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Sample records for internal seal ring

  1. Vacuum Packaging of MEMS With Multiple Internal Seal Rings

    NASA Technical Reports Server (NTRS)

    Hayworth, Ken; Yee, Karl; Shcheglov, Kirill; Bae, Youngsam; Wiberg, Dean; Peay, Chris; Challoner, Anthony

    2008-01-01

    A proposed method of design and fabrication of vacuum-packaged microelectromechanical systems (MEMS) and of individual microelectromechanical devices involves the use of multiple internal seal rings (MISRs) in conjunction with vias (through holes plated with metal for electrical contacts). The proposed method is compatible with mass production in a wafer-level fabrication process, in which the dozens of MEMS or individual microelectromechanical devices on a typical wafer are simultaneously vacuum packaged by bonding a capping wafer before the devices are singulated (cut apart by use of a dicing saw). In addition to being compatible with mass production, the proposed method would eliminate the need for some complex and expensive production steps and would yield more reliable vacuum seals. Conventionally, each MEMS or individual microelectromechanical device is fabricated as one of many identical units on a device wafer. Vacuum packaging is accomplished by bonding the device wafer to a capping wafer with metal seal rings (one ring surrounding each unit) that have been formed on the capping wafer. The electrical leads of each unit are laid out on what would otherwise be a flat surface of the device wafer, against which the seal ring is to be pressed for sealing. The resulting pattern of metal lines and their insulating oxide coverings presents a very rough and uneven surface, upon which it is difficult to pattern the sealing metal. Consequently, the seal is prone to leakage unless additional costly and complex planarization steps are performed before patterning the seal ring and bonding the wafers.

  2. Multiple internal seal ring micro-electro-mechanical system vacuum packaging method

    NASA Technical Reports Server (NTRS)

    Hayworth, Ken J. (Inventor); Yee, Karl Y. (Inventor); Shcheglov, Kirill V. (Inventor); Bae, Youngsam (Inventor); Wiberg, Dean V. (Inventor); Challoner, A. Dorian (Inventor); Peay, Chris S. (Inventor)

    2008-01-01

    A Multiple Internal Seal Ring (MISR) Micro-Electro-Mechanical System (MEMS) vacuum packaging method that hermetically seals MEMS devices using MISR. The method bonds a capping plate having metal seal rings to a base plate having metal seal rings by wafer bonding the capping plate wafer to the base plate wafer. Bulk electrodes may be used to provide conductive paths between the seal rings on the base plate and the capping plate. All seals are made using only metal-to-metal seal rings deposited on the polished surfaces of the base plate and capping plate wafers. However, multiple electrical feed-through metal traces are provided by fabricating via holes through the capping plate for electrical connection from the outside of the package through the via-holes to the inside of the package. Each metal seal ring serves the dual purposes of hermetic sealing and providing the electrical feed-through metal trace.

  3. Seal ring installation tool

    NASA Technical Reports Server (NTRS)

    Haselmaier, L. Haynes (Inventor)

    2004-01-01

    A seal ring tool that allows an installer to position a primary seal ring between hub ends of pipe flanges that are being assembled together. The tool includes a pivoting handle member and extension arms attached to the pivoting handle member. The ends of the arms have side indentation type longitudinal grooves angled toward one another for holding the primary seal ring in place between the hubs of respective pipes that are to be attached together. The arms of the tool can also have flat sides that can be used to abut against an optional second larger seal that is supported within a groove in one of the hub ends so that the second hub end can then be moved against the other side of the primary seal ring. Once the seal ring is positioned between the pipe hubs, the pipe hubs can be moved about the seal ring due to the flat sides of the arms of the tool. The tool eliminates the chances of damaging and contaminating seal rings being installed within pipe hubs that are being attached to one another.

  4. Conical O-ring seal

    DOEpatents

    Chalfant, Jr., Gordon G.

    1984-01-01

    A shipping container for radioactive or other hazardous materials which has a conical-shaped closure containing grooves in the conical surface thereof and an O-ring seal incorporated in each of such grooves. The closure and seal provide a much stronger, tighter and compact containment than with a conventional flanged joint.

  5. Conical O-ring seal

    DOEpatents

    Chalfant, G.G. Jr.

    A shipping container for radioactive or other hazardous materials has a conical-shaped closure containing grooves in the conical surface thereof and an O-ring seal incorporated in each of such grooves. The closure and seal provide a much stronger, tighter and compact containment than with a conventional flanged joint.

  6. Reactor cavity seal ring

    SciTech Connect

    Hankinson, M.F.

    1986-04-22

    A hydrostatic seal is described for sealing an annular gap between two flat substantially horizontal coplanar surfaces comprising, in combination: a generally flat annular plate of a width sufficient to span a gap between two surfaces: compressible annular sealing means disposed on the bottom surface of the flat annular plate for sealingly engaging the two flat surfaces in response to a downward force exerted on the plate; and fastening means, distributed along the center line of the plate, for releasably fastening the plate in a position to span the gap to be sealed and exert a downward force on the plate, each fastening means including a pair of elongated members of a size to fit into the gap to be sealed, means for mounting the members on the bottom surface of the plate so that at least a portion of each member is radially moveable in a direction toward a respective one of the vertical side surfaces defining the gap to be sealed to engage same and so that the plate is moveable relative to the members in a downward direction in response to hydrostatic pressure applied to the upper surface of the plate when the members are engaging the vertical side surfaces of an annular gap, and an actuating means, mounted on the plate for movement therewith in response to hydrostatic pressure, for radially moving the members, the actuating means extending through a bore in the plate to the upper surface of the plate.

  7. Split-ring seal

    NASA Technical Reports Server (NTRS)

    Gallo, E. A.

    1976-01-01

    Gland-type seal may be used with hydraulic and pneumatic actuators and similar equipment. It is designed for applications with partial vacuums and requires little space for installation and infrequent servicing.

  8. Structural Design and Sealing Performance Analysis of Biomimetic Sealing Ring

    PubMed Central

    Han, Chuanjun

    2015-01-01

    In order to reduce the failure probability of rubber sealing rings in reciprocating dynamic seal, a new structure of sealing ring based on bionics was designed. The biomimetic ring has three concave ridges and convex bulges on each side which are very similar to earthworms. Bulges were circularly designed and sealing performances of the biomimetic ring in both static seal and dynamic seal were simulated by FEM. In addition, effects of precompression, medium pressure, speed, friction coefficient, and material parameters on sealing performances were discussed. The results show that von Mises stress of the biomimetic sealing ring distributed symmetrically in no-pressure static sealing. The maximum von Mises stress appears on the second bulge of the inner side. High contact stress concentrates on left bulges. Von Mises stress distribution becomes uneven under medium pressure. Both von Mises stress and contact stress increase when precompression, medium pressure, and rubber hardness increase in static sealing. Biomimetic ring can avoid rolling and distortion in reciprocating dynamic seal, and its working life is much longer than O-ring and rectangular ring. The maximum von Mises stress and contact stress increase with the precompression, medium pressure, rubber hardness, and friction coefficient in reciprocating dynamic seal. PMID:27019582

  9. Structural Design and Sealing Performance Analysis of Biomimetic Sealing Ring.

    PubMed

    Han, Chuanjun; Zhang, Han; Zhang, Jie

    2015-01-01

    In order to reduce the failure probability of rubber sealing rings in reciprocating dynamic seal, a new structure of sealing ring based on bionics was designed. The biomimetic ring has three concave ridges and convex bulges on each side which are very similar to earthworms. Bulges were circularly designed and sealing performances of the biomimetic ring in both static seal and dynamic seal were simulated by FEM. In addition, effects of precompression, medium pressure, speed, friction coefficient, and material parameters on sealing performances were discussed. The results show that von Mises stress of the biomimetic sealing ring distributed symmetrically in no-pressure static sealing. The maximum von Mises stress appears on the second bulge of the inner side. High contact stress concentrates on left bulges. Von Mises stress distribution becomes uneven under medium pressure. Both von Mises stress and contact stress increase when precompression, medium pressure, and rubber hardness increase in static sealing. Biomimetic ring can avoid rolling and distortion in reciprocating dynamic seal, and its working life is much longer than O-ring and rectangular ring. The maximum von Mises stress and contact stress increase with the precompression, medium pressure, rubber hardness, and friction coefficient in reciprocating dynamic seal. PMID:27019582

  10. Physical properties of Dowell Chemical Seal Ring

    SciTech Connect

    Benny, H.L.

    1985-07-01

    This document outlines the tests, procedures, and results of an evaluation program for Dowell's Chemical Seal Ring.'' The testing reported here deals with the physical properties of density, compression, tensile strength, elongation, and a push-out/bond strength test. Dowell's Chemical Seal Ring'' is proposed as a gasket-like seal between grout layers in the annulus around the Exploratory Shaft steel liner. 4 refs., 1 fig., 4 tabs.

  11. Sealed and lubricated rock bit with air protected seal ring

    SciTech Connect

    Galle, E.M.

    1983-03-01

    An earth boring rock bit having a sealed bearing and pressure lubrication system for drilling the earth with air or gas as the circulating medium. An annular groove is formed in the vicinity of the seal and connected to the interior of the bit for cooling the ring and cleaning debris from the area of the ring. The air pressure inside the bit is utilized to bias a movable element in the system to urge lubricant to the bearing.

  12. Low thermal expansion seal ring support

    DOEpatents

    Dewis, David W.; Glezer, Boris

    2000-01-01

    Today, the trend is to increase the temperature of operation of gas turbine engines. To cool the components with compressor discharge air, robs air which could otherwise be used for combustion and creates a less efficient gas turbine engine. The present low thermal expansion sealing ring support system reduces the quantity of cooling air required while maintaining life and longevity of the components. Additionally, the low thermal expansion sealing ring reduces the clearance "C","C'" demanded between the interface between the sealing surface and the tip of the plurality of turbine blades. The sealing ring is supported by a plurality of support members in a manner in which the sealing ring and the plurality of support members independently expand and contract relative to each other and to other gas turbine engine components.

  13. An Internal Coaxil Cable Seal System

    DOEpatents

    Hall, David R.; Hall, Jr., H. Tracy; Pixton, David; Dahlgren, Scott; Sneddon, Cameron; Briscoe, Michael; Fox, Joe

    2004-12-23

    The invention is a seal system for a coaxial cable more specifically an internal seal system placed within the coaxial cable and its constituent components. A series of seal stacks including flexible rigid rings and elastomeric rings are placed on load bearing members within the coaxial cable. The current invention is adapted to seal the annular space between the coaxial cable and an electrical contact passing there through. The coaxial cable is disposed within drilling components to transmit electrical signals between drilling components within a drill string. During oil and gas exploration, a drill string can see a range of pressures and temperatures thus resulting in multiple combinations of temperature and pressure and increasing the difficulty of creating a robust seal for all combinations. The seal system can be used in a plurality of downhole components, such as sections of pipe in a drill string, drill collars, heavy weight drill pipe, and jars.

  14. Internal coaxial cable seal system

    DOEpatents

    Hall, David R.; Sneddon, Cameron; Dahlgren, Scott Steven; Briscoe, Michael A.

    2006-07-25

    The invention is a seal system for a coaxial cable and is placed within the coaxial cable and its constituent components. A series of seal stacks including load ring components and elastomeric rings are placed on load bearing members within the coaxial cable sealing the annular space between the coaxial cable and an electrical contact passing there through. The coaxial cable is disposed within drilling components to transmit electrical signals between drilling components within a drill string. The seal system can be used in a variety of downhole components, such as sections of pipe in a drill string, drill collars, heavy weight drill pipe, and jars.

  15. Mechanical seal having a double-tier mating ring

    DOEpatents

    Khonsari, Michael M.; Somanchi, Anoop K.

    2005-09-13

    An apparatus and method to enhance the overall performance of mechanical seals in one of the following ways: by reducing seal face wear, by reducing the contact surface temperature, or by increasing the life span of mechanical seals. The apparatus is a mechanical seal (e.g., single mechanical seals, double mechanical seals, tandem mechanical seals, bellows, pusher mechanical seals, and all types of rotating and reciprocating machines) comprising a rotating ring and a double-tier mating ring. In a preferred embodiment, the double-tier mating ring comprises a first and a second stationary ring that together form an agitation-inducing, guided flow channel to allow for the removal of heat generated at the seal face of the mating ring by channeling a coolant entering the mating ring to a position adjacent to and in close proximity with the interior surface area of the seal face of the mating ring.

  16. Pressure-Energized Seal Rings to Better Withstand Flows

    NASA Technical Reports Server (NTRS)

    Farner, Bruce

    2009-01-01

    Pressure-energized seal rings intended to withstand flows better than do conventional pressure-energized seal rings have been conceived. The concept applies, more specifically, to seal rings used on some valve stems, pistons, and the like. A conventional pressure-energized seal ring generally has a U-shaped cross section and consists of an elastomer or other suitable polymer with an embedded metal energizing spring (see Figure 1). The working fluid from the high-pressure side that one seeks to seal is allowed into the U-shaped cavity, so that the pressure pushes the sides of the seal ring tighter against the gland and body sealing surfaces, thereby increasing the degree of sealing. Unfortunately, when the seal ring is exposed to flow of the working fluid, under some conditions, the flow grabs the lip of the U-shaped cross section and ejects or deforms the seal ring so that, thereafter, a proper seal is not obtained. Figure 2 depicts one of several alternative seal rings according to the present concept. One element of the concept is to modify the U-shaped cross section from that of the corresponding conventional seal ring to eliminate the exposed lip and prevent entry of the working fluid into the U-shaped cavity. Unlike in the conventional seal, pressurized fluid would not push the seal ring directly against the both gland and body sealing surfaces. Instead, the pressure would directly push the seal ring against a gland sealing surface only. In so doing, the pressure would squash the seal ring into a smaller volume bounded by the gland and body sealing surfaces, and would thereby indirectly press the seal ring more tightly against the body sealing surface. To enhance the desired squashing deformation, a spring having an approximately parallelogram cross section would be embedded in the modified U-shaped cavity. As the pressure pushed two corners of the approximate parallelogram closer together along the axis of the seal ring, the other two corners of the

  17. Mechanical seal having a single-piece, perforated mating ring

    DOEpatents

    Khonsari, Michael M.; Somanchi, Anoop K.

    2007-08-07

    A mechanical seal (e.g., single mechanical seals, double mechanical seals, tandem mechanical seals, bellows, pusher mechanical seals, and all types of rotating and reciprocating machines) with reduced contact surface temperature, reduced contact surface wear, or increased life span. The mechanical seal comprises a rotating ring and a single-piece, perforated mating ring, which improves heat transfer by controllably channeling coolant flow through the single-piece mating ring such that the coolant is in substantially uniform thermal contact with a substantial portion of the interior surface area of the seal face, while maintaining the structural integrity of the mechanical seal and minimizing the potential for coolant flow interruptions to the seal face caused by debris or contaminants (e.g., small solids and trash) in the coolant.

  18. Multiple internal seal right micro-electro-mechanical system vacuum package

    NASA Technical Reports Server (NTRS)

    Hayworth, Ken J. (Inventor); Yee, Karl Y. (Inventor); Shcheglov, Kirill V. (Inventor); Bae, Youngsam (Inventor); Wiberg, Dean V. (Inventor); Challoner, A. Dorian (Inventor); Peay, Chris S. (Inventor)

    2007-01-01

    A Multiple Internal Seal Ring (MISR) Micro-Electro-Mechanical System (MEMS) vacuum package that hermetically seals MEMS devices using MISR. The method bonds a capping plate having metal seal rings to a base plate having metal seal rings by wafer bonding the capping plate wafer to the base plate wafer. Bulk electrodes may be used to provide conductive paths between the seal rings on the base plate and the capping plate. All seals are made using only metal-to-metal seal rings deposited on the polished surfaces of the base plate and capping plate wafers. However, multiple electrical feed-through metal traces are provided by fabricating via holes through the capping plate for electrical connection from the outside of the package through the via-holes to the inside of the package. Each metal seal ring serves the dual purposes of hermetic sealing and providing the electrical feed-through metal trace.

  19. Operating aspects of an oil pumping ring seal

    NASA Technical Reports Server (NTRS)

    Smith, P. J.; Keith, T. G., Jr.

    1986-01-01

    Past analyses have left several unanswered questions regarding the operation of a pumping ring seal. This paper addresses some of these unresolved problems. In particular, treatment of the film-ring interfacial boundary condition and the return portion of the pumping cycle are numerically investigated. Further a simple model is proposed to determine whether or not the seal operates fully flooded.

  20. Improved internal seals for pipeline centrifugal compressors

    SciTech Connect

    Shapiro, W.; Lee, C.

    1988-05-31

    Internal labyrinth seals are used extensively in pipeline compressors as impeller inlet seals, interstage seals, and balance piston seals (for beam-type machines). The purposes of this program were to determine the effects on compressor performance of internal seal leakage, consider variations in labyrinth configurations to improve performance, and determine the feasibility of other types of seals that might provide improved performance. In addition, rotordynamic studies of an overhung machine were conducted to establish whether unbalance response was sufficient to cause seal contact and consequent wear. The program involved consultation with both users and manufacturers of pipeline compressors to obtain information regarding the nature of problems, description of the machinery and seal configurations, operating conditions, contemporary design procedures, and advanced seal developments. The results indicated that internal leakage can significantly reduce compressor efficiency; in some machines as much as 3 to 6%, depending on seal clearance. Optimized step seal geometries will provide improved performance, especially for seals that have worn from rubbing contact. A principal problem is seal wear that results from compressor surge. During normal operation, impeller motions are constrained within seal clearances, but when surge occurs severe rubbing can take place. Abradable seals do not address the surge wear problem, except that wear may take longer since abradable seals start out with tighter clearances. A variety of advanced concepts were considered. The most promising are resilient labyrinths that can elastically respond to impeller movements created by compressor surge without excessive damage or wear. 10 refs., 74 figs., 24 tabs.

  1. Monitoring Snow on ice as Critical Habitat for Ringed Seals

    NASA Astrophysics Data System (ADS)

    Kelly, B. P.; Moran, J.; Douglas, D. C.; Nghiem, S. V.

    2007-12-01

    Ringed seals are the primary prey of polar bears, and they are found in all seasonally ice covered seas of the northern hemisphere as well as in several freshwater lakes. The presence of snow covered sea ice is essential for successful ringed seal reproduction. Ringed seals abrade holes in the ice allowing them to surface and breathe under the snow cover. Where snow accumulates to sufficient depths, ringed seals excavate subnivean lairs above breathing holes. They rest, give birth, and nurse their young in those lairs. Temperatures within the lairs remain within a few degrees of freezing, well within the zone of thermal neutrality for newborn ringed seals, even at ambient temperatures of -30° C. High rates of seal mortality have been recorded when early snow melt caused lairs to collapse exposing newborn seals to predators and to subsequent extreme cold events. As melt onset dates come earlier in the Arctic Ocean, ringed seal populations (and the polar bears that depend upon them) will be increasingly challenged. We determined dates of lair abandonment by ringed seals fitted with radio transmitters in the Beaufort Sea (n = 60). We compared abandonment dates to melt onset dates measured in the field, as well as estimated dates derived from active (Ku-band backscatter) and passive (SSM/I) microwave satellite imagery. Date of snow melt significantly improved models of environmental influences on the timing of lair abandonment. We used an algorithm based on multi-channel means and variances of passive microwave data to detect melt onset dates. Those melt onset dates predicted the date of lair abandonment ± 3 days (r 2 = 0.982, p = 0.001). The predictive power of passive microwave proxies combined with their historical record suggest they could serve to monitor critical changes to ringed seal habitat.

  2. O-ring sealing verification for the space shuttle redesign solid rocket motor

    NASA Technical Reports Server (NTRS)

    Lach, Cynthia L.

    1989-01-01

    As a part of the redesign of the Space Shuttle Solid Rocket Motor, the field and nozzle-to-case joints were redesigned to minimize the dynamic flexure caused by internal motor pressurization during ignition. The O-ring seals and glands for the joints were designed to accommodate both structural deflections and to promote pressure assistance. A test program was conducted to determine if a fluorocarbon elastomeric O-ring could meet this criteria in the redesigned gland. Resiliency tests were used to investigate the O-ring response to gap motion while static seal tests were used to verify design criteria of pressure assistance for sealing. All tests were conducted in face seal fixtures mounted in servo-hydraulic test machines. The resiliency of the O-ring was found to be extremely sensitive to the effects of temperature. The External Tank/Solid Rocket Booster attach strut loads had a negligible affect on the ability of the O-ring to track the simulated SRB field joint deflection. In the static pressure-assisted seal tests, as long as physical contact was maintained between the O-ring and the gland sealing surface, pressure assistance induced instantaneous sealing.

  3. SRB attach ring phenolic TPS fishtail seal evaluation tests

    NASA Technical Reports Server (NTRS)

    Karu, Z. S.

    1982-01-01

    The SRB attach ring is thermally protected with layered phenolic cloth fairings that are fastened to the ring. The gap between the fairings and the motor case is closed off with a rubber seal of a fishtail cross sectional shape bonded to the phenolic. On both the STS-1 and STS-2 flights this gap was discovered to vary anywhere from an intended gap of 0.375 in. to an actual measured gap of 0.60 in. due to tolerances. Tests were conducted with and without a 0.25 in. thick cork shim placed under the seal with a 0.60 in. gap under the phenolic TPS to determine and compare the performance of the seal in the two different configurations. To alleviate the difficult and costly procedure of installing the cork shim under the seal, especially after phenolic TPS mounting on the attach ring, large fishtail seals of idential Elder gray silicon material and two different hardnesses were tested. A similar matrix of tests was conducted with this new large fishtail seal, and seals with both type hardnesses performed well regardless of whether or not the seal was bonded in the phenolic at the front of the seal groove. Similar results had been obtained with the original small fishtail seal which performed adequately with the 0.25 in. cork shim under it.

  4. Effect of temperature and O-ring gland finish on sealing ability of Viton V747-75

    NASA Technical Reports Server (NTRS)

    Lach, Cynthia L.

    1993-01-01

    As a part of the redesign project of the Space Shuttle solid rocket motor (SRM) following the Challenger accident, the field joint was redesigned to minimize the relative joint motion caused by internal motor pressurization during ignition. The O-ring seals and glands for the field joint were designed both to accommodate structural deflections and to promote pressure-assisted sealing. Tests were conducted in various face seal fixtures to evaluate the ability of Viton V747-75 O-rings to seal for a range of temperatures and surface finishes of the redesigned O-ring gland. The effect of surface finish on the sealing performance and wear characteristics of the O-rings was evaluated during simulated launch conditions that included low-frequency vibrations, gap openings, and rapid pressurizations. The effect of contamination on the sealing performance was also investigated. The O-rings sealed throughout the 75 deg F leak check test and for the seal tests from 50 deg F to 120 deg F for the range of surface finishes investigated. Although abrasions were found in the O-rings from pressurization against the rougher finishes, these abrasions were not detrimental to sealing. Below 50 deg F, Viton V747-75 O-rings were insufficiently resilient to track the test gap opening.

  5. Design analysis of a self-acting spiral-groove ring seal for counter-rotating shafts. [o ring seals

    NASA Technical Reports Server (NTRS)

    Di Russo, EL

    1983-01-01

    A self-acting spiral groove inter-shaft ring seal of nominal 16.33 cm (6.43 in.) diameter for sealing fan bleed air between counter rotating shafts in advanced turbofan engines was analyzed. The analysis focused on the lift force characteristics of the spiral grooves. A NASA Lewis developed computer program for predicting the performance of gas lubricated face seals was used to optimize the spiral groove geometry to produce maximum lift force. Load capacity curves (lift force as function of film thickness) were generated for four advanced turbofan engine operating conditions at relative seal speeds ranging from 17,850 to 29,800 rpm, sealed air pressures from 6 to 42 N/sq cm (9 to 60 Psi) absolute and temperatures from 95 to 327 C (203 to 620 F). The relative seal sliding speed range was 152 to 255 m/sec (500 to 836 ft/sec). The analysis showed that the spiral grooves are capable of producing sufficient lift force such that the ring seal will operate in a noncontacting mode over the operating range of typical advanced turbofan engines. Previously announced in STAR as N83-23306

  6. Seasonal Activity Budget of Adult Baltic Ringed Seals

    PubMed Central

    Harkonen, Tero; Jüssi, Mart; Jüssi, Ivar; Verevkin, Michail; Dmitrieva, Lilia; Helle, Eero; Sagitov, Roustam; Harding, Karin C.

    2008-01-01

    Although ringed seals are important components in oceanic and fresh water ecosystems at high latitudes, little is known about how they exploit these harsh environments. Seasonal activity and diving behaviour of 19 adult Baltic ringed seals were studied by satellite telemetry. We elaborated an activity budget for ten months of the year, extending over the period from moult to the breeding season. Seals from three main regions showed explicit site fidelity and the distributions of animals tagged from different areas did not overlap, suggesting separate stocks. Both the mean duration and the mean depth of dives peaked in June and July. Seals spent 70% (females) to 85% (males) of their time diving in June and July which decreased to 50% in late autumn. Less than one percent of dives exceeded 10 min in females, while 10% of male dives lasted longer than 10 min in June to September. Less than one percent of dives lasted for more than 25 min. Both females and males were most active during day time and hauled out predominantly during the night. Activity patterns during the summer are suggested to be correlated to energy accumulation and prey availability. The information on seasonal activity budget is crucial for developing population energetic models where interactions between ringed seals and other trophic levels can be evaluated. PMID:18414676

  7. Fluorocarbon seal replaces metal piston ring in low density gas environment

    NASA Technical Reports Server (NTRS)

    Morath, W. D.; Morgan, N. E.

    1967-01-01

    Reinforced fluorocarbon cupseal, which provides an integral lip-type seal, replaces the metal piston rings in piston-cylinder configurations used in the compression of low density gases. The fluorocarbon seal may be used as cryogenic compressor piston seals.

  8. O-ring sealing arrangements for ultra-high vacuum systems

    SciTech Connect

    Flaherty, R.; Kim, C.

    1981-08-04

    An all metal reusable o-ring sealing arrangement is disclosed for sealing two concentric tubes in an ultra-high vacuum system. An o-ring of a heat recoverable alloy such as nitinol is concentrically positioned between protruding sealing rings of the concentric tubes. The o-ring is installed between the tubes while in a stressed martensitic state and is made to undergo a thermally induced transformation to an austenitic state. During the transformation the o-ring expands outwardly and contracts inwardly toward a previously sized austenitic configuration, thereby sealing against the protruding sealing rings of the concentric tubes.

  9. O-Ring sealing arrangements for ultra-high vacuum systems

    DOEpatents

    Kim, Chang-Kyo; Flaherty, Robert

    1981-01-01

    An all metal reusable O-ring sealing arrangement for sealing two concentric tubes in an ultra-high vacuum system. An O-ring of a heat recoverable alloy such as Nitinol is concentrically positioned between protruding sealing rings of the concentric tubes. The O-ring is installed between the tubes while in a stressed martensitic state and is made to undergo a thermally induced transformation to an austenitic state. During the transformation the O-ring expands outwardly and contracts inwardly toward a previously sized austenitic configuration, thereby sealing against the protruding sealing rings of the concentric tubes.

  10. Permanent seal ring for a nuclear reactor cavity

    SciTech Connect

    Hankinson, M.F.; Marshall, J.R.

    1988-05-31

    A nuclear reactor containment arrangement is described including: a. a reactor vessel which thermally expands and contracts during cyclic operation of the reactor and which has a peripheral wall; b. a containment wall spaced apart from and surrounding the peripheral wall of the reactor vessel and defining an annular thermal expansion gap therebetween for accommodating thermal expansion; and c. an annular ring seal which sealingly engages and is affixed to and extends between the peripheral wall of the reactor vessel and the containment wall.

  11. Influence analysis of secondary O-ring seals in dynamic behavior of spiral groove gas face seals

    NASA Astrophysics Data System (ADS)

    Hu, Songtao; Huang, Weifeng; Liu, Xiangfeng; Wang, Yuming

    2016-05-01

    The current research on secondary O-ring seals used in mechanical seals has begun to focus on their dynamic properties. However, detailed analysis of the dynamic properties of O-ring seals in spiral groove gas face seals is lacking. In particular a transient study and a difference analysis of steady-state and transient performance are imperative. In this paper, a case study is performed to gauge the effect of secondary O-ring seals on the dynamic behavior (steady-state performance and transient performance) of face seals. A numerical finite element method (FEM) model is developed for the dynamic analysis of spiral groove gas face seals with a flexibly mounted stator in the axial and angular modes. The rotor tilt angle, static stator tilt angle and O-ring damping are selected to investigate the effect of O-ring seals on face seals during stable running operation. The results show that the angular factor can be ignored to save time in the simulation under small damping or undamped conditions. However, large O-ring damping has an enormous effect on the angular phase difference of mated rings, affecting the steady-state performance of face seals and largely increasing the possibility of face contact that reduces the service life of face seals. A pressure drop fluctuation is carried out to analyze the effect of O-ring seals on the transient performance of face seals. The results show that face seals could remain stable without support stiffness and O-ring damping during normal stable operation but may enter a large-leakage state when confronting instantaneous fluctuations. The oscillation-amplitude shortening effect of O-ring damping on the axial mode is much greater than that on the angular modes and O-ring damping prefers to cater for axial motion at the cost of angular motion. This research proposes a detailed dynamic-property study of O-ring seals in spiral groove gas face seals, to assist in the design of face seals.

  12. Influence analysis of secondary O-ring seals in dynamic behavior of spiral groove gas face seals

    NASA Astrophysics Data System (ADS)

    Hu, Songtao; Huang, Weifeng; Liu, Xiangfeng; Wang, Yuming

    2016-04-01

    The current research on secondary O-ring seals used in mechanical seals has begun to focus on their dynamic properties. However, detailed analysis of the dynamic properties of O-ring seals in spiral groove gas face seals is lacking. In particular a transient study and a difference analysis of steady-state and transient performance are imperative. In this paper, a case study is performed to gauge the effect of secondary O-ring seals on the dynamic behavior (steady-state performance and transient performance) of face seals. A numerical finite element method (FEM) model is developed for the dynamic analysis of spiral groove gas face seals with a flexibly mounted stator in the axial and angular modes. The rotor tilt angle, static stator tilt angle and O-ring damping are selected to investigate the effect of O-ring seals on face seals during stable running operation. The results show that the angular factor can be ignored to save time in the simulation under small damping or undamped conditions. However, large O-ring damping has an enormous effect on the angular phase difference of mated rings, affecting the steady-state performance of face seals and largely increasing the possibility of face contact that reduces the service life of face seals. A pressure drop fluctuation is carried out to analyze the effect of O-ring seals on the transient performance of face seals. The results show that face seals could remain stable without support stiffness and O-ring damping during normal stable operation but may enter a large-leakage state when confronting instantaneous fluctuations. The oscillation-amplitude shortening effect of O-ring damping on the axial mode is much greater than that on the angular modes and O-ring damping prefers to cater for axial motion at the cost of angular motion. This research proposes a detailed dynamic-property study of O-ring seals in spiral groove gas face seals, to assist in the design of face seals.

  13. Wafer-level packaging with compression-controlled seal ring bonding

    SciTech Connect

    Farino, Anthony J

    2013-11-05

    A device may be provided in a sealed package by aligning a seal ring provided on a first surface of a first semiconductor wafer in opposing relationship with a seal ring that is provided on a second surface of a second semiconductor wafer and surrounds a portion of the second wafer that contains the device. Forcible movement of the first and second wafer surfaces toward one another compresses the first and second seal rings against one another. A physical barrier against the movement, other than the first and second seal rings, is provided between the first and second wafer surfaces.

  14. Giardia duodenalis and Cryptosporidium spp. in the intestinal contents of ringed seals (Phoca hispida) and bearded seals (Erignathus barbatus) in Nunavik, Quebec, Canada.

    PubMed

    Dixon, Brent R; Parrington, Lorna J; Parenteau, Monique; Leclair, Daniel; Santín, Mónica; Fayer, Ronald

    2008-10-01

    The prevalence of Giardia duodenalis and Cryptosporidium spp. was determined for ringed and bearded seals harvested for food in the Nunavik region in northern Quebec, Canada. Flow cytometric results demonstrated that G. duodenalis was present in the intestinal contents of 80% of the ringed seals and 75% of the bearded seals tested, while Cryptosporidium spp. were present in 9% of the ringed seals and none of the bearded seals. Prevalence of both parasites was highest in animals less than 1 yr of age. Giardia sp. isolates from ringed seals were identified as G. duodenalis Assemblage B, which is commonly identified in human infections. The high prevalence of G. duodenalis in ringed seals, and the presence of Assemblage B in these animals, highlights the potential for zoonotic transmission to the Inuit people, who consume dried seal intestines and uncooked seal meat. PMID:18576814

  15. Design improvement of a pump wear ring labyrinth seal

    NASA Technical Reports Server (NTRS)

    Rhode, David L.; Morrison, G. L.; Ko, S. H.; Waughtal, S. P.

    1987-01-01

    The investigation was successful in obtaining two improved designs for the impeller wear ring seal of the liquid hydrogen turbopump of interest. A finite difference computer code was extensively used in a parametric computational study in determining a cavity configuration with high flow resistance due to turbulence dissipation. These two designs, along with that currently used, were fabricated and tested. The improved designs were denoted Type O and Type S. The measurements showed that Type O and Type S given 67 and 30 percent reduction in leakage over the current design, respectively. It was found that the number of cavities, the step height and the presence of a small stator groove are quite important design features. Also, the tooth thickness is of some significance. Finally, the tooth height and an additional large cavity cut out from the stator (upstream of the step) are of negligible importance.

  16. Genetic characterization of Cryptosporidium isolates from ringed seals (Phoca hispida) in Northern Quebec, Canada.

    PubMed

    Santín, Mónica; Dixon, Brent R; Fayert, Ronald

    2005-06-01

    This study reports the molecular characterization of Cryptosporidium spp. isolates identified from intestinal contents of ringed seals (Phoca hispida) from Nunavik (Quebec, Canada). Cryptosporidium spp. fragments of 18S rRNA, HSP-70, and actin loci were amplified by PCR from seal intestinal contents. PCR-positive specimens were sequenced and compared with other Cryptosporidium species and genotypes reported previously. Sequence analysis showed the presence of C. muris and 2 novel genotypes in ringed seals. PMID:16108576

  17. High-Pressure Hot-Gas Self-Acting Floating Ring Shaft Seal for Liquid Rocket Turbopumps. [tapered bore seals

    NASA Technical Reports Server (NTRS)

    Burcham, R. E.; Diamond, W. A.

    1980-01-01

    Design analysis, detail design, fabrication, and experimental evaluation was performed on two self acting floating ring shaft seals for a rocket engine turbopump high pressure 24132500 n/sq m (3500 psig) hot gas 533 K 9500 F) high speed 3142 rad/sec (30000 rmp) turbine. The initial design used Rayleigh step hydrodynamic lift pads to assist in centering the seal ring with minimum rubbing contact. The final design used a convergent tapered bore to provide hydrostatic centering force. The Rayleigh step design was tested for 107 starts and 4.52 hours total. The leakage was satisfactory; however, the design was not acceptable due to excessive wear caused by inadequate centering force and failure of the sealing dam caused by erosion damage. The tapered bore design was tested for 370 starts and 15.93 hours total. Satisfactory performance for the required life of 7.5 hours per seal was successfully demonstrated.

  18. Amphibious hearing in ringed seals (Pusa hispida): underwater audiograms, aerial audiograms and critical ratio measurements.

    PubMed

    Sills, Jillian M; Southall, Brandon L; Reichmuth, Colleen

    2015-07-01

    Ringed seals (Pusa hispida) are semi-aquatic marine mammals with a circumpolar Arctic distribution. In this study, we investigate the amphibious hearing capabilities of ringed seals to provide auditory profiles for this species across the full range of hearing. Using psychophysical methods with two trained ringed seals, detection thresholds for narrowband signals were measured under quiet, carefully controlled environmental conditions to generate aerial and underwater audiograms. Masked underwater thresholds were measured in the presence of octave-band noise to determine critical ratios. Results indicate that ringed seals possess hearing abilities comparable to those of spotted seals (Phoca largha) and harbor seals (Phoca vitulina), and considerably better than previously reported for ringed and harp seals. Best sensitivity was 49 dB re. 1 µPa (12.8 kHz) in water, and -12 dB re. 20 µPa (4.5 kHz) in air, rivaling the acute hearing abilities of some fully aquatic and terrestrial species in their respective media. Critical ratio measurements ranged from 14 dB at 0.1 kHz to 31 dB at 25.6 kHz, suggesting that ringed seals--like other true seals--can efficiently extract signals from background noise across a broad range of frequencies. The work described herein extends similar research on amphibious hearing in spotted seals recently published by the authors. These parallel studies enhance our knowledge of the auditory capabilities of ice-living seals, and inform effective management strategies for these and related species in a rapidly changing Arctic environment. PMID:25987727

  19. Microsatellite variation in ringed seals (Phoca hispida): genetic structure and history of the Baltic Sea population.

    PubMed

    Palo, J U; Mäkinen, H S; Helle, E; Stenman, O; Väinölä, R

    2001-05-01

    Genetic variability and population structure of Baltic ringed seals and an Arctic reference population were assessed using eight microsatellite loci. Ringed seals colonized the Baltic Sea basin soon after deglaciation 11 500 years ago and are supposed to have remained largely isolated from the main Arctic stock since then, approximately 1000 generations. In the 1900s the Baltic population declined rapidly, and is now confined to three distinct breeding areas, with N < 6000 seals altogether. Microsatellite heterozygosity in ringed seals was higher than that in the closely related, boreal harbour seal and grey seal, for which the markers were initially developed. This is plausibly attributed to an overall greater population (species) size of ringed seals during the Quaternary. Allele frequency differentiation between the Baltic and Arctic ringed seals, conventionally treated as different subspecies, was weak. Assuming complete isolation, the divergence (FST=0.023) would imply a notably high postglacial effective population size, approximately 20 000 for the Baltic population. The isolation assumption however, seems unrealistic in the light of the data: a coalescent-based simulation approach to the likelihood of alternative demographic histories clearly favoured a scenario with recurrent gene flow to the Baltic, over one of complete isolation (drift only). Within the Baltic Sea, no differentiation was found between the Gulf of Finland and the Gulf of Bothnia breeding areas; the recent population decline and split have not yet affected the inbreeding levels of the disjunct breeding stocks. PMID:11554977

  20. Leakage test concerns for packagings with three-O-ring closure seals

    SciTech Connect

    Oras, J.J.; Towell, R.H.; Wangler, M.E.

    1997-07-01

    Recent radioactive packagings with three-O-ring closure seals, the middle O-ring being the containment seal, have the potential for false positive results from leakage rate tests. The volume between the containment O-ring and the inner O-ring is used for the helium gas required for the leakage rate tests, to reduce both the amount of helium used and the time for the tests. False positive results can be caused by either a large leakage in the containment sea/l or a leakage in the inner seal. This paper describes the problem, together with possible solutions/areas that need to be addressed in a Safety Analysis Report for Packaging.

  1. Dynamic valve seal is reliable at cryogenic temperatures

    NASA Technical Reports Server (NTRS)

    Moxley, H. E.

    1967-01-01

    C-shaped PTFE /polytetrafluorethylene/ seal ring provides a reliable seal in cryogenic fluids over a fluid pressure range of 0 to 2000 psig. It is interference-fitted internally with a metal expander ring and a metal compressor ring.

  2. Split ring floating air riding seal for a turbine

    DOEpatents

    Mills, Jacob A

    2015-11-03

    A floating air riding seal for a gas turbine engine with a rotor and a stator, an annular piston chamber with an axial moveable annular piston assembly within the annular piston chamber, an annular cavity formed on the annular piston assembly that faces a seal surface on the rotor, and a central passage connecting the annular cavity to the annular piston chamber to supply compressed air to the seal face, where the annular piston assembly is a split piston assembly to maintain a tight seal as coning of the rotor disk occurs.

  3. Fluid-solid interaction model for hydraulic reciprocating O-ring seals

    NASA Astrophysics Data System (ADS)

    Liao, Chuanjun; Huang, Weifeng; Wang, Yuming; Suo, Shuangfu; Liu, Ying

    2013-01-01

    Elastohydrodynamic lubrication characteristics of hydraulic reciprocating seals have significant effects on sealing and tribology performances of hydraulic actuators, especially in high parameter hydraulic systems. Only elastic deformations of hydraulic reciprocating seals were discussed, and hydrodynamic effects were neglected in many studies. The physical process of the fluid-solid interaction effect did not be clearly presented in the existing fluid-solid interaction models for hydraulic reciprocating O-ring seals, and few of these models had been simultaneously validated through experiments. By exploring the physical process of the fluid-solid interaction effect of the hydraulic reciprocating O-ring seal, a numerical fluid-solid interaction model consisting of fluid lubrication, contact mechanics, asperity contact and elastic deformation analyses is constructed with an iterative procedure. With the SRV friction and wear tester, the experiments are performed to investigate the elastohydrodynamic lubrication characteristics of the O-ring seal. The regularity of the friction coefficient varying with the speed of reciprocating motion is obtained in the mixed lubrication condition. The experimental result is used to validate the fluid-solid interaction model. Based on the model, The elastohydrodynamic lubrication characteristics of the hydraulic reciprocating O-ring seal are presented respectively in the dry friction, mixed lubrication and full film lubrication conditions, including of the contact pressure, film thickness, friction coefficient, liquid film pressure and viscous shear stress in the sealing zone. The proposed numerical fluid-solid interaction model can be effectively used to analyze the operation characteristics of the hydraulic reciprocating O-ring seal, and can also be widely used to study other hydraulic reciprocating seals.

  4. Trends of perfluorochemicals in Greenland ringed seals and polar bears: indications of shifts to decreasing trends.

    PubMed

    Rigét, Frank; Bossi, Rossana; Sonne, Christian; Vorkamp, Katrin; Dietz, Rune

    2013-11-01

    Time-series of perfluorinated alkylated substances (PFASs) in East Greenland polar bears and East and West Greenland ringed seals were updated in order to deduce whether a response to the major reduction in perfluoroalkyl production in the early 2000s had occurred. Previous studies had documented an exponential increase of perfluorooctane sulphonate (PFOS) in liver tissue from both species. In the present study, PFOS was still the far most dominant compound constituting 92% (West Greenland ringed seals), 88% (East Greenland ringed seals) and 85% (East Greenland polar bears). The PFOS concentrations increased up to 2006 with doubling times of approximately 6 years for the ringed seal populations and 14 years in case of polar bears. Since then a rapid decrease has occurred with clearing half-lives of approximately 1, 2 and 4 years, respectively. In polar bears perfluorohexane sulphonate (PFHxS) and perfluorooctane sulphonamide (PFOSA) also showed decreasing trends in recent years as do perfluorodecanoic acid (PFDA) and perfluoroundecanoic acid (PFUnA). For the West Greenland ringed seal population perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), PFDA and PFUnA peaked in the mid 2000s, whereas PFNA, PFDA and PFUnA in the East Greenland population have been stable or increasing in recent years. The peak of PFASs in Greenland ringed seals and polar bears occurred at a later time than in Canadian seals and polar bears and considerably later than observed in seal species from more southern latitudes. We suggest that this could be explained by the distance to emission hot-spots and differences in long-range transport to the Arctic. PMID:24025534

  5. Automated Inspection of the RSRM Case O-Ring Seal Surface

    NASA Technical Reports Server (NTRS)

    ODell, Keith P.; McCool, Alex (Technical Monitor)

    2001-01-01

    An automated inspection system has been developed to inspect the o-ring sealing surfaces on the Space Shuttle reusable solid rocket motor (RSRM) case segment joints. A laser digitizing system is used to create a three dimensional map of the o-ring sealing surfaces. This data is analyzed for any irregularities, which are noted for further inspection and disposition. This paper describes both the hardware and the software used to gather data as well as the methods developed to analyze the data. The RSRM is assembled from four casting segments. Each of the field joints between these segments is sealed with three o-rings. These o-rings are critical for the proper operation of the motor. After launch the booster segments are recovered and reused. As part of the refurbishment process the o-ring sealing surfaces are inspected for any irregularities. The system developed uses a combination of commercial and customized hardware and software. The system uses two computer systems in a real time environment to control a laser, an XYZ precision table, and case rotation and position information. The system is capable of inspecting both the tang end and the clevis end of the RSRM field joint. The o-ring grooves and flat sealing surfaces are inspected.

  6. Leakage testing of packagings with three-O-ring closure seals

    SciTech Connect

    Oras, J.J.; Towell, R.H.; Wangler, M.E.

    1997-10-01

    Both the American National Standard for Radioactive Materials--Leakage Tests on Packages for Shipment (ANSI N14.5) and the ISO 12807:1996 Safe Transport of Radioactive Materials--Leakage Testing on Packages provide guidance for leakage rate testing to show that a particular packaging complies with regulatory requirements; both also provide guidance for determining appropriate acceptance criteria. Recent radioactive packaging designs have incorporated three-O-ring closure seals, the middle O-ring being the containment seal. These designs have the potential for false positive results in leakage rate tests. The volume between the containment O-ring and the inner O-ring is used for the helium gas required for the leakage rate tests, in order to reduce both the amount of helium used and the time required to conduct the tests. A leak detector samples the evacuated volume between the outer O-ring and the containment O-ring. False positive results can have two causes: a large leakage in the containment seal or leakage in the inner seal. This paper describes the problem, together with possible solutions and areas that should be addressed in a Safety Analysis Report for Packaging (SARP) before a particular packaging design can be certified for transport. Ultimately, the SARP should provide justification that the requirements for leakage rate testing procedures, including the length of time needed to conduct the tests, will ensure that the containment closure seal is properly tested.

  7. Macroscopic Anatomy of the Saimaa Ringed Seal (Phoca hispida saimensis) Lower Respiratory Tract.

    PubMed

    Laakkonen, Juha; Jernvall, Jukka

    2016-04-01

    We studied the macroscopic anatomy of the lower respiratory tract of the endangered Saimaa ringed seal (Phoca hispida saimensis). Examination of one adult and one young individual found dead showed that trachea had 85 and 86 complete cartilage rings. The adjacent cartilages exhibited very few random anastomoses. There was variation in the confirmation of the trachea between the cranial and caudal part of the trachea. The right lung was divided by partly incomplete inter-lobar fissures into cranial, middle, caudal, and accessory lobes. The left lung consisted of cranial, middle, and caudal lobes. The lungs were characterized by a high amount of interlobular connective tissue. Silicone casts were prepared of the two specimens to visualize the tracheobronchial branching which was similar to that of marine ringed seals but in the Saimaa ringed seal the right middle lobar bronchus originated at the same level as the accessory lobar bronchus. Anat Rec, 299:538-543, 2016. © 2016 Wiley Periodicals, Inc. PMID:26766601

  8. Development of vacuum seals for diagnostic windows of the International Thermonuclear Experimental Reactor

    NASA Astrophysics Data System (ADS)

    Nagashima, A.; Nishitani, T.; Fujisawa, T.; Sugie, T.; Kasai, S.

    1999-01-01

    For International Thermonuclear Experiment Reactor (ITER) diagnostic windows a new sealing method based on a V-shaped elastic ring has been developed. The ring, compressed by two valves, makes vacuum tight contact on the polished edge of the window material. Two types of V-shaped rings have been tested (one of silver coated copper and one in polyimide vespel SP-1) with three different window materials (fused quartz, sapphire, and ZnSe). The wavelength range of interest is from ˜0.4 to ˜10 μm. The performance of the seals to inner pressure rise resistance, the heat cycle, and acceleration at the level expected in the ITER environment has been examined. The tests have been carried out successfully for 120 mm diameter windows.

  9. Persistent organic pollutants in Alaskan ringed seal (Phoca hispida) and walrus (Odobenus rosmarus) blubber

    USGS Publications Warehouse

    Kucklick, J.R.; Krahn, M.M.; Becker, P.R.; Porter, B.J.; Schantz, M.M.; York, G.S.; O'Hara, T. M.; Wise, S.A.

    2006-01-01

    Since 1987, the Alaska Marine Mammal Tissue Archival Project (AMMTAP) has collected tissues from 18 marine mammal species. Specimens are archived in the National Institute of Standards and Technology's National Biomonitoring Specimen Bank (NIST-NBSB). AMMTAP has collected blubber, liver and/or kidney specimens from a number of ringed seals (Phoca hispida) from the areas near Nome and Barrow, Alaska and walruses (Odobenus rosmarus) from several locations in the Bering Sea. Thirty-three ringed seal and 15 walrus blubber samples from the NIST-NBSB were analyzed for persistent organic pollutants (POPs). The compounds determined included PCBs (28 congeners or congener groups), DDT and related compounds, hexachlorobenzene (HCB), hexachlorocyclohexane isomers (HCHs), chlordanes, dieldrin, and mirex. POP concentrations in ringed seal blubber were significantly higher in Barrow than in Nome when statistically accounting for the interaction of age and gender; HCB, however, was not statistically different between the two locations. Unlike males, POP concentrations and age were not significantly correlated in females probably as a result of lactational loss. POP concentrations in walrus blubber were lower than in ringed seal blubber for ??PCBs, chlordanes, and HCHs, but higher for dieldrin and mirex. POP concentrations in ringed seals and walrus from Alaska provide further evidence that the western Arctic tends to have lower or similar POP concentrations compared to the eastern Canadian Arctic. ?? The Royal Society of Chemistry 2006.

  10. Persistent organic pollutants in Alaskan ringed seal (Phoca hispida) and walrus (Odobenus rosmarus) blubber

    USGS Publications Warehouse

    Kucklick, John R.; Krahn, Margaret M.; Becker, Paul R.; Porter, Barbara J.; Schantz, Michele M.; York, Geoffrey S.; O'Hara, Todd M.; Wise, Stephen A.

    2006-01-01

    Since 1987, the Alaska Marine Mammal Tissue Archival Project (AMMTAP) has collected tissues from 18 marine mammal species. Specimens are archived in the National Institute of Standards and Technology's National Biomonitoring Specimen Bank (NIST-NBSB). AMMTAP has collected blubber, liver and/or kidney specimens from a number of ringed seals (Phoca hispida) from the areas near Nome and Barrow, Alaska and walruses (Odobenus rosmarus) from several locations in the Bering Sea. Thirty-three ringed seal and 15 walrus blubber samples from the NIST-NBSB were analyzed for persistent organic pollutants (POPs). The compounds determined included PCBs (28 congeners or congener groups), DDT and related compounds, hexachlorobenzene (HCB), hexachlorocyclohexane isomers (HCHs), chlordanes, dieldrin, and mirex. POP concentrations in ringed seal blubber were significantly higher in Barrow than in Nome when statistically accounting for the interaction of age and gender; HCB, however, was not statistically different between the two locations. Unlike males, POP concentrations and age were not significantly correlated in females probably as a result of lactational loss. POP concentrations in walrus blubber were lower than in ringed seal blubber for ΣPCBs, chlordanes, and HCHs, but higher for dieldrin and mirex. POP concentrations in ringed seals and walrus from Alaska provide further evidence that the western Arctic tends to have lower or similar POP concentrations compared to the eastern Canadian Arctic.

  11. Regulatory concerns for leakage testing of packagings with three O-ring closure seals

    SciTech Connect

    Oras, J.J.; Towell, R.H.; Wangler, M.E.

    1997-09-01

    The American National Standard for Radioactive Materials--Leakage Tests on Packages for Shipment (ANSI N14.5) provides guidance for leakage rate testing to show that a particular packaging complies with regulatory requirements and also provides guidance in determining appropriate acceptance criteria. Recent radioactive packagings designs have incorporated three O-ring closure seals, the middle O-ring being the containment seal. These designs have the potential for false positive results of leakage rate tests. The volume between the containment O-ring and the inner O-ring is used for the helium gas required for the leakage rate tests to reduce both the amount of helium used and the time required to conduct the tests. A leak detector samples the evacuated volume between the outer O-ring and the containment O-ring. False positive results can be caused in two ways, a large leakage in the containment seal or leakage in the inner seal. This paper will describe the problem together with possible solutions/areas that need to be addressed in a Safety Analysis Report for Packagings before a particular packaging design can be certified for transport.

  12. 40 CFR Table 26 to Subpart G of... - Seal Related Factors for Internal Floating Roof Vessels

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 10 2012-07-01 2012-07-01 false Seal Related Factors for Internal..., and Wastewater Pt. 63, Subpt. G, Table 26 Table 26 to Subpart G of Part 63—Seal Related Factors for Internal Floating Roof Vessels Seal type KS n Liquid mounted resilient seal: Primary seal only 3.0 0...

  13. 40 CFR Table 26 to Subpart G of... - Seal Related Factors for Internal Floating Roof Vessels

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 10 2014-07-01 2014-07-01 false Seal Related Factors for Internal..., and Wastewater Pt. 63, Subpt. G, Table 26 Table 26 to Subpart G of Part 63—Seal Related Factors for Internal Floating Roof Vessels Seal type KS n Liquid mounted resilient seal: Primary seal only 3.0 0...

  14. 40 CFR Table 26 to Subpart G of... - Seal Related Factors for Internal Floating Roof Vessels

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 10 2013-07-01 2013-07-01 false Seal Related Factors for Internal..., and Wastewater Pt. 63, Subpt. G, Table 26 Table 26 to Subpart G of Part 63—Seal Related Factors for Internal Floating Roof Vessels Seal type KS n Liquid mounted resilient seal: Primary seal only 3.0 0...

  15. 40 CFR Table 26 to Subpart G of... - Seal Related Factors for Internal Floating Roof Vessels

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 9 2011-07-01 2011-07-01 false Seal Related Factors for Internal..., and Wastewater Pt. 63, Subpt. G, Table 26 Table 26 to Subpart G of Part 63—Seal Related Factors for Internal Floating Roof Vessels Seal type KS n Liquid mounted resilient seal: Primary seal only 3.0 0...

  16. 40 CFR Table 26 to Subpart G of... - Seal Related Factors for Internal Floating Roof Vessels

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 9 2010-07-01 2010-07-01 false Seal Related Factors for Internal..., and Wastewater Pt. 63, Subpt. G, Table 26 Table 26 to Subpart G of Part 63—Seal Related Factors for Internal Floating Roof Vessels Seal type KS n Liquid mounted resilient seal: Primary seal only 3.0 0...

  17. Aging of Weapon Seals – An Update on Butyl O-ring Issues

    SciTech Connect

    Wilson, Mark H.

    2011-07-13

    During testing under the Enhanced Surveillance Campaign in 2001, preliminary data detected a previously unknown and potentially serious concern with recently procured butyl o-rings on several programs. All butyl o-rings molded from a proprietary formulation throughout the period circa 1999 through 2001 had less than a full cure. Engineering judgment was that under curing is detrimental and could possibly lead to sub-optimum performance or, in the worst case, premature seal failure. An aging study was undertaken to ensure that suspect o-rings installed in the stockpile will retain sufficient sealing force for a minimum ten-year service life. A new prediction model developed for this study indicates suspect o-rings do not need to be replaced before the ten-year service life. Long-term testing results are reported on a yearly basis to validate the prediction model. This report documents the aging results for the period September 2002 to January 2011.

  18. Vibration and destabilizing effects of floating ring seals in compressors

    NASA Technical Reports Server (NTRS)

    Emerick, M. F.

    1982-01-01

    Operating experience on a compressor commissioned 12 years ago has presented an interesting history of sporadic increases in shaft vibration. Initial operation was satisfactory with low levels of vibration. However, after some time the shaft vibration level increased to several mils. Initially this was believed to be due to rotor unbalance from deposits formed in the passages due to process upsets. After cleaning up the rotor, operation was again increased. It was then found that the rotor vibration was primarily subsynchronous. Further investigation revealed that the original seal design was subject to wear and was no longer properly pressure balanced. A modified seal design was installed and it has operated successfully for the past six years.

  19. Assessment of two neglected effects in the analysis of an oil pumping ring seal

    NASA Technical Reports Server (NTRS)

    Keith, T. G.; Smith, P. J.

    1983-01-01

    Many factors have been found to affect the performance of a pumping ring seal. In this paper, two effects (elevated reservoir temperature and rod deformation), both heretofore neglected, are assessed through the use of a thermoelastohydrodynamic numerical model of the pumping ring. Elevated reservoir temperatures are found to result in an increase in the amount of lubricant pumped while deformation of the translating rod is shown to cause a reduction in the lubricant pumped.

  20. 77 FR 20773 - Endangered and Threatened Species; Proposed Threatened Status for Subspecies of the Ringed Seal

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-06

    ...) subspecies of ringed seals as threatened (75 FR 77476). On December 13, 2011, in consideration of substantial... deadline for the final listing determination to June 10, 2012 (FR 77466). At that time, we also announced... the initial comment period on the December 10, 2011 (75 FR 77476), proposed rule should not...

  1. O-ring tube fittings form leakproof seal in hydraulic systems

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Leakproof fittings for hydraulic systems are designed to be welded to the ends of the tubing to be joined and mated to form a seal with one o-ring at the joint. Since the fittings are coupled at only one joint, they tend to be more reliable than standard fittings coupled at two joints.

  2. Performance Evaluation of O-Ring Seals in Model 9975 Packaging Assemblies (U)

    SciTech Connect

    Skidmore, Eric

    1998-12-28

    The Materials Consultation Group of SRTC has completed a review of existing literature and data regarding the useable service life of Viton{reg_sign} GLT fluoroelastomer O-rings currently used in the Model 9975 packaging assemblies. Although the shipping and transportation period is normally limited to 2 years, it is anticipated that these packages will be used for longer-term storage of Pu-bearing materials in KAMS (K-Area Materials Storage) prior to processing or disposition in the APSF (Actinide Packaging and Storage Facility). Based on the service conditions and review of available literature, Materials Consultation concludes that there is sufficient existing data to establish the technical basis for storage of Pu-bearing materials using Parker Seals O-ring compound V835-75 (or equivalent) for up to 10 years following the 2-year shipping period. Although significant physical deterioration of the O-rings and release of product is not expected, definite changes in physical properties will occur. However, due to the complex relationship between elastomer formulation, seal properties, and competing degradation mechanisms, the actual degree of property variation and impact upon seal performance is difficult to predict. Therefore, accelerated aging and/or surveillance programs are recommended to validate the assumptions outlined in this report and to assess the long-term performance of O-ring seals under actual service conditions. Such programs could provide a unique opportunity to develop nonexistent long-term performance data, as well as address storage extension issues if necessary.

  3. [Ecology of the ringed seal (Pusa hispida) from the Bering Strait in the late Holocene].

    PubMed

    Gorlova, E N; Krylovich, O A; Savinetskiĭ, A B; Khasanov, B F

    2012-01-01

    The combined use of analysis of stable isotopes and archeozoological methods with respect to bony material from an ancient Eskimo settlement (dated 2370-810 years ago) made it possible to reveal the main distinguishing features of ringed seal in the past. On the basis of the data obtained, we suppose that in the late Holocene in the water area of the Bering Strait, there were seals of two different ecotopes: those reproducing on fast ice and those on pack ice differing not only in habitats, but also in the proportion of different food items in the diet. The ringed seals caught by ancient Eskimos during their life had a mixed diet consisting of crustaceans and fish, but in most individuals, a shift towards fish eating was observed. No significant changes in the feeding related to spawning were recorded. The dependence of feeding on body size was shown: bigger, mature individuals occupied higher trophic positions. PMID:23136743

  4. Local contamination, and not feeding preferences, explains elevated PCB concentrations in Labrador ringed seals (Pusa hispida).

    PubMed

    Brown, Tanya M; Iverson, Sara J; Fisk, Aaron T; Macdonald, Robie W; Helbing, Caren C; Reimer, Ken J

    2015-05-15

    Polychlorinated biphenyls (PCBs) in high trophic level species typically reflect the contributions of myriad sources, such that source apportionment is rarely possible. The release of PCBs by a military radar station into Saglek Bay, Labrador contaminated the local marine food web. For instance, while heavier (higher chlorinated) PCB profiles in some ringed seals (Pusa hispida) were previously attributed to this local source, differences in feeding preferences among seals could not be ruled out as a contributing factor. Herein, similar fatty acid profiles between those seals with 'local' PCB profiles and those with 'long-range' or background profiles indicate little support for the possibility that differential feeding ecologies underlay the divergent PCB profiles. Ringed seals appeared to feed predominantly on zooplankton (Mysis oculata and Themisto libellula), followed by the dusky snailfish (Liparis gibbus), arctic cod (Boreogadus saida), and shorthorn sculpin (Myoxocephalus scorpius). Principal components analysis (PCA) and PCB homolog profiles illustrated the extent of contamination of the Saglek food web, which had very different (and much heavier) PCB profiles than those food web members contaminated by 'long-range' sources. Locally contaminated prey had PCB levels that were higher (2- to 544-fold) than prey contaminated by 'long-range' sources and exceeded wildlife consumption guidelines for PCBs. The application of multivariate analyses to two distinct datasets, including PCB congeners (n=50) and fatty acids (n=65), afforded the opportunity to clearly distinguish the contribution of locally-released PCBs to a ringed seal food web from those delivered via long-ranged transport. Results from the present study strongly suggest that habitat use rather than differences in prey selection is the primary mechanism explaining the divergent PCB patterns in Labrador ringed seals. PMID:25725460

  5. Persistent organochlorine pollutants in ringed seals and polar bears collected from northern Alaska

    USGS Publications Warehouse

    Kucklick, J.R.; Struntz, W.D.J.; Becker, P.R.; York, G.W.; O'Hara, T. M.; Bohonowych, J.E.

    2002-01-01

    Blubber samples from ringed seal (Phoca hispida; n=8) and polar bear subcutaneous fat (Ursus maritimus; n=5) were collected near Barrow, Alaska in 1996 as part of the Alaska Marine Mammal Tissue Archival Project (AMMTAP) and retained in the National Biomonitoring Specimen Bank at the National Institute of Standards and Technology in Gaithersburg, Maryland (USA). The samples were analyzed for a variety of persistent organochlorine pollutants (POPs) including polychlorinated biphenyls (PCBs), hexachlorocyclohexanes (HCHs), chlordane and metabolites, hexachlorobenzene (HCB) and DDTs and metabolites. The geometric mean, on a wet mass basis, of ??PCBs (sum of 29 congeners and congener groups) were 732??282 ng/g (1 S.D.) in seals and 3395??1442 ng/g in polar bears. The geometric mean of ??DDTs, ??HCHs (??-, ??- and ??- HCH) and HCB concentrations (wet mass basis) in seals and bears were 562??261 ng/g vs. 74.8??39 ng/g, 380??213 ng/g vs. 515 ng/g, and 17.4??10.1 ng/g vs. 183??153 ng/g, respectively. The geometric mean sum of chlordane (??chlordane, sum of cis- and trans-chlordane, cis- and trans-nonachlor, oxychlordane and heptachlor epoxide) and dieldrin concentrations in ringed seals and polar bears were 753??617 ng/g vs. 720??315 ng/g and 38.6??22.8 ng/g vs. 130??65 ng/g, respectively. Apparent bioaccumulation factors (polar bear/ringed seal POP concentrations) were lower in the animals sampled near Barrow, Alaska than in those from locations in the Canadian Arctic. This suggests that polar bears are also preying on marine mammals from lower trophic levels than the ringed seals with correspondingly lower organochlorine levels, such as bowhead whale carcasses. PCB congener patterns in the samples demonstrated the metabolism of certain PCB congeners in the polar bear relative to the ringed seal in agreement with previous studies. Regional comparisons of animals collected in Alaska and Arctic Canada are presented. Copyright ?? 2002 Elsevier Science B.V.

  6. The ringed seal's last refuge and the importance of snow cover

    NASA Astrophysics Data System (ADS)

    Kelly, B. P.; Bitz, C. M.

    2010-12-01

    Ringed seals are strongly adapted to inhabiting seasonal ice cover throughout the Arctic Ocean, marginal seas, and some freshwater lakes. Their distribution has expanded and contracted with northern hemisphere ice cover and is expected to mirror declining ice cover in coming decades. Ringed seals require snow cover to provide shelter from extreme cold and from predators, and the southern extent of their range corresponds to the latitudes to which snow cover—sufficient to form and maintain subnivean lairs—extends. The lairs are especially critical to the survival of pups born and nursed under the snow in late March through May. Snow drifts 50 cm or deeper are necessary for lair occupation, and field measurements indicate that such drifting occurs only where average snow depths (on flat ice) exceed 20 cm. When snow depths are less, ringed seal pups freeze in their lairs and are vulnerable to predation by carnivores and birds. As the climate warms, winter precipitation is expected to increase in the Arctic Ocean, potentially favoring formation and occupation of lairs. At the same time, increasingly late ice formation is expected to decrease the overall accumulation of snow, an effect exacerbated by the high fraction of annual snow fall that occurs in autumn. Early snow melts also contribute to pup mortality and are likely to increase as the climate warms. We forecast April snow depths on Arctic sea ice through the year 2100 in seven runs of CCSM3. Despite predicted increases in winter precipitation in the Arctic, the model forecasted that the accumulation of snow on sea ice will decrease by almost 50% in this century. The timing of the onset of snow melt changes little in the projections, but the shallower snow pack will melt more quickly in the warmer climate. In almost all portions of the range, average snow depths are expected to be less than 20 cm and inadequate for successful rearing of ringed seal young by the end of the century and—in many locations

  7. Nozzle seal

    DOEpatents

    Groff, Russell Dennis; Vatovec, Richard John

    1978-06-11

    In an illustrative embodiment of the invention, a nuclear reactor pressure vessel, having an internal hoop from which the heated coolant emerges from the reactor core and passes through to the reactor outlet nozzles, is provided with annular sealing members operatively disposed between the outlet nozzle and the hoop and partly within a retaining annulus formed in the hoop. The sealing members are biased against the pressure vessel and the hoop and one of the sealing members is provided with a piston type pressure ring sealing member which effectively closes the path between the inlet and outlet coolants in the region about the outlet nozzle establishing a leak-proof condition. Furthermore, the flexible responsiveness of the seal assures that the seal will not structurally couple the hoop to the pressure vessel.

  8. Ringed Seal Search for Global Optimization via a Sensitive Search Model.

    PubMed

    Saadi, Younes; Yanto, Iwan Tri Riyadi; Herawan, Tutut; Balakrishnan, Vimala; Chiroma, Haruna; Risnumawan, Anhar

    2016-01-01

    The efficiency of a metaheuristic algorithm for global optimization is based on its ability to search and find the global optimum. However, a good search often requires to be balanced between exploration and exploitation of the search space. In this paper, a new metaheuristic algorithm called Ringed Seal Search (RSS) is introduced. It is inspired by the natural behavior of the seal pup. This algorithm mimics the seal pup movement behavior and its ability to search and choose the best lair to escape predators. The scenario starts once the seal mother gives birth to a new pup in a birthing lair that is constructed for this purpose. The seal pup strategy consists of searching and selecting the best lair by performing a random walk to find a new lair. Affected by the sensitive nature of seals against external noise emitted by predators, the random walk of the seal pup takes two different search states, normal state and urgent state. In the normal state, the pup performs an intensive search between closely adjacent lairs; this movement is modeled via a Brownian walk. In an urgent state, the pup leaves the proximity area and performs an extensive search to find a new lair from sparse targets; this movement is modeled via a Levy walk. The switch between these two states is realized by the random noise emitted by predators. The algorithm keeps switching between normal and urgent states until the global optimum is reached. Tests and validations were performed using fifteen benchmark test functions to compare the performance of RSS with other baseline algorithms. The results show that RSS is more efficient than Genetic Algorithm, Particles Swarm Optimization and Cuckoo Search in terms of convergence rate to the global optimum. The RSS shows an improvement in terms of balance between exploration (extensive) and exploitation (intensive) of the search space. The RSS can efficiently mimic seal pups behavior to find best lair and provide a new algorithm to be used in global

  9. Ringed Seal Search for Global Optimization via a Sensitive Search Model

    PubMed Central

    Saadi, Younes; Yanto, Iwan Tri Riyadi; Herawan, Tutut; Balakrishnan, Vimala; Chiroma, Haruna; Risnumawan, Anhar

    2016-01-01

    The efficiency of a metaheuristic algorithm for global optimization is based on its ability to search and find the global optimum. However, a good search often requires to be balanced between exploration and exploitation of the search space. In this paper, a new metaheuristic algorithm called Ringed Seal Search (RSS) is introduced. It is inspired by the natural behavior of the seal pup. This algorithm mimics the seal pup movement behavior and its ability to search and choose the best lair to escape predators. The scenario starts once the seal mother gives birth to a new pup in a birthing lair that is constructed for this purpose. The seal pup strategy consists of searching and selecting the best lair by performing a random walk to find a new lair. Affected by the sensitive nature of seals against external noise emitted by predators, the random walk of the seal pup takes two different search states, normal state and urgent state. In the normal state, the pup performs an intensive search between closely adjacent lairs; this movement is modeled via a Brownian walk. In an urgent state, the pup leaves the proximity area and performs an extensive search to find a new lair from sparse targets; this movement is modeled via a Levy walk. The switch between these two states is realized by the random noise emitted by predators. The algorithm keeps switching between normal and urgent states until the global optimum is reached. Tests and validations were performed using fifteen benchmark test functions to compare the performance of RSS with other baseline algorithms. The results show that RSS is more efficient than Genetic Algorithm, Particles Swarm Optimization and Cuckoo Search in terms of convergence rate to the global optimum. The RSS shows an improvement in terms of balance between exploration (extensive) and exploitation (intensive) of the search space. The RSS can efficiently mimic seal pups behavior to find best lair and provide a new algorithm to be used in global

  10. SEALING MEANS FOR RELATIVELY ROTATABLE MEMBERS

    DOEpatents

    Skarstrom, C.S.

    1960-10-25

    A sealing means is offered for maintaining a seal between a pair of relatively rotatable members, panticularly between a rotating shaft and a stationary member surrounding the shaft. The sealing is accomplished by means of a flange extending outward radially on each of a plurality of sealing rings mounted on the rotating member which fit into annular grooves in the stationary member and are held in sealing relation therewith by means of spring rings. In addition, means are provided for passing a sealing gas through the seal sunfaces to prevent accumulation of lubricant and for scavenging any gas which may have leaked from the internal member into the seal area.

  11. Mercury and Selenium Balance in Endangered Saimaa Ringed Seal Depend on Age and Sex.

    PubMed

    Lyytikäinen, Merja; Pätynen, Juuso; Hyvärinen, Heikki; Sipilä, Tero; Kunnasranta, Mervi

    2015-10-01

    The endangered Saimaa ringed seal (Pusa hispida saimensis) is exposed to relatively high concentrations of mercury (Hg) in freshwaters poor in selenium (Se), a known antagonist of Hg. The impact of age and sex on the bioaccumulation of Hg and Se was studied by analyzing liver, muscle, and hair samples from seals of different age groups. Adult females were found to accumulate significantly more Hg in the liver (with ca. 60% as HgSe), and less Hg in the muscles compared to adult males, which may be explained by accelerated metabolism during gestation and lactation. In adult seals, molar Se:Hg ratios in the muscles fall below one, which is considered a threshold for the emergence of adverse effects. As a result, Saimaa ringed seals may be at risk of developing health and reproductive problems. According to mass balance calculations, the pups are exposed to considerable amounts (μg/d) of mercury during gestation, although lactation is their main exposure route. In lanugo pups, Hg concentrates in the hair, and molting serves as a main detoxification route. For other age groups, demethylation followed by the formation of HgSe is the main detoxification route, and the demethylation capability develops in pups by the time of weaning. PMID:26372071

  12. Abundance of ringed seals (Pusa hispida) in the fjords of Spitsbergen, Svalbard, during the peak molting period

    USGS Publications Warehouse

    Krafft, B.A.; Kovacs, K.M.; Andersen, M.; Aars, J.; Lydersen, C.; Ergon, T.; Haug, T.

    2006-01-01

    Ringed seal (Pusa hispida) abundance in Spitsbergen, Svalbard, was estimated during the peak molting period via aerial, digital photographic surveys. A total of 9,145 images, covering 41.7%?100% of the total fast-ice cover (1,496 km2) of 18 different fjords and bays, were inspected for the presence of ringed seals. A total of 1,708 seals were counted, and when accounting for ice areas that were not covered by images, a total of 3,254 (95% CI: 3,071?3,449) ringed seals were estimated to be hauled out during the surveys. Extensive behavioral data from radio-tagged ringed seals (collected in a companion study) from one of the highest density fjords during the molting period were used to create a model that predicts the proportion of seals hauled out on any given date, time of day, and under various meteorological conditions. Applying this model to the count data from each fjord, we estimated that a total of 7,585 (95% CI: 6,332-9,085) ringed seals were present in the surveyed area during the peak molting period. Data on interannual variability in ringed seal abundance suggested higher numbers of seals in Van Keulenfjorden in 2002 compared to 2003, while other fjords with very stable ice cover showed no statistical differences. Poor ice conditions in general in 2002 probably resulted in seals from a wide area coming to Van Keulenfjorden (a large fjord with stable ice in 2002). The total estimated number of ringed seals present in the study area at the time of the survey must be regarded as a population index, or at least a minimum estimate for the area, because it does not account for individuals leaving and arriving, which might account for a considerable number of animals. The same situation is likely the case for many other studies reporting aerial census data for ringed seals. To achieve accurate estimates of population sizes from aerial surveys, more extensive knowledge of ringed seal behavior will be required.

  13. Spatial and temporal trends in perfluoroalkyl substances (PFASs) in ringed seals (Pusa hispida) from Svalbard.

    PubMed

    Routti, Heli; Gabrielsen, Geir Wing; Herzke, Dorte; Kovacs, Kit M; Lydersen, Christian

    2016-07-01

    This study investigates concentrations of perfluoroalkyl carboxylates (PFCAs), perfluoroalkyl sulfonates (PFSAs) and perfluoroalkane sulfonamides (FASA) in plasma from ringed seals sampled in the period 1990-2010 (n = 71) in Svalbard, Norway. Perfluorooctane sulfonate was dominant among the perfluoroalkyl substances. PFCAs were dominated by perfluoroundecanoate followed by perfluorononanoate. C4C8 PFCAs and perfluorooctane sulfonamide (FOSA) were detected in ≤42% of the samples. PFSA and PFCA concentrations were higher in seals sampled from Kongsfjorden, a fjord influenced by strong inflows of Atlantic Water compared to seals from fjords dominated by Arctic Water (e.g. Billefjorden). Sex, age and body condition of the seals did not influence PFAS concentrations. Due to the confounding effect of year and sampling area, temporal trends were assessed only in seals sampled from Kongsfjorden (5 years, n = 51). PFHxS and PFOS concentrations did not show significant linear trends during the whole study period, but a decrease was observed since 2004. Concentrations of all of the detected PFCAs (C9C13 PFCAs) increased until 2004 after which they have declined or stabilized. PMID:27089420

  14. Temporal trends of hexabromocyclododecane, polybrominated diphenyl ethers and polychlorinated biphenyls in ringed seals from East greenland.

    PubMed

    Vorkamp, Katrin; Rigét, Frank F; Bossi, Rossana; Dietz, Rune

    2011-02-15

    Concentrations of hexabromocyclododecane (HBCD) were determined in a combination of archived and fresh blubber samples of juvenile ringed seals from East Greenland collected between 1986 and 2008. α-HBCD was the only diastereoisomer consistently above levels of quantification and showed a significant log-linear (exponential) increase from 2.0 to 8.7 ng/g lipid weight (median concentrations) with an annual rate of +6.1%. The concentrations were up to several orders of magnitude lower than those reported for marine mammals from industrialized areas. Previously presented time trends on polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) have been extended with new data for 2006 and 2008. ΣPBDE in juvenile seals was the only parameter with a slight upward trend, however, dependent on the low 1986 concentration. Removing this data point resulted in a downward trend, which also was found for adult seals with a time trend starting in 1994. ΣPCB decreased significantly in juvenile seals, again due to the 1986 value, while no trend was found for the adult animals. This indicates stagnating PCB concentrations at a relatively high level, in some cases possibly exceeding tolerable daily intake rates for seal blubber as traditional Arctic food items. PMID:21247098

  15. Determination of spring modulus for several types of elastomeric materials (O-rings) and establishment of an open database for seals

    SciTech Connect

    McMurtry, W.M.; Hohnstreiter, G.F.

    1995-12-31

    Seals that provide the containment system interface between the packaging body and closure must function in high and low temperature environments, under dynamic and static loading conditions, and with different types of contained media. It is one of the most critical elements in the container since the container fails to meet regulations if the seal does not function properly. A research and testing program for seal materials was initiated at Sandia in 1988 with the goal of characterizing the behavior of seal materials commonly used in packages conditions as specified in the regulations (NRC IOCFR Part 71) and American National Standards Institute (ANSI) 14.5. The performance of elastomeric seals in undeformed closures at both high and low temperatures has been investigated (Bronowski 1995). Work has begun with this program to determine the response of elastomeric seals to fast acting dynamic deformations`` in the closure. The response of elastomeric o-ring seals during closure movements due to long-term deformations has already been characterized. What has not been well characterized are short-term closure movements with durations of only a few milliseconds that result in the so called ``burp`` release. Methods for generating this type of response in a repeatable manner had not been developed and standard leak detection equipment does not have a fast enough response time to measure these transient events. One factor which affects the length of the burp is the ability of the o-ring to quickly close the gap to prevent a significant leak. The dynamic characteristics of the elastomeric o-ring material including the dynamic spring modulus and internal damping are directly related to its ability to quickly close the gap. A set of tests designed to determine the dynamic properties for various material types and durometers (hardness) of elastomers that were both lubricated and dry at ambient temperature were conducted.

  16. AGING BEHAVIOR OF VITON O-RING SEALS IN THE 9975 SHIPPING PACKAGE

    SciTech Connect

    Skidmore, E.; Daugherty, W.; Hoffman, E.; Dunn, K.; Bellamy, S.

    2012-01-13

    The Savannah River Site (SRS) is storing plutonium (Pu) materials in the K-Area Materials Storage (KAMS) facility. The Pu materials were packaged according to the DOE-STD-3013 standard and shipped to the SRS in Type B 9975 packages. The robust 9975 shipping package was not designed for long-term product storage, but it is a specified part of the storage configuration and the KAMS facility safety basis credits the 9975 design with containment. Within the 9975 package, nested stainless steel containment vessels are closed with dual O-ring seals based on Viton{reg_sign} GLT or GLT-S fluoroelastomer. The aging behavior of the O-ring compounds is being studied to provide the facility with advanced notice of nonconformance and to develop life prediction models. A combination of field surveillance, leak testing of surrogate fixtures aged at bounding service temperatures, and accelerated-aging methodologies based on compression stress-relaxation and oxygen consumption analysis is being used to evaluate seal performance. A summary of the surveillance program relative to seal aging behavior is presented.

  17. TESTING AND PERFORMANCE EVALUATION OF AN INNOVATIVE INTERNAL PIPE SEALING SYSTEM FOR WASTEWATER MAIN REHABILITATION

    EPA Science Inventory

    Many utilities are seeking emerging and innovative rehabilitation technologies to extend the service life of their infrastructure systems. This report describes the testing and performance evaluation of an internal pipe sealing system, which provides a permanent physical seal fo...

  18. Integrity testing of brush seal in shroud ring of T-700 engine

    NASA Astrophysics Data System (ADS)

    Hendricks, Robert C.; Griffin, Thomas A.; Bobula, George B.; Bill, Robert C.; Howe, Harold W.

    1992-08-01

    A split-ring brush seal was fabricated, installed between two labyrinth-honeycomb shroud seals, and tested in the fourth-stage turbine of a T-700 engine. The annealed Haynes 25 bristles rubbed directly against the nonconditioned, irregular Rene 80 turbine blade shroud surface. A total of 30 hr of cyclic and steady-state data were taken with surface speeds to 335 m/s (1100 ft/s) and shroud temperatures to 620 C (1150 F). Wear appeared to be rapid initially, with an orange flash of hot brush fragments during the first engine startup, to minimal after 10 hr of operation. The brush survived the testing but experienced some bristle pullouts and severe bristle wear; some turbine interface wear and possible material transfer was noted. Future design concerns center on tribological behavior at the interface with or without lubricants.

  19. Orbital transfer rocket engine technology program: Soft wear ring seal technology

    NASA Technical Reports Server (NTRS)

    Lariviere, Brian W.

    1992-01-01

    Liquid oxygen (LOX) compatibility tests, including autogenous ignition, promoted ignition, LOX impact tests, and friction and wear tests on different PV products were conducted for several polymer materials as verification for the implementation of soft wear ring seals in advanced rocket engine turbopumps. Thermoplastics, polyimide based materials, and polyimide-imide base materials were compared for oxygen compatibility, specific wear coefficient, wear debris production, and heat dissipation mechanisms. A thermal model was generated that simulated the frictional heating input and calculated the surface temperature and temperature distribution within the seal. The predictions were compared against measured values. Heat loads in the model were varied to better match the test data and determine the difference between the measured and the calculated coefficients of friction.

  20. More economical but equally effective internally sealed concrete

    NASA Astrophysics Data System (ADS)

    White, R. M.; Taylor, M. A.; Haxo, H. E., Jr.

    1981-12-01

    Wax beads of several lower melting, lower cost wax blends can seal concrete as effectively as the paraffin-montan wax beads currently used in internally sealed concrete bridge decks, without affecting other important properties of the concrete. Savings of 5% to 25% in raw material costs can be expected to lower the cost of wax beads by approximately 5% to 20%. Since the minimum temperature required for melting the wax beads is about 25 F (14 C) lower than for the current beads, the cost of heating a bridge deck to achieve effective sealing should be reduced by approximately 15%. Beads of two formulations: 10% montan wax, 15% firbark wax, 75% paraffin 140/142 (FMP), and 5% stearic acid, 20% hydrogenated tallow, 75% paraffin 150/152 (STP), were produced in pilot plant quantities and were evaluated on two field tests. Damage to the beads during extended mixing of the concrete was suspected to be one of the causes of low strength and poor resistance to scaling of the test slabs in the first test. Some blocking of the lower melting beads at temperatures between 100 and 110 F (38 and 43 C) occurred during production in hot weather or storage for long times in warm locations. Coating the beads with 10% cement restored them to a free-flowing condition.

  1. Evaluation of soft rubber goods. [for use as O-rings, and seals on space shuttle

    NASA Technical Reports Server (NTRS)

    Merz, P. L.

    1974-01-01

    The performance of rubber goods suitable for use as O-rings, seals, gaskets, bladders and diaphragms under conditions simulating those of the space shuttle were studied. High reliability throughout the 100 flight missions planned for the space shuttle was considered of overriding importance. Accordingly, in addition to a rank ordering of the selected candidate materials based on prolonged fluid compatibility and sealability behavior, basic rheological parameters (such as cyclic hysteresis, stress relaxation, indicated modulus, etc.) were determined to develop methods capable of predicting the cumulative effect of these multiple reuse cycles.

  2. Giardia duodenalis and Cryptosporidium spp. in the intestinal contents of ringed seals (Phoca hispida) and bearded seals (Erignathus barbatus) in Nunavik, Quebec, Canada

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The prevalence in intestinal contents of ringed and bearded seals harvested for food in the Nunavik region of northern Quebec, Canada was determned for Giardia and Cryptosporidium genotypes and species. Specimens were analysed by dual color flow cytometry, immunofluorescence microscopy, and polymer...

  3. Polychlorinated biphenyl profiles in ringed seals (Pusa Hispida) reveal historical contamination by a military radar station in Labrador, Canada.

    PubMed

    Brown, Tanya M; Fisk, Aaron T; Helbing, Caren C; Reimer, Ken J

    2014-03-01

    Significant amounts of soil contaminated with polychlorinated biphenyls (PCBs) were discovered at a military radar station in Saglek Bay, Labrador, Canada, in 1996. Subsequent work showed elevated PCB concentrations in local marine sediments, in the benthic-associated food web, and in some ringed seals (Pusa hispida). The benthic-associated food web clearly reflected local PCB contamination, but the high PCB concentrations found in some ringed seals remained unexplained. In the present study, the authors assess the extent to which this local PCB source at Saglek Bay is contributing to the contamination of ringed seals in northern Labrador. Among 63 ringed seals sampled along the northern Labrador coast, 5 (8%) had PCB levels that were higher than recorded anywhere else in the Canadian Arctic. In addition, compared with seals exhibiting a long-range signal, 45% and 60% of subadults and adult males, respectively, exhibited heavier PCB congener profiles as characterized by principal components analysis, >1.6-fold higher PCB/organochlorine pesticides ratios, and higher PCB concentration-weighted average log octanol-water partition coefficient values, consistent with a local source. Despite the spatially confined nature of contaminated sediments in Saglek Bay, the influence of this PCB source is not inconsequential; PCB concentrations in locally contaminated adult males are 2-fold higher than concentrations in those exposed only to long-range PCB sources and exceed an established threshold of 1.3 mg/kg for adverse health effects in seals. PMID:24273070

  4. Demographic histories and genetic diversities of Fennoscandian marine and landlocked ringed seal subspecies

    PubMed Central

    Nyman, Tommi; Valtonen, Mia; Aspi, Jouni; Ruokonen, Minna; Kunnasranta, Mervi; Palo, Jukka U

    2014-01-01

    Island populations are on average smaller, genetically less diverse, and at a higher risk to go extinct than mainland populations. Low genetic diversity may elevate extinction probability, but the genetic component of the risk can be affected by the mode of diversity loss, which, in turn, is connected to the demographic history of the population. Here, we examined the history of genetic erosion in three Fennoscandian ringed seal subspecies, of which one inhabits the Baltic Sea ‘mainland’ and two the ‘aquatic islands’ composed of Lake Saimaa in Finland and Lake Ladoga in Russia. Both lakes were colonized by marine seals after their formation c. 9500 years ago, but Lake Ladoga is larger and more contiguous than Lake Saimaa. All three populations suffered dramatic declines during the 20th century, but the bottleneck was particularly severe in Lake Saimaa. Data from 17 microsatellite loci and mitochondrial control-region sequences show that Saimaa ringed seals have lost most of the genetic diversity present in their Baltic ancestors, while the Ladoga population has experienced only minor reductions. Using Approximate Bayesian computing analyses, we show that the genetic uniformity of the Saimaa subspecies derives from an extended founder event and subsequent slow erosion, rather than from the recent bottleneck. This suggests that the population has persisted for nearly 10,000 years despite having low genetic variation. The relatively high diversity of the Ladoga population appears to result from a high number of initial colonizers and a high post-colonization population size, but possibly also by a shorter isolation period and/or occasional gene flow from the Baltic Sea. PMID:25535558

  5. Development of seal ring carbon-graphite materials (tasks 5, 6, and 7)

    NASA Technical Reports Server (NTRS)

    Fechter, N. J.; Petrunich, P. S.

    1972-01-01

    Carbon-graphite seal ring bodies for operation at air temperatures to 1300 F(704 C) were manufactured from three select formulations. Mechanical and thermal properties, porosities, and oxidation rates were measured. The results have shown that: (1) Major property improvements anticipated from the screening studies were not realized because of processing problems associated with the scale-up in material size and probable deterioration of a phenolic resin binder; (2) the mechanical properties of a phenolic resin-bonded, carbon-graphite material can be improved by applying high pressure during carbonization; and (3) the textile form of graphite fiber used as the minor filler component in a carbon-graphite material can beneficially affect mechanical properties.

  6. Effects of the O-ring used for sealing in high-pressure balances on measurements of pressure

    NASA Astrophysics Data System (ADS)

    Woo, S. Y.; Lee, Y. J.; Choi, I. M.; Kim, B. S.; Shin, H. H.

    2002-08-01

    An oil-operated pressure balance is standard equipment widely used in the field of pressure metrology. Most of the commonly used pressure balances are in a simple piston-cylinder configuration where the piston and the cylinder can deform freely under pressure. This simple piston-cylinder assembly has an O-ring chamber on the cylinder bottom to seal the cylinder. The effects of this O-ring seal on the effective area are not well known. This paper demonstrates by the numerical method using finite element method and the experimental method that, when performing precise measurements of pressure using a pressure balance, the cylinder will be deformed by the oil pressure exerted on the bottom of the cylinder surrounded by the O-ring, causing a non-linearity in the change of effective area, and that, when the piston-cylinder assembly is used in the body with different diameters of O-ring, the effective area, i.e. the pressure, can be significantly changed. The effects of O-ring seals on the effective area of a DH5306 oil-operated pressure balance were investigated using two piston-cylinder assemblies with nominal effective areas of 2 mm2 over the pressure range of 100-300 MPa. Three different sizes of O-ring, 4.8, 8.0 and 11.7 mm in diameter, were used. The maximum change of the effective area can reach 30 ppm at 300 MPa and 18 ppm at 100 MPa due to the change of O-ring. Therefore, for precise pressure measurement, the correct understanding of the O-ring under the cylinder is required along with checking of the size of the O-ring under the cylinder whenever calibrating the piston-cylinder assembly.

  7. Hinge Moments of Sealed-Internal-Balance Arrangements for Control Surfaces I : Theoretical Investigation

    NASA Technical Reports Server (NTRS)

    Murray, Harry E.; Erwin, Mary A.

    1945-01-01

    The results of a theoretical analysis of the hinge-moment characteristics of various sealed-internal-balance arrangements for control surfaces are presented. The analysis considered overhands sealed to various types of wing structure by flexible seals spanning gaps of various widths or sealed to the wing structure by a flexible system of linked plates. Leakage was not considered; the seal was assumed to extend the full spanwise length of the control surface. The effect of the developed width of the flexible seal and of the geometry of the structure to which the seal was anchored was investigated, as well as the effect of the gap width that is sealed. The results of the investigation indicated that the most nearly linear control-surface hinge-moment characteristics can probably be obtained from a flexible seal over a narrow gap (about 0.1 of the overhang chord), which is so installed that the motion of the seal is restricted to a region behind the point of attachment of the seal to the wing structure. Control-surface hinge moments that tend to be high at large deflections and low or overbalanced at small deflections will result if a very narrow seal is used.

  8. Tolerance by ringed seals (Phoca hispida) to impact pipe-driving and construction sounds at an oil production island.

    PubMed

    Blackwell, Susanna B; Lawson, John W; Williams, Michael T

    2004-05-01

    During June and July 2000, impact pipe-driving sounds at Northstar Island (Prudhoe Bay, Alaska) were recorded underwater and in air at distances 63-3000 m from the source. Simultaneously, reactions of nearby ringed seals (in water or on ice) were documented. Pipe-driving pulses were analyzed to determine unweighted peak and rms sound-pressure levels (SPLs) and sound-exposure levels (SELs). Underwater, mean levels for these parameters reached 157 and 151 dB re: 1 microPa and 145 dB re: 1 microPa2 x s, respectively, at 63 m. The corresponding values in air were 112 and 96 dB re: 20 microPa and 90 dB re: (20 microPa)2 x s, respectively. Underwater SPLs were <180 dB re: 1 microPa at all distances. During 55 h of observation, 23 observed seals exhibited little or no reaction to any industrial noise except approaching Bell 212 helicopters. Ringed seals swam in open water near the island throughout construction activities and as close as 46 m from the pipe-driving operation. Based on current audiometric data for seals, these sounds are expected to be audible to less than 3 km underwater and at least 0.5 km in air. Most likely the seals around Northstar Island were habituated to industrial sounds. PMID:15139648

  9. Tolerance by ringed seals (Phoca hispida) to impact pipe-driving and construction sounds at an oil production island

    NASA Astrophysics Data System (ADS)

    Blackwell, Susanna B.; Lawson, John W.; Williams, Michael T.

    2004-05-01

    During June and July 2000, impact pipe-driving sounds at Northstar Island (Prudhoe Bay, Alaska) were recorded underwater and in air at distances 63-3000 m from the source. Simultaneously, reactions of nearby ringed seals (in water or on ice) were documented. Pipe-driving pulses were analyzed to determine unweighted peak and rms sound-pressure levels (SPLs) and sound-exposure levels (SELs). Underwater, mean levels for these parameters reached 157 and 151 dB re: 1 μPa and 145 dB re: 1 μPa2.s, respectively, at 63 m. The corresponding values in air were 112 and 96 dB re: 20 μPa and 90 dB re: (20 μPa)2.s, respectively. Underwater SPLs were <180 dB re: 1 μPa at all distances. During 55 h of observation, 23 observed seals exhibited little or no reaction to any industrial noise except approaching Bell 212 helicopters. Ringed seals swam in open water near the island throughout construction activities and as close as 46 m from the pipe-driving operation. Based on current audiometric data for seals, these sounds are expected to be audible to less than 3 km underwater and at least 0.5 km in air. Most likely the seals around Northstar Island were habituated to industrial sounds.

  10. Hg Stable Isotope Time Trend in Ringed Seals Registers Decreasing Sea Ice Cover in the Alaskan Arctic.

    PubMed

    Masbou, Jérémy; Point, David; Sonke, Jeroen E; Frappart, Frédéric; Perrot, Vincent; Amouroux, David; Richard, Pierre; Becker, Paul R

    2015-08-01

    Decadal time trends of mercury (Hg) concentrations in Arctic biota suggest that anthropogenic Hg is not the single dominant factor modulating Hg exposure to Arctic wildlife. Here, we present Hg speciation (monomethyl-Hg) and stable isotopic composition (C, N, Hg) of 53 Alaskan ringed seal liver samples covering a period of 14 years (1988-2002). In vivo metabolic effects and foraging ecology explain most of the observed 1.6 ‰ variation in liver δ(202)Hg, but not Δ(199)Hg. Ringed seal habitat use and migration were the most likely factors explaining Δ(199)Hg variations. Average Δ(199)Hg in ringed seal liver samples from Barrow increased significantly from +0.38 ± 0.08‰ (±SE, n = 5) in 1988 to +0.59 ± 0.07‰ (±SE, n = 7) in 2002 (4.1 ± 1.2% per year, p < 0.001). Δ(199)Hg in marine biological tissues is thought to reflect marine Hg photochemistry before biouptake and bioaccumulation. A spatiotemporal analysis of sea ice cover that accounts for the habitat of ringed seals suggests that the observed increase in Δ(199)Hg may have been caused by the progressive summer sea ice disappearance between 1988 and 2002. While changes in seal liver Δ(199)Hg values suggests a mild sea ice control on marine MMHg breakdown, the effect is not large enough to induce measurable HgT changes in biota. This suggests that Hg trends in biota in the context of a warming Arctic are likely controlled by other processes. PMID:26132925

  11. Flow Field in a Single-Stage Model Air Turbine With Seal Rings and Pre-Swirled Purge Flow

    NASA Astrophysics Data System (ADS)

    Dunn, Dennis M.

    Modern gas turbines operate at high mainstream gas temperatures and pressures, which requires high durability materials. A method of preventing these hot gases from leaking into the turbine cavities is essential for improved reliability and cost reduction. Utilizing bleed-off air from the compressor to cool internal components has been a common solution, but at the cost of decreasing turbine performance. The present work thoroughly describes the complex flow field between the mainstream gas and a single rotor-stator disk cavity, and mechanisms of mainstream gas ingestion. A combined approach of experimental measurement and numerical simulation are performed on the flow in a single-stage model gas turbine. Mainstream gas ingestion into the cavity is further reduced by utilizing two axially overlapping seal rings, one on the rotor disk and the other on the stator wall. Secondary purge air is injected into the rotor-stator cavity pre-swirled through the stator radially inboard of the two seal rings. Flow field predictions from the simulations are compared against experimental measurements of static pressure, velocity, and tracer gas concentration acquired in a nearly identical model configuration. Operational conditions were performed with a main airflow Reynolds number of 7.86e4 and a rotor disk speed of 3000rpm. Additionally the rotational Reynolds number was 8.74 e5 with a purge air nondimensional flow rate cw=4806. The simulation models a 1/14 rotationally periodic sector of the turbine rig, consisting of four rotor blades and four stator vanes. Gambit was used to generate the three-dimensional unstructured grids ranging from 10 to 20 million cells. Effects of turbulence were modeled using the single-equation Spalart-Allmaras as well as the realizable k-epsilon models. Computations were performed using FLUENT for both a simplified steady-state and subsequent time-dependent formulation. Simulation results show larger scale structures across the entire sector angle

  12. Aging Behavior of Viton{sup R} O-Ring Seals in the 9975 Shipping Package - 12594

    SciTech Connect

    Skidmore, T. Eric; Daugherty, William L.; Hoffman, Elizabeth N.; Dunn, Kerry A.; Stephen Bellamy, J.; Shuler, James M.

    2012-07-01

    The Savannah River Site (SRS) is storing plutonium (Pu) materials in the K-Area Materials Storage (KAMS) facility. The Pu materials were packaged according to the DOE-STD-3013 standard and shipped to the SRS in Type B 9975 packages. The robust 9975 shipping package was not designed for long-term product storage, but it is a specified part of the storage configuration and the KAMS facility safety basis credits the 9975 design with containment. Within the 9975 package, nested stainless steel containment vessels are closed with dual O-ring seals based on Viton{sup R} GLT or GLT-S fluoro-elastomer. The aging behavior of the O-ring compounds is being studied to provide the facility with advanced notice of nonconformance and to develop life prediction models. A combination of field surveillance, leak testing of surrogate fixtures aged at bounding service temperatures, and accelerated-aging methodologies based on compression stress-relaxation and oxygen consumption analysis is being used to evaluate seal performance. A summary of the surveillance program relative to seal aging behavior is presented. The aging behavior of fluoro-elastomer seals based on Viton{sup R} GLT and GLT-S is being studied to develop life prediction models in support of long-term storage of plutonium materials in the 9975 shipping packages at the Savannah River Site. Field surveillance data in combination with accelerated-aging data suggest a significant lifetime for the seals. Typical storage conditions are not anticipated to challenge the leak-tightness of the seals for many years. Early life prediction models based on compression stress relaxation indicate a seal lifetime of ∼12 years at the maximum service temperature predicted (93 deg. C). Seal lifetimes at lower, more realistic conditions are likely significantly longer. Service life predictions based on CSR data are thus far conservative relative to predictions based on time to leakage failure. Surveillance data on packages examined after 6

  13. Control line sealing connection

    SciTech Connect

    Tohill, H.O.

    1984-07-10

    A sealing connection for the passage of a fluid control line through adjoining members is claimed. The connection comprises a metallic tubular sealing element provided with tapered end portions, each end having internal frusto-conical surfaces and external frusto-conical surfaces in coaxial alignment with the bore through the element. The external frusto-conical surfaceas provide metal-to-metal sealing with aligned frusto-conical seating surfaces in opposed pockets formed in aligned portions of the control line at their respective openings at the adjoining surfaces of the adjoined member. The tubular sealing element is subjected to axial compression between the frusto-conical pocket seating surfaces when the adjoined members are bolted tightly together which results in deformation of its tapered end portions to provide metal-to-metal sealing with the adjoined members which is effective to seal against both internal and external fluid pressurization of the control line and without internally obstructing or restricting the control line. Secondary sealing is provided by elastomeric O-ring seals mounted in circumferential annular grooves formed in the exterior of the tubular sealing element.

  14. Non-contacting fluid ring seal systems for railcar axle bearing systems: Quarterly progress report No. 1, June 15 to September 15, 1987

    SciTech Connect

    Not Available

    1987-01-01

    The main objectives of this DOE contract is the technical development of a practical, cost effective Fluid Ring seal system capable of: Drastically reducing locomotive drawbar traction power requirements by lowering seal friction losses prevalent in present railcar axle bearing systems; increasing reliability and safety of railroad cars by minimizing bearing lubricant leakage and minimizing bearing ''hot boxes''; and improving the productivity of the railway transportation systems by reducing rolling stock ''outages'' due to long seal life. 14 refs.

  15. Transplacental Transfer of Polychlorinated Biphenyls, Polybrominated Diphenylethers, and Organochlorine Pesticides in Ringed Seals (Pusa hispida).

    PubMed

    Brown, T M; Ross, P S; Reimer, K J

    2016-01-01

    The transplacental transfer of persistent organic pollutants in marine mammals takes place at a formative developmental period, thereby exposing the fetus to endocrine-disrupting compounds. We evaluated the transplacental transfer of polychlorinated biphenyls (PCBs), polybrominated diphenylethers (PBDEs), and organochlorine pesticides (OCPs) in five pregnant ringed seals in Northern Labrador, Canada. PCBs, PBDEs, and OCPs were transferred from the mother to the fetus with average concentrations in the fetuses ranging from 0.3 ng/g lipid weight (lw) of mirex to 94 ng/g lw of PCBs. The average percent transferred to the blubber in the fetus was very low with <0.02 % for each of the compounds studied. Based on relationships observed, transfer for full-term fetuses is estimated to range from 0.03 to 0.27 %. Log K(ow) explained the transfer of PCBs (r (2) = 0.67, p < 0.001) and OCPs (r (2) = 0.62, p < 0.001) with those PCB congeners and OCP compounds having a log K(ow) of <6.0 and 4.6, respectively, because they are preferentially transferred to the fetus. Adult females transferred a contaminant mixture to their fetuses, which correlated with estimated fetal age (p < 0.001; r (2) = 0.697), with younger fetuses showing a greater proportion of compounds with low K(ow) compared with later-term fetuses. The implications for the prenatal exposure to these developmental toxicants remains unknown because current toxicity thresholds in marine mammals have only been derived from juveniles or adults. PMID:26142122

  16. Variable friction secondary seal for face seals

    NASA Technical Reports Server (NTRS)

    Dirusso, E. (Inventor)

    1986-01-01

    Vibration and stability of a primary seal ring is controlled by a secondary seal system. An inflatable bladder which forms a portion of the secondary seal varies the damping applied to this seal ring. The amplitude of vibration of the primary seal ring is sensed with a proximity probe that is connected to a microprocessor in a control system. The bladder pressure is changed by the control system to mitigate any sensed instability or vibration.

  17. 76 FR 9733 - Endangered and Threatened Species; Proposed Threatened Status for Subspecies of the Ringed Seal

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-22

    ... seals and the proposed rule for bearded seals (75 FR 77496; December 10, 2010) during these hearings...) 713- 1401. SUPPLEMENTARY INFORMATION: Background On December 10, 2010 (75 FR 77476), we published a... extended to March 25, 2011 (76 FR 6754; February 8, 2011). Public Hearings Joint Commerce-Interior...

  18. 76 FR 14882 - Endangered and Threatened Species; Proposed Threatened Status for Subspecies of the Ringed Seal

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-18

    ... seals and the proposed rule for bearded seals (75 FR 77496; December 10, 2010) during these hearings..., 2010 (75 FR 77476), we published a proposed rule to list the Arctic, Okhotsk, Baltic, and Ladoga... actions (February 8, 2011) was extended to March 25, 2011 (76 FR 6754; February 8, 2011). ]...

  19. Dynamic Face Seal Arrangement

    NASA Technical Reports Server (NTRS)

    Dellacorte, Christopher (Inventor)

    1999-01-01

    A radial face seal arrangement is disclosed comprising a stationary seal ring that is spring loaded against a seal seat affixed to a rotating shaft. The radial face seal arrangement further comprises an arrangement that not only allows for preloading of the stationary seal ring relative to the seal seat, but also provides for dampening yielding a dynamic seating response for the radial face seal arrangement. The overall seal system, especially regarding the selection of the material for the stationary seal ring, is designed to operate over a wide temperature range from below ambient up to 900 C.

  20. Satellite telemetry informs PCB source apportionment in a mobile, high trophic level marine mammal: the ringed seal (Pusa hispida).

    PubMed

    Brown, Tanya M; Luque, Sebastian; Sjare, Becky; Fisk, Aaron T; Helbing, Caren C; Reimer, Ken J

    2014-11-18

    Marine mammals are typically poor indicators of point sources of environmental contaminants as a consequence of their often complex feeding ecologies and extensive movements, all of which mask the contributions of specific inputs. The release of polychlorinated biphenyls (PCBs) by a military radar station into Saglek Bay, Labrador (Canada) has contaminated marine sediments, bottom-feeding fish, seabirds, and some ringed seals, but attributing the PCBs in the latter highly mobile animals to this source is exceedingly difficult. In addition to the application of such tools as stable isotopes (δ(15)N and δ(13)C) and univariate and multivariate statistical exploration of contaminant patterns and ratios, we used satellite telemetry to track the movements of 13 seals in their transient use of different feeding areas. Reduced size of home range and core area (i.e., areas of concentrated use), as well as increased time in coastal inlets, were important determinants of increased PCB concentrations in seals reflecting the contribution of Saglek Bay. Seals were classified into the same feeding groups using both space use and their contaminant burdens 85% of the time, highlighting the link between feeding ecology and exposure to PCBs. While the PCB source at Saglek provided a strong local signal in a remote environment, this first use of satellite telemetry demonstrates the utility of evaluating space-use strategies to better understand contaminant exposure, and more specifically the contribution of contaminant hotspots to mobile predators. PMID:25314596

  1. PCBs have declined more than DDT-group residues in Arctic ringed seals (Phoca hispida) between 1972 and 1981

    SciTech Connect

    Addison, R.F.; Zinck, M.E.; Smith, T.G.

    1986-03-01

    Mean DDT-group concentrations in the blubber of western Arctic ringed seals (Phoca hispida) sampled in 1981 were less than 1..mu..g.g/sup -1/ wet weight. Male seals had higher concentrations than did females. PCB concentrations were about half of those in a sample of the same population taken in 1972, when allowance was made for the variation of residue concentrations with age, sex, and condition. This decline probably results from the ban on PCB manufacture and use imposed in the early 1970s. Concentrations of DDT-group residues did not show any clear decline over the same interval, and the relative proportions of p,p'-DDT and p,p'-DDE suggested that there is a continuing supply of DDT to the western Arctic. The most probable source of this is by atmospheric or water transport from the Far East, where DDT was used until at least the late 1970s.

  2. PCB related effects thresholds as derived through gene transcript profiles in locally contaminated ringed seals (Pusa hispida).

    PubMed

    Brown, Tanya M; Ross, Peter S; Reimer, Ken J; Veldhoen, Nik; Dangerfield, Neil J; Fisk, Aaron T; Helbing, Caren C

    2014-11-01

    Causal evidence linking toxic injury to polychlorinated biphenyl (PCB) exposure is typically confounded by the complexity of real-world contaminant mixtures to which aquatic wildlife are exposed. A local PCB "hotspot" on the Labrador coast provided a rare opportunity to evaluate the effects of PCBs on the health of a marine mammal as this chemical dominated their persistent organic pollutant (POP) burdens. The release of approximately 260 kg of PCBs by a military radar facility over a 30 year period (1970-2000) contaminated some local marine biota, including the ringed seal (Pusa hispida). The abundance profiles of eight health-related gene transcripts were evaluated in liver samples collected from 43 ringed seals in the affected area. The mRNA transcript levels of five gene targets, including aryl hydrocarbon receptor (Ahr), interleukin-1 β (Il1b), estrogen receptor α (Esr1), insulin like growth factor receptor 1 (Igf1), and glucocorticoid receptor α (Nr3c1) correlated with increasing levels of blubber PCBs. PCB threshold values calculated using best-fit hockey-stick regression models for these five genes averaged 1,680±206 ng/g lw, with the lowest, most conservative, being 1,370 ng/g lw for Il1b. Approximately 14% of the seals in the region exceeded this threshold. The dominance of PCBs in the seals studied enabled an assessment of the effects of this chemical on gene transcripts involved in regulating the health of a highly mobile predator, something that is rarely possible in the world of complex mixtures. PMID:25286162

  3. Psychoacoustic Studies of Spotted (Phoca largha) and Ringed (Pusa hispida) Seals.

    PubMed

    Sills, Jillian M; Southall, Brandon L; Reichmuth, Colleen

    2016-01-01

    Human development of the marine environment raises questions regarding the potential adverse effects of anthropogenic noise on marine mammals. For species that live in remote Arctic regions, recent and expanding human intrusions may pose a particular threat. Northern seals are poorly studied relative to their temperate counterparts and little is known of their acoustic ecology or behavior. Given this scarcity of relevant data, studies of hearing in Arctic seals are essential to characterize their auditory capabilities and to inform management decisions. This paper describes ongoing psychoacoustic studies that are examining aspects of hearing in two ice seal species. PMID:26611064

  4. Mechanical seal assembly

    DOEpatents

    Kotlyar, Oleg M.

    2002-01-01

    An improved mechanical seal assembly is provided for sealing rotating shafts with respect to their shaft housings, wherein the rotating shafts are subject to substantial axial vibrations. The mechanical seal assembly generally includes a rotating sealing ring fixed to the shaft, a non-rotating sealing ring adjacent to and in close contact with the rotating sealing ring for forming an annular seal about the shaft, and a mechanical diode element that applies a biasing force to the non-rotating sealing ring by means of hemispherical joint. The alignment of the mechanical diode with respect to the sealing rings is maintained by a series of linear bearings positioned axially along a desired length of the mechanical diode. Alternative embodiments include mechanical or hydraulic amplification components for amplifying axial displacement of the non-rotating sealing ring and transfering it to the mechanical diode.

  5. Mechanical seal assembly

    DOEpatents

    Kotlyar, Oleg M.

    2001-01-01

    An improved mechanical seal assembly is provided for sealing rotating shafts with respect to their shaft housings, wherein the rotating shafts are subject to substantial axial vibrations. The mechanical seal assembly generally includes a rotating sealing ring fixed to the shaft, a non-rotating sealing ring adjacent to and in close contact with the rotating sealing ring for forming an annular seal about the shaft, and a mechanical diode element that applies a biasing force to the non-rotating sealing ring by means of hemispherical joint. The alignment of the mechanical diode with respect to the sealing rings is maintained by a series of linear bearings positioned axially along a desired length of the mechanical diode. Alternative embodiments include mechanical or hydraulic amplification components for amplifying axial displacement of the non-rotating sealing ring and transferring it to the mechanical diode.

  6. A survey of actuator shaft sealing techniques for extended space missions

    NASA Technical Reports Server (NTRS)

    Hotz, G. M.

    1972-01-01

    Actuators for control and articulation aboard Mariner spacecraft have employed output shaft seals to maintain an internal gaseous atmosphere. On future missions, considerably greater expected lifetimes, temperature ranges, and radiation exposures have led to a need to determine the limitations of the present O-ring output shaft seal and to examine other candidate seals. Seals suited both to dynamic and static sealing were examined for potential use in three specific actuator applications and the following candidate seals were selected: (a) O-ring seal, (b) chevron seal, (c) bellows seal (linear actuator only), (d) magnetic fluid seal (rotary actuators only) and as a backup seal to any of the foregoing, (e) the labyrinth seal.

  7. Shaft seal assembly for high speed and high pressure applications

    NASA Technical Reports Server (NTRS)

    Hadt, W. F.; Ludwig, L. P. (Inventor)

    1979-01-01

    A seal assembly is provided for reducing the escape of fluids from between a housing and a shaft rotably mounted in the housing. The seal assembly comprises a pair of seal rings resiliently connected to each other and disposed in side-by-side relationship. In each seal ring, both the internal bore surface and the radial face which faces away from the other seal ring are provided with a plurality of equi-spaced recesses. The seal faces referred to are located adjacent a seating surface of the housing. Under normal operating conditions, the seal assembly is stationary with respect to the housing, and the recesses generate life, keep the assembly spaced from the rotating shaft and allow slip therebetween. The seal assembly can seize on the shaft, and slip will then occur between the radial faces and the housing.

  8. Combined Genetic and Telemetry Data Reveal High Rates of Gene Flow, Migration, and Long-Distance Dispersal Potential in Arctic Ringed Seals (Pusa hispida)

    PubMed Central

    Martinez-Bakker, Micaela E.; Sell, Stephanie K.; Swanson, Bradley J.; Kelly, Brendan P.; Tallmon, David A.

    2013-01-01

    Ringed seals (Pusa hispida) are broadly distributed in seasonally ice covered seas, and their survival and reproductive success is intricately linked to sea ice and snow. Climatic warming is diminishing Arctic snow and sea ice and threatens to endanger ringed seals in the foreseeable future. We investigated the population structure and connectedness within and among three subspecies: Arctic (P. hispida hispida), Baltic (P. hispida botnica), and Lake Saimaa (P. hispida saimensis) ringed seals to assess their capacity to respond to rapid environmental changes. We consider (a) the geographical scale of migration, (b) use of sea ice, and (c) the amount of gene flow between subspecies. Seasonal movements and use of sea ice were determined for 27 seals tracked via satellite telemetry. Additionally, population genetic analyses were conducted using 354 seals representative of each subspecies and 11 breeding sites. Genetic analyses included sequences from two mitochondrial regions and genotypes of 9 microsatellite loci. We found that ringed seals disperse on a pan-Arctic scale and both males and females may migrate long distances during the summer months when sea ice extent is minimal. Gene flow among Arctic breeding sites and between the Arctic and the Baltic Sea subspecies was high; these two subspecies are interconnected as are breeding sites within the Arctic subspecies. PMID:24130843

  9. Seal assembly

    NASA Astrophysics Data System (ADS)

    Salt, Jonathan G.; Korzun, Ronald W.; Abbott, David R.

    1993-01-01

    A unitary annular seal structure is provided for attachment to a turbine nozzle in a gas turbine engine. The nozzle includes an annular platform disposed about a longitudinal axis of the engine. An annular array of vanes is secured to the platform. The seal structure includes an abradable annular seal member, a seal backing member, and a seal attachment ring. The ring includes an annular, radially extending, axially acting spring member positioned to cooperate with a plurality of radially extending tabs on the backing member. In use, the seal structure is positioned within a circular opening within the turbine nozzle. The nozzle includes a radially depending appendage formed as part of the nozzle platform. The spring member abuts one side of the appendage and the tabs are positioned to abut another side of the appendage for holding the annular spring member in gas sealing engagement with the appendage to thus provide a seal against gas leakage and to restrain the seal structure axially. The spring member and tabs comprise a radially slideable joint for the seal structure. To restrict circumferential motion of the structure, slots are formed in the appendage for receiving the tabs. The seal is easily replaced by bending the tabs and sliding the seal structure axially out of the nozzle. Differential thermal expansion is accommodated by the slideable seal arrangement.

  10. Design optimization and testing of a pump wear ring labyrinth seal

    NASA Technical Reports Server (NTRS)

    Rhode, D. L.; Morrison, G. L.; Ko, S. H.

    1988-01-01

    It has been demonstrated that design optimization of labyrinth seals using the present numerical model is quite beneficial. The results shown include important, but previously unknown effects on the leakage rate, especially that of step height. Further, complete details are given of a very effective seal designed using this technique for the SSME high pressure hydrogen turbopump. Measurements using turbine flow meters revealed that the optimized configuration gives 67 percent leakage reduction over the original design. These measurements also reveal important leakage effects of the axial straining of the stator, which begins during pump start-up.

  11. Butyl rubber O-ring seals: Revision of test procedures for stockpile materials

    SciTech Connect

    Domeier, L.A.; Wagter, K.R.

    1996-12-01

    Extensive testing showed little correlation between test slab and O-ring performance. New procedures, comparable to those used with the traditional test slabs, were defined for hardness, compression set, and tensile property testing on sacrificial O-ring specimens. Changes in target performance values were made as needed and were, in one case, tightened to reflect the O-ring performance data. An additional study was carried out on O-ring and slab performance vs cure cycle and showed little sensitivity of material performance to large changes in curing time. Aging and spectra of certain materials indicated that two sets of test slabs from current vendor were accidently made from EPDM rather than butyl rubber. Random testing found no O-rings made from EPDM. As a result, and additional spectroscope test will be added to the product acceptance procedures to verify the type of rubber compound used.

  12. Prototype internal target design for storage ring experiments

    NASA Astrophysics Data System (ADS)

    Petridis, N.; Grisenti, R. E.; Litvinov, Yu A.; Stöhlker, Th

    2015-11-01

    The introduction of cryogenically cooled, few micrometer-sized nozzle geometries and an essential modification of the experimental storage ring (ESR) target station allowed for a reliable operation using low-Z gases at target area densities in the range of 1013-1014 cm-2. Therefore, a remarkably versatile target source was established, enabling operation over the whole range of desired target gases (from H2 to Xe) and area densities (˜1010 to ˜1014 cm-2). Moreover, the considerably smaller orifice diameter of the new target source enables a much more compact inlet chamber while, at the same time, maintaining the demanding vacuum requirements of a storage ring. A completely new inlet chamber design is presented here, which, besides the improvements regarding the achievable area densities, will feature a variable beam width down to 1 mm at the ion beam interaction region. This is of paramount importance with respect to the realization of high precision experiments, e.g. by reducing the inaccuracy of the observation angle causing the relativistic Doppler broadening. While being intended for the deployment at the future high energy storage ring within the SPARC collaboration, the new inlet chamber can also replace the current one at the ESR or serve as an internal target for CRYRING.

  13. Characterization of the International Linear Collider damping ring optics

    NASA Astrophysics Data System (ADS)

    Shanks, J.; Rubin, D. L.; Sagan, D.

    2014-10-01

    A method is presented for characterizing the emittance dilution and dynamic aperture for an arbitrary closed lattice that includes guide field magnet errors, multipole errors and misalignments. This method, developed and tested at the Cornell Electron Storage Ring Test Accelerator (CesrTA), has been applied to the damping ring lattice for the International Linear Collider (ILC). The effectiveness of beam based emittance tuning is limited by beam position monitor (BPM) measurement errors, number of corrector magnets and their placement, and correction algorithm. The specifications for damping ring magnet alignment, multipole errors, number of BPMs, and precision in BPM measurements are shown to be consistent with the required emittances and dynamic aperture. The methodology is then used to determine the minimum number of position monitors that is required to achieve the emittance targets, and how that minimum depends on the location of the BPMs. Similarly, the maximum tolerable multipole errors are evaluated. Finally, the robustness of each BPM configuration with respect to random failures is explored.

  14. 76 FR 77466 - Endangered and Threatened Species; Proposed Threatened Status for Subspecies of the Ringed Seal

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-13

    ... largha) under the ESA (73 FR 16617). On May 28, 2008, we received a petition from the Center for Biological Diversity to list these three species of seals as threatened or endangered under the ESA... substantial scientific or commercial information indicating that the petitioned action may be warranted (73...

  15. Development of seal ring carbon-graphite materials (tasks 8, 9, and 10)

    NASA Technical Reports Server (NTRS)

    Fechter, N. J.; Petrunich, P. S.

    1973-01-01

    A screening study was conducted to develop improved carbon-graphite materials for use in self-acting seals at air temperatures to 1300 F (704 C). Property measurements on materials prepared during this study have shown that: (1) The mechanical properties of a carbon-graphite material were significantly improved by using a fine milled artificial graphite filler material and including intensive mixing, warm molding, and pitch impregnation in the processing; and (2) the oxidation resistance of a carbon-graphite material was improved by including fine milled boron carbide as an oxidation-inhibiting additive. These techniques were employed to develop a material that has 10 times more oxidation resistance than that of a widely used commercial grade and mechanical properties that approach those of the commercial grade.

  16. Circumferential shaft seal

    NASA Technical Reports Server (NTRS)

    Ludwig, L. P. (Inventor)

    1980-01-01

    A circumferential shaft seal is described which comprises two sealing rings held to a rotating shaft by means of a surrounding elastomeric band. The rings are segmented and are of a rigid sealing material such as carbon or a polyimide and graphite fiber composite.

  17. Assessment of neurotoxic effects of mercury in beluga whales (Delphinapterus leucas), ringed seals (Pusa hispida), and polar bears (Ursus maritimus) from the Canadian Arctic.

    PubMed

    Krey, Anke; Ostertag, Sonja K; Chan, Hing Man

    2015-03-15

    Marine mammals are indicator species of the Arctic ecosystem and an integral component of the traditional Inuit diet. The potential neurotoxic effects of increased mercury (Hg) in beluga whales (Delphinapterus leucas), ringed seals (Pusa hispida), and polar bears (Ursus maritimus) are not clear. We assessed the risk of Hg-associated neurotoxicity to these species by comparing their brain Hg concentrations with threshold concentrations for toxic endpoints detected in laboratory animals and field observations: clinical symptoms (>6.75 mg/kg wet weight (ww)), neuropathological signs (>4 mg/kg ww), neurochemical changes (>0.4 mg/kg ww), and neurobehavioral changes (>0.1mg/kg ww). The total Hg (THg) concentrations in the cerebellum and frontal lobe of ringed seals and polar bears were <0.5mg/kg ww, whereas the average concentration in beluga whale brain was >3mg/kg ww. Our results suggest that brain THg levels in polar bears are below levels that induce neurobehavioral effects as reported in the literature, while THg concentrations in ringed seals are within the range that elicit neurobehavioral effects and individual ringed seals exceed the threshold for neurochemical changes. The relatively high THg concentration in beluga whales exceeds all of the neurotoxicity thresholds assessed. High brain selenium (Se):Hg molar ratios were observed in all three species, suggesting that Se could protect the animals from Hg-associated neurotoxicity. This assessment was limited by several factors that influence neurotoxic effects in animals, including: animal species; form of Hg in the brain; and interactions with modifiers of Hg-associated toxicity, such as Se. Comparing brain Hg concentrations in wildlife with concentrations of appropriate laboratory studies can be used as a tool for risk characterization of the neurotoxic effects of Hg in Arctic marine mammals. PMID:24958011

  18. Comparative hepatic in vitro depletion and metabolite formation of major perfluorooctane sulfonate precursors in Arctic polar bear, beluga whale, and ringed seal.

    PubMed

    Letcher, Robert J; Chu, Shaogang; McKinney, Melissa A; Tomy, Gregg T; Sonne, Christian; Dietz, Rune

    2014-10-01

    Perfluorooctane sulfonate (PFOS) has been reported to be among the most concentrated persistent organic pollutants in Arctic marine wildlife. The present study examined the in vitro depletion of major PFOS precursors, N-ethyl-perfluorooctane sulfonamide (N-EtFOSA) and perfluorooctane sulfonamide (FOSA), as well as metabolite formation using an assay based on enzymatically viable liver microsomes for three top Arctic marine mammalian predators, polar bear (Ursus maritimus), beluga whale (Delphinapterus leucas), and ringed seal (Pusa hispida), and in laboratory rat (Rattus rattus) serving as a general mammalian model and positive control. Rat assays showed that N-EtFOSA (38 nM or 150 ng mL(-1)) to FOSA metabolism was >90% complete after 10 min, and at a rate of 23 pmol min(-1) mg(-1) protein. Examining all species in a full 90 min incubation assay, there was >95% N-EtFOSA depletion for the rat active control and polar bear microsomes, ∼65% for ringed seals, and negligible depletion of N-EtFOSA for beluga whale. Concomitantly, the corresponding in vitro formation of FOSA from N-EtFOSA was also quantitatively rat≈polar bear>ringed seal>beluga whale. A lack of enzymatic ability and/or a rate too slow to be detected likely explains the lack of N-EtFOSA to FOSA transformation for beluga whale. In the same assays, the depletion of the FOSA metabolite was insignificant (p>0.01) and with no concomitant formation of PFOS metabolite. This suggests that, in part, a source of FOSA is the biotransformation of accumulated N-EtFOSA in free-ranging Arctic ringed seal and polar bear. PMID:25048910

  19. Fluid pressure balanced seal

    NASA Technical Reports Server (NTRS)

    Marsh, H. W. (Inventor)

    1966-01-01

    A seal which increases in effectiveness with increasing pressure is presented. The seal's functional capability throughout both static and dynamic operation makes it particularly useful for sealing ball valve ports. Other features of the seal include the ability to seal two opposed surfaces simultaneously, tolerance of small misalignments, tolerance of wide temperature ranges, ability to maintain positive sealing contact under conditions of internal or external pressurization, and ability to conform to slight irregularities in seal or surface contours.

  20. Triple acting radial seal

    DOEpatents

    Ebert, Todd A; Carella, John A

    2012-03-13

    A triple acting radial seal used as an interstage seal assembly in a gas turbine engine, where the seal assembly includes an interstage seal support extending from a stationary inner shroud of a vane ring, the interstage seal support includes a larger annular radial inward facing groove in which an outer annular floating seal assembly is secured for radial displacement, and the outer annular floating seal assembly includes a smaller annular radial inward facing groove in which an inner annular floating seal assembly is secured also for radial displacement. A compliant seal is secured to the inner annular floating seal assembly. The outer annular floating seal assembly encapsulates the inner annular floating seal assembly which is made from a very low alpha material in order to reduce thermal stress.

  1. Flexible sliding seal

    NASA Technical Reports Server (NTRS)

    Wallenhorst, E. L.

    1980-01-01

    Circular seal both slides and flexes to accomodate relative motion between two sealed members. Originally developed for Space Shuttle orbiter, it contains sliding seal to accommodate engine gimbaling and flexible seal that absorbs forward motion at high thrust of engine heat shield relative to airframe. Other possible applications are in support structures of heavy machinery and vehicle engines. Flexible sliding seal is ring about 7 feet in diameter and can withstand temperatures up to 1,600 F.

  2. Seal arrangement

    DOEpatents

    Lundholm, Gunnar

    1987-01-01

    A seal arrangement is provided for preventing gas leakage along a reciprocating piston rod or other reciprocating member passing through a wall which separates a high pressure gas chmber and a low pressure gas chamber. Liquid lubricant is applied to the lower pressure side of a sealing gland surrounding the piston rod to prevent the escape of gas between the rod and the gland. The sealing gland is radially forced against the piston rod by action of a plurality of axially stacked O-rings influenced by an axially acting spring as well as pressure from the gas.

  3. Ultra high vacuum seal arrangement

    SciTech Connect

    Flaherty, R.

    1981-08-11

    Arrangement for demountably sealing two concentric metallic tubes in an ultra high vacuum system which facilitates remote actuation is claimed. A tubular seal includes integral spaced lips which circumferentially engage the metallic tubes. The lips plastically deform the metallic tubes by mechanical forces resulting from a martensite to austenite transformation of the tubular seal upon application of a predetermined temperature. The sealing force is released upon application of another temperature which causes a transformation from the stronger austenite to the weaker martensite. Use of a dual acting sealing ring and driving ring circumferentially contacting the sealing ring is particularly applicable to sealing larger diameter concentric metallic members.

  4. Ultra high vacuum seal arrangement

    DOEpatents

    Flaherty, Robert

    1981-01-01

    Arrangement for demountably sealing two concentric metallic tubes in an ultra high vacuum system which facilitates remote actuation. A tubular seal includes integral spaced lips which circumferentially engage the metallic tubes. The lips plastically deform the metallic tubes by mechanical forces resulting from a martensite to austenite transformation of the tubular seal upon application of a predetermined temperature. The sealing force is released upon application of another temperature which causes a transformation from the stronger austenite to the weaker martensite. Use of a dual acting sealing ring and driving ring circumferentially contacting the sealing ring is particularly applicable to sealing larger diameter concentric metallic members.

  5. Salinity and water temperature observations from the inaccessible waters beneath the dense ice mélange and tidewater glacier margins in Greenland obtained using instrumented ringed seals

    NASA Astrophysics Data System (ADS)

    Mernild, Sebastian H.; Holland, David M.; Holland, Denise; Rosing-Asvid, Aqqalu

    2015-04-01

    Observations obtained by ringed seals (Pusa hispida) near tidewater glacier margins in Ilulissat Icefjord and Sermilik Fjord provide a novel platform to examine the otherwise inaccessible waters beneath the dense ice melangé within the first 0-10 km of the calving front - to advance our understanding of the hydrographic conditions of the waters near the outlet glaciers. CTD (Conductivity, Temperature, and Depth) Oceanography SRDL (Satellite Relay Data Logger) instruments were mounted on ringed seals with the aim of continuously measuring water salinity, depth, and the location (coordinates) of the seals. Instruments were mounted in August and September to illustrate the non-summer month's variability. A clear link, for example, in the north and south arms of Ilulissat Icefjord is shown after spikes in ice sheet melt water runoff on salinity changes in the upper water column. Small-amplitude runoff variability during the recession of runoff in late-summer did not create a clear signal in fjord salinity variability. The effect of runoff spikes on fjord salinity is less pronounced near the ice-margin of Jakobshavn Glacier than in the north and south arms. The vertically uneven change in salinity in days after a runoff peak indicate uneven vertical distribution of runoff draining through the glacier margin, where most runoff entered the fjord in the upper 50 m (the amount of englacial runoff decreased from the water surface and downwards). The seal-dive salinity profiles did not capture any signal of englacial freshwater entering the fjord across the grounding line. Even though, the seal observations seems to advance our understanding of hydrographic changes in the inaccessible waters beneath the dense ice mélange at the tide water margins.

  6. Nozzle seal

    DOEpatents

    Herman, Richard Frederick

    1977-10-25

    In an illustrative embodiment of the invention, a nuclear reactor pressure vessel, having an internal hoop from which the heated coolant emerges from the reactor core and passes through to the reactor outlet nozzles, is provided with sealing members operatively disposed between the outlet nozzle and the hoop. The sealing members are biased against the pressure vessel and the hoop and are connected by a leak restraining member establishing a leak-proof condition between the inlet and outlet coolants in the region about the outlet nozzle. Furthermore, the flexible responsiveness of the seal assures that the seal will not structurally couple the hoop to the pressure vessel.

  7. Influence of ceramic package internal components on the performance of vacuum sealed uncooled bolometric detectors

    NASA Astrophysics Data System (ADS)

    Paquet, Alex; Deshaies, Sébastien; Desroches, Yan; Whalin, Jeff; Topart, Patrice

    2013-03-01

    INO has developed a hermetic vacuum packaging technology for uncooled bolometric detectors based on ceramic leadless chip carriers (LCC). Cavity pressures less than 3 mTorr are obtained. Processes are performed in a state-of-the art semi-automated vacuum furnace that allows for independent activation of non-evaporable thin film getters. The getter activation temperature is limited by both the anti-reflection coated silicon or germanium window and the MEMS device built on CMOS circuits. Temperature profiles used to achieve getter activation and vacuum sealing were optimized to meet lifetime and reliability requirements of packaged devices. Internal package components were carefully selected with respect to their outgassing behavior so that a good vacuum performance was obtained. In this paper, INO's packaging process is described. The influence of various package internal components, in particular the CMOS circuits, on vacuum performance is presented. The package cavity pressure was monitored using INO's pressure microsensors and the gas composition was determined by internal vapor analysis. Lifetime was derived from accelerated testing after storage of packaged detectors at various temperatures from room temperature to 120°C. A hermeticity yield over 80% was obtained for batches of twelve devices packaged simultaneously. Packaged FPAs submitted to standard MIL-STD-810 reliability testing (vibration, shock and temperature cycling) exhibited no change in IR response. Results show that vacuum performance strongly depends on CMOS circuit chips. Detectors packaged using a thin film getter show no change in cavity pressure after storage for more than 30 days at 120°C. Moreover, INO's vacuum sealing process is such that even without a thin film getter, a base pressure of less than 10 mTorr is obtained and no pressure change is observed after 40 days at 85°C.

  8. A comparison of ringed and bearded seal diet, condition and productivity between historical (1975-1984) and recent (2003-2012) periods in the Alaskan Bering and Chukchi seas

    NASA Astrophysics Data System (ADS)

    Crawford, Justin A.; Quakenbush, Lori T.; Citta, John J.

    2015-08-01

    Reductions in summer sea ice in the Chukchi and Beaufort seas are expected to affect what has been an ice-adapted marine food web in the Pacific Arctic. To determine whether recent decreases in sea ice have affected ice-associated marine predators (i.e., ringed, Pusa hispida, and bearded seals, Erignathus barbatus) in the Bering and Chukchi seas we compared diet, body condition, growth, productivity, and the proportion of pups harvested (an index of weaning success) for seals of each species harvested by 11 Alaskan villages during two periods; a historical (1975-1984) and a recent period (2003-2012). We also examined how changes in indices of seal health may be correlated with the reduction of sea ice characteristic of the recent period. For ringed seals ⩾1 year of age, the % frequency of occurrence (%FO) of Arctic cod (Boreogadus saida), walleye pollock (Gadus chalcogramma), rainbow smelt (Osmerus mordax), and Pacific herring (Clupea pallasi) increased from the historic to the recent period, while the %FO of invertebrates decreased for both pups and seals ⩾1 year of age. For bearded seals ⩾1 year of age, the %FO of Arctic cod, pricklebacks, and flatfish increased during the recent period, while the %FO of saffron cod (Eleginus gracilis) decreased for pups. Although invertebrates did not change overall for either age class, decreases occurred in 10 of 24 specific prey categories, for bearded seals ⩾1 year of age; only echiurids increased. The %FO of gastropods and bivalves increased for pups while isopods and one species of shrimp and crab decreased in occurrence. During the recent period ringed seals grew faster, had thicker blubber, had no change in pregnancy rate, matured 2 years earlier, and a larger proportion of pups was harvested than during the historical period. Correlations with spring ice concentration showed that the growth and blubber thickness of seals ⩾1 year of age, blubber thickness of pups, and the proportion of pups in the harvest all

  9. Self-Sealing Cryogenic Fitting

    NASA Technical Reports Server (NTRS)

    Jia, Lin Xiang; Chow, Wen Lung; Moslemian, Davood; Lin, Gary; Melton, Greg

    1994-01-01

    Self-sealing fitting for cryogenic tubes remains free of leakage from room temperature to liquid-helium temperature even at internal pressure as high as 2.7 MPa. Fitting comprises parts made of materials with different coefficients of thermal expansion to prevent leakage gaps from forming as temperature decreases. Consists of coupling nut, two flared tube ends, and flared O-ring spacer. Spacer contracts more than tube ends do as temperature decreases. This greater contraction seals tube ends more tightly, preventing leakage.

  10. Rotary shaft sealing assembly

    DOEpatents

    Dietle, Lannie L.; Schroeder, John E.; Kalsi, Manmohan S.; Alvarez, Patricio D.

    2010-09-21

    A rotary shaft sealing assembly in which a first fluid is partitioned from a second fluid in a housing assembly having a rotary shaft located at least partially within. In one embodiment a lip seal is lubricated and flushed with a pressure-generating seal ring preferably having an angled diverting feature. The pressure-generating seal ring and a hydrodynamic seal may be used to define a lubricant-filled region with each of the seals having hydrodynamic inlets facing the lubricant-filled region. Another aspect of the sealing assembly is having a seal to contain pressurized lubricant while withstanding high rotary speeds. Another rotary shaft sealing assembly embodiment includes a lubricant supply providing a lubricant at an elevated pressure to a region between a lip seal and a hydrodynamic seal with a flow control regulating the flow of lubricant past the lip seal. The hydrodynamic seal may include an energizer element having a modulus of elasticity greater than the modulus of elasticity of a sealing lip of the hydrodynamic seal.

  11. Rotary shaft sealing assembly

    DOEpatents

    Dietle, Lannie L; Schroeder, John E; Kalsi, Manmohan S; Alvarez, Patricio D

    2013-08-13

    A rotary shaft sealing assembly in which a first fluid is partitioned from a second fluid in a housing assembly having a rotary shaft located at least partially within. In one embodiment a lip seal is lubricated and flushed with a pressure-generating seal ring preferably having an angled diverting feature. The pressure-generating seal ring and a hydrodynamic seal may be used to define a lubricant-filled region with each of the seals having hydrodynamic inlets facing the lubricant-filled region. Another aspect of the sealing assembly is having a seal to contain pressurized lubricant while withstanding high rotary speeds. Another rotary shaft sealing assembly embodiment includes a lubricant supply providing a lubricant at an elevated pressure to a region between a lip seal and a hydrodynamic seal with a flow control regulating the flow of lubricant past the lip seal. The hydrodynamic seal may include an energizer element having a modulus of elasticity greater than the modulus of elasticity of a sealing lip of the hydrodynamic seal.

  12. Mechanically expandable annular seal

    DOEpatents

    Gilmore, Richard F.

    1983-01-01

    A mechanically expandable annular reusable seal assembly to form an annular hermetic barrier between two stationary, parallel, and planar containment surfaces. A rotatable ring, attached to the first surface, has ring wedges resembling the saw-tooth array of a hole saw. Matching seal wedges are slidably attached to the ring wedges and have their motion restricted to be perpendicular to the second surface. Each seal wedge has a face parallel to the second surface. An annular elastomer seal has a central annular region attached to the seal wedges' parallel faces and has its inner and outer circumferences attached to the first surface. A rotation of the ring extends the elastomer seal's central region perpendicularly towards the second surface to create the fluidtight barrier. A counterrotation removes the barrier.

  13. Mechanically expandable annular seal

    DOEpatents

    Gilmore, R.F.

    1983-07-19

    A mechanically expandable annular reusable seal assembly to form an annular hermetic barrier between two stationary, parallel, and planar containment surfaces is described. A rotatable ring, attached to the first surface, has ring wedges resembling the saw-tooth array of a hole saw. Matching seal wedges are slidably attached to the ring wedges and have their motion restricted to be perpendicular to the second surface. Each seal wedge has a face parallel to the second surface. An annular elastomer seal has a central annular region attached to the seal wedges' parallel faces and has its inner and outer circumferences attached to the first surface. A rotation of the ring extends the elastomer seal's central region perpendicularly towards the second surface to create the fluid tight barrier. A counter rotation removes the barrier. 6 figs.

  14. DIRC, the internally reflecting ring imaging Cerenkov detector for BABAR: Properties of the quartz radiators

    SciTech Connect

    Schwiening, Jochen

    1998-02-01

    A description of DIRC, a particle identification detector for the BABAR experiment at the Standard Linear Collider B Factory is given. It is the barrel region of the detector and its name is an acronym for detection of internally reflected Cherenkov radiation. It is a Cherenkov ring imaging device which utilizes totally internally reflected Cherenkov light in the visible and ultraviolet regions.

  15. Rim seal for turbine wheel

    DOEpatents

    Glezer, Boris; Boyd, Gary L.; Norton, Paul F.

    1996-01-01

    A turbine wheel assembly includes a disk having a plurality of blades therearound. A ceramic ring is mounted to the housing of the turbine wheel assembly. A labyrinth rim seal mounted on the disk cooperates with the ceramic ring to seal the hot gases acting on the blades from the disk. The ceramic ring permits a tighter clearance between the labyrinth rim seal and the ceramic ring.

  16. Rings

    SciTech Connect

    Davis, R.L.

    1989-01-01

    The essence of vortex physics is that at certain low-energy scales elementary excitations of a point particle theory can behave like strings rather than particles. Vortices are the resulting string-like solutions; their thickness sets the distance scale beyond which physics is string-like rather than particle-like. String degrees of freedom are massless in the sense that excitations on a string can have an arbitrarily low frequency. Non-string degrees of freedom correspond to massive particles and are absent from the low energy spectrum. This article considers only field theories with vortices at low energies. The possible existence of a class of solitons in these vortex theories will be discussed. They are vortex rings: they are localized and finite in energy, and able to carry the quantum numbers of point particles. Rings are thus particle-like solutions of a vortex theory, which is itself a limit of a point particle field theory.

  17. Investigation into electron cloud effects in the International Linear Collider positron damping ring

    SciTech Connect

    Crittenden, J.A.; Conway, J.; Dugan, G.F.; Palmer, M.A.; Rubin, D.L.; Shanks, J.; Sonnad, K.G.; Boon, L.; Harkay, K.; Ishibashi, T.; Furman, M.A.; Guiducci, S.; Pivi, M.T.F.; Wang, L.; Crittenden, J.A.; Conway, J.; Dugan, G.F.; Palmer, M.A.; Rubin, D.L.; Shanks, J.; Sonnad, K.G.; Boon, L.; Harkay, K.; Ishibashi, T.; Furman, M.A.; Guiducci, S.; Pivi, M.T.F.; Wang, L.

    2014-02-28

    We report modeling results for electron cloud buildup and instability in the International Linear Collider positron damping ring. Updated optics, wiggler magnets, and vacuum chamber designs have recently been developed for the 5 GeV, 3.2-km racetrack layout. An analysis of the synchrotron radiation profile around the ring has been performed, including the effects of diffuse and specular photon scattering on the interior surfaces of the vacuum chamber. The results provide input to the cloud buildup simulations for the various magnetic field regions of the ring. The modeled cloud densities thus obtained are used in the instability threshold calculations. We conclude that the mitigation techniques employed in this model will suffice to allow operation of the damping ring at the design operational specifications

  18. Seals and Sealing Techniques

    NASA Technical Reports Server (NTRS)

    1972-01-01

    Developments by the aerospace industry in seals and sealing techniques are announced for possible use in other areas. The announcements presented are grouped as: sealing techniques for cryogenic fluids, high pressure applications, and modification for improved performance.

  19. International Space Station Alpha's bearing, motor, and roll ring module developmental testing and results

    NASA Technical Reports Server (NTRS)

    Obrien, David L.

    1994-01-01

    This paper presents the design and developmental testing associated with the bearing, motor, and roll ring module (BMRRM) used for the beta rotation axis on International Space Station Alpha (ISSA). The BMRRM with its controllers located in the electronic control unit (ECU), provides for the solar array pointing and tracking functions as well as power and signal transfer across a rotating interface.

  20. Tamper indicating seal

    SciTech Connect

    Romero, Juan A.; Walker, Charles A.; Blair, Dianna S.; Bodmer, Connie C.

    2012-05-29

    Seals have a flexible wire that can be looped through a hasp-like device. The seals include a body having a recess, a plug insertable into the recess and a snap ring for fastening the plug to the body. The plug and/or body can have access holes for inserting the wire into the recess. "Teeth" on the outer diameter and through-holes through the thickness of the snap ring allow for passing the ends of the flexible wire from the recess through the snap ring. The ends of the wire can be folded back over the snap ring and into engagement with the teeth. Assembly of the seal causes the ends of the wire to be securely fastened between the teeth of the snap ring and the sidewall of the recess. Seals can include a plug and/or body made of a frangible material such as glass, ceramic, glass-ceramic or brittle polymer.

  1. Analysis and design of a uniform-clearance, pumping-ring rod seal for the Stirling engine

    NASA Technical Reports Server (NTRS)

    Etsion, I.

    1980-01-01

    A uniform clearance pumping ring, as opposed to the conventional taper clearance one, is described. The uniform clearance concept eliminates complex elastohydrodynamic problems and enables a simple analytical treatment to be made. An analytical expression is derived for the pumping rate showing the effect of various design parameters on the pumping ring's performance. An optimum clearance is found by which the pumping rate is maximized and a numerical example is presented to demonstrate the potential of the uniform clearance design.

  2. PEGASYS: A proposed internal target-spectrometer facility for the PEP storage ring

    SciTech Connect

    Van Bibber, K.

    1988-09-01

    A proposal for an internal gas-jet target and forward spectrometer for the PEP storage ring is described. The beam structure, allowable luminosity (L=10/sup 33/ cm/sup /minus/2/s/sup /minus/1/ for H/sub 2/, D/sub 2/ decreasing as Z/sup /minus/1.75/ for nuclear targets) and energy (E/sub e/less than or equal to 15 GeV) make the ring ideal for multiparticle coincidence studies in the scaling regime, and where perturbative QCD may be an apt description of some exclusive and semi-inclusive reactions. 17 refs., 5 figs.

  3. Energy efficient face seal

    NASA Technical Reports Server (NTRS)

    Sehnal, J.; Sedy, J.; Etsion, I.; Zobens, A.

    1982-01-01

    Torque, face temperature, leakage, and wear of a flat face seal were compared with three coned face seals at pressures up to 2758 kPa and speeds up to 8000 rpm. Axial movement of the mating seal parts was recorded by a digital data acquisition system. The coning of the tungsten carbide primary ring ranged from .51 micro-m to 5.6 micro-m. The torque of the coned face seal balanced to 76.3% was an average 42% lower, the leakage eleven times higher, than that of the standard flat face seal. The reduction of the balance of the coned face seal to 51.3% resulted by decreasing the torque by an additional 44% and increasing leakage 12 to 230 times, depending on the seal shaft speed. No measurable wear was observed on the face of the coned seals.

  4. Seal assembly with anti-rotation pin for high pressure supercritical fluids

    DOEpatents

    Wright, Steven A.; Fuller, Robert L.

    2014-08-05

    A seal assembly for sealing a machine with a first chamber and a second chamber is provided. A rotating shaft extends through the first and second chambers, and rotates therein. The seal assembly has a seal housing, a seal ring and a seal pin. The seal housing is positionable in the machine housing. The seal housing has a seal pocket extending into a fluid side thereof, and a housing receptacle extending into an inner diameter thereof at the seal pocket. The seal ring is positionable in the seal pocket of the seal housing for forming a seal therewith. The seal ring has a ring receptacle extending into an outer diameter thereof. The ring receptacle is positionable adjacent to the housing receptacle for defining a pin hole therebetween. The seal pin is loosely positionable in the pin hole whereby movement about the seal ring is accommodated while preventing rotation thereof.

  5. Mechanical testing of a device for subcutaneous internal anterior pelvic ring fixation versus external pelvic ring fixation

    PubMed Central

    2014-01-01

    Background Although useful in the emergency treatment of pelvic ring injuries, external fixation is associated with pin tract infections, the patient’s limited mobility and a restricted surgical accessibility to the lower abdomen. In this study, the mechanical stability of a subcutaneous internal anterior fixation (SIAF) system is investigated. Methods A standard external fixation and a SIAF system were tested on pairs of Polyoxymethylene testing cylinders using a universal testing machine. Each specimen was subjected to a total of 2000 consecutive cyclic loadings at 1 Hz with sinusoidal lateral compression/distraction (+/−50 N) and torque (+/− 0.5 Nm) loading alternating every 200 cycles. Translational and rotational stiffness were determined at 100, 300, 500, 700 and 900 cycles. Results There was no significant difference in translational stiffness between the SIAF and the standard external fixation when compared at 500 (p = .089), 700 (p = .081), and 900 (p = .266) cycles. Rotational stiffness observed for the SIAF was about 50 percent higher than the standard external fixation at 300 (p = .005), 500 (p = .020), and 900 (p = .005) cycles. No loosening or failure of the rod-pin/rod-screw interfaces was seen. Conclusions In comparison with the standard external fixation system, the tested device for subcutaneous internal anterior fixation (SIAF) in vitro has similar translational and superior rotational stiffness. PMID:24684828

  6. Damped flexible seal

    DOEpatents

    DuBois, Neil J.; Amaral, Antonio M.

    1992-10-27

    A damped flexible seal assembly for a torpedo isolates the tailcone thereof rom vibrational energy present in the drive shaft assembly. A pair of outside flanges, each of which include an inwardly facing groove and an O-ring constrained therein, provide a watertight seal against the outer non-rotating surface of the drive shaft assembly. An inside flange includes an outwardly-facing groove and an O-ring constrained therein, and provides a watertight seal against the inner surface of the tail cone. Two cast-in-place elastomeric seals provide a watertight seal between the flanges and further provide a damping barrier between the outside flanges and the inside flanges for damping vibrational energy present in the drive shaft assembly before the energy can reach the tailcone through the seal assembly.

  7. An upper ocean current jet and internal waves in a Gulf Stream warm core ring

    NASA Technical Reports Server (NTRS)

    Joyce, T. M.; Stalcup, M. C.

    1984-01-01

    On June 22, 1982, the R/V Endeavor, while participating in a multi-ship study of a warm core ring 82B, encountered a strong front in the core of the ring. The vessel was headed on a radial section outward from ring center while a CTD was repeatedly raised and lowered between 10 and 300 m. Current profiles in the upper 100 m were obtained continuously with a Doppler acoustic profiling system. Above the shallow 45 m seasonal thermocline, a current jet of 4 km width was encountered having a central core of relatively light water and a maximum current of 1.1 m/s. This jet was both highly nonlinear and totally unexpected. A high frequency packet of directional internal waves was acoustically observed in the seasonal thermocline at the outer edge of the jet. Vertical velocities were large enough (6 cm/s) as to be directly observable in the Doppler returns. The waves were propagating from the northeast, parallel to the ship track, and orthogonal to the jet toward the center of the warm core ring. While a nonlinear, centrifugal term was required for the force balance of the jet, the high-frequency internal wave packet could be explained with linear, gravest-mode wave dynamics.

  8. Self-acting shaft seals

    NASA Technical Reports Server (NTRS)

    Ludwig, L. P.

    1978-01-01

    Self-acting seals are described in detail. The mathematical models for obtaining a seal force balance and the equilibrium operating film thickness are outlined. Particular attention is given to primary ring response (seal vibration) to rotating seat face runout. This response analysis reveals three different vibration models with secondary seal friction being an important parameter. Leakage flow inlet pressure drop and affects of axisymmetric sealing face deformations are discussed. Experimental data on self-acting face seals operating under simulated gas turbine conditions are given. Also a spiral groove seal design operated to 244 m/sec (800 ft/sec) is described.

  9. The modified Cobra Seal

    SciTech Connect

    Ystesund, K.J.; Drayer, D.D.

    1990-01-01

    The Cobra Seal was developed in response to the International Atomic Energy Agency's request for an in situ verifiable seal. The Type E metal cap seal, still widely used by the IAEA, must be removed and returned to Agency headquarters for verification. The Cobra Seal allows an inspector to verify seal identity and integrity on site, without removing the seal. The seal consists of a loop of multi-strand fiber optic cable, which can be routed around or through the object to be sealed, and a seal body that secures the ends of the fiber optic cable. A cutting blade in the seal body randomly cuts a portion of the optical fibers in the cable. After the seal assembly is completed, a reference image is recorded of the unique pattern of light spots produced when the seal face is illuminated. Subsequent photographs of the seal pattern are compared to the original to establish the seal identity and integrity. This paper reviews the improvements and the technology of the cobra seal system. 3 refs., 5 figs.

  10. Duct System Flammability and Air Sealing Fire Separation Assemblies in the International Residential Code

    SciTech Connect

    Rudd, A.; Prahl, D.

    2014-12-01

    IBACOS identified two barriers that limit the ability of builders to cost-effectively achieve higher energy efficiency levels in housing. These are (1) the use of duct system materials that inherently achieve airtightness and are appropriately sized for low-load houses and (2) the ability to air seal fire separation assemblies. The issues identified fall into a gray area of the codes.

  11. Duct System Flammability and Air Sealing Fire Separation Assemblies in the International Residential Code

    SciTech Connect

    Rudd, A.; Prahl, D.

    2014-12-01

    IBACOS identified two barriers that limit the ability of builders to cost-effectively achieve higher energy efficiency levels in housing. These are the use of duct system materials that inherently achieve airtightness and are appropriately sized for low-load houses and the ability to air seal fire separation assemblies. The issues identified fall into a gray area of the codes.

  12. Method of sealing a high performance automotive engine and engine assembly

    SciTech Connect

    Rosenquist, G.A.

    1994-01-04

    A method of sealing a high performance internal combustion engine with a head gasket having a fire ring comprising providing a groove in the head or block generally concentric with each said combustion opening, each groove having a land area and a generally vertical wall, and positioning the gasket on the block so that when the head is torqued down, each groove receives a fire ring and compresses the wire ring thereof to provide a primary seal therewith at the land area, the wall engages the armor of the fire ring to form a secondary seal, and the head and block clamping surfaces engage the armor to clamp the armor. The head gasket has a main body of a first thickness including a central core and facing layers laminated to the core, and defines a plurality of combustion openings. A fire ring is disposed and secured in each combustion opening, each fire ring comprising a generally U-shaped armor having a pair of legs overlying and underlying the main body adjacent a combustion opening and a central body connecting the legs and ensheathing a wire ring for providing a combustion seal. In use, the combustion seal provides a labyrinth seal against the spaced surfaces of the groove and against a corner defined by the groove. 6 figs.

  13. Microstructural Characterization and Mechanical Performance of Wafer-Level SLID Bonded Au-Sn and Cu-Sn Seal Rings for MEMS Encapsulation

    NASA Astrophysics Data System (ADS)

    Rautiainen, Antti; Xu, Hongbo; Österlund, Elmeri; Li, Jue; Vuorinen, Vesa; Paulasto-Kröckel, Mervi

    2015-11-01

    Special applications, such as microelectromechanical systems (MEMS), often require hermetic sealing in order to achieve a desired operation. Solid-liquid interdiffusion (SLID) bonding is an attractive method for encapsulating MEMS devices at the wafer-level, providing, e.g., high re-melt temperatures and tolerance for topographical variations. Several different SLID bond solutions have been investigated; however, there are only a limited number of published reliability studies available. In this paper, wafer-level Au-Sn and Cu-Sn SLID seal rings were mechanically characterized with shear and tensile tests. The evolution of bond microstructures and consequent effects on mechanical reliability were evaluated with a mixed flow gas test, a high temperature storage test and a thermal shock (TS) test. Virgin samples showed high mechanical strength. The Au-Sn system, with a thin Ni layer between the TiW adhesion layer and the bond, demonstrated a shear strength of 170 MPa. Cu-Sn, with a Cu-Cu3Sn-Cu structure, exhibited a shear strength of 275 MPa. Statistically significant decreases in strength were identified after reliability tests. The shear strength of the Au-Sn bond with an (AuSn + Au5Sn)eut structure decreased 40% in a corrosive environment. After 3000 TS cycles, the tensile strength of the Cu-Sn bond reduced by 45%. Fracture surface analysis revealed through-bond failures that were not observed previously. In cross-sectional analysis, vertical cracks were observed, which may contribute to the decrease in tensile strength.

  14. Face seal assembly for rotating drum

    DOEpatents

    Morgan, J. Giles; Rennich, Mark J.; Whatley, Marvin E.

    1982-01-01

    A seal assembly comprises a tube rotatable about its longitudinal axis and having two longitudinally spaced flanges projecting radially outwardly from the outer surface thereof. Slidably positioned against one of the flanges is a seal ring, and disposed between this seal ring and the other flange are two rings that are forced apart by springs, one of the latter rings being attached to a flexible wall.

  15. Conceptual design of International Linear Collider damping ring wiggler based on a hybrid technology.

    PubMed

    Smirnov, Alexei V

    2009-01-01

    A magnetic design of a failure-free damping ring wiggler with 100% duty factor, 55.6 mm gap, and field exceeding 1.6 T is proposed. The insertion device is based on permanent magnets and specially shimmed poles that capable to meet the requirements of the International Linear Collider (ILC) damping rings (including positron one), with field quality and gap comparable to that projected for ILC using superconducting wiggler. Performance improvement of the modified hybrid design is attained due to yoke reduction down to six separated strips and maximized packaging of the midgrade (or high-grade) parallelepiped magnet blocks surrounding the Permendur poles. Economical efficiency is demonstrated on the base of calculated amount of magnetic material. A cryogenic variant of the hybrid design may certainly provide good sustainability to harsh radiation environment and further enhancement of the design efficiency within the state of the art. PMID:19191428

  16. Conceptual design of International Linear Collider damping ring wiggler based on a hybrid technology

    NASA Astrophysics Data System (ADS)

    Smirnov, Alexei V.

    2009-01-01

    A magnetic design of a failure-free damping ring wiggler with 100% duty factor, 55.6 mm gap, and field exceeding 1.6 T is proposed. The insertion device is based on permanent magnets and specially shimmed poles that capable to meet the requirements of the International Linear Collider (ILC) damping rings (including positron one), with field quality and gap comparable to that projected for ILC using superconducting wiggler. Performance improvement of the modified hybrid design is attained due to yoke reduction down to six separated strips and maximized packaging of the midgrade (or high-grade) parallelepiped magnet blocks surrounding the Permendur poles. Economical efficiency is demonstrated on the base of calculated amount of magnetic material. A cryogenic variant of the hybrid design may certainly provide good sustainability to harsh radiation environment and further enhancement of the design efficiency within the state of the art.

  17. Conceptual design of International Linear Collider damping ring wiggler based on a hybrid technology

    SciTech Connect

    Smirnov, Alexei V.

    2009-01-15

    A magnetic design of a failure-free damping ring wiggler with 100% duty factor, 55.6 mm gap, and field exceeding 1.6 T is proposed. The insertion device is based on permanent magnets and specially shimmed poles that capable to meet the requirements of the International Linear Collider (ILC) damping rings (including positron one), with field quality and gap comparable to that projected for ILC using superconducting wiggler. Performance improvement of the modified hybrid design is attained due to yoke reduction down to six separated strips and maximized packaging of the midgrade (or high-grade) parallelepiped magnet blocks surrounding the Permendur poles. Economical efficiency is demonstrated on the base of calculated amount of magnetic material. A cryogenic variant of the hybrid design may certainly provide good sustainability to harsh radiation environment and further enhancement of the design efficiency within the state of the art.

  18. Seal designing of theodolite used in seaside environment

    NASA Astrophysics Data System (ADS)

    Jin, Humin; Yan, Xiaoxu; Hao, Wei; Zhou, Sizhong

    2014-08-01

    Based on the environment requirements in seaside there exists static and dynamic seal designing for the photoelectric Theodolite. Static seal designing emphatically includes the designing of o-ring size and mechanical property analysis of o-ring seal, which is difficult to adopt conventional dynamic seal to meet the requirements. According to practical application, the combination of the radial labyrinth seal and high quality felt seal are designed. The combination seal which better solves the seal problem of narrow radial size is a good way of dynamic seal. At the same time, there is engineering practice needing to proof the radial labyrinth seal.

  19. Some metallographic results for brush bristles and brush segments of a shroud ring brush seal tested in a T-700 engine

    NASA Technical Reports Server (NTRS)

    Hendricks, Robert C.; Griffin, Thomas A.; Bobula, George A.; Bill, Robert C.; Hull, David R.; Csavina, Kristine R.

    1994-01-01

    Post-test investigation of a T-700 engine brush seal found regions void of bristles ('yanked out'), regions of bent-over bristles near the inlet, some 'snapped' bristles near the fence, and a more uniform smeared bristle interface between the first and last axial rows of bristles. Several bristles and four brush segments were cut from the brush seal, wax mounted, polished, and analyzed. Metallographic analysis of the bristle near the rub tip showed tungsten-rich phases uniformly distributed throughout the bristle, no apparent change within 1 mu m of the interface, and possibly a small amount of titanium, which would represent a transfer from the rotor. Analysis of the bristle wear face showed nonuniform tungsten, which is indicative of material resolidification. The cut end contained oxides and internal fractures; the worn end was covered with oxide scale. Material losses due to wear and elastoplastic deformation within the shear zone and third-body lubrication effects in the contact zone are discussed.

  20. Solid rocket booster joint seal analyses

    NASA Technical Reports Server (NTRS)

    Moore, Carleton J.

    1987-01-01

    O-ring response and sealing in pressurized shell structures is examined. The study found that the key elements in the failure of the seal to be joint opening and rotation, assembly out of roundness, and O-ring seal response.

  1. Internal parity symmetry and degeneracy of Bethe Ansatz strings in the isotropic heptagonal magnetic ring

    NASA Astrophysics Data System (ADS)

    Milewski, J.; Lulek, B.; Lulek, T.; Łabuz, M.; Stagraczyński, R.

    2014-02-01

    The exact Bethe eigenfunctions for the heptagonal ring within the isotropic XXX model exhibit a doubly degenerated energy level in the three-deviation sector at the centre of the Brillouin zone. We demonstrate an explicit construction of these eigenfunctions by use of algebraic Bethe Ansatz, and point out a relation of degeneracy to parity conservation, applied to the configuration of strings for these eigenfunctions. Namely, the internal structure of the eigenfunctions (the 2-string and the 1-string, with opposite quasimomenta) admits generation of two mutually orthogonal eigenfunctions due to the fact that the strings which differ by their length are distinguishable objects.

  2. Air Force Seal Programs

    NASA Technical Reports Server (NTRS)

    Mayhew, Ellen R.

    1996-01-01

    Seal technology development is an important part of the Air Force's participation in the Integrated High Performance Turbine Engine Technology (IHPTET) initiative, the joint DOD, NASA, ARPA, and industry endeavor to double turbine engine capabilities by the turn of the century. Significant performance and efficiency improvements can be obtained through reducing internal flow system leakage, but seal environment requirements continue to become more extreme as the engine thermodynamic cycles advance towards these IHPTET goals. Seal technology continues to be pursued by the Air Force to control leakage at the required conditions. This presentation briefly describes current seal research and development programs and gives a summary of seal applications in demonstrator and developmental engines.

  3. Report of tests carried out on Viton O-ring seals to assess suitability for operation over the temperature range {minus}40 C to +220 C when used in Package Design 2863B

    SciTech Connect

    1996-12-31

    To satisfy the requirements of US Regulatory bodies the O-ring seals in the containment vessels of Package Design 2863B have to be shown to operate satisfactorily (i.e. remain leaktight) at the extremes of temperature that they are expected to experience during both normal and hypothetical accident conditions of transport. For Package Design 2863B this effectively means that the seals must remain leaktight over the temperature range {minus}40 C to + 220 C, but to ensure that an adequate safety margin exists the seals should preferably remain leaktight over the range {minus}50 C to +250 C. This test report describes the procedures and results of tests carried out on Viton seals over the temperature range {minus}50 C to +250 C. The variability of the results at low temperature, by both pressure drop and helium leakage testing, would indicate that the particular formulation of Viton tested cannot be used to provide a reliable leaktight seal at {minus}40 C. Although the results of the pressure drop tests at high temperature were satisfactory, insufficient testing has been carried out using helium leakage testing to draw a firm conclusion about the high temperature performance of the material tested.

  4. Cryogenic seal concept for static and dynamic conditions

    NASA Technical Reports Server (NTRS)

    De Gaetano, E. A.

    1968-01-01

    Seal rings reduce cryogenic pump seal leakage under static and dynamic conditions. The rings are fitted into annular diaphragms, which are affected by cryogenic pressure and temperature, to move against a mating ring, to increase seal-bearing loads under static conditions.

  5. Current-use pesticides in seawater and their bioaccumulation in polar bear-ringed seal food chains of the Canadian Arctic.

    PubMed

    Morris, Adam D; Muir, Derek C G; Solomon, Keith R; Letcher, Robert J; McKinney, Melissa A; Fisk, Aaron T; McMeans, Bailey C; Tomy, Gregg T; Teixeira, Camilla; Wang, Xiaowa; Duric, Mark

    2016-07-01

    The distribution of current-use pesticides (CUPs) in seawater and their trophodynamics were investigated in 3 Canadian Arctic marine food chains. The greatest ranges of dissolved-phase concentrations in seawater for each CUP were endosulfan sulfate (less than method detection limit (MDL) to 19 pg L(-1) ) > dacthal (0.76-15 pg L(-1) ) > chlorpyrifos (less than MDL to 8.1 pg L(-1) ) > pentachloronitrobenzene (less than MDL to 2.6 pg L(-1) ) > α-endosulfan (0.20-2.3 pg L(-1) ). Bioaccumulation factors (BAFs, water-respiring organisms) were greatest in plankton, including chlorothalonil (log BAF = 7.4 ± 7.1 L kg(-1) , mean ± standard error), chlorpyrifos (log BAF = 6.9 ± 6.7 L kg(-1) ), and α-endosulfan (log BAF = 6.5 ± 6.0 L kg(-1) ). The largest biomagnification factors (BMFs) were found for dacthal in the capelin:plankton trophic relationship (BMF = 13 ± 5.0) at Cumberland Sound (Nunvavut), and for β-endosulfan (BMF = 16 ± 4.9) and α-endosulfan (BMF = 9.3 ± 2.8) in the polar bear-ringed seal relationship at Barrow and Rae Strait (NU), respectively. Concentrations of endosulfan sulfate exhibited trophic magnification (increasing concentrations with increasing trophic level) in the poikilothermic portion of the food web (trophic magnification factor = 1.4), but all of the CUPs underwent trophic dilution in the marine mammal food web, despite some trophic level-specific biomagnification. Together, these observations are most likely indicative of metabolism of these CUPs in mammals. Environ Toxicol Chem 2016;35:1695-1707. © 2016 SETAC. PMID:27027986

  6. New infection rate of bovine mammary glands after application of an internal teat seal at dry-off.

    PubMed

    Krömker, Volker; Grabowski, Nils Th; Friedrich, Julia

    2014-02-01

    The internal teat sealant OrbeSeal® (Zoetis, Berlin, Germany) is intended to prevent new intramammary infection (IMI) throughout the dry period. The aim of this field study was to determine new infection rates in udder quarters applied exclusively with the sealant at dry-off and untreated ones (control group). For that, the new infection rate of udder quarters treated with the sealant was evaluated in a split-udder design (front right and rear left udder quarters treated, the other ones untreated) in 128 cows from nine dairy farms in North Germany that were healthy in all four udder quarters (i.e. <100 000 cells/ml, bacteriologically negative). After calving, duplicate quarter milk samples were collected twice at DIM (days in milk) 5-12 and 7 d later for culture. The new infection rates for treated and untreated groups were 3·4 and 10·5%, respectively. The results showed that applying a standardised study design with very few confounders under field conditions, using internal teat sealants reduced the new infection rate on quarter level to a third of that of the control group. Thus, internal teat sealants represent a viable option for dry-off treatment of udder-healthy cows. PMID:24351664

  7. Compliant high temperature seals for dissimilar materials

    DOEpatents

    Rynders, Steven Walton; Minford, Eric; Tressler, Richard Ernest; Taylor, Dale M.

    2001-01-01

    A high temperature, gas-tight seal is formed by utilizing one or more compliant metallic toroidal ring sealing elements, where the applied pressure serves to activate the seal, thus improving the quality of the seal. The compliant nature of the sealing element compensates for differences in thermal expansion between the materials to be sealed, and is particularly useful in sealing a metallic member and a ceramic tube art elevated temperatures. The performance of the seal may be improved by coating the sealing element with a soft or flowable coating such as silver or gold and/or by backing the sealing element with a bed of fine powder. The material of the sealing element is chosen such that the element responds to stress elastically, even at elevated temperatures, permitting the seal to operate through multiple thermal cycles.

  8. Effect of seals on rotor systems

    NASA Technical Reports Server (NTRS)

    Fleming, D. P.

    1982-01-01

    Seals can exert large forces on rotors. As an example, in turbopump ring seals film stiffness as high as 90 MN/m (500,000 lb/in) have been calculated. This stiffness is comparable to the stiffness of rotor support bearings; thus seals can play an important part in supporting and stabilizing rotor systems. The work done to determine forces generated in ring seals is reviewed. Working formulas are presented for seal stiffness and damping, and geometries to maximize stiffness are discussed. An example is described where a change in seal design stabilized a previously unstable rotor.

  9. Foil Face Seal Testing

    NASA Technical Reports Server (NTRS)

    Munson, John

    2009-01-01

    In the seal literature you can find many attempts by various researchers to adapt film riding seals to the gas turbine engine. None have been successful, potential distortion of the sealing faces is the primary reason. There is a film riding device that does accommodate distortion and is in service in aircraft applications, namely the foil bearing. More specifically a foil thrust bearing. These are not intended to be seals, and they do not accommodate large axial movement between shaft & static structure. By combining the 2 a unique type of face seal has been created. It functions like a normal face seal. The foil thrust bearing replaces the normal primary sealing surface. The compliance of the foil bearing allows the foils to track distortion of the mating seal ring. The foil seal has several perceived advantages over existing hydrodynamic designs, enumerated in the chart. Materials and design methodology needed for this application already exist. Also the load capacity requirements for the foil bearing are low since it only needs to support itself and overcome friction forces at the antirotation keys.

  10. Minimum weight design of ring and stringer stiffeners for axially compressed cylindrical shells with and without internal pressure

    NASA Technical Reports Server (NTRS)

    Block, D. L.

    1972-01-01

    Results of analytical study to determine desirable ring and stringer stiffener parameters and proportions for axially compressed stiffened isotropic cylinders with and without internal pressure are presented. This investigation examines the panel and general instability buckling modes of a stiffened cylindrical shell and from this determines desirable stiffener parameters and proportions. Classical buckling equations are used which retain the important effects of the stiffeners. The results determined by using the simpler classical buckling equations are then spot checked and verified using buckling equations which considered discrete ring stiffeners and nonlinear prebuckling deformations. For both rings and stringers, T-shaped stiffeners are preferable and the effects to stiffener shape are much more pronounced at low or zero values of the internal pressure parameter. Simple analytical expressions are developed and presented which express the stiffener area parameter, the ratio of stiffener area and elastics to shell wall area and elastic modulus, in terms of the cylinder geometry and internal pressure parameter.

  11. Photodissociation of an Internally Cold Beam of CH+ Ions in a Cryogenic Storage Ring

    NASA Astrophysics Data System (ADS)

    O'Connor, A. P.; Becker, A.; Blaum, K.; Breitenfeldt, C.; George, S.; Göck, J.; Grieser, M.; Grussie, F.; Guerin, E. A.; von Hahn, R.; Hechtfischer, U.; Herwig, P.; Karthein, J.; Krantz, C.; Kreckel, H.; Lohmann, S.; Meyer, C.; Mishra, P. M.; Novotný, O.; Repnow, R.; Saurabh, S.; Schwalm, D.; Spruck, K.; Sunil Kumar, S.; Vogel, S.; Wolf, A.

    2016-03-01

    We have studied the photodissociation of CH+ in the Cryogenic Storage Ring at ambient temperatures below 10 K. Owing to the extremely high vacuum of the cryogenic environment, we were able to store CH+ beams with a kinetic energy of ˜60 keV for several minutes. Using a pulsed laser, we observed Feshbach-type near-threshold photodissociation resonances for the rotational levels J =0 - 2 of CH+, exclusively. In comparison to updated, state-of-the-art calculations, we find excellent agreement in the relative intensities of the resonances for a given J , and we can extract time-dependent level populations. Thus, we can monitor the spontaneous relaxation of CH+ to its lowest rotational states and demonstrate the preparation of an internally cold beam of molecular ions.

  12. Photodissociation of an Internally Cold Beam of CH^{+} Ions in a Cryogenic Storage Ring.

    PubMed

    O'Connor, A P; Becker, A; Blaum, K; Breitenfeldt, C; George, S; Göck, J; Grieser, M; Grussie, F; Guerin, E A; von Hahn, R; Hechtfischer, U; Herwig, P; Karthein, J; Krantz, C; Kreckel, H; Lohmann, S; Meyer, C; Mishra, P M; Novotný, O; Repnow, R; Saurabh, S; Schwalm, D; Spruck, K; Sunil Kumar, S; Vogel, S; Wolf, A

    2016-03-18

    We have studied the photodissociation of CH^{+} in the Cryogenic Storage Ring at ambient temperatures below 10 K. Owing to the extremely high vacuum of the cryogenic environment, we were able to store CH^{+} beams with a kinetic energy of ∼60  keV for several minutes. Using a pulsed laser, we observed Feshbach-type near-threshold photodissociation resonances for the rotational levels J=0-2 of CH^{+}, exclusively. In comparison to updated, state-of-the-art calculations, we find excellent agreement in the relative intensities of the resonances for a given J, and we can extract time-dependent level populations. Thus, we can monitor the spontaneous relaxation of CH^{+} to its lowest rotational states and demonstrate the preparation of an internally cold beam of molecular ions. PMID:27035300

  13. The Ring of Fire - an internal illimination system for detector sensitivity and filter bandpass characterization

    SciTech Connect

    Scarpine, Victor E.; Kent, Stephen M.; Deustua, Susana E.; Sholl, Michael J.; Mufson, Stuart L.; Ott, Melanie N.; Wiesner, Matthew P.; Baptitst, Brian J.; /Indiana U.

    2010-07-01

    We describe a prototype of an illumination system, the Ring of Fire (ROF), which is used as part of an internal calibration system for large focal plane detector arrays in TMA (Three Mirror Anastigmat) telescope designs. Such designs have been proposed for the SNAP (SuperNova Acceleration Probe) version of a Joint Dark Energy Mission (JDEM). The ROF system illuminates the focal plane with a light beam the closely matches that of the telescope and is used for creating high spatial frequency flat fields and monitoring filter bandpasses for experiments that demand a highly accurate characterization of the detectors. We present measurements of a mockup of this prototype ROF design including studies in variations in illumination across a large focal plane.

  14. Fluid sealing

    SciTech Connect

    Nau, B.S.

    1987-01-01

    This book contains 41 papers. Some of the titles are: Evaluation of secondary containment seals for pumps on hydrocarbon duties; Valve steam sealing in nuclear plants; Design directives for liquid spattered labyrinth seals; Analysis of a novel rotary seal; Contacting mechanical seal design using a simplified hydrostatic model; and Transient thermoelastic effects in a mechanical face.

  15. Acoustic Seal

    NASA Technical Reports Server (NTRS)

    Steinetz, Bruce M. (Inventor)

    2006-01-01

    The invention relates to a sealing device having an acoustic resonator. The acoustic resonator is adapted to create acoustic waveforms to generate a sealing pressure barrier blocking fluid flow from a high pressure area to a lower pressure area. The sealing device permits noncontacting sealing operation. The sealing device may include a resonant-macrosonic-synthesis (RMS) resonator.

  16. Acoustic seal

    NASA Technical Reports Server (NTRS)

    Steinetz, Bruce M. (Inventor)

    2006-01-01

    The invention relates to a sealing device having an acoustic resonator. The acoustic resonator is adapted to create acoustic waveforms to generate a sealing pressure barrier blocking fluid flow from a high pressure area to a lower pressure area. The sealing device permits noncontacting sealing operation. The sealing device may include a resonant-macrosonic-synthesis (RMS) resonator.

  17. Laparoscopic inguinal hernia repair in children using the percutaneous internal ring suturing technique – own experience

    PubMed Central

    Patkowski, Dariusz

    2014-01-01

    Introduction Percutaneous internal ring suturing (PIRS) is a method of laparoscopic herniorrhaphy, i.e. percutaneous closure of the internal inguinal ring under the control of a telescope placed in the umbilicus. Aim To evaluate the usefulness of the PIRS technique. Material and methods Fifty-five children (39 girls and 16 boys) underwent surgery using this method in our institution between 2008 and 2010. Results In 10 cases the presence of an open inguinal canal on the opposite side was also noted during surgery, and umbilical hernia was recognized in 2 patients. In 5 cases it was necessary to convert to the open surgery because of the inability to continue the laparoscopic procedure. In 1 case, male pseudohermaphroditism was diagnosed during surgery. Recurrent inguinal hernia required a conventional method of surgery in 1 child. Other children did not exhibit the characteristics of hernia recurrence. The inguinal canals were followed up with postoperative ultrasound examination in 29 children. In 23 children, the ultrasound examination showed no dilatation of the inguinal canal. In the other 6 children dilatation of the inguinal canal or the presence of fluid within the inguinal canal was observed during ultrasound. In 6 children symptoms such as swelling and soreness around the inguinal canal developed within 3 to 6 months after surgery. Conclusions Inguinal hernia surgery using the PIRS procedure is an alternative, effective, minimally invasive method of surgery. Visualization of the peritoneal cavity allows for detection of other abnormalities, as well as for performing other procedures during the same session (such as closing the contralateral inguinal canal or umbilical hernia surgery). PMID:24729810

  18. Gland With Cantilever Seal

    NASA Technical Reports Server (NTRS)

    Melton, Patrick B.

    1989-01-01

    Single-piece gland forms tight seal on probe or tube containing liquid or gas at high pressure. Gland and probe align as assembled by simple torquing procedure. Disconnected easily and reused at same site. Made from any of wide variety of materials so compatible with application. Cantilever ring at top of gland bites into wall of tube or probe, sealing it. Wall of tube or probe must be thick enough to accommodate deformation without rupturing. Maximum deformation designed in coordination with seating and deformation of boss or conical seal.

  19. Placement Of O-Rings In Solid Rocket Booster

    NASA Technical Reports Server (NTRS)

    Wood, Charles

    1991-01-01

    Brief report proposes to modify placement of O-ring seals in joints of Solid Rocket Booster of Space Shuttle. Modified joint and seal essentially "inside-out" version of old joint and seal. O-rings placed between outer side of tang and clevis. Joint rotation pushes tang harder against O-rings, thereby making even tighter seal. Proposal derived from analysis of Space Shuttle Challenger disaster, attributed to failure of these O-ring seals.

  20. Compliant seal development

    NASA Technical Reports Server (NTRS)

    Hendricks, Robert C.

    1993-01-01

    The compliant metallic seal combines the noncontact feature of the labyrinth seal, the low leakage of a mechanical seal, and the compliant nature of the brush seal. It consists of several thin metallic elements or leaves mounted within a ring which is press fit into the housing, and in form, sort of resembles a lip seal sections wiping the shaft. A second set of overlapping cover leaves are placed on top of the shaft riding leaves which reduces leakage and provides stiffness. The leaves can be straight or angle cut. The shaft riding fingers are designed with mismatched curvature to provide lift off similar to the Rayleigh lift pads in mechanical seals with leading edge clearances nearly twice those of the trailing edge as as shown by Fleming to be optimal for gas flows in convergent seal passages. Leading edge clearances range from 300 to 500 microinches. Balance pockets beneath the leaves provide fluid film feed to the 'Rayleigh lift' surface and the proper balance ratio (mechanical seal) when combined with the static pressure and film pressure. The leaves flex in the radial direction and accommodate thermomechanical behavior as well as axial motion and angular misalignment. In the static mode, there is a net closing force on the leaves. The seals were tested to 70 psi at speeds to 16,000 rpm or surface speeds to 330 fps and temperatures from ambient to 440 F. A slow cycle through the rig critical at 10,000 rpm induced a radial vibration response of 0.004 to 0.005 inch were accommodated by the seal. Preliminary performance data are encouraging demonstrating hydrodynamic liftoff and noncontacting operation at pressure and speeds typical of gas turbine engines. The leakage performance data are significantly better than commercial labyrinth and brush seals which should be expected as this design incorporates the features of the low leakage face or mechanical seal along with the flexibility of the brush configuration.

  1. Compliant seal development

    NASA Astrophysics Data System (ADS)

    Hendricks, Robert C.

    1993-10-01

    The compliant metallic seal combines the noncontact feature of the labyrinth seal, the low leakage of a mechanical seal, and the compliant nature of the brush seal. It consists of several thin metallic elements or leaves mounted within a ring which is press fit into the housing, and in form, sort of resembles a lip seal sections wiping the shaft. A second set of overlapping cover leaves are placed on top of the shaft riding leaves which reduces leakage and provides stiffness. The leaves can be straight or angle cut. The shaft riding fingers are designed with mismatched curvature to provide lift off similar to the Rayleigh lift pads in mechanical seals with leading edge clearances nearly twice those of the trailing edge as as shown by Fleming to be optimal for gas flows in convergent seal passages. Leading edge clearances range from 300 to 500 microinches. Balance pockets beneath the leaves provide fluid film feed to the 'Rayleigh lift' surface and the proper balance ratio (mechanical seal) when combined with the static pressure and film pressure. The leaves flex in the radial direction and accommodate thermomechanical behavior as well as axial motion and angular misalignment. In the static mode, there is a net closing force on the leaves. The seals were tested to 70 psi at speeds to 16,000 rpm or surface speeds to 330 fps and temperatures from ambient to 440 F. A slow cycle through the rig critical at 10,000 rpm induced a radial vibration response of 0.004 to 0.005 inch were accommodated by the seal. Preliminary performance data are encouraging demonstrating hydrodynamic liftoff and noncontacting operation at pressure and speeds typical of gas turbine engines. The leakage performance data are significantly better than commercial labyrinth and brush seals which should be expected as this design incorporates the features of the low leakage face or mechanical seal along with the flexibility of the brush configuration.

  2. Taper-seal type metal sealing system and available applications

    NASA Astrophysics Data System (ADS)

    Kurokouchi, Satoshi; Okabe, Masayuki; Morita, Shinsaku

    2001-01-01

    A conventional disk (flat ring) gasket for ConFlat ® sealing system has been commonly applied to commercially available equipments for ultrahigh vacuum systems. However, its large redundant part which wastes the tightening force makes its handling and seal reliability problematic. We examine a taper-seal type gasket, which is newly designed to improve the inefficiency of ConFlat mechanism using conventional disk gaskets. It is remarked that the obtained seal area on a taper-seal type gasket is 1.6˜3.7 times larger than that of a conventional disk gasket. Our numencal results on stress distributions in a tightened gasket indicate that taper-seal gasket realizes highly stable seal pressure even under a lower tightening torque. High sealing reliability is thus achieved as expected which is mainly due to the wide seal area and stable seal pressure realized even for rather hard gasket material. Taper-seal type gasket also has some practical advantages. The most important of them may be that it enables to construct new edgeless metal sealing systems without a welded heavy flange. Here, edgeless sealing systems are composed of highly flexible incorporating viewports, bellows, feedthroughs, and blank-off covers, as well as any other conventional vacuum components.

  3. Earth boring bit with improved rigid face seal assembly

    SciTech Connect

    Burr, B.H.

    1987-05-19

    An earth boring bit is described with an improved pressure compensating face seal assembly having one rigid ring and sealing face carried by a bearing shaft and an opposed sealing face carried by the cutter. The bit comprises: a body; a cantilevered bearing shaft having a generally cylindrical journal bearing and positioned to extend obliquely inwardly and downwardly from the body; a cutter having a generally cylindrical bearing formed internally therein, secured for rotation about the journal bearing of the shaft; a lubrication system in the body, including a hydrostatic pressure compensator to lubricate the bearings; and a cutter seal groove formed near the outermost region of the cylindrical bearing in the cutter to have a circumferential, generally cylindrical wall.

  4. Self sealing disconnect for tubing forms metal seal after breakaway

    NASA Technical Reports Server (NTRS)

    Gernandt, H. H.

    1964-01-01

    Disconnect fittings form a positive metal seal when the fill tube pulls against a metal sleeve when disconnected by force. A specially designed sleeve surrounds the fill tube. O-rings in the shoulder of the sleeve and near the outer end of the fill tube seal against leakage.

  5. Communication through the phenyl ring: internal rotation and nuclear quadrupole splitting in p-halotoluenes

    NASA Astrophysics Data System (ADS)

    Shubert, V. Alvin; Schmitz, David; Schnell, Melanie

    2013-08-01

    The rotational spectra of three p-halotoluenes (chloro-, bromo- and iodo-) are reported in the frequency range 2-8.5 GHz, obtained with broadband Fourier-transform microwave spectroscopy. The recorded spectra are highly complicated due to low-barrier V 6 internal rotation of the methyl group as well as strong nuclear quadrupole coupling of the halogen atoms. However, these additional effects allow us, in a comparative manner, to study potential crosstalk of the two substituents via the phenyl ring. The rotational constants and other molecular parameters are reported and compared with quantum chemical calculations. The V 6 internal rotation barrier of the methyl group was found to be 145 GHz for both p-chlorotoluene species. We found that the magnitudes of the quadrupole coupling constants are increased in the halotoluenes compared to the halobenzenes. This increase is due to the +I inductive effect of the methyl group that injects additional electron density into the phenyl π-cloud, thus giving more electron density for the halogen atom to extract. This additional extraction makes the halogen-carbon bond more ionic than in the halobenzenes.

  6. Flight set 360H005 (STS-28) seals, volume 4

    NASA Technical Reports Server (NTRS)

    Curry, Jeffrey T.

    1990-01-01

    The performance is assessed of the 360H005, Fifth flight, Redesigned Solid Rocket Motors (RSMR) in respect to joint sealing issues as seen from post flight inspection of the seals and sealing surfaces. The factory joint disassembly inspections have resumed for 360H005. The new factory joint grease application is in effect and now can be assessed during the disassembly process. The RSRM is illustrated consisting of capture feature field joints as is the J-joint insulation configuration. The nozzle-to-case joint design is also illustrated, which includes 100, 7/8 inch radial bolts in conjunction with a wiper O-ring and modified insulation design. The ignition system seals and a cross section of the igniter are illustrated. The configuration of all the internal nozzle joints are also shown. The postflight inspection of both motors showed the seal components to be in excellent condition except for the indentation found on the inner primary seal of the right hand inner igniter gasket, aft face. Detailed inspection results, and inspections performed by the O-ring Inspection Team are presented.

  7. Hermetic metal seals for Stirling engines

    SciTech Connect

    White, M.A.; Emigh, S.G.; Gray, D.M.; Krogness, J.C.; Noble, J.E.; Olam, R.W.; Oster, J.F.; Riggle, P.

    1984-08-01

    Dynamic seals continue to be one of the major technical problems facing Stirling engine designers. Much effort has been expended to develop the quasi-hermetic rolling diaphragm or rollsock seal, but unpredictable lifetime has resulted in general disuse of this once promising seal. Most modern engines use some version of the Leningrader sliding seal for rod seals and a dry ring seal for piston and/or displacer seals. Reliable long-life seals remain an elusive goal. This paper documents the successful hardware implementation of metal bellows and diaphragm seals in two long-life Stirling engine applications with test data to >10/sup 10/ cycles and discusses bellows seal concepts which can provide reliable and efficient longlife seals for virtually any Stirling engine application.

  8. Liquid zone seal

    DOEpatents

    Klebanoff, Leonard E.

    2001-01-01

    A seal assembly that provides a means for establishing multiple pressure zones within a system. The seal assembly combines a plate extending from the inner wall of a housing or inner enclosure that intersects with and is immersed in the fluid contained in a well formed in a tray contained within the enclosure. The fluid is a low vapor pressure oil, chemically inert and oxidation resistant. The use of a fluid as the sealing component provides a seal that is self-healing and mechanically robust not subject to normal mechanical wear, breakage, and formation of cracks or pinholes and decouples external mechanical vibrations from internal structural members.

  9. High temperature autoclave vacuum seals

    NASA Technical Reports Server (NTRS)

    Hoffman, J. R.; Simpson, W. G.; Walker, H. M.

    1971-01-01

    Aluminum sheet forms effective sealing film at temperatures up to 728 K. Soft aluminum wire rings provide positive seal between foil and platen. For applications at temperatures above aluminum's service temperature, stainless steel is used as film material and copper wire as sealant.

  10. Air Force seal activities

    NASA Technical Reports Server (NTRS)

    Mayhew, Ellen R.

    1994-01-01

    Seal technology development is an important part of the Air Force's participation in the Integrated High Performance Turbine Engine Technology (IHPTET) initiative, the joint DOD, NASA, ARPA, and industry endeavor to double turbine engine capabilities by the turn of the century. Significant performance and efficiency improvements can be obtained through reducing internal flow system leakage, but seal environment requirements continue to become more extreme as the engine thermodynamic cycles advance towards these IHPTET goals. Brush seal technology continues to be pursued by the Air Force to reduce leakage at the required conditions. Likewise, challenges in engine mainshaft air/oil seals are also being addressed. Counter-rotating intershaft applications within the IHPTET initiative involve very high rubbing velocities. This viewgraph presentation briefly describes past and current seal research and development programs and gives a summary of seal applications in demonstrator and developmental engine testing.

  11. Oil Saving Seal

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Driven under difficult field conditions, the Army Jeep shown went more than 22,000 miles without an oil change in a test conducted by the U.S. Army Mobility Equipment Research and Development Command. Key to this exceptionally long oil life was a set of piston ring seals made of a new synthetic rubber formula called RC-34; the seal pictured, photographed after its arduous Army trial, shows no signs of deterioration. The seal and the RC-34 material, which may soon be available for use in the family auto, were developed by Ramsey Corporation, St. Louis, Missouri, a division of TRW Automotive Worldwide. The oil in an automobile engine must be I replaced every few thousand miles not because it wears out but because it becomes contaminated. The contamination sources are gasoline and combustion gases which blow by the piston rings to mix with the oil, reducing the oil's ability to lubricate properly. Seeking to prolong oil life by eliminating "blowby," Ramsey Corporation looked for a better way to seal piston rings and used NASA technology as a departure point. The parent company TRW, under contract to NASA's Jet Propulsion Laboratory, had developed seals and bladders from a type of material called elastomers which where designed to withstand the environmental extremes of interplanetary flight. That effort formed a knowledge base for research which culminated in Ramsey's RC-34 elastomer.

  12. Glass sealing

    SciTech Connect

    Brow, R.K.; Kovacic, L.; Chambers, R.S.

    1996-04-01

    Hernetic glass sealing technologies developed for weapons component applications can be utilized for the design and manufacture of fuel cells. Design and processing of of a seal are optimized through an integrated approach based on glass composition research, finite element analysis, and sealing process definition. Glass sealing procedures are selected to accommodate the limits imposed by glass composition and predicted calculations.

  13. International planetary patrol observations of Saturn's rings. II - Four color phase curves and their analysis

    NASA Technical Reports Server (NTRS)

    Esposito, L. W.; Lumme, K.; Benton, W. D.; Martin, L. J.; Ferguson, H. M.; Thompson, D. T.; Jones, S. E.

    1979-01-01

    New phase curves for Saturn's rings at an intermediate tilt angle B of about 17 deg are presented. Quantitative results for each of the A and B rings are reported in terms of the opposition effect, phase coefficient, and best logarithmic fit to the phase curve. There was no significant difference between the shape of the phase curves for the two rings in each of the four colors, and a four-parameter multiple scattering model of the rings was consistent with the observations. In this model, the difference in the phase curves for different colors can be explained by a variation in the single scattering albedo with wavelength. The observations allow the particles to have the same composition in the A and B rings, so that their different photometric behavior is explained by differences in optical depth and volume density in the two rings.

  14. Damping device for a stationary labyrinth seal

    NASA Technical Reports Server (NTRS)

    El-Aini, Yehia M. (Inventor); Mitchell, William S. (Inventor); Roberts, Lawrence P. (Inventor); Montgomery, Stuart K. (Inventor); Davis, Gary A. (Inventor)

    2010-01-01

    A stationary labyrinth seal system includes a seal housing having an annular cavity, a plurality of damping devices, and a retaining ring. The damping devices are positioned within the annular cavity and are maintained within the annular cavity by the retaining ring.

  15. Inflatable-Seal Assembly For Cryogenic Fluids

    NASA Technical Reports Server (NTRS)

    Buehler, Kurt; Fesmire, James E.

    1989-01-01

    Connector for cryogenic fluid lines quickly joined or separated, seals tightly, and reduces transfer of heat to fluid. Features redundant sealing rings inflated after joining so they wedge tightly against connector base, preventing leakage. Cylinder of FEP inflatable. Pair of threaded stainless-steel rings - one at each end of cylinder - secure cylinder in quick-disconnect assembly.

  16. International ring trial of the epidermal equivalent sensitizer potency assay: reproducibility and predictive-capacity.

    PubMed

    Teunis, Marc A T; Spiekstra, Sander W; Smits, Mieke; Adriaens, Els; Eltze, Tobias; Galbiati, Valentina; Krul, Cyrille; Landsiedel, Robert; Pieters, Raymond; Reinders, Judith; Roggen, Erwin; Corsini, Emanuela; Gibbs, Susan

    2014-01-01

    This study describes the international ring trial of the epidermal-equivalent (EE) sensitizer potency assay. This assay does not distinguish a sensitizer from a non-sensitizer, but may classify known skin sensitizers according to their potency. It assesses the chemical concentration resulting in 50% cytotoxicity (EE-EC50) or the 2-fold increase in IL-1α (IL-1α2x). Four laboratories received 13 coded sensitizers. Reproducible results were obtained in each laboratory. A binary prediction model, EC50≥7 mg/ml=weak to moderate sensitizer and EC50<7 mg/ml=strong to extreme sensitizer had an accuracy of 77%. A superior EE (EC50 and IL-1α2x) correlation was observed with human in vivo DSA05 data compared to LLNA-EC3 data. Human in vivo NOEL and LLNA-EC3 data correlated to a similar extent to in vitro EE data. Our results indicate that this easily transferable EE potency assay is suitable for testing chemical allergens of unknown potencies and may now be ready for further validation, providing complementary potency information to other assays already undergoing validation for assessing skin sensitization potential. PMID:24535238

  17. Effects of pressure anisotropy on magnetospheric magnetohydrodynamics equilibrium of an internal ring current system

    SciTech Connect

    Furukawa, M.

    2014-01-15

    Effects of pressure anisotropy on magnetospheric magnetohydrodynamics equilibrium are studied analytically and numerically, where the plasma is confined by only poloidal magnetic field generated by an internal ring current. The plasma current due to finite pressure can be divided into two components; one remains at isotropic pressure and the other arises from pressure anisotropy. When p{sub ⊥}, the pressure perpendicular to the magnetic field, is larger than p{sub ∥}, the pressure parallel to the magnetic field, those two components of plasma current tend to cancel each other to reduce the total amount of plasma current. Equilibrium beta limit is also examined, where the beta is a ratio of the plasma pressure to the magnetic pressure. The equilibrium beta limit decreases as the pressure anisotropy becomes strong. The beta value is strictly limited by ellipticity of the equilibrium equation when p{sub ∥}>p{sub ⊥}. On the other hand, when p{sub ⊥}>p{sub ∥}, although the tendency of the beta limit agrees with the ellipticity condition of the equilibrium equation, equilibria with a hyperbolic region can be obtained by iterative procedure with practically reasonable convergence criteria.

  18. Sealing device

    SciTech Connect

    Garcia-Crespo, Andres Jose

    2013-12-10

    A sealing device for sealing a gap between a dovetail of a bucket assembly and a rotor wheel is disclosed. The sealing device includes a cover plate configured to cover the gap and a retention member protruding from the cover plate and configured to engage the dovetail. The sealing device provides a seal against the gap when the bucket assemply is subjected to a centrifugal force.

  19. Coining seal

    DOEpatents

    Mancebo, Lloyd

    1976-01-01

    A bakeable high pressure-vacuum seal is provided in which an inductile sealing element having a butterfly shaped crosssection with protruding sharp edges at each of the four corners, is sandwiched between two ductile sealing elements, the sandwiched assembly then being compressed between the surfaces of the flange elements of a high pressure or high vacuum vessel to coin the ductile sealing element into the surface of the inductile sealing element as well as the surfaces of the flange elements.

  20. Rotatable seal assembly

    DOEpatents

    Logan, Clinton M.; Garibaldi, Jack L.

    1982-01-01

    An assembly is provided for rotatably supporting a rotor on a stator so that vacuum chambers in the rotor and stator remain in communication while the chambers are sealed from ambient air, which enables the use of a ball bearing or the like to support most of the weight of the rotor. The apparatus includes a seal device mounted on the rotor to rotate therewith, but shiftable in position on the rotor while being sealed to the rotor as by an O-ring. The seal device has a flat face that is biased towards a flat face on the stator, and pressurized air is pumped between the faces to prevent contact between them while spacing them a small distance apart to avoid the inflow of large amounts of air between the faces and into the vacuum chambers.

  1. Positive fast sealing union connections

    NASA Technical Reports Server (NTRS)

    Kleber, C. M.

    1972-01-01

    Union connections are designed for connecting high pressure flexible hoses from gas storage manifolds to gas transport trailers. Connection uses O ring seals which can be quickly assembled and disassembled without use of wrenches, and which do not twist hose. Worn or damaged O rings are easily replaced.

  2. Mainshaft seals for small gas turbine engines

    NASA Technical Reports Server (NTRS)

    Ludwig, L. P.; Lynwander, P.

    1974-01-01

    An experimental evaluation of mainshaft seals for small gas turbine engines was conducted with shaft speeds to 213 m/s (700 ft/sec), air pressures to 148 Newtons per square centimeter abs. (215 psia), and air temperatures to 412k(282 F). A radial face seal incorporating self-acting geometry for lift augmentation was evaluated. In addition, three conventional carbon seal types (face, circumferential segmented, and rotating ring) were run for comparison. Test results indicated that the conventional seals used in this evaluation may not be satisfactory in future advanced engines because of excessive air leakage. On the other hand, the self-acting face seal was shown to have the potential capability of limiting leakages to one-half that of the conventional face seals and one-fifth that of conventional ring seals. A 150-hour endurance test of the self-acting face seal was conducted.

  3. Total internal reflection mirror-based ultra-sensitive triangular ring resonator sensor on the surface plasmon resonance condition

    NASA Astrophysics Data System (ADS)

    Kim, Hong-Seung; Kim, Tae-Ryong; Kim, Doo-Gun; Choi, Young-Wan

    2015-02-01

    In this paper, we have theoretically analyzed using a finite-difference time domain (FDTD) methods and realized a high sensitive triangular ring resonator sensor based on the total internal reflection (TIR) mirror with a thin metal film for surface plasmon resonance (SPR) phenomenon. One of advantages is a high sensitivity with large phase variation at TIR mirror facet with SPR. Previously, the sensing region of the general ring resonator sensor is located on the cladding region or upper core region. However, the triangular ring resonator has a very high sensitivity using the sensing region of the TIR mirror facet, because the length of the evanescent field at TIR mirror is longer than the evanescent field length at the cladding region. Another is a high Q-factor by the round-trip loss compensation through an active medium in the waveguide. Proposed sensor also has an integrated light source using an InP-based semiconductor optical amplifier. The sensitivity of triangular ring resonator with SPR is extremely enhanced by large phase shift at TIR mirror facet on SPR. Optimized metal thickness is a 33.4 nm at the SPR angle of 22.92 degree. The simulation result of the sensitivity for the triangular ring resonator sensor with SPR is 4.2×104 nm/RIU using by FDTD method. To measure the biosensor, we used an antigen/antibody reaction.

  4. Persistent trigeminal artery arising from the arterial ring/fenestration of the cavernous segment of the internal carotid artery.

    PubMed

    Uchino, Akira; Saito, Naoko; Kurita, Hiroki; Ishihara, Shoichiro

    2012-09-01

    A persistent trigeminal artery (PTA) is the most common carotid-vertebrobasilar anastomosis, usually arising from the cavernous or precavernous segment of the internal carotid artery (ICA) and connecting to the distal basilar artery. There are two types of PTA, lateral and medial. We present the first case of a lateral-type PTA arising from the large arterial ring/fenestration of the cavernous segment of the left ICA with findings from both magnetic resonance angiography and selective catheter angiography. PMID:22215430

  5. Security seal

    DOEpatents

    Gobeli, Garth W.

    1985-01-01

    Security for a package or verifying seal in plastic material is provided by a print seal with unique thermally produced imprints in the plastic. If tampering is attempted, the material is irreparably damaged and thus detectable. The pattern of the imprints, similar to "fingerprints" are recorded as a positive identification for the seal, and corresponding recordings made to allow comparison. The integrity of the seal is proved by the comparison of imprint identification records made by laser beam projection.

  6. Numerical analysis of electrical power generation and internal reforming characteristics in seal-less disk-type solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Shimada, Takanobu; Momma, Akihiko; Takano, Kiyonami; Kato, Tohru

    For seal-less type solid oxide fuel cells, its power generation characteristics and distribution of the gas composition depend on not only the electrochemical reaction, but also complex kinetics and transport phenomena, because the internal reforming reaction and the water-gas shift reaction take place together with reverse diffusion of the ambient gas from the surroundings of the cell. The purpose of this paper is to theoretically explain the experimental results of the anodic concentration profile of gaseous species previously reported in a practical seal-less disk-type cell which used pre-reforming methane with steam as a fuel. A numerical model that takes into account the transport phenomena of the gaseous species and the internal reforming reaction with the water-gas shift reaction together with the assumption of the cell outlet boundary condition was constructed to numerically analyse the gas composition distribution and power generation characteristics. Numerical analyses by the model were conducted for the several cases reported as the experiment. The calculated results in the anode gas concentration profile and in the voltage-current characteristics show good agreement with the experimental data in every case, and then the validity of the simulation model was verified. Therefore, the model is useful for a seal-less disk-type cell which is operated by a fuel including non-reformed methane.

  7. An Experimental Investigation of Leak Rate Performance of a Subscale Candidate Elastomer Docking Space Seal

    NASA Technical Reports Server (NTRS)

    Garafolo, Nicholas G.; Daniels, Christopher C.

    2011-01-01

    A novel docking seal was developed for the main interface seal of NASA s Low Impact Docking System (LIDS). This interface seal was designed to maintain acceptable leak rates while being exposed to the harsh environmental conditions of outer space. In this experimental evaluation, a candidate docking seal assembly called Engineering Development Unit (EDU58) was characterized and evaluated against the Constellation Project leak rate requirement. The EDU58 candidate seal assembly was manufactured from silicone elastomer S0383-70 vacuum molded in a metal retainer ring. Four seal designs were considered with unique characteristic heights. The leak rate performance was characterized through a mass point leak rate method by monitoring gas properties within an internal control volume. The leakage performance of the seals were described herein at representative docking temperatures of -50, +23, and +50 C for all four seal designs. Leak performance was also characterized at 100, 74, and 48 percent of full closure. For all conditions considered, the candidate seal assemblies met the Constellation Project leak rate requirement.

  8. SEALING SIMULATED LEAKS

    SciTech Connect

    Michael A. Romano

    2004-09-01

    This report details the testing equipment, procedures and results performed under Task 7.2 Sealing Simulated Leaks. In terms of our ability to seal leaks identified in the technical topical report, Analysis of Current Field Data, we were 100% successful. In regards to maintaining seal integrity after pigging operations we achieved varying degrees of success. Internal Corrosion defects proved to be the most resistant to the effects of pigging while External Corrosion proved to be the least resistant. Overall, with limitations, pressure activated sealant technology would be a viable option under the right circumstances.

  9. Turbomachine Sealing

    NASA Technical Reports Server (NTRS)

    Hendricks, Robert C.

    1996-01-01

    Designers and customers are demanding higher performance turbomachine systems that have long life between overhauls and satisfy the more restrictive environmental constraints. This overview provides sources of design data, numerical, and experimental results along with selected new seal configurations and static sealing challenges such as in the combustors. The following categories are presented: (1) Seal Rotordynamic Data Base (experimental analytical program at Texas A&M); (2) Secondary Flow Interactions (validation studies at CFDRC, Huntsville AL); (3) Contact Sealing (selected types with finger seal model); and (4) Environmental Constraints (emphasis on combustors).

  10. High-Temperature Seal for Sliding-Gate Valve

    NASA Technical Reports Server (NTRS)

    Leonard, R. G.

    1982-01-01

    Sliding-gate valve originally developed for rocket exhaust-gas ducts is sealed by a Belleville spring. It is simple, compact, and operates over a wider range of temperatures than conventional O-ring sealed valves.

  11. Seal assembly

    SciTech Connect

    Johnson, Roger Neal; Longfritz, William David

    2001-01-01

    A seal assembly that seals a gap formed by a groove comprises a seal body, a biasing element, and a connection that connects the seal body to the biasing element to form the seal assembly. The seal assembly further comprises a concave-shaped center section and convex-shaped contact portions at each end of the seal body. The biasing element is formed from an elastic material and comprises a convex-shaped center section and concave-shaped biasing zones that are opposed to the convex-shaped contact portions. The biasing element is adapted to be compressed to change a width of the seal assembly from a first width to a second width that is smaller than the first width. In the compressed state, the seal assembly can be disposed in the groove. After release of the compressing force, the seal assembly expands. The contact portions will move toward a surface of the groove and the biasing zones will move into contact with another surface of the groove. The biasing zones will bias the contact portions of the seal body against the surface of the groove.

  12. Development of helicopter transmission seals, task 2

    NASA Technical Reports Server (NTRS)

    Hayden, T. S.; Keller, C. H., Jr.

    1973-01-01

    High speed helicopter transmission seal concepts were designed, fabricated and tested. The concepts were a dual element split ring seal and a circumferential seal. The tests were performed in a rig using an actual input quill assembly. The test conditions were selected to simulate transmission operation and were 230 F oil temperature, and a sliding speed of 9400 ft/min. The split ring seal exhibited gross leakage and was considered unsatisfactory, while the circumferential seal leakage was less than 1 c.c./hour; this leakage is within acceptable limits. The circumferential seal wear was only to .0005 inches during a 100 hour run (40 starts and stops). During a 40 hour contamination test (mesh silica flour) the seal total wear was a maximum of .004 inches. This wear is considered acceptable.

  13. 26 CFR 301.7514-1 - Seals of office.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 18 2011-04-01 2011-04-01 false Seals of office. 301.7514-1 Section 301.7514-1... Seals of office. (a) Establishment of seals—(1) Commissioner of Internal Revenue. There is hereby established in and for the office of the Commissioner of Internal Revenue an official seal. The seal...

  14. 26 CFR 301.7514-1 - Seals of office.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 18 2013-04-01 2013-04-01 false Seals of office. 301.7514-1 Section 301.7514-1... Seals of office. (a) Establishment of seals—(1) Commissioner of Internal Revenue. There is hereby established in and for the office of the Commissioner of Internal Revenue an official seal. The seal...

  15. 26 CFR 301.7514-1 - Seals of office.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 18 2014-04-01 2014-04-01 false Seals of office. 301.7514-1 Section 301.7514-1... Seals of office. (a) Establishment of seals—(1) Commissioner of Internal Revenue. There is hereby established in and for the office of the Commissioner of Internal Revenue an official seal. The seal...

  16. 26 CFR 301.7514-1 - Seals of office.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 18 2010-04-01 2010-04-01 false Seals of office. 301.7514-1 Section 301.7514-1... Seals of office. (a) Establishment of seals—(1) Commissioner of Internal Revenue. There is hereby established in and for the office of the Commissioner of Internal Revenue an official seal. The seal...

  17. 26 CFR 301.7514-1 - Seals of office.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 18 2012-04-01 2012-04-01 false Seals of office. 301.7514-1 Section 301.7514-1... Seals of office. (a) Establishment of seals—(1) Commissioner of Internal Revenue. There is hereby established in and for the office of the Commissioner of Internal Revenue an official seal. The seal...

  18. The antiproton interaction with an internal 12C target inside the HESR ring at FAIR

    NASA Astrophysics Data System (ADS)

    Introzzi, R.; Balestra, F.; Lavagno, A.; Scozzi, F.; Younis, H.

    2016-04-01

    In order to fulfill the goal of producing higher rates of doubly strange hyperons, the P¯ANDA collaboration will use the antiproton ring HESR at the future facility FAIR. The low energy hyperon production by an antiproton beam requires to insert a solid target inside the ring. Unwanted side effects of such an insertion are the overwhelming amount of annihilations, which would make the detectors blind, and the fast depletion of the bunch, which circulates inside the ring. The choice of the target material impacts the hyperon production yield: Carbon turned out to provide enough initial hyperon deceleration and keep secondary interactions below a tolerable level. The use of a very thin Diamond target, together with beam steering techniques, seems to be a satisfactory solution to the above problems and will be described hereafter.

  19. PEGASYS---A proposed internal target facility for the PEP storage ring

    SciTech Connect

    Van Biber, K.

    1988-07-01

    A proposal for an integral gas-jet target and forward spectrometer for the PEP storage ring is described. The beam structure, allowable, luminosity (L = 10/sup 33/ cm/sup /minus/2/s/sup /minus/1/ for H/sub 2/, D/sub 2/) and energy (E/sub e/ less than or equal to 15 GeV) make the ring ideal for multiparticle coincidence studies in the scaling regime, and where perturbative QCD may be an apt description of some exclusive and semi-inclusive reactions. 14 refs., 7 figs.

  20. Mars containers - Dust on teflon sealing surfaces

    NASA Astrophysics Data System (ADS)

    Lauer, H. V., Jr.; Allton, J. H.

    As part of an evaluation of suitable hermetic seals for containers for Martian rock and soil samples, teflon o-ring static face seals were challenged with silica gel, basalt, and bentonite dust in several size ranges: 20-45 microns, 45-75 microns, and 75-125 microns. Seals were most tolerant of the soft bentonite dust and least tolerant of angular silica gel dust. Small amounts of 75-125 micron size particles can be accommodated by the teflon o-ring; however, the seals do not work well if smaller particles are concentrated enough to form layers more than 1 grain thick.

  1. Planetary Rings

    NASA Astrophysics Data System (ADS)

    Gordon, M. K.; Araki, S.; Black, G. J.; Bosh, A. S.; Brahic, A.; Brooks, S. M.; Charnoz, S.; Colwell, J. E.; Cuzzi, J. N.; Dones, L.; Durisen, R. H.; Esposito, L. W.; Ferrari, C.; Festou, M.; French, R. G.; Giuliatti-Winter, S. M.; Graps, A. L.; Hamilton, D. P.; Horanyi, M.; Karjalainen, R. M.; Krivov, A. V.; Krueger, H.; Larson, S. M.; Levison, H. F.; Lewis, M. C.; Lissauer, J. J.; Murray, C. D.; Namouni, F.; Nicholson, P. D.; Olkin, C. B.; Poulet, F.; Rappaport, N. J.; Salo, H. J.; Schmidt, J.; Showalter, M. R.; Spahn, F.; Spilker, L. J.; Srama, R.; Stewart, G. R.; Yanamandra-Fisher, P.

    2002-08-01

    The past two decades have witnessed dramatic changes in our view and understanding of planetary rings. We now know that each of the giant planets in the Solar System possesses a complex and unique ring system. Recent studies have identified complex gravitational interactions between the rings and their retinues of attendant satellites. Among the four known ring systems, we see elegant examples of Lindblad and corotation resonances (first invoked in the context of galactic disks), electromagnetic resonances, spiral density waves and bending waves, narrow ringlets which exhibit internal modes due to collective instabilities, sharp-edged gaps maintained via tidal torques from embedded moonlets, and tenuous dust belts created by meteoroid impact onto, or collisions between, parent bodies. Yet, as far as we have come, our understanding is far from complete. The fundamental questions confronting ring scientists at the beginning of the twenty-first century are those regarding the origin, age and evolution of the various ring systems, in the broadest context. Understanding the origin and age requires us to know the current ring properties, and to understand the dominant evolutionary processes and how they influence ring properties. Here we discuss a prioritized list of the key questions, the answers to which would provide the greatest improvement in our understanding of planetary rings. We then outline the initiatives, missions, and other supporting activities needed to address those questions, and recommend priorities for the coming decade in planetary ring science.

  2. Advanced bristle seals for gas turbine engines

    NASA Astrophysics Data System (ADS)

    Cabe, Jerry L.

    1993-01-01

    A seven month proof-of-concept program was conducted for an advanced bristle seal, called a bush seal, for use in gas turbine engines. This program was performed as a Small Business Innovation Research (SBIR) Phase 1 project. Bush seal specimen and a full ring bush seal were designed, evaluated, and manufactured for testing. An analytical study of the potential of the bush seal relative to a labyrinth seal was conducted. Static and dynamic testing of the bush seal was performed to determine the behavior of the bristles under pressurization and during contact with a rotating labyrinth tooth. Stable behavior of the bristle elements was observed during static pressurization of a full ring bush seal. The dynamic testing of various configurations of bush seal against a rotating labyrinth tooth showed minimal wear of the bristles relative to a conventional labyrinth seal. The development and application of the bush seal concept to gas turbine engines has the potential of improving the engine's performance while decreasing the degradation of the seal performance over time.

  3. Radial forces in a misaligned radial face seal

    NASA Technical Reports Server (NTRS)

    Etsion, I.

    1977-01-01

    Radial forces on the primary seal ring of a flat misaligned seal are analyzed, taking into account the radial variation in seal clearance. An analytical solution for both hydrostatic and hydrodynamic effects is presented that covers the whole range from zero to full angular misalignment. The net radial force on the primary seal ring is always directed so as to produce a radial eccentricity which generates inward pumping. Although the radial force is usually very small, in some cases it may be one of the reasons for excessive leakage through both the primary and secondary seals of a radial face seal.

  4. Radial forces in a misaligned radial face seal

    NASA Technical Reports Server (NTRS)

    Etsion, I.

    1978-01-01

    Radial forces on the primary seal ring of a flat misaligned seal are analyzed, taking into account the radial variation in seal clearance. An analytical solution for both hydrostatic and hydrodynamic effects is presented that covers the whole range from zero to full angular misalignment. The net radial force on the primary seal ring is always directed so as to produce a radial eccentricity which generates inward pumping. Although the radial force is usually very small, in some cases it may be one of the reasons for excessive leakage through both the primary and secondary seals of a radial face seal.

  5. Actively controlled shaft seals for aerospace applications

    NASA Technical Reports Server (NTRS)

    Salant, Richard F.

    1991-01-01

    The main objective is to determine the feasibility of utilizing controllable mechanical seals for aerospace applications. A potential application was selected as a demonstration case: the buffer gas seal in a LOX (liquid oxygen) turbopump. Currently, floating ring seals are used in this application. Their replacement with controllable mechanical seals would result in substantially reduced leakage rates. This would reduce the required amount of stored buffer gas, and therefore increase the vehicle payload. For such an application, a suitable controllable mechanical seal was designed and analyzed.

  6. Expanding hollow metal rings

    DOEpatents

    Peacock, Harold B.; Imrich, Kenneth J.

    2009-03-17

    A sealing device that may expand more planar dimensions due to internal thermal expansion of a filler material. The sealing material is of a composition such that when desired environment temperatures and internal actuating pressures are reached, the sealing materials undergoes a permanent deformation. For metallic compounds, this permanent deformation occurs when the material enters the plastic deformation phase. Polymers, and other materials, may be using a sealing mechanism depending on the temperatures and corrosivity of the use. Internal pressures are generated by either rapid thermal expansion or material phase change and may include either liquid or solid to gas phase change, or in the gaseous state with significant pressure generation in accordance with the gas laws. Sealing material thickness and material composition may be used to selectively control geometric expansion of the seal such that expansion is limited to a specific facing and or geometric plane.

  7. Electron Cloud in the Wigglers of the Positron Damping Ring of the International Linear Collider

    SciTech Connect

    Wang, L.; /SLAC

    2007-07-06

    The ILC positron damping ring comprises hundreds of meters of wiggler sections, where many more photons than in the arcs are emitted, and with the smallest beampipe aperture of the ring. A significant electron-cloud density can therefore be accumulated via photo-emission and via beam-induced multipacting. In field-free regions the electron-cloud build up may be suppressed by adding weak solenoid fields, but the electron cloud remaining in the wigglers as well as in the arc dipole magnets can still drive single-bunch and multi-bunch beam instabilities. This paper studies the electron-cloud formation in an ILC wiggler section for various scenarios, as well as its character, and possible mitigation schemes.

  8. High-pressure cryogenic seals for pressure vessels

    NASA Technical Reports Server (NTRS)

    Buggele, A. E.

    1977-01-01

    This investigation of the problems associated with reliably containing gaseous helium pressurized to 1530 bars (22 500 psi) between 4.2 K and 150 K led to the following conclusions: (1) common seal designs used in existing elevated-temperature pressure vessels are unsuitable for high-pressure cryogenic operation, (2) extrusion seal-ring materials such as Teflon, tin, and lead are not good seal materials for cryogenic high-pressure operation; and (3) several high-pressure cryogenic seal systems suitable for large-pressure vessel applications were developed; two seals required prepressurization, and one seal functioned repeatedly without any prepressurization. These designs used indium seal rings, brass or 304 stainless-steel anvil rings, and two O-rings of silicone rubber or Kel-F.

  9. Overview of LIDS Docking and Berthing System Seals

    NASA Technical Reports Server (NTRS)

    Daniels, Christopher C.; Dunlap, Patrick H., Jr.; deGroh, Henry C., III; Steinetz, Bruce M.; Oswald, Jay J.; Smith, Ian

    2007-01-01

    This viewgraph presentation describes the Low Impact Docking System (LIDS) docking and berthing system seals. The contents include: 1) Description of the Application: Low Impact Docking System (LIDS); 2) LIDS Seal Locations: Vehicle Undocked (Hatch Closed); 3) LIDS Seal Locations: Mechanical Pass Thru; 4) LIDS Seal Locations: Electrical and Pyro Connectors; 5) LIDS Seal Locations: Vehicle Docked (Hatches Open); 6) LIDS Seal Locations: Main Interface Seal; 7) Main Interface Seal Challenges and Specifications; 8) Approach; 9) Seal Concepts Under Development/Evaluation; 10) Elastomer Material Evaluations; 11) Evaluation of Relevant Seal Properties; 12) Medium-Scale (12") Gask-O-Seal Compression Tests; 13) Medium-Scale Compression Results; 14) Adhesion Forces of Elliptical Top Gask-o-seals; 15) Medium-Scale Seals; 16) Medium-Scale Leakage Results: Effect of Configuration; 17) Full Scale LIDS Seal Test Rig Development; 18) Materials International Space Station Experiment (MISSE 6A and 6B); and 19) Schedule.

  10. Small High-Speed Self-Acting Shaft Seals for Liquid Rocket Engines

    NASA Technical Reports Server (NTRS)

    Burcham, R. E.; Boynton, J. L.

    1977-01-01

    Design analysis, fabrication, and experimental evaluation were performed on three self-acting facetype LOX seal designs and one circumferential-type helium deal design. The LOX seals featured Rayleigh step lift pad and spiral groove geometry for lift augmentation. Machined metal bellows and piston ring secondary seal designs were tested. The helium purge seal featured floating rings with Rayleigh step lift pads. The Rayleigh step pad piston ring and the spiral groove LOX seals were successfully tested for approximately 10 hours in liquid oxygen. The helium seal was successfully tested for 24 hours. The shrouded Rayleigh step hydrodynamic lift pad LOX seal is feasible for advanced, small, high-speed oxygen turbopumps.

  11. Ferrules seals

    DOEpatents

    Smith, James L.

    1984-01-01

    A device is provided for sealing an inner tube and an outer tube without excessively deforming the tubes. The device includes two ferrules which cooperate to form a vacuum-tight seal between the inner tube and outer tube and having mating surfaces such that overtightening is not possible.

  12. Ferrules seals

    DOEpatents

    Smith, J.L.

    1984-07-10

    A device is provided for sealing an inner tube and an outer tube without excessively deforming the tubes. The device includes two ferrules which cooperate to form a vacuum-tight seal between the inner tube and outer tube and having mating surfaces such that overtightening is not possible. 3 figs.

  13. Metal sealing performance of subsea X-tree wellhead connector sealer

    NASA Astrophysics Data System (ADS)

    Zhao, Honglin; Chen, Rui; Luo, Xiaolan; Duan, Menglan; Lu, Yinghui; Fu, Guowei; Tian, Hongping; Ye, Daohui

    2015-05-01

    The metal sealing performance of subsea X-tree wellhead connectors is crucial for the safety and reliability of subsea X-trees. In order to establish the theoretical relation between metal sealing ring's contact stress and its structural parameters and working pressure, a mechanical analysis method for double-cone sealing of high pressure vessels is applied in analyzing the metal sealing ring under the condition of preload and operation. As a result, the formula of the unit sealing load for the metal sealing ring under operation with residual preload is shown in this paper, which ensures that the metal sealing ring has an excellent sealing effect and can prevent the metal sealing ring from yielding. Besides, while analyzing the sealing process of the metal sealing ring, the change rule of contact stress and working pressure is concluded here, putting forward that the structural parameters of the metal sealing ring are the major factors affecting the change rule. Finally, the analytical solution through theoretical analysis is compared with the simulation result through finite element analysis in a force feedback experiment, and both are consistent with each other, which fully verifies for the design and calculation theory on metal sealing ring's contact stress and its structural parameters and working pressure deduced in this paper. The proposed research will be treated as an applicable theory guiding the design of metal seal for subsea X-tree wellhead connectors.

  14. NanoRocks: Studying Planet Formation and Planetary Rings on the International Space Station

    NASA Astrophysics Data System (ADS)

    Brisset, J.; Colwell, J.; Dove, A.; Maukonen, D.; Brown, N.; Lai, K.; Hoover, B.

    2015-10-01

    We report on the initial results of the NanoRocks experiment on the ISS, which simulates collisions in protoplanetary disks and planetary ring systems. The objective of the NanoRocks experiment is to study low-energy collisions inside systems of multiple mmsized particles of different shapes and materials. In September 2014, NanoRocks reached ISS as part of the NanoRacks platform. First video data from the experiment operations on ISS allows for the measurement of energy damping inside multi-particle systems and the observation of the formation of clusters.

  15. Stabilizing geometry for hydrodynamic rotary seals

    SciTech Connect

    Dietle, Lannie L.; Schroeder, John E.

    2010-08-10

    A hydrodynamic sealing assembly including a first component having first and second walls and a peripheral wall defining a seal groove, a second component having a rotatable surface relative to said first component, and a hydrodynamic seal comprising a seal body of generally ring-shaped configuration having a circumference. The seal body includes hydrodynamic and static sealing lips each having a cross-sectional area that substantially vary in time with each other about the circumference. In an uninstalled condition, the seal body has a length defined between first and second seal body ends which varies in time with the hydrodynamic sealing lip cross-sectional area. The first and second ends generally face the first and second walls, respectively. In the uninstalled condition, the first end is angulated relative to the first wall and the second end is angulated relative to the second wall. The seal body has a twist-limiting surface adjacent the static sealing lip. In the uninstalled condition, the twist-limiting surface is angulated relative to the peripheral wall and varies along the circumference. A seal body discontinuity and a first component discontinuity mate to prevent rotation of the seal body relative to the first component.

  16. Seal for fluid forming tools

    DOEpatents

    Golovashchenko, Sergey Fedorovich; Bonnen, John Joseph Francis

    2012-03-20

    An electro-hydraulic forming tool for forming a sheet metal blank in a one-sided die has first and second rigid rings that engage opposite sides of a sheet metal blank. The rigid rings are contained within slots on a die portion and a hydraulic force applicator portion of the forming tool. The seals are either resiliently biased by an elastomeric member or inherently resiliently biased into contact with the blank.

  17. The sealing performance of a self-sealing pipe flange connection with anaerobic sealants

    SciTech Connect

    Kobayashi, Takashi; Kumakura, Susumu

    1996-12-01

    Deteriorated sealing performance of pipe flange connections is attributable to separation of contacting surfaces between flanges due to high internal pressure or external bending load. In the previous paper, a design concept of a pipe flange connection having self-sealing performance was demonstrated and it was shown that the pipe flange connection has excellent sealing performance under combined loads of internal pressure and external bending moment. However, for simplicity, neither gaskets nor sealants were used in the experiments. For practical application of the self-sealing pipe flange connection, anaerobic sealants were used between the flanges and the sealing performance was tested in this study. Comparisons concerning sealing performance between the self-sealing flange connections and conventional flange connections were made. It is shown that the self-sealing flange connection with anaerobic sealants has the highest sealing performance under combined loads of internal pressure and external bending moment.

  18. Seals cap rotary kiln emissions

    SciTech Connect

    Gunkle, D.W. )

    1993-09-01

    The possibility of producing fugitive emissions is one of the most critical aspects of an incineration system. Whether such a system processes hazardous, medical, mixed or municipal waste, fugitive emissions are of special concern to system operators and the public alike. Effectively designed rotary-kiln seals can reduce fugitive emissions to acceptable, minimal levels. Modern air monitoring systems track incineration site emissions. Possible emissions sources include excavation and transfer sites, storage areas, material-feed systems, rotary kiln seals, and exhaust stacks. Several options are available for rotary-kiln seals. Six are discussed here: labyrinth; overlapping spring plate; graphite block; pneumatic; shrouded; and overpressure. Kiln seals are used to prevent process gases from escaping or ambient air from entering a rotary kiln uncontrolled. They are not designed to function as material seals, or prevent spills of solids or liquids. Seal design involves considering differential pressure produced by a kiln's internal-to-external temperature, pressure excursions (explosions) and material spills.

  19. Advanced helium purge seals for Liquid Oxygen (LOX) turbopumps

    NASA Technical Reports Server (NTRS)

    Shapiro, Wilbur; Lee, Chester C.

    1989-01-01

    Program objectives were to determine three advanced configurations of helium buffer seals capable of providing improved performance in a space shuttle main engine (SSME), high-pressure liquid oxygen (LOX) turbopump environment, and to provide NASA with the analytical tools to determine performance of a variety of seal configurations. The three seal designs included solid-ring fluid-film seals often referred to as floating ring seals, back-to-back fluid-film face seals, and a circumferential sectored seal that incorporated inherent clearance adjustment capabilities. Of the three seals designed, the sectored seal is favored because the self-adjusting clearance features accommodate the variations in clearance that will occur because of thermal and centrifugal distortions without compromising performance. Moreover, leakage can be contained well below the maximum target values; minimizing leakage is important on the SSME since helium is provided by an external tank. A reduction in tank size translates to an increase in payload that can be carried on board the shuttle. The computer codes supplied under this program included a code for analyzing a variety of gas-lubricated, floating ring, and sector seals; a code for analyzing gas-lubricated face seals; a code for optimizing and analyzing gas-lubricated spiral-groove face seals; and a code for determining fluid-film face seal response to runner excitations in as many as five degrees of freedom. These codes proved invaluable for optimizing designs and estimating final performance of the seals described.

  20. Reinforcement core facilitates O-ring installation

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Reinforcement core holds O-ring in place within a structure while adjacent parts are being assembled. The core in the O-ring adds circumferential rigidity to the O-ring material. This inner core does not appreciably affect the sectional elasticity or gland-sealing characteristics of the O-ring.

  1. A diode for accelerating hydrogen nuclides with electron conductivity suppressed by an internal ring magnet

    NASA Astrophysics Data System (ADS)

    Shikanov, A. E.; Vovchenko, E. D.; Kozlovskii, K. I.; Shatokhin, V. L.

    2015-05-01

    We present new experimental data on the acceleration of deuterons in a small-size magnetically insulated diode. Plasma containing deuterons was created at the anode during irradiation of a TiD target by a focused laser beam with a wavelength of 1.06 μm. The accelerating voltage pulse was formed by an Arkadiev-Marx generator. A circular cathode was arranged symmetrically relative to the anode and represented a permanent ring magnet with an inner radius not exceeding 0.02 m and a magnetic induction of up to 0.4 T at the center, which ensured magnetic insulation of the accelerating gap. The experiments showed that the current of accelerated deuterons with energies of up to 300 eV can reach a level of 0.5 kA at pulse durations of ≤0.5 μs.

  2. Gas Path Sealing in Turbine Engines

    NASA Technical Reports Server (NTRS)

    Ludwig, L. P.

    1978-01-01

    A survey of gas path seals is presented with particular attention given to sealing clearance effects on engine component efficiency. The effects on compressor pressure ratio and stall margin are pointed out. Various case-rotor relative displacements, which affect gas path seal clearances, are identified. Forces produced by nonuniform sealing clearances and their effect on rotor stability are discussed qualitatively, and recent work on turbine-blade-tip sealing for high temperature is described. The need for active clearance control and for engine structural analysis is discussed. The functions of the internal-flow system and its seals are reviewed.

  3. Long-term compression effects on elastomeric O-ring behavior

    NASA Technical Reports Server (NTRS)

    Clinton, R. G.; Turner, J. E.

    1990-01-01

    This paper discusses the results of testing performed on elastomeric seal materials that had been under compression for extended periods of time. Elastomeric seals used in the Space Shuttle redesigned solid rocket motors can experience compression times of up to six months. These seals must be capable of sealing internal motor pressure upon ignition. The tests described herein were performed in order to verify that the seals, which had experienced long-term compression could seal throughout motor operation. Testing was divided into two phases: (1) dynamic high pressure testing, and (2) resiliency testing. Dynamic testing was performed using specialized test fixtures that allowed simulation of the field joint movements during initial motor operation along with high pressure gas. Resiliency testing was performed using specialized test fixtures that also simulated field joint movements and also had the ability to measure the sealing force of the O-ring. Results from all testing indicated that the current elastomeric seals used in the redesigned solid rocket motors will seal during motor operations in the currently defined launch environments.

  4. 19 CFR 201.0 - Seal.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 19 Customs Duties 3 2011-04-01 2011-04-01 false Seal. 201.0 Section 201.0 Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION GENERAL RULES OF GENERAL APPLICATION § 201.0 Seal. (a) Pursuant to... Trade Commission has adopted an official seal, the depiction of which follows: EC05OC91.026 (b)...

  5. 19 CFR 201.0 - Seal.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 19 Customs Duties 3 2010-04-01 2010-04-01 false Seal. 201.0 Section 201.0 Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION GENERAL RULES OF GENERAL APPLICATION § 201.0 Seal. (a) Pursuant to... Trade Commission has adopted an official seal, the depiction of which follows: EC05OC91.026 (b)...

  6. 19 CFR 201.0 - Seal.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 19 Customs Duties 3 2013-04-01 2013-04-01 false Seal. 201.0 Section 201.0 Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION GENERAL RULES OF GENERAL APPLICATION § 201.0 Seal. (a) Pursuant to... Trade Commission has adopted an official seal, the depiction of which follows: EC05OC91.026 (b)...

  7. 19 CFR 201.0 - Seal.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 19 Customs Duties 3 2012-04-01 2012-04-01 false Seal. 201.0 Section 201.0 Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION GENERAL RULES OF GENERAL APPLICATION § 201.0 Seal. (a) Pursuant to... Trade Commission has adopted an official seal, the depiction of which follows: EC05OC91.026 (b)...

  8. 19 CFR 201.0 - Seal.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 19 Customs Duties 3 2014-04-01 2014-04-01 false Seal. 201.0 Section 201.0 Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION GENERAL RULES OF GENERAL APPLICATION § 201.0 Seal. (a) Pursuant to... Trade Commission has adopted an official seal, the depiction of which follows: EC05OC91.026 (b)...

  9. Viscoelastic analysis of seals for extended service life

    NASA Technical Reports Server (NTRS)

    Bower, Mark V.

    1993-01-01

    The space station is being developed for a service life of up to thirty years. As a consequence, the design requirements for the seals to be used are unprecedented. Full scale testing to assure the selected seals can satisfy the design requirements are not feasible. As an alternative, a sub-scale test program (2) has been developed by MSFC to calibrate the analysis tools to be used to certify the proposed design. This research has been conducted in support of the MSFC Integrated Seal Test Program. The ultimate objective of this research is to correlate analysis and test results to qualify the analytical tools which in turn, are to be used to qualify the flight hardware. Seals are simple devices, in wide spread use. The most common type of seal is the O-ring. O-ring seals are typically rings of rubber with a circular cross section. The rings are placed between the surfaces to be sealed, usually in a groove of some design. The particular design may differ based on a number of different factors. This research is focused on O-rings that are staticly compressed by perpendicular clamping forces, commonly referred to as face seals. In this type of seal the O-ring is clamped between the sealing surfaces by loads perpendicular to the circular cross section.

  10. Viscoelastic analysis of seals for extended service life

    NASA Astrophysics Data System (ADS)

    Bower, Mark V.

    1993-11-01

    The space station is being developed for a service life of up to thirty years. As a consequence, the design requirements for the seals to be used are unprecedented. Full scale testing to assure the selected seals can satisfy the design requirements are not feasible. As an alternative, a sub-scale test program (2) has been developed by MSFC to calibrate the analysis tools to be used to certify the proposed design. This research has been conducted in support of the MSFC Integrated Seal Test Program. The ultimate objective of this research is to correlate analysis and test results to qualify the analytical tools which in turn, are to be used to qualify the flight hardware. Seals are simple devices, in wide spread use. The most common type of seal is the O-ring. O-ring seals are typically rings of rubber with a circular cross section. The rings are placed between the surfaces to be sealed, usually in a groove of some design. The particular design may differ based on a number of different factors. This research is focused on O-rings that are staticly compressed by perpendicular clamping forces, commonly referred to as face seals. In this type of seal the O-ring is clamped between the sealing surfaces by loads perpendicular to the circular cross section.