Hybrid Approach Using a Novel Polymeric Prosthetic Heart Valve: Proof of Concept in Sheep

    PubMed Central

    Xu, Tong-yi; Zhang, Zhi-gang; Li, Xin; Han, Lin; Xu, Zhi-yun

    2014-01-01

    Background Since 2000, transcatheter pulmonary valve replacement has steadily advanced. However, the available prosthetic valves are restricted to bioprosthesis which have defects like poor durability. Polymeric heart valve is thought as a promising alternative to bioprosthesis. In this study, we introduced a novel polymeric transcatheter pulmonary valve and evaluated its feasibility and safety in sheep by a hybrid approach. Methods We designed a novel polymeric trileaflet transcatheter pulmonary valve with a balloon-expandable stent, and the valve leaflets were made of 0.1-mm expanded polytetrafluoroethylene (ePTFE) coated with phosphorylcholine. We chose glutaraldehyde-treated bovine pericardium valves as control. Pulmonary valve stents were implanted in situ by a hybrid transapical approach in 10 healthy sheep (8 for polymeric valve and 2 for bovine pericardium valve), weighing an average of 22.5±2.0 kg. Angiography and cardiac catheter examination were performed after implantation to assess immediate valvular functionality. After 4-week follow-up, angiography, echocardiography, computed tomography, and cardiac catheter examination were used to assess early valvular function. One randomly selected sheep with polymeric valve was euthanized and the explanted valved stent was analyzed macroscopically and microscopically. Findings Implantation was successful in 9 sheep. Angiography at implantation showed all 9 prosthetic valves demonstrated orthotopic position and normal functionality. All 9 sheep survived at 4-week follow-up. Four-week follow-up revealed no evidence of valve stent dislocation or deformation and normal valvular and cardiac functionality. The cardiac catheter examination showed the peak-peak transvalvular pressure gradient of the polymeric valves was 11.9±5.0 mmHg, while that of two bovine pericardium valves were 11 and 17 mmHg. Gross morphology demonstrated good opening and closure characteristics. No thrombus or calcification was seen

  5. 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)

  6. Mitral valve regurgitation

    MedlinePlus

    ... your provider and dentist if you have a history of heart valve disease or congenital heart disease before treatment. Some people ... In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine . 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap ...

  7. Mitral Valve Prolapse

    MedlinePlus

    ... Peripheral Vascular Disease Rheumatic Fever Sick Sinus Syndrome Silent Ischemia Stroke Sudden Cardiac Arrest Valve Disease Vulnerable ... a stethoscope, your doctor may hear a "clicking" sound caused by the flapping of the leaflets. What ...

  8. 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)

  9. 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.

  10. 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.

  11. 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.

  12. THERMALLY OPERATED VAPOR VALVE

    DOEpatents

    Dorward, J.G. Jr.

    1959-02-10

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

  13. 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 ...

  14. Down hole safety valve for concentric completion

    SciTech Connect

    Geyelin, J.L.

    1987-01-01

    Gas lift is a widespread method of artificial lift. However, on wells where there is no provision for Side Pocket Mandrels one way to avoid a heavy work over, is to run a macaroni string inside the existing tubing; gas can be injected via the macaroni and the lifted fluid flowed through the tubing-macaroni annulus. On offshore wells, regulations or Company policy may impose the use of Surface Controlled Subsurface Safety Valve. This paper describes a new type of SC-SSV, run as an integral part of the macaroni string, which will close the macaroni string and the tubing-macaroni annulus. Associated equipment to set the SC-SSV in place and to seal the macaroni string system in the Christmas-tree is also covered in the paper. In addition, field experience on over 30 offshore wells equipped with such a system is related.

  15. 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.

  16. Liquid blocking check valve

    DOEpatents

    Merrill, John T.

    1984-01-01

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

  17. Bicuspid Aortic Valve

    DTIC Science & Technology

    2006-08-01

    Schnell E, Wollenek G, Maurer G, Baumgartner H, Lang IM. Mechanisms underlying aortic dilatation in congenital aortic valve malformation . Circulation...1999; 99(16):2138-2143. 10. Roberts CS, Roberts WC. Dissection of the aorta associated with congenital malformation of the aortic valve. J Am Coll... congenital heart defect, often diagnosed incidentally or as a consequence of an associated condition. Patients with this anomaly are at increased risk

  18. Cooling the two-dimensional short spherocylinder liquid to the tetratic phase: Heterogeneous dynamics with one-way coupling between rotational and translational hopping.

    PubMed

    Su, Yen-Shuo; I, Lin

    2015-07-01

    We numerically demonstrate the transition from the isotropic liquid to the tetratic phase with quasilong-range tetratic alignment order (i.e., with nearly parallel or perpendicular aligned rods), for the cold two-dimensional (2D) short spherocylinder system before crystallization and investigate the thermal assisted heterogeneous rotational and translational micromotions. Comparing with the 2D liquid of isotropic particles, spherocylinders introduce extra rotational degrees of freedom and destroy packing isotropy and the equivalence between rotational and translational motions. It is found that cooling leads to the stronger dynamical heterogeneity with more cooperative hopping and the stronger retardations of rotational hopping than translational hopping. Under topological constraints from nearly parallel and perpendicular rods of the tetratic phase, longitudinal and transverse translational hopping can occur without rotational hopping, but not the reverse. The empty space trailing a neighboring translational hopping patch is needed for triggering the patch rotational hopping with its translational motion into the empty space. It is the origin for the observed increasing separation of hopping time scales and the one-way coupling between rotational and translational hopping. Strips of longitudinally or transversely aligned rods can be ruptured and reconnected with neighboring strips through buckling, kink formation, and patch rotation, under the unbalanced torques or forces from their neighboring rods and thermal kicks.

  19. 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.

  20. 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.

  1. 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.

  2. Piston and valve assembly

    SciTech Connect

    Rolder, G. K.

    1985-10-01

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

  3. Engine valve train module

    SciTech Connect

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

    1988-01-26

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

  4. [Tricuspid valve dysplasia in fifteen dogs].

    PubMed

    Hoffmann, G; Amberger, C N; Seiler, G; Lombard, C W

    2000-05-01

    Clinical findings in fifteen dogs with tricuspid valve dysplasia are described. Thirteen dogs had loud systolic heart murmurs. Eleven of them hat a palpable precordial thrill over the same location. In 14 dogs, right heart enlargement was suspected on thoracic radiographs and electrocardiography. Right atrial dilation was seen echocardiographically in all dogs. Fourteen dogs had additional right ventricular dilatation, some with hypertrophy as well. Doppler echocardiography revealed tricuspid valve regurgitation. Seven dogs remained free of clinical symptoms to date. If symptoms of decompensation develop with tricuspid dysplasia, diuretics, ACE inhibitors and eventually positive inotrope drugs are indicated. Antiarrhythmic drugs may become necessary in cases of supraventricular tachyarrhythmias.

  5. Transcatheter treatment of tricuspid regurgitation by caval valve implantation--experimental evaluation of decellularized tissue valves in central venous position.

    PubMed

    Lauten, Alexander; Laube, Adrian; Schubert, Harald; Bischoff, Sabine; Nietzsche, Sandor; Horstkötter, Kim; Poudel-Bochmann, Bhawana; Franz, Marcus; Lichtenberg, Artur; Figulla, Hans R; Akhyari, Payam

    2015-01-01

    Caval valve implantation has been suggested for transcatheter treatment of severe tricuspid regurgitation (TR). Combining the interventional technique with the promising surgical experience with decellularized valves, we sought to evaluate the functional and structural outcome of decellularized pericardial tissue valves (dTVs) in the low-pressure venous circulation in a chronic model of TR. Sixteen pericardial tissue valves were heterotopically implanted in the inferior and superior vena cava in a sheep model (54-98 kg; median 74.5 kg, n = 8) of severe TR. The devices were assembled using self-expanding nitinol stents and bovine pericardia decellularized by a detergent-based protocol (group dTV; n = 8). Glutaraldehyde-fixed pericardial tissue valves served as control (GaTV, n = 8). After 6 months, device function and structural maturation were analyzed using echocardiographic, histologic, immunohistologic, and electron microscopic approaches. After implantation, cardiac output increased significantly from 3.7 ± 1.1 l/min to 4.8 ± 1.1 l/min (P < 0.05) and competent valve function was verified by angiography. At 6 months, angiographic and echocardiographic evaluation revealed moderate to severe regurgitation in all GaTV. In contrast, five of the eight dTVs functioned well with only minor regurgitation. In these animals, autopsy revealed preserved valve structure with tender leaflets without signs of thrombosis or calcification. Conversely, GaTV showed severe degeneration with large calcification areas. Microscopic and histologic analysis confirmed endothelial repopulation in both valve types. However, additional interstitial reseeding was observed in decellularized valves. In the venous circulation in severe TR, decellularized valves show superior functional performance compared to Ga-fixed tissue valves. Macroscopic and microscopic analyses suggest preserved structural integrity and advanced endothelial and interstitial repopulation with

  6. Isolated true parachute mitral valve in an asymptomatic elderly patient.

    PubMed

    Yamamoto, Tetsushi; Onishi, Tetsuari; Omar, Alaa Marbrouk Salem; Norisada, Kazuko; Tatsumi, Kazuhiro; Matsumoto, Kensuke; Hayashi, Nobuhide; Kinoshita, Shouhiro; Kawano, Seiji; Kawai, Hiroya; Hirata, Ken-Ichi; Kumagai, Shunichi

    2010-12-01

    We report the extremely rare case of a 73-year-old asymptomatic patient who has an isolated true parachute mitral valve (PMV). In the echocardiographic examination, the parasternal long-axis view showed a single papillary muscle. The short-axis view revealed the presence of a symmetric mitral valve orifice with all chordae attaching to a large anterolateral papillary muscle. Because detailed examination did not reveal the presence of other complications, this patient was diagnosed as an isolated true PMV.

  7. Pulsed holmium laser ablation of cardiac valves

    SciTech Connect

    Lilge, L.; Radtke, W.; Nishioka, N.S. )

    1989-01-01

    Ablation efficiency and residual thermal damage produced by pulsed holmium laser radiation were investigated in vitro for bovine mitral valves and human calcified and noncalcified cardiac valves. Low-OH quartz fibers (200 and 600 microns core diameter) were used in direct contact perpendicular to the specimen under saline or blood. Etch rate was measured with a linear motion transducer. Radiant exposure was varied from 0 to 3 kJ/cm{sup 2}. For 200-microns fibers, the energy of ablation was approximately 5 kJ/cm{sup 3} in noncalcified and 15 kJ/cm{sup 3} in calcified valves. Etch rates were dependent on mechanical tissue properties. Maximum etch rate at 1,000 J/cm{sup 2} was 1-2 mm/pulse at 3 Hz repetition rate. Microscopic examination revealed a zone of thermal damage extending 300 microns lateral into adjacent tissue. Thermal damage was independent of radiant exposure beyond twice threshold.

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

    PubMed

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

    2016-05-01

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

  9. Estimating Accurate Relative Spacecraft Angular Position from Deep Space Network Very Long Baseline Interferometry Phases Using X-Band Telemetry or Differential One-Way Ranging Tones

    NASA Astrophysics Data System (ADS)

    Bagri, D. S.; Majid, W. A.

    2008-02-01

    At present spacecraft angular position with the Deep Space Network (DSN) is determined using group delay estimates from very long baseline interferometry (VLBI) phase measurements employing differential one-way ranging (DOR) tones. Group delay measurements require high signal-to-noise ratio (SNR) to provide modest angular position accuracy. On the other hand, VLBI phases with modest SNR can be used to determine the position of a spacecraft with high accuracy, except for the interferometer interference fringe cycle ambiguity, which can be resolved using multiple baselines, requiring several antenna stations as is done, for example, using the Very Long Baseline Array (VLBA) (e.g, the VLBA has 10 antenna stations). As an alternative to this approach, here we propose estimating the position of a spacecraft to half-a-fringe-cycle accuracy using time variations between measured and calculated phases, using DSN VLBI baseline(s), as the Earth rotates (i.e., estimate position offset from the difference between observed and calculated phases for different spatial frequency (U,V) values). Combining the fringe location of the target with the phase information allows for estimate of spacecraft angular position to a high accuracy. One of the advantages of this scheme, in addition to the possibility of achieving a fraction of a nanoradian measurement accuracy using DSN antennas for VLBI, is that it is possible to use telemetry signals with at least a 4 to 8 Msamples/s data rate (bandwidth greater than about 8 to 16 MHz) to measure spacecraft angular position instead of using DOR tones, as is currently done. Using telemetry instead of DOR tones will eliminate the need for spacecraft coordination for angular position measurements and will minimize calibration errors due to instrumental dispersion effects.

  10. Multi-decadal scenario simulation over Korea using a one-way double-nested regional climate model system. Part 2: future climate projection (2021 2050)

    NASA Astrophysics Data System (ADS)

    Im, Eun-Soon; Ahn, Joong-Bae; Kwon, Won-Tae; Giorgi, Filippo

    2008-02-01

    An analysis of simulated future surface climate change over the southern half of Korean Peninsula using a RegCM3-based high-resolution one-way double-nested system is presented. Changes in mean climate as well as the frequency and intensity of extreme climate events are discussed for the 30-year-period of 2021 2050 with respect to the reference period of 1971 2000 based on the IPCC SRES B2 emission scenario. Warming in the range of 1 4°C is found throughout the analysis region and in all seasons. The warming is maximum in the higher latitudes of the South Korean Peninsula and in the cold season. A large reduction in snow depth is projected in response to the increase of winter minimum temperature induced by the greenhouse warming. The change in precipitation shows a distinct seasonal variation and a substantial regional variability. In particular, we find a large increase of wintertime precipitation over Korea, especially in the upslope side of major mountain systems. Summer precipitation increases over the northern part of South Korea and decreases over the southern regions, indicating regional diversity. The precipitation change also shows marked intraseasonal variations throughout the monsoon season. The temperature change shows a positive trend throughout 2021 2050 while the precipitation change is characterized by pronounced interdecadal variations. The PDF of the daily temperature is shifted towards higher values and is somewhat narrower in the scenario run than the reference one. The number of frost days decreases markedly and the number of hot days increases. The regional distribution of heavy precipitation (over 80 mm/day) changes considerably, indicating changes in flood vulnerable regions. The climate change signal shows pronounced fine scale signal over Korea, indicating the need of high-resolution climate simulations

  11. Mitral disc-valve variance

    PubMed Central

    Berroya, Renato B.; Escano, Fernando B.

    1972-01-01

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

  12. Echocardiographic features of aortic ball valve prosthesis malfunction.

    PubMed

    Weisburst, M R; Singh, A K; Riley, R S

    1982-11-01

    A case of aortic ball valve prosthesis malfunction is described in which the poppet became alternately stuck in the open and closed position. The patient experienced chest pain followed by pulmonary edema and cardiac arrest. Malfunction of prosthetic valve was diagnosed on echocardiogram and cardiopulmonary resuscitation was carried out until a Bjork-Shiley valve could be inserted in place of the faulty prosthesis. At the time of the operation, poppet migration had occurred and the poppet could not be found. Subsequent Bjork-Shiley aortic valve prosthesis dysfunction was suggested by variation in the intensity of the aortic opening sound and in the duration of the systolic ejection period. Fluoroscopy revealed the missing poppet in the left ventricle. Following surgical removal of the poppet, "normal" Bjork-Shiley valve function was restored.

  13. 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

  14. 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

  15. Implantation of the CoreValve percutaneous aortic valve.

    PubMed

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

    2007-01-01

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

  16. Computer aided detection of endobronchial valves

    NASA Astrophysics Data System (ADS)

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

    2008-03-01

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

  17. [Ileocecal valve reconstruction in dogs].

    PubMed

    Maegawa, Felipe Antonio Boff; de Souza, José Antônio; de Araújo, Edevard José; Koh, Ivan Hong Jun; d'Acampora, Armando José; de Farias, Débora Cadore; Mengarda, Jackson; Volpato, Daniel; da Silva, Luis Gustavo Ferreira; de Córdova, Cleta Selva

    2005-01-01

    The importance of keeping the ileocecal valve in the intestinal ressections has been reported by several authors. When preserved, the ileocecal valve was related to a longer survival and prevention of the short bowel syndrome, due to its ability to block the colonic content reflux into the ileum and to avoid the rapid empting of the ileal content into the cecum. It was assessed a tecnique of ileocecal valve reconstitution, based on vesicoureteral anti-reflux tecniques. Fourteen beagles were operated. Seven underwent ileocecal valve reconstitution following the tecnique proposed and in the other seven a simple end-to-end anastomosis was performed. To assess the new valve, it was done the clinical follow up, the microbiologic analysis and the manometric study. Clinically, during 45 days of follow up, there was no difference between the dogs with and without ileocecal reconstitution. In the aerobic bacteria analysis, the predominant bacterium was Escherichia coli. Quantitatively, the cultures grew in an irregular way, so that it was not able to compare the bacterial growth between the groups with or without ileocecal valve. The new valve had a colo-ileal reflux pressure similar to that of the physiological valve (P > 0.05). However, when compared to the non valve group, the reflux pressures of the physiological valve and new valve were significantly higher, with P < 0.05 and P < 0.001, respectively. In this study, the reconstituted ileocecal valve served as a barrier to the colo-ileal reflux just as the physiological valve does.

  18. 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.

  19. 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

  20. Fast closing valve

    SciTech Connect

    Hanson, C.L.

    1984-01-10

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

  1. Force generation of different human cardiac valve interstitial cells: relevance to individual valve function and tissue engineering.

    PubMed

    Smith, Sally; Taylor, Patricia M; Chester, Adrian H; Allen, Sean P; Dreger, Sally A; Eastwood, Mark; Yacoub, Magdi H

    2007-07-01

    Cardiac valves perform highly sophisticated functions that depend upon the specific characteristics of the component interstitial cells (ICs). The ability of valve ICs to contribute to these functions may be related to the generation of different types of tension within the valve structure. The study aim was to characterize cellular morphology and the forces generated by valve ICs and to compare this with morphology and forces generated by other cell types. Cultured human valve ICs, pericardial fibroblasts and vascular smooth muscle cells were seeded in 3-D collagen gels and placed in a device that accurately measures the forces generated. Cell morphology was determined in seeded gels fixed in glutaraldehyde, stained with toluidine blue and visualized using a high-definition stereo light microscope. Valve ICs generated an average peak force of 30.9 +/- 10.4 dynes over a 24-h period which, unlike other cell types tested, increased as cell density decreased (R = 0.67, p <0.0001). The temporal pattern of force generation in mitral valve cells was significantly faster than in aortic or tricuspid cells (p <0.05). Microscopic examination revealed the formation of cellular processes establishing a cell/cell and cell/matrix network. When externally induced changes in matrix tension occurred, the valve ICs unlike the other cell types - did not respond to restore the previous level of tension. Human cardiac valve ICs produce a specific pattern of force generation that may be related to the individual function of each heart valve. The specialized function of these cells may serve as a guide for the choice of candidate cells for tissue engineering heart valves.

  2. 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

  3. 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

  4. Aortic valve replacement with the De Bakey valve.

    PubMed

    Paton, B C; Pine, M B

    1976-10-01

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

  5. 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

  6. 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

  7. 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

  8. Aortic valve surgery - minimally invasive

    MedlinePlus

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

  9. Medications for Heart Valve Symptoms

    MedlinePlus

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

  10. 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.

  11. 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.

  12. What Is Mitral Valve Prolapse?

    MedlinePlus

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

  13. Diseases of the Tricuspid Valve

    MedlinePlus

    ... diseases of the tricuspid valve are regurgitation and stenosis. Tricuspid Regurgitation Tricuspid regurgitation is also called tricuspid ... the tricuspid valve may also be needed. Tricuspid Stenosis Tricuspid stenosis is a narrowing or blockage of ...

  14. What Causes Heart Valve Disease?

    MedlinePlus

    ... this page from the NHLBI on Twitter. What Causes Heart Valve Disease? Heart conditions and other disorders, age-related changes, rheumatic fever, or infections can cause acquired heart valve disease. These factors change the ...

  15. 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.

  16. 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.

  17. Sliding valve pump

    SciTech Connect

    Rupert, C.L.

    1980-09-09

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

  18. 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

  19. 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.

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

    PubMed

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

    2015-03-01

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

  1. Parachute mitral valve: morphologic descriptors, associated lesions, and outcomes after biventricular repair.

    PubMed

    Marino, Bradley S; Kruge, Lydia E; Cho, Catherine J; Tomlinson, Ryan S; Shera, David; Weinberg, Paul M; Gaynor, J William; Rychik, Jack

    2009-02-01

    In "true" parachute mitral valve, mitral valve chordae insert into one papillary muscle. In parachute-like asymmetric mitral valve, most or all chordal attachments are to one papillary muscle. This study compared morphologic features, associated lesions, and palliation strategies of the two parachute mitral valve and dominant papillary muscle types and examined interventions and midterm outcomes in patients with biventricular circulation. Echocardiography and autopsy databases were reviewed to identify patients with "true" parachute mitral valve or parachute-like asymmetric mitral valve from January 1987 to January 2006. Predictors of palliation strategy in the entire cohort, mitral stenosis on initial echocardiogram, and mortality in the biventricular cohort were determined with logistic regression. Eighty-six patients with "true" parachute mitral valve (n = 49) or parachute-like asymmetric mitral valve (n = 37) were identified. Chordal attachments to the posteromedial papillary muscle were more common (73%). The presence "true" parachute mitral valve (P = .008), hypoplastic left ventricle (P < .001), and two or more left-sided obstructive lesions (P = .002) predicted univentricular palliation. Among 49 patients maintaining biventricular circulation at follow-up, 8 died median follow-up 6.4 years (7 days-17.8 years). Multivariate analysis revealed that "true" parachute mitral valve was associated with mitral stenosis on initial echocardiogram (P = .03), and "true" parachute mitral valve (P = .04) and conotruncal anomalies (P = .0003) were associated with mortality. Progressive mitral stenosis was found in 11 patients; 2 underwent mitral valve interventions, and 1 died. Nearly two thirds of this parachute mitral valve cohort underwent biventricular palliation. Some progression of mitral stenosis occurred, although mitral valve intervention was rare. "True" parachute mitral valve was associated with mitral stenosis on initial echocardiogram. "True" parachute mitral

  2. 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.

  3. Pulsatile prosthetic valve flows.

    PubMed

    Phillips, W M; Snyder, A; Alchas, P; Rosenberg, G; Pierce, W S

    1980-01-01

    The laser Doppler system has been established as a useful tool for eliciting the properties of simulated cardiovascular flows, and thus for comparative studies of flow properties of prosthetic valves. Significant differences among valve types and between models of one type have been documented. The complex variations of velocity profiles with time show that comparisons must be made for unsteady pulsatile rather than steady flow, despite the volume and complexity of the data required. Future studies will include methods of compacting the data presentation and improving the details of the experimental stimulation.

  4. Ball valve safety screen

    SciTech Connect

    Bolding, B.H.

    1981-09-01

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

  5. Lipomatous hamartoma of mitral valve.

    PubMed

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

    2016-01-01

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

  6. 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.

  7. 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.

  8. Well safety and kill valve

    SciTech Connect

    Deaton, T.M.

    1986-12-30

    A valve device is described for use in tubing above a packer set in casing above a well formation comprising: (a) a housing connectable in well tubing and having a longitudinal flow passage therethrough and a flow passage through the housing wall intersecting the longitudinal flow passage; (b) lower ball valve means controlling flow through the longitudinal flow passage; (c) upper sleeve valve means controlling flow through the housing wall flow passages between the valve device exterior and the longitudinal flow passage. The valve means is cooperable such that when the upper valve means is in closed position, the lower valve means is in open position, and when the upper valve means is in open position, the lower valve means is in closed position; (d) locking means for holding the valve means at one position and releasing the valve means for movement to another position; (e) pressure responsive means for releasing the locking means; and (f) operator means for operating the valve means between positions including an operator tube having a shoulder thereon, mounted for longitudinal movement in the housing, an internal shoulder in the housing and a spring disposed around the operator tube between the housing and operator tube shoulders, biasing the operator tube upwardly.

  9. 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.

  10. 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.

  11. Prosthetic valve endocarditis: clinical findings and management.

    PubMed

    Horstkotte, D; Körfer, R; Loogen, F; Rosin, H; Bircks, W

    1984-10-01

    Prosthetic valve endocarditis (PVE) was shown in 46 patients out of a group of 2163 carrying prosthetic heart valves. The cumulative rate of early PVE was 1.4% and 1.5% for PVE occurring between the 60th day and 10 years after surgery. In 37% of all cases this was caused by staphylococci, 20% by streptococci, and 13% Gram negative species. Fungi were found in 9% and mixed infections in 21%. The incidence of staphylococci, Gram negative pathogens and fungi was significantly higher in early PVE. In 5 patients, valve involvement consisted in echocardiographically shown vegetations and/or obstructive thromboendocarditis. In 90% of 37 patients who developed paravalvular leakages, there was high intravascular haemolysis uncharacteristic of the type of prosthesis implanted. In 70% fluoroscopy revealed disproportionate tilting of the prosthetic annulus, and in 75% there was a distinct echocardiographic pattern in the closing movement of the valve poppet. The cumulative survival rate after six months was 31% for the conservatively treated, and 66% for the medically plus surgically treated patients. Survival rates at the end of a maximum follow-up of 20 years was 15% with conservative treatment and 51% after primary surgical therapy. The prognosis was worse (P less than 0.01) in patients who, during aortic PVE, developed heart failure refractant to therapy due to haemodynamically significant prosthetic valve dysfunction, to sepsis that persisted for more than 72 h despite antibiotic therapy, to major septic embolism or to acute renal failure. The retrospective prognosis was more favourable for patients with early aortic (P less than 0.02) or mitral (P less than 0.05) valve re-replacement than for patients who had been treated medically only.

  12. 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.

  13. Differential cell-matrix responses in hypoxia-stimulated aortic versus mitral valves.

    PubMed

    Sapp, Matthew C; Krishnamurthy, Varun K; Puperi, Daniel S; Bhatnagar, Saheba; Fatora, Gabrielle; Mutyala, Neelesh; Grande-Allen, K Jane

    2016-12-01

    Tissue oxygenation often plays a significant role in disease and is an essential design consideration for tissue engineering. Here, oxygen diffusion profiles of porcine aortic and mitral valve leaflets were determined using an oxygen diffusion chamber in conjunction with computational models. Results from these studies revealed the differences between aortic and mitral valve leaflet diffusion profiles and suggested that diffusion alone was insufficient for normal oxygen delivery in mitral valves. During fibrotic valve disease, leaflet thickening due to abnormal extracellular matrix is likely to reduce regional oxygen availability. To assess the impact of low oxygen levels on valve behaviour, whole leaflet organ cultures were created to induce leaflet hypoxia. These studies revealed a loss of layer stratification and elevated levels of hypoxia inducible factor 1-alpha in both aortic and mitral valve hypoxic groups. Mitral valves also exhibited altered expression of angiogenic factors in response to low oxygen environments when compared with normoxic groups. Hypoxia affected aortic and mitral valves differently, and mitral valves appeared to show a stenotic, rheumatic phenotype accompanied by significant cell death. These results indicate that hypoxia could be a factor in mid to late valve disease progression, especially with the reduction in chondromodulin-1 expression shown by hypoxic mitral valves. © 2016 The Author(s).

  14. Early-onset Streptomyces endocarditis in a prosthetic aortic valve.

    PubMed

    Shehatha, Jaffar S; Taha, Abdulsalam Y

    2017-02-01

    A 66-year-old Australian man underwent elective replacement of a severely stenotic aortic valve with a 22-mm Medtronic-Hall valve. Six weeks later, he was readmitted with worsening dyspnea, fever, and mild anemia. Investigations confirmed pulmonary edema and moderate periprosthetic aortic regurgitation. The pulmonary edema was managed conservatively, and a second 22-mm Medtronic-Hall valve was implanted. Infective endocarditis was suspected in the aortic annulus below the orifice of the right coronary artery. A bacteriological study revealed a rare bacteria of Streptomyces species. The patient received intensive antibiotic therapy over a 6-week period of hospitalization, and the aortic regurgitation disappeared one week postoperatively.

  15. Evaluation of a high response electrohydraulic digital control valve

    NASA Technical Reports Server (NTRS)

    Anderson, R. L.

    1973-01-01

    The application is described of a digital control valve on an electrohydraulic servo actuator. The digital control problem is discussed in general as well as the design and evaluation of a breadboard actuator. The evaluation revealed a number of problems associated with matching the valve to a hydraulic load. The problems were related to lost motion resulting from bulk modulus and leakage. These problems were effectively minimized in the breadboard actuator by maintaining a 1000 psi back pressure on the valve circuit and thereby improving the effective bulk modulus.

  16. 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.

  17. Transcatheter aortic valve replacement

    MedlinePlus

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

  18. 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.

  19. Mitral Valve Prolapse

    MedlinePlus

    ... Search By Zipcode Search by State SELECT YOUR LANGUAGE Español (Spanish) 简体中文 (Traditional Chinese) 繁体中文 (Simplified Chinese) ... Walk through a step-by-step interactive guide explaining your valve issue and treatment options with helpful ...

  20. Stennis tests shuttle valves

    NASA Image and Video Library

    2009-02-12

    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.

  1. 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.

  2. Poppet valve tester

    NASA Technical Reports Server (NTRS)

    Tellier, G. F.

    1973-01-01

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

  3. Valved molecular beam skimmer

    NASA Astrophysics Data System (ADS)

    Marceca, Ernesto; Becker, Jörg A.; Hensel, Friedrich

    1997-08-01

    Under routine source conditions, the optimum nozzle-skimmer distance to achieve maximum molecular beam intensities is within the range of a few millimeters. In cases where double skimming is additionally required, the distance between the skimmers should be kept small in order to sample a sufficiently large solid angle of the beam and hence maintain a good enough intensity. These two facts make it normally difficult to isolate the first from the second expansion chamber using a commercial vacuum gate valve due to the lack of remaining space. This note presents the design of a vacuum-tight valve which allows the aperture of a skimmer to be closed by plugging a needle directly against its internal conical wall. The valve can be driven manually or pneumatically from outside the vacuum chamber. The helium conductance of the valve was measured to be better than 1×10-8 mbar×l×s-1 for a helium partial pressure difference of 1 bar.

  4. 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.

  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. 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.

  7. 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.

  8. Posttraumatic tricuspid valve injury and severe tricuspid valve regurgitation.

    PubMed

    Gucuk Ipek, Esra

    2013-09-01

    A 66-year-old male was brought to our hospital following a car accident. He had subarachnoid hemorrhage, multiple rib fractures, and left hemopneumothorax. He was referred to the Cardiology Department for elevated troponin levels (42 ng/ml, reference 0-1 ng/ml). The electrocardiogram was free of ischemia, whereas the transthoracic echocardiography revealed dilated right heart chambers, enlarged tricuspid annulus and coaptation failure of the tricuspid valvular leaflets. There was rupture on the subvalvular apparatus of the anterior leaflet of the tricuspid valve with accompanying prolapse, causing severe tricuspid valvular regurgitation. The patient did not present right ventricular failure signs and symptoms; he was referred to surgery after the resolution of associated thoracic and cranial injuries.

  9. Valve assembly for internal combustion engine

    SciTech Connect

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

    1989-09-05

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

  10. 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.

  11. 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.

  12. Cusp tear in bicuspid aortic valve possibly caused by phentermine.

    PubMed

    Yosefy, Chaim; Berman, Michael; Beeri, Ronen

    2006-01-13

    A 28 year old woman underwent echocardiography following an incidental finding of a diastolic murmur. She has been taking phentermine for weight reduction for 8 months. Trans-esophageal echocardiography revealed a tear of the posterior cusp of the aortic valve causing severe regurgitation. Phentermine is known to cause valvular disease with prolonged use, but aortic valve rupture was not previously reported as a complication of phentermine valvulopathy.

  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. © The Author(s) 2014.

  14. Anterior Urethral Valve: Uncommon Association with Renal Duplicity

    PubMed Central

    Salem, Amina Ben; Mazhoud, Ines; Laamiri, Rachida; Salem, Randa; Laajili, Hayet; Sahnoun, Lassaad; Hafsa, Chiraz

    2017-01-01

    Anterior urethral valves (AUVs) is an unusual cause of congenital obstruction of the male urethra, being 15–30 times less common than posterior urethral valves. We present a case of AUV diagnosed at 24th gestational week. Ultrasonography and fetal MRI revealed hydronephrotic kidneys with ureteral duplicity, a distended bladder and perineal cystic mass which confirmed dilated anterior urethra in a male fetus. Diagnosis was confirmed postnatally by voiding cystourethrogram and surgery. PMID:28770138

  15. Conventional versus rapid-deployment aortic valve replacement: a single-centre comparison between the Edwards Magna valve and its rapid-deployment successor†

    PubMed Central

    Andreas, Martin; Wallner, Stephanie; Habertheuer, Andreas; Rath, Claus; Schauperl, Martin; Binder, Thomas; Beitzke, Dietrich; Rosenhek, Raphael; Loewe, Christian; Wiedemann, Dominik; Kocher, Alfred; Laufer, Guenther

    2016-01-01

    OBJECTIVES Sutureless and rapid-deployment valves were recently introduced into clinical practice. The Edwards INTUITY valve system is a combination of the Edwards Magna pericardial valve and a subvalvular stent-frame to enable rapid deployment. We performed a parallel cohort study for comparison of the two valve types. METHODS All patients receiving either an Edwards Magna Ease valve or an Edwards INTUITY valve system due to aortic stenosis from May 2010 until July 2014 were included. Patients undergoing bypass surgery, an additional valve procedure, atrial ablation surgery or replacement of the ascending aorta were excluded. Preoperative characteristics, operative specifications, survival, valve-related adverse events and transvalvulvar gradients were compared. RESULTS One hundred sixteen patients underwent rapid-deployment aortic valve replacement [mean age 75 years (SD: 8); 62% female] and 132 patients underwent conventional aortic valve replacement [70 years (SD: 9); 31% female; P < 0.001]. Conventional valve patients were taller and heavier. The mean EuroSCORE II was 3.1% (SD: 2.7) and 4.4% (SD: 6.0) for rapid-deployment and conventional valve patients, respectively (P = 0.085). The mean implanted valve size was higher in the conventional group [23.2 mm (SD: 2.0) vs 22.5 mm (SD: 2.2); P = 0.007], but postoperative transvalvular mean gradients were comparable [15 mmHg (SD: 6) vs 14 mmHg (SD: 5); P = 0.457]. A subgroup analysis of the most common valve sizes (21 and 23 mm; implanted in 63% of patients) revealed significantly reduced mean postoperative transvalvular gradients in the rapid-deployment group [14 mmHg (SD: 4) vs 16 mmHg (SD: 5); P = 0.025]. A significantly higher percentage received minimally invasive procedures in the rapid-deployment group (59 vs 39%; P < 0.001). The 1- and 3-year survival rate was 96 and 90% in the rapid-deployment group and 95 and 89% in the conventional group (P = 0.521), respectively. Valve-related pacemaker implantations were

  16. Effect of nasal speaking valve on speech intelligibility under velopharyngeal incompetence: a questionnaire survey.

    PubMed

    Mikamo, S; Kodama, N; Pan, Q; Maeda, N; Minagi, S

    2015-02-01

    Velopharyngeal incompetence is known as a contributing factor to speech disorders. Suwaki et al. reported that nasal speaking valve (NSV) could improve dysarthria by regulating nasal emission utilising one-way valve. However, disease or condition which would be susceptible to treatment by NSV has not been clarified yet. This study aimed to evaluate the effect of NSV by questionnaire survey using ready-made NSV. Subjects were recruited through the internet bulletin, and NSV survey set was sent to the applicant. Sixty-six participants, who agreed to participate in this study, used NSV and mailed back the questionnaire which included self-evaluation and third-party evaluation of speech intelligibility. Statistical analysis revealed that the use of NSV resulted in significant speech intelligibility improvement in both self-evaluation and third-party evaluation (P < 0·01). Regarding the type of underlying disease of dysarthria, significant effect of NSV on self-evaluation of speech intelligibility could be observed in cerebrovascular disease and neurodegenerative disease (P < 0·01) and that on third-party evaluation in neurodegenerative disease (P < 0·01). Eighty-six percent of subjects showed improvement of speech intelligibility by shutting up nostrils by fingers, and the significant effect of NSV on both self-evaluation and third-party evaluation of speech intelligibility was observed (P < 0·001). From the results of this study, it was suggested that NSV would be effective in cerebrovascular disease and neurodegenerative disease, as well as in subjects whose speech intelligibility was improved by closing nostrils.

  17. 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.

  18. 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.

  19. Surgical management of carcinoid heart valve disease.

    PubMed

    Castillo, Javier G; Milla, Federico; Adams, David H

    2012-01-01

    Carcinoid tumors are neuroendocrine tumors with an unpredictable clinical behavior. In the setting of hepatic metastases, the release of bioactive amines from the tumor into the systemic circulation results in carcinoid syndrome: a constellation of clinical symptoms, among which cutaneous flushing, gastrointestinal hypermotility, and cardiac involvement are the most frequent. Cardiac manifestations, also known as carcinoid heart disease, are secondary to a severe endocardial fibrotic reaction that leads to progressive valve thickening and retraction. Imaging studies commonly reveal severe right-sided valve disease, with fixed leaflets or cusps in a semiopen position. The replacement of the right-sided valves, including the patch enlargement of the right ventricular outflow tract, is currently the only definitive treatment to potentially improve quality of life and provide survival benefit. Although cardiac surgery has been traditionally reserved for those patients with symptomatic right ventricular failure, a significant trend toward improved surgical outcomes has triggered a more liberal referral for valve replacement during the past decade. Copyright © 2012 Elsevier Inc. All rights reserved.

  20. Interlayer quality dependent graphene spin valve

    NASA Astrophysics Data System (ADS)

    Iqbal, Muhammad Zahir; Hussain, Ghulam; Siddique, Salma; Iqbal, Muhammad Waqas; Murtaza, Ghulam; Ramay, Shahid Mahmood

    2017-01-01

    It is possible to utilize the new class of materials for emerging two-dimensional (2D) spintronic applications. Here, the role of defects in the graphene interlayer and its influence on the spin valve signal is reported. The emergence of D peak in Raman spectrum reveals defects in the graphene layer. The linear I-V curve for defective and non-defective graphene samples indicate the ohmic nature of NiFe and graphene contact. A non-uniform magnetoresistive effect with a bump is persistently observed for defective graphene device at various temperatures, while a smooth and symmetric signal is detected for non-defective graphene spin valve. Parallel and antiparallel alignments of magnetization of magnetic materials shows low and high resistance states, respectively. The magnetoresistance (MR) ratio for defective graphene NiFe/graphene/NiFe spin valve is measured to be 0.16% at 300 K which progresses to 0.39% for non-defective graphene device at the same temperature. Similarly at 4.2 K the MR ratios are reported to be 0.41% and 0.78% for defective and non-defective graphene devices, respectively. Our investigation provides an evidence for relatively better response of the spin valve signal with high quality graphene interlayer.

  1. Aspiration of a speaking valve

    PubMed Central

    Schembri, John; Cortis, Kelvin; Mallia Azzopardi, Charles; Montefort, Stephen

    2013-01-01

    Foreign body aspiration (FBA) is a relatively common and serious condition that can result in a spectrum of presentations ranging from incidental to acutely life-threatening. Described here is a case of aspiration of a tracheo-oesophageal speaking valve through a permanent tracheostomy that went unnoticed for a number of years, and an overview of the technique used for its removal. A 70-year-old ex-heavy smoker with a permanent tracheo-oesophageal fistula presented with a relatively recent history of increasing shortness of breath, sputum purulence and haemoptysis. Further investigation with a CT scan and bronchoscopy revealed the presence of a foreign body within his right lower lobe bronchus which was later removed by advancing a flexible bronchoscope over a rigid one. PMID:23861275

  2. [Status of aortic valve reconstruction and Ross operation in aortic valve diseases].

    PubMed

    Sievers, Hans H

    2002-08-01

    At first glance the aortic valve is a relative simple valve mechanism connecting the left ventricle and the ascending aorta. Detailed analysis of the different components of the aortic valve including the leaflets and sinuses revealed a complex motion of each part leading to a perfect durable valve mechanism at rest and during exercise. Theoretically, the reconstruction or imitation of these structures in patients with aortic valve disease should lead to optimal results. Prerequisite is the exact knowledge of the important functional characteristics of the aortic valve. The dynamic behavior of the aortic root closely harmonizing with the leaflets not only warrants stress minimizing and valve durability, but also optimizes coronary flow, left ventricular function and aortic impedance. The newly discovered contractile capacity of the leaflets and the root components are important for tuning the dynamics. Isolated reconstruction of the aortic valve such as decalcification, commissurotomy, plication of ring or leaflets of a tricuspid aortic valve and cusp extension are seldom indicated in contrast to the reconstruction of the bicuspid insufficient valve. Proper indication and skilled techniques lead to excellent hemodynamic and clinical intermediate-term result up to 7 years after reconstruction. Latest follow-up revealed a mean aortic insufficiency of 0.7, maximal pressure gradient of 11.4 +/- 8.5 mm Hg with zero hospital or late mortality, reoperation or thromboembolic events in 22 patients. The reconstructive techniques for aortic root aneurysm and/or type A dissection according to David or Yacoub have become routine procedures in the last 10 years. The hemodynamic and clinical results are excellent with low reoperation rate and very low risk of thromboembolism. Generally, a maximal diameter of the root of 5 cm is indicative for performing the operation. In patients with Marfan's syndrome the reconstruction should be advanced even with smaller diameters especially

  3. Heart failure due to "disappearing" aortic valve in hypoplastic left heart syndrome.

    PubMed

    Loftus, Patrick D; Erickson, Lance K; Everitt, Melanie D; Kaza, Aditya K

    2014-04-01

    We present the unusual case of a "disappearing" aortic valve in an infant with hypoplastic left heart syndrome (mitral and aortic stenosis) that underwent Norwood palliation at birth and subsequently a Glenn operation. Angiographic images at the time of operation showed no apparent insufficiency of the native aortic valve. Over the course of 14 months following operation, the patient developed significant cardiomegaly with a workup revealing severe native aortic valve insufficiency. Following orthotopic heart transplantation, examination of the explanted heart revealed a complete absence of native aortic valve leaflets.

  4. Paravalvular leakage causing hemolytic anemia at 8-9 years after mitral valve replacement.

    PubMed

    Misawa, Yoshio; Konishi, Hiroaki; Saito, Tsutomu; Fuse, Katsuo

    2002-12-01

    We report two similar cases of women, aged 52 and 71 years, who developed shortness of breath or easy fatigability at 8-9 years after mitral valve replacement of the mitral valve in each patient, the echocardiographic study revealed paravalvular leakage. Previous examination before the appearance of symptoms had revealed a well-functioned prosthetic valve, and no hematological abnormality had been detected. The hemoglobin levels at admission were 6.4 and 6.6 g/dl, and their serum lactate dehydrogenase levels were 5218 and 4608 mU/ml. Each successfully underwent another valve replacement, and after surgery, the hemolytic anemia and the symptoms disappeared.

  5. [Totally robotic mitral valve surgery in 60 cases].

    PubMed

    Yang, Ming; Gao, Chang-qing; Wang, Gang; Wang, Jia-li; Xiao, Cang-song; Wu, Yang

    2011-10-01

    To evaluate the safety and efficacy of robotic mitral valve surgery using da Vinci S system. We conducted a retrospective review of 60 robotic mitral surgeries from March 2007 to December 2010. Of the 60 patients, 44 underwent mitral valve repair and 16 received mitral valve replacement. The surgical approach was through 4 right chest ports with femoral and internal jugular vein cannulations. Transesophageal echocardiography was used intraoperatively to estimate the surgical results. None of the cases required a conversion to a median sternotomy. The mean cardiopulmonary bypass and cardiac arrest time was 132.2∓29.6 min and 88.1∓22.3 min for robotic mitral valve repair, and was 137.1∓21.9 min and 99.3∓17.4 min for robotic mitral valve replacement. Echocardiographic follow-up of all the patients revealed 3 cases of slight regurgitation in mitral valve repair group. In selected patients with mitral valve disease, robotic mitral surgery can be performed safely.

  6. 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.

  7. 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.

  8. 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.

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

    PubMed

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

    2016-03-01

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

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Proof-of-Concept Evaluation of the SailValve Self-Expanding Deep Venous Valve System in a Porcine Model.

    PubMed

    Boersma, Doeke; Vink, Aryan; Moll, Frans L; de Borst, Gert J

    2017-06-01

    To evaluate the SailValve, a new self-expanding deep venous valve concept based on a single polytetrafluoroethylene cusp floating up and down in the bloodstream like a sail, acting as a flow regulator and allowing minimal reflux to reduce thrombogenicity. Both iliac veins of 5 pigs were implanted with SailValve devices; the first animal was an acute pilot experiment to show the feasibility of accurately positioning the SailValve via a femoral access. The other 4 animals were followed for 2 weeks (n=2) or 4 weeks (n=2) under a chronic implantation protocol. Patency and valve function were evaluated directly in all animals using ascending and descending phlebography after device placement and at termination in the chronic implant animals. For reasons of clinical relevance, a regimen of clopidogrel and calcium carbasalate was administered. Histological analysis was performed according to a predefined protocol by an independent pathologist. Deployment was technically feasible in all 10 iliac veins, and all were patent directly after placement. No perioperative or postoperative complications occurred. Ascending phlebograms in the follow-up animals confirmed the patency of all valves after 2 or 4 weeks. Descending phlebograms showed full function in 5 of 8 valves. Limited reflux was seen in 1 valve (4-week group), and the function in the remaining 2 valves (2-week group) was insufficient because of malpositioning. No macroscopic thrombosis was noted on histology. Histology in the follow-up groups revealed a progressive inflammatory reaction to the valves. This animal study shows the potential of the SailValve concept with sufficient valve function after adequate positioning and no (thrombogenic) occlusions after short-term follow-up. Future research is essential to optimize valve material and long-term patency.

  15. 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.

  16. 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

  17. 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.

  18. Passive bypass valve assembly

    SciTech Connect

    Siedlecki, W.F. Jr.

    1992-05-19

    This patent describes a bypass valve assembly for controlling fluid flow in a gas turbine engine. It comprises an annular frame including an outer casing, an inner casing spaced from the outer casing to define a channel for channeling fluid flow and the outer casing including an annular opening therein; a plurality of circumferentially juxtaposed bypass valve doors disposed in the annular opening, each of the valve doors having an inner surface for facing the fluid flowable in the channel, an outer surface, a first end pivotally connected to the frame, and a second end, the doors being positionable in a first position generally parallel to the outer casing, and in a second position inclined relative to the outer casing, the fluid flow flowable against the door inner surface being effective for generating a fluid force on the door; and means for automatically positioning the doors in first and second positions in response to differential pressure across the door, the positioning means providing a torque on the doors for moving the door from the first to the second positions and including torque adjustment means for reducing the torque for at least a portion of travel of the doors from the second to the first positions.

  19. Modeling the Myxomatous Mitral Valve With Three-Dimensional Echocardiography.

    PubMed

    Pouch, Alison M; Jackson, Benjamin M; Lai, Eric; Takebe, Manabu; Tian, Sijie; Cheung, Albert T; Woo, Y Joseph; Patel, Prakash A; Wang, Hongzhi; Yushkevich, Paul A; Gorman, Robert C; Gorman, Joseph H

    2016-09-01

    Degenerative mitral valve disease is associated with variable and complex defects in valve morphology. Three-dimensional echocardiography (3DE) has shown promise in aiding preoperative planning for patients with this disease but to date has not been as transformative as initially predicted. The clinical usefulness of 3DE has been limited by the laborious methods currently required to extract quantitative data from the images. To maximize the utility of 3DE for preoperative valve evaluation, this work describes an automated 3DE image analysis method for generating models of the mitral valve that are well suited for both qualitative and quantitative assessment. The method is unique in that it captures detailed alterations in mitral leaflet and annular morphology and produces image-derived models with locally varying leaflet thickness. The method is evaluated on midsystolic transesophageal 3DE images acquired from 22 subjects with myxomatous degeneration and from 22 subjects with normal mitral valve morphology. Relative to manual image analysis, the automated method accurately represents both normal and complex leaflet geometries with a mean boundary displacement error on the order of one image voxel. A detailed quantitative analysis of the valves is presented and reveals statistically significant differences between normal and myxomatous valves with respect to numerous aspects of annular and leaflet geometry. This work demonstrates a successful methodology for the relatively rapid quantitative description of the complex mitral valve distortions associated with myxomatous degeneration. The methodology has the potential to significantly improve surgical planning for patients with complex mitral valve disease. Copyright © 2016 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  20. Modeling the Myxomatous Mitral Valve With Three-Dimensional Echocardiography

    PubMed Central

    Pouch, Alison M.; Jackson, Benjamin M.; Lai, Eric; Takebe, Manabu; Tian, Sijie; Cheung, Albert T.; Woo, Y. Joseph; Patel, Prakash A.; Wang, Hongzhi; Yushkevich, Paul A.; Gorman, Robert C.; Gorman, Joseph H.

    2017-01-01

    Background Degenerative mitral valve disease is associated with variable and complex defects in valve morphology. Three-dimensional echocardiography (3DE) has shown promise in aiding preoperative planning for patients with this disease but to date has not been as transformative as initially predicted. The clinical usefulness of 3DE has been limited by the laborious methods currently required to extract quantitative data from the images. Methods To maximize the utility of 3DE for preoperative valve evaluation, this work describes an automated 3DE image analysis method for generating models of the mitral valve that are well suited for both qualitative and quantitative assessment. The method is unique in that it captures detailed alterations in mitral leaflet and annular morphology and produces image-derived models with locally varying leaflet thickness. The method is evaluated on midsystolic transesophageal 3DE images acquired from 22 subjects with myxomatous degeneration and from 22 subjects with normal mitral valve morphology. Results Relative to manual image analysis, the automated method accurately represents both normal and complex leaflet geometries with a mean boundary displacement error on the order of one image voxel. A detailed quantitative analysis of the valves is presented and reveals statistically significant differences between normal and myxomatous valves with respect to numerous aspects of annular and leaflet geometry. Conclusions This work demonstrates a successful methodology for the relatively rapid quantitative description of the complex mitral valve distortions associated with myxomatous degeneration. The methodology has the potential to significantly improve surgical planning for patients with complex mitral valve disease. PMID:27492671

  1. Analysis of IR spectra of mineralized deposits on human cardiac valves

    NASA Astrophysics Data System (ADS)

    Ivanov-Omskii, V. I.; Yastrebov, S. G.; Gulyaev, N. I.

    2017-05-01

    IR spectroscopy in the range of vibration of hydroxy groups has been used to analyze the binding energy of mineralized deposits to cardiac valves of patients of varied gender and age. A tendency was revealed toward a gender-independent rise in the binding energy of mineralized deposits to valve tissues with increasing age of patients. The analysis enables making recommendations concerning the early diagnostics of valve calcination, monitoring of its development, and therapy of calcinoses.

  2. Primitive Tumour of the Pulmonary Valve: Discussion of the Differential Diagnosis

    PubMed Central

    Ndjekembo-Shango, D.; Vallot, F.; Simonet, O.; De Kock, M.

    2017-01-01

    There is a paucity of information concerning cardiac tumours of the pulmonary valve due to their rarity at this location. We report a case of a 47-year-old patient suffering from haemoptysis, asthenia, and acute kidney injury (AKI). A transthoracic echocardiography (TTE) revealed a mass on the pulmonary valve. Further diagnostic investigation was completed until he exhibited worsening hemodynamic instability. This case emphasizes the lack of information regarding the management of a pulmonary valve tumour. PMID:28299209

  3. 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.

  4. Optothermally actuated capillary burst valve

    NASA Astrophysics Data System (ADS)

    Eriksen, Johan; Bilenberg, Brian; Kristensen, Anders; Marie, Rodolphe

    2017-04-01

    We demonstrate the optothermal actuation of individual capillary burst valves in an all-polymer microfluidic device. The capillary burst valves are realised in a planar design by introducing a fluidic constriction in a microfluidic channel of constant depth. We show that a capillary burst valve can be burst by raising the temperature due to the temperature dependence of the fluid surface tension. We address individual valves by using a local heating platform based on a thin film of near infrared absorber dye embedded in the lid used to seal the microfluidic device [L. H. Thamdrup et al., Nano Lett. 10, 826-832 (2010)]. An individual valve is burst by focusing the laser in its vicinity. We demonstrate the capture of single polystyrene 7 μm beads in the constriction triggered by the bursting of the valve.

  5. 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. Copyright © 2016 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  6. Treatment of mechanical aortic valve thrombosis with heparin and eptifibatide.

    PubMed

    Vora, Amit N; Gehrig, Thomas; Bashore, Thomas M; Kiefer, Todd L

    2014-07-01

    A 75-year old woman with a history of coronary disease status post 3-vessel coronary artery bypass grafting (CABG) 8 years ago and a repeat one-vessel CABG 2 years ago in the setting of aortic valve replacement with a #19 mm St. Jude bileaflet mechanical valve for severe aortic stenosis presented with two to three weeks of progressive dyspnea and increasing substernal chest discomfort. Echocardiography revealed a gradient to 31 mmHg across her aortic valve, increased from a baseline of 13 mmHg five months previously. Fluoroscopy revealed thrombosis of her mechanical aortic valve. She was not a candidate for surgery given her multiple comorbidities, and fibrinolysis was contraindicated given a recent subdural hematoma 1 year prior to presentation. She was treated with heparin and eptifibatide and subsequently demonstrated resolution of her aortic valve thrombosis. We report the first described successful use of eptifibatide in addition to unfractionated heparin for the management of subacute valve thrombosis in a patient at high risk for repeat surgery or fibrinolysis.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Determinants of valve gating in collecting lymphatic vessels from rat mesentery.

    PubMed

    Davis, Michael J; Rahbar, Elaheh; Gashev, Anatoliy A; Zawieja, David C; Moore, James E

    2011-07-01

    Secondary lymphatic valves are essential for minimizing backflow of lymph and are presumed to gate passively according to the instantaneous trans-valve pressure gradient. We hypothesized that valve gating is also modulated by vessel distention, which could alter leaflet stiffness and coaptation. To test this hypothesis, we devised protocols to measure the small pressure gradients required to open or close lymphatic valves and determine if the gradients varied as a function of vessel diameter. Lymphatic vessels were isolated from rat mesentery, cannulated, and pressurized using a servo-control system. Detection of valve leaflet position simultaneously with diameter and intraluminal pressure changes in two-valve segments revealed the detailed temporal relationships between these parameters during the lymphatic contraction cycle. The timing of valve movements was similar to that of cardiac valves, but only when lymphatic vessel afterload was elevated. The pressure gradients required to open or close a valve were determined in one-valve segments during slow, ramp-wise pressure elevation, either from the input or output side of the valve. Tests were conducted over a wide range of baseline pressures (and thus diameters) in passive vessels as well as in vessels with two levels of imposed tone. Surprisingly, the pressure gradient required for valve closure varied >20-fold (0.1-2.2 cmH(2)O) as a passive vessel progressively distended. Similarly, the pressure gradient required for valve opening varied sixfold with vessel distention. Finally, our functional evidence supports the concept that lymphatic muscle tone exerts an indirect effect on valve gating.

  12. Determinants of valve gating in collecting lymphatic vessels from rat mesentery

    PubMed Central

    Rahbar, Elaheh; Gashev, Anatoliy A.; Zawieja, David C.; Moore, James E.

    2011-01-01

    Secondary lymphatic valves are essential for minimizing backflow of lymph and are presumed to gate passively according to the instantaneous trans-valve pressure gradient. We hypothesized that valve gating is also modulated by vessel distention, which could alter leaflet stiffness and coaptation. To test this hypothesis, we devised protocols to measure the small pressure gradients required to open or close lymphatic valves and determine if the gradients varied as a function of vessel diameter. Lymphatic vessels were isolated from rat mesentery, cannulated, and pressurized using a servo-control system. Detection of valve leaflet position simultaneously with diameter and intraluminal pressure changes in two-valve segments revealed the detailed temporal relationships between these parameters during the lymphatic contraction cycle. The timing of valve movements was similar to that of cardiac valves, but only when lymphatic vessel afterload was elevated. The pressure gradients required to open or close a valve were determined in one-valve segments during slow, ramp-wise pressure elevation, either from the input or output side of the valve. Tests were conducted over a wide range of baseline pressures (and thus diameters) in passive vessels as well as in vessels with two levels of imposed tone. Surprisingly, the pressure gradient required for valve closure varied >20-fold (0.1–2.2 cmH2O) as a passive vessel progressively distended. Similarly, the pressure gradient required for valve opening varied sixfold with vessel distention. Finally, our functional evidence supports the concept that lymphatic muscle tone exerts an indirect effect on valve gating. PMID:21460194

  13. 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.

  14. 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

  15. 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.

  16. Fluid mechanics of heart valves.

    PubMed

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

    2004-01-01

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

  17. 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.

  18. Incorporating measured valve properties into a numerical model of a lymphatic vessel

    PubMed Central

    Macaskill, C.; Moore, J.E.

    2015-01-01

    An existing lumped-parameter model of multiple lymphangions (lymphatic vascular segments) in series is adapted for the incorporation of recent physiological measurements of lymphatic vascular properties. The new data show very marked nonlinearity of the passive pressure-diameter relation during distension, relative to comparable blood vessels, and complex valve behaviour. Since lymph is transported as a result of either the active contraction or the passive squeezing of vascular segments situated between two one-way valves, the performance of these valves is of primary importance. The valves display hysteresis (the opening and closing pressure-drop thresholds differ), a bias to staying open (both state changes occur when the trans-valve pressure drop is adverse), and pressure-drop threshold dependence on transmural pressure. These properties, in combination with the strong nonlinearity that valve operation represents, have in turn caused intriguing numerical problems in the model, and we describe numerical stratagems by which we have overcome the problems. The principal problem is also generalised into a relatively simple mathematical example, for which solution detail is provided using two different solvers. PMID:23387996

  19. 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.

  20. 49 CFR 195.116 - Valves.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

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