Global threat reduction initiative efforts to address transportation challenges associated with the recovery of disused radioactive sealed sources - 10460

International Nuclear Information System (INIS)

Whitworth, Julie; Abeyta, Cristy L.; Griffin, Justin M.; Matzke, James L.; Pearson, Michael W.; Cuthbertson, Abigail; Rawl, Richard; Singley, Paul

2010-01-01

Proper disposition of disused radioactive sources is essential for their safe and secure management and necessary to preclude their use in malicious activities. Without affordable, timely transportation options, disused sealed sources remain in storage at hundreds of sites throughout the country and around the world. While secure storage is a temporary measure, the longer sources remain disused or unwanted the chances increase that they will become unsecured or abandoned. The Global Threat Reduction Initiative's Off-Site Source Recovery Project (GTRIlOSRP), recovers thousands of disused and unwanted sealed sources annually as part of GTRl's larger mission to reduce and protect high risk nuclear and radiological materials located at civilian sites worldwide. Faced with decreasing availability of certified transportation containers to support movement of disused and unwanted neutron- and beta/gamma-emitting radioactive sealed sources, GTRIlOSRP has initiated actions to ensure the continued success of the project in timely recovery and management of sealed radioactive sources. Efforts described in this paper to enhance transportation capabilities include: (sm b ullet) Addition of authorized content to existing and planned Type B containers to support the movement of non-special form and other Type B-quantity sealed sources; (sm b ullet) Procurement of vendor services for the design, development, testing and certification of a new Type B container to support transportation of irradiators, teletherapy heads or sources removed from these devices using remote handling capabilities such as the IAEA portable hot cell facility; (sm b ullet) Expansion of shielded Type A container inventory for transportation of gamma-emitting sources in activity ranges requiring use of shielding for conformity with transportation requirements; (sm b ullet) Approval of the S300 Type A fissile container for transport of Pu-239 sealed sources internationally; (sm b ullet) Technology transfer of

Reactor coolant pump seals: improving their performance

International Nuclear Information System (INIS)

Pothier, N.E.; Metcalfe, R.

1986-06-01

Large CANDU plants are benefitting from transient-resistant four-year reliable reactor coolant pump seal lifetimes, a direct result of AECL's 20-year comprehensive seal improvement program involving R and D staff, manufacturers, and plant designers and operators. An overview of this program is presented, which covers seal modification design, testing, post-service examination, specialized maintenance and quality control. The relevancy of this technology to Light Water Reactor Coolant Pump Seals is also discussed

Mechanical seal monitoring technique by acoustic emission measurements

Energy Technology Data Exchange (ETDEWEB)

Kataoka, Tadashi; Fujita, Yoshihiro; Kawaguchi, Kazunori; Saito, Kazuhiro; Yokota, Setsuo; Hisada, Yasuhide; Masahiro, Komatsu

1987-09-20

This report describes a technique for mechanical seal monitoring through acoustic emission (AE) measurement. The equipment consists of an AE sensor, preamplifier, multiplexer, main amplifier, effective value transducer and computer system. When the sealed liquid pressure undergoes a large change, the seal surface configuration is monitored and evaluated accurately through AE measurement. If the mechanical seal surface id damaged or worn, the AE level is kept high or continues to fluctuate largely for a rather long period. When leak occurs, the AE value shows great fluctuations either at extremely low levels or at high levels. The former trend is considered to result from a decrease in solid contact due to an excessive amount of liquid film being formed at the seal surface during leak. In the latter case, the leak is attributed to severe damage to the seal surface. (18 figs, 1 tab, 5 photos, 3 refs)

Seals and sealing handbook

CERN Document Server

Flitney, Robert K

2007-01-01

Wherever machinery operates there will be seals of some kind ensuring that the machine remains lubricated, the fluid being pumped does not leak, or the gas does not enter the atmosphere. Seals are ubiquitous, in industry, the home, transport and many other places. This 5th edition of a long-established title covers all types of seal by application: static, rotary, reciprocating etc. The book bears little resemblance to its predecessors, and Robert Flitney has re-planned and re-written every aspect of the subject. No engineer, designer or manufacturer of seals can afford to be without this uniq

Sealing a Loosely Fitting Valve Assembly

Science.gov (United States)

Goff, L.; Tellier, G.

1986-01-01

Double-ring seal avoids expense of remachining or redesigning valve parts. Mating fittings on valve sealed by pair of rings - one O-ring and backup ring. Backup ring fills relatively large gap between parts. Prevents softer O-ring from being pushed into and through gap.

TECHNOLOGY ROADMAPPING FOR IAEA SEALS.

Energy Technology Data Exchange (ETDEWEB)

HOFFHEINS,B.; ANNESE,C.; GOODMAN,M.; OCONNOR,W.; GUSHUE,S.; PEPPER,S.

2003-07-13

In the fall of 2002, the U.S. Support Program (USSP) initiated an effort to define a strategy or ''roadmap'' for future seals technologies and to develop a generalized process for planning safeguards equipment development, which includes seals and other safeguards equipment. The underlying objectives of the USSP include becoming more proactive than reactive in addressing safeguards equipment needs, helping the IAEA to maintain an inventory of cost-effective, reliable, and effective safeguards equipment, establishing a long-term planning horizon, and securing IAEA ownership in the process of effective requirements definition and timely transitioning of new or improved systems for IAEA use. At an initial workshop, seals, their functions, performance issues, and future embodiments were discussed in the following order: adhesive seals, metal seals, passive and active loop seals, ultrasonic seals, tamper indicating enclosures (including sample containers, equipment enclosures, and conduits). Suggested improvements to these technologies focused largely on a few themes: (1) The seals must be applied quickly, easily, and correctly; (2) Seals and their associated equipment should not unduly add bulk or weight to the inspectors load; (3) Rapid, in-situ verifiability of seals is desirable; and (4) Seal systems for high risk or high value applications should have two-way, remote communications. Based upon these observations and other insights, the participants constructed a skeletal approach for seals technology planning. The process begins with a top-level review of the fundamental safeguards requirements and extraction of required system features, which is followed by analysis of suitable technologies and identification of technology gaps, and finally by development of a planning schedule for system improvements and new technology integration. Development of a comprehensive procedure will require the partnership and participation of the IAEA. The

Metal and elastomer seal tests for accelerator applications

International Nuclear Information System (INIS)

Welch, K.M.; McIntyre, G.T.; Tuozzolo, J.E.; Skelton, R.; Pate, D.J.; Gill, S.M.

1989-01-01

The vacuum system of the Alternating Gradient Synchrotron (AGS) at Brookhaven National Laboratory has more than a thousand metal vacuum seals. Also, numerous elastomer seals are used throughout the AGS to seal large beam component chambers. An accelerator upgrade program is being implemented to reduce the AGS operating pressure by x100 and improve the reliability of the vacuum system. This paper describes work in progress on metal and elastomer vacuum seals to help meet those two objectives. Tests are reported on the sealing properties of a variety of metal seals used on different sealing surfaces. Results are also given on reversible sorption properties of certain elastomers. 16 refs., 6 figs., 4 tabs

Sealing of investigation boreholes, Phase 4 - Final report

Energy Technology Data Exchange (ETDEWEB)

Pusch, Roland [Drawrite AB, Luleaa Technical University, Luleaa (Sweden); Ramqvist, Gunnar [El-Tekno AB, Figeholm (Sweden); Bockgaard, Niclas [Golder Associates, Goeteborg (Sweden); Ekman, Lennart [LE Geokonsult AB, Baelinge (Sweden)

2011-09-15

The report describes the outcome of Phase 4 of the project 'Sealing of investigation boreholes', which deals with 1) characterization and planning of borehole sealing, 2) performance and quality assessment, 3) sealing of large diameter holes, and 4) interaction of clay and concrete plugs. A specific goal was to find ways to characterize, plan and seal of boreholes so that their impact on the overall hydraulic performance of the repository rock can predicted and controlled. The work comprised selection of representative 'reference holes' at the Laxemar and Forsmark sites for development of a general programme for planning and simulating implementation of borehole plugging campaigns, considering also cost issues. A second aim was to define and quantify the role of seals in the reference holes for finding out how important sealing really is. A third was to test a practical way to seal large diameter boreholes and a fourth to find out how concrete matures and performs in contact with smectite clay. The study demonstrated, in conclusion, the need for developing techniques for preparing deep boreholes before lasting seals are installed in them, since poor sealing can short-circuit hydraulically important fracture zones intersected by the holes. The practically oriented sealing activities showed that the technique developed for tight sealing of large-diameter boreholes is practical and feasible. The issue of chemical stability was investigated by testing the performance and constitution of a plug consisting of CBI concrete in contact with smectite-rich seals for almost three years. This study showed that none of them underwent substantial degradation in this period of time, but chemical reactions and thereby generated changes in physical behaviour of the plug components had taken place, particularly in the clay. The rate of degradation is, however, not yet known. It was concluded from this study that it is suitable to carry out a corresponding

Sealing of investigation boreholes, Phase 4 - Final report

International Nuclear Information System (INIS)

Pusch, Roland; Ramqvist, Gunnar; Bockgaard, Niclas; Ekman, Lennart

2011-09-01

The report describes the outcome of Phase 4 of the project 'Sealing of investigation boreholes', which deals with 1) characterization and planning of borehole sealing, 2) performance and quality assessment, 3) sealing of large diameter holes, and 4) interaction of clay and concrete plugs. A specific goal was to find ways to characterize, plan and seal of boreholes so that their impact on the overall hydraulic performance of the repository rock can predicted and controlled. The work comprised selection of representative 'reference holes' at the Laxemar and Forsmark sites for development of a general programme for planning and simulating implementation of borehole plugging campaigns, considering also cost issues. A second aim was to define and quantify the role of seals in the reference holes for finding out how important sealing really is. A third was to test a practical way to seal large diameter boreholes and a fourth to find out how concrete matures and performs in contact with smectite clay. The study demonstrated, in conclusion, the need for developing techniques for preparing deep boreholes before lasting seals are installed in them, since poor sealing can short-circuit hydraulically important fracture zones intersected by the holes. The practically oriented sealing activities showed that the technique developed for tight sealing of large-diameter boreholes is practical and feasible. The issue of chemical stability was investigated by testing the performance and constitution of a plug consisting of CBI concrete in contact with smectite-rich seals for almost three years. This study showed that none of them underwent substantial degradation in this period of time, but chemical reactions and thereby generated changes in physical behaviour of the plug components had taken place, particularly in the clay. The rate of degradation is, however, not yet known. It was concluded from this study that it is suitable to carry out a corresponding investigation of the plugs

Sealing of boreholes using natural, compatible materials: Granular salt

International Nuclear Information System (INIS)

Finley, R.E.; Zeuch, D.H.; Stormont, J.C.; Daemen, J.J.K.

1994-01-01

Granular salt can be used to construct high performance permanent seals in boreholes which penetrate rock salt formations. These seals are described as seal systems comprised of the host rock, the seal material, and the seal rock interface. The performance of these seal systems is defined by the complex interactions between these seal system components through time. The interactions are largely driven by the creep of the host formation applying boundary stress on the seal forcing host rock permeability with time. The immediate permeability of these seals is dependent on the emplaced density. Laboratory test results suggest that careful emplacement techniques could results in immediate seal system permeability on the order of 10 -16 m 2 to 10 -18 m 2 (10 -4 darcy to 10 -6 ). The visco-plastic behavior of the host rock coupled with the granular salts ability to ''heal'' or consolidate make granular salt an ideal sealing material for boreholes whose permanent sealing is required

Repatriation of disused sealed sources in Peru

International Nuclear Information System (INIS)

Mallaupoma, Mario; Abeyta, Cristy; Matzke, Jim

2013-01-01

Sealed radioactive sources are used around the world in medicine, industry and research within a wide range of applications. Sources may contain a large spectrum of radionuclides, which can have different levels of activity as well as different periods of half-life. At the end of their useful life, they are considered as worn-out or obsolete. However, the residual levels of radioactivity, which have those sources, can be high, representing a high radiation risk. This publication describes the technical actions carried out by the specialized group of the Peruvian Institute of Nuclear energy (IPEN) and Los Alamos National Laboratory which supports the program of 'Global Threat Reduction Initiative's' (GTRI) within the implementation of 'Offsite Source Recovery Program' (OSRP)

Application study of magnetic fluid seal in hydraulic turbine

International Nuclear Information System (INIS)

Yu, Z Y; Zhang, W

2012-01-01

The waterpower resources of our country are abundant, and the hydroelectric power is developed, but at present the main shaft sealing device of hydraulic turbine is easy to wear and tear and the leakage is great. The magnetic fluid seal has the advantages of no contact, no wear, self-healing, long life and so on. In this paper, the magnetic fluid seal would be used in the main shaft of hydraulic turbine, the sealing structure was built the model, meshed the geometry, applied loads and solved by using MULTIPHYSICS in ANSYS software, the influence of the various sealing structural parameters such as tooth width, height, slot width, sealing gap on the sealing property were analyzed, the magnetic fluid sealing device suitable for large-diameter shaft and sealing water was designed, the sealing problem of the hydraulic turbine main shaft was solved effectively which will bring huge economic benefits.

Results from the large scale in situ drift sealing experiment in the salt mine Sondershausen

Energy Technology Data Exchange (ETDEWEB)

Sitz, P.; Koch, G. [Freiberg Univ. of Mining an Technology, Institute of Mining Engineering (Germany); Gruner, M. [Wilsnack and Partners Freiberg / Saxony (Germany)

2003-07-01

The aim of the research, which is supported by the Federal Ministry for Education and Research (Bundesministerium fur Bildung und Forschung) and the state of Thuringia from 1997 to 2003, are long term stable drift sealing systems for underground waste disposals. As a result of the material selection for the sealing element bricks from a mixture of bentonite and quartz-sand were produced. The static abutment was built with natural salt bricks. A real drift sealing system was built in the former potash mine Sondershausen in a depth of 700 m and then tested under a fluid pressure up to 80 bar with saturated salt-brine. The functionality of the bentonite sealing element was proved successfully. Since 1998 some 500 t of such bentonite blocks with sand have been produced and built-in in underground sealing elements in salt mines. (authors)

Main-coolant-pump shaft-seal reliability investigation. Interim report

International Nuclear Information System (INIS)

Fair, C.E.; Marsi, J.A.; Greer, A.O.

1982-09-01

This report contains the results of a survey of reactor coolant pump shaft seal reliability. The survey sample is representatively large (approx. = 27% of total US commercial plant population) and includes the three industry seal suppliers (Bingham-Williamette, Byron Jackson, and Westinghouse). Operationally incurred/induced problems and seal redesign parameters are identified. Failure hypotheses in the form of fault trees have been developed to describe the failure mechanisms. Recommendations are made for seal reliability improvement

Cover-gas seals: 11-LMFBR seal-test program

International Nuclear Information System (INIS)

Steele, O.P. III; Horton, P.H.

1977-01-01

The objective of the Cover Gas Seal Material Development Program is to perform the engineering development required to provide reliable seals for LMFBR application. Specific objectives are to verify the performance of commercial solid cross-section and inflatable seals under reactor environments including radiation, to develop advanced materials and configurations capable of achieving significant improvement in radioactive gas containment and seal temperature capabilities, and to optimize seal geometry for maximum reliability and minimal gas permeation

Tunnel sealing: concept and feasibility evidence

International Nuclear Information System (INIS)

Brenner, R.P.; Eppinger, G.; Mettler, K.

1991-01-01

This report discusses first the aim and purpose of tunnel seals as well as the requirements which should be satisfied. The basic seal concept is a zoned plug consisting of key zones and intermediate zones. The key zones act as barrier elements and will be placed into sections of competent and sound rock. The main function of the intermediate zones is that of a support and the requirements for sealing efficiency may be somewhat relaxed. Three sealing concepts have been devised for both the key zones and the intermediate zones. They differ in the materials used for the seal and in the placement method. For the key zones highly compacted bentonite is recommended, but also cement-based materials, such as standard concrete or prepact concrete are considered suitable. For the intermediate zones, the use of pumped concrete with subsequent grouting of the roof zone is favourable, but also a combination of concrete with a sand/gravel mixture or with properly compacted excavation material is feasible. The concepts introduced can all be realized by conventional tunnelling methods. Excavation by tunnel boring machine is most advantageous as it minimizes disturbance of the rock caused by the cavity-forming process. By employing simple material models, it can be shown that the depth of the excavation disturbed zone can be minimized if support of the tunnel is provided as early as possible after excavation. The cutting of a groove in the tunnel wall along the key zone can further contribute to reduce the depth of the excavation-disturbed zone. In order to ensure the quality of a seal, the quantities of the materials used can be checked and the work procedures to place the seal can be supervised. For the latter the experiences obtained from a large-scale test should be available. Finally, it is also shown that when considering safety analytical aspects, the proposed sealing concepts represent adequate solutions in spite of the probably increased permeability in the excavation

Magnetic fluid seals for DWDM filter manufacturing

International Nuclear Information System (INIS)

Li Zhixin

2002-01-01

Performance requirements of rotary magnetic fluid seals for thin film dense wavelength division multiplexing filter manufacturing are discussed. High speed, large diameter, tight tolerance for rotating accuracy and motion control are some of the technical challenges in this application. Analytical methods for studying these technical issues and experimental data are presented. Innovative design approaches are also discussed. It is shown that using the most advanced magnetic fluid technology and seal design technology, magnetic fluid seals can provide satisfactory performance in this challenging new application

Mechanical seals

CERN Document Server

Mayer, E

1977-01-01

Mechanical Seals, Third Edition is a source of practical information on the design and use of mechanical seals. Topics range from design fundamentals and test rigs to leakage, wear, friction and power, reliability, and special designs. This text is comprised of nine chapters; the first of which gives a general overview of seals, including various types of seals and their applications. Attention then turns to the fundamentals of seal design, with emphasis on six requirements that must be considered: sealing effectiveness, length of life, reliability, power consumption, space requirements, and c

Sealing device

Science.gov (United States)

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.

Sealing Failure Analysis on V-Shaped Sealing Rings of an Inserted Sealing Tool Used for Multistage Fracturing Processes

Directory of Open Access Journals (Sweden)

Gang Hu

2018-06-01

Full Text Available The inserted sealing tool is a critical downhole implement that is used to balance the downhole pressure in multistage fracturing operations and prevent fracturing fluid from overflow and/or backward flow. The sealing ring of an inserted sealing tool plays an important role in downhole sealing since a sealing failure would ail the fracturing operation. In order to improve the sealing performance and reduce the potential fracturing failures, this research aims to investigate the influence of V-shaped sealing ring geometries on sealing performance. Constitutive experiments of rubber materials were carried out and the parameters of the constitutive relationship of rubber materials were obtained. A two-dimensional axisymmetric model considering the sealing ring has been established and influences are investigated with considerations of various system parameters and operating conditions. It is found that the stresses concentrated at the shoulder and inner vertex of the sealing ring have direct impact on the damage of the sealing rings under operational conditions. Moreover, the sealing interference, among several other factors, greatly affects the life of the sealing ring. A new design of the sealing ring is suggested with optimized geometric parameters. Its geometric parameters are the edge height of 5 mm, the vertex angle of 90°–100°, and the interference of 0.1 mm, which show a better performance and prolonged operation life of the sealing ring.

An Integrated Passive (Battery-Free) Seals-and-Tag for International Safeguards

International Nuclear Information System (INIS)

Nekoogar, F.; Dowla, F.

2015-01-01

The ability to reliably and securely automate the monitoring of SNM is an important goal in Safeguards. Although item level monitoring of SNM requires both seal and tag technologies, the two technologies thus far have been developed more or less independently, and had been a lack of an integrated compact system. An integrated seal-and-tag approach not only aids inspectors to perform their tasks effectively, this approach also allows real-time inspection in large scale facilities. A typical facility could be the size of a large warehouse with hundreds or thousands of items that need to be sealed and monitored in real-time. Previously we reported on advanced secure RF passive (battery-less) tags with special features including, long-range interrogation of passive tags, communicating with passive tags with strong encryption and dynamic authentication features, and the ability to place the tags directly on metal objects. In this paper, we report on a novel secure passive tag integrated with fibre optics seal that allows real-time monitoring of items through secure wireless communications that employs AES encryption and dynamic authentication. Furthermore, the devices can be networked for large scale operations. The proposed passive seal has the same capabilities as active seals in that it allows realtime monitoring. However, the battery lifetimes of conventional active seals are limited or unpredictable. As the long-term storage of SNM might last for several years, these passive seals having been integrated with passive RF tags, extends the lifetime of the physical seals and tags indefinitely, while getting the same performance of active seals and tags. The integrated seal-and-tag is transformational in addressing a critical need in Safeguards area for long-term real-time monitoring. (author)

19 CFR 12.63 - Seal-skin or sea-otter-skin waste.

Science.gov (United States)

2010-04-01

... 19 Customs Duties 1 2010-04-01 2010-04-01 false Seal-skin or sea-otter-skin waste. 12.63 Section... OF THE TREASURY SPECIAL CLASSES OF MERCHANDISE Fur-Seal Or Sea-Otter Skins § 12.63 Seal-skin or sea-otter-skin waste. Seal-skin or sea-otter-skin waste composed of small pieces not large enough to be...

The cool seal system: a practical solution to the shaft seal problem and heat related complications with implantable rotary blood pumps.

Science.gov (United States)

Yamazaki, K; Mori, T; Tomioka, J; Litwak, P; Antaki, J F; Tagusari, O; Koyanagi, H; Griffith, B P; Kormos, R L

1997-01-01

A critical issue facing the development of an implantable, rotary blood pump is the maintenance of an effective seal at the rotating shaft. Mechanical seals are the most versatile type of seal in wide industrial applications. However, in a rotary blood pump, typical seal life is much shorter than required for chronic support. Seal failure is related to adhesion and aggregation of heat denatured blood proteins that diffuse into the lubricating film between seal faces. Among the blood proteins, fibrinogen plays an important role due to its strong propensity for adhesion and low transition temperature (approximately 50 degrees C). Once exposed to temperature exceeding 50 degrees C, fibrinogen molecules fuse together by multi-attachment between heat denatured D-domains. This quasi-polymerized fibrin increases the frictional heat, which proliferates the process into seal failure. If the temperature of the seal faces is maintained well below 50 degrees C, a mechanical seal would not fail in blood. Based on this "Cool-Seal" concept, we developed a miniature mechanical seal made of highly thermally conductive material (SiC), combined with a recirculating purge system. A large supply of purge fluid is recirculated behind the seal face to augment convective heat transfer to maintain the seal temperature below 40 degrees C. It also cools all heat generating pump parts (motor coil, bearing, seal). The purge consumption has been optimized to virtually nil (seal system has now been incorporated into our intraventricular axial flow blood pump (IVAP) and newly designed centrifugal pump. Ongoing in vivo evaluation of these systems has demonstrated good seal integrity for more than 160 days. The Cool-Seal system can be applied to any type of rotary blood pump (axial, diagonal, centrifugal, etc.) and offers a practical solution to the shaft seal problem and heat related complications, which currently limit the use of implantable rotary blood pumps.

Cover gas seals: FFTF-LMFBR seal test program

International Nuclear Information System (INIS)

Kurzeka, W.; Oliva, R.; Welch, T.S.; Shimazaki, T.

1974-01-01

The objectives of this program are to: (1) conduct static and dynamic tests to demonstrate or determine the mechanical performance of full-size (cross section) FFTF fuel transfer machine and reactor vessel head seals intended for use in a sodium vapor-inert gas environment, (2) demonstrate that these FFTF seals or new seal configurations provide acceptable fission product and cover gas retention capabilities at Clinch River Breeder Reactor Plant (CRBRP) operating environmental conditions other than radiation, and (3) develop improved seals and seal technology for the CRBRP to support the national objective to reduce all atmospheric contaminations to low levels

Failure analysis and seal life prediction for contacting mechanical seals

Science.gov (United States)

Sun, J. J.; He, X. Y.; Wei, L.; Feng, X.

2008-11-01

Fault tree analysis method was applied to quantitatively investigate the causes of the leakage failure of mechanical seals. It is pointed out that the change of the surface topography is the main reasons causing the leakage of mechanical seals under the condition of constant preloads. Based on the fractal geometry theory, the relationship between the surface topography and working time were investigated by experiments, and the effects of unit load acting on seal face on leakage path in a mechanical seal were analyzed. The model of predicting seal life of mechanical seals was established on the basis of the relationship between the surface topography and working time and allowable leakage. The seal life of 108 mechanical seal operating at the system of diesel fuel storage and transportation was predicted and the problem of the condition monitoring for the long-period operation of mechanical seal was discussed by this method. The research results indicate that the method of predicting seal life of mechanical seals is feasible, and also is foundation to make scheduled maintenance time and to achieve safe-reliability and low-cost operation for industrial devices.

Ceramic Seal.

Energy Technology Data Exchange (ETDEWEB)

Smartt, Heidi A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Romero, Juan A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Custer, Joyce Olsen [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hymel, Ross W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Krementz, Dan [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Gobin, Derek [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Harpring, Larry [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Martinez-Rodriguez, Michael [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Varble, Don [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); DiMaio, Jeff [Tetramer Technologies, Pendleton, SC (United States); Hudson, Stephen [Tetramer Technologies, Pendleton, SC (United States)

2016-11-01

Containment/Surveillance (C/S) measures are critical to any verification regime in order to maintain Continuity of Knowledge (CoK). The Ceramic Seal project is research into the next generation technologies to advance C/S, in particular improving security and efficiency. The Ceramic Seal is a small form factor loop seal with improved tamper-indication including a frangible seal body, tamper planes, external coatings, and electronic monitoring of the seal body integrity. It improves efficiency through a self-securing wire and in-situ verification with a handheld reader. Sandia National Laboratories (SNL) and Savannah River National Laboratory (SRNL), under sponsorship from the U.S. National Nuclear Security Administration (NNSA) Office of Defense Nuclear Nonproliferation Research and Development (DNN R&D), have previously designed and have now fabricated and tested Ceramic Seals. Tests have occurred at both SNL and SRNL, with different types of tests occurring at each facility. This interim report will describe the Ceramic Seal prototype, the design and development of a handheld standalone reader and an interface to a data acquisition system, fabrication of the seals, and results of initial testing.

Ceramic Seal

International Nuclear Information System (INIS)

Smartt, Heidi A.; Romero, Juan A.; Custer, Joyce Olsen; Hymel, Ross W.; Krementz, Dan; Gobin, Derek; Harpring, Larry; Martinez-Rodriguez, Michael; Varble, Don; DiMaio, Jeff; Hudson, Stephen

2016-01-01

Containment/Surveillance (C/S) measures are critical to any verification regime in order to maintain Continuity of Knowledge (CoK). The Ceramic Seal project is research into the next generation technologies to advance C/S, in particular improving security and efficiency. The Ceramic Seal is a small form factor loop seal with improved tamper-indication including a frangible seal body, tamper planes, external coatings, and electronic monitoring of the seal body integrity. It improves efficiency through a self-securing wire and in-situ verification with a handheld reader. Sandia National Laboratories (SNL) and Savannah River National Laboratory (SRNL), under sponsorship from the U.S. National Nuclear Security Administration (NNSA) Office of Defense Nuclear Nonproliferation Research and Development (DNN R&D), have previously designed and have now fabricated and tested Ceramic Seals. Tests have occurred at both SNL and SRNL, with different types of tests occurring at each facility. This interim report will describe the Ceramic Seal prototype, the design and development of a handheld standalone reader and an interface to a data acquisition system, fabrication of the seals, and results of initial testing.

Synthesis of Large-Scale Single-Crystalline Monolayer WS2 Using a Semi-Sealed Method

Directory of Open Access Journals (Sweden)

Feifei Lan

2018-02-01

Full Text Available As a two-dimensional semiconductor, WS2 has attracted great attention due to its rich physical properties and potential applications. However, it is still difficult to synthesize monolayer single-crystalline WS2 at larger scale. Here, we report the growth of large-scale triangular single-crystalline WS2 with a semi-sealed installation by chemical vapor deposition (CVD. Through this method, triangular single-crystalline WS2 with an average length of more than 300 µm was obtained. The largest one was about 405 μm in length. WS2 triangles with different sizes and thicknesses were analyzed by optical microscope and atomic force microscope (AFM. Their optical properties were evaluated by Raman and photoluminescence (PL spectra. This report paves the way to fabricating large-scale single-crystalline monolayer WS2, which is useful for the growth of high-quality WS2 and its potential applications in the future.

Mechanical seal assembly

Science.gov (United States)

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.

Mechanical Seal Assembly

Energy Technology Data Exchange (ETDEWEB)

Kotlyar, Oleg M.

1999-06-18

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.

Glass sealing

Energy Technology Data Exchange (ETDEWEB)

Brow, R.K.; Kovacic, L.; Chambers, R.S. [Sandia National Labs., Albuquerque, NM (United States)

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.

Sealing properties of cement-based grout materials used in the rock sealing project

Energy Technology Data Exchange (ETDEWEB)

Onofrei, M; Gray, M N; Pusch, R; Boergesson, L; Karnland, O; Shenton, B; Walker, B

1993-12-01

The Task Force on Sealing Materials and Techniques of the Stripa Project recommended that work be undertaken to study the sealing properties of cement-based grout materials. A new class of cement-based grouts (high-performance grouts) with the ability to penetrate and seal fine fractures in granite was investigated. The materials were selected for their small mean particle size and the ability to be made fluid by a superplasticizer at low water/cementitious-materials ratios. The fundamental physical and chemical properties (such as the particle size and chemical composition) of the materials were evaluated. The rheological properties of freshly mixed grouts, which control the workability of the grouts, were determined together with the properties of hardened materials, which largely control the long-term performance (longevity) of the materials in repository settings. The materials selected were shown to remain gel-like during the setting period, and so the grouts may be expected to remain largely homogenous during and after injection into the rock without separating into solid and liquid phases. The hydraulic conductivity and strength of hardened grouts were determined. The microstructure of the bulk grouts was characterized by a high degree of homogeneity with extremely fine porosity. The low hydraulic conductivity and good mechanical properties are consistent with the extremely fine porosity. The ability of the fractured grouts to self-seal was also observed in tests in which the hydraulic conductivity of recompacted granulated grouts was determined. The laboratory tests were carried out in parallel with investigations of the in situ performance of the materials and with the development of geochemical and theoretical models for cement-based grout longevity. (author). 56 refs., 15 tabs., 98 figs.

Sealing properties of cement-based grout materials used in the rock sealing project

International Nuclear Information System (INIS)

Onofrei, M.; Gray, M.N.; Pusch, R.; Boergesson, L.; Karnland, O.; Shenton, B.; Walker, B.

1993-12-01

The Task Force on Sealing Materials and Techniques of the Stripa Project recommended that work be undertaken to study the sealing properties of cement-based grout materials. A new class of cement-based grouts (high-performance grouts) with the ability to penetrate and seal fine fractures in granite was investigated. The materials were selected for their small mean particle size and the ability to be made fluid by a superplasticizer at low water/cementitious-materials ratios. The fundamental physical and chemical properties (such as the particle size and chemical composition) of the materials were evaluated. The rheological properties of freshly mixed grouts, which control the workability of the grouts, were determined together with the properties of hardened materials, which largely control the long-term performance (longevity) of the materials in repository settings. The materials selected were shown to remain gel-like during the setting period, and so the grouts may be expected to remain largely homogenous during and after injection into the rock without separating into solid and liquid phases. The hydraulic conductivity and strength of hardened grouts were determined. The microstructure of the bulk grouts was characterized by a high degree of homogeneity with extremely fine porosity. The low hydraulic conductivity and good mechanical properties are consistent with the extremely fine porosity. The ability of the fractured grouts to self-seal was also observed in tests in which the hydraulic conductivity of recompacted granulated grouts was determined. The laboratory tests were carried out in parallel with investigations of the in situ performance of the materials and with the development of geochemical and theoretical models for cement-based grout longevity. (author). 56 refs., 15 tabs., 98 figs

Rotary plug seal

International Nuclear Information System (INIS)

Ito, Koji; Abiko, Yoshihiro.

1981-01-01

Purpose: To enable fuel exchange even upon failure of regular seals and also to enable safety seal exchange by the detection of the reduction in the contact pressure of a rotary plug seal. Constitution: If one of a pair of regular tube seals for the rotary plug is failed during ordinary operation of a FBR type reactor, the reduction in the contact pressure of the seal to the plug gibbousness is detected by a pressure gauge and a solenoid valve is thereby closed. Thus, a back-up-tube seal provided above or below the tube seal is press-contacted by way of argon gas to the gibbousness to enter into operation state and lubricants are supplied from an oil tank. In such a structure, the back-up-tube seal is operated before the failure of the tube seal to enable to continue the fuel exchange work, as well as safety exchange for the tube seal. (Moriyama, K.)

Reactor coolant pump seal leakage monitoring

International Nuclear Information System (INIS)

Stevens, D.M.; Spencer, J.W.; Morris, D.J.; James, W.; Shugars, H.G.

1986-01-01

Problems with reactor coolant pump seals have historically accounted for a large percentage of unscheduled outages. Studies performed for the Electric Power Research Institute (EPRI) have shown that the replacement of coolant pump seals has been one of the leading causes of nuclear plant unavailability over the last ten years. Failures of coolant pump seals can lead to primary coolant leakage rates of 200-500 gallons per minute into the reactor building. Airborne activity and high surface contamination levels following these failures require a major cleanup effort and increases the time and personnel exposure required to refurbish the pump seals. One of the problems in assessing seal integrity is the inability to accurately measure seal leakage. Because seal leakage flow is normally very small, it cannot be sensed directly with normal flow instrumentation, but must be inferred from several other temperature and flow measurements. In operating plants the leakage rate has been quantified with a tipping-bucket gauge, a device which indicates when one quart of water has been accumulated. The tipping-bucket gauge has been used for most rainfall-intensity monitoring. The need for a more accurate and less expensive gauge has been addressed. They have developed a drop-counter precipitation sensor has been developed and optimized. The applicability of the drop-counter device to the problem of measuring seal leakage is being investigated. If a review of system specification and known drop-counter performance indicates that this method is feasible for measuring seal leak rates, a drop-counter gauge will be fabricated and tested in the laboratory. If laboratory tests are successful the gauge will be demonstrated in a pump test loop at Ontario Hydro and evaluated under simulated plant conditions. 3 references, 2 figures

POPULATION NUMBERS OF FUR SEALS AT PRINCE EDWARD ...

African Journals Online (AJOL)

At a mean intrinsic rate of natural increase of 16.2% per year, Antarctic fur seals appear to be in the rapid recolonization phase of population growth. Breeding colonies of Subantarctic fur seals, largely found on the entire east coast, produced an estimated 15 000 pups, and the population had maintained a mean intrinsic ...

Sealing performance of a magnetic fluid seal for rotary blood pumps.

Science.gov (United States)

Mitamura, Yoshinori; Takahashi, Sayaka; Kano, Kentaro; Okamoto, Eiji; Murabayashi, Shun; Nishimura, Ikuya; Higuchi, Taka-Aki

2009-09-01

A magnetic fluid (MF) for a rotary blood pump seal enables mechanical contact-free rotation of the shaft and, hence, has excellent durability. The performance of a MF seal, however, has been reported to decrease in liquids. We have developed a MF seal that has a "shield" mechanism and a new MF with a higher magnetization of 47.9 kA/m. The sealing performance of the MF seal installed in a rotary blood pump was studied. Under the condition of continuous flow, the MF seal remained in perfect condition against a pressure of 298 mm Hg (pump flow rate: 3.96 L/min). The seal was also perfect against a pressure of 170 mm Hg in a continuous flow of 3.9 L/min for 275 days. We have developed a MF seal that works in liquid against clinically used pressures. The MF seal is promising as a shaft seal for rotary blood pumps.

Design of Active Magnetic Bearing Controllers for Rotors Subjected to Gas Seal Forces

DEFF Research Database (Denmark)

Lauridsen, Jonas Skjødt; Santos, Ilmar F.

2018-01-01

Proper design of feedback controllers is crucial for ensuring high performance of Active Magnetic Bearing (AMB) supported rotor dynamic systems. Annular seals in those systems can contribute with significant forces, which, in many cases, are hard to model in advance due to complex geometries...... of the seal and multiphase fluids. Hence, it can be challenging to design AMB controllers that will guarantee robust performance for these kinds of systems. This paper demonstrates the design, simulation and experimental results of model based controllers for AMB systems, subjected to dynamic seal forces....... The controllers are found using H-infinity - and µ synthesis and are based on a global rotor dynamic model in-which the seal coefficients are identified in-situ. The controllers are implemented in a rotor-dynamic test facility with two radial AMBs and one annular seal with an adjustable inlet pressure. The seal...

Salt brickwork as long-term sealing in salt formations

International Nuclear Information System (INIS)

Walter, F.; Yaramanci, U.

1993-01-01

Radioactive wastes can be disposed of in deep salt formations. Rock salt is a suitable geologic medium because of its unique characteristics. Open boreholes, shafts and drifts are created to provide physical access to the repository. Long-term seals must be emplaced in these potential pathways to prevent radioactive release into the biosphere. The sealing materials must be mechanically and, most important, geochemically stable within the host rock. Salt bricks made from compressed salt-powder are understood to be the first choice long-term sealing material. Seals built of salt bricks will be ductile. Large sealing systems are built by combining the individual bricks with mortar. Raw materials for mortar are fine-grained halite powder and ground saliferous clay. This provides for the good adhesive strength of the mortar to the bricks and the high shear-strength of the mortar itself. To test the interaction of rock salt with an emplaced long-term seal, experiments will be carried out in situ, in the Asse salt mine in Germany. Simple borehole sealing experiments will be performed in horizontal holes and a complicated drift sealing experiment is planned, to demonstrate the technology of sealing a standard size drift or shaft inside a disturbed rock mass. Especially, the mechanical stability of the sealing system has to be demonstrated

Electronic self-monitoring seal

International Nuclear Information System (INIS)

Campbell, J.W.

1978-01-01

The Electronic Self-Monitoring Seal is a new type of security seal which allows continuous verification of the seal's identity and status. The identity information is a function of the individual seal, time, and seal integrity. A description of this seal and its characteristics are presented. Also described are the use cycle for the seal and the support equipment for programming and verifying the seal

Inboard seal mounting

Science.gov (United States)

Hayes, John R. (Inventor)

1983-01-01

A regenerator assembly for a gas turbine engine has a hot side seal assembly formed in part by a cast metal engine block having a seal recess formed therein that is configured to supportingly receive ceramic support blocks including an inboard face thereon having a regenerator seal face bonded thereto. A pressurized leaf seal is interposed between the ceramic support block and the cast metal engine block to bias the seal wear face into sealing engagement with a hot side surface of a rotary regenerator matrix.

Security seal

Science.gov (United States)

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.

Reactor coolant pump shaft seal behavior during blackout conditions

International Nuclear Information System (INIS)

Mings, W.J.

1985-01-01

The United States Nuclear Regulatory Commission has classified the problem of reactor coolant pump seal failures as an unresolved safety issue. This decision was made in large part due to experimental results obtained from a research program developed to study shaft seal performance during station blackout and reported in this paper. Testing and analysis indicated a potential for pump seal failure under postulated blackout conditions leading to a loss of primary coolant with a concomitant danger of core uncovery. The work to date has not answered all the concerns regarding shaft seal failure but it has helped scope the problem and focus future research needed to completely resolve this issue

Mechanical seal program

International Nuclear Information System (INIS)

Lowery, G.B.

1983-01-01

The experimental plans and timing for completion of the mechanical seal program for both the slurry and transfer pumps are given. The slurry pump seal program will be completed by April 1984 with turnover of two seals in pumps to SRP Tank 15H. Transfer pump seal design will be released for plant use by May 1984. Also included are various other pump and seal related tests

Secondary seal effects in hydrostatic non-contact seals for reactor coolant pump shaft

International Nuclear Information System (INIS)

Fujita, T.; Koga, T.; Tanoue, H.; Hirabayashi, H.

1987-01-01

The paper presents a seal flow analysis in a hydrostatic non-contact seal for a PWR coolant pump shaft. A description is given of the non-contact seal for the reactor coolant pump. Results are presented for a distortion analysis of the seal ring, along with the seal flow characteristics and the contact pressure profiles of the secondary seals. The results of the work confirm previously reported findings that the seal ring distortion is sensitive to the o-ring location (which was placed between the ceramic seal face and the seal ring retainer). The paper concludes that the seal flow characteristics and the tracking performance depend upon the dynamic properties of the secondary seal. (U.K.)

Design optimization of seal structure for sealing liquid by magnetic fluids

International Nuclear Information System (INIS)

Liu Tonggang; Cheng Yusheng; Yang Zhiyi

2005-01-01

The durability of the magnetic fluid seal clearly decreases when sealing another liquid because of the interface instability caused by the applied magnetic field and the velocity difference of the two liquids. With an intention to establish a stable interface during sealing liquid, a new magnetic fluid seal was developed in this paper. The parameters of the structure were optimized by a simulation apparatus. And the magnetic fluid seal designed based on the optimum parameters shows good performance and long life for sealing lubricating oil

Technological progress in sealed lead/acid batteries

Science.gov (United States)

Yamashita, J.; Nakashima, H.; Kasai, Y.

A brief review is given of the history of the research and development of sealed lead/acid batteries during the 30 years since, in 1959, the Yuasa Battery Co. introduced a small-sized sealed battery as the power supply for portable television sets. In 1965, Yuasa began the full-scale mass production and sale of a small-sized sealed lead/acid battery under the NOYPER brand. In 1970, the use of a PbCa alloy grid was adopted, and there followed the successful development of a sealed battery with an oxygen-recombination facility. In 1976, Yuasa more or less established the basic technology for the valve-regulated sealed lead/acid battery — the NP battery — which is now the type in general use. Throughout the 1980s, Yuasa, has continued development in order to expand the sphere of application for the production technology of valve-regulated batteries for motorcycles, as well as for stationary duties with large capacities of 100 to 3000 A h. Recently, in order to improve the reliability and boost the output of sealed lead/acid batteries for employment in UPS power sources, Yuasa has been working intently on the design of a valve-regulated lead/acid battery with outstanding characteristics for high-rate discharge and resistance to high temperatures.

Seal arrangement

International Nuclear Information System (INIS)

Dempsey, J.D.

1978-01-01

A hydraulically balanced face type shaft seal is provided in which the opening and closing seal face areas retain concentricity with each other in the event of lateral shaft displacement. The seal arrangement is for a vertical high pressure pump, indented for use in the cooling system of a nuclear reactor. (Auth.)

Seroprevalence of Antibodies against Seal Influenza A(H10N7) Virus in Harbor Seals and Gray Seals from the Netherlands.

Science.gov (United States)

Bodewes, Rogier; Rubio García, Ana; Brasseur, Sophie M; Sanchez Conteras, Guillermo J; van de Bildt, Marco W G; Koopmans, Marion P G; Osterhaus, Albert D M E; Kuiken, Thijs

2015-01-01

In the spring and summer 2014, an outbreak of seal influenza A(H10N7) virus infection occurred among harbor seals (Phoca vitulina) off the coasts of Sweden and Denmark. This virus subsequently spread to harbor seals off the coasts of Germany and the Netherlands. While thousands of seals were reported dead in Sweden, Denmark and Germany, only a limited number of seals were found dead in the Netherlands. To determine the extent of exposure of seals in the Netherlands to influenza A/H10N7 virus, we measured specific antibody titers in serum samples from live-captured seals and seals admitted for rehabilitation in the Netherlands by use of a hemagglutination inhibition assay and an ELISA. In harbor seals in 2015, antibodies against seal influenza A(H10N7) virus were detected in 41% (32 out of 78) pups, 10% (5 out of 52) weaners, and 58% (7 out of 12) subadults or adults. In gray seals (Halichoerus grypus) in 2015, specific antibodies were not found in the pups (n = 26), but in 26% (5 out of 19) of the older animals. These findings indicate that, despite apparent low mortality, infection with seal influenza A(H10N7) virus was geographically widespread and also occurred in grey seals.

Perfluorinated contaminants in fur seal pups and penguin eggs from South Shetland, Antarctica.

Science.gov (United States)

Schiavone, A; Corsolini, S; Kannan, K; Tao, L; Trivelpiece, W; Torres, D; Focardi, S

2009-06-01

Perfluorinated compounds (PFCs) have emerged as a new class of global environmental pollutants. In this study, the presence of perfluorochemicals (PFCs) in penguin eggs and Antarctic fur seals was reported for the first time. Tissue samples from Antarctic fur seal pups and penguin eggs were collected during the 2003/04 breeding season. Ten PFC contaminants were determined in seal and penguin samples. The PFC concentrations in seal liver were in the decreasing order, PFOS>PFNA>PFHpA>PFUnDA while in Adélie penguin eggs were PFHpA>PFUnDA>PFDA>PFDoDA, and in Gentoo penguin eggs were PFUnDA>PFOS>PFDoDA>PFHpA. The PFC concentrations differed significantly between seals and penguins (ppenguins (ppenguin eggs of 0.3 ng/g and 0.38 ng/g wet wt, respectively. PFCs detected in penguin eggs and seal pups suggested oviparous and viviparous transfer of PFOS to eggs and off-springs.

Seal design alternatives study

International Nuclear Information System (INIS)

Van Sambeek, L.L.; Luo, D.D.; Lin, M.S.; Ostrowski, W.; Oyenuga, D.

1993-06-01

This report presents the results from a study of various sealing alternatives for the WIPP sealing system. Overall, the sealing system has the purpose of reducing to the extent possible the potential for fluids (either gas or liquid) from entering or leaving the repository. The sealing system is divided into three subsystems: drift and panel seals within the repository horizon, shaft seals in each of the four shafts, and borehole seals. Alternatives to the baseline configuration for the WIPP seal system design included evaluating different geometries and schedules for seal component installations and the use of different materials for seal components. Order-of-magnitude costs for the various alternatives were prepared as part of the study. Firm recommendations are not presented, but the advantages and disadvantages of the alternatives are discussed. Technical information deficiencies are identified and studies are outlined which can provide required information

A novel conservative approach combining “SealBio” and “Surgical Fenestration” for healing of large periapical cystic lesions of endodontic origin: A pilot study

Directory of Open Access Journals (Sweden)

Naseem Shah

2017-01-01

Full Text Available Objectives: To evaluate the treatment outcome of large periapical cystic lesions treated by combining two novel, conservative approaches, “SealBio” and “Surgical Fenestration”. Materials and Methods: Five cases (4M:1F, age range 14-38 years, mean age 24.5 years of large periapical cystic lesions, diagnosed on clinical and radiographic examination, were included in the study. After informed consent, endodontic treatment was initiated; chemo-mechanical preparation and intra-canal dressing of calcium hydroxide was given. At the next sitting after one week, further disinfection root canals was done by “apical clearing”, “apical foramen widening” and irrigation. A cotton pellet was kept in the access cavity. After local anaesthesia, full thickness muco-periosteal flap was reflected and the thinned out bone was removed with bone rongers, a small piece of cystic lining was excised and the cystic cavity was copiously flushed with Betadine solution. The remaining cystic lining was gently curetted and the flap was sutured back. “SealBio” was performed after gentle irrigation with saline and intentional over instrumentation. A calcium sulphate based cement was pushed in the cervical third of the canal and the access opening was sealed with glass ionomer cement. Patient was prescribed antibiotics and anti-inflammatory drugs for 5 days and sutures were removed after 7 days. Patients were followed up clinically and radiographically at regular intervals. Conclusions: In this pilot study, treatment outcome after combined technique of “SealBio” and “Surgical fenestration” was found to be highly effective in healing of large periapical cystic lesions. It was simple to perform and very conservative treatment; it required minimal bone removal, obviated the need for complete cyst enucleation, apicectomy and retrograde filling.

Nuclear waste vault sealing

International Nuclear Information System (INIS)

Gyenge, M.

1980-01-01

A nuclear waste vault must be designed and built to ensure adequate isolation of the nuclear wastes from human contact. Consequently, after a vault has been fully loaded, it must be adequately sealed off to prevent radionuclide migration which may be provided by circulating groundwater. Vault sealing entails four major aspects, i.e.: (a) vault grouting; (b) borehole sealing; (c) buffer packing; and (d) backfilling. Of particular concern in vault sealing are the physical and chemical properties of the sealing material, its long-term durability and stability, and the techniques used for its emplacement. Present sealing technology and sealing materials are reviewed in terms of the particular needs of vault sealing. Areas requiring research and development are indicated

Nozzle seal

International Nuclear Information System (INIS)

Herman, R.F.

1977-01-01

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

Nozzle seal

International Nuclear Information System (INIS)

Walling, G.A.

1977-01-01

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 rings operatively disposed between the outlet nozzles and the hoop. The sealing rings connected by flexible members are biased against the pressure vessel and the hoop, 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. 4 claims, 2 figures

Factors Affecting Haul-Out Behavior of Harbor Seals (Phoca vitulina in Tidewater Glacier Inlets in Alaska: Can Tourism Vessels and Seals Coexist?

Directory of Open Access Journals (Sweden)

Gail M Blundell

Full Text Available Large numbers of harbor seals (Phoca vitulina use habitat in tidewater glaciers in Alaska for pupping, breeding, and molting. Glacial fjords are also popular tourist destinations; however, visitation by numerous vessels can result in disturbance of seals during critical life-history phases. We explored factors affecting haul-out behavior of harbor seals at a glacial site frequented by tourism vessels. In 2008-10, we deployed VHF transmitters on 107 seals in Endicott Arm, Alaska. We remotely monitored presence and haul-out behavior of tagged seals and documented vessel presence with time-lapse cameras. We evaluated the influence of environmental and physical factors on the probability of being hauled out, duration of haul-out bouts, and as factors associated with the start and end of a haulout. Location, season, hour, and interactions of location by year, season, hour, and sex significantly influenced haul-out probability, as did ice, weather, and vessels. Seals were more likely to be hauled out with greater ice availability during the middle of the day, and less likely to be hauled out if vessels were present. Cruise ships had the strongest negative effect; however, most vessel types negatively affected haul-out probability. Haul-out duration was longest in association with starting on incoming tides, clear skies, no precipitation, occurring in the middle of the day, and ending in the late afternoon or evening. End of haulouts was associated with increasing cloud cover, low ice availability, and vessel presence; large-sized tourism vessels or all-vessel-types combined were significant predictors of ending a haul-out bout. Probability of being hauled out was highest in June, during pupping season. Potential disturbances of harbor seals could be reduced, enabling longer resting times for seals and fewer interruptions for nursing pups, if vessels focused the majority of visits to glacial habitat to before or after the hours of 08:00-17:00 or, less

Factors Affecting Haul-Out Behavior of Harbor Seals (Phoca vitulina) in Tidewater Glacier Inlets in Alaska: Can Tourism Vessels and Seals Coexist?

Science.gov (United States)

Blundell, Gail M; Pendleton, Grey W

2015-01-01

Large numbers of harbor seals (Phoca vitulina) use habitat in tidewater glaciers in Alaska for pupping, breeding, and molting. Glacial fjords are also popular tourist destinations; however, visitation by numerous vessels can result in disturbance of seals during critical life-history phases. We explored factors affecting haul-out behavior of harbor seals at a glacial site frequented by tourism vessels. In 2008-10, we deployed VHF transmitters on 107 seals in Endicott Arm, Alaska. We remotely monitored presence and haul-out behavior of tagged seals and documented vessel presence with time-lapse cameras. We evaluated the influence of environmental and physical factors on the probability of being hauled out, duration of haul-out bouts, and as factors associated with the start and end of a haulout. Location, season, hour, and interactions of location by year, season, hour, and sex significantly influenced haul-out probability, as did ice, weather, and vessels. Seals were more likely to be hauled out with greater ice availability during the middle of the day, and less likely to be hauled out if vessels were present. Cruise ships had the strongest negative effect; however, most vessel types negatively affected haul-out probability. Haul-out duration was longest in association with starting on incoming tides, clear skies, no precipitation, occurring in the middle of the day, and ending in the late afternoon or evening. End of haulouts was associated with increasing cloud cover, low ice availability, and vessel presence; large-sized tourism vessels or all-vessel-types combined were significant predictors of ending a haul-out bout. Probability of being hauled out was highest in June, during pupping season. Potential disturbances of harbor seals could be reduced, enabling longer resting times for seals and fewer interruptions for nursing pups, if vessels focused the majority of visits to glacial habitat to before or after the hours of 08:00-17:00 or, less optimally, 09:00-16:00.

Flexible ring seal

International Nuclear Information System (INIS)

Abbes, Claude; Gournier, Andre; Rouaud, Christian; Villepoix, Raymond de.

1976-01-01

The invention concerns a flexible metal ring seal, able to ensure a perfect seal between two bearings due to the crushing and elastic deformation properties akin to similar properties in elastomers. Various designs of seal of this kind are already known, particularly a seal made of a core formed by a helical wire spring with close-wound turns and with high axial compression ratio, closed on itself and having the shape of an annulus. This wire ring is surrounded by at least one envelope having at rest the shape of a toroidal surface of which the generating circle does not close on itself. In a particular design mode, the seal in question can include, around the internal spring, two envelopes of which one in contact with the spring is composed of a low ductility elastic metal, such as mild steel or stainless steel and the other is, on the contrary, made of a malleable metal, such as copper or nickel. The first envelope evenly distributes the partial crushing of the spring, when the seal is tightened, on the second envelope which closely fits the two surfaces between which the seal operates. The stress-crushing curve characteristic of the seal comprises two separate parts, the first with a relatively sharp slope corresponds to the start of the seal compression phase, enabling at least some of these curves to reach the requisite seal threshold very quickly, then, beyond this, a second part, practically flat, where the stress is appreciably constant for a wide operating bracket [fr

Active Infrared Thermography for Seal Contamination Detection in Heat-Sealed Food Packaging

Directory of Open Access Journals (Sweden)

Karlien D’huys

2016-11-01

Full Text Available Packaging protects food products from environmental influences, assuring quality and safety throughout shelf life if properly performed. Packaging quality depends on the quality of the packaging material and of the closure or seal. A common problem possibly jeopardizing seal quality is the presence of seal contamination, which can cause a decreased seal strength, an increased packaging failure risk and leak formation. Therefore, early detection and removal of seal contaminated packages from the production chain is crucial. In this work, a pulsed-type active thermography method using the heated seal bars as an excitation source was studied for detecting seal contamination. Thermal image sequences of contaminated seals were recorded shortly after sealing. The detection performances of six thermal image processing methods, based on a single frame, a fit of the cooling profiles, thermal signal reconstruction, pulsed phase thermography, principal component thermography and a matched filter, were compared. High resolution digital images served as a reference to quantify seal contamination, and processed thermal images were mapped to these references. The lowest detection limit (equivalent diameter 0.60 mm was obtained for the method based on a fit of the cooling profiles. Moreover, the detection performance of this method did not depend strongly on the time after sealing at which recording of the thermal images was started, making it a robust and generally applicable method.

Nuclear reactor sealing system

International Nuclear Information System (INIS)

McEdwards, J.A.

1983-01-01

A liquid metal-cooled nuclear reactor sealing system is disclosed. The nuclear reactor includes a vessel sealed at its upper end by a closure head. The closure head comprises at least two components, one of which is rotatable; and the two components define an annulus therebetween. The sealing system includes at least a first and second inflatable seal disposed in series in an upper portion of the annulus. The system further includes a dip seal extending into a body of insulation located adjacent a bottom portion of the closure head. The dip seal comprises a trough formed by a lower portion of one of the components, and a seal blade pendently supported from the other component and extending downwardly into the trough. A body of liquid metal is contained in the trough which submerges a portion of the seal blade. The seal blade is provided with at least one aperture located above the body of liquid metal for providing fluid communication between the annulus intermediate the dip seal and the inflatable seals, and a body of cover gas located inside the vessel. There also is provided means for introducing a purge gas into the annulus intermediate the inflatable seals and the seal blade. The purge gas is introduced in an amount sufficient to substantially reduce diffusion of radioactive cover gas or sodium vapor up to the inflatable seals. The purge gas mixes with the cover gas in the reactor vessel where it can be withdrawn from the vessel for treatment and recycle to the vessel

The IRES electronic seal

International Nuclear Information System (INIS)

Autrusson, B.; Brochard, D.; Moreau, J.F.; Martin, J.C.

2001-01-01

In the framework of the French Support Program for the IAEA Safeguards, the 'Institut de Protection et de Surete Nucleaire' (IPSN), developed an electronic seal called Integrated and Reusable Electronic Seal (IRES) that enables independent verification by different inspectorates (IAEA, Euratom, and National Inspectorate). The seal can be remotely interrogated by radio frequency and integrated to other Containment/surveillance systems by serial line RS 485. Data are authenticated and the IRESMAG software manages in the seal reader all functionalities of the seal and records inspection data compatible with the IAEA's Seal Database. To perform this development, IPSN relies on industrial partners: SAPHYMO for the general architecture of the seal and the electronics, THALES for the authentication of data and the security of transmission. The main features of the IRES seal are the following: Interrogation by different inspectorate, allowing independent conclusions; Recording of events, including tampering, in a non-volatile memory; Authentication of data and enhanced security of the communication between the seal and the seal reader; Remote interrogation by an inspector or/and automatic for unattended systems or remote monitoring; Reusable after erasing the seal memory and replacement of the batteries

Compliant seal development

Science.gov (United States)

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.

Self-acting shaft seals

Science.gov (United States)

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.

HMSRP Hawaiian Monk Seal Master Identification Records (seal)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains records of all individually identified Hawaiian monk seals since 1981. These seals were identified by PSD personnel and cooperating scientists...

Sealing devices

International Nuclear Information System (INIS)

Coulson, R.A.

1980-01-01

A sealing device for minimising the leakage of toxic or radioactive contaminated environments through a biological shield along an opening through which a flexible component moves that penetrates the shield. The sealing device comprises an outer tubular member which extends over a length not less than the maximum longitudinal movement of the component along the opening. An inner sealing block is located intermediate the length of the component by connectors and is positioned in the bore of the outer tubular member to slide in the bore and effect a seal over the entire longitudinal movement of the component. The cross-section of the device may be circular and the block may be of polytetrafluoroethylene or of nylon impregnated with molybdenum or may be metallic. A number of the sealing devices may be combined into an assembly for a plurality of adjacent longitudinally movable components, each adapted to sustain a tensile load, providing the various drives of a master-slave manipulator. (author)

Hermetically Sealed Compressor

Science.gov (United States)

Holtzapple, Mark T.

1994-01-01

Proposed hermetically sealed pump compresses fluid to pressure up to 4,000 atm (400 MPa). Pump employs linear electric motor instead of rotary motor to avoid need for leakage-prone rotary seals. In addition, linear-motor-powered pump would not require packings to seal its piston. Concept thus eliminates major cause of friction and wear. Pump is double-ended diaphragm-type compressor. All moving parts sealed within compressor housing.

Diving into old age: muscular senescence in a large-bodied, long-lived mammal, the Weddell seal (Leptonychotes weddellii).

Science.gov (United States)

Hindle, Allyson G; Horning, Markus; Mellish, Jo-Ann E; Lawler, John M

2009-03-01

Classic aging theory postulates the absence of pronounced organismal senescence in wild animals since mortality probably occurs first. Large-bodied, long-lived mammals are a recognized exception to this tenet, yet organismal senescence has not been investigated to date in such mammals in the wild. Furthermore, oxidative stress theory of aging supports the suggestion that exercise hypoxia, as regularly incurred during apneustic foraging in diving mammals might lead to cellular dysfunction and accelerated aging. To determine if an aspect of organismal senescence occurs in wild marine mammals, we examined the pattern of skeletal muscle aging (contractile and connective tissue components of longissimus dorsi and pectoralis muscles) in free-ranging adult Weddell seals (9-26 years). The average myocyte cross-sectional area was 22% greater with age in the longissiums dorsi, but no significant increase occurred in the pectoralis. Cross-sectional area was not related to body mass. Changes in myocyte number per area were consistent with the 35-40% age-increase in extracellular space in both muscle groups. Also consistent with extracellular space remodeling, total and relative collagen contents were significantly elevated in older seals (115% in longissimus dorsi; 65% in pectoralis). The ratio of muscle myocyte to collagen declined with age (50-63%) at both sites. Additionally, a shift towards a higher ratio of type I to type III collagen occurred with advancing age in both muscle groups (79% increase in pectoralis; 49% in longissimus dorsi). We reject the classic tenet and null-hypothesis that Weddell seals do not survive to an age where muscular senescence becomes detectable.

Long-term sealing of openings in salt formations

International Nuclear Information System (INIS)

Walter, F.; Stockmann, N.; Yaramanci, U.; Laurens, J.F.

1993-01-01

Radioactive wastes can be disposed of in deep salt formations. Rock salt is a suitable geologic medium because of its unique characteristics. Open boreholes, shafts and drifts are created to provide physical access to the repository. Long-term seals must be emplaced in those potential pathways to prevent radioactive release to the biosphere. The sealing materials must be mechanically and, most important, geochemically stable within the host rock. Salt bricks made of compressed salt-powder are understood to be the first choice long-term sealing material. Seals built from salt bricks will be ductile. The permeability of the salt bricks is assumed to be in the order of 2*10 -15 m 2 . Large sealing systems are built by combining the individual bricks with mortar. Raw materials for mortar are fine-grained halite powder and ground saliferous clay. The permeability of the mortar decreases with its salt content to approx. 2*10 -14 m 2 . Moistened saliferous clay may show temporary swelling. Sealing experiments will be carried out in the Asse salt mine. Long-term seals will be built into holes of 1 m diameter. The contact and merging of the brick-wall with the surrounding rock salt will be investigated in long-term tests. Within the in situ sealing program a number of geophysical methods are applied. Acoustic emission measurements are used to study the effects of high pressure gas injection and a geoelectrical observation program is aiming to estimate the permeability in and around the long-term seal. High frequency electromagnetic methods contribute to the knowledge of the petrophysical rock properties. 11 refs., 12 figs

Reinforced seal component

International Nuclear Information System (INIS)

Jeanson, G.M.; Odent, R.P.

1980-01-01

The invention concerns a seal component of the kind comprising a soft sheath and a flexible reinforcement housed throughout the entire length of the sheath. The invention enables O ring seals to be made capable of providing a radial seal, that is to say between two sides or flat collars of two cylindrical mechanical parts, or an axial seal, that is to say between two co-axial axisymmetrical areas. The seal so ensured is relative, but it remains adequately sufficient for many uses, for instance, to ensure the separation of two successive fixed blading compartments of axial compressors used in gas diffusion isotope concentration facilities [fr

Numerical Investigation of the Effect of Radial Lip Seal Geometry on Sealing Performance

Science.gov (United States)

Tok, G.; Parlar, Z.; Temiz, V.

2018-01-01

Sealing elements are often needed in industry and especially in machine design. With the change and development of machine technology from day to day, sealing elements show continuous development and change in parallel with these developments. Many factors influence the performance of the sealing elements such as shaft surface roughness, radial force, lip geometry etc. In addition, the radial lip seals must have a certain pre-load and interference in order to provide a good sealing. This also affects the friction torque. Researchers are developing new seal designs to reduce friction losses in mechanical systems. In the presented study, the effect of the lip seal geometry on sealing performance will be examined numerically. The numerical model created for this purpose will be verified with experimental data firstly. In the numerical model, shaft and seal will be modeled as hyper-elastic in 2D and 3D. NBR (Nitrile Butadiene Rubber) as seal material will be analyzed for the rotating shaft state at constant speed by applying a uniform radial force.

Reactor vessel sealing plug

International Nuclear Information System (INIS)

Dooley, R.A.

1986-01-01

This invention relates to an apparatus and method for sealing the cold leg nozzles of a nuclear reactor pressure vessel from a remote location during maintenance and inspection of associated steam generators and pumps while the pressure vessel and refueling canal are filled with water. The apparatus includes a sealing plug for mechanically sealing the cold leg nozzle from the inside of a reactor pressure vessel. The sealing plugs include a primary and a secondary O-ring. An installation tool is suspended within the reactor vessel and carries the sealing plug. The tool telescopes to insert the sealing plug within the cold leg nozzle, and to subsequently remove the plug. Hydraulic means are used to activate the sealing plug, and support means serve to suspend the installation tool within the reactor vessel during installation and removal of the sealing plug

High pressure shaft seal

International Nuclear Information System (INIS)

Martinson, A.R.; Rogers, V.D.

1980-01-01

In relation to reactor primary coolant pumps, mechanical seal assembly for a pump shaft is disclosed which features a rotating seal ring mounting system which utilizes a rigid support ring loaded through narrow annular projections in combination with centering non-sealing O-rings which effectively isolate the rotating seal ring from temperature and pressure transients while securely positioning the ring to adjacent parts. A stationary seal ring mounting configuration allows the stationary seal ring freedom of motion to follow shaft axial movement up to 3/4 of an inch and shaft tilt about the pump axis without any change in the hydraulic or pressure loading on the stationary seal ring or its carrier. (author)

Does the seal licensing system in Scotland have a negative impact on seal welfare?

Directory of Open Access Journals (Sweden)

Laetitia Nunny

2016-08-01

Full Text Available This study examined the licensing system that permits seal shooting in Scotland, which was established under Part 6 Conservation of Seals of the Marine (Scotland Act 2010. Four approaches were used: data were collated and analyzed from both the Scottish Government and Scottish Marine Animal Stranding Scheme; a survey was sent to current license holders and informal interviews were conducted with key stakeholder types. Between February 2011 and the end of October 2015, 1229 gray seals and 275 common seals were reported shot under license to the Scottish Government. The numbers of seals reported as shot has reduced year-on-year since the licensing system was put in place. While some license holders, notably fish farms, were using some non-lethal forms of deterrent to reduce seal-related damage, these were often used alongside seal shooting. Of the seals reported as shot to the Scottish Government, only a small percentage were also reported to the Scottish Marine Animal Stranding Scheme, despite this being a licensing requirement. Only 2.3% of the shot gray seals and 4.5% of the shot common seals were necropsied. There is evidence from these necropsies that some seals had not died instantly or had not been shot in the manner recommended by the Scottish Seal Management Code of Practice. These preliminary results show that more carcasses need to be recovered and necropsied if the welfare implications of current seal shooting practice are to be properly assessed. The current legislation does not specify closed seasons to protect breeding seals and thirty-five per cent of necropsied seals were pregnant gray seals. Seals have also been shot during their lactation periods when pups are dependent on their mothers. This raises significant welfare concerns. The re-introduction of closed seasons specific to each species of seal is recommended along with greater effort to deploy non-lethal methods. Independent assessment of the number of seals being killed

SSME Seal Test Program: Test results for sawtooth pattern damper seal

Science.gov (United States)

Childs, D. W.

1986-01-01

Direct and transverse force coefficients for 11, sawtooth-pattern, and damper-seal configurations were examined. The designation damper seal uses a deliberately roughened stator and smooth rotor to increase the net damping force developed by a seal. The designation sawtooth-pattern refers to a stator roughness pattern. The sawtooth pattern yields axial grooves in the stator which are interrupted by spacer elements which act as flow constrictions or dams. All seals use the same smooth rotor and have the same, constant, minimum clearance. The stators examined the consequences of changes in the following design parameters: (1) axial-groove depth; (2) number of teeth: (3) number of sawtooth sections; (4) number of spacer elements; (5) dam width; (6) axially aligned sawtooth sections versus axially-staggered sawtooth sections; and (7) groove geometry. It is found that none of the sawtooth-pattern seal performs as well as the best round-hole-pattern seal. Maximum damping configurations for the sawtooth and round-hole-pattern stators have comparable stiffness performance. Several of the sawtooth pattern stators outperformed the best round-hole pattern seal.

Circumferential shaft seal

Science.gov (United States)

Ludwig, L. P. (Inventor)

1981-01-01

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

Sealing arrangement for radioactive material

International Nuclear Information System (INIS)

Gray, I.L.S.; Sievwright, R.W.T.; Elliott, J.C.

1993-01-01

A sealing arrangement for hermetically sealing two mating surfaces comprises two seals arranged to lie between the surfaces. Each seal provides hermetic sealing over a respective different temperature range and lie serially along the surfaces between the regions to be isolated. A main seal integrity test arrangement is provided in the form of a port and passage. This allows for the introduction of a fluid into or the evacuation of a region between the two seals to detect a leak. The port is also provided with at least two test port seals which seal with a plug. The plug is also provided with a test port to allow the integrity of the test port seal to be tested. (UK)

Severe service sealing solutions

International Nuclear Information System (INIS)

Metcalfe, R.; Wensel, R.

1994-09-01

Successful sealing usually requires much more than initial leak-tightness. Friction and wear must also be acceptable, requiring a good understanding of tribology at the sealing interface. This paper describes various sealing solutions for severe service conditions. The CAN2A and CAN8 rotary face seals use tungsten carbide against carbon-graphite to achieve low leakage and long lifetime in nuclear main coolant pumps. The smaller CAN6 seal successfully uses tungsten carbide against silicon carbide in reactor water cleanup pump service. Where friction in CANDU fuelling machine rams must be essentially zero, a hydrostatic seal using two silicon carbide faces is the solution. In the NRU reactor moderator pumps, where pressure is much lower, eccentric seals that prevent boiling at the seal faces are giving excellent service. All these rotary face seals rely on supplementary elastomer seals between their parts. An integrated engineering approach to high performance sealing with O-rings is described. This is epitomized in critical Space Shuttle applications, but is increasingly being applied in CANDU plants. It includes gland design, selection and qualification of material, quality assurance, detection of defects and the effects of lubrication, surface finish, squeeze, stretch and volume constraints. In conclusion, for the severe service applications described, customized solutions have more than paid for themselves by higher reliability, lower maintenance requirements and reduced outage time. (author)

Research on seal control systems for international nuclear safeguard and the vulnerability assessment on the seals

International Nuclear Information System (INIS)

Zhang Hongjian; Liu Tianshu; Cao Fangfang; Xu Chunyan

2014-01-01

Safeguard seals, also called Tamper-indicating devices (TIDs), are widely used to detect tampering or unauthorized entry in the international safeguard and security systems, Seal control systems consist of seal implementing plan, seal development and the vulnerability assessment on tbe seals, effective implementing procedures and methods of the seals. The vulnerability assessment contents of safeguard seals, thermo-shrinked film seals being as an example, and seals control systems in the implementation program are researched. The seal control systems discuss task assignment, seals management flow and seals program data flow to promote applying effectively seals. The vulnerability assessment program of seals studies assurance level to some different tampering techniques and measures. The researches must promote utilizing seals effectively for nuclear security, non-proliferation of nuclear weapons, radioactive waste management, and the nuclear material accounting and control. (authors)

Global environmental controls of diversity in large herbivores

NARCIS (Netherlands)

Olff, Han; Ritchie, Mark E.; Prins, Herbert H.T.

2002-01-01

Large mammalian herbivores occupy half of the earth's land surface and are important both ecologically and economically, but their diversity is threatened by human activities. We investigated how the diversity of large herbivores changes across gradients of global precipitation and soil fertility.

The IRES electronic seal

International Nuclear Information System (INIS)

Gourlez, P.; Funk, P.; Brochard, D.; Moreau, J.F.; Martin, J.C.

2001-01-01

In the framework of the French Support Program for the IAEA Safeguards, the 'Institut de Protection et de Surete Nucleaire' (IPSN), developed an electronic seal called Integrated and Reusable Electronic Seal (IRES) that enables independent verification by different inspectorates (IAEA, Euratom, and National Inspectorate) Furthermore, a bilateral co-ordination between Euratom and French domestic safeguards takes place in some French facilities regarding a common approach concerning the seals especially in case of crisis situation. The seal can be remotely interrogated by radio frequency and integrated to other Containment/surveillance systems by serial line RS 485. Data are authenticated and the IRESMAG software manages in the seal reader all functionalities of the seal and records inspection data compatible with the IAEA's Seal Database

Cover-gas-seal component development: dynamic inflatable-plug seal improvement

International Nuclear Information System (INIS)

Horton, P.H.

1977-01-01

This report documents the 1) radial compliance and 2) low friction coating tests conducted on the CRBRP Rotating Plug Inflatable Seals per test plan N707TR810014. Test results show that narrowing the seal blade from 0.25 to 0.12 in. will effectively reduce dynamic drag from 30 to 20 lb/ft under nominal conditions and will increase seal radial compliance from 0.12 to 0.30 in. without an unacceptable rise in dynamic drag. Tests also demonstrated that application of a teflon coating to the seal wear surface reduced breakaway drag by 25% based on results of comparison dwells

Effect of bar sealing parameters on OPP/MCPP heat seal strength

Directory of Open Access Journals (Sweden)

2007-11-01

Full Text Available The effect of bar sealing parameters on the heat seal strength of oriented polypropylene (OPP/metallic cast polypropylene (MCPP laminate film was investigated. Based on the results obtained from the parametric study, a bar sealing process window was developed. All points drop within the process window are combinations of platen temperature and dwell time that produce acceptable heat seal. Optimum combinations are indicated by the lower border of the window. The plateau initiation temperature, Tpi of OPP/MCPP laminate film used in the present study occurred before the final melting temperature, Tmf of the sealant material. The highest achievable heat seal strength was at the plateau region, and the corresponding failure modes were delaminating, tearing or combine failure modes (delaminating and tearing. Minimum pressure level of 1.25 bars is necessary to bring the laminate interface into intimate contact in order to effect sealing.

Comparative study on two different seal surface structure for reactor pressure vessel sealing behavior

International Nuclear Information System (INIS)

Chen Jun; Xiong Guangming; Deng Xiaoyun

2014-01-01

The seal surface structure is very important to reactor pressure vessel (RPV) sealing behavior. In this paper, two 3-D RPV sealing analysis finite models have been established with different seal surface structures, in order to study the influence of two structures. The separation of RPV upper and lower flanges, bolt loads and etc. are obtained, which are used to evaluate the sealing behavior of the RPV. Meanwhile, the comparative analysis of safety margin of two seal surface structural had been done, which provides the theoretical basis for RPV seal structure design optimization. (authors)

Clawed forelimbs allow northern seals to eat like their ancient ancestors

Science.gov (United States)

Hocking, David P.; Marx, Felix G.; Sattler, Renae; Harris, Robert N.; Pollock, Tahlia I.; Sorrell, Karina J.; Fitzgerald, Erich M. G.; McCurry, Matthew R.; Evans, Alistair R.

2018-04-01

Streamlined flippers are often considered the defining feature of seals and sea lions, whose very name `pinniped' comes from the Latin pinna and pedis, meaning `fin-footed'. Yet not all pinniped limbs are alike. Whereas otariids (fur seals and sea lions) possess stiff streamlined forelimb flippers, phocine seals (northern true seals) have retained a webbed yet mobile paw bearing sharp claws. Here, we show that captive and wild phocines routinely use these claws to secure prey during processing, enabling seals to tear large fish by stretching them between their teeth and forelimbs. `Hold and tear' processing relies on the primitive forelimb anatomy displayed by phocines, which is also found in the early fossil pinniped Enaliarctos. Phocine forelimb anatomy and behaviour therefore provide a glimpse into how the earliest seals likely fed, and indicate what behaviours may have assisted pinnipeds along their journey from terrestrial to aquatic feeding.

Seals in motion

NARCIS (Netherlands)

Brasseur, Sophie Marie Jacqueline Michelle

2017-01-01

The harbour seal Phoca vitulina and the grey seal Halichoerus grypus have been inhabitants of the Wadden Sea since millennia. Prehistoric findings indicate the presence of both species around 5000 BC. This changed dramatically in the mid Middle-Ages as around 1500 AC, the grey seal disappeared from

Automated Image Acquisition System for the Verification of Copper-Brass Seal Images

International Nuclear Information System (INIS)

Stringa, E.; Bergonzi, C.; Littmann, F.; ); Marszalek, Y.; Tempesta, S.; )

2015-01-01

This paper describes a system for the verification of copper-brass seals realized by JRC according to DG ENER requirements. DG ENER processes about 20,000 metal seals per year. The verification of metal seals consists in visually checking the identity of a removed seal. The identity of a copper-brass seal is defined by a random stain pattern realized by the seal producer together with random scratches engraved when the seals are initialized ('seal production'). In order to verify that the seal returned from the field is the expected one its pattern is compared with an image taken during seal production. Formerly, seal initialization and verification were very heavy tasks as seal pictures were acquired with a camera one by one both in the initialization and verification stages. During the initialization the Nuclear Safeguards technicians had to place one by one new seals under a camera and acquire the related reference images. During the verification, the technician had to take used seals and place them one by one under a camera to take new pictures. The new images were presented to the technicians without any preprocessing and the technicians had to recognize the seal. The new station described in this paper has an automated image acquisition system allowing to easily process seals in batches of 100 seals. To simplify the verification, a software automatically centres and rotates the newly acquired seal image in order to perfectly overlap with the reference image acquired during the production phase. The new system significantly speeds up seal production and helps particularly with the demanding task of seal verification. As a large part of the seals is dealt with by a joint Euratom-IAEA team, the IAEA directly profits from this development. The new tool has been in routine use since mid 2013. (author)

Design and development of face seal type sealing plug for advanced heavy water reactor

International Nuclear Information System (INIS)

Bansal, S.; Bhattacharyya, S.; Patel, R.J.; Agrawal, R.G.; Vaze, K.K.

2005-09-01

Advanced Heavy Water Reactor is a vertical pressure tube type reactor having light water as its coolant and heavy water as moderator. Sealing plug is required to close the pressure boundary of main heat transport system of the reactor by preventing escape of light water/steam From the coolant channel. There are 452 coolant channels in the reactor located in square lattice pitch. Sealing plug is located at the top of each coolant channel (in the top end fitting). Top end fitting is having a stepped bore to create a sealing face. Sealing plug is held through its expanded jaws in a specially provided groove of the end fitting. The plug was designed and prototypes were manufactured considering its functional importance, intricate design and precision machining requirements. Sealing plug consists of about 20 components mostly made up of precipitation hardening stainless steel, which is suitable for water environment and meets other requirements of strength and resistance to wear and galling. Seal disc is a critical component of the sealing plug as it is the pressure-retaining component. It is a circular disc with protruded stem. One face of the seal disc is nickel plated in the peripheral area that creates the sealing by abutting against the sealing face provided in the end fitting. The typical shape and profile of seal disc provides flexibility and allows elastic deformation to assist in locking of sealing plug and creating adequate seating force for effective sealing. Design and development aspects of the sealing plug have been detailed out in this report. Also results of stress analysis and experimental studies for seal disc have been mentioned in the report. Stress analysis and experimental testing was required for the seal disc because high stresses are developed due to its exposure to high pressure and temperature environment of Main Heat Transport system. Hot testing was carried out to simulate the reactor-simulated condition. The performance was found to be

Cover gas seals. 11 - FFTF-LMFBR seal-test program, January-March 1974

International Nuclear Information System (INIS)

Kurzeka, W.; Oliva, R.; Welch, F.

1974-01-01

The objectives of this program are to: (1) conduct static and dynamic tests to demonstrate or determine the mechanical performance of full-size (cross section) FFTF fuel transfer machine and reactor vessel head seals intended for use in a sodium vapor - inert gas environment, (2) demonstrate that these FFTF seals or new seal configuration provide acceptable fission product and cover gas retention capabilities at LMFBR Clinch River Plant operating environmental conditions other than radiation, and (3) develop improved seals and seal technology for the LMFBR Clinch River Plant to support the national objective to reduce all atmospheric contaminations to low levels

Upgrading elastomer seals for nuclear service

Energy Technology Data Exchange (ETDEWEB)

Wittich, K C; Wensel, R; LaRose, R; Kuran, S

1995-06-01

Pumps, valves and instruments in nuclear plants have historically contained whatever elastomer each equipment supplier traditionally used for corresponding non-nuclear service. The proliferation of elastomer compounds, and their sometimes uncertain reliability, is now being reduced by upgrading and standardizing on a handful of compounds that have each been verified to be high performers for their class of service conditions. The objective is to make cost-effective improvements in the reliability and integrity of equipment in Canadian-designed nuclear plants. The effort focuses on elastomer seals and includes: understanding sealing fundamentals, developing relevant data for superior compounds for each service, and improving quality assurance methods, including handling and inspection guidelines. In practice, discussions with plant personnel and review of plant records are the first step. Two severe-service examples are given where these needs have been met by the following progression of activities: inspecting and laboratory testing of seals removed from service, preliminary and qualification testing of improvements, introduction into service, and monitoring the upgraded seals during phase-in periods. Large gains in reliability and integrity have been demonstrated for simulated normal and accident service conditions of heat, radiation and other deteriorative influences. Significant savings in maintenance costs are also projected. (author). 2 refs., 6 figs.

Upgrading elastomer seals for nuclear service

International Nuclear Information System (INIS)

Wittich, K.C.; Wensel, R.; LaRose, R.; Kuran, S.

1995-06-01

Pumps, valves and instruments in nuclear plants have historically contained whatever elastomer each equipment supplier traditionally used for corresponding non-nuclear service. The proliferation of elastomer compounds, and their sometimes uncertain reliability, is now being reduced by upgrading and standardizing on a handful of compounds that have each been verified to be high performers for their class of service conditions. The objective is to make cost-effective improvements in the reliability and integrity of equipment in Canadian-designed nuclear plants. The effort focuses on elastomer seals and includes: understanding sealing fundamentals, developing relevant data for superior compounds for each service, and improving quality assurance methods, including handling and inspection guidelines. In practice, discussions with plant personnel and review of plant records are the first step. Two severe-service examples are given where these needs have been met by the following progression of activities: inspecting and laboratory testing of seals removed from service, preliminary and qualification testing of improvements, introduction into service, and monitoring the upgraded seals during phase-in periods. Large gains in reliability and integrity have been demonstrated for simulated normal and accident service conditions of heat, radiation and other deteriorative influences. Significant savings in maintenance costs are also projected. (author). 2 refs., 6 figs

Upgrading elastomer seals for nuclear service

International Nuclear Information System (INIS)

Wittich, K.C.; Wensel, R.; Larose, R.; Kuran, S.

1998-01-01

Pumps, valves and instruments in nuclear plants have historically contained whatever elastomer each equipment supplier traditionally used for corresponding non-nuclear service. The proliferation of elastomer compounds, and their sometimes uncertain reliability, is now being reduced by upgrading and standardizing on a handful of compounds that have each been verified to be high performers for their class of service conditions. The objective is to make cost-effective improvements in the reliability and integrity of equipment in Canadian-designed nuclear plants. The effort focuses on elastomer seals and includes: understanding sealing fundamentals, developing relevant data for superior compounds for each service, and improving quality assurance methods, including handling and inspection guidelines. In practice, discussion with plant personnel and review of plant records are the first step. Two severe-service examples are given where these needs have been met by the following progression of activities: inspecting and laboratory testing of seals removed from service, preliminary and qualification testing of improvements, introduction into service, and monitoring the upgraded seals during phase-in periods. Large gains in reliability and integrity have been demonstrated for simulated normal and accident service conditions of heat, radiation and other deteriorative influences. Significant savings in maintenance costs are also projected. (author)

Seals Research at AlliedSignal

Science.gov (United States)

Ullah, M. Rifat

1996-01-01

A consortium has been formed to address seal problems in the Aerospace sector of Allied Signal, Inc. The consortium is represented by makers of Propulsion Engines, Auxiliary Power Units, Gas Turbine Starters, etc. The goal is to improve Face Seal reliability, since Face Seals have become reliability drivers in many of our product lines. Several research programs are being implemented simultaneously this year. They include: Face Seal Modeling and Analysis Methodology; Oil Cooling of Seals; Seal Tracking Dynamics; Coking Formation & Prevention; and Seal Reliability Methods.

Brush seal performance measurement system

OpenAIRE

Aksoy, Serdar; Akşit, Mahmut Faruk; Aksit, Mahmut Faruk; Duran, Ertuğrul Tolga; Duran, Ertugrul Tolga

2009-01-01

Brush seals are rapidly replacing conventional labyrinth seals in turbomachinery applications. Upon pressure application, seal stiffness increases drastically due to frictional bristle interlocking. Operating stiffness is critical to determine seal wear life. Typically, seal stiffness is measured by pressing a curved shoe to brush bore. The static-unpressurized measurement is extrapolated to pressurized and high speed operating conditions. This work presents a seal stiffness measurement syste...

Seals

International Nuclear Information System (INIS)

Welsher, R.A.G.

1982-01-01

An aperture through a biological shield is sealed by a flexible sheath having a beading at one end located on an annular member slidable in the aperture such that the beading bears in sealing engagement against the sides of the aperture. The annular member is retained by a retractable latch and can be rejected by pushing it out of the aperture using a replacement annular member with a replacement sheath thereon to butt against the annular member to be rejected. The replacement annular member may be mounted on a tubular device having an outer co-axial member for operating the latch when the replacement annular member butts against the annular member to be rejected. Applications include effecting a seal between a remote handling equipment and a wall through which the equipment extends. (author)

Electronic seal

International Nuclear Information System (INIS)

Musyck, E.

1981-01-01

An electronic seal is presented for a volume such as container for fissile materials. The seal encloses a lock for barring the space as well as a device for the detection and the recording of the intervention of the lock. (AF)

Globally sourced mineral commodities used in U.S. Navy SEAL gear—An illustration of U.S. net import reliance

Science.gov (United States)

Brainard, Jamie; Nassar, Nedal T.; Gambogi, Joseph; Baker, Michael S.; Jarvis, Michael T.

2018-01-25

A U.S. Navy SEAL (an acronym for sea, air, land) carries gear containing at least 23 nonfuel mineral commodities for which the United States is greater than 50 percent net import reliant. The graphics display the leading world producers of selected nonfuel mineral commodities used to manufacture U.S. Navy SEAL gear. SEALs are members of the U.S. Navy's special operations forces.

How to simulate global cosmic strings with large string tension

Energy Technology Data Exchange (ETDEWEB)

Klaer, Vincent B.; Moore, Guy D., E-mail: vklaer@theorie.ikp.physik.tu-darmstadt.de, E-mail: guy.moore@physik.tu-darmstadt.de [Institut für Kernphysik, Technische Universität Darmstadt, Schlossgartenstraße 2, Darmstadt, D-64289 Germany (Germany)

2017-10-01

Global string networks may be relevant in axion production in the early Universe, as well as other cosmological scenarios. Such networks contain a large hierarchy of scales between the string core scale and the Hubble scale, ln( f {sub a} / H ) ∼ 70, which influences the network dynamics by giving the strings large tensions T ≅ π f {sub a} {sup 2} ln( f {sub a} / H ). We present a new numerical approach to simulate such global string networks, capturing the tension without an exponentially large lattice.

A hybrid floating brush seal (HFBS) for improved sealing and wear performance in turbomachinery applications

Science.gov (United States)

Lattime, Scott Byran

A conceptually new type of seal has been developed for gas turbine applications which dramatically reduces wear and leakage associated with current labyrinth and brush seal technologies. The Hybrid Floating Brush Seal (HFBS) combines brush seal and film riding face seal technologies to create a hybrid seal that allows both axial and radial excursions of the sealed shaft, while simultaneously eliminating interface surface speeds (friction and heat) between the rotor and the brush material that characterize standard brush seal technology. A simple test rig was designed to evaluate feasibility of the HFBS under relatively low pressures and rotational speeds (50psig, 5krpm). A second test stand was created to study the effects of centrifugal force on bristle deflection. A third test facility was constructed for prototype development and extensive room temperature testing at moderate pressures and fairly high rotational speeds (100psig, 40krpm). This test rig also allowed the evaluation of the HFBS during axial movement of a rotating shaft. An analytical model to predict the effects of centrifugal force on the bristles of a rotating brush seal was developed. Room temperature analysis of the HFBS proved successful for relatively high operating rotational velocities at moderate pressures with very acceptable leakage rates for gas turbine engines. Brush seals were able to track rotor speeds up to 24krpm while maintaining sealing integrity. The HFBS's ability to function under axial shaft displacement and synchronous dynamic radial loading was also proven successful. Hydrodynamic performance of the face seal was proven to provide adequate stiffness and load carrying capacity to keep the brush seal from contacting the face seal at pressure drops across the brush of up to 100psi. Leakage performance over standard brush seal and labyrinth technology was quite dramatic. The HFBS showed its sealing advantage using much higher radial interference between the rotor and the bristle

Hydrodynamic perception in true seals (Phocidae) and eared seals (Otariidae).

Science.gov (United States)

Hanke, Wolf; Wieskotten, Sven; Marshall, Christopher; Dehnhardt, Guido

2013-06-01

Pinnipeds, that is true seals (Phocidae), eared seals (Otariidae), and walruses (Odobenidae), possess highly developed vibrissal systems for mechanoreception. They can use their vibrissae to detect and discriminate objects by direct touch. At least in Phocidae and Otariidae, the vibrissae can also be used to detect and analyse water movements. Here, we review what is known about this ability, known as hydrodynamic perception, in pinnipeds. Hydrodynamic perception in pinnipeds developed convergently to the hydrodynamic perception with the lateral line system in fish and the sensory hairs in crustaceans. So far two species of pinnipeds, the harbour seal (Phoca vitulina) representing the Phocidae and the California sea lion (Zalophus californianus) representing the Otariidae, have been studied for their ability to detect local water movements (dipole stimuli) and to follow hydrodynamic trails, that is the water movements left behind by objects that have passed by at an earlier point in time. Both species are highly sensitive to dipole stimuli and can follow hydrodynamic trails accurately. In the individuals tested, California sea lions were clearly more sensitive to dipole stimuli than harbour seals, and harbour seals showed a superior trail following ability as compared to California sea lions. Harbour seals have also been shown to derive additional information from hydrodynamic trails, such as motion direction, size and shape of the object that caused the trail (California sea lions have not yet been tested). The peculiar undulated shape of the harbour seals' vibrissae appears to play a crucial role in trail following, as it suppresses self-generated noise while the animal is swimming.

Experimental investigations of the geomechanical behaviour of plastic sealing sheets for sealing dumps. Final report; Experimentelle Untersuchungen zum geomechanischen Verhalten von Kunststoffdichtungsbahnen in Dichtungssystemen fuer Deponiebasisabdichtungen. Abschlussbericht

Energy Technology Data Exchange (ETDEWEB)

Schreyer, J; Wiesbaum, E

1991-12-01

Due to more severe environmental requirements, dumps have to be largely sealed to prevent harmful substances escaping into the environment and according to the state of technology, this is done by the combination of clay and plastic sealing tracks. Building on the knowledge from a completed research project `On the investigation of possibilities related to applications of a process for testing the mechanical behaviour of dump base seals made from sealing sheets`, the test processes described there were developed further and proposals were worked out for standardized execution of experiments. With the aid of a large number of experiments, minimum requirements were determined, which should serve to define the geo-mechanical properties of the plastic sealing sheets and to determine binding limits. (BBR). [Deutsch] Aufgrund schaerferer Umweltschutzauflagen muessen Deponien zur Verhinderung des Schadstoffaustritts in die Umwelt weitgehend abgedichtet werden, dem Stand der Technik entsprechend durch die Kombination von Tonen und Kunststoffdichtungsbahnen. Aufbauend auf den Erkenntnissen eines bereits abgeschlossenen Forschungsvorhabens `Zur Untersuchung der anwendungsbezogenen Moeglichkeiten eines Verfahrens zur Pruefung des mechanischen Verhaltens von Deponiebasisabdichtungen aus Dichtungsbahnen` wurden die dort beschriebenen Pruefverfahren fortentwickelt und Vorschlaege zur standardisierten Versuchsdurchfuehrung ausgearbeitet. Mit Hilfe einer groesseren Anzahl von Versuchen wurden Mindestanforderungen bestimmt, die dazu dienen sollen, geomechanische Eigenschaften der Kunststoffdichtungsbahnen zu definieren und verbindliche Grenzwerte festzulegen. (BBR).

Shaft seal assembly and method

Science.gov (United States)

Keba, John E. (Inventor)

2007-01-01

A pressure-actuated shaft seal assembly and associated method for controlling the flow of fluid adjacent a rotatable shaft are provided. The seal assembly includes one or more seal members that can be adjusted between open and closed positions, for example, according to the rotational speed of the shaft. For example, the seal member can be configured to be adjusted according to a radial pressure differential in a fluid that varies with the rotational speed of the shaft. In addition, in the closed position, each seal member can contact a rotatable member connected to the shaft to form a seal with the rotatable member and prevent fluid from flowing through the assembly. Thus, the seal can be closed at low speeds of operation and opened at high speeds of operation, thereby reducing the heat and wear in the seal assembly while maintaining a sufficient seal during all speeds of operation.

Rotary shaft seal

International Nuclear Information System (INIS)

Langebrake, C.O.

1984-01-01

The invention is a novel rotary shaft seal assembly which provides positive-contact sealing when the shaft is not rotated and which operates with its sealing surfaces separated by a film of compressed ambient gas whose width is independent of the speed of shaft rotation. In a preferred embodiment, the assembly includes a disc affixed to the shaft for rotation therewith. Axially movable, non-rotatable plates respectively supported by sealing bellows are positioned on either side of the disc to be in sealing engagement therewith. Each plate carries piezoelectric transducer elements which are electrically energized at startup to produce films of compressed ambient gas between the confronting surfaces of the plates and the disc. Following shutdown of the shaft, the transducer elements are de-energized. A control circuit responds to incipient rubbing between the plate and either disc by altering the electrical input to the transducer elements to eliminate rubbing

Seal containment system

International Nuclear Information System (INIS)

Kugler, R.W.; Gerkey, K.S.; Kasner, W.H.

1978-01-01

An automated system for transporting nuclear fuel elements between fuel element assembly stations without contaminating the area outside the sealed assembly stations is described. The system comprises a plurality of assembly stations connected together by an elongated horizontal sealing mechanism and an automatic transport mechanism for transporting a nuclear fuel element in a horizontal attitude between the assembly stations while the open end of the fuel element extends through the sealing mechanism into the assembly station enclosure. The sealing mechanism allows the fuel element to be advanced by the transport mechanism while limiting the escape of radioactive particles from within the assembly station enclosure. 4 claims, 6 figures

Compilation of current literature on seals, closures, and leakage for radioactive material packagings

International Nuclear Information System (INIS)

Warrant, M.M.; Ottinger, C.A.

1989-01-01

This report presents an overview of the features that affect the sealing capability of radioactive material packagings currently certified by the US Nuclear Regulatory Commission. The report is based on a review of current literature on seals, closures, and leakage for radioactive material packagings. Federal regulations that relate to the sealing capability of radioactive material packagings, as well as basic equations for leakage calculations and some of the available leakage test procedures are presented. The factors which affect the sealing capability of a closure, including the properties of the sealing surfaces, the gasket material, the closure method and the contents are discussed in qualitative terms. Information on the general properties of both elastomer and metal gasket materials and some specific designs are presented. A summary of the seal material, closure method, and leakage tests for currently certified packagings with large diameter seals is provided. 18 figs., 9 tabs

Core disruptive accident margin seal

International Nuclear Information System (INIS)

Golden, M.P.

1979-01-01

An apparatus for sealing the annulus defined within a substantially cylindrical rotatable riser assembly and plug combination of a nuclear reactor closure head is described. The apparatus comprises an inflatable sealing mechanism disposed in one portion of the riser assembly near the annulus such that upon inflation the sealing mechanism is radially actuated against the other portion of the riser assembly thereby sealing the annulus. The apparatus further comprises a connecting mechanism which places one end of the sealing mechanism in fluid communication with the reactor cover gas so that overpressurization of the reactor cover gas will increase the radial actuation of the sealing mechanism thus enhancing sealing of the annulus

Improved circumferential shaft seal

Science.gov (United States)

Ludwig, L. P.; Strom, T. N.

1974-01-01

Comparative tests of modified and unmodified carbon ring seals showed that addition of helical grooves to conventional segmented carbon ring seals reduced leakage significantly. Modified seal was insensitive to shaft runout and to flooding by lubricant.

Seals for sealing a pressure vessel such as a nuclear reactor vessel or the like

International Nuclear Information System (INIS)

Bruns, H.J.; Huelsermann, K.H.

1975-01-01

A description is given of seals for sealing a pressure vessel such as a nuclear reactor vessel, steam boiler vessel, or any other vessel which is desirably sealed against pressure of the type including a housing and a housing closure that present opposed vertical sealing surfaces which define the sides of a channel. The seals of the present invention comprise at least one sealing member disposed in the channel, having at least one stop face, a base portion and two shank portions extending from the base portion to form a groove-like recess. The shank portions are provided with sealing surfaces arranged to mate with the opposed vertical pressure vessel sealing surfaces. A shank-spreading wedge element also disposed in the channel has at least one stop face and is engaged in the groove-like recess with the sealing member and wedge element stop face adjacent to each other

Stationary spiraling eddies in presence of polar amplification of global warming as a governing factor of ecology of Greenland seals White Sea population: results of verification study

Science.gov (United States)

Melentyev, K.; Chernook, V.; Melentyev, V.

2003-04-01

Ice-associated forms of marine mammals are representatives of a high level of fodder chains in the ocean and taxation of population number for different group, as assessment of ecology and animal welfare are the important tasks for marine biology, ecology, fishery and other application uses. Many problems create a global warming and antropogenical impact on marine and coastal ecosystem. In order to investigate ice covered Arctic Ocean and charting the number of seals were performed annual inspections onboard research aircraft PINRO "Arktika". Multi-spectral airborne and satellite observations were fulfilled regularly from Barents and White Sea to the Bering and Okhotsk Sea (1996-2002). A contemporary status of different group of sea mammals was evaluated, where number of adults and pups were checked separately. In situ observations were provided with using helicopter and icebreaker for gathering a water samples and ice cores (with following biochemical and toxicological analysis). A prevailing part of life cycle of Greenland seals (harp seal) is strongly depended from winter hydrology (water masses, stable currents, meandering fronts, stationary eddies) and closely connected with type of ice (pack, fast ice) and other parameters of ice (age, origin, salinity, ice edge.). First-year ice floes which has a specific properties and distinctive features are used by harp seals for pupping, lactation, molting, pairing and resting. Ringed seals, inversely, use for corresponding purposes only fast-ice. Different aspects of ecology, and migration features of harp seals were analyzed in frame of verification study. It was revealed a scale of influence of winter severity and wind regime, but stationary eddies in the White Sea is most effective governing factor (novelty). Following relationship " eddies - ecology of Greenland seal White Sea population " will be discussed: A) regularities of eddies formation and their spatial arrangement, temporal (seasonal and annual

Oxygen minimum zone: An important oceanographic habitat for deep-diving northern elephant seals, Mirounga angustirostris.

Science.gov (United States)

Naito, Yasuhiko; Costa, Daniel P; Adachi, Taiki; Robinson, Patrick W; Peterson, Sarah H; Mitani, Yoko; Takahashi, Akinori

2017-08-01

Little is known about the foraging behavior of top predators in the deep mesopelagic ocean. Elephant seals dive to the deep biota-poor oxygen minimum zone (OMZ) (>800 m depth) despite high diving costs in terms of energy and time, but how they successfully forage in the OMZ remains largely unknown. Assessment of their feeding rate is the key to understanding their foraging behavior, but this has been challenging. Here, we assessed the feeding rate of 14 female northern elephant seals determined by jaw motion events (JME) and dive cycle time to examine how feeding rates varied with dive depth, particularly in the OMZ. We also obtained video footage from seal-mounted videos to understand their feeding in the OMZ. While the diel vertical migration pattern was apparent for most depths of the JME, some very deep dives, beyond the normal diel depth ranges, occurred episodically during daylight hours. The midmesopelagic zone was the main foraging zone for all seals. Larger seals tended to show smaller numbers of JME and lower feeding rates than smaller seals during migration, suggesting that larger seals tended to feed on larger prey to satisfy their metabolic needs. Larger seals also dived frequently to the deep OMZ, possibly because of a greater diving ability than smaller seals, suggesting their dependency on food in the deeper depth zones. Video observations showed that seals encountered the rarely reported ragfish ( Icosteus aenigmaticus ) in the depths of the OMZ, which failed to show an escape response from the seals, suggesting that low oxygen concentrations might reduce prey mobility. Less mobile prey in OMZ would enhance the efficiency of foraging in this zone, especially for large seals that can dive deeper and longer. We suggest that the OMZ plays an important role in structuring the mesopelagic ecosystem and for the survival and evolution of elephant seals.

NRC Information No. 90-23: Improper installation of Patel conduit seals

International Nuclear Information System (INIS)

Rossi, C.E.

1992-01-01

On November 6, 1989, the staff at the H.B. Robinson plant notified the NRC that they had discovered that some of the conduit seal grommets used to seal insulated wire conductors entering environmentally qualified instrument housings were oversized for the application. The seals are used to prevent moisture from entering safety-related electrical components following loss-of-coolant accidents. The problem was attributed to inadequate installation instructions that were used when the seals were installed in 1986 and 1987. These instructions listed the grommets by wire gauge size and gave maximum wire insulation diameters for each wire size. In accordance with these instructions, the seals were selected based on wire gauge alone. However, since the insulation thickness for a given wire gauge the correct grommet size would have been the minimum wire insulation diameter for which a particular grommet will achieve an effective seal. The selection of grommet size based only on wire gauge size resulted in the installation of some grommets that were too large to provide an effective seal. As a result, some of the seals failed pressure tests that were designed to simulate post-LOCA pressures. During the investigation of the grommet leakage problem, the Robinson staff also checked the torque on the conduit seal union nuts that are used to compress the seals. EGS Corporation recommends that the union nuts be torqued to 50 ft-lb. On approximately half of the 90 seals inspected, the union nut moved about 1/4 inch when this torque was applied. EGS Corporation reports that 1/4 inch of movement does not necessarily indicate a degraded seal but recommends that the correct torque be verified on a representative sample of installed conduit seals

Seals in nuclear reactors

International Nuclear Information System (INIS)

1979-01-01

The seals described are for use in a nuclear reactor where there are fuel assemblies in a vessel, an inlet and an outlet for circulating a coolant in heat transfer relationship with the fuel assemblies and a closure head on the vessel in a tight fluid relationship. The closure head comprises rotatable plugs which have mechanical seals disposed in the annulus around each plug while allowing free rotation of the plug when the seal is not actuated. The seal is usually an elastomer or copper. A means of actuating the seal is attached for drawing it vertically into the annulus for sealing. When the reactor coolant is liquid sodium, contact with oxygen must be avoided and argon cover gas fills the space between the bottom of the closure head and the coolant liquid level and the annuli in the closure head. (U.K.)

Investigation of positive shaft seals

Science.gov (United States)

Pfouts, J. O.

1970-01-01

Welded metal bellows secondary seals prevent secondary seal leakage with a minimum number of potential leak paths. High performance seal is obtained by controlling the potentially unstable seal-face movements induced by mechanical vibrations and fluid pressure pulsations.

Continuous improvement of pump seals

International Nuclear Information System (INIS)

Wong, W.; Eyvindson, A.; Rhodes, D.B.

2003-01-01

Pump seal reliability continues to be an area needing improvement and ongoing vigilance. Methods have been developed for identifying and assessing factors relating to seal performance, selecting the most relevant ones for a specific station, and then focusing on the most significant aspects and how to improve. Discussion invariably addresses maintenance practices, seal design, monitoring capabilities, operating conditions, transients, and pump and motor design. Success in reliability improvement requires ongoing dialogue among the station operators, pump manufacturers and seal designers. AECL CAN-seals lead the nuclear industry in reliability and seal life. They effectively save operators millions of dollars in outage time and person-rem. This paper describes some of the significant developments in AECL's ongoing program in seal R and D, as well as recent new installations following the most demanding seal qualification programs to date. (author)

Ferrules seals

Science.gov (United States)

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.

Research on swelling clays and bitumen as sealing materials for radioactive waste repositories

International Nuclear Information System (INIS)

Allison, J.A.; Wilson, J.; Mawditt, J.M.; Hurt, J.C.

1990-10-01

This report describes a programme of research to investigate the performance of composite seals comprising juxtaposed blocks of highly compacted bentonite clay and bitumen. It is shown that interaction of the materials can promote a self-sealing mechanism which prevents weather penetration, even when defects are present in the bitumen layer. Factors affecting seal performance are examined by means of laboratory experiments, and implications for the design of repository backfilling and sealing systems are discussed. It is concluded that design principles and material specifications should be further developed on the basis of large scale experiments. (author)

A magnetic fluid seal for rotary blood pumps: effects of seal structure on long-term performance in liquid.

Science.gov (United States)

Mitamura, Yoshinori; Takahashi, Sayaka; Amari, Shuichi; Okamoto, Eiji; Murabayashi, Shun; Nishimura, Ikuya

2011-03-01

A magnetic fluid (MF) seal enables mechanical contact-free rotation of the shaft and hence has excellent durability. The performance of an MF seal, however, has been reported to decrease in liquids. We developed an MF seal that has a "shield" mechanism, and a new MF with a higher magnetization of 47.9 kA/m. The sealing performance of the MF seal installed in a rotary blood pump was studied. Three types of MF seals were used. Seal A was a conventional seal without a shield. Seal B had the same structure as that of Seal A, but the seal was installed at 1 mm below liquid level. Seal C was a seal with a shield and the MF was set at 1 mm below liquid level. Seal A failed after 6 and 11 days. Seal B showed better results (20 and 73 days). Seal C showed long-term durability (217 and 275 days). The reason for different results in different seal structures was considered to be different flow conditions near the magnetic fluid. Fluid dynamics near the MF in the pump were analyzed using computational fluid dynamics (CFD) software. We have developed an MF seal with a shield that works in liquid for >275 days. The MF seal is promising as a shaft seal for rotary blood pumps.

Borehole sealing method and apparatus

International Nuclear Information System (INIS)

Hartley, J.N.; Jansen, G. Jr.

1977-01-01

A method and apparatus is described for sealing boreholes in the earth. The borehole is blocked at the sealing level, and a sealing apparatus capable of melting rock and earth is positioned in the borehole just above seal level. The apparatus is heated to rock-melting temperature and powdered rock or other sealing material is transported down the borehole to the apparatus where it is melted, pooling on the mechanical block and allowed to cool and solidify, sealing the hole. Any length of the borehole can be sealed by slowly raising the apparatus in the borehole while continuously supplying powdered rock to the apparatus to be melted and added to the top of the column of molten and cooling rock, forming a continuous borehole seal. The sealing apparatus consists of a heater capable of melting rock, including means for supplying power to the heater, means for transporting powdered rock down the borehole to the heater, means for cooling the apparatus and means for positioning the apparatus in the borehole. 5 claims, 1 figure

Dismantling, conditioning and repatriation of disused sealed radioactive sources

International Nuclear Information System (INIS)

Aguilar, S.L.; Miranda, C.A.; Saire, A.E.; Ontiveros, G.P.

2015-01-01

In Bolivia sealed radioactive sources for medical, industrial and research applications are used; radioactive sources containing a wide range of radionuclides and have different levels of activity and half-lives, they generated a problem when they stop being used. At the end of its useful life these sources are considered obsolete. However, residual levels of radioactivity, which have these sources can be high constituting a potential hazard to personnel and applies to those who benefit from its use and the general public. The aim of this work has been focused mainly on safety issues in the safe handling and management of disused sealed sources. Assignments listed below: 1. Dismantling; 2. Packaging; 3. Return of disused sealed radioactive sources. The actions taken were carried out by the technical teams of the Bolivian Institute of Nuclear Science and Technology (IBTEN) and Los Alamos National Laboratory (LANS) which supports the program 'Global Threat Reduction Initiative's' (GTRI) in the implementation of 'Off -site Source Recovery Program' (OSRP). [es

Closure and Sealing Design Calculation

International Nuclear Information System (INIS)

T. Lahnalampi; J. Case

2005-01-01

The purpose of the ''Closure and Sealing Design Calculation'' is to illustrate closure and sealing methods for sealing shafts, ramps, and identify boreholes that require sealing in order to limit the potential of water infiltration. In addition, this calculation will provide a description of the magma that can reduce the consequences of an igneous event intersecting the repository. This calculation will also include a listing of the project requirements related to closure and sealing. The scope of this calculation is to: summarize applicable project requirements and codes relating to backfilling nonemplacement openings, removal of uncommitted materials from the subsurface, installation of drip shields, and erecting monuments; compile an inventory of boreholes that are found in the area of the subsurface repository; describe the magma bulkhead feature and location; and include figures for the proposed shaft and ramp seals. The objective of this calculation is to: categorize the boreholes for sealing by depth and proximity to the subsurface repository; develop drawing figures which show the location and geometry for the magma bulkhead; include the shaft seal figures and a proposed construction sequence; and include the ramp seal figure and a proposed construction sequence. The intent of this closure and sealing calculation is to support the License Application by providing a description of the closure and sealing methods for the Safety Analysis Report. The closure and sealing calculation will also provide input for Post Closure Activities by describing the location of the magma bulkhead. This calculation is limited to describing the final configuration of the sealing and backfill systems for the underground area. The methods and procedures used to place the backfill and remove uncommitted materials (such as concrete) from the repository and detailed design of the magma bulkhead will be the subject of separate analyses or calculations. Post-closure monitoring will not

Salt repository sealing materials development program: 5-year work plan

International Nuclear Information System (INIS)

Myers, L.B.

1986-06-01

This plan covers 5 years (fiscal years 1986 through 1990) of work in the repository sealing materials program to support design decisions and licensing activities for a salt repository. The plan covers a development activity, not a research activity. There are firm deliverables as the end points of each part of the work. The major deliverables are: development plans for code development and materials testing; seal system components models; seal system performance specifications; seal materials specifications; and seal materials properties ''handbook.'' The work described in this plan is divided into three general tasks as follows: mathematical modeling; materials studies (salt, cementitious materials, and earthen materials); and large-scale testing. Each of the sections presents an overview, status, planned activities, and summary of program milestones. This plan will be the starting point for preparing the development plans described above, but is subject to change if preparation of the work plan indicates that a different approach or sequence is preferable to achieve the ultimate goal, i.e., support of design and licensing

Prospective randomized trial compares suction versus water seal for air leaks.

Science.gov (United States)

Cerfolio, R J; Bass, C; Katholi, C R

2001-05-01

Surgeons treat air leaks differently. Our goal was to evaluate whether it is better to place chest tubes on suction or water seal for stopping air leaks after pulmonary surgery. A second goal was to evaluate a new classification system for air leaks that we developed. Patients were prospectively randomized before surgery to receive suction or water seal to their chest tubes on postoperative day (POD) #2. Air leaks were described and quantified daily by a classification system and a leak meter. The air-leak meter scored leaks from 1 (least) to 7 (greatest). The group randomized to water seal stayed on water seal unless a pneumothorax developed. On POD #2, 33 of 140 patients had an air leak. Eighteen patients had been preoperatively randomized to water seal and 15 to suction. Air leaks resolved in 12 (67%) of the water seal patients by the morning of POD #3. All 6 patients whose air leak did not stop had a leak that was 4/7 or greater (p leak meter. Of the 15 patients randomized to suction, only 1 patient's air leak (7%) resolved by the morning of POD #3. The randomization aspect of the trial was ended and statistical analysis showed water seal was superior (p = 0.001). The remaining 14 patients were then placed to water seal and by the morning of POD #4, 13 patients' leaks had stopped. Of the 32 total patients placed to seal, 7 (22%) developed a pneumothorax and 6 of these 7 patients had leaks that were 4/7 or greater (p = 0.001). Placing chest tubes on water seal seems superior to wall suction for stopping air leaks after pulmonary resection. However, water seal does not stop expiratory leaks that are 4/7 or greater. Pneumothorax may occur when chest tubes are placed on seal with leaks this large.

Sealing properties of mechanical seals for an axial flow blood pump.

Science.gov (United States)

Tomioka, J; Mori, T; Yamazaki, K; Koyanagi, H

1999-08-01

A miniature intraventricular axial flow blood pump for left ventricular support is under development. One of the key technologies required for such pumps is sealing of the motor shaft. In this study, to prevent blood backflow into the motor side, mechanical seals were developed and their sealing properties investigated. In the experimental apparatus, the mechanical seal separated the bovine blood on the chamber side from the cooling water on the motor side. A leakage of the blood was measured by inductively coupled plasma (ICP) light emission analysis. The rate of hemolysis was measured by the cyanmethemoglobin method. Frictional torque acting on the shaft was measured by a torque transducer. In the experiments, the rotational speed of the shaft was changed from 1,000 to 10,000 rpm, and the contact force of the seal faces was changed from 1.96 to 4.31 N. To estimate lubrication regimes, the Stribeck curve, a diagram of the coefficient of friction against the bearing characteristic G number, was drawn. The results of the experiments showed that both the leakage of blood and the rate of hemolysis were very small. The friction loss was also very small. The mechanical seal was operated in various lubrication regimes, from a fluid lubrication regime to a mixed lubrication regime.

Development of laser beam welding for the lip seal configuration

International Nuclear Information System (INIS)

Yadav, Ashish; Joshi, Jaydeep; Singh, Dhananjay Kumar; Natu, Harshad; Rotti, Chandramouli; Bandyopadhyay, Mainak; Chakraborty, Arun

2015-01-01

Highlights: • Laser welding parameter optimization for required weld penetration. • Parametric study of actual scenarios like air gap, plate & beam misalignment. • Destructive and non-destructive examination of the welds and He-leak testing. - Abstract: A vacuum seal using the lip sealing technique is emerging as the most likely choice for fusion devices, to comply with the requirement of maintainability. The welding technology considered for lip sealing is laser welding, due to the attributes of small spot diameter, low concentrated heat input, high precision and penetration. To establish the process, an experiment has been conducted on a sample size of 150 mm × 50 mm having thickness of 2 mm, material AISI304L to assess the dependence of beam parameters like, laser power, speed and focusing distance on penetration and quality of weld joint. Further, the assessment of the effect of welding set-up variables like air-gap between plates, plate misalignment, and laser beam misalignment on the weld quality is also required. This paper presents the results of this experimental study and also the plan for developing a large (∼10 m) size laser welded seal, that simulates, appropriately, the configuration required in large dimension fusion devices.

Development of laser beam welding for the lip seal configuration

Energy Technology Data Exchange (ETDEWEB)

Yadav, Ashish, E-mail: ashish.yadav@iter-india.org [ITER-India, Institute for Plasma Research, Sector 25, Gandhinagar 382016, Gujarat (India); Joshi, Jaydeep; Singh, Dhananjay Kumar [ITER-India, Institute for Plasma Research, Sector 25, Gandhinagar 382016, Gujarat (India); Natu, Harshad [Magod Laser Machining Pvt. Ltd., KIADB Ind. Area, Jigani, Anekal Taluk, Bengaluru 560105 (India); Rotti, Chandramouli; Bandyopadhyay, Mainak; Chakraborty, Arun [ITER-India, Institute for Plasma Research, Sector 25, Gandhinagar 382016, Gujarat (India)

2015-10-15

Highlights: • Laser welding parameter optimization for required weld penetration. • Parametric study of actual scenarios like air gap, plate & beam misalignment. • Destructive and non-destructive examination of the welds and He-leak testing. - Abstract: A vacuum seal using the lip sealing technique is emerging as the most likely choice for fusion devices, to comply with the requirement of maintainability. The welding technology considered for lip sealing is laser welding, due to the attributes of small spot diameter, low concentrated heat input, high precision and penetration. To establish the process, an experiment has been conducted on a sample size of 150 mm × 50 mm having thickness of 2 mm, material AISI304L to assess the dependence of beam parameters like, laser power, speed and focusing distance on penetration and quality of weld joint. Further, the assessment of the effect of welding set-up variables like air-gap between plates, plate misalignment, and laser beam misalignment on the weld quality is also required. This paper presents the results of this experimental study and also the plan for developing a large (∼10 m) size laser welded seal, that simulates, appropriately, the configuration required in large dimension fusion devices.

Investigating the sealing capacity of a seal system in rock salt (DOPAS project)

Energy Technology Data Exchange (ETDEWEB)

Jantschik, Kyra; Moog, Helge C.; Czaikowski, Oliver; Wieczorek, Klaus [Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) gGmbH, Braunschweig (Germany)

2016-11-15

This paper describes research and development work on plugging and sealing repositories, an issue of fundamental importance for the rock salt option which represents one of the three European repository options, besides the clay rock and the crystalline rock options. The programme aims at providing experimental data needed for the theoretical analysis of the long-term sealing capacity of concrete- based sealing materials. In order to demonstrate hydro-mechanical material stability under representative load scenarios, a comprehensive laboratory testing programme is carried out. This comprises investigation of the sealing capacity of the combined seal system and impact of the so-called excavation-damaged zones (EDZ) as well as investigation of the hydro-chemical long-term stability of the seal in contact with different brines under diffusive and advective conditions. This paper presents experimental approaches and preliminary results from laboratory investigations on salt concrete and combined systems as obtained to date.

Regenerator cross arm seal assembly

Science.gov (United States)

Jackman, Anthony V.

1988-01-01

A seal assembly for disposition between a cross arm on a gas turbine engine block and a regenerator disc, the seal assembly including a platform coextensive with the cross arm, a seal and wear layer sealingly and slidingly engaging the regenerator disc, a porous and compliant support layer between the platform and the seal and wear layer porous enough to permit flow of cooling air therethrough and compliant to accommodate relative thermal growth and distortion, a dike between the seal and wear layer and the platform for preventing cross flow through the support layer between engine exhaust and pressurized air passages, and air diversion passages for directing unregenerated pressurized air through the support layer to cool the seal and wear layer and then back into the flow of regenerated pressurized air.

Aerial surveys of seals at Rødsand seal sanctuary and adjacent haul-out sites

DEFF Research Database (Denmark)

Teilmann, J.; Dietz, R.; Edren, Susi M.C.

This report describes the preliminary results of aerial surveys at Rødsand seal sanctuary, southeast Denmark and adjacent seal haul-out sites in southwestern Baltic. The work was carried out in connection with studies of potential effects of the Nysted offshore wind farm. Rødsand seal sanctuary...... is a part of seal management area 4, and the area is believed to hold a more or less closed population with little exchange to other areas. Although the harbour seal is relatively stationary there may be movements between the haul-out sites in the area. A possible reaction to disturbance from...... the construction and operation of the wind farm may be that the seals use other haul-out sites to a higher extend....

Harbor seal vibrissa morphology suppresses vortex-induced vibrations.

Science.gov (United States)

Hanke, Wolf; Witte, Matthias; Miersch, Lars; Brede, Martin; Oeffner, Johannes; Michael, Mark; Hanke, Frederike; Leder, Alfred; Dehnhardt, Guido

2010-08-01

Harbor seals (Phoca vitulina) often live in dark and turbid waters, where their mystacial vibrissae, or whiskers, play an important role in orientation. Besides detecting and discriminating objects by direct touch, harbor seals use their whiskers to analyze water movements, for example those generated by prey fish or by conspecifics. Even the weak water movements left behind by objects that have passed by earlier can be sensed and followed accurately (hydrodynamic trail following). While scanning the water for these hydrodynamic signals at a swimming speed in the order of meters per second, the seal keeps its long and flexible whiskers in an abducted position, largely perpendicular to the swimming direction. Remarkably, the whiskers of harbor seals possess a specialized undulated surface structure, the function of which was, up to now, unknown. Here, we show that this structure effectively changes the vortex street behind the whiskers and reduces the vibrations that would otherwise be induced by the shedding of vortices from the whiskers (vortex-induced vibrations). Using force measurements, flow measurements and numerical simulations, we find that the dynamic forces on harbor seal whiskers are, by at least an order of magnitude, lower than those on sea lion (Zalophus californianus) whiskers, which do not share the undulated structure. The results are discussed in the light of pinniped sensory biology and potential biomimetic applications.

Epizootics in harbour seals (Phoca vitulina: clinical aspects

Directory of Open Access Journals (Sweden)

Ursula Siebert

2010-09-01

Full Text Available Epizootic diseases causing considerable mortality in harbour seal populations have mainly been reported from the waters of the United States and Europe. Such die-offs were largely attributable to viral infections. Several hundred individuals died from respiratory infections caused by Influenza A viruses at the coast of New England, USA, in 1979, 1980 and 1982. More than 53,000 harbour seals were killed in European waters by Phocine Distemper Virus (PDV, a morbillivirus,in two outbreaks in 1988 and 2002. For several other epizootics of smaller scale in the waters of the Atlantic and Pacific coast of the USA and, most recently, in Danish and Swedish waters in 2007 the causes remain unclear, although characteristic respiratory symptoms and interstitial pneumonia suspicious of viral etiology were detected as well as occasionally bacterial infections caused by Erysipelothrix rhusiopathiae and Pseudomonas aeruginosa. Mass mortalities caused by biotoxins, direct human interactions or changes in oceanographic conditions have so far not been described for harbour seals. However, high organochlorine loads detected in European harbour seal populations and suspected to impede immune functions, were considered an aggravating factor in the 1988 morbillivirus epizootic. Establishing supranational stranding networks is a key prerequisite for the detection of future unusual die-offs in marine mammals. Detailed post-mortem investigations of all organ systems are essential for targeted etiological studies towards the causes of mass mortalities in seals.

Ceramic/metal seals. [refractory materials for hermetic seals for lighium-metal sulfide batteries

Science.gov (United States)

Bredbenner, A. M.

1977-01-01

Design criteria are discussed for a hermetic seal capable of withstanding the 450 C operating temperature of a lithium-metal sulfide battery system. A mechanical seal consisting of two high strength alloy metal sleeves welded or brazed to a conductor assembly and pressed onto a ceramic is described. The conductor center passes through the ceramic but is not sealed to it. The seal is effected on the outside of the taper where the tubular part is pressed down over and makes contact.

Nuclear instrumentation cable end seal

International Nuclear Information System (INIS)

Cannon, C.P.; Brown, D.P.

1979-01-01

An improved coaxial end seal for hermetically sealed nuclear instrumentation cable exhibiting an improved breakdown pulse noise characteristic under high voltage, high temperature conditions is described. A tubular insulator body has metallized interior and exterior surface portions which are braze sealed to a center conductor and an outer conductive sheath. The end surface of the insulator body which is directed toward the coaxial cable to which it is sealed has a recessed surface portion within which the braze seal material terminates

Turbine interstage seal with self-balancing capability

Science.gov (United States)

Mills, Jacob A; Jones, Russell B; Sexton, Thomas D

2017-09-26

An interstage seal for a turbine of a gas turbine engine, the interstage seal having a seal carrier with an axial extending seal tooth movable with a stator of the engine, and a rotor with a seal surface that forms the interstage seal with the seal tooth, where a magnetic force produced by two magnets and a gas force produced by a gas pressure acting on the seal carrier forms a balancing force to maintain a close clearance of the seal without the seal tooth contacting the rotor seal surfaces during engine operation. In other embodiments, two pairs of magnets produce first and second magnetic forces that balance the seal in the engine.

Enhanced sealing project (ESP): evolution of a full-sized concrete and bentonite shaft seal

International Nuclear Information System (INIS)

Dixon, D.A.; Priyanto, D.G.; Martino, J.B.; De Combarieu, M.; Johansson, R.; Korkeakoski, P.; Villagran, J.

2012-01-01

Document available in extended abstract form only. A full-scale shaft seal was designed and installed in the 5-m-diameter access shaft at Atomic Energy of Canada's (AECL's) Underground Research Laboratory (URL) at the point where he shaft intersects an ancient water-bearing, low-angle thrust fault in granitic rock. The seal, part of the permanent closure of the URL, consists of a 6-m-thick bentonite-based component sandwiched between 3-m-thick upper and lower, 3-m-thick concrete components. The bentonite-based component spans the fracture zone and extends approximately 1 m beyond the maximum identified extent of the fracture. This design was adopted in order to limit water from the deeper, saline regions mixing with the fresher, near-surface groundwater regime. The concrete components provide the mechanical confinement and an in situ compacted 40/60 mixture of bentonite clay and quartz sand provides the sealing component. Construction of the shaft seal was done as part of Canada's Nuclear Legacies Liability Program. However, monitoring the seal evolution was not part of the decommissioning program's mandate. In addition to accomplishing the permanent closure of the URL, this seal's construction provides a unique opportunity to instrument and monitor the evolution of a full-scale shaft seal as well as the recovery of the regional groundwater regime as the facility passively floods above the seal. A jointly funded monitoring project was developed by NWMO (Canada), SKB (Sweden), Posiva (Finland) and ANDRA (France) and since mid 2009 the thermal, hydraulic and mechanical evolution of the seal has been constantly monitored. The evolution of the type of seal being monitored in the ESP is of relevance to repository closure planning, gaining confidence in the functionality of shaft seals. Although constructed in a crystalline rock medium, the results of the ESP are expected to be relevant to the performance of seals in a variety of host rock types. The shaft seal has been

Reactor Coolant Pump seal issues and their applicability to new reactor designs

International Nuclear Information System (INIS)

Ruger, C.J.; Higgins, J.C.

1993-01-01

Reactor Coolant Pumps (RCPs) of various types are used to circulate the primary coolant through the reactor in most reactor designs. RCPs generally contain mechanical seals to limit the leakage of pressurized reactor coolant along the pump drive shaft into the containment. The relatively large number of RCP seal and seal auxiliary system failures experienced at US operating plants during the 1970's and early 1980's raised concerns from the US Nuclear Regulatory Commission (NRC) that gross failures may lead to reactor core uncovery and subsequent core damage. Some seal failure events resulted in a loss of primary coolant to the containment at flow rates greater than the normal makeup capacity of Pressurized Water Reactor (PWR) plants. This is an example of RCP seal failures resulting in a small Loss of Coolant Accident (LOCA). This paper discusses observed and potential causes of RCP seal failure and the recommendations for limiting the likelihood of a seal induced small LOCA. Issues arising out of the research supporting these recommendations and subsequent public comments by the utility industry on them, serve as lessons learned, which are applicable to the design of new reactor plants

Reactor coolant pump seal issues and their applicability to new reactor designs

International Nuclear Information System (INIS)

Ruger, C.J.; Higgins, J.C.

1993-01-01

Reactor Coolant Pumps (RCPs) of various types are used to circulate the primary coolant through the reactor in most reactor designs. RCPs generally contain mechanical seals to limit the leakage of pressurized reactor coolant along the pump drive shaft into the containment. The relatively large number of RCP seal and seal auxiliary system failures experienced at U.S. operating plants during the 1970's and early 1980's raised concerns from the U.S. Nuclear Regulatory Commission (NRC) that gross failures may lead to reactor core uncovery and subsequent core damage. Some seal failure events resulted in a loss of primary coolant to the containment at flow rates greater than the normal makeup capacity of Pressurized Water Reactor (PWR) plants. This is an example of RCP seal failures resulting in a small Loss of Coolant Accident (LOCA). This paper discusses observed and potential causes of RCP seal failure and the recommendations for limiting the likelihood of a seal induced small LOCA. Issues arising out of the research supporting these recommendations and subsequent public comments by the utility industry on them, serve as lessons learned, which are applicable to the design of new reactor plants

Sealing a conduit end

International Nuclear Information System (INIS)

Mentz, R.M.

1993-01-01

An apparatus for sealing or blocking conduits, such as the primary nozzles of a nuclear steam generator is described. It includes an annular bracket sealingly attached to the open end of the nozzle, the bracket having a plurality of threaded holes therein. Mounted atop the bracket is a generally circular nozzle dam for covering the opening. Interposed between the nozzle dam and the bracket is an extrusion-resistant seal member having a plurality of apertures therethrough for receiving each bolt. The seal member is configured to resist extrusion by having laminated layers of differing hardnesses, so that the seal member will not laterally extrude away from each bolt in a manner that enlarges the aperture surrounding each bolt as the nozzle dam is bolted to the bracket. (author)

Hermetic Seal Leak Detection Apparatus

Science.gov (United States)

Kelley, Anthony R. (Inventor)

2013-01-01

The present invention is a hermetic seal leak detection apparatus, which can be used to test for hermetic seal leaks in instruments and containers. A vacuum tight chamber is created around the unit being tested to minimize gas space outside of the hermetic seal. A vacuum inducing device is then used to increase the gas chamber volume inside the device, so that a slight vacuum is pulled on the unit being tested. The pressure in the unit being tested will stabilize. If the stabilized pressure reads close to a known good seal calibration, there is not a leak in the seal. If the stabilized pressure reads closer to a known bad seal calibration value, there is a leak in the seal. The speed of the plunger can be varied and by evaluating the resulting pressure change rates and final values, the leak rate/size can be accurately calculated.

Double angle seal forming lubricant film

Science.gov (United States)

Ernst, William D.

1984-01-01

A lubricated piston rod seal which inhibits gas leaking from a high pressure chamber on one side of the seal to a low pressure chamber on the other side of the seal. A liquid is supplied to the surface of the piston rod on the low pressure side of the seal. This liquid acts as lubricant for the seal and provides cooling for the rod. The seal, which can be a plastic, elastomer or other material with low elastic modulus, is designed to positively pump lubricant through the piston rod/seal interface in both directions when the piston rod is reciprocating. The capacity of the seal to pump lubricant from the low pressure side to the high pressure side is less than its capacity to pump lubricant from the high pressure side to the low pressure side which ensures that there is zero net flow of lubricant to the high pressure side of the seal. The film of lubricant between the seal and the rod minimizes any sliding contact and prevents the leakage of gas. Under static conditions gas leakage is prevented by direct contact between the seal and the rod.

Shaft and tunnel sealing considerations

International Nuclear Information System (INIS)

Kelsall, P.C.; Shukla, D.K.

1980-01-01

Much of the emphasis of previous repository sealing research has been placed on plugging small diameter boreholes. It is increasingly evident that equal emphasis should now be given to shafts and tunnels which constitute more significant pathways between a repository and the biosphere. The paper discusses differences in requirements for sealing shafts and tunnels as compared with boreholes and the implications for seal design. Consideration is given to a design approach for shaft and tunnel seals based on a multiple component design concept, taking into account the requirements for retrievability of the waste. A work plan is developed for the future studies required to advance shaft and tunnel sealing technology to a level comparable with the existing technology for borehole sealing

Recent advances in magnetic liquid sealing

International Nuclear Information System (INIS)

Raj, K.; Stahl, P.; Bottenberg, W.; True, D.; Martis, G.; Zook, C.

1979-01-01

In this paper recent work in design and testing of two special magnetic liquid seals extending the state-of-the-art of ferrofluidic sealing is discussed. These custom seals are a moving belt edge seal and an exclusion seal. The first seal provides a hermetic barrier to solid particulates expected to be present in enclosed nuclear environments. The second seal is used on a magnetic disk drive spindle and reduces the particulate contaminants in the memory disk pack area by up to three orders of magnitude. In addition, bearing life in the spindle is found to be doubled due to reduction of operating temperature. The fundamentals of magnetic fluid sealing are presented in terms of magnetic circuit design and physical properties of ferrofluids

Seal Related Development Activities at EG/G

Science.gov (United States)

Greiner, Harold F.

1991-01-01

Seal related development activities including modeling, analysis, and performance testing are described for several current seal related projects. Among the current seal related projects are the following: high pressure gas sealing systems for turbomachinery; brush seals for gas path sealing in gas turbines; and tribological material evaluation for wear surfaces in sealing systems.

SEALING SIMULATED LEAKS

Energy Technology Data Exchange (ETDEWEB)

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.

Fog seal guidelines.

Science.gov (United States)

2003-10-01

Fog seals are a method of adding asphalt to an existing pavement surface to improve sealing or waterproofing, prevent further stone loss by holding aggregate in place, or simply improve the surface appearance. However, inappropriate use can result in...

Initial field testing definition of subsurface sealing and backfilling tests in unsaturated tuff

International Nuclear Information System (INIS)

Fernandez, J.A.; Case, J.B.; Tyburski, J.R.

1993-05-01

This report contains an initial definition of the field tests proposed for the Yucca Mountain Project repository sealing program. The tests are intended to resolve various performance and emplacement concerns. Examples of concerns to be addressed include achieving selected hydrologic and structural requirements for seals, removing portions of the shaft liner, excavating keyways, emplacing cementitious and earthen seals, reducing the impact of fines on the hydraulic conductivity of fractures, efficient grouting of fracture zones, sealing of exploratory boreholes, and controlling the flow of water by using engineered designs. Ten discrete tests are proposed to address these and other concerns. These tests are divided into two groups: Seal component tests and performance confirmation tests. The seal component tests are thorough small-scale in situ tests, the intermediate-scale borehole seal tests, the fracture grouting tests, the surface backfill tests, and the grouted rock mass tests. The seal system tests are the seepage control tests, the backfill tests, the bulkhead test in the Calico Hills unit, the large-scale shaft seal and shaft fill tests, and the remote borehole sealing tests. The tests are proposed to be performed in six discrete areas, including welded and non-welded environments, primarily located outside the potential repository area. The final selection of sealing tests will depend on the nature of the geologic and hydrologic conditions encountered during the development of the Exploratory Studies Facility and detailed numerical analyses. Tests are likely to be performed both before and after License Application

Reactor vessel sealing plug

International Nuclear Information System (INIS)

Dooley, R.A.

1986-01-01

An apparatus is described for sealing a cold leg nozzle of a nuclear reactor pressure vessel from a remote location comprising: at least one sealing plug for mechanically sealing the nozzle from the inside of the reactor pressure vessel. The sealing plug includes a plate and a cone assembly having an end part receptive in the nozzle, the plate being axially moveable relative to the cone assembly. The plate and cone assembly have confronting bevelled edges defining an opening therebetween. A primary O-ring is disposed about the opening and is supported on the bevelled edges, the plate being guidably mounted to the cone assembly for movement toward the cone assembly to radially expand the primary O-ring into sealing engagement with the nozzle. A means is included for providing relative movement between the outer plate and the cone assembly

Detection of seal contamination in heat-sealed food packaging based on active infrared thermography

Science.gov (United States)

D'huys, Karlien; Saeys, Wouter; De Ketelaere, Bart

2015-05-01

In the food industry packaging is often applied to protect the product from the environment, assuring quality and safety throughout shelf life if properly performed. Packaging quality depends on the material used and the closure (seal). The material is selected based on the specific needs of the food product to be wrapped. However, proper closure of the package is often harder to achieve. One problem possibly jeopardizing seal quality is the presence of food particles between the seal. Seal contamination can cause a decreased seal strength and thus an increased packaging failure risk. It can also trigger the formation of microchannels through which air and microorganisms can enter and spoil the enclosed food. Therefore, early detection and removal of seal-contaminated packages from the production chain is essential. In this work, a pulsed-type active thermography method using the heat of the sealing bars as an excitation source was studied for detecting seal contamination. The cooling profile of contaminated seals was recorded. The detection performance of four processing methods (based on a single frame, a fit of the cooling profile, pulsed phase thermography and a matched filter) was compared. High resolution digital images served as a reference to quantify contamination. The lowest detection limit (equivalent diameter of 0.63 mm) and the lowest processing time (0.42 s per sample) were obtained for the method based on a single frame. Presumably, practical limitations in the recording stage prevented the added value of active thermography to be fully reflected in this application.

Catch history and status of the harbour seal (Phoca vitulina in Greenland

Directory of Open Access Journals (Sweden)

Aqqalu Rosving-Asvid

2010-09-01

Full Text Available The number of harbour seals (Phoca vitulina in West Greenland declined rapidly after the 1950s and the seals have now abandoned their traditional haulout locations along the Greenland west coast. However, in recent years, a previously undetected group of about 60-100 harbour seals has been observed approximately 80 km upstream in a large river, and some traditional hauloutlocations are still in use near the south-eastern tip of Greenland. A small number of harbour seals is caught annually far from any of these locations, indicating that other groups might live unnoticed. Catch statistics provide the best evidence of the presence and locations of these remnant harbour seals. Therefore efforts were made to validate the recent catch statistics and to describe the catch history for the past 60 years. The catch statistics were also used to estimate plausibleranges of past and present numbers of harbour seals based on the assumption that hunting has caused the observed decline. The total number of harbour seals in Greenland according to these estimates was about 3,000 in 1950 and fewer than 1,000 in 2007. The number of harbour seals caught in the southernmost part of Greenland has, unlike in the rest of Greenland, increased significantly in some of the recent years. This change seems to be related to changes in the amount of drift ice. Drift ice reduces the frequency of contact between hunters and harbour seals in South Greenland and above normal quantities of drift ice from the mid 1960s to the mid 1980s probably allowed these seals to increase in numbers. Record low inflow of drift ice in some of the recent years, however, has resulted in record high catches, which likely have reduced the seals again. The remaining harbour seals in Greenland are few and without protection these sealsare potentially in danger of extinction.

Sealed liquid helium cryostats for mobile superconducting magnets

International Nuclear Information System (INIS)

Mulhall, B.E.; Rhodes, R.G.

1976-01-01

The predicted behaviour of the sealed cryostat system, which has been designed for the niobium-titanium superconducting coils of the on-board refrigerator of the small Wolfson electrodynamically levitated vehicle now under development, is summarized. Calculations suggest that the time taken by a sealed liquid helium cryostat to reach a specified final temperature is reasonably insensitive to the level of initial filling. Moreover, with a sufficiently large initial fill (for example, 70%) two or possibly three such temperature cycles, separated by the simple process of gas recovery, should be possible before replenishment of the helium is necessary. The useful time of operation of the cryostat between transfers of liquid helium is then not very much less than can be obtained with a freely boiling bath of liquid. For the low pressures involved the sealed cryostat is probably not much heavier or more complex than the open cryostat, and thus is ideal for a mobile application. (U.K.)

Shaft Seal Compensates for Cold Flow

Science.gov (United States)

Myers, W. N.; Hein, L. A.

1985-01-01

Seal components easy to install. Ring seal for rotating or reciprocating shafts spring-loaded to compensate for slow yielding (cold flow) of sealing material. New seal relatively easy to install because components preassembled, then installed in one piece.

Film riding seals for rotary machines

Science.gov (United States)

Bidkar, Rahul Anil; Sarawate, Neelesh Nandkumar; Wolfe, Christopher Edward; Ruggiero, Eric John; Raj Mohan, Vivek Raja

2017-03-07

A seal assembly for a rotary machine is provided. The seal assembly includes multiple sealing device segments disposed circumferentially intermediate to a stationary housing and a rotor. Each of the segments includes a shoe plate with a forward-shoe section and an aft-shoe section having one or more labyrinth teeth therebetween facing the rotor. The sealing device includes a stator interface element having a groove or slot for allowing disposal of a spline seal for preventing segment leakages. The sealing device segment also includes multiple bellow springs or flexures connected to the shoe plate and to the stator interface element. Further, the sealing device segments include a secondary seal integrated with the stator interface element at one end and positioned about the multiple bellow springs or flexures and the shoe plate at the other end.

Low-Torque Seal Development

Science.gov (United States)

Lattime, Scott B.; Borowski, Richard

2009-01-01

The EcoTurn Class K production prototypes have passed all AAR qualification tests and received conditional approval. The accelerated life test on the second set of seals is in progress. Due to the performance of the first set, no problems are expected.The seal has demonstrated superior performance over the HDL seal in the test lab with virtually zero torque and excellent contamination exclusion and grease retention.

Pressure vessels and methods of sealing leaky tubes disposed in pressure vessels

International Nuclear Information System (INIS)

Larson, G.C.

1980-01-01

This invention relates to pressure vessels and to methods of sealing leaky tubes in them and is especially applicable to pressure vessels in the form of sheet-and-tube type heat exchangers constructed with a large number of relatively small diameter tubes grouped in a bundle. To seal off a leaky tube in such a heat exchanger an explosive activated plug in the form of a hollow metal body is used, inserted at each end of the tube to be sealed. Using the arrangement of pressure vessel and associated tube sheets and the explosive activated plug method of sealing a leaky tube as described in this invention it is claimed that distortion of the adjacent tubes and the tube sheets is reduced when the explosive activated plugs are detonated. (U.K.)

Global variations of large megathrust earthquake rupture characteristics

Science.gov (United States)

Kanamori, Hiroo

2018-01-01

Despite the surge of great earthquakes along subduction zones over the last decade and advances in observations and analysis techniques, it remains unclear whether earthquake complexity is primarily controlled by persistent fault properties or by dynamics of the failure process. We introduce the radiated energy enhancement factor (REEF), given by the ratio of an event’s directly measured radiated energy to the calculated minimum radiated energy for a source with the same seismic moment and duration, to quantify the rupture complexity. The REEF measurements for 119 large [moment magnitude (Mw) 7.0 to 9.2] megathrust earthquakes distributed globally show marked systematic regional patterns, suggesting that the rupture complexity is strongly influenced by persistent geological factors. We characterize this as the existence of smooth and rough rupture patches with varying interpatch separation, along with failure dynamics producing triggering interactions that augment the regional influences on large events. We present an improved asperity scenario incorporating both effects and categorize global subduction zones and great earthquakes based on their REEF values and slip patterns. Giant earthquakes rupturing over several hundred kilometers can occur in regions with low-REEF patches and small interpatch spacing, such as for the 1960 Chile, 1964 Alaska, and 2011 Tohoku earthquakes, or in regions with high-REEF patches and large interpatch spacing as in the case for the 2004 Sumatra and 1906 Ecuador-Colombia earthquakes. Thus, combining seismic magnitude Mw and REEF, we provide a quantitative framework to better represent the span of rupture characteristics of great earthquakes and to understand global seismicity. PMID:29750186

Refrigeration system with clearance seals

International Nuclear Information System (INIS)

Holland, N. J.

1985-01-01

In a refrigeration system such as a split Stirling system, fluid seals associated with the reciprocating displacer are virtually dragless clearance seals. Movement of the displacer relative to the pressure variations in the working volume of gas is retarded by a discrete braking element. Because it is not necessary that the brake providing any sealing action, the brake can be designed for greater durability and less dependence on ambient and operating temperatures. Similarly, the clearance seal can be formed of elements having low thermal expansion such that the seal is not temperature dependent. In the primary embodiments the braking element is a split friction brake

Rock sealing - interim report on the rock seealing project (stage 1)

International Nuclear Information System (INIS)

Pusch, R.; Boergesson, L.; Fredrikson, A.; Markstroem, I.; Erlstroem, M.; Ramqvist, G.; Gray, M.; Coons, B.

1988-09-01

The objective of the Sealing Project is to find ways of sealing finely fractured rock by grouting. This requires development of new injection technique as well as to identify materials which are sufficiently fluid to be groutable and acceptably low-previous and physically and chemically stable. The present report describes the results of the first two years of investigation (stage 1), which gave very positive results as concluded from a large field-scale test. (orig.)

Reactor cavity seal ring

International Nuclear Information System (INIS)

Hankinson, M.F.

1986-01-01

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

Facilitation of the PED analysis of large molecules by using global coordinates.

Science.gov (United States)

Jamróz, Michał H; Ostrowski, Sławomir; Dobrowolski, Jan Cz

2015-10-05

Global coordinates have been found to be useful in the potential energy distribution (PED) analyses of the following large molecules: [13]-acene and [33]-helicene. The global coordinate is defined based on much distanced fragments of the analysed molecule, whereas so far, the coordinates used in the analysis were based on stretchings, bendings, or torsions of the adjacent atoms. It has been shown that the PED analyses performed using the global coordinate and the classical ones can lead to exactly the same PED contributions. The global coordinates may significantly improve the facility of the analysis of the vibrational spectra of large molecules. Copyright © 2015 Elsevier B.V. All rights reserved.

THE CHALLENGE OF GLOBALIZATION FOR LARGE CHINESE FIRMS

OpenAIRE

Peter Nolan; Jin Zhang

2002-01-01

As China joins the World Trade Organization, the author questions whether China’s large firms will be able to compete on the global level playing field. Over the past two decades, Chinese large enterprises have undertaken extensive evolutionary change but, at the same time, the world’s leading firms have undergone a revolutionary transformation. Based on analysis of firms with the aerospace, oil and petrochemical industry, the authors conclude that China’s leading firms face critical challeng...

Process and device for in situ replacing sealing faces in large valves

International Nuclear Information System (INIS)

Francois, M.; Garit, J.; Mantes, G.

1995-01-01

A milling machine is fitted in the interior of the valve and first machines the sealing face of the opposite seat of the seat to be replaced so that this face can act as a reference for the tool and then machines out the seat ending up by machining a new recess for the replacement seat which is then inserted in position and fixed to the body of the valve by a circular welded joint. 23 figs

Design considerations for mechanical face seals

Science.gov (United States)

Ludwig, L. P.; Greiner, H. F.

1980-01-01

Two companion reports deal with design considerations for improving performance of mechanical face seals, one of family of devices used in general area of fluid sealing of rotating shafts. One report deals with basic seal configuration and other with lubrication of seal.

Design of Robust AMB Controllers for Rotors Subjected to Varying and Uncertain Seal Forces

DEFF Research Database (Denmark)

Lauridsen, Jonas Skjødt; Santos, Ilmar

2017-01-01

This paper demonstrates the design and simulation results of model based controllers for AMB systems, subjectedto uncertain and changing dynamic seal forces. Specifically, a turbocharger with a hole-pattern seal mounted acrossthe balance piston is considered. The dynamic forces of the seal, which...... are dependent on the operational conditions,have a significant effect on the overall system dynamics. Furthermore, these forces are considered uncertain.The nominal and the uncertainty representation of the seal model are established using results from conventionalmodelling approaches, i.e. CFD and Bulkflow......, and experimental results. Three controllers are synthesized: I) AnH∞ controller based on nominal plant representation, II) A µ controller, designed to be robust against uncertaintiesin the dynamic seal model and III) a Linear Parameter Varying (LPV) controller, designed to provide a unifiedperformance over a large...

Individuality in harp seal, Phoca groenlandica, pup vocalizations

NARCIS (Netherlands)

Van Opzeeland, IC; Van Parijs, SM

In gregarious breeders, parents often use individually stereotyped vocalizations as a cue to relocate offspring. Harp seals aggregate in large colonies on pack ice during the whelping season. During the 11-day lactation period, females alternate between periods at sea and attending their pup. If

EBR-II rotating plug seal maintenance

International Nuclear Information System (INIS)

Allen, K.J.

1986-01-01

The EBR-II rotating plug seals require frequent cleaning and maintenance to keep the plugs from sticking during fuel handling. Time consuming cleaning on the cover gas and air sides of the dip ring seal is required to remove oxidation and sodium reaction products that accumulate and stop plug rotation. Despite severely limited access, effective seal cleaning techniques have removed 11 800 lb (5 352 kg) of deposits from the seals since 1964. Temperature control modifications and repairs have also required major maintenance work. Suggested seal design recommendations could significantly reduce maintenance on future similar seals

Control Design of Active Magnetic Bearings for Rotors Subjected to Destabilising Seal Forces - Theory & Experiment

DEFF Research Database (Denmark)

Lauridsen, Jonas Skjødt

. At present, there is no generally accepted method for determination of dynamic seal forces. Therefore, large uncertainties must be expected when modelling dynamic seal forces and consequently also in rotor-dynamic stability analysis. This thesis focuses on i) closed loop identification of uncertain AMB...... parameters, ii) closed loop identification of unknown stiffness and damping coefficients of a dynamicseal model and iii) the design of AMB controllers to handle dynamic seal forces. Controllers that can guarantee stability and performance in the presence of uncertainseal forces are of special interest...... the uncertaintiesin seal forces and for LPV control synthesis, to compensate for known changes in seal forces due to changes in operating conditions. A rotor dynamic test facility with a rigid rotor, two radial AMBs and one annular test seal is used for i) closed loop identification of parameters in the AMB...

Haul-out behavior of harbor seals (Phoca vitulina in Hood Canal, Washington.

Directory of Open Access Journals (Sweden)

Josh M London

Full Text Available The goal of this study was to model haul-out behavior of harbor seals (Phoca vitulina in the Hood Canal region of Washington State with respect to changes in physiological, environmental, and temporal covariates. Previous research has provided a solid understanding of seal haul-out behavior. Here, we expand on that work using a generalized linear mixed model (GLMM with temporal autocorrelation and a large dataset. Our dataset included behavioral haul-out records from archival and VHF radio tag deployments on 25 individual seals representing 61,430 seal hours. A novel application for increased computational efficiency allowed us to examine this large dataset with a GLMM that appropriately accounts for temporal autocorellation. We found significant relationships with the covariates hour of day, day of year, minutes from high tide and year. Additionally, there was a significant effect of the interaction term hour of day : day of year. This interaction term demonstrated that seals are more likely to haul out during nighttime hours in August and September, but then switch to predominantly daylight haul-out patterns in October and November. We attribute this change in behavior to an effect of human disturbance levels. This study also examined a unique ecological event to determine the role of increased killer whale (Orcinus orca predation on haul-out behavior. In 2003 and 2005 these harbor seals were exposed to unprecedented levels of killer whale predation and results show an overall increase in haul-out probability after exposure to killer whales. The outcome of this study will be integral to understanding any changes in population abundance as a result of increased killer whale predation.

Repository Closure and Sealing Approach

International Nuclear Information System (INIS)

A.T. Watkins

2000-01-01

The scope of this analysis will be to develop the conceptual design of the closure seals and their locations in the Subsurface Facilities. The design will be based on the recently established program requirements for transitioning to the Site Recommendation (SR) design as outlined by ''Approach to Implementing the Site Recommendation Baseline'' (Stroupe 2000) and the ''Monitored Geologic Repository Project Description Document'' (CRWMS M andO 1999b). The objective of this analysis will be to assist in providing a description for the Subsurface Facilities System Description Document, Section 2 and finally to document any conclusions reached in order to contribute and provide support to the SR. This analysis is at a conceptual level and is considered adequate to support the SR design. The final closure barriers and seals for the ventilation shafts, and the north and south ramps will require these openings to be permanently sealed to limit excessive air and water inflows and prevent human intrusion. The major tasks identified with closure in this analysis are: (1) Developing the overall subsurface seal layout and identifying design and operational interfaces for the Subsurface Facilities. (2) Summarizing the general site conditions and general rock characteristic with respect to seal location and describing the seal selected. (3) Identify seal construction materials, methodology of construction and strategic locations including design of the seal and plugs. (4) Discussing methods to prevent human intrusion

Air riding seal with purge cavity

Science.gov (United States)

Sexton, Thomas D; Mills, Jacob A

2017-08-15

An air riding seal for a turbine in a gas turbine engine, where an annular piston is axial moveable within an annular piston chamber formed in a stator of the turbine and forms a seal with a surface on the rotor using pressurized air that forms a cushion in a pocket of the annular piston. A purge cavity is formed on the annular piston and is connected to a purge hole that extends through the annular piston to a lower pressure region around the annular piston or through the rotor to an opposite side. The annular piston is sealed also with inner and outer seals that can be a labyrinth seal to form an additional seal than the cushion of air in the pocket to prevent the face of the air riding seal from overheating.

Seals in nuclear reactors

International Nuclear Information System (INIS)

1979-01-01

The aim of this invention is the provision of improved seals for reactor vessels in which fuel assemblies are located together with inlets and outlets for the circulation of a coolant. The object is to provide a seal arrangement for the rotatable plugs of nuclear reactor closure heads which has good sealing capacities over a wide gap during operation of the reactor but which also permits uninhibited rotation of the plugs for maintenance. (U.K.)

Self-acting and hydrodynamic shaft seals

Science.gov (United States)

Ludwig, L. P.

1973-01-01

Self-acting and hydrodynamic seals are described. The analytical procedures are outlined for obtaining a seal force balance and the operating film thickness. Particular attention is given to primary ring response (seal vibration) to rotating seat face runout. This response analysis revealed three different vibration modes. Proposed applications of self-acting seals in gas turbine engines and in rocket vehicle turbopumps are described. Also experimental data on self-acting face seals operating under simulated gas turbine conditions are given; these data show the feasibility of operating the seal at conditions of 345 newtons per square centimeter (500 psi) and 152 meters per second (500 ft/sec) sliding speed.

Radial lip seals, thermal aspects

NARCIS (Netherlands)

Stakenborg, M.J.L.; van Ostaijen, R.A.J.; Dowson, D.

1989-01-01

In this paper the influence of temperature on tne seal-snarc contact is studied, using coupled temperature-stress FEH analysis. A thermal network model is used to calculate the seal-shaft contact temperature for steady-state and transient conditions. Contact temperatures were measured under the seal

Airfoil seal system for gas turbine engine

Science.gov (United States)

None, None

2013-06-25

A turbine airfoil seal system of a turbine engine having a seal base with a plurality of seal strips extending therefrom for sealing gaps between rotational airfoils and adjacent stationary components. The seal strips may overlap each other and may be generally aligned with each other. The seal strips may flex during operation to further reduce the gap between the rotational airfoils and adjacent stationary components.

Surface sealing systems for dumps and old waste sites. Oberflaechenabdichtungssysteme fuer Deponien und Altlasten

Energy Technology Data Exchange (ETDEWEB)

Egloffstein, T [ed.; ICP Ingenieurgesellschaft Prof. Czurda und Partner mbH, Karlsruhe (Germany); Burkhardt, G [ed.; ICP Ingenieurgesellschaft Prof. Czurda und Partner mbH, Karlsruhe (Germany)

1994-01-01

The primary task of surface lining is to prevent rainwater from seeping into the wastes deposited below the surface. Its function is therefore to seal the surface. Above the sealing layer there is a drainage system; if large amount of gas are generated (domestic wastes) the gas is channeled through a gas drainage layer. The top layer of the system serves as recultivation horizon for plants. The functions of the liner are: - sealing against precipitating water; - channeling off gas or - seepage water; - plant site. (orig./EF)

A study on the dynamic characteristics of pump seal, 2

International Nuclear Information System (INIS)

Yang, Bosuk; Iwatsubo, Takuzo; Kawai, Ryoji

1984-01-01

From the viewpoint of the rate of plant operation, the vibration problems of pumps have been resolved. Owing to the trend toward high speed and large capacity, the flow of liquid films in the bearings and seals of pumps changed from laminar to turbulent flow, and also the effect of the inertia force of liquid films arose, the dynamic characteristics of high pressure non-contact seals due to fluid force have become to exert important effect on the vibration of pump shafts. In this research, the authors analyzed the dynamic characteristics of a seal due to fluid force when the parallel grooves with rectangular sectional form are made on the circumference of a journal. The equations of motion and the method of analysis, and the example of numerical calculation are reported. For determining the fluid force in a seal when parallel grooves exist, the method of dividing the seal into rands and grooves, determining the fluid force on a rand and in a groove successively for each stage, and summing all up is shown. The compound damping coefficient, added mass coefficient, compound spring coefficient, spring coefficient and damping coefficient were affected by the length of groove part and the Reynolds number in circumferential and axial directions. (Kako, I.)

Analysis on the Viscous Pumping in a Magnetic Fluid Seal Under a Rotating Load and the Seal Design

OpenAIRE

長屋, 幸助; 大沼, 浩身; 佐藤, 淳

1990-01-01

This paper discusses effects of viscous pumping in a magnetic fluid seal under a rotating load. The Reynolds equation was presented for the seal based on magnetic fluid mechanics, and the expressions for obtaining pressures in the seal, eccentricities of the rotating shaft due to the viscous pumping and seal pressures were given. Numerical Calculations were carried out for some sample problems, and the effect of magnetic flux densities on the pressure in the seal and the seal pressures were c...

Albinistic common seals (Phoca vitulina) and melanistic grey seals (Halichoerus grypus) rehabilitated in the Netherlands

NARCIS (Netherlands)

Osinga, Nynke; 't Hart, Pieter; Vader, Pieter C. van Voorst

2010-01-01

The Seal Rehabilitation and Research Centre (SRRC) in Pieterburen, The Netherlands, rehabilitates seals from the waters of the Wadden Sea, North Sea and Southwest Delta area. Incidental observations of albinism and melanism in common and grey seals are known from countries surrounding the North Sea.

Enhanced sealing project: monitoring the THM response of a full-scale shaft seal

Energy Technology Data Exchange (ETDEWEB)

Dixon, D.A.; Martino, J.B.; Holowick, B.; Priyanto, D. [Atomic Energy of Canada Limited, Pinawa, MB (Canada)

2011-07-01

Closure of the subsurface facilities at Atomic Energy of Canada Limited's (AECL) Underground Research Laboratory (URL) was completed in 2010 with installation of a concrete surface cap. Additionally, as part of decommissioning, seals were installed at the penetration of the shafts through the major hydro-geological feature known as Fracture Zone 2 (FZ2). The seal construction was funded by Natural Resources Canada (NRCan) under the Nuclear Legacy Liabilities Program (NLLP). The shaft seals at the URL were based on the composite seal concept developed for application in a deep geological repository for disposal of used nuclear fuel. The access shaft seal consists of two 3-m thick concrete segments that rigidly confine a 6-m long section of swelling clay-based material (40% bentonite clay - 60% sand by dry mass). Monitoring of the regional groundwater recovery following flooding of the lower shaft is a closure requirement and was included in the design. It was widely recognized that the installation of the seals at the URL represented a unique opportunity to monitor the evolution of the type of seal that might be installed in an actual repository but the NLLP mandate did not include any monitoring of shaft seal evolution. As a result the Enhanced Sealing Project (ESP) partnership composed of NWMO, Posiva, SKB and ANDRA was established and a set of 68 instruments (containing 100 sensors) were installed to monitor the evolution of the seal. In the first year of operation sensors have monitored the following parameters in the ESP: thermal evolution and strain of the concrete components, thermal, hydraulic and mechanical changes in the clay component and its contacts with the rock and concrete confinement. Additionally, monitoring of the near-field and regional groundwater evolution has been undertaken. Monitoring of the short-term thermal-mechanical evolution of the concrete components was successfully accomplished and only a small temperature rise occurred due to

Enhanced sealing project: monitoring the THM response of a full-scale shaft seal

International Nuclear Information System (INIS)

Dixon, D.A.; Martino, J.B.; Holowick, B.; Priyanto, D.

2011-01-01

Closure of the subsurface facilities at Atomic Energy of Canada Limited's (AECL) Underground Research Laboratory (URL) was completed in 2010 with installation of a concrete surface cap. Additionally, as part of decommissioning, seals were installed at the penetration of the shafts through the major hydro-geological feature known as Fracture Zone 2 (FZ2). The seal construction was funded by Natural Resources Canada (NRCan) under the Nuclear Legacy Liabilities Program (NLLP). The shaft seals at the URL were based on the composite seal concept developed for application in a deep geological repository for disposal of used nuclear fuel. The access shaft seal consists of two 3-m thick concrete segments that rigidly confine a 6-m long section of swelling clay-based material (40% bentonite clay - 60% sand by dry mass). Monitoring of the regional groundwater recovery following flooding of the lower shaft is a closure requirement and was included in the design. It was widely recognized that the installation of the seals at the URL represented a unique opportunity to monitor the evolution of the type of seal that might be installed in an actual repository but the NLLP mandate did not include any monitoring of shaft seal evolution. As a result the Enhanced Sealing Project (ESP) partnership composed of NWMO, Posiva, SKB and ANDRA was established and a set of 68 instruments (containing 100 sensors) were installed to monitor the evolution of the seal. In the first year of operation sensors have monitored the following parameters in the ESP: thermal evolution and strain of the concrete components, thermal, hydraulic and mechanical changes in the clay component and its contacts with the rock and concrete confinement. Additionally, monitoring of the near-field and regional groundwater evolution has been undertaken. Monitoring of the short-term thermal-mechanical evolution of the concrete components was successfully accomplished and only a small temperature rise occurred due to

Status of the harbour seal (Phoca vitulina in Southern Scandinavia

Directory of Open Access Journals (Sweden)

Morten Tange Olsen

2013-09-01

Full Text Available The harbour seal population in Southern Scandinavia has experienced repeated declines caused by hunting and epizootics. These events have shaped the current distribution and abundance of the population. This paper assesses the current status of the population. We estimate trends in abundance of harbour seals from long term survey data, compare these with historic trends inferred from previously published material, and discuss past and potential threats to the harbour seal population of Southern Scandinavia. It is evident that harbour seals have disappeared from haulout areas along the Danish shores of Kattegat and in the westernmost part of the Baltic Sea, where they were previously numerous. In the 1920-30s, when abundance was at its lowest, the population is estimated to have been only a fraction of its original size. Following 30 years of protection the population is currently approaching historic abundance and might have reached the carrying capacity in some areas. Further development depends largely on effects of future epizootics, anthropogenic disturbance, and availability of suitable haulout sites.

19 CFR 113.25 - Seals.

Science.gov (United States)

2010-04-01

... signatures of principal and surety, if individuals, and the corporate seal shall be affixed close to the... law of the state in which executed. However, when the charter or governing statute of a corporation requires its acts to be evidenced by its corporate seal, such seal is required. ...

Design study of shaft face seal with self-acting lift augmentation. 4: Force balance

Science.gov (United States)

Ludwig, L. P.; Zuk, J.; Johnson, R. L.

1972-01-01

A method for predicting the operating film thickness of self-acting seals is described. The analysis considers a 16.76-cm mean diameter seal that is typical of large gas turbines for aircraft. Four design points were selected to cover a wide range of operation for advanced engines. This operating range covered sliding speeds of 61 to 153 m/sec, sealed pressures of 45 to 217 N/sq cm abs, and gas temperatures of 311 to 977 K. The force balance analysis revealed that the seal operated without contact over the operating range with gas film thicknesses ranging between 0.00046 to 0.00119 cm, and with gas leakage rates between 0.01 to 0.39 scmm.

Spatial Overlap of Grey Seals and Fisheries in Irish Waters, Some New Insights Using Telemetry Technology and VMS.

Directory of Open Access Journals (Sweden)

M Cronin

Full Text Available Seals and humans often target the same food resource, leading to competition. This is of mounting concern with fish stocks in global decline. Grey seals were tracked from southeast Ireland, an area of mixed demersal and pelagic fisheries, and overlap with fisheries on the Celtic Shelf and Irish Sea was assessed. Overall, there was low overlap between the tagged seals and fisheries. However, when we separate active (e.g. trawls and passive gear (e.g. nets, lines fisheries, a different picture emerged. Overlap with active fisheries was no different from that expected under a random distribution, but overlap with passive fisheries was significantly higher. This suggests that grey seals may be targeting the same areas as passive fisheries and/or specifically targeting passive gear. There was variation in foraging areas between individual seals suggesting habitat partitioning to reduce intra-specific competition or potential individual specialisation in foraging behaviour. Our findings support other recent assertions that seal/fisheries interactions in Irish waters are an issue in inshore passive fisheries, most likely at the operational and individual level. This suggests that seal population management measures would be unjustifiable, and mitigation is best focused on minimizing interactions at nets.

The numbers of ringed seals (Phoca hispida in Baffin Bay and associated waters

Directory of Open Access Journals (Sweden)

Michael C S Kingsley

1998-06-01

Full Text Available The size of the population of ringed seals (Phoca hispida inhabiting Baffin Bay and associated waters was estimated by two methods. An approximate model of the energetics of the polar bear (Ursus maritimus estimated an energetic need of about 16,000 MJ/bear per year. Modelled estimates of the energetic yield of a ringed seal population showed that a stable standing population of 140-170 ringed seals per bear would be needed to provide that much energy, assuming that all mortalities were due to polar bear predation. This result was sensitive to assumptions about the Field Metabolic Rate (FMR of the bears and the energetic yield of individual ringed seals, but less sensitive to assumptions about relative incidence of predation on different age classes of seal or the age structure of the polar bear population. Estimated sizes of polar bear populations in Baffin Bay and associated waters (total about 4,025, and of the standing population needed to support an estimated hunter kill of 100,000 yielded a population estimate of, very roughly, 1.2 million ringed seals. Estimates of ice areas and of the density of hauled out seals from aerial surveys were used to generate another approximate figure for the ringed seal population, which was about the same. The density of seals in the pack-ice area of Baffin Bay, which is imperfectly known, has a large influence on the latter estimate.

A simplified time-dependent recovery model as applied to RCP seal LOCAs

International Nuclear Information System (INIS)

Kohut, P.; Bozoki, G.; Fitzpatrick, R.

1991-01-01

In Westinghouse-designed reactors, the reactor coolant pump (RCP) seals constantly require a modest amount of cooling. This cooling function depends on the service water (SW) system. Upon the loss of the cooling function due to the unavailability of the SW, component cooling water system or electrical power (station blackout), the RCP seals may degrade, resulting in a loss-of-coolant accident (LOCA). Recent studies indicate that the frequency of the loss of SW initiating events is higher than previously thought. This change significantly increases the core damage frequency contribution from RCP seal failure. The most critical/dominant element in the loss of SW events was found to be the SW-induced RCP seal failure. For these potential accident scenarios, there are large uncertainties regarding the actual frequency of RCP seal LOCA, the resulting leakage rate, and time-dependent behavior. The roles of various recovery options based on the time evolution of the seal LOCA have been identified and taken into account in recent NUREG-1150 probabilistic risk assessment PRA analyses. In this paper, a consistent time-dependent recovery model is described that takes into account the effects of various recovery actions based on explicit considerations given to a spectrum of time- and flow-rate dependencies. The model represents a simplified approach but is especially useful when extensive seal leak rate and core uncovery information is unavailable

Managing large classes in developing countries | Asodike | Global ...

African Journals Online (AJOL)

This is in line with the global initiative for universal basic education coupled with the rapid population growth and awareness that a literate population is more productive than an illiterate one. Experience has shown that large classes or overcrowded classrooms affect the quality of education delivered in the school system.

Upgrading primary heat transport pump seals

International Nuclear Information System (INIS)

Graham, T.; Metcalfe, R.; Rhodes, D.; McInnes, D.

1995-01-01

Changes in the operating environment at the Bruce-A Nuclear Generating Station created the need for an upgraded Primary Heat Transport Pump (PHTP) seal. In particular, the requirement for low pressure running during more frequent start-ups exposed a weakness of the CAN2 seal and reduced its reliability. The primary concern at Bruce-A was the rotation of the CAN2 No. 2 stators in their holders. The introduction of low pressure running exacerbated this problem, giving rapid wear of the stator back face, overheating, and thermocracking. In addition, the resulting increase in friction between the stator and its holder increased stationary-side hysteresis and thereby changed the seal characteristic to the point where interseal pressure oscillations became prevalent. The resultant increased hysteresis also led to hard rubbing of the seal faces during temperature transients. An upgraded seal was required for improved reliability to avoid forced outages and to reduce maintenance costs. This paper describes this upgraded 'replacement seal' and its performance history. In spite of the 'teething' problems detailed in this paper, there have been no forced outages due to the replacement seal, and in the words of a seal maintenance worker at Bruce-A, 'it allows me to go home and sleep at night instead of worrying about seal failures.' (author)

Collaboration and Commitment to Sealed Source Safety, Security, and Disposition - 13627

International Nuclear Information System (INIS)

Jennison, Meaghan; Martin, David W.

2013-01-01

EnergySolutions, the Division of Radiation Control at the Utah Department of Environmental Quality (UDEQ), the Conference of Radiation Control Program Directors (CRCPD), and the Department of Energy's Global Threat Reduction Initiative (GTRI) are collaborating on a truly innovative effort to expand opportunities for cost-effective sealed source disposal. These entities have developed a first-of-its-kind initiative to dispose of certain sealed sources at the EnergySolutions disposal facility near Clive, Utah, which normally cannot accept sealed sources of any type. This creative and collaborative effort to improve radiation health, safety, and security exemplifies the spirit and commitment represented by the Richard S. Hodes, M.D. Honor Lecture Award, which is presented annually at the Waste Management Symposia by the Southeast Compact Commission to encourage environmental professionals and political leaders to develop innovative approaches to waste management in the United States. The participants in the collaborative initiative are honored to receive special recognition for their efforts thus far. They also recognize that the hard work remains to be done. (authors)

Advanced High Temperature Structural Seals

Science.gov (United States)

Newquist, Charles W.; Verzemnieks, Juris; Keller, Peter C.; Rorabaugh, Michael; Shorey, Mark

2002-10-01

This program addresses the development of high temperature structural seals for control surfaces for a new generation of small reusable launch vehicles. Successful development will contribute significantly to the mission goal of reducing launch cost for small, 200 to 300 pound payloads. Development of high temperature seals is mission enabling. For instance, ineffective control surface seals can result in high temperature (3100 F) flows in the elevon area exceeding structural material limits. Longer sealing life will allow use for many missions before replacement, contributing to the reduction of hardware, operation and launch costs.

Upgrading inflatable door seals

International Nuclear Information System (INIS)

Sykes, T.M.; Metcalfe, R.; Welch, L.A.; Josefowich, J.M.

1997-01-01

Inflatable door seals are used for airlocks in CANDU stations. They have been a significant source of unreliability and maintenance cost. A program is underway to improve their performance and reliability, backed by environmental qualification testing. Only commercial products and suppliers existed in 1993. For historical reasons, these 'existing products' did not use the most durable material then available. In hindsight, neither had they been adapted nor optimized to combat conditions often experienced in the plants-sagging doors, damaged sealing surfaces, and many thousands of openings and closings per year. Initial attempts to involve the two existing suppliers in efforts to upgrade these seals were unsuccessful. Another suitable supplier had therefore to be found, and a 'new,' COG-owned seal developed; this was completed in 1997. This paper summarizes its testing, along with that of the two existing products. Resistance to aging has been improved significantly. Testing has shown that an accident can be safely withstood after 10 years of service or 40,000 openings-closings, whichever comes first. AECL's Fluid Sealing Technology Unit (FSTU) has invested in the special moulds, test fixtures and other necessary tooling and documentation required to begin commercial manufacture of this new quality product. Accordingly, as with FSTU's other nuclear products such as pump seals, the long-term supply of door seals to CANDU plants is now protected from many external uncertainties-e.g., commercial products being discontinued, materials being changed, companies going out of business. Manufacturing to AECL's detailed specifications is being subcontracted to the new supplier. FSTU is performing the quality surveillance, inspection, testing, and customer service activities concomitant with direct responsibility for supply to the plants. (author)

Fiber Optic Safeguards Sealing System

Science.gov (United States)

1978-01-01

8217 or trade names does not constitute an official indorsement or approval of the use thereof. Destroy this report when it is no longer needed. Do not...an intergrity check of a seal than to photograph the seal’s fingerprints and to match positive/negative overlays. The seal identification time and

Seal carrion is a predictable resource for coastal ecosystems

Science.gov (United States)

Quaggiotto, Maria-Martina; Barton, Philip S.; Morris, Christopher D.; Moss, Simon E. W.; Pomeroy, Patrick P.; McCafferty, Dominic J.; Bailey, David M.

2018-04-01

The timing, magnitude, and spatial distribution of resource inputs can have large effects on dependent organisms. Few studies have examined the predictability of such resources and no standard ecological measure of predictability exists. We examined the potential predictability of carrion resources provided by one of the UK's largest grey seal (Halichoerus grypus) colonies, on the Isle of May, Scotland. We used aerial (11 years) and ground surveys (3 years) to quantify the variability in time, space, quantity (kg), and quality (MJ) of seal carrion during the seal pupping season. We then compared the potential predictability of seal carrion to other periodic changes in food availability in nature. An average of 6893 kg of carrion •yr-1 corresponding to 110.5 × 103 MJ yr-1 was released for potential scavengers as placentae and dead animals. A fifth of the total biomass from dead seals was consumed by the end of the pupping season, mostly by avian scavengers. The spatial distribution of carcasses was similar across years, and 28% of the area containing >10 carcasses ha-1 was shared among all years. Relative standard errors (RSE) in space, time, quantity, and quality of carrion were all below 34%. This is similar to other allochthonous-dependent ecosystems, such as those affected by migratory salmon, and indicates high predictability of seal carrion as a resource. Our study illustrates how to quantify predictability in carrion, which is of general relevance to ecosystems that are dependent on this resource. We also highlight the importance of carrion to marine coastal ecosystems, where it sustains avian scavengers thus affecting ecosystem structure and function.

Turbine Seal Research at NASA GRC

Science.gov (United States)

Proctor, Margaret P.; Steinetz, Bruce M.; Delgado, Irebert R.; Hendricks, Robert C.

2011-01-01

Low-leakage, long-life turbomachinery seals are important to both Space and Aeronautics Missions. (1) Increased payload capability (2) Decreased specific fuel consumption and emissions (3) Decreased direct operating costs. NASA GRC has a history of significant accomplishments and collaboration with industry and academia in seals research. NASA's unique, state-of-the-art High Temperature, High Speed Turbine Seal Test Facility is an asset to the U.S. Engine / Seal Community. Current focus is on developing experimentally validated compliant, non-contacting, high temperature seal designs, analysis, and design methodologies to enable commercialization.

Enhanced sealing project (ESP): design, construction and monitoring of a full-scale shaft seal

International Nuclear Information System (INIS)

Dixon, D.; Martino, J.; Kim, C.S.; Holowick, B.; Kwong, G.; Jonsson, E.; Palonen, E.; DeCombarieu, M.

2010-01-01

Document available in extended abstract form only. The Enhanced Sealing Project (ESP) consists of instrumenting and monitoring a full-scale shaft seal installed to permanently close the access shaft for Atomic Energy of Canada Limited's (AECL's) Underground Research Laboratory (URL) at the intersection of an ancient low dipping thrust fault. The URL was built to provide a facility where concepts for long-term management of Canada's nuclear fuel waste in a deep geological repository could be studied. Operated since the early 1980's, this facility provided much of the technical information used in developing the deep geological repository concept submitted by AECL to the Government of Canada in 1994 and continued to provide valuable technical data after that submission. In 2003, a decision was made to discontinue operation of the URL and ultimately decommission and permanently close the underground portion of this facility. As part of the Nuclear Legacy Liability Program (NLLP) being funded by Natural Resources Canada (NRCan), facilities including the URL that are no longer part of AECL's mandate or operations are being decommissioned. Included in this work is the installation of seals at the intersection of the access shaft and ventilation raise with a deep fracture zone in order to limit the potential for mixing of deeper saline and shallower less saline groundwater. The funding available from NRCan was limited to the seal installation, with no mandate to provide any more than basic hydrological monitoring of the rock mass at a considerable distance from these seals, and so the opportunity to monitor a full-scale shaft seal similar to one for a deep geological repository would have been lost. The ESP arose from the recognition by a number of organizations that the URL closure presented a unique opportunity to monitor the evolution of a full-scale repository-type shaft seal in a very well-characterized and otherwise undisturbed rock mass. As

Sealed can of spent fuel

International Nuclear Information System (INIS)

Suzuki, Yasuyuki.

1976-01-01

Object: To provide a seal plug cover with a gripping portion fitted to a canning machine and a gripping portion fitted to a gripper of the same configuration as a fuel body for handling the fuel body so as to facilitate the handling work. Structure: A sealed can comprises a vessel and a seal plug cover, said cover being substantially in the form of a bottomed cylinder, which is slipped on the vessel and air-tightly secured by a fastening bolt between it and a flange. The spent fuel body is received into the vessel together with coolant during the step of canning operation. Said seal plug cover has two gripping portions, one for opening and closing the plug cover of the canning machine as an exclusive use member, the other being in the form of a hook-shaped peripheral groove, whereby the gripping portions may be effectively used using the same gripper when the spent fuel body is transported while being received in the sealed can or when the fuel body is removed from the sealed can. (Kawakami, Y.)

Characterization and packaging of disused sealed radioactive sources

International Nuclear Information System (INIS)

Aguilar, S.L.

2013-01-01

In Bolivia are generated disused sealed sources and radioactive waste resulting from the use of radioactive materials in industrial, research and medicine. The last includes the diagnosis and treatment. Whereas exposure to ionizing radiation is a potential hazard to personnel who applies it, to those who benefit from its use or for the community at large, it is necessary to control the activities in this field. The Instituto Boliviano de Ciencia y Tecnologia Nuclear - IBTEN is working on a regional project from International Atomic Energy Agency - IAEA, RLA/09/062 Project - TSA 4, Strengthening the National Infrastructure and Regulatory Framework for the Safe Management of Radioactive waste in Latin America. This Project has strengthened the regulatory framework regarding the safe management of radioactive waste. The aim of this work was focused primarily on the security aspects in the safe management of disused sealed sources. The tasks are listed below: 1. Characterization of disused sealed sources 2. Preparation for transport to temporary storage 3. Control of all disused radioactive sources. (author)

On the CFT Operator Spectrum at Large Global Charge

CERN Multimedia

CERN. Geneva

2015-01-01

We calculate the anomalous dimensions of operators with large global charge J in certain strongly coupled conformal field theories in three dimensions, such as the O(2) model and the supersymmetric fixed point with a single chiral superfield and a W = Φ3 superpotential. Working in a 1/J expansion, we find that the large-J sector of both examples is controlled by a conformally invariant effective Lagrangian for a Goldstone boson of the global symmetry. For both these theories, we find that the lowest state with charge J is always a scalar operator whose dimension ΔJ satisfies the sum rule J2 ΔJ - ( J2/2+ J/4 + 3/16) ΔJ-1 - ( J2/2 - J/4 + 3/16) ΔJ+1 = 0.04067 up to corrections that vanish at large J. The spectrum of low-lying excited states is also calculable explicitly: For example, the second-lowest primary operator has spin two and dimension ΔJ + √3. In the supersymmetric case, the dimensions of all half-integer-sp...

Seal-die of Prince Lazar from Rudnik

Directory of Open Access Journals (Sweden)

Radičević Dejan

2016-01-01

Full Text Available The medieval settlement on the Rudnik Mountain was established, most probably, in the final decades of the 13th century. Soon it evolved into one of the best known mining and commercial centres in the Serbian state and reached its peak during the 14th and in the first half of the 15th century. The importance of Rudnik in the medieval period is confirmed by numerous material traces in the field. The most important discoveries in the course of archaeological investigations carried out since 2009 have been encountered in the area called Drenje, not far from the centre of the town of Rudnik (figs. 1, 2.Three churches (two Orthodox and one Roman Catholic, as well as many profane structures dated to the time of a thriving medieval Rudnik have so far been discovered. It indicates that in that area are the remains of the main settlement and the medieval market place of Rudnik, known from written sources. Among other structures at the site of Drenje, in the garden of S. Markovi}, the remains of rather a large building consisting, according to present data, of at least two rooms, have been investigated during the past three years (fig. 3. Important for dating the structure is a coin of the Hungarian king Sigismund of Luxembourg (1387-1437, discovered on the floor. Traces of an earlier phase of life were encountered under the structure (fig. 5. Coins have been found in two earlier pits. In the soil inside pit 11 a coin of the Hungarian king Charles Robert (1308-1342 was found, while in the top level of pit 2 a coin attributed to Prince Lazar (around 1370-1389 was found. Also from pit 2 came a, so far, unique archaeological find in our territory. It has been explained as a seal-die used for producing seals (fig, 7, 8. The representation in the central field and the contents of the inscription bear witness to the fact that the seal-die belonged to Prince Lazar. A helmet with bull horns engraved on the front side is understood to be the coat of arms of Prince

Molecular Indicators of Chronic Stress in a Model Pinniped - The Northern Elephant Seal

Science.gov (United States)

2015-09-30

Pinniped - The Northern Elephant Seal Cory Champagne , Jane Kyudyakov, & Dorian Houser National Marine Mammal Foundation 2240 Shelter Island Dr, Suite...in studies of stress and its impacts ( Champagne et al, 2012). Measurements will be conducted in juvenile elephant seals that reliably haul out each...their large adipose stores) and a reduced amino acid release (potentially resulting from a protein sparing adaptation during fasting; Champagne et

Insecurity of imperfect quantum bit seal

International Nuclear Information System (INIS)

Chau, H.F.

2006-01-01

Quantum bit seal is a way to encode a classical bit quantum mechanically so that everyone can obtain non-zero information on the value of the bit. Moreover, such an attempt should have a high chance of being detected by an authorized verifier. Surely, a reader looks for a way to get the maximum amount of information on the sealed bit and at the same time to minimize her chance of being caught. And a verifier picks a sealing scheme that maximizes his chance of detecting any measurement of the sealed bit. Here, I report a strategy that passes all measurement detection procedures at least half of the time for all quantum bit sealing schemes. This strategy also minimizes a reader's chance of being caught under a certain scheme. In this way, I extend the result of Bechmann-Pasquinucci et al. by proving that quantum seal is insecure in the case of imperfect sealed bit recovery

Ultrasonic dip seal maintenance system

International Nuclear Information System (INIS)

Poindexter, A.M.; Ricks, H.E.

1978-01-01

Disclosed is a system for removing impurities from the surfaces of liquid dip seals and for wetting the metal surfaces of liquid dip seals in nuclear components. The system comprises an ultrasonic transducer that transmits ultrasonic vibrations along an ultrasonic probe to the metal and liquid surfaces of the dip seal thereby loosening and removing those impurities

Reusable tamper-indicating security seal

International Nuclear Information System (INIS)

Ryan, M.J.

1981-01-01

A reusable tamper-indicating mechanical security seal for use in safeguarding nuclear material has been developed. The high-security seal displays an unpredictable, randomly selected, five-digit code each time it is used. This five digit code serves the same purpose that the serial number does for conventional non-reusable seals - a unique identifier for each use or application. The newly developed reusable seal is completely enclosed within a seamless, tamper-indicating, plastic jacket. The jacket is designed to reveal any attempts to penetrate, section or to chemically remove and replace with a counterfeit for surreptitious purposes

Actively controlled shaft seals for aerospace applications

Science.gov (United States)

Salant, Richard F.

1995-07-01

This study experimentally investigates an actively controlled mechanical seal for aerospace applications. The seal of interest is a gas seal, which is considerably more compact than previous actively controlled mechanical seals that were developed for industrial use. In a mechanical seal, the radial convergence of the seal interface has a primary effect on the film thickness. Active control of the film thickness is established by controlling the radial convergence of the seal interface with a piezoelectric actuator. An actively controlled mechanical seal was initially designed and evaluated using a mathematical model. Based on these results, a seal was fabricated and tested under laboratory conditions. The seal was tested with both helium and air, at rotational speeds up to 3770 rad/sec, and at sealed pressures as high as 1.48 x 10(exp 6) Pa. The seal was operated with both manual control and with a closed-loop control system that used either the leakage rate or face temperature as the feedback. The output of the controller was the voltage applied to the piezoelectric actuator. The seal operated successfully for both short term tests (less than one hour) and for longer term tests (four hours) with a closed-loop control system. The leakage rates were typically 5-15 slm (standard liters per minute), and the face temperatures were generally maintained below 100C. When leakage rate was used as the feedback signal, the setpoint leakage rate was typically maintained within 1 slm. However, larger deviations occurred during sudden changes in sealed pressure. When face temperature was used as the feedback signal, the setpoint face temperature was generally maintained within 3 C, with larger deviations occurring when the sealed pressure changes suddenly. the experimental results were compared to the predictions from the mathematical model. The model was successful in predicting the trends in leakage rate that occurred as the balance ratio and sealed pressure changed

Bite injuries of grey seals (Halichoerus grypus) on harbour porpoises (Phocoena phocoena).

Science.gov (United States)

Jauniaux, Thierry; Garigliany, Mutien-Marie; Loos, Pauline; Bourgain, Jean-Luc; Bouveroux, Thibaut; Coignoul, Freddy; Haelters, Jan; Karpouzopoulos, Jacky; Pezeril, Sylvain; Desmecht, Daniel

2014-01-01

Bite-like skin lesions on harbour porpoises (Phocoena phocoena) have been suspected to be caused by grey seals (Halichoerus grypus), and a few field observations have been reported. Bite-like skin lesions observed on stranded animals were characterized by two main components: large flaps of loose or missing skin and blubber with frayed edges and puncture lesions. Definitive demonstration of predation by a grey seal was not reported so far in those stranded animals. In this study, five stranded porpoises with bite-like skin lesions were swabbed for genetic investigations. In addition, the head of a recently dead grey seal was used to mimic bite-like skin injuries on a porpoise carcass. Subsequently, the artificial skin injuries were swabbed, along with the gum of the seal used for inflicting them (positive controls). Total DNA was extracted from the swabs and was used to retrieve a fragment of mitochondrial DNA by PCR. Primers were designed to amplify a specific stretch of mitochondrial DNA known to differ between grey seals and porpoises. The amplicon targeted was successfully amplified from the positive control and from two of the stranded porpoises, and grey seal-specific mitochondrial DNA was retrieved from all those samples. We conclude that (1) it is possible to detect grey seal DNA from dead porpoises even after several days in seawater and (2) bite-like skin lesions found on dead porpoises definitively result from grey seals attacks. The attacks are most likely linked with predation although, in a number of cases, scavenging and aggressive behaviour cannot be excluded.

Pool gateway seal

International Nuclear Information System (INIS)

Starr, J.A.; Steinert, L.A.

1983-01-01

A device for sealing a gateway between interconnectable pools in a nuclear facility comprising a frame supporting a liquid impermeable sheet positioned in a u-shaped gateway between the pools. An inflatable tube carried in a channel in the periphery of the frame and adjoining the gateway provides a seal therebetween when inflated. A restraining arrangement on the bottom edge of the frame is releasably engagable with an adjacent portion of the gateway to restrict the movement of the frame in the u-shaped gateway upon inflation of the tube, thereby enhancing the seal. The impermeable sheet is formed of an elastomer and thus is conformable to a liquid permeable supportive wall upon application of liquid pressure to the side of the sheet opposite the wall

Development and high temperature sealing performance study of double sealing flange

International Nuclear Information System (INIS)

Zhang Qinhua; Fu Yuan; Xie Leidong; Li Zhong; Tang Zhongfeng

2013-01-01

Background: Flange is an important component used in the connection between pipes or between pipe and equipment. It is widely used in mechanical industry, petrochemical industry and nuclear industry. Ordinary flange could be oxidized oi corroded under high temperature and strong corrosion condition, which leads to flange's failure. Purpose: The aim is to design and validate the double sealing flange which could be used in high temperature and strong corrosion condition stably and supplied as a reliable detachable connection for petrochemical industry and nuclear industry under high temperature and strong corrosion environment. Methods: New flange is designed using flexible graphite spiral wound gaskets and C style metal ring double sealing structure. The unique protection gas design ensures the graphite spiral wound gasket used in high temperature reliably. Test bed is built to verify the stability of the flange. Results: Pressure reducing of graphite spiral wound gasket is only 0.01 MPa at 750℃, 0.7 MPa for 43 h, there is not obvious oxidation phenomenon at the same time. The leakage rate of metal C sealing ring is 11.51×10 -4 atm cc/s, and the metal C ring sealing's performance meets the engineering requirements. Conclusion: The leakage rate of double sealing flange is almost zero under 0.7 MPa at 750℃, which meets the engineering requirements. It avoids oxidizing at high temperature and corroding under strong corrosion condition. (authors)

Proposed sealing field tests for a potential high-level radioactive waste repository in unsaturated tuff

International Nuclear Information System (INIS)

Fernandez, J.A.; Case, J.B.; Tyburski, J.

1992-01-01

This paper contains a general description of the field tests proposed for the Yucca Mountain Site Characterization Project repository sealing program. The tests are intended to resolve various performance and emplacement concerns associated with sealing components. Ten discrete tests are proposed to address these concerns. These tests are divided into two categories -- simple and complex tests. The simple tests are: the small-scale in situ tests: the intermediate-scale borehole seal tests; the fracture grouting tests; the surface backfill tests; and the grouted rock mass tests. The complex tests are the seepage control tests; in situ backfill tests; in situ bulkhead tests; large-scale shaft seal tests; and remote borehole seal tests. These tests are proposed to be performed in welded and nonwelded tuff environments. The final selection of sealing tests will depend on the nature of the geologic and hydrologic conditions encountered during the development of the exploratory studies facility. Some tests may be performed before license application and some after license application

Steam Turbine Flow Path Seals (a Review)

Science.gov (United States)

Neuimin, V. M.

2018-03-01

Various types of shroud, diaphragm, and end seals preventing idle leak of working steam are installed in the flow paths of steam turbine cylinders for improving their efficiency. Widely known labyrinth seals are most extensively used in the Russian turbine construction industry. The category of labyrinth seals also includes seals with honeycomb inserts. The developers of seals with honeycomb inserts state that the use of such seals makes it possible to achieve certain gain due to smaller leaks of working fluid and more reliable operation of the system under the conditions in which the rotor rotating parts may rub against the stator elements. However, a positive effect can only be achieved if the optimal design parameters of the honeycomb structure are fulfilled with due regard to the specific features of its manufacturing technology and provided that this structure is applied in a goal-seeking manner in the seals of steam and gas turbines and compressors without degrading their vibration stability. Calculated and preliminary assessments made by experts testify that the replacement of conventional labyrinth seals by seals with honeycomb inserts alone, due to which the radial gaps in the shroud seal can be decreased from 1.5 to 0.5 mm, allows the turbine cylinder efficiency to be increased at the initial stage by approximately 1% with the corresponding gain in the turbine set power output. The use of rectangular-cellular seals may result, according to estimates made by their developers, in a further improvement of turbine efficiency by 0.5-1.0%. The labor input required to fabricate such seals is six to eight times smaller than that to fabricate labyrinth seals with honeycomb inserts. Recent years have seen the turbine construction companies of the United States and Germany advertising the use of abradable (sealing) coatings (borrowed from the gas turbine construction technology) in the turbine designs instead of labyrinth seals. The most efficient performance of

Avoidance of wind farms by harbour seals is limited to pile driving activities.

Science.gov (United States)

Russell, Debbie J F; Hastie, Gordon D; Thompson, David; Janik, Vincent M; Hammond, Philip S; Scott-Hayward, Lindesay A S; Matthiopoulos, Jason; Jones, Esther L; McConnell, Bernie J

2016-12-01

As part of global efforts to reduce dependence on carbon-based energy sources there has been a rapid increase in the installation of renewable energy devices. The installation and operation of these devices can result in conflicts with wildlife. In the marine environment, mammals may avoid wind farms that are under construction or operating. Such avoidance may lead to more time spent travelling or displacement from key habitats. A paucity of data on at-sea movements of marine mammals around wind farms limits our understanding of the nature of their potential impacts.Here, we present the results of a telemetry study on harbour seals Phoca vitulina in The Wash, south-east England, an area where wind farms are being constructed using impact pile driving. We investigated whether seals avoid wind farms during operation, construction in its entirety, or during piling activity. The study was carried out using historical telemetry data collected prior to any wind farm development and telemetry data collected in 2012 during the construction of one wind farm and the operation of another.Within an operational wind farm, there was a close-to-significant increase in seal usage compared to prior to wind farm development. However, the wind farm was at the edge of a large area of increased usage, so the presence of the wind farm was unlikely to be the cause.There was no significant displacement during construction as a whole. However, during piling, seal usage (abundance) was significantly reduced up to 25 km from the piling activity; within 25 km of the centre of the wind farm, there was a 19 to 83% (95% confidence intervals) decrease in usage compared to during breaks in piling, equating to a mean estimated displacement of 440 individuals. This amounts to significant displacement starting from predicted received levels of between 166 and 178 dB re 1 μPa (p-p) . Displacement was limited to piling activity; within 2 h of cessation of pile driving, seals were distributed as

Optimization of the pumping ring in a mechanical seal with an integrated cooler for feed-water pumps

International Nuclear Information System (INIS)

Buchdahl, D.; Martin, R.; Gueret, G.; Blanc, M.

1994-07-01

To simplify maintenance, E.D.F. along with its collaborators undertook the study of mechanical seal with integrated cooler used in feed-water pumps in the nuclear power plants. The cooler, integrated to the pump acts as a thermal barrier as well as a cooler of the mechanical seal. The water circulation in the cooler is assumed by an integrated pumping ring in the rotary part of the mechanical seal, with a matching screw thread in the pumping case. This assembly of mechanical seal/integrated cooler is tested in a test loop at the EDF/DER Laboratory. All working conditions are similar to that at site. Tests with different configurations of the rotor/stator profiles are performed, i.e.; different lengths and types of threading. Hydraulic performances and the global thermal balance of this assembly are studied. Our basic aim during these tests is to optimize the hydraulic performance of the pumping ring so as to best cool the mechanical seal faces. The different results obtained and the conclusions drawn during these tests are presented. (authors). 7 figs., 3 refs

SEAL FOR HIGH SPEED CENTRIFUGE

Science.gov (United States)

Skarstrom, C.W.

1957-12-17

A seal is described for a high speed centrifuge wherein the centrifugal force of rotation acts on the gasket to form a tight seal. The cylindrical rotating bowl of the centrifuge contains a closure member resting on a shoulder in the bowl wall having a lower surface containing bands of gasket material, parallel and adjacent to the cylinder wall. As the centrifuge speed increases, centrifugal force acts on the bands of gasket material forcing them in to a sealing contact against the cylinder wall. This arrangememt forms a simple and effective seal for high speed centrifuges, replacing more costly methods such as welding a closure in place.

Review on utilization and research on harbour seal (Phoca vitulina in Iceland

Directory of Open Access Journals (Sweden)

Erlingur Hauksson

2010-09-01

Full Text Available Harbour seals (Phoca vitulina have been harvested in Iceland since the first settlers arrived in the 9th century. Pups were generally netted, clubbed and harpooned until 1875 when general use of guns for hunting began. Seal-hunting has been traditional amongst the farms legal rights. Seal hunting was an important supplement to other economic resources. Harbour seal skins, salted ordried, were exported and large dataset of catch statistics is available from trading logbooks since the late 19th century. In the early 20th century catch was about 6,000. In the ‘bounty’ period 1982 – 1989, maximum catches were of 4,000 animals with about 350 hunters participated; in 2006 catches were only about 100 animals with 18 hunters. After 1989 the population continued to decline even though catches decreased markedly. Unreported by-catch in fishing gear, hunt for local consumption and shooting of seals swimming in salmon rivers estuaries may have kept the total removal from the stock above sustainable levels. A considerable Icelandic knowledge base had been compiled about the biology of the harbour seal since the late 16th century, with the first written reference in 1588-1589. In the last decades, research on various aspects of its biology and monitoring have been intensified, with focus on abundance, distribution, diet and nematode infestation. The main results show that the Icelandic harbour seal population - has declined annually about 5% in the period 1980-2006, - was most abundant on the NW-coast, - feeds mainly on sand-eels and gadoids, - and was less infected with anisakid nematodes than grey seals. Seal watching, as a low-consumptive indirect utilization, may represent a new economical opportunity if properly regulated.

Abelian scalar theory at large global charge

Energy Technology Data Exchange (ETDEWEB)

Loukas, Orestis [Albert Einstein Center for Fundamental Physics, Institute for Theoretical Physics, University of Bern (Switzerland)

2017-09-15

We elaborate on Abelian complex scalar models, which are dictated by natural actions (all couplings are of order one), at fixed and large global U(1) charge in an arbitrary number of dimensions. The ground state vertical stroke v right angle is coherently constructed by the zero modes and the appearance of a centrifugal potential is quantum mechanically verified. Using the path integral formulation we systematically analyze the quantum fluctuations around vertical stroke v right angle in order to derive an effective action for the Goldstone mode, which becomes perturbatively meaningful when the charge is large. In this regime we explicitly show, by computing the first few loop corrections, that the whole construction is stable against quantum effects, in the sense that any higher derivative couplings to Goldstone's tree-level action are suppressed by appropriate powers of the large charge. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Miniature magnetic fluid seal working in liquid environments

Energy Technology Data Exchange (ETDEWEB)

Mitamura, Yoshinori, E-mail: ymitamura@par.odn.ne.jp [Graduate School of Information Science and Technology, Hokkaido University, Sapporo 060-0814 (Japan); Durst, Christopher A., E-mail: chris@procyrion.com [Procyrion, Inc., Houston, TX 77027 (United States)

2017-06-01

This study was carried out to develop a miniature magnetic fluid (MF) seal working in a liquid environment. The miniature MF seal is intended for use in a catheter blood pump. The requirements for the MF seal included a size of less than Ø4×4.5 mm, shaft diameter of 1 mm, sealing pressure of 200 mmHg, shaft speed of up to 40000 rpm, and life of one month. The miniature MF seal was composed of an NdFeB magnet (Ø4×Ø2×1) sandwiched between two pole pieces (Ø4×Ø1.1×0.5). A shield (Ø4×Ø1.2×1.5) was placed on the pole piece facing the liquid to minimize the influence of pump flow on the MF. The seal was installed on a Ø1 shaft. A seal was formed by injecting MF (Ms: 47.8 kA/m and η: 0.5 Pa·sec) into the gap between the pole pieces and the shaft. Total volume of the MF seal was 44 μL. A sealing pressure of 370 mmHg was obtained at motor speeds of 0-40,000 rpm. The seal remained perfect for 10 days in saline under the condition of a pump flow of 1.5 L/min (The test was terminated in accordance with plans). The seal remained intact after ethylene oxide sterilization during which the seal was exposed to high pressures. In conclusion, the newly developed MF seal will be useful for a catheter pump. - Highlights: • A miniature magnetic fluid seal working in a liquid environment was developed. • The seal can be installed on Ø1 mm shaft and can seal against 370 mmHg at 40000 rpm. • The magnetic fluid seal will be useful for a catheter blood pump.

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

Science.gov (United States)

Dirusso, E.

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.

Seal Apparatus and Methods to Manufacture Thereof

Science.gov (United States)

Richard, James A. (Inventor)

2013-01-01

In some implementations, apparatus and methods are provided through which a dynamic cryogenic seal is manufactured. In some implementations, the seal includes a retainer and a spring-seal assembly, the assembly being comprised of a main spring housing and fluorine-containing polymer seals. In some implementations, either a radial seal, or an axial (or "piston seal") is provided. In some implementations, methods of manufacturing the dynamic cryogenic seal are also provided. In some implementations, the methods include assembling the components while either heated or cooled, taking advantage of thermal expansion and contraction, such that there is a strong interference fit between the components at room temperature. In some implementations, this process ensures that the weaker fluorine-containing polymer seal is forced to expand and contract with the stronger retainer and spring and is under constant preload. In some implementations, the fluorine-containing polymer is therefore fluidized and retained, and can not lift off.

A dynamic analysis of rotary combustion engine seals

Science.gov (United States)

Knoll, J.; Vilmann, C. R.; Schock, H. J.; Stumpf, R. P.

1984-01-01

Real time work cell pressures are incorporated into a dynamic analysis of the gas sealing grid in Rotary Combustion Engines. The analysis which utilizes only first principal concepts accounts for apex seal separation from the crochoidal bore, apex seal shifting between the sides of its restraining channel, and apex seal rotation within the restraining channel. The results predict that apex seals do separate from the trochoidal bore and shift between the sides of their channels. The results also show that these two motions are regularly initiated by a seal rotation. The predicted motion of the apex seals compares favorably with experimental results. Frictional losses associated with the sealing grid are also calculated and compare well with measurements obtained in a similar engine. A comparison of frictional losses when using steel and carbon apex seals has also been made as well as friction losses for single and dual side sealing.

Mechanical seal having a double-tier mating ring

Science.gov (United States)

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.

Development of the seal for nuclear material

International Nuclear Information System (INIS)

Lu Feng; Lu Zhao; Zhao Yonggang; Zhang Qixin; Xiao Xuefu

2000-01-01

Two kinds of double cap metallic seal and an adhesive seal are developed for the purpose of the accounting for and control of nuclear material. Two kinds of double cap metallic seal are made of stainless steel and copper, respectively and the self-locked technique is used. The number and the random pattern are carved out side and in side of a cap, respectively, for the seal. The random pattern carved inside of a cap for seal is taken a picture using numeral camera and memorized in computer. Special software is developed for verification of the random pattern memorized in computer. The adhesive seal is made of special adhesive paper for purpose of security, and a special pattern guarded against falsification is printed on seal paper using ultraviolet fluorescent light technique

Endurance test report of rubber sealing materials for the containment vessel

International Nuclear Information System (INIS)

Yamamoto, R.; Watanabe, K.; Hanashima, K.

2015-01-01

In the event of a nuclear power plant accident such as a core meltdown and a cooling system failure, the containment contains radioactive materials released from the reactor pressure vessel to reduce the activity of the radioactive materials and the effects of radiation in the vicinity of the plant. Since high sealing performance and high pressure resistance are required of the containment, a silicone or EPDM rubber gasket with high heat and radiation resistance is used for the sealing of the sealing boundary of the containment. In recent years, it has been shown that a large amount of steam is released into the containment in the case of a severe accident. Consequently, radiation resistance at high temperature as well as steam resistance is required of the rubber gasket placed at the sealing boundary. However, the steam resistance of silicone rubber is not necessarily as good as that of EPDM rubber. Therefore, it is necessary to evaluate the sealing characteristics of rubber gaskets in such a degrading environment in a severe accident. O. Kato et al. [1] conducted a study on the degradation status of rubber gaskets and their application limits at high temperature. However, few studies have evaluated rubber gaskets in high-temperature radiation and steam environments. In this study, we degraded silicone rubber and EPDM rubber used for the containment in the high-temperature radiation and steam environments expected to occur in a severe accident and evaluated the useful life of the rubber as a sealing material by estimating the change in its performance as a sealing material from the change in permanent compressive strain in the rubber. (author)

Innovation to reality for improved pump seal performance

International Nuclear Information System (INIS)

Wong, W.; Eyvindson, A.; Rhodes, D.B.

2003-01-01

'Full-Text:' The nuclear industry requires reliable pump seals. Extended operating conditions for aging plants (i.e., low pressure starts, pressure and temperature transients) and increasing demands from new plants (larger sizes, higher speeds) are pushing the operating envelope for seals. This means that many seals that were previously considered adequate are now requiring increased attention and care. Operating utilities have taken different approaches to addressing their existing, or emerging, seal problems. Primary concerns include maintenance practices, seal design, and monitoring capabilities, as well as operating conditions, transients, pump and motor design. Success in this area requires ongoing dialogue among the station operators, pump manufacturers and seal designers. Regardless of the design, the basic requirement in CANDU is a reliable seal lifetime exceeding 5 years. This paper describes AECL's efforts to meet this requirement through an ongoing program of research and development in seal technology. Current work includes rigorous testing and evaluation of new seal materials and coatings to maximize seal stability and minimize friction and wear (i.e., pressure/temperature transients produce unpredictable shaft movement that can significantly alter face deflections affecting leak rates and seal stability, and sometimes cause the seal to hang-up and de-stage). Also required is a practical method for on-line monitoring of the condition of the seal, whether it is newly installed or after several years of reliable performance. This provides crucial information for inventory, maintenance and outage planning. While new concepts may look good on paper, it is only after they have been demonstrated under fully representative station operating conditions that they can truly be considered ready for field use. AECL CAN-seals lead the nuclear industry in reliability and seal life. They effectively save operators millions of dollars in outage time and person

The effect of organic matter in clay sealing materials on the performance of a nuclear fuel waste disposal vault

International Nuclear Information System (INIS)

Oscarson, D.W.; Stroes-Gascoyne, S.; Cheung, S.C.H.

1986-12-01

The potential effect of organic matter in clay sealing materials on the performance of a nuclear fuel waste disposal vault was examined. The available data indicate that the engineering properties of clays are not significantly affected by the relatively low levels of organic matter (< 1.2 wt.%) present in the clay sealing materials. Complexing of radionuclides by organic substances that are released from the clay sealing materials or produced by microorganisms will likely inhibit rather than promote radionuclide mobility in the compacted sealing materials because of the relatively large size of organic complexing species. Decreasing the level of organic matter in the clay sealing materials will not eliminate microorganisms, and perhaps not decrease their numbers significantly, because chemolithotrophic microorganisms (microorganisms that utilize inorganic forms of C) will be present in a disposal vault. Furthermore, an examination of the nutrient budget in a disposal vault indicates that N, rather than C, will likely be the limiting nutrient for microbial growth. Finally, there is not suitable, proven method for decreasing the level of organic matter in the large amounts of clay needed to seal a vault. It is concluded that the organic matter present in the clay sealing material will not adversely affect the performance of a disposal vault

Innovative Seals for Solid Oxide Fuel Cells (SOFC)

Energy Technology Data Exchange (ETDEWEB)

Singh, Raj

2008-06-30

A functioning SOFC requires different type of seals such as metal-metal, metal-ceramic, and ceramic-ceramic. These seals must function at high temperatures between 600--900{sup o}C and in oxidizing and reducing environments of the fuels and air. Among the different type of seals, the metal-metal seals can be readily fabricated using metal joining, soldering, and brazing techniques. However, the metal-ceramic and ceramic-ceramic seals require significant research and development because the brittle nature of ceramics/glasses can lead to fracture and loss of seal integrity and functionality. Consequently, any seals involving ceramics/glasses require a significant attention and technology development for reliable SOFC operation. This final report is prepared to describe the progress made in the program on the needs, approaches, and performance of high temperature seals for SOFC. In particular, a new concept of self-healing glass seals is pursued for making seals between metal-ceramic material combinations, including some with a significant expansion mismatch.

21 CFR 864.9750 - Heat-sealing device.

Science.gov (United States)

2010-04-01

... and Blood Products § 864.9750 Heat-sealing device. (a) Identification. A heat-sealing device is a device intended for medical purposes that uses heat to seal plastic bags containing blood or blood... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Heat-sealing device. 864.9750 Section 864.9750...

Refurbishing the seals of the H2S compressors in the isotopic exchange installations at the Heavy Water Reprocessing Plant. Technical solutions for replacing liquid seals by dry seals

International Nuclear Information System (INIS)

Panait; Adrian; Serban, Viorel; Androne, Marian; Florea, Ioana; Ciocan, George; State, Elena

2004-01-01

An analysis of the present sealing system in the H 2 S compressors showed that the risk of accidental hydrogen sulfide escape into the atmosphere is high in case of a seal oil pressure loss. At the same time there exist drawbacks occurring even in normal regime of functioning among which one can mention: - relatively high losses of oil occur, part of the oil being carried away by the compressors and released into the isotopic exchange columns where the water counter current flow produces a foaming that reduces the column processing capacity; - part of the sealing oil leaks reaches the final product, the heavy water, where from it must be removed by chemical procedures; - the installations adjacent to the sealing system are relatively sophisticated and require relatively high expenses for exploitation and maintenance. The classical sealing systems using sealing rings, sleeves, labyrinths, etc, cannot be used since their safe working range is exceeded due to either driving shaft rotational speed, or to the increase of its diameter, or else to an increase of the speed of motion of moving parts relative to the fix parts. The sealing systems with magnetic liquids are rather sophisticated and expensive while in case of electric supply loss they are completely unsafe, because their sealing capacity vanishes. The materials used for sealing gaskets limit their application only to the cases when the relative motion of the moving pieces is low or vanishing what happens only at shut down or failure situations. To prevent these drawbacks of the present seal system in the H 2 S compressors of the isotopic exchange columns and having in view the limitations of the currently used sealing systems a new system of sealing was conceived and designed on the basis of the patent titled 'Sealing Installation and Procedure' recorded by OSIM under No. A/0315/10.04.2003. The new system can be built as a single or double stage each of them having in turn a dynamic and a static sub-stage. The

Face-Sealing Butterfly Valve

Science.gov (United States)

Tervo, John N.

1992-01-01

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

The Traumatic Tube: Bleeding Rectal Ulcer Caused by Flexi-Seal Device

Directory of Open Access Journals (Sweden)

Abhinav Tiwari

2017-01-01

Full Text Available Diarrhea and fecal incontinence are common in critically ill patients and present a challenging problem in patient management. The Flexi-Seal® Fecal Management System is a device to divert the stools away from the patient, thus improving the care to patients with fecal incontinence. There have been only few case reports describing the complications with the use of this device. Here, we present a case of a 77-year-old woman who was admitted due to massive hematochezia while on anticoagulation. She was found to have a large rectal ulcer caused by the Flexi-Seal device, used during the last hospital stay for fecal incontinence. Flexi-Seal device can be effective for the management of incontinence; however, caution should be exercised during handling and pressure from the retention balloon should be relieved periodically.

Spray sealing: A breakthrough in integral fuel tank sealing technology

Science.gov (United States)

Richardson, Martin D.; Zadarnowski, J. H.

1989-11-01

In a continuing effort to increase readiness, a new approach to sealing integral fuel tanks is being developed. The technique seals potential leak sources by spraying elastomeric materials inside the tank cavity. Laboratory evaluations project an increase in aircraft supportability and reliability, an improved maintainability, decreasing acquisition and life cycle costs. Increased usable fuel volume and lower weight than conventional bladders improve performance. Concept feasibility was demonstrated on sub-scale aircraft fuel tanks. Materials were selected by testing sprayable elastomers in a fuel tank environment. Chemical stability, mechanical properties, and dynamic durability of the elastomer are being evaluated at the laboratory level and in sub-scale and full scale aircraft component fatigue tests. The self sealing capability of sprayable materials is also under development. Ballistic tests show an improved aircraft survivability, due in part to the elastomer's mechanical properties and its ability to damp vibrations. New application equipment, system removal, and repair methods are being investigated.

Magnetically Actuated Seal, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — FTT proposes development of a magnetically actuated dynamic seal. Dynamic seals are used throughout the turbopump in high-performance, pump-fed, liquid rocket...

Magnetically Actuated Seal, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — FTT proposes development of a magnetically actuated dynamic seal. Dynamic seals are used throughout the turbopump in high-performance, pump-fed, liquid rocket...

Guide to optimized replacement of equipment seals

International Nuclear Information System (INIS)

Gleason, J.F.

1990-03-01

A reevaluation of current scheduled replacement intervals of polymeric seals in plant equipment can achieve significant benefits. Information is provided which has the potential for increasing replacement intervals based on better information on how seals have performed through unique nuclear industry tests to qualify equipment, improved elastomers and increased knowledge of the failure mechanisms and related performance. The research was performed by reviewing applications of elastomeric seals in nuclear plants and practice associated with defining seal replacement intervals in the nuclear power and other industries. Performance indicators and how they predict degradation of seals were evaluated. Guidelines and a flow chart for reevaluating seal replacement intervals are provided. 29 refs., 38 figs., 8 tabs

Analysis of end-face seals by FEM

Directory of Open Access Journals (Sweden)

Juraszek J.

2002-09-01

Full Text Available The end face-seals joint simultaneously the function of seal, bearing and heat exchanger. In order to improve the design of end-face seals the analysis of this type of joint by means of finite element method, was developed. The temperature distribution is indispensable to the analysis of displacement and stress in this type of face seal. In this work the values of temperature and stress in end-face seals were calculated. The numerical results were confirmed by measurements in the laboratory.

HMSRP Hawaiian Monk Seal Shark Predation Mitigation Shark Sightings and Incidents

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Data on direct sightings of large sharks around monk seal pupping sites and shark incidents on preweaned and newly weaned pups at French Frigate Shoals are entered...

Sealing device and method for sealing fractures or leaks in wall or formation surrounding tube-shaped channel

DEFF Research Database (Denmark)

2014-01-01

The sealing device (1) includes an elongated body (5) adapted to be introduced into a tube-shaped channel (2) and including a sealing fluid placement section (6) arranged between a first and a second annular flow barrier (7, 8). The elongated body further includes a sealing fluid activation secti...

Quick-sealing design for radiological containment

International Nuclear Information System (INIS)

Rampdla, D.S.; Speer, E.

1991-01-01

This patent describes a quick-sealing assembly and method for forming an adhesive seal on opposite sides of a mechanical seal for a flexible containment bag of the type used for working with radioactively contaminated objects. The assembly includes an elongated mechanical fastener having opposing engaging members affixed at a predetermined distance from each of the elongated edges, with an adhesive layer formed between the mechanical fastener and the elongated edge such that upon engagement of the mechanical fastener and adhesive layers to opposing containment fabric, a neat triple hermetic seal is formed

Quick-sealing design for radiological containment

International Nuclear Information System (INIS)

Rampolia, D.S.; Speer, E.

1990-01-01

This patent describes a quick-sealing assembly and method for forming an adhesive seal on opposite sides of a mechanical seal for a flexible containment bag of the type used for working with radioactively contaminated objects. The assembly includes an elongated mechanical fastener having opposing engaging members affixed at a predetermined distance from each of the elongated edges, with an adhesive layer formed between the mechanical fastener and the elongated edge such that upon engagement of the mechanical fastener and adhesive layers to opposing containment fabric, a neat triple hermetic seal is formed

Quick-sealing design for radiological containment

Science.gov (United States)

Rampolia, Donald S.; Speer, Elmer

1990-01-01

A quick-sealing assembly and method for forming an adhesive seal on opposite sides of a mechanical seal for a flexible containment bag of the type used for working with radioactively contaminated objects. The assembly includes an elongated mechanical fastener having opposing engaging members affixed at a predetermined distance from each of the elongated edges, with an adhesive layer formed between the mechanical fastener and the elongated edge such that upon engagement of the mechanical fastener and adhesive layers to opposing containment fabric, a neat triple hermetic seal is formed.

Auto-identification fiberoptical seal verifier

International Nuclear Information System (INIS)

Yamamoto, Yoichi; Mukaiyama, Takehiro

1998-08-01

An auto COBRA seal verifier was developed by Japan Atomic Energy Research Institute (JAERI) to provide more efficient and simpler inspection measures for IAEA safeguards. The verifier is designed to provide means of a simple, quantitative and objective judgment on in-situ verification for the COBRA seal. The equipment is a portable unit with hand-held weight and size. It can be operated by battery or AC power. The verifier reads a COBRA seal signature by using a built-in CCD camera and carries out the signature comparison procedure automatically on digital basis. The result of signature comparison is given as a YES/NO answer. The production model of the verifier was completed in July 1996. The development was carried out in collaboration with Mitsubishi Heavy Industries, Ltd. This report describes the design and functions of the COBRA seal verifier and the results of environmental and functional tests. The development of the COBRA seal verifier was carried out in the framework of Japan Support Programme for Agency Safeguards (JASPAS) as a project, JD-4 since 1981. (author)

The use of dual material seals for packaging

International Nuclear Information System (INIS)

Temus, C.J.; Nichols, J.C.

2004-01-01

The use of dual material seals, metal and elastomeric for a transportation package, provides a viable option for packages requiring high temperature seal capability. Allowing the seal area to go to higher temperatures then allowed for all elastomeric seal reduce the necessity of providing thermal protection during a postulated accident condition fire. It also increases the options for impact limiting features that do not also mitigate the affects of accident thermal events. Typically, high temperature seals require the use of metal O-rings. Only one seal (typically identified as the containment seal) needs to survive the hypothetical accident conditions, including the high temperatures that may occur during the prescribed hypothetical thermal event. However, to expedite the assembly leakage rate testing of radioactive material packages, a dual O-ring seal arrangement is often used to allow creation of a relatively small volume test cavity between the seals. For any package that is being used on a frequent basis, the total cost of seals can be significantly reduced by using an elastomeric seal as the secondary seal. The elastomeric seal is not the containment boundary seal and does not need to survive the high temperature condition. To get the dual material O-ring seals to seat properly, a different approach has to be taken than with closure of a radioactive material package that does not use metallic O-ring(s). A metal O-ring requires an application of a seating force while the elastomeric package requires a certain percentage of deformation. This is further complicated when the seating force is developed using a multi-bolt closure. Because of the nature of multi-bolt closures, elastic interaction prevents the equal application of force. This paper develops the methods involved in properly closing and establishing containment when using dual material seals with a multi-bolt closure. These methods were demonstrated in two production casks requiring testing leak

HFCVD Diamond-Coated Mechanical Seals

Directory of Open Access Journals (Sweden)

Raul Simões

2018-05-01

Full Text Available A mechanical seal promotes the connection between systems or mechanisms, preventing the escape of fluids to the exterior. Nonetheless, due to extreme working conditions, premature failure can occur. Diamond, due to its excellent properties, is heralded as an excellent choice to cover the surface of these devices and extend their lifetime. Therefore, the main objective of this work was to deposit diamond films over mechanical seals and test the coated seals on a water pump, under real working conditions. The coatings were created by hot filament chemical vapor deposition (HFCVD and two consecutive layers of micro- and nanocrystalline diamond were deposited. One of the main difficulties is the attainment of a good adhesion between the diamond films and the mechanical seal material (WC-Co. Nucleation, deposition conditions, and pre-treatments were studied to enhance the coating. Superficial wear or delamination of the film was investigated using SEM and Raman characterization techniques, in order to draw conclusions about the feasibility of these coatings in the WC-Co mechanical seals with the purpose of increasing their performance and life time. The results obtained gave a good indication about the feasibility of this process and the deposition conditions used, with the mechanical seals showing no wear and no film delamination after a real work environment test.

Laboratory studies of fluid flow through borehole seals

International Nuclear Information System (INIS)

South, D.L.

1983-01-01

Boreholes in the vicinity of a nuclear waste repository must be reliably sealed to prevent rapid migration of radionuclide contaminated water from the vicinity of the repository to the accessible environment. Few data currently exist regarding the effectiveness of borehole sealing. The objective of this research was to assess the performance of borehole seals under laboratory conditions, particularly with regard to varying stress fields. The approach used to evaluate borehole seals was to compare flow through a sealed borehole with flow through intact rock. Granite, basalt, and tuff were tested, using either cement or bentonite as the seal material. The main conclusions reached as a result of the experiments is that currently existing materials are capable of forming high quality seals when placed under laboratory conditions. Variation of triaxial stress state about a borehole does not significantly affect seal performance if the rock is stiffer than the seal material. Temperature/moisture variations (drying) degraded the quality of cement seals significantly. Performance partially recovered upon resaturation. Significant remaining questions include field emplacement techniques; field vertification of plug quality; plug performance over long time periods, particularly with respect to temperature/moisture variations and chemical stability; and radionuclide sorption capabilities. Scale effects are also important, as shafts and drifts must be sealed as well as larger diameter boreholes

Miniature magnetic fluid seal working in liquid environments

Science.gov (United States)

Mitamura, Yoshinori; Durst, Christopher A.

2017-06-01

This study was carried out to develop a miniature magnetic fluid (MF) seal working in a liquid environment. The miniature MF seal is intended for use in a catheter blood pump. The requirements for the MF seal included a size of less than Ø4×4.5 mm, shaft diameter of 1 mm, sealing pressure of 200 mmHg, shaft speed of up to 40000 rpm, and life of one month. The miniature MF seal was composed of an NdFeB magnet (Ø4×Ø2×1) sandwiched between two pole pieces (Ø4×Ø1.1×0.5). A shield (Ø4×Ø1.2×1.5) was placed on the pole piece facing the liquid to minimize the influence of pump flow on the MF. The seal was installed on a Ø1 shaft. A seal was formed by injecting MF (Ms: 47.8 kA/m and η: 0.5 Pa·sec) into the gap between the pole pieces and the shaft. Total volume of the MF seal was 44 μL. A sealing pressure of 370 mmHg was obtained at motor speeds of 0-40,000 rpm. The seal remained perfect for 10 days in saline under the condition of a pump flow of 1.5 L/min (The test was terminated in accordance with plans). The seal remained intact after ethylene oxide sterilization during which the seal was exposed to high pressures. In conclusion, the newly developed MF seal will be useful for a catheter pump.

Application of EIS to In Situ Characterization of Hydrothermal Sealing of Anodized Aluminum Alloys: Comparison between Hexavalent Chromium-Based Sealing, Hot Water Sealing and Cerium-Based Sealing

OpenAIRE

Carangelo, Anna; Curioni, Michele; Acquesta, Annalisa; Monetta, Tullio; Bellucci, Francesco

2016-01-01

Chromic acid anodizing has been used for almost a century to enhance corrosion protection of aerospace alloys. For some applications,hydrothermal sealing in hexavalent chromium-containing solution is required to enhance further the corrosion resistance but, due toenvironmental concerns, the use of hexavalent chromium must be discontinued. Good progress has been made to replace chromatesduring anodizing but comparatively less effort has focused on the sealing process. In this work, for the fir...

Numerical Investigation on Windback Seals Used in Aero Engines

Directory of Open Access Journals (Sweden)

Michael Flouros

2018-01-01

Full Text Available Seals are considered one of the most important flow elements in turbomachinery applications. The most traditional and widely known seal is the labyrinth seal but in recent years other types like the brush or carbon seals were introduced since they considerably reduce the sealing air consumption. When seals are used for sealing of aero engine bearing chambers they are subjected to high “bombardment” through oil particles which are present in the bearing chamber. These particles mainly result from the bearings as a consequence of the high rotational speeds. Particularly when carbon or brush seals are used, problems with carbon formation (coking may arise when oil gets trapped in the very tight gap of these seals. In order to prevent oil migration into the turbomachinery, particularly when the pressure difference over a seal is small or even negligible, significant improvement can be achieved through the introduction of so called windback seals. This seal has a row of static helical teeth (thread and below this thread a scalloped or smooth shaft section is rotating. Depending on the application, a windback seal can be used alone or as a combination with another seal (carbon, brush or labyrinth seal. A CFD analysis carried out with ANSYS CFX version 11 is presented in this paper with the aim to investigate this seal type. The simulations were performed by assuming a two-phase flow of air and oil in the bearing compartment. Design parameters like seal clearance, thread size, scallop width, were investigated at different operating conditions.

Sealing Occlusal Dentin Caries in Permanent Molars

DEFF Research Database (Denmark)

Qvist, Vibeke; Borum, Mette Kit; Møller, Kirsten Dynes

2017-01-01

The purpose of this study was to investigate the possibility of postponing restorative intervention of manifest occlusal caries in young, permanent dentition by non-invasive sealing. This RCT-designed study included 521 occlusal lesions in 521 patients aged 6 to 17 y. Based on clinical and radiog......The purpose of this study was to investigate the possibility of postponing restorative intervention of manifest occlusal caries in young, permanent dentition by non-invasive sealing. This RCT-designed study included 521 occlusal lesions in 521 patients aged 6 to 17 y. Based on clinical...... longevity of sealings and restorations until retreatments, and 3) compare effectiveness of sealings and restorations to halt caries progression in sealed lesions and beneath restorations. Furthermore, we aimed to identify factors influencing longevity and the effectiveness of sealings and restorations.......001). The median survival time for sealings not replaced by restorations was 7.3 y (CI, 6.4 y to NA). Survival of sealings was increased in patients with low caries risk and/or excellent oral hygiene, second molars compared with first molars, and lesions not extending the middle one-third of the dentin. Survival...

Design and construction of a large-scale sand-bentonite seal for controlled gas release from a L/ILW repository - The GAST project at GTS

International Nuclear Information System (INIS)

Rueedi, J.; Marschall, P.; Vaissiere, R. de la; Jung, H.; Reinhold, M.; Steiner, P.; Garcia-Sineriz, J.L.

2012-01-01

experiments on the real scale are needed for benchmarking the performance of the two-phase flow models. The Gas-Permeable Seal Test (GAST) was initiated in 2010 as a GTS partner project with Andra and KRMC as project partners. The experiment was emplaced at Grimsel Test Site (GTS) in 2011/2012. The S/B seal with a length of 8 m and a diameter of 3m was emplaced to demonstrate the effective functioning of gas permeable seals at realistic scales and under realistic hydraulic boundary conditions ('proof of concept'). The latter condition required the experiment to be emplaced in an existing TBM (tunnel boring machine) drilled tunnel at GTS where the surrounding granite has shown to provide a negligible excavation damaged zone (EDZ) and the stiff rock enables water injection at pressures similar to those expected for a L/ILW repository seal, i.e. 3-5 MPa corresponding to the hydrostatic pressure at 300-500 m depth. The S/B body was compacted manually in horizontal sheets of about 10 cm thickness with a target dry density of 1.7 g/cm 3 . The remaining head space as well as all S/B interfaces (i.e. towards granite and concrete plug) were sealed with granular bentonite and/or with bentonite blocks. The experiment is planned to be saturated until 2014 followed by gas injection from the far end of the tunnel in 2015. The experiment aims at validating and, if necessary, improving current conceptual models for the re-saturation and gas invasion processes into S/B seals and the determination of up-scaled gas / water permeabilities of S/B seals (i.e. two-phase flow parameters for large-scale models). For this reason material saturation, water pressures and earth pressures are monitored continuously by more than 150 sensors distributed among 15 instrumentation cross sections, comprising of piezometers for pore pressure, relative humidity sensors, psychrometers and TDRs for water saturation, total pressure cells for stress state and piezo-crystals for seismic tomography. All instruments and

Floating seal system for rotary devices

Science.gov (United States)

Banasiuk, H.A.

1983-08-23

This invention relates to a floating seal system for rotary devices to reduce gas leakage around the rotary device in a duct and across the face of the rotary device to an adjacent duct. The peripheral seal bodies are made of resilient material having a generally U-shaped cross section wherein one of the legs is secured to a support member and the other of the legs forms a contacting seal against the rotary device. The legs of the peripheral seal form an extended angle of intersection of about 10[degree] to about 30[degree] in the unloaded condition to provide even sealing forces around the periphery of the rotary device. The peripheral seal extends around the periphery of the support member except where intersected by radial seals which reduce gas leakage across the face of the rotary device and between adjacent duct portions. The radial seal assembly is fabricated from channel bars, the smaller channel bar being secured to the divider of the support member and a larger inverted rigid floating channel bar having its legs freely movable over the legs of the smaller channel bar forming therewith a tubular channel. A resilient flexible tube is positioned within the tubular channel for substantially its full length to reduce gas leakage across the tubular channel. A spacer extends beyond the face of the floating channel near each end of the floating channel a distance to provide desired clearance between the floating channel and the face of the rotary device. 5 figs.

Apparatus and method for inspecting a sealed container

Science.gov (United States)

Harmon, J Frank [Pocatello, ID; Jones, James L [Idaho Falls, ID; Hunt, Alan W [Pocatello, ID; Spaulding, Randy J [Pocatello, ID; Smith, Michael [Phoenix, AZ

2009-03-24

An apparatus for inspecting a sealed container is disclosed and which includes a pulsed electron accelerator which is positioned in spaced relation relative to a first side of the sealed container, and which produces a pulsed beam of photons which passes through the sealed container and any contents enclosed within the sealed container; a detector positioned in spaced relation relative to a second, opposite side of the sealed container, and which receives the pulsed beam of photons which passes through the contents of the sealed container, and which produces an output signal; and a computer for developing a visible image from the output signal of the detector which depicts the contents of the sealed container.

Selection of vacuum seals for EBT-P

International Nuclear Information System (INIS)

Dillow, C.F.; Adlon, G.L.; Stubblefield, V.E.

1981-01-01

Elmo Bumpy Torus Proof of Principle (EBT-P) is a magnetic fusion RandD facility being constructed by McDonnell Douglas Astronautics Company - St. Louis Division of Oak Ridge National Laboratory (ORNL). EBT-P is a truly unique fusion device requiring careful consideration in selecting both the primary vacuum seals on the toroidal vessel and the secondary vacuum seals in components such as vacuum pumps and and valves. The vacuum seal environment is described and the considerations in vacuum seal selection fully discussed. Methods for protecting vacuum seals in pumps and valves from the microwave environments are also presented

Robert Aymar seals the last interconnect in the LHC

CERN Multimedia

Maximilien Brice

2007-01-01

The LHC completes the circle. On 7 November, in a brief ceremony in the LHC tunnel, CERN Director General Robert Aymar (Photo 1) sealed the last interconnect between the main magnets of the Large Hadron Collider (LHC). Jean-Philippe Tock, leader of the Interconnections team, tightens the last bolt (Photos 4-8).

Seal analysis technology for reactor pressure vessel

International Nuclear Information System (INIS)

Zheng Liangang; Zhang Liping; Yang Yu; Zang Fenggang

2009-01-01

There is the coolant with radiation, high temperature and high pressure in the reactor pressure vessel (RPV). It is closely correlated to RPV sealing capability whether the whole nuclear system work well or not. The aim of this paper is to study the seal analysis method and technology, such as the pre-tensioning of the bolt, elastoplastic contact and coupled technology of thermal and structure. The 3 D elastoplastic seal analysis method really and generally consider the loads and model the contact problem with friction between the contact plates. This method is easier than the specialized seal program and used widely. And it is more really than the 2 D seal analysis method. This 3 D elastoplastic seal analysis method has been successfully used in the design and analysis of RPV. (authors)

Sealed radioactive sources toolkit

International Nuclear Information System (INIS)

Mac Kenzie, C.

2005-09-01

The IAEA has developed a Sealed Radioactive Sources Toolkit to provide information to key groups about the safety and security of sealed radioactive sources. The key groups addressed are officials in government agencies, medical users, industrial users and the scrap metal industry. The general public may also benefit from an understanding of the fundamentals of radiation safety

Method and system to facilitate sealing in gas turbines

Science.gov (United States)

Morgan, Victor John; Foster, Gregory Thomas; Sarawate, Neelesh Nandkumar

2017-09-12

A method and system for sealing between components within a gas turbine is provided. A first recess defined in a first component receives a seal member. A second recess defined in a second component adjacent the first component also receives the seal member. The first and second recesses are located proximate a hot gas path defined through the gas turbine, and define circumferential paths about the turbine axis. The seal member includes a sealing face that extends in a direction substantially parallel to the turbine axis. The seal member also includes a plurality of seal layers, wherein at least one of the seal layers includes at least one stress relief region for facilitating flexing of the first seal member.

Silicone foam for penetration seal

International Nuclear Information System (INIS)

Hoshino, Yoshikazu

1986-01-01

In nuclear power plants or general buildings, it is very important to form a fire-resistant seal around cables, cable trays and conduits passing through a wall or a floor. Rockwool, asbestos, glasswool and flame-retarded urethane foam have so far been used for these purposes. However, they were not satisfactory in sealing property, workability and safety. The silicone foam newly developed, ''TOSSEAL'' 300, has cleared these defects. It has now come to be used for fire resistant seal in nuclear power plants. (author)

Infiltrating/sealing proximal caries lesions

DEFF Research Database (Denmark)

Martignon, S; Ekstrand, K R; Gomez, J

2012-01-01

This randomized split-mouth controlled clinical trial aimed at assessing the therapeutic effects of infiltration vs. sealing for controlling caries progression on proximal surfaces. Out of 90 adult students/patients assessed at university clinics and agreeing to participate, 39, each with 3...... differences in lesion progression between infiltration and placebo (P = 0.0012) and between sealing and placebo (P = 0.0269). The study showed that infiltration and sealing are significantly better than placebo treatment for controlling caries progression on proximal lesions. No significant difference...

Endovascular Aneurysm Repair and Sealing (EVARS): A Useful Adjunct in Treating Challenging Morphology

Energy Technology Data Exchange (ETDEWEB)

Harrison, Gareth J., E-mail: garethjamesharrison@yahoo.co.uk; Antoniou, George A., E-mail: antoniou.ga@hotmail.com; Torella, Francesco, E-mail: francesco.torella@rlbuht.nhs.uk; McWilliams, Richard G., E-mail: richard.mcwilliams@rlbuht.nhs.uk; Fisher, Robert K., E-mail: robert.fisher@rlbuht.nhs.uk [Royal Liverpool University Hospital, Liverpool Vascular and Endovascular Service (United Kingdom)

2016-04-15

An 81-year-old male with previous open abdominal aortic aneurysm repair presented with asymptomatic large pseudoaneurysms at both ends of an open surgical tube graft. Endovascular aneurysm sealing (EVAS) in combination with the iliac limbs of a standard endovascular aneurysm repair (EVAR) successfully excluded both pseudoaneurysms from circulation. We describe the combination of elements of EVAS and EVAR and have termed this endovascular aneurysm repair and sealing (EVARS). EVARS has the advantage of harnessing the benefits of endobag sealing in aortic necks unsuitable for standard EVAR whilst providing the security of accurate stent placement within short common iliac arteries. In conclusion, EVAS may be combined with standard endovascular iliac limbs and is a possible treatment option for pseudoaneurysm following open aneurysm repair.

Cost saving synergistic shaft seal

Science.gov (United States)

Ludwig, L. P.; Strom, T. N.

1976-01-01

Segmented carbon rings, used to replace elastomeric seal lip, provide resistance to high temperatures generated in lubricating film. Machining and close manufacturing tolerances of conventional segmented seal are avoided by mounting segmented rings in elastomeric flex section.

Development of a ceramic tamper indicating seal: SRNL contributions

International Nuclear Information System (INIS)

Krementz, Dan; Brinkman, Kyle S.; Martinez-Rodriguez, Michael J.; Mendez-Torres, Adrian E.; Weeks, George E.

2013-01-01

Savannah River National Laboratory (SRNL) and Sandia National Laboratories (SNL) are collaborating on development of a Ceramic Seal, also sometimes designated the Intrinsically Tamper Indicating Ceramic Seal (ITICS), which is a tamper indicating seal for international safeguards applications. The Ceramic Seal is designed to be a replacement for metal loop seals that are currently used by the IAEA and other safeguards organizations. The Ceramic Seal has numerous features that enhance the security of the seal, including a frangible ceramic body, protective and tamper indicating coatings, an intrinsic unique identifier using Laser Surface Authentication, electronics incorporated into the seal that provide cryptographic seal authentication, and user-friendly seal wire capture. A second generation prototype of the seal is currently under development whose seal body is of Low Temperature Co-fired Ceramic (LTCC) construction. SRNL has developed the mechanical design of the seal in an iterative process incorporating comments from the SNL vulnerability review team. SRNL is developing fluorescent tamper indicating coatings, with recent development focusing on optimizing the durability of the coatings and working with a vendor to develop a method to apply coatings on a 3-D surface. SRNL performed a study on the effects of radiation on the electronics of the seal and possible radiation shielding techniques to minimize the effects. SRNL is also investigating implementation of Laser Surface Authentication (LSA) as a means of unique identification of each seal and the effects of the surface coatings on the LSA signature.

DEVELOPMENT OF A CERAMIC TAMPER INDICATING SEAL: SRNL CONTRIBUTIONS

Energy Technology Data Exchange (ETDEWEB)

Krementz, D.; Brinkman, K.; Martinez-Rodriguez, M.; Mendez-Torres, A.; Weeks, G.

2013-06-03

Savannah River National Laboratory (SRNL) and Sandia National Laboratories (SNL) are collaborating on development of a Ceramic Seal, also sometimes designated the Intrinsically Tamper Indicating Ceramic Seal (ITICS), which is a tamper indicating seal for international safeguards applications. The Ceramic Seal is designed to be a replacement for metal loop seals that are currently used by the IAEA and other safeguards organizations. The Ceramic Seal has numerous features that enhance the security of the seal, including a frangible ceramic body, protective and tamper indicating coatings, an intrinsic unique identifier using Laser Surface Authentication, electronics incorporated into the seal that provide cryptographic seal authentication, and user-friendly seal wire capture. A second generation prototype of the seal is currently under development whose seal body is of Low Temperature Co-fired Ceramic (LTCC) construction. SRNL has developed the mechanical design of the seal in an iterative process incorporating comments from the SNL vulnerability review team. SRNL is developing fluorescent tamper indicating coatings, with recent development focusing on optimizing the durability of the coatings and working with a vendor to develop a method to apply coatings on a 3-D surface. SRNL performed a study on the effects of radiation on the electronics of the seal and possible radiation shielding techniques to minimize the effects. SRNL is also investigating implementation of Laser Surface Authentication (LSA) as a means of unique identification of each seal and the effects of the surface coatings on the LSA signature.

Radiocaesium and polonium in seals from Swedish coastal waters

International Nuclear Information System (INIS)

Holm, E.A.B.; Leisvik, M.A.; Holm, E.A.B

2004-01-01

Radiocaesium, 137 Cs (T 1/2 = 30 a) and 210 Po (T 1/2 = 138 d) have been studied in tissues (muscle, liver, kidney and gonads/ovaries) from a large number of seals from the Baltic Sea and the Swedish west coast during 1995-2002. The Baltic Sea is a marginal sea with long residence time for dissolved compounds. Concentrations of radiocaesium increased 10 fold in the Baltic Sea following the Chernobyl accident, while concentrations of polonium can be supposed to be in equilibrium except for seasonal variations. The major food for seals in the Baltic proper is fish, while at the west coast other food stuff such as crustaceans play an important role. By supposing that the seals consume 5% of their body-weight per day and by using known data for caesium and polonium in fish the biological half-life in seals is estimated to 20 days for Caesium and 35 days for Polonium. Radiocaesium is evenly distributed in the organs of the seals and was about 100 Bq kg -1 in the Baltic Sea while at the west coast the concentrations were significantly lower, about 5-30 Bq kg -1 . Polonium shows the highest concentrations in kidney, about 100-200 Bq kg -1 d.w. in the Baltic sea and higher concentrations 100-1000 Bq kg -1 at the west coast. This reflects clearly the differences in food choice/availability in the different areas. The estimated maximal doses were 76 μSv per year to muscle from 137 Cs and 6.8 mSv from 210 Po to kidney. Seals constitute a good bio-marker for radioactivity in Swedish coastal waters. Concentration factors are higher for radiocaesium in the Baltic Sea due to lower salinity and consequently higher concentrations in fish compared to other areas, but lower for polonium than in areas where crustaceans also constitute an important foodstuff. (author)

Improved sealing for in-core systems

International Nuclear Information System (INIS)

Dunford, S.

1989-01-01

The in-core instrumentation sealing nozzles designed by Framatome have three mechanical seals in series instead of the one traditional seal, and are pressurized by simply tightening up the nozzle covers. They have been installed from the start on all Framatome PWRs, as well as having been backfitted on Belgium and Yugoslavian units and chosen for the Chinese Qinshan plant. (author)

Multi-Canister overpack sealing configuration

International Nuclear Information System (INIS)

SMITH, K.E.

1998-01-01

The Spent Nuclear Fuel (SNF) position regarding the Multi-Canister Overpack (MCO) sealing configuration is to initially rely on an American Society of Mechanical Engineers (ASME) Section III Subsection NB code compliant mechanical closure/sealing system to quickly and safely establish and maintain full confinement of radioactive materials prior to and during MCO fuel drying activities. Previous studies have shown the mechanical seal to be the preferred closure method, based on dose, cost, and schedule considerations. The cost and schedule impacts of redesigning the mechanical closure to a welded shield plug do not support changing the closure system. The SNF Project has determined that the combined mechanical/welded closure system meets or exceeds the regulatory requirements to provide redundant seals while accommodating key safety and schedule limitations that are unique to K Basins fuel removal effort

Coupled processes in repository sealing

International Nuclear Information System (INIS)

Case, J.B.; Kelsall, P.C.

1985-01-01

The significance of coupled processes in repository sealing is evaluated. In most repository designs, shaft seals will be located in areas of relatively low temperature perturbation, in which case the coupling of temperature with stress and permeability may be less significant than the coupling between stress and permeability that occurs during excavation. Constitutive relationships between stress and permeability are reviewed for crystalline rock and rocksalt. These provide a basis for predicting the development of disturbed zones near excavations. Field case histories of the degree of disturbance are presented for two contrasting rock types - Stripa granite and Southeastern New Mexico rocksalt. The results of field investigations in both rock types confirm that hydraulic conductivity or permeability is stress dependent, and that shaft seal performance may be related to the degree that stresses are perturbed and restored near the seal

Sealing glasses for titanium and titanium alloys

Science.gov (United States)

Brow, Richard K.; McCollister, Howard L.; Phifer, Carol C.; Day, Delbert E.

1997-01-01

Barium lanthanoborate sealing-glass compositions are provided comprising various combinations (in terms of mole-%) of boron oxide (B.sub.2 O.sub.3), barium oxide (BaO), lanthanum oxide (La.sub.2 O.sub.3), and at least one other oxide selected from the group consisting of aluminum oxide (Al.sub.2 O.sub.3), calcium oxide (CaO), lithium oxide (Li.sub.2 O), sodium oxide (Na.sub.2 O), silicon dioxide (SiO.sub.2), or titanium dioxide (TiO.sub.2). These sealing-glass compositions are useful for forming hermetic glass-to-metal seals with titanium and titanium alloys having an improved aqueous durability and favorable sealing characteristics. Examples of the sealing-glass compositions are provided having coefficients of thermal expansion about that of titanium or titanium alloys, and with sealing temperatures less than about 900.degree. C., and generally about 700.degree.-800.degree. C. The barium lanthanoborate sealing-glass compositions are useful for components and devices requiring prolonged exposure to moisture or water, and for implanted biomedical devices (e.g. batteries, pacemakers, defibrillators, pumps).

Sealing of polymer micro-structures by over-moulding

DEFF Research Database (Denmark)

Vingaard, Mathias; Christiansen, Jesper de Claville

2012-01-01

A concept for sealing of polymer micro-structures by over-moulding with polystyrene was devised and investigated by both experiments and simulations. The depth to which the melt filled the structure, i.e. a groove in the surface of the insert, before solidification was compared with results from...... simulations by computational fluid dynamics software. In both experiments and simulations, there was clearly an increase of filling depth with groove width and, especially for wide grooves, with injection temperature. In the simulations, changes in prescribed heat transfer coefficient had the largest effect...... on filling depth in the narrowest grooves. Around the experimental groove widths, there was good agreement between experiments and simulations. It was concluded that sealing by over-moulding is feasible if the depth/width ratio of the structure is large enough which in this paper is larger than six, i.e. up...

Exposing the grey seal as a major predator of harbour porpoises

NARCIS (Netherlands)

Leopold, M.F.; Begeman, L.; van Bleijswijk, J.D.L.; IJsseldijk, L.L.; Witte, H.; Gröne, A.

2015-01-01

Harbour porpoises (Phocoena phocoena) stranding in large numbers around the southern North Sea with fatal, sharp-edged mutilations have spurred controversy among scientists, the fishing industry and conservationists, whose views about the likely cause differ. The recent detection of grey seal

Development of Advanced Carbon Face Seals for Aircraft Engines

Science.gov (United States)

Falaleev, S. V.; Bondarchuk, P. V.; Tisarev, A. Yu

2018-01-01

Modern aircraft gas turbine engines require the development of seals which can operate for a long time with low leakages. The basic type of seals applied for gas turbine engine rotor supports is face seal. To meet the modern requirements of reliability, leak-tightness and weight, low-leakage gas-static and hydrodynamic seals have to be developed. Dry gas seals use both gas-static and hydrodynamic principles. In dry gas seals microgrooves are often used, which ensure the reverse injection of leakages in the sealed cavity. Authors have developed a calculation technique including the concept of coupled hydrodynamic, thermal and structural calculations. This technique allows to calculate the seal performance taking into account the forces of inertia, rupture of the lubricant layer and the real form of the gap. Authors have compared the efficiency of seals with different forms of microgrooves. Results of calculations show that seal with rectangular form of microgrooves has a little gap leading to both the contact of seal surfaces and the wear. Reversible microgrooves have a higher oil mass flow rate, whereas HST micro-grooves have good performance, but they are difficult to produce. Spiral microgrooves have both an acceptable leakages and a high stiffness of liquid layer that is important in terms of ensuring of sealing performance at vibration conditions. Therefore, the spiral grooves were chosen for the developed seal. Based on calculation results, geometric dimensions were chosen to ensure the reliability of the seal operation by creating a guaranteed liquid film, which eliminates the wear of the sealing surfaces. Seals designed were tested both at the test rig and in the engine.

Development of simplified rotating plug seal structure

International Nuclear Information System (INIS)

Ueta, M.; Ichimiya, M.; Kanaoka, T.; Sekiya, H.; Ueda, S.; Ishibashi, S.

1991-01-01

We studied a compact and simplified rotating plug seal structure and conducted experiments for key elements of the concept such us the mechanical seal structure and sodium deposit prevention system. Good characteristics were confirmed for the mechanical seal structure, which utilizes an elastomer seal and thin lathe bearing. Applicability of the density barrier concept was also confirmed as the sodium deposit prevention system. This concept can be applied to actual plants. (author)

Global climate change: Mitigation opportunities high efficiency large chiller technology

Energy Technology Data Exchange (ETDEWEB)

Stanga, M.V.

1997-12-31

This paper, comprised of presentation viewgraphs, examines the impact of high efficiency large chiller technology on world electricity consumption and carbon dioxide emissions. Background data are summarized, and sample calculations are presented. Calculations show that presently available high energy efficiency chiller technology has the ability to substantially reduce energy consumption from large chillers. If this technology is widely implemented on a global basis, it could reduce carbon dioxide emissions by 65 million tons by 2010.

Sealing apparatus for airfoils of gas turbine engines

Science.gov (United States)

Jones, R.B.

1998-05-19

An improved airfoil tip sealing apparatus is disclosed wherein brush seals are attached to airfoil tips with the distal ends of the brush seal fibers sealingly contacting opposing wall surfaces. Embodiments for variable vanes, stators and both cooled and uncooled turbine blade applications are disclosed. 17 figs.

Reactor coolant pump shaft seal stability during station blackout

International Nuclear Information System (INIS)

Rhodes, D.B.; Hill, R.C.; Wensel, R.G.

1987-05-01

Results are presented from an investigation into the behavior of Reactor Coolant Pump shaft seals during a potential station blackout (loss of all ac power) at a nuclear power plant. The investigation assumes loss of cooling to the seals and focuses on the effect of high temperature on polymer seals located in the shaft seal assemblies, and the identification of parameters having the most influence on overall hydraulic seal performance. Predicted seal failure thresholds are presented for a range of station blackout conditions and shaft seal geometries

Reactor coolant pump shaft seal stability during station blackout

Energy Technology Data Exchange (ETDEWEB)

Rhodes, D B; Hill, R C; Wensel, R G

1987-05-01

Results are presented from an investigation into the behavior of Reactor Coolant Pump shaft seals during a potential station blackout (loss of all ac power) at a nuclear power plant. The investigation assumes loss of cooling to the seals and focuses on the effect of high temperature on polymer seals located in the shaft seal assemblies, and the identification of parameters having the most influence on overall hydraulic seal performance. Predicted seal failure thresholds are presented for a range of station blackout conditions and shaft seal geometries.

Trace element analysis in the serum and hair of Antarctic leopard seal, Hydrurga leptonyx, and Weddell seal, Leptonychotes weddellii

Energy Technology Data Exchange (ETDEWEB)

Gray, Rachael [Faculty of Veterinary Science, University of Sydney, NSW 2006 Australia (Australia); Australian Marine Mammal Research Centre PO Box 20 Mosman, NSW 2088 (Australia)], E-mail: rgray@vetsci.usyd.edu.au; Canfield, Paul [Faculty of Veterinary Science, University of Sydney, NSW 2006 (Australia); Rogers, Tracey [Australian Marine Mammal Research Centre PO Box 20 Mosman, NSW 2088 (Australia); Evolution and Ecology Research Centre and School of Biological Earth and Environmental Sciences, University of New South Wales, NSW 2052 (Australia)

2008-07-25

Leopard seal, Hydrurga leptonyx, and Weddell seal, Leptonychotes weddellii, occupy an upper trophic level within the Antarctic ecosystem and are useful indicator species in the Southern Ocean of trace element concentrations. Reference values for the concentration of 19 trace elements were determined in the serum and hair of leopard and Weddell seals sampled in Eastern Antarctica. These reference values can be used as 'baseline' levels for monitoring trace element concentrations in these species. Greater trace element concentrations were determined in hair compared to serum, indicating different time scales of trace element accumulation in these samples. For the majority of trace elements, except for Se in the leopard seal samples and Cr in the Weddell seal samples, significant regression relationships for trace element concentrations in hair and serum were not elucidated. Significant differences were determined in the concentrations of seven out of 15 elements with hair type, moult and new, in the leopard seal; concentrations in moult hair were determined to be greater than in new hair for all elements except Zn. Hair analysis was determined to be useful for monitoring exposure to trace elements and when collected off the ice from moulting seals, hair can be employed as a non-invasive sample for trace element analysis in leopard and Weddell seals.

Solid oxide fuel cell having a glass composite seal

Science.gov (United States)

De Rose, Anthony J.; Mukerjee, Subhasish; Haltiner, Jr., Karl Jacob

2013-04-16

A solid oxide fuel cell stack having a plurality of cassettes and a glass composite seal disposed between the sealing surfaces of adjacent cassettes, thereby joining the cassettes and providing a hermetic seal therebetween. The glass composite seal includes an alkaline earth aluminosilicate (AEAS) glass disposed about a viscous glass such that the AEAS glass retains the viscous glass in a predetermined position between the first and second sealing surfaces. The AEAS glass provides geometric stability to the glass composite seal to maintain the proper distance between the adjacent cassettes while the viscous glass provides for a compliant and self-healing seal. The glass composite seal may include fibers, powders, and/or beads of zirconium oxide, aluminum oxide, yttria-stabilized zirconia (YSZ), or mixtures thereof, to enhance the desirable properties of the glass composite seal.

Piston rod seal for a Stirling engine

Science.gov (United States)

Shapiro, Wilbur

1984-01-01

In a piston rod seal for a Stirling engine, a hydrostatic bearing and differential pressure regulating valve are utilized to provide for a low pressure differential across a rubbing seal between the hydrogen and oil so as to reduce wear on the seal.

Folded membrane dialyzer with mechanically sealed edges

Energy Technology Data Exchange (ETDEWEB)

Markley, F.W.

A semipermeable membrane is folded in accordion fashion to form a stack of pleats and the edges are sealed so as to isolate the opposite surfaces of the membrane. The stack is contained within a case that provides ports for flow of blood in contact with one surface of the membrane through channels formed by the pleats and also provides ports for flow of a dialysate through channels formed by the pleats in contact with the other surface of the membrane. The serpentine side edges of the membrane are sealed by a solidified plastic material, whereas effective mechanical means are provided to seal the end edges of the folded membrane. The mechanical means include a clamping strip which biases case sealing flanges into a sealed relationship with end portions of the membrane near the end edges, which portions extend from the stack and between the sealing flanges.

30 CFR 75.337 - Construction and repair of seals.

Science.gov (United States)

2010-07-01

... sealed areas. (b) Prior to sealing, the mine operator shall— (1) Remove insulated cables, batteries, and other potential electric ignition sources from the area to be sealed when constructing seals, unless it... after April 18, 2008, the seal at the lowest elevation shall have a corrosion-resistant, non-metallic...

Liquid-metal dip seal with pneumatic spring

International Nuclear Information System (INIS)

Poindexter, A.M.

1977-01-01

An improved liquid-metal dip seal for sealing the annulus between rotating plugs in the reactor vessel head of a liquid-metal fast-breeder nuclear reactor has two legs of differing widths communicating under a seal blade; the wide leg is also in communication with cover gas of the reactor and the narrow leg is also in communication with an isolated plug annulus above the seal. The annulus contains inert gas which acts as a pneumatic spring. Upon increasing cover gas pressure which depresses the level in the wide leg and greatly increases the level in the narrow leg, the pneumatic spring is compressed, and resists further level changes, thus preventing radioactive cover gas from bubbling through the seal

Experimental toxoplasma gondii infection in grey seals (Halichoerus grypus)

DEFF Research Database (Denmark)

Gajadhar, A. A.; Measures, L.; Forbes, L. B.

2004-01-01

Laboratory-reared animals were used to assess the susceptibility of seals (Halichoerus grypus) to Toxoplasma gondii infection. Four seals were each orally inoculated with 100 or 10,000 oocysts of T. gondii (VEG strain), and another 4 seals served as negative controls. Occasionally, mild behavioral...... changes were observed in all inoculated seals but not in control animals. A modified agglutination test revealed the presence of antibodies to T. gondii in sera collected from inoculated seals and mice inoculated as controls. No evidence of the parasite was found on an extensive histological examination...... of seal tissues, and immunohistochemical staining of tissue sections from inoculated seals revealed a single tissue cyst in only 1 seal. Control mice inoculated with 10 oocysts from the same inoculum given to seals became serologically and histologically positive for T. gondii. Cats that were fed brain...

Low torque hydrodynamic lip geometry for rotary seals

Science.gov (United States)

Dietle, Lannie L.; Schroeder, John E.

2015-07-21

A hydrodynamically lubricating geometry for the generally circular dynamic sealing lip of rotary seals that are employed to partition a lubricant from an environment. The dynamic sealing lip is provided for establishing compressed sealing engagement with a relatively rotatable surface, and for wedging a film of lubricating fluid into the interface between the dynamic sealing lip and the relatively rotatable surface in response to relative rotation that may occur in the clockwise or the counter-clockwise direction. A wave form incorporating an elongated dimple provides the gradual convergence, efficient impingement angle, and gradual interfacial contact pressure rise that are conducive to efficient hydrodynamic wedging. Skewed elevated contact pressure zones produced by compression edge effects provide for controlled lubricant movement within the dynamic sealing interface between the seal and the relatively rotatable surface, producing enhanced lubrication and low running torque.

Turbine and Structural Seals Team Facilities

Data.gov (United States)

Federal Laboratory Consortium — Seals Team Facilities conceive, develop, and test advanced turbine seal concepts to increase efficiency and durability of turbine engines. Current projects include...

Tamper-indicating devices and safeguards seals evaluation test report

International Nuclear Information System (INIS)

Horton, P.R.V.; Waddoups, I.G.

1993-12-01

Sandia National Laboratories was asked to evaluate the seals used as tamper-indicating devices (TIDs) at DOE facilities. Initially, a survey determined what seal manufacturers were being used and what similar seal types were available. Once the required specifications for TIDs were defined, a test plan measured the currently available seals against the requirements. Environmental and physical type tests stressed the seals under two broad categories: (1) handling durability and (2) tamper resistance. Results of the testing provide comparative ratings for the various seals, recommendations for using currently available seals, and a new tamper-indicating technology

Design and research of seal structure for thermocouple column assembly

International Nuclear Information System (INIS)

Rao Qiqi; Li Na; Zhao Wei; Ma Zhigang

2015-01-01

The new seal structure was designed to satisfy the function of thermocouple column assembly and the reactor structure. This seal structure uses the packing graphite ring and adopts the self-sealing principle. Cone angle is brought to the seal face of seal structure which is conveniently to assembly and disassembly. After the sealing principle analysis and stress calculation of graphite ring which adopt the cone angle, the cone angle increases the radial force of seal structure and improves the seal effect. The stress analysis result shows the seal structure strength satisfies the regulation requirement. The cold and hot function test results shows the sealing effect is good, and the design requirement is satisfied. (authors)

Development of sealing plug for sweep gas line

International Nuclear Information System (INIS)

Kikuchi, Taiji; Yamada, Hirokazu; Saitoh, Takashi; Nakamichi, Masaru; Tsuchiya, Kunihiko; Kawamura, Hiroshi

2004-03-01

On the irradiation capsule for neutron irradiation test of the tritium breeder, the sealing plug is necessary to prevent a leak of tritium gas when the tritium breeder is picked up from the irradiation capsule after irradiation test. However, the general valve and plug cannot apply to sealing of the sweep gas line because of the following factors, the neutron irradiation effect, limited space in the irradiation capsule, high sealing efficiency, simple method and operation for control. Therefore, the sealing plug for sweep gas line has to be developed. This paper reports the development of the sealing plug for sweep gas line and the operating procedure of the sealing plug in the irradiation capsule. (author)

2007 NASA Seal/Secondary Air System Workshop. Volume 1

Science.gov (United States)

Steinetz, Bruce M.; Hendricks, Robert C.; Delgado, Irebert

2008-01-01

The 2007 NASA Seal/Secondary Air System workshop covered the following topics: (i) Overview of NASA's new Orion project aimed at developing a new spacecraft that will fare astronauts to the International Space Station, the Moon, Mars, and beyond; (ii) Overview of NASA's fundamental aeronautics technology project; (iii) Overview of NASA Glenn s seal project aimed at developing advanced seals for NASA's turbomachinery, space, and reentry vehicle needs; (iv) Reviews of NASA prime contractor, vendor, and university advanced sealing concepts, test results, experimental facilities, and numerical predictions; and (v) Reviews of material development programs relevant to advanced seals development. Turbine engine studies have shown that reducing seal leakage as well as high-pressure turbine (HPT) blade tip clearances will reduce fuel burn, lower emissions, retain exhaust gas temperature margin, and increase range. Turbine seal development topics covered include a method for fast-acting HPT blade tip clearance control, noncontacting low-leakage seals, intershaft seals, and a review of engine seal performance requirements for current and future Army engine platforms.

Comparison of correlation algorithms for identifying ultrasonic seals

International Nuclear Information System (INIS)

Beer, C.L.; McKenzie, J.M.

1991-01-01

Ultrasonic seals are used on reactor fuel assemblies for international safeguards applications. The seals are read by a Seal Pattern Reader to obtain a discrete digital signature that is unique to each seal. The signature is used to determine the identity and integrity of the seals such that accountability and integrity of the nuclear fuel assemblies can be addressed. A correlation coefficient is calculated between the signature obtained at the time of inspection and a stored reference signature, yielding a number between negative one and one. Numbers close to one indicate a high probability that the two signatures represent the same seal. Data from two seals were studied, the Atomic Energy of Canada Limited Random Coil (ARC) seal and the JRC-Ispra VAK-III seal. Currently, correlation coefficients are obtained using data in the time or spatial domain, respectively. An approach is proposed in which the correlation coefficients are obtained from the Fourier transforms of the data. This paper reports that the objective of the study was to perform independent experiments on available ARC and VAK-III data to determine the advantages, if any, of transforming the data to the frequency spectrum prior to performing the correlation calculation. The results indicate definite advantages can be obtained

Effect of sealing on the morphology of anodized aluminum oxide

International Nuclear Information System (INIS)

Hu, Naiping; Dong, Xuecheng; He, Xueying; Browning, James F.; Schaefer, Dale W.

2015-01-01

Highlights: • We explored structural change of anodizing aluminum oxide induced by sealing. • All sealing methods decrease pore size as shown by X-ray/neutron scattering. • Cold sealing and hot water sealing do not alter the aluminum oxide framework. • Hot nickel acetate sealing both fills the pores and deposits on air oxide interface. • Samples with hot nickel acetate sealing outperform other sealing methods. - Abstract: Ultra-small angle X-ray scattering (USAXS), small-angle neutron scattering (SANS), X-ray reflectometry (XRR) and neutron reflectometry (NR) were used to probe structure evolution induced by sealing of anodized aluminum. While cold nickel acetate sealing and hot-water sealing decrease pore size, these methods do not alter the cylindrical porous framework of the anodic aluminum oxide layer. Hot nickel acetate both fills the pores and deposits on the air surface (air–oxide interface), leading to low porosity and small mean pore radius (39 Å). Electrochemical impedance spectroscopy and direct current polarization show that samples sealed by hot nickel acetate outperform samples sealed by other sealing methods

Ergonomics and safety of manual bag sealing.

NARCIS (Netherlands)

Groot, M.D. de; Bosch, T.; Eikhout, S.M.; Vink, P.

2005-01-01

A variety of seals is used to close bags. Each seal has advantages and disadvantages. For shop assistants sealing bags could be a repetitive physically demanding action. Opening and closing the bags again can cause some discomfort or annoyance for consumers. Besides, it is an activity which can

Initial field testing definition of subsurface sealing and backfilling tests in unsaturated tuff; Yucca Mountain Site Characterization Project

Energy Technology Data Exchange (ETDEWEB)

Fernandez, J.A. [Sandia National Labs., Albuquerque, NM (United States); Case, J.B.; Tyburski, J.R. [I. T. Corp., Albuquerque, NM (United States)

1993-05-01

This report contains an initial definition of the field tests proposed for the Yucca Mountain Project repository sealing program. The tests are intended to resolve various performance and emplacement concerns. Examples of concerns to be addressed include achieving selected hydrologic and structural requirements for seals, removing portions of the shaft liner, excavating keyways, emplacing cementitious and earthen seals, reducing the impact of fines on the hydraulic conductivity of fractures, efficient grouting of fracture zones, sealing of exploratory boreholes, and controlling the flow of water by using engineered designs. Ten discrete tests are proposed to address these and other concerns. These tests are divided into two groups: Seal component tests and performance confirmation tests. The seal component tests are thorough small-scale in situ tests, the intermediate-scale borehole seal tests, the fracture grouting tests, the surface backfill tests, and the grouted rock mass tests. The seal system tests are the seepage control tests, the backfill tests, the bulkhead test in the Calico Hills unit, the large-scale shaft seal and shaft fill tests, and the remote borehole sealing tests. The tests are proposed to be performed in six discrete areas, including welded and non-welded environments, primarily located outside the potential repository area. The final selection of sealing tests will depend on the nature of the geologic and hydrologic conditions encountered during the development of the Exploratory Studies Facility and detailed numerical analyses. Tests are likely to be performed both before and after License Application.

Interaction between clay-based shaft seal components and crystalline host rock

International Nuclear Information System (INIS)

Priyanto, D.; Dixon, D.; Man, A.

2010-01-01

at the URL at the shaft seal location. In order to provide relevant boundary conditions to numerical modelling, the in situ stress and pore water pressure measurements at the URL are to be used to determine H-M boundary conditions of the shaft seal numerical simulation. In this numerical model, the FZ included in the modelling scenario will be located at 250 m depth and the repository will be located at a depth of 500 m. As a result of the considerable distance of the shaft seal from the repository horizon and the expectation that the hydro-mechanical (H-M) evolution will largely occur before any temperature perturbations occur at the shaft location, the assumption is made that the shaft seal is in an isothermal condition. The FZ is assumed to be 4-m-thick (i.e. similar to the URL conditions) and perfectly horizontal. These allow H-M simulation within a smaller domain, using a 2D-axisymmetric model. H-M properties of each shaft seal component (bentonite-sand (BS) and dense backfill (DBF), moderately fractured rock (MFR), and concrete seals (CS)) of the shaft seal are required in this numerical modelling. The BS is the same type used in the URL shaft seal. The BS is composed of 40% bentonite and 60% sand, compacted in situ with target dry density of 1.80 ± 0.05 Mg/m 3 and gravimetric water content of 12-14%. The DBF in the shaft seal model is a mixture of glacial lake clay, crushed host rock and bentonite clay, installed at high dry density by in situ compaction. An elastoplastic model for unsaturated clay is used to describe the mechanical behaviour of these clay-based seal components. Priyanto et al. (2009) discussed the calibration of the H-M constitutive model parameters based on the results of various laboratory test results of the BS in Canada. These parameters will be used to describe H-M behaviour of the clay-based sealing components (BS and DBF). Compared to the clay components (BS and DBF), the unfractured rock and concrete components are much stiffer and

Clinical efficacy of artificial skin combined with vacuum sealing drainage in treating large-area skin defects

Institute of Scientific and Technical Information of China (English)

TANG Jin; GUO Wei-chun; YU Ling; ZHAO Sheng-hao

2010-01-01

Objective: To observe the clinical efficacy of artificial skin combined with vacuum sealing drainage (VSD) in treating large-area skin defects.Methods: Totally 18 patients with skin defects, treated with artificial skin combined with VSD from September 2008to May 2009 in our hospital, were retrospectively analyzed in this study. There were 15 males and 3 females, aged 7-66years, 34.3 years on average. Among them, 10 cases had skin laceration caused by traffic accidents (7 with open fractures), 1 mangled injury, 1 blast injury, 1 stump infection combined with skin defects after amputation and 5 heel ulcers.Results: All skin grafts in 16 cases survived after being controlled by VSD for one time. For the rest 2 patients,one with skin avulsion on the left foot was given median thickness skin grafts after three times of VSD, the other with open fractures in the left tibia and fibula caused by a traffic accident was given free flap transplantation. Skin grafts of both patients survived, with normal color and rich blood supply.Conclusion: Skin grafting in conjunction with artificial skin and VSD is much more effective than traditional dressing treatment and worth wide application in clinic.

Cannula has lip seal movingly coupled to proximal section, to facilitate relative movement of instrument shaft between seal and proximal section and to maintain sealing engagement between shaft and proximal portion

OpenAIRE

Bonadio, Frank; Vaugh, Trevor

2007-01-01

The cannula (1) has an instrument insertion section (3) and a tube (2) with an access channel (7) for extension of an instrument. A lip seal (4) movingly couples to a proximal section to engage with an instrument shaft (5). The seal facilitates a lateral movement of the instrument, and maintains the sealing engagement between the seal and the instrument shaft. A coupling portion made of gelatinous elastomeric material with plasticizer consisting of naturally derived oils, synthetic oils and l...

Turbocharger with variable nozzle having vane sealing surfaces

Science.gov (United States)

Arnold, Philippe [Hennecourt, FR; Petitjean, Dominique [Julienrupt, FR; Ruquart, Anthony [Thaon les Vosges, FR; Dupont, Guillaume [Thaon les Vosges, FR; Jeckel, Denis [Thaon les Vosges, FR

2011-11-15

A variable nozzle for a turbocharger includes a plurality of vanes rotatably mounted on a nozzle ring and disposed in a nozzle flow path defined between the nozzle ring and an opposite nozzle wall. Either or both of the faces of the nozzle ring and nozzle wall include(s) at least one step that defines sealing surfaces positioned to be substantially abutted by airfoil surfaces of the vanes in the closed position of the vanes and to be spaced from the airfoil surfaces in positions other than the closed position. This substantial abutment between the airfoil surfaces and the sealing surfaces serves to substantially prevent exhaust gas from leaking past the ends of the airfoil portions. At the same time, clearances between the nozzle ring face and the end faces of the airfoil portions can be sufficiently large to prevent binding of the vanes under all operating conditions.

Dampers for Stationary Labyrinth Seals

Science.gov (United States)

El-Aini, Yehia; Mitchell, William; Roberts, Lawrence; Montgomery, Stuart; Davis, Gary

2011-01-01

Vibration dampers have been invented that are incorporated as components within the stationary labyrinth seal assembly. These dampers are intended to supplement other vibration-suppressing features of labyrinth seals in order to reduce the incidence of high-cycle-fatigue failures, which have been known to occur in the severe vibratory environments of jet engines and turbopumps in which labyrinth seals are typically used. A vibration damper of this type includes several leaf springs and/or a number of metallic particles (shot) all held in an annular seal cavity by a retaining ring. The leaf springs are made of a spring steel alloy chosen, in conjunction with design parameters, to maintain sufficient preload to ensure effectiveness of damping at desired operating temperatures. The cavity is vented via a small radial gap between the retaining ring and seal housing. The damping mechanism is complex. In the case of leaf springs, the mechanism is mainly friction in the slippage between the seal housing and individual dampers. In the case of a damper that contains shot, the damping mechanism includes contributions from friction between individual particles, friction between particles and cavity walls, and dissipation of kinetic energy of impact. The basic concept of particle/shot vibration dampers has been published previously; what is new here is the use of such dampers to suppress traveling-wave vibrations in labyrinth seals. Damping effectiveness depends on many parameters, including, but not limited to, coefficient of friction, mode shape, and frequency and amplitude of vibrational modes. In tests, preloads of the order of 6 to 15 lb (2.72 to 6.8 kilograms) per spring damper were demonstrated to provide adequate damping levels. Effectiveness of shot damping of vibrations having amplitudes from 20 to 200 times normal terrestrial gravitational acceleration (196 to 1,960 meters per square second) and frequencies up to 12 kHz was demonstrated for shot sizes from 0.032 to

"Annotated Lectures": Student-Instructor Interaction in Large-Scale Global Education

Directory of Open Access Journals (Sweden)

Roger Diehl

2009-10-01

Full Text Available We describe an "Annotated Lectures" system, which will be used in a global virtual teaching and student collaboration event on embodied intelligence presented by the University of Zurich. The lectures will be broadcasted via video-conference to lecture halls of different universities around the globe. Among other collaboration features, an "Annotated Lectures" system will be implemented in a 3D collaborative virtual environment and used by the participating students to make annotations to the video-recorded lectures, which will be sent to and answered by their supervisors, and forwarded to the lecturers in an aggregated way. The "Annotated Lectures" system aims to overcome the issues of limited studentinstructor interaction in large-scale education, and to foster an intercultural and multidisciplinary discourse among students who review the lectures in a group. After presenting the concept of the "Annotated Lectures" system, we discuss a prototype version including a description of the technical components and its expected benefit for large-scale global education.

The (in)effectiveness of Global Land Policies on Large-Scale Land Acquisition

NARCIS (Netherlands)

Verhoog, S.M.

2014-01-01

Due to current crises, large-scale land acquisition (LSLA) is becoming a topic of growing concern. Public data from the ‘Land Matrix Global Observatory’ project (Land Matrix 2014a) demonstrates that since 2000, 1,664 large-scale land transactions in low- and middle-income countries were reported,

Ductile alloys for sealing modular component interfaces

Science.gov (United States)

Marra, John J.; Wessell, Brian J.; James, Allister W.; Marsh, Jan H.; Gear, Paul J.

2017-08-08

A vane assembly (10) having: an airfoil (12) and a shroud (14) held together without metallurgical bonding there between; a channel (22) disposed circumferentially about the airfoil (12), between the airfoil (12) and the shroud (14); and a seal (20) disposed in the channel (22), wherein during operation of a turbine engine having the vane assembly (10) the seal (20) has a sufficient ductility such that a force generated on the seal (20) resulting from relative movement of the airfoil (12) and the shroud (14) is sufficient to plastically deform the seal (20).

Ceramic-glass-metal seal by microwave heating

Science.gov (United States)

Meek, Thomas T.; Blake, Rodger D.

1985-01-01

A method for producing a ceramic-glass-metal seal by microwaving mixes a slurry of glass sealing material and coupling agent and applies same to ceramic and metal workpieces. The slurry and workpieces are then insulated and microwaved at a power, time and frequency sufficient to cause a liquid phase reaction in the slurry. The reaction of the glass sealing material forms a chemically different seal than that which would be formed by conventional heating because it is formed by diffusion rather than by wetting of the reactants.

Bingham Sealing and Application in Vacuum Clamping

Science.gov (United States)

Yao, S. M.; Teo, Wee Kin; Geng, Zunmin; Turner, Sam; Ridgway, Keith

2011-12-01

Vacuum clamping is extensively used in shell machining. In this paper a Bingham Sealing (BS) is presented and formulized based on Bingham plastic performance. The sealing capability of BS is evaluated in various cases. A new Bingham plastic is developed and the yield stress is measured. The performances of "O"ring sealing and BS with the developed Bingham plastic are compared to the static experiment. In this experiment the same vacuum is achieved and the distortion of the blade with BS is better than that with "O" ring sealing.

Bingham Sealing and Application in Vacuum Clamping

International Nuclear Information System (INIS)

Yao, S M; Teo, Wee Kin; Geng Zunmin; Turner, Sam; Ridgway, Keith

2011-01-01

Vacuum clamping is extensively used in shell machining. In this paper a Bingham Sealing (BS) is presented and formulized based on Bingham plastic performance. The sealing capability of BS is evaluated in various cases. A new Bingham plastic is developed and the yield stress is measured. The performances of Or ing sealing and BS with the developed Bingham plastic are compared to the static experiment. In this experiment the same vacuum is achieved and the distortion of the blade with BS is better than that with 'O' ring sealing.

HMSRP Hawaiian Monk Seal Crittercam video

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This project investigates foraging behavior of Hawaiian monk seals by conducting telemetry studies. During these studies, live seals are instrumented with dive...

Global Well-Posedness of the Boltzmann Equation with Large Amplitude Initial Data

Science.gov (United States)

Duan, Renjun; Huang, Feimin; Wang, Yong; Yang, Tong

2017-07-01

The global well-posedness of the Boltzmann equation with initial data of large amplitude has remained a long-standing open problem. In this paper, by developing a new {L^∞_xL^1v\\cap L^∞_{x,v}} approach, we prove the global existence and uniqueness of mild solutions to the Boltzmann equation in the whole space or torus for a class of initial data with bounded velocity-weighted {L^∞} norm under some smallness condition on the {L^1_xL^∞_v} norm as well as defect mass, energy and entropy so that the initial data allow large amplitude oscillations. Both the hard and soft potentials with angular cut-off are considered, and the large time behavior of solutions in the {L^∞_{x,v}} norm with explicit rates of convergence are also studied.

Leak detection of KNI seals

International Nuclear Information System (INIS)

Baranyai, G.; Peter, A.; Windberg, P.

1990-03-01

In Unit 3 and 4 of the Paks Nuclear Power Plant, Hungary, KNI type seals are used as lead-throughs with conical nickel sealing rings. Their failure can be critical for the operation of the reactor. An Acoustical Leak Detection System (ALDS) was constructed and tested for the operational testing of the seals. Some individual papers are presented in this collection on the calibration and testing of the ALDS intended to be placed on the top of the reactor vessels. The papers include simulation measurements of Unit 3 of NPP, laboratory experiments, evaluation of measurements, and further development needs with the ALDS. (R.P.) 50 figs.; 19 tabs

Unification of reactor elastomeric sealing based on material

International Nuclear Information System (INIS)

Sinha, N.K.; Raj, Baldev

2012-01-01

The unification of elastomeric sealing applications of Indian nuclear reactors based on a few qualified fluoroelastomer/perfluoroelastomer compounds and standardized approaches for finite element analysis (FEA) based design, manufacturing process and antifriction coatings is discussed. It is shown that the advance polymer architecture based Viton ® formulation developed for inflatable seals of 500 MWe Prototype Fast Breeder Reactor (PFBR) and its four basic variations can encompass other sealing applications of PFBR with minimum additional efforts on development and validation. Changing the blend ratio of Viton ® GBL 200S and 600S in inflatable seal formulation could extend its use to Pressurized Heavy Water Reactors (PHWRs). The higher operating temperature of Advanced Heavy Water Reactor (AHWR) seals expands the choice to perfluoroelastomers. FEA based on plane-strain/axisymmetric modeling (with Mooney–Rivlin as the basic constitutive model), seal manufacture by cold feed extrusion and injection molding as well as plasma Teflon-like coating belonging to two variations obtained from the development of inflatable seals provide the necessary standardization for unification. The gains in simplification of design, development and operation of seals along with the enhancements of safety and reliability are expected to be substantial.

Machine Vision Inspection of Polymeric Traypack Seal Areas

National Research Council Canada - National Science Library

Coburn, John

2002-01-01

.... Since entrapped matter can lead to open seals, defects, and seal anomalies, a method of measurement for seal area contamination is useful in quantifying effects of filler changes, line speeds, and product formulations...

Global hypomethylation is an independent prognostic factor in diffuse large B cell lymphoma

DEFF Research Database (Denmark)

Wedge, Eileen; Hansen, Jakob Werner; Garde, Christian

2017-01-01

Global hypomethylation has been linked to disease progression in several cancers, but has not been reported for Diffuse Large B Cell Lymphoma (DLBCL). This study aimed to assess global methylation in DLBCL and describe its prognostic value. Mean LINE1 methylation, a validated surrogate measure...... for global methylation, was measured in DNA from 67 tumor biopsies. Additionally, cell-free circulating DNA (cfDNA) in plasma samples from 74 patients was tested to assess the feasibility of global hypomethylation as a biomarker in liquid biopsies. LINE1 methylation was assessed using a commercially...

Global Bedload Flux Modeling and Analysis in Large Rivers

Science.gov (United States)

Islam, M. T.; Cohen, S.; Syvitski, J. P.

2017-12-01

Proper sediment transport quantification has long been an area of interest for both scientists and engineers in the fields of geomorphology, and management of rivers and coastal waters. Bedload flux is important for monitoring water quality and for sustainable development of coastal and marine bioservices. Bedload measurements, especially for large rivers, is extremely scarce across time, and many rivers have never been monitored. Bedload measurements in rivers, is particularly acute in developing countries where changes in sediment yields is high. The paucity of bedload measurements is the result of 1) the nature of the problem (large spatial and temporal uncertainties), and 2) field costs including the time-consuming nature of the measurement procedures (repeated bedform migration tracking, bedload samplers). Here we present a first of its kind methodology for calculating bedload in large global rivers (basins are >1,000 km. Evaluation of model skill is based on 113 bedload measurements. The model predictions are compared with an empirical model developed from the observational dataset in an attempt to evaluate the differences between a physically-based numerical model and a lumped relationship between bedload flux and fluvial and basin parameters (e.g., discharge, drainage area, lithology). The initial study success opens up various applications to global fluvial geomorphology (e.g. including the relationship between suspended sediment (wash load) and bedload). Simulated results with known uncertainties offers a new research product as a valuable resource for the whole scientific community.

Aging and lifetime prediction of O-ring seals

International Nuclear Information System (INIS)

Koemmling, Anja

2017-01-01

In some applications, elastomer seals have to remain leak tight over extended time periods (up to several decades) as an exchange of the seals is not practical. Therefore, it is necessary to be able to predict the lifetime of such seals reliably. For this reason, ageing experiments with O-rings and sheets based on hydrogenated acrylonitrile butadiene rubber (HNBR), ethylene propylene diene rubber (EPDM) and fluorocarbon rubber (FKM) were performed over up to two years at different temperatures. For investigating the changes of material properties during ageing, measurements of i.a. hardness and tensile behaviour as well as dynamic-mechanical and thermogravimetric analyses were conducted. For assessing the relaxation and recovery behaviour of the ageing seals, compression stress relaxation and compression set experiments were performed. Furthermore, leakage rate was measured to detect seal failure. By examining the aged samples, both the property changes and the responsible degradation mechanisms were characterised. Additionally, the most suitable approach for lifetime predictions should be determined using the large database of results from different test methods performed at several ageing times and temperatures. This included identifying an end-of-lifetime criterion that correlates with leakage and thus seal failure. Regarding the property changes and degradation mechanisms of HNBR, a pronounced embrittlement was observed due to dominant crosslinking reactions during ageing. These also resulted in a decrease of oxygen permeability, leading to a reduction of the oxygen transport into the interior sample (mainly of the thicker O-rings). This resulted in diffusion-limited oxidation effects (DLO effects), meaning that the interior of the sample aged less strongly than regions close to the surface. During ageing of EPDM, both chain scission and crosslinking occurred, which became noticeable in deteriorated tensile properties and decreased compression force as well as

Implementation of multiple measures to improve reactor recirculation pump sealing performance in nuclear boiling water reactor service

Energy Technology Data Exchange (ETDEWEB)

Loenhout, Gerard van [Flowserve B.V., Etten-Leur (Netherlands). Nuclear Services and Solutions Engineering; Hurni, Juerg

2014-07-01

A modern reactor recirculation pump circulates a large volume of high temperature, very pure water from the reactor pressure vessel back to the core. A crucial technical problem with a recirculation pump, such as a mechanical seal indicating loss of sealing pressure, may result in a power station having to shut down for repair. The paper describes the sudden increase in stray current phenomenon leading to rapid and severe deterioration of the mechanical end face shaft seal in a reactor recirculation pump. This occurred after the installation of a variable frequency converter replacing the original motorgenerator set.

Implementation of multiple measures to improve reactor recirculation pump sealing performance in nuclear boiling water reactor service

International Nuclear Information System (INIS)

Loenhout, Gerard van; Hurni, Juerg

2014-01-01

A modern reactor recirculation pump circulates a large volume of high temperature, very pure water from the reactor pressure vessel back to the core. A crucial technical problem with a recirculation pump, such as a mechanical seal indicating loss of sealing pressure, may result in a power station having to shut down for repair. The paper describes the sudden increase in stray current phenomenon leading to rapid and severe deterioration of the mechanical end face shaft seal in a reactor recirculation pump. This occurred after the installation of a variable frequency converter replacing the original motorgenerator set.

Reactor coolant pump shaft seal behavior during station blackout

International Nuclear Information System (INIS)

Kittmer, C.A.; Wensel, R.G.; Rhodes, D.B.; Metcalfe, R.; Cotnam, B.M.; Gentili, H.; Mings, W.J.

1985-04-01

A testing program designed to provide fundamental information pertaining to the behavior of reactor coolant pump (RCP) shaft seals during a postulated nuclear power plant station blackout has been completed. One seal assembly, utilizing both hydrodynamic and hydrostatic types of seals, was modeled and tested. Extrusion tests were conducted to determine if seal materials could withstand predicted temperatures and pressures. A taper-face seal model was tested for seal stability under conditions when leaking water flashes to steam across the seal face. Test information was then used as the basis for a station blackout analysis. Test results indicate a potential problem with an elastomer material used for O-rings by a pump vendor; that vendor is considering a change in material specification. Test results also indicate a need for further research on the generic issue of RCP seal integrity and its possible consideration for designation as an unresolved safety issue

Cask systems development program seal technology

International Nuclear Information System (INIS)

Madsen, M.M.; Humphreys, D.L.; Edwards, K.R.

1991-01-01

General design or test performance requirements for radioactive materials (RAM) packages are specified in Title 10 of the US Code of Federal Regulations Part 71 (10 CFR 71). Seals that provide the containment system interface between the packaging body and the closure must function in both high- and low-temperature environments under dynamic and static conditions. Experiments were performed to characterize the performance of several seal materials at low temperatures. Helium leak tests on face seals were used to compare the materials. Materials tested include butyl, neoprene, ethylene propylene, fluorosilicone, silicone, Eypel, Kalrez, Teflon, fluorocarbon, and Teflon/silicone composites. Results show that the seal materials tested, with the exception of silicone S613-60, are not leak tight (1 x 10 -7 std cm 3 /s) at manufacturer low-temperature ratings

High pressure thimble/guide tube seal fitting with built-in low pressure seal especially suitable for facilitated and more efficient nuclear reactor refueling service

International Nuclear Information System (INIS)

Bhatt, P.N.; Blaushield, R.M.

1991-01-01

This patent describes a HP/LP seal arrangement for an elongated guide tube and an elongated thimble disposed therein. The guide tube and thimble extending outwardly from the core of a nuclear reactor to a seal table where the guide tube is welded to the seal table to provide a high pressure seal relative thereto. It comprises: a tubular seal fitting disposed in alignment with the guide tube with the thimble extending therethrough on the low pressure side of the seal table; first high pressure sealing means coupling one end of the fitting to an end of the guide tube to prevent leakage from within the guide tube; inwardly facing thread means disposed adjacent the other and outer end of the seal fitting; a nut having an opening through which the thimble extends and further having outwardly facing threading in mating engagement with the fitting thread means; the fitting having a seal seat spaced longitudinally inwardly from the thread means and facing the fitting outer end and further disposed annularly about the inner surface of the fitting; deformable ring seal means; second releasable high pressure sealing means coupling the thimble to the outer end portion of the guide tube

Seal for an object containing nuclear fuel

International Nuclear Information System (INIS)

Scheuerpflug, W.; Nentwich, D.

1977-01-01

This seal which cannot be counterfeited, specially for sealing nuclear objects, e.g. fuel rods, not only makes any damage which has taken place obvious, but makes identification according to a key possible. For this purpose a minimum number of 'particles' or small bodies, which are identical but of different permeability, are fixed inside a short tube during 'loading' of the seal in a certain or an accidental sequence. The sequence of the spheres, which represents a key, can only be determined by special electromagnetic measuring equipment. On first opening the seal, this key sequence is irrevocably destroyed. (HP) [de

Properties of Sealing Materials in Groundwater Wells

DEFF Research Database (Denmark)

Köser, Claus

pellets as sealing material in groundwater wells. The way and the pattern, in which bentonite pellets are deposited, have been shown to have an effect on the swelling pressure of the bentonite seal. During the transport phase of pellets from the terrain to a given sedimentation depth, a sorting process......) into densities for clay/water systems has been developed. This method has successfully been used to evaluate e.g., macroporosity, homogenization of the bentonite seal during the hydration of water, hydraulic conductivity and the creation of channels in the bentonite seals. Based on the results obtained...

Sealing of ceramic SOFC-components with glass seals; Fuegen von keramischen Komponenten der Hochtemperatur-Brennstoffzellen mittels Glas- und Glaskeramikloten

Energy Technology Data Exchange (ETDEWEB)

Schillig, Cora

2012-07-10

The solid oxide fuel cell (SOFC) converts chemical energy of a fuel directly into electrical energy. However, for the implementation of SOFC-technology in competition to conventional power plants costs have to be reduced. The use of an alternative tubular cell design without closed end would allow reducing costs during cell manufacturing. However, this change in design makes a gastight sealing inside the generator near the gas inlet necessary. Different ceramic materials with varying coefficients of thermal expansion have to be sealed gastight and electrical insulating at temperatures between 850 C and 1000 C to prevent the gases from mixing and an electrical shortcut between the cells. This work comprises analysis of commercially available glass and glass-ceramic systems manufactured by Schott Electronic Packaging, Areva T and D and Ferro Corporation. Additionally new developed sealing glass and glass-ceramic systems were investigated and all systems were characterized fundamentally for the use as sealing material in SOFC generators. Therefore different test assemblies and series were conducted. Essential characteristics of a suitable sealing system are a thermal expansion coefficient between 9,5 and 12 . 10{sup -6}K{sup -1}, a viscosity in the range between 10{sup 4} to 10{sup 6} dPa{sup *}s and a wetting angle smaller than 90 during the sealing process. Also unwanted chemical side reactions between the sealing partners must be prevented, because a change in the phase composition or the creation of new phases in the sealing material could endanger the stability of the seal. Heat cycles, particularly those during generator operation, cause deterioration of the sealing material and subsequent reduction in its ability to prevent mixing of the gases. Sealant leaks can drastically impact efficiency of the generator. In order to ensure optimum operation low leak rates around 2,3 . 10{sup -4} mbar l/sec/cm{sup 2} must be maintained. Especially glass and glass

Replacement of nickel sealing rings by expanded graphite sealing rings -upgrading of SG primary collector flange connection

Energy Technology Data Exchange (ETDEWEB)

Cikryt, F.; Bednarek, L.; Kusyn, L. [Vitkovice, Ostrava (Switzerland)

1997-12-31

One of the most loaded parts of a steam generator of VVER 440 MW type are the bolts and thread holes of the primary collector cover sealing set. The strength calculations and tensometric measurings performed during operation proved the high degree of a load on the bolts. The conditions of the stress limitation are not met in some cases according to the pertinent standards. The untightnesses at nickel rings occurred during putting the units of Jaslovske Bohunice and Dukovany nuclear power stations into operation. With regard to improve the reliability, the producer has taken measures to improve the quality of the rings and users have introduced more strict regulations for bolts tightening. Due to these measures the high reliability of the set has been obtained from point of view of the tightness, but substantial reduction of bolts and holes threads loading have not been obtained. Several years operation experience proved relatively low service of bolts, damage of thread holes and sealing grooves. As the degree of mechanical load is one of the vital parameters influencing the damage of sealing set, in 1996 we started with the works aimed at a possibility of nickel sealing rings replacement for a more modern type of sealing which assure the higher reliability and service life of the individual part of sealing set under the reduced load.

Replacement of nickel sealing rings by expanded graphite sealing rings -upgrading of SG primary collector flange connection

Energy Technology Data Exchange (ETDEWEB)

Cikryt, F; Bednarek, L; Kusyn, L [Vitkovice, Ostrava (Switzerland)

1998-12-31

One of the most loaded parts of a steam generator of VVER 440 MW type are the bolts and thread holes of the primary collector cover sealing set. The strength calculations and tensometric measurings performed during operation proved the high degree of a load on the bolts. The conditions of the stress limitation are not met in some cases according to the pertinent standards. The untightnesses at nickel rings occurred during putting the units of Jaslovske Bohunice and Dukovany nuclear power stations into operation. With regard to improve the reliability, the producer has taken measures to improve the quality of the rings and users have introduced more strict regulations for bolts tightening. Due to these measures the high reliability of the set has been obtained from point of view of the tightness, but substantial reduction of bolts and holes threads loading have not been obtained. Several years operation experience proved relatively low service of bolts, damage of thread holes and sealing grooves. As the degree of mechanical load is one of the vital parameters influencing the damage of sealing set, in 1996 we started with the works aimed at a possibility of nickel sealing rings replacement for a more modern type of sealing which assure the higher reliability and service life of the individual part of sealing set under the reduced load.

Application of radioisotope technique for investigation of pumps seals

International Nuclear Information System (INIS)

Antoszewski, B.; Zorawska, A.

1988-01-01

Radioisotope method of measuring the wear of rings of the face mechanical seals, bush in soft seals, and leakage in double mechanical seals is described. The examples are given. It is found that radioisotope technique can be used for investigation of the seals. (author)

Legacy HMSRP Hawaiian Monk Seals Observers

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This data set documents observers that have collected monk seal data as part of the ongoing monk seal population assessment efforts by PSD personnel and cooperating...

HMSRP Hawaiian Monk Seal Entanglement data

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The data set contains records of all entanglements of Hawaiian monk seals in marine debris. The data set comprises records of seals entangled by derelict fishing...

Sealed source peer review plan

International Nuclear Information System (INIS)

Feldman, Alexander; Leonard, Lee; Burns, Ron

2009-01-01

Sealed sources are known quantities of radioactive materials that have been encapsulated in quantities that produce known radiation fields. Sealed sources have multiple uses ranging from instrument calibration sources to sources that produce radiation fields for experimental applications. The Off-Site Source Recovery (OSR) Project at Los Alamos National Laboratory (LANL), created in 1999, under the direction of the Waste Management Division of the U.S. Department of Energy (DOE) Albuquerque has been assigned the responsibility to recover and manage excess and unwanted radioactive sealed sources from the public and private sector. LANL intends to ship drums containing qualified sealed sources to the Waste Isolation Pilot Plant (WIPP) for disposal. Prior to shipping, these drums must be characterized with respect to radiological content and other parameters. The U. S. Environmental Protection Agency (EPA) requires that ten radionulcides be quantified and reported for every container of waste to be disposed in the WIPP. The methods traditionally approved by the EPA include non-destructive assay (NDA) in accordance with Appendix A of the Contact-Handled Transuranic Waste Acceptance Criteria for the Waste Isolation Pilot Plant (DOE, 2002) (CH WAC). However, because of the nature and pedigree of historical records for sealed sources and the technical infeasibility of performing NDA on these sources, LANL proposes to characterize the content of these waste drums using qualified existing radiological data in lieu of direct measurement. This plan describes the process and documentation requirements for the use of the peer review process to qualify existing data for sealed radiological sources in lieu of perfonning radioassay. The peer review process will be performed in accordance with criteria provided in 40 CFR (section) 194.22 which specifies the use of the NUREG 1297 guidelines. The plan defines the management approach, resources, schedule, and technical requirements

Molybdenum sealing glass-ceramic composition

International Nuclear Information System (INIS)

Eagan, R.J.

1976-01-01

A glass-ceramic composition is described having low hydrogen and helium permeability properties, along with high fracture strength, and a thermal coefficient of expansion similar to that of molybdenum. The composition is adaptable for hermetically sealing to molybdenum at temperatures between 900 and about 950 0 C to form a hermetically sealed insulator body

Acoustic resonance spectroscopy intrinsic seals

International Nuclear Information System (INIS)

Olinger, C.T.; Burr, T.; Vnuk, D.R.

1994-01-01

We have begun to quantify the ability of acoustic resonance spectroscopy (ARS) to detect the removal and replacement of the lid of a simulated special nuclear materials drum. Conceptually, the acoustic spectrum of a container establishcs a baseline fingerprint, which we refer to as an intrinsic seal, for the container. Simply removing and replacing the lid changes some of the resonant frequencies because it is impossible to exactly duplicate all of the stress patterns between the lid and container. Preliminary qualitative results suggested that the ARS intrinsic seal could discriminate between cases where a lid has or has not been removed. The present work is directed at quantifying the utility of the ARS intrinsic seal technique, including the technique's sensitivity to ''nuisance'' effects, such as temperature swings, movement of the container, and placement of the transducers. These early quantitative tests support the potential of the ARS intrinsic seal application, but also reveal a possible sensitivity to nuisance effects that could limit environments or conditions under which the technique is effective

Pillow seal system at the BigRIPS separator

Energy Technology Data Exchange (ETDEWEB)

Tanaka, K., E-mail: ktanaka@riken.jp; Inabe, N.; Yoshida, K.; Kusaka, K.; Kubo, T.

2013-12-15

Highlights: • Pillow seal system has been installed for a high-intensity RI-beam facility at RIKEN. • It is aimed at facilitating remote maintenance under high residual radiation. • Local radiation shields are integrated with one of the pillow seals. • Pillow seals have been aligned to the beam axis within 1mm accuracy. • A leakage rate of 10{sup –9} Pa m{sup 3}/s has been achieved with our pillow seal system. -- Abstract: We have designed and installed a pillow seal system for the BigRIPS fragment separator at the RIKEN Radioactive Isotope Beam Factory (RIBF) to facilitate remote maintenance in a radioactive environment. The pillow seal system is a device to connect a vacuum chamber and a beam tube. It allows quick attachment and detachment of vacuum connections in the BigRIPS separator and consists of a double diaphragm with a differential pumping system. The leakage rate achieved with this system is as low as 10{sup –9} Pa m{sup 3}/s. We have also designed and installed a local radiation-shielding system, integrated with the pillow seal system, to protect the superconducting magnets and to reduce the heat load on the cryogenic system. We present an overview of the pillow seal and the local shielding systems.

Plastic profiled sealing element for household refrigeration appliances

Energy Technology Data Exchange (ETDEWEB)

Wunderlich, E; Robl, G

1988-12-28

A plastic profiled sealing element for household refrigeration appliances, such as freezers, refrigerators, and freezer compartments, includes a sealing bellows having a hose-shaped cross section. The sealing bellows is provided with two side walls and a covering wall, and is made of a plastic that has been set by means of a softener so as to be continuously flexible. Further, the profiled sealing element is provided with an anchor member made of a plastic of the same or different material hardness, with the sealing bellows and the anchor member being connected with one another to form a unit. The cross sections of the two side walls of the sealing bellows narrow as the side walls rise from the region of the connection of the side walls with the covering wall of the anchor member to approximately half the height of the sealing bellows, so that the side walls become increasingly thinner. Thereafter, the cross sections of the side walls increase again to the edges of the covering wall of the sealing bellows, until the side walls again reach approximately their initial cross sections. The side walls, on the one hand, and the covering wall, on the other hand, are kept flexible by means of softeners having different characteristics.

Dynamics of face seals for high speed turbomachinery

Science.gov (United States)

Leefe, Simon

1993-10-01

Face seals in rocket engine fuel and oxidizer turbopumps have been the subject of intense investigation for over 25 years. While advances have been made in the understanding of thin film lubrication between seal faces, valuable data has been produced on the friction and wear of material pairs in cryogenic environments; pioneering work has been done on the effect of lubricant phase change in seals, and many improvements have been made in mechanical seal design. Relatively superficial attention has been given to the vibrational dynamics of face seals in high-speed turbomachinery. BHR Group Ltd. (formerly BHRA) has recently completed the first stage of a study, commissioned by the European Space Agency, to investigate this area. This has involved the development of a two-dimensional adiabatic, turbulent lubrication model for thick gas film applications, the production of an integrated mathematical model of gas seal vibrational dynamics for thin film applications, implementation in software, the undertaking of an experimental program to validate software against variations in operating conditions and design variables, and suggestions for improved seal design.

HMSRP Hawaiian Monk Seal Handling Data

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains records for all handling and measurement of Hawaiian monk seals since 1981. Live seals are handled and measured during a variety of events...

Implementation of multiple measures to improve reactor recirculation pump sealing performance in nuclear boiling water reactor service

Energy Technology Data Exchange (ETDEWEB)

Loenhout, Gerard van [Flowserve B.V., Etten-Leur (Netherlands). Nuclear Services and Solutions Engineering; Hurni, Juerg

2015-05-15

A modern reactor recirculation pump circulates a large volume of high temperature, very pure water from the reactor pressure vessel back to the core by feeding into multiple stationary jet pumps inside the vessel. Together with the jet pumps, they allow station operators to vary coolant flow and variable pump speed provides the best and most stable reactor power control. A crucial technical problem with a recirculation pump, such as a mechanical seal indicating loss of sealing pressure, may result in a power station having to shut down for repair. This article describes the sudden increase in stray current phenomenon leading to rapid and severe deterioration of the mechanical end face shaft seal in a reactor recirculation pump. This occurred after the installation of a variable frequency converter replacing the original motor-generator set. This article will also discuss the 2,500 hour laboratory test results conducted under reactor recirculation pump sealing conditions using a newly developed seal face technology recently implemented to overcome challenges when sealing neutral, ultra-pure water. In addition, the article will describe the elaborate shaft grounding arrangement and the preliminary measurement results achieved in order to eliminate potential damages to both pump and mechanical seal.

Demographic, ecological, and physiological responses of ringed seals to an abrupt decline in sea ice availability.

Science.gov (United States)

Ferguson, Steven H; Young, Brent G; Yurkowski, David J; Anderson, Randi; Willing, Cornelia; Nielsen, Ole

2017-01-01

To assess whether demographic declines of Arctic species at the southern limit of their range will be gradual or punctuated, we compared large-scale environmental patterns including sea ice dynamics to ringed seal ( Pusa hispida ) reproduction, body condition, recruitment, and stress in Hudson Bay from 2003 to 2013. Aerial surveys suggested a gradual decline in seal density from 1995 to 2013, with the lowest density occurring in 2013. Body condition decreased and stress (cortisol) increased over time in relation to longer open water periods. The 2010 open water period in Hudson Bay coincided with extremes in large-scale atmospheric patterns (North Atlantic Oscillation, Arctic Oscillation, El Nino-Southern Oscillation) resulting in the earliest spring breakup and the latest ice formation on record. The warming event was coincident with high stress level, low ovulation rate, low pregnancy rate, few pups in the Inuit harvest, and observations of sick seals. Results provide evidence of changes in the condition of Arctic marine mammals in relation to climate mediated sea ice dynamics. We conclude that although negative demographic responses of Hudson Bay seals are occurring gradually with diminishing sea ice, a recent episodic environmental event played a significant role in a punctuated population decline.

Conjunctival flora of healthy and diseased eyes of grey seals (Halichoerus grypus): implications for treatment.

Science.gov (United States)

Fleming, M; Bexton, S

2016-07-23

Ocular pathology is relatively common in stranded seals admitted to wildlife rehabilitation hospitals. Some have pre-existing problems, while others develop eye problems in captivity, and in particular ulcerative keratitis, due to factors such as large prominent eyes, suboptimal water quality, trauma and infighting. Despite treatment, corneal ulcerations can rapidly progress to 'melting' ulcers with subsequent rupture of the globe. In this case series, 32 grey seals (Halichoerus grypus) had conjunctival swabs taken on admission to a UK wildlife hospital to identify ocular bacterial flora and nine had subsequent swabs taken after four weeks to see if this changed in captivity. Additionally, nine seals with ocular pathology were also swabbed. Although a wide range of bacteria were cultured on admission, the most common isolates were Gemella haemolysans, Escherichia coli and Clostridium perfringens All 'melting' ulcers were associated with Pseudomonas aeruginosa, which suggests this bacterial species may be significant in the pathogenesis of progressive stromal ulceration in grey seals. British Veterinary Association.

39 CFR 2.4 - Seal.

Science.gov (United States)

2010-07-01

... 39 Postal Service 1 2010-07-01 2010-07-01 false Seal. 2.4 Section 2.4 Postal Service UNITED STATES... Secretary of State, and is required by 39 U.S.C. 207 to be judicially noticed. The Seal shall be in the... description of the Postal Service emblem is described at 39 CFR 221.7. ...

Magnetic shaft seals prevent hazardous leakage from wastewater agitators

International Nuclear Information System (INIS)

Traino, F.A.

1985-01-01

The US Department of Energy's laboratory in Miamisburg, OH, operated by Monsanto Research Corporation, processes approximately 45,000 gallons per week of low-level radioactive wastewater to meet Federal Environmental Protection Agency quality standards. Preventing the spread of radioactive contamination throughout the operating area demands effective sealing of all process piping, valves, pumps, and agitators. Rotating shafts of pumps and agitators installed a the start of operations in 1947 were sealed by stuffing glands with graphite impregnated asbestos packing. These pumps proved to be unsatisfactory. In the mid-1970's, new process pumps with mechanical seals and some with magnetic drives were installed. Later, in January 1979, new agitator shaft drives with double tandem, spring-loaded mechanical seals were installed, maintenance of these pumps was costly. The agitator drive shafts were redesigned to accommodate magnetic seals of the type successfully used in blowers and vacuum/pressure pumps in other plant locations. One inherent advantage of the magnetic seal is that it operates with a face loading as much as 50% less than a conventional spring-loaded mechanical seal. The lower loading by a predetermined uniform magnetic force contributes to long face life. Other advantages include compactness, ease of assembly with only a few parts, and insensitivity to vibration. The magnetic shaft seals installed on the agitator shafts in February 1983 are still in service without any leakage or need for maintenance. Based on current operating data and a projected five-year meantime between failures, the estimated cost benefit of the magnetic seals over spring-loaded mechanical seals over spring-loaded mechanical seals will be $640 vs $2400 respectively per seal, with 60% less downtime for maintenance

Performances of Magnetic Fluid Seal and Application to Turbopumps

OpenAIRE

北洞, 貴也; 黒川, 淳一; 宮副, 雄貴; 林, 正悦

1994-01-01

A magnetic fluid shaft seal can achieve zero-leakage and operate stably against shaft vibration, but the sealing pressure is very low. In order to improve the pressure performance of a magnetic fluid seal and apply it to a turbopump, the seal pressure characteristics are studied theoretically and experimentally. The Poisson equation for magnetic vector potential is solved by FEM, and the seal performances are determined by use of the Bernoulli equation. The validity of the theory is confirmed...

Executive summary and general conclusions of the rock sealing project

International Nuclear Information System (INIS)

Pusch, R.

1992-06-01

The Stripa Rock Sealing Project logically followed the two first Stripa research phases dealing with canister-embedment and plugging of excavations in repositories. The major activities in the third phase were: * Literature review and interviews for setting the state of art of rock fracture sealing. * Pilot field and lab testing applying a new effective 'dynamic' grouting technique. * Development of a general grout flow theory. * Investigation of physical properties and longevity of major candidate grouts. * Performance of 4 large-scale tests. The literature study showed that longevity aspects limited the number of potentially useful grout materials to smectitic clay and cement. The pilot testing showed that fine-grained grouts can be effectively injected in relatively fine fractures. The theoretical work led to a general grout flow theory valid both for grouting at a constant, static pressure with non-Newtonian material properties, and for 'dynamic' injection with superimposed oscillations, yielding Newtonian material behavior. The investigation of physical properties of candidate grouts with respect to hydraulic conductivity, shear strength, sensitivity to mechanical strain, as well as to chemical stability, showed that effective sealing is offered, and that any rock can have its bulk conductivity reduced to about 10 -10 m/s. The field tests comprised investigation of excavation-induced disturbance and attempts to seal disturbed rock, and in separate tests, grouting of deposition holes and a natural fine-fracture zone. Considerable disturbance of nearfield rock by blasting and stress changes, yielding an increase in axial hydraulic conductivity by 3 and 1 order of magnitude, respectively, was documented but various factors, primarily debris in the fractures, made grouting of blasted rock ineffective. Narrow fractures in deposition holes and in a natural fracture zone were sealed rather effectively. (au)

Knife-edge seal for vacuum bagging

Science.gov (United States)

Rauschl, J. A.

1980-01-01

Cam actuated clamps pinch bagging material between long knife edge (mounted to clamps) and high temperature rubber cushion bonded to baseplate. No adhesive, tape, or sealing groove is needed to seal edge of bagging sheet against base plate.

Verification on reliability of diaphragm seal

International Nuclear Information System (INIS)

Ide, Hiroshi; Sakuta, Yoshiyuki; Hanawa, Yoshio; Tsuji, Tomoyuki; Tsuboi, Kazuaki; Nagao, Yoshiharu; Miyazawa, Masataka

2009-06-01

The main body of the JMTR is composed of reactor pressure vessel, core and reactor pool. At the bottom of the reactor pool, the Diaphragm-seal (2.6m outer diameter, 2m inner diameter, thickness 1.5mm) of the JMTR made of stainless steel is installed to prevent the water leak of the reactor pool and to absorb the expansion of the reactor pressure vessel due to pressure and temperature changes. In the long-term maintenance plans drawn up in 2004, it is required that the visual inspection for the diaphragm-seal should be carried out in 2007 and that the inspection should be carried out every around five-year. Therefore, prior to the refurbishment of the JMTR, the inspection device which is a deposition-collection apparatus with underwater-camera was developed, and the visual inspection was carried out to confirm the soundness of the diaphragm-seal. As a result, harmful flaws and/or corrosions were not inspected in the visual inspection, and the soundness of the diaphragm seal was confirmed. In future, the long-term integrity of the diaphragm-seal will could be achieved by conducting the periodic inspection. (author)

Magnetic vector field tag and seal

Science.gov (United States)

Johnston, Roger G.; Garcia, Anthony R.

2004-08-31

One or more magnets are placed in a container (preferably on objects inside the container) and the magnetic field strength and vector direction are measured with a magnetometer from at least one location near the container to provide the container with a magnetic vector field tag and seal. The location(s) of the magnetometer relative to the container are also noted. If the position of any magnet inside the container changes, then the measured vector fields at the these locations also change, indicating that the tag has been removed, the seal has broken, and therefore that the container and objects inside may have been tampered with. A hollow wheel with magnets inside may also provide a similar magnetic vector field tag and seal. As the wheel turns, the magnets tumble randomly inside, removing the tag and breaking the seal.

Radioactive material package seal tests

International Nuclear Information System (INIS)

Madsen, M.M.; Humphreys, D.L.; Edwards, K.R.

1990-01-01

General design or test performance requirements for radioactive materials (RAM) packages are specified in Title 10 of the US Code of Federal Regulations Part 71 (US Nuclear Regulatory Commission, 1983). The requirements for Type B packages provide a broad range of environments under which the system must contain the RAM without posing a threat to health or property. Seals that provide the containment system interface between the packaging body and the closure must function in both high- and low-temperature environments under dynamic and static conditions. A seal technology program, jointly funded by the US Department of Energy Office of Environmental Restoration and Waste Management (EM) and the Office of Civilian Radioactive Waste Management (OCRWM), was initiated at Sandia National Laboratories. Experiments were performed in this program to characterize the behavior of several static seal materials at low temperatures. Helium leak tests on face seals were used to compare the materials. Materials tested include butyl, neoprene, ethylene propylene, fluorosilicone, silicone, Eypel, Kalrez, Teflon, fluorocarbon, and Teflon/silicone composites. Because most elastomer O-ring applications are for hydraulic systems, manufacturer low-temperature ratings are based on methods that simulate this use. The seal materials tested in this program with a fixture similar to a RAM cask closure, with the exception of silicone S613-60, are not leak tight (1.0 x 10 -7 std cm 3 /s) at manufacturer low-temperature ratings. 8 refs., 3 figs., 1 tab

2005 NASA Seal/Secondary Air System Workshop, Volume 1

Science.gov (United States)

Steinetz, Bruce M. (Editor); Hendricks, Robert C. (Editor)

2006-01-01

The 2005 NASA Seal/Secondary Air System workshop covered the following topics: (i) Overview of NASA s new Exploration Initiative program aimed at exploring the Moon, Mars, and beyond; (ii) Overview of the NASA-sponsored Propulsion 21 Project; (iii) Overview of NASA Glenn s seal project aimed at developing advanced seals for NASA s turbomachinery, space, and reentry vehicle needs; (iv) Reviews of NASA prime contractor, vendor, and university advanced sealing concepts including tip clearance control, test results, experimental facilities, and numerical predictions; and (v) Reviews of material development programs relevant to advanced seals development. Turbine engine studies have shown that reducing high-pressure turbine (HPT) blade tip clearances will reduce fuel burn, lower emissions, retain exhaust gas temperature margin, and increase range. Several organizations presented development efforts aimed at developing faster clearance control systems and associated technology to meet future engine needs. The workshop also covered several programs NASA is funding to develop technologies for the Exploration Initiative and advanced reusable space vehicle technologies. NASA plans on developing an advanced docking and berthing system that would permit any vehicle to dock to any on-orbit station or vehicle. Seal technical challenges (including space environments, temperature variation, and seal-on-seal operation) as well as plans to develop the necessary "androgynous" seal technologies were reviewed. Researchers also reviewed tests completed for the shuttle main landing gear door seals.

IMOS: How seals are changing the way we monitor the Southern Ocean

Science.gov (United States)

Harcourt, R.; McMahon, C.; Jonsen, I.; Goldsworthy, S.; Hindell, M.; Hoenner, X.; Thums, M.

2016-02-01

IMOS (Integrated Marine Observing System) operates a wide range of ocean observing equipment throughout Australia's coastal waters and also the open oceans. This fully integrated, national system, covers physical, chemical and biological ocean sciences forming the basis for robust and informed study of the worlds oceans. Of particular interest in understanding global climate processes is the Southern Ocean (SO), but studying this remote region is difficult and most observations are collected during the short ice-free summer when the region is accessible. Through Winter and Spring it is extremely difficult to collect biophysical ocean information in the Southern Ocean. The importance of good observations from this region, the home of the Antarctic Circumpolar Current (ACC), the largest current system in the world, which connects water masses from the global ocean basins cannot be over emphasised. IMOS through the Australian Animal Tracking and Monitoring System (AATAMS) has made important inroads into collecting otherwise hard to obtain observations from the SO by using CTD bio-loggers to monitor coastal and oceanic movements of marine animals from the Australian mainland as far south as the Antarctic continent. In particular seals equipped with satellite-linked CTD tags have provided unique temporal and spatial coverage of the Southern Ocean. This includes extensive data from the Antarctic continental slope and shelf regions during the winter months, which is outside the conventional areas of Argo autonomous floats and ship-based studies. Over 75,000 temperature and salinity profiles have been collected from 20-140 °E, between the Kerguelen archipelago and Prydz Bay Antarctica. These data offer invaluable new insights into the water masses, oceanographic processes and provides a vital tool for oceanographers seeking to advance our understanding of this key component of the global ocean climate. Here we present an overview of the IMOS database of hydrographic (i

Identification of radioisotopes in bulks with disused sealed sources using a high performance portable spectrometer

International Nuclear Information System (INIS)

Zapata, Luis; Mallaupoma, Mario

2013-01-01

Sealed radioactive sources are widely used in many industrial applications, and after completing its useful life must be managed as radioactive wastes. One of the most common problems of disused sealed radioactive sources is that many times they lack proper identification and their certificates of manufacture. In that context, it is necessary to identify them, prior to any other management step. There are a number of techniques which can be used; however they are sometimes complex. This technical paper shows a simple way for its identification using the InSpector 1000 monitor which allows to know their energy spectra. These modern instruments and detectors have been obtained thanks to the Project Global Threat Reduction Initiative (Programa de Reduccion de Amenazas) between IPEN and the US DOE. (authors).

The southern elephant seal Mirounga leonina at Gough Island

African Journals Online (AJOL)

haul-out in December coincided with the elephant seal moulting season, the elephant seals were found on the vegetated areas whilst the majority of fur seals hauled out onto the boulder beach. No interactions between the two species were recorded. Potential predators of elephant seals, i.e. the killer whales Orcinus orca ...

Application of hydrophilic magnetic fluid to oil seal

Science.gov (United States)

Kim, Y. S.; Nakatsuka, K.; Fujita, T.; Atarashi, T.

1999-07-01

Bearing and gear are important components in machines. Lubricant for bearing or gear is usually confined in working space by rubber retainer or mechanical seal, and its lifetime which is determined by the friction wear of sealing material is important. In this report, the basic characteristics of magnetic fluid seal applied to lubricant retainer is studied. The fluid used for this purpose is ethyleneglycol-based magnetic fluid in which silica-coated iron particles are dispersed. The lubricant oil seal set consisting of six stages of pole piece and Nd-permanent magnets (4.0 Wb/m 2) in seal housing showed an excellent pressure resistance of 618 kPa under a rotating speed of 1800 rpm.

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

International Nuclear Information System (INIS)

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

1997-01-01

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

A morbillivirus causing mass mortality in seals.

Science.gov (United States)

Osterhaus, A

1989-12-01

During an outbreak of a serious apparently infectious disease among harbour seals (Phoca vitulina), which started in the Kattegat area in April 1988 and rapidly spread to the North sea, the Wadden sea and the Baltic sea, greater than 17,000 animals died within a period of eight months. In August 1988 it was realized that the clinical symptoms and pathological lesions were similar to those found in canine distemper: apart from general depression and fever, the animals suffered from severe respiratory, gastrointestinal and central nervous disease and a variety of viral, bacterial and parasitic infections were frequently encountered, suggesting a severe malfunctioning of the immune system. At different expert meetings, held in several of the countries involved, possible explanations for the deaths were not only attributed to an infectious agent, but also to effects of overpopulation and environmental pollution. Seroepizootiological studies and the failure of vaccination experiments suggested that a herpesvirus and a picornavirus, which had been isolated from dead seals at the beginning of the outbreak, were opportunistic infections occurring in animals suffering from another infection rather than being the primary cause of the outbreaks. Serological studies were then extended to other viruses of carnivores, known to cause similar symptoms. Screening of a large panel of seal sera from the Netherlands, Denmark, FRG, Sweden and the UK, collected before and during the outbreak, in a virus neutralization test for the presence of canine distemper virus (CDV) neutralizing antibodies, indicated that CDV or a closely related morbillivirus was the primary cause of the disease outbreak.(ABSTRACT TRUNCATED AT 250 WORDS)

Windpower and grey seals: An impact assessment of potential effects by sea-based windpower plants in a local seal population

International Nuclear Information System (INIS)

Sundberg, Jan; Soederman, Malin

2000-05-01

The impact of five sea-based wind power plants on two haulout sites for grey seals on southwestern Gotland, in the Baltic Sea, was analysed. Data on seal numbers was collected on a regular basis during the initial stages of the project from summer 1996, continuing during the building (autumn 1997) and running of the wind power plants (from spring 1998) until the end of June 1999. Additional observational data from earlier years was also available. Indications of lower occurrence and reduced number of seals in the area was found during periods of time in 1997 and 1998, times of construction and active running of the plants. However, no evidence on the wind power plants, per se, affecting the grey seals was found. Instead, several weather factors were found to affect the number of seals in the area, and periods of low occurrence and number of seals were more likely explained by i.e. unfavourable water levels and hard wind from certain directions. One important, short term, impact factor was however found. Human induced disturbances such as boat and helicopter traffic, some which were directly related to maintenance of the wind power plants, temporarily reduced number of seals and made them more restless. Disturbance thus constitutes a potential threat to seals. A shift from one to the other of the two haulout sites was also noted, a shift which likely is due to disturbances. Future guidelines are given, including some restrictions in movements near the haulout sites. Continued observations and studies are suggested if more off-shore wind power plants will be raised in the area. A call for more stringent use of environmental impact assessments is thus made. Also, suggestions on measures to be taken in order to reduce the effect of human related disturbances are made. In order to create sustainable conditions for a continued population of seals in the area and in order to create opportunities for a reestablishment of the grey seal in the southern Baltic region

Windpower and grey seals: An impact assessment of potential effects by sea-based windpower plants in a local seal population

Energy Technology Data Exchange (ETDEWEB)

Sundberg, Jan; Soederman, Malin [Uppsala Univ. (Sweden). Dept. of Animal Ecology

2000-05-01

The impact of five sea-based wind power plants on two haulout sites for grey seals on southwestern Gotland, in the Baltic Sea, was analysed. Data on seal numbers was collected on a regular basis during the initial stages of the project from summer 1996, continuing during the building (autumn 1997) and running of the wind power plants (from spring 1998) until the end of June 1999. Additional observational data from earlier years was also available. Indications of lower occurrence and reduced number of seals in the area was found during periods of time in 1997 and 1998, times of construction and active running of the plants. However, no evidence on the wind power plants, per se, affecting the grey seals was found. Instead, several weather factors were found to affect the number of seals in the area, and periods of low occurrence and number of seals were more likely explained by i.e. unfavourable water levels and hard wind from certain directions. One important, short term, impact factor was however found. Human induced disturbances such as boat and helicopter traffic, some which were directly related to maintenance of the wind power plants, temporarily reduced number of seals and made them more restless. Disturbance thus constitutes a potential threat to seals. A shift from one to the other of the two haulout sites was also noted, a shift which likely is due to disturbances. Future guidelines are given, including some restrictions in movements near the haulout sites. Continued observations and studies are suggested if more off-shore wind power plants will be raised in the area. A call for more stringent use of environmental impact assessments is thus made. Also, suggestions on measures to be taken in order to reduce the effect of human related disturbances are made. In order to create sustainable conditions for a continued population of seals in the area and in order to create opportunities for a reestablishment of the grey seal in the southern Baltic region

Seals, Concrete Anchors, and Connections

Science.gov (United States)

1989-02-01

caulking compounds, nonhardening extruded tapes, nonhardening mastics, strippable spray coatings, pressure sensitive tapes, gaskets, adhesives, fabrics...films, etc. Although all of these materials may provide a seal, care must be taken when selecting a sealing material as to its chemical and...gaskets have performed satisfactorily. Another factor to be considered in the selection of gasketing material is its compatibility with both the

Basis of property limits for inflatable seal fluoroelastomers

International Nuclear Information System (INIS)

Sinha, N.K.; Raj, Baldev

2012-01-01

Identification of a set of governing physico-mechanical properties for inflatable seals of Prototype Fast Breeder Reactor (PFBR) and specification of their limits is described based on operating requirements, design practices and results from seal development. The limits of tensile strength, elongation at break, hardness, tear strength, fluid compatibility, compression set and specific gravity defined for the Viton GBL 200S/600S based inflatable seal formulation provide a standardized framework for regular production of reactor seals and a streamlined approach for compounding, design, manufacture and quality control. This assures significant reduction of efforts during the envisaged unification of Fast Breeder Reactor sealing based on four variations of inflatable seal compound which could result in a universal design code apart from significant gains in safety, reliability and life. The property set has potential use in Pressurized Heavy Water Reactor and Advanced Heavy Water Reactor. Inclusion of factors such as batch-to-batch variations of compound properties and their reproducibility during laboratory measurements, hot tensile behavior of fluoroelastomer, long term ageing effects and the margin of safety at the end of seal design life ensures the utility of property set in attaining its intended objective.

Mechanical seal with textured sidewall

Energy Technology Data Exchange (ETDEWEB)

Khonsari, Michael M.; Xiao, Nian

2017-02-14

The present invention discloses a mating ring, a primary ring, and associated mechanical seal having superior heat transfer and wear characteristics. According to an exemplary embodiment of the present invention, one or more dimples are formed onto the cylindrical outer surface of a mating ring sidewall and/or a primary ring sidewall. A stationary mating ring for a mechanical seal assembly is disclosed. Such a mating ring comprises an annular body having a central axis and a sealing face, wherein a plurality of dimples are formed into the outer circumferential surface of the annular body such that the exposed circumferential surface area of the annular body is increased. The texture added to the sidewall of the mating ring yields superior heat transfer and wear characteristics.

Investigation of brush seals for application in steam turbines

International Nuclear Information System (INIS)

Zorn, Peter

2012-01-01

Brush seals have high potential for efficiency increase compared to conventional labyrinth seals in steam turbines. Due to less experience in operation today there is a lot of scepticism with customers of steam turbine manufacturers. Therefore this thesis is investigating characteristics of this type of seal. Experiments and numerical models will be presented, which lead to better knowledge about leakages and influence of flow through seal onto dynamics of rotor in comparison to labyrinth seals. This thesis is increasing area of experience and one more positive reference.

Gas-path leakage seal for a gas turbine

Science.gov (United States)

Wolfe, C.E.; Dinc, O.S.; Bagepalli, B.S.; Correia, V.H.; Aksit, M.F.

1996-04-23

A gas-path leakage seal is described for generally sealing a gas-path leakage-gap between spaced-apart first and second members of a gas turbine (such as combustor casing segments). The seal includes a generally imperforate foil-layer assemblage which is generally impervious to gas and is located in the leakage-gap. The seal also includes a cloth-layer assemblage generally enclosingly contacting the foil-layer assemblage. In one seal, the first edge of the foil-layer assemblage is left exposed, and the foil-layer assemblage resiliently contacts the first member near the first edge to reduce leakage in the ``plane`` of the cloth-layer assemblage under conditions which include differential thermal growth of the two members. In another seal, such leakage is reduced by having a first weld-bead which permeates the cloth-layer assemblage, is attached to the metal-foil-layer assemblage near the first edge, and unattachedly contacts the first member. 4 figs.

Dye filled security seal

International Nuclear Information System (INIS)

Wilson, D.C.

1982-01-01

A security seal for providing an indication of unauthorized access to a sealed object includes an elongate member to be entwined in the object such that access is denied unless the member is removed. The elongate member has a hollow, pressurizable chamber extending throughout its length that is filled with a permanent dye under greater than atmospheric pressure. Attempts to cut the member and weld it together are revealed when dye flows through a rupture in the chamber wall and stains the outside surface of the member

Fuel cell cassette with compliant seal

Science.gov (United States)

Karl, Haltiner, Jr. J.; Anthony, Derose J.; Klotzbach, Darasack C.; Schneider, Jonathan R.

2017-11-07

A fuel cell cassette for forming a fuel cell stack along a fuel cell axis includes a cell retainer, a plate positioned axially to the cell retainer and defining a space axially with the cell retainer, and a fuel cell having an anode layer and a cathode layer separated by an electrolyte layer. The outer perimeter of the fuel cell is positioned in the space between the plate and the cell retainer, thereby retaining the fuel cell and defining a cavity between the cell retainer, the fuel cell, and the plate. The fuel cell cassette also includes a seal disposed within the cavity for sealing the edge of the fuel cell. The seal is compliant at operational temperatures of the fuel cell, thereby allowing lateral expansion and contraction of the fuel cell within the cavity while maintaining sealing at the edge of the fuel cell.

SEALING LARGE-DIAMETER CAST-IRON PIPE JOINTS UNDER LIVE CONDITIONS

Energy Technology Data Exchange (ETDEWEB)

Kiran M. Kothari; Gerard T. Pittard

2005-07-01

Utilities in the U.S. operate over 75,000 km (47,000 miles) of old cast-iron pipes for gas distribution. Bell-and-spigot joints that connect pipe sections together tend to leak as these pipes age. Current repair practices are costly and highly disruptive. The objective of this program is to design, test and commercialize a robotic system capable of sealing multiple castiron bell and spigot joints from a single pipe entry point. The proposed system will perform repairs with the pipe in service by traveling through the pipe, cleaning each joint surface, and installing a stainless-steel sleeve lined with an epoxy-impregnated felt across the joint. This approach will save considerable time and labor, minimize excavation, avoid traffic disruption, and eliminate any requirement to interrupt service to customers (which would result in enormous expense to utilities). Technical challenges include: (1) repair sleeves must compensate for diametric variation and eccentricity of old cast-iron pipes; (2) the assembly must travel long distances through pipes containing debris; (3) the pipe wall must be effectively cleaned in the immediate area of the joint to assure good bonding of the sleeve; and (4) an innovative bolt-on entry fitting is required to conduct safe repair operations on live mains.

Failure of Magnetic Fluid Seals Operating in Water: Preliminary Conclusions

Directory of Open Access Journals (Sweden)

Matuszewski Leszek

2017-06-01

Full Text Available The article analyses properties of magnetic fluid seals installed in rotary sealing nodes which operate in the utility water environment. Seals of this type have been examined as a possible solution to the problem with ship manoeuvring propulsion sealing. The present analysis bases on laboratory durability tests of magnetic fluid seals exposed to longterm utility water loads, at different water pressures and shaft revolutions. The basic seal durability criterion was the number of revolutions made by the sealing node shaft until the appearance of water tightness loss (leakage. It was found that the main factor leading to the wear of the seal is the relative speed of the magnetic fluid with respect to that of the utility water, and this process is heavily affected by the pressure acting on the seal. The reported test results are presented in the form of diagrams showing the seal durability (time until water tightness loss as a function of rotational speed. The curves shown in the diagrams are regular, with two different rotational speed ranges: the highspeed range, when the tightness loss is relatively fast, and the low-speed range, with a clear tendency to prolong the seal lifetime. These diagrams were given the name of durability curves of the MF seal operating in water. The results of the performed tests suggest formal similarity between the experimental data distribution concerning tightness loss processes occurring in magnetic fluid seals operating in water environment and metal fatigue processes. The article proposes a preliminary simplified durability model to describe the examined phenomenon.

Movements and foraging areas of naove, recently weaned southern elephant seal pups

NARCIS (Netherlands)

McConnell, B.; Fedak, M.; Burton, H.R.; Engelhard, G.H.; Reijnders, P.J.H.

2002-01-01

1. Female southern elephant seals (Mirounga leonina L. ) expend variable, often large, amounts of their stored body resources on their pups during lactation. There is some evidence that pups with higher weaning masses have a better chance of survivingtheir first year. But in order to understand what

Electromagnetic shaft seal

International Nuclear Information System (INIS)

Takahashi, Kenji.

1994-01-01

As an electromagnetic shaft seal, there are disposed outwarding electromagnetic induction devices having generating power directing to an electroconductive fluid as an object of sealing, and inwarding electromagnetic induction device added coaxially. There are disposed elongate rectangular looped first coils having a predetermined inner diameter, second coils having the same shape and shifted by a predetermined pitch relative to the first coil and third coil having the same shape and shifted by a predetermined pitch relative to the second coil respectively each at a predetermined inner diameter of clearance to the outwarding electromagnetic induction devices and the inwarding electromagnetic induction device. If the inwarding electromagnetic induction device and the outwarding electromagnetic induction device are operated, they are stopped at a point that the generating power of the former is equal with the sum of the generating power of the latter and a differential pressure. When three-phase AC is charged to the first coil, the second coil and the third coil successively, a force is generated in the advancing direction of the magnetic field in the electroconductive fluid by the similar effect to that of a linear motor, and the seal is maintained at high reliability. Moreover, the limit for the rotational angle of the shaft is not caused. (N.H.)

Enclosed mechanical seal face design for brittle materials copyright

International Nuclear Information System (INIS)

Marsi, J.A.

1994-01-01

Metal carbides are widely used as seal face material due to their hardness and wear resistance. Silicon carbide (SiC) has excellent performance as a seal face material, but it is relatively brittle and may break due to accidental overloads outside the boundary of normal operating conditions. In mechanical seals for nuclear primary coolant pumps, the shattered SiC pieces can get into the reactor system and cause serious damage. The conventional method of containing an SiC seal face is to shrink-fit it in a holder, which may lead the seal designer to contend with unwanted seal face deflections. This paper presents a successful, tested design which does not rely on shrink-fits. 5 refs., 9 figs., 4 tabs

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

Science.gov (United States)

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.

Fluid moderator control system fuel assembly seal connector

International Nuclear Information System (INIS)

Veronesi, L.; Tower, S.N.; Klassen, W.E.

1987-01-01

A nuclear reactor is described comprising fuel assemblies having one or more flow channels therethrough, a core support plate having one or more flow channels therethrough, and seal connectors for sealingly connecting the one or more flow channels in the core support plate with the one or more flow channels in the fuel assemblies. The seal connectors each comprises a first portion and second portion each comprising an elongated member having a flow channel therethrough and being in substantial axial alignment with each other and being separated by a space therebetween, means for sealingly connecting the first portion o one or the one or more flow channels in the fuel assemblies, means for sealingly connecting the second portion to the first portion and for allowing relative motion between the portions, means for limiting the relative motion of the first and second portion in directions toward and away from each other, means for reconnectingly connecting and resealingly sealing the second portion to one of the one or more flow channels in the core support plate. It comprises a slip fit connection whereby the remote end of the second portion fits within whereby the remote end of the second portion fits within an opening in the core support plate which is in flow communication with the one or more flow channels in the core support plate and further comprises a ball and cones seal in series with axially spaced ring seals

A Study on Sealing Process of Anodized Al Alloy Film

Science.gov (United States)

Tsujita, Takeshi; Sato, Hiroshi; Tsukahara, Sonoko; Ishikawa, Yuuichi

Since sealing is an important process to improve the corrosion resistance in practical application of anodized aluminum, we prepared anodic oxide films on A5052 alloy in an oxalic acid bath and a sulfuric acid bath, sealed them at various conditions, and analyzed them by scanning electron microscopy, acid-dissolution examination, admittance measurements and infrared spectroscopy. The pore radius of the oxalic acid anodized film was about 5 times larger than that of sulfuric acid anodized film, while the corrosion resistance of the former showed about 2 times higher value than the latter with the same sealed state and amount of hydroxide formed by sealing process of the former was 6 times larger than the latter, respectively. Steam sealing formed dense hydroxide and boiling water sealing formed big coral-like hydroxide, whereas the corrosion resistance of the film sealed by the former showed about 1.5 times higher value than that sealed by the latter, respectively. Thus microstructure of anodic oxide films and their surface morphology after sealing process clearly depended on their anodizing solution and the sealing condition and showed obvious relation to electric and corrosive properties.

Global Wildfire Forecasts Using Large Scale Climate Indices

Science.gov (United States)

Shen, Huizhong; Tao, Shu

2016-04-01

Using weather readings, fire early warning can provided forecast 4-6 hour in advance to minimize fire loss. The benefit would be dramatically enhanced if relatively accurate long-term projection can be also provided. Here we present a novel method for predicting global fire season severity (FSS) at least three months in advance using multiple large-scale climate indices (CIs). The predictive ability is proven effective for various geographic locations and resolution. Globally, as well as in most continents, the El Niño Southern Oscillation (ENSO) is the dominant driving force controlling interannual FSS variability, whereas other CIs also play indispensable roles. We found that a moderate El Niño event is responsible for 465 (272-658 as interquartile range) Tg carbon release and an annual increase of 29,500 (24,500-34,800) deaths from inhalation exposure to air pollutants. Southeast Asia accounts for half of the deaths. Both intercorrelation and interaction of WPs and CIs are revealed, suggesting possible climate-induced modification of fire responses to weather conditions. Our models can benefit fire management in response to climate change.

Shaft seal assembly for high speed and high pressure applications

Science.gov (United States)

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.

Improvement in oil seal performance of gas compressor in HTTR

International Nuclear Information System (INIS)

Oyama, Sunao; Hamamoto, Shimpei; Nemoto, Takahiro; Sekita, Kenji; Isozaki, Minoru; Emori, Kouichi; Ohta, Yukimaru; Mizushima, Toshihiko; Kaneshiro, Noriyuki; Ito, Yoshiteru; Yamamoto, Hideo

2007-08-01

High-Temperature engineering Test Reactor (HTTR) built by Japan Atomic Energy Agency (JAEA) has reciprocating compressor commonly used to extract and discharge helium gas into primary/secondary coolant helium loop from helium purification system. Piston rod seal of the compressor consist of several components to prevent coolant leak. However, rod seal system has weak reliability during long term operation due to repeated leakage of seal oil in operation. As a result of investigations, leakage's root is found in that seal were used in a range beyond limit sliding properties of seal material. For this reason, a lip of the seal was worn and transformed itself and was not able to sustain a seal function. Therefore, through tests using facility actual equipment for endurance of candidate materials, one seal material were chosen for long term operation. (author)

Application of a magnetic fluid seal to rotary blood pumps

International Nuclear Information System (INIS)

Mitamura, Y; Arioka, S; Azegami, M; Sakota, D; Sekine, K

2008-01-01

A magnetic fluid seal enables mechanical contact-free rotation of a shaft without frictional heat and material wear and hence has excellent durability. However, the durability of a magnetic fluid seal decreases in liquid. The life of a seal applied to a rotary blood pump is not known. We have developed a magnetic fluid seal that has a shield mechanism minimizing the influence of the rotary pump on the magnetic fluid. The developed magnetic fluid seal worked for over 286 days in a continuous flow condition, for 24 days (on-going) in a pulsatile flow condition and for 24 h (electively terminated) in blood flow. The magnetic fluid seal is promising as a shaft seal for rotary blood pumps

VACOSS - variable coding seal system for nuclear material control

International Nuclear Information System (INIS)

Kennepohl, K.; Stein, G.

1977-12-01

VACOSS - Variable Coding Seal System - is intended to seal: rooms and containers with nuclear material, nuclear instrumentation and equipment of the operator, instrumentation and equipment at the supervisory authority. It is easy to handle, reusable, transportable and consists of three components: 1. Seal. The light guide in fibre optics with infrared light emitter and receiver serves as lead. The statistical treatment of coded data given in the seal via adapter box guarantees an extremely high degree of access reliability. It is possible to store the data of two undue seal openings together with data concerning time and duration of the opening. 2. The adapter box can be used for input or input and output of data indicating the seal integrity. 3. The simulation programme is located in the computing center of the supervisory authority and permits to determine date and time of opening by decoding the seal memory data. (orig./WB) [de

Test of Seal System for Flexible Pipe End Fitting

DEFF Research Database (Denmark)

Banke, Lars; Jensen, Thomas Gregers

1999-01-01

The purpose of the end fitting seal system is to ensure leak proof termination of flexible pipes. The seal system of an NKT end fitting normally consists of a number of ring joint gaskets mounted in a steel sleeve on the outside of the polymeric inner liner of the pipe. The seal system is activated...... by compression of the gaskets, thus using the geometry to establish a seal towards the inner liner of the pipe and the steel sleeve of the end fitting. This paper describes how the seal system of an end fitting can be tested using an autoclave. By regulating temperature and pressure, the seal system can...... be tested up to 130oC and 51.7 MPa. Pressure, temperature and the mechanical behaviours of the pipe are measured for use in further research. The set-up is used to test the efficiency of the seal system as function of parameters such as cross sectional shapes of the gaskets, tolerances between gaskets...

Stirling engine or heat pump having an improved seal

Science.gov (United States)

White, Maurice A.; Riggle, Peter; Emigh, Stuart G.

1985-01-01

A Stirling Engine or Heat Pump having two relatively movable machine elements for power transmission purposes includes a hermetic seal bellows interposed between the elements for separating a working gas from a pressure compensating liquid that balances pressure across the bellows to reduce bellows stress and to assure long bellows life. The volume of pressure compensating liquid displaced due to relative movement between the machine elements is minimized by enclosing the compensating liquid within a region exposed to portions of both machine elements at one axial end of a slidable interface presented between them by a clearance seal having an effective diameter of the seal bellows. Pressure equalization across the bellows is achieved by a separate hermetically sealed compensator including a movable enclosed bellows. The interior of the compensator bellows is in communication with one side of the seal bellows, and its exterior is in communication with the remaining side of the seal bellows. A buffer gas or additional liquid region can be provided at the remaining axial end of the clearnace seal, along with valved arrangements for makeup of liquid leakage through the clearance seal.

Soil Monitor: an advanced and freely accesible platform to challenge soil sealing in Italy

Science.gov (United States)

Langella, Giuliano; Basile, Angelo; Giannecchini, Simone; Domenico Moccia, Francesco; Munafò, Michele; Terribile, Fabio

2017-04-01

Soil sealing is known to be one of the most serious soil degradation processes since it greatly disturbs or removes essential ecosystem services. Although important policy documents (Roadmap to a Resource Efficient in Europe, SDG'S) promise to mitigate this problem, there are still no signs of change and today soil sealing continues to increase globally. We believe an immediate action is required to reduce the distance between the grand policy declarations and the poor availability of operational - and scientifically robust - tools to challenge soil sealing. These tools must be able to support the decisions made by people who manage and control the soil sealing, namely urban and landscape planning professionals and authorities. In this contribution, we demonstrate that soil sealing can be effectively challenged by the implementation of a dedicated Geospatial Cyberinfrastructure. The platform we are developing - named Soil Monitor - is at now a well-functioning prototype freely available at http://www.soilmonitor.it/. It has been developed by research scientists coming from different disciplines. The national authority for environmental protection (ISPRA) provided the dataset while INU (Italian association of urban planners) tested the soil sealing and the urban planning indicators. More generally, Soil Monitor has been designed to support the Italian policy documents connected to soil sealing: AS 1181, AS 2383, L. 22 May 2015, n. 68; L. 28 December, n. 221). Thus, it connects many different soil sealing aspects including science, community, policy and economy. Soil Monitor performs geospatial computation in real-time to support the decision making in the landscape planning. This aims at measuring soil sealing in order to mitigate it and in particular at recognizing actions to achieve the land degradation neutrality. The web platform covers the entire Italy, even though it is "Country-agnostic". Data are processed at a very high spatial resolution (10-20 m), which

Performance assessment of sealing systems. Conceptual and integrated modelling of plugs and seals

Energy Technology Data Exchange (ETDEWEB)

Ruebel, Andre; Buhmann, Dieter; Kindlein, Jonathan; Lauke, Thomas

2016-08-15

The long-time isolation of radionuclides from the biosphere is the goal of the storage of radioactive waste in deep geological repositories. For repositories in rock salt, this goal is achieved on the one hand by the impermeable undisturbed part of the salt host rock formation and on the other hand by crushed salt, which is used to backfill the mine openings in the emplacement areas and galleries created during the construction of the repository. The crushed salt backfill is compacted over time and achieves a sufficiently high hydraulic resistance to avoid inflow of brines into the emplacement areas of the repository in the long-term. Plugs and seals must additionally provide their sealing function during the early post closure phase, until the compaction of the backfill is adequate and the permeability of the backfill is sufficiently low. To assess the future development of the waste repository, an adequate knowledge of the material behaviour is necessary and related mathematical models must be developed to be able to perform predictions on the long-term safety of the repository. An integrated performance assessment model was formulated that describes the long-term behaviour of a sealing built from salt concrete. The average permeability of the sealing changes with time after its emplacement from various processes of which two were regarded in a constitutive model: first, the healing of the EDZ in the host rock around the sealing, and second, the corrosion of the salt concrete material resulting from brine attack. Empirical parameter model functions were defined for both processes to reflect the actual behaviour. The mathematical model was implemented in the integrated performance assessment model LOPOS which is used by GRS as near-field model for repositories in salt. Deterministic and probabilistic calculations were performed with realistic parameters showing how the permeability of the sealing decreases during the first 2 000 years due to the healing of the EDZ

Performance assessment of sealing systems. Conceptual and integrated modelling of plugs and seals

International Nuclear Information System (INIS)

Ruebel, Andre; Buhmann, Dieter; Kindlein, Jonathan; Lauke, Thomas

2016-08-01

The long-time isolation of radionuclides from the biosphere is the goal of the storage of radioactive waste in deep geological repositories. For repositories in rock salt, this goal is achieved on the one hand by the impermeable undisturbed part of the salt host rock formation and on the other hand by crushed salt, which is used to backfill the mine openings in the emplacement areas and galleries created during the construction of the repository. The crushed salt backfill is compacted over time and achieves a sufficiently high hydraulic resistance to avoid inflow of brines into the emplacement areas of the repository in the long-term. Plugs and seals must additionally provide their sealing function during the early post closure phase, until the compaction of the backfill is adequate and the permeability of the backfill is sufficiently low. To assess the future development of the waste repository, an adequate knowledge of the material behaviour is necessary and related mathematical models must be developed to be able to perform predictions on the long-term safety of the repository. An integrated performance assessment model was formulated that describes the long-term behaviour of a sealing built from salt concrete. The average permeability of the sealing changes with time after its emplacement from various processes of which two were regarded in a constitutive model: first, the healing of the EDZ in the host rock around the sealing, and second, the corrosion of the salt concrete material resulting from brine attack. Empirical parameter model functions were defined for both processes to reflect the actual behaviour. The mathematical model was implemented in the integrated performance assessment model LOPOS which is used by GRS as near-field model for repositories in salt. Deterministic and probabilistic calculations were performed with realistic parameters showing how the permeability of the sealing decreases during the first 2 000 years due to the healing of the EDZ

SEALING LARGE-DIAMETER CAST-IRON PIPE JOINTS UNDER LIVE CONDITIONS

Energy Technology Data Exchange (ETDEWEB)

Kiran M. Kothari; Gerard T. Pittard

2003-06-01

Utilities in the U.S. operate over 75,000 km (47,000 miles) of old cast-iron pipes for gas distribution. The bell-and-spigot joints tend to leak as these pipes age. Current repair practices are costly and highly disruptive. The objective of this program is to design, test and commercialize a robotic system capable of sealing multiple cast-iron bell and spigot joints from a single pipe entry point. The proposed system will perform repairs while the pipe remains in service by traveling through the pipe, cleaning each joint surface, and attaching a stainless-steel sleeve lined with an epoxy-impregnated felt across the joint. This approach will save considerable time and labor, avoid traffic disruption, and eliminate any requirement to interrupt service (which results in enormous expense to utilities). Technical challenges include: (1) repair sleeves must compensate for diametric variation and eccentricity of cast-iron pipes; (2) the assembly must travel long distances through pipes containing debris; (3) the pipe wall must be effectively cleaned in the immediate area of the joint to assure good bonding of the sleeve; and (4) an innovative bolt-on entry fitting is required to conduct repair operations on live mains. The development effort is divided into eleven tasks. Task 1-Program Management was previously completed. Two reports, one describing the program management plan and the other consisting of the technology assessment, were submitted to the DOE COR in the first quarter. Task 2-Establishment of Detailed Design Specifications and Task 3-Design and Fabricate Ratcheting Stainless-Steel Repair Sleeves are now well underway. First-quarter activities included conducting detailed analyses to determine the capabilities of coiled-tubing locomotion for entering and repairing gas mains and the first design iteration of the joint-sealing sleeve. The maximum horizontal reach of coiled tubing inside a pipeline before buckling prevents further access was calculated for a wide

Materials for water pump mechanical seals

International Nuclear Information System (INIS)

Brousse, P.

1992-01-01

In view of the continually increasing power ratings of conventional and nuclear power plants and the related reliability and safety problems, plant builders have had to develop seal systems compatible with current water pump performances. In 1970, EDF/R and DD was already concerned by this problem. It soon became obvious that the nature of the materials used for the friction surfaces was decisive for seal durability. Exceptional loads (transients, high vibration levels, etc...) hasten aging. To begin with, friction surfaces consisted of a hard material (tungsten carbide) mated with a soft material (carbon). Resistance was unpredictable and not compatible with industrial requirements. Tests performed on the EDF/R and DD test benches evidenced the same types of degradation. The mechanical seal manufacturers then began to use ceramic materials (silicon carbide), which raised high expectations. Unfortunately, these were recent materials and their manufacturing process was not thoroughly understood. Hopes were soon dashed in many applications, including that of mechanical seals. Fluctuating results were obtained over the next few years. The raw material suppliers made progress, especially with regard to reducing fragility. On a parallel, the mechanical seal manufacturers initiated comparative tests on the friction resistance of materials. It has also been established that ceramics have to be stringently supervised at all levels: part design, inspection, assembly, use. EDF has much insisted that mechanical seal suppliers guarantee the constant quality of their products. EDF/R and DD has systematically tested new sensitive devices, under normal and exceptional conditions, prior to their installation at the plants. At the present time, the silicon carbides proposed by the mechanical seal suppliers are entirely satisfactory. The carbon mating surface was far less problematic. The required reliability was obtained by replacing resin binder carbons by the more resistant

The CANDU irradiated fuel safeguards sealing system at the threshold of implementation

International Nuclear Information System (INIS)

Stirling, A.J.; Kupca, S.; Martin, R.E.; West, R.J.; Aikens, A.E.; Cox, C.A.; White, B.F.; Smith, M.T.; Payne, W.E.

1985-07-01

The development of a safeguards containment and surveillance system for the irradiated fuel discharged from CANDU nuclear generating stations has inspired the development of three different sealing technologies. Each seal type utilizes a random seal identity of different design. The AECL Random Coil (ARC) Seal combines the identity and integrity elements in the ultrasonic signature of a wire coil. Two variants of an optical seal have been developed which features identity elements of crystalline zirconium and aluminum. The sealed cap-seal uses a conventional IAEA 'Type X Seal' (wire seal). The essential features and relative merits of each seal design are described

Temporary fire sealing of penetrations on TFTR

International Nuclear Information System (INIS)

Hondorp, H.L.

1981-02-01

The radiation shielding provided for TFTR for D-D and D-T operation will be penetrated by numerous electrical and mechanical services. Eventually, these penetrations will have to be sealed to provide the required fire resistance, tritium sealability, pressure integrity and radiation attenuation. For the initial hydrogen operation, however, fire sealing of the penetrations in the walls and floor is the primary concern. This report provides a discussion of the required and desirable properties of a temporary seal which can be used to seal these penetrations for the hydrogen operation and then subsequently be removed and replaced as required for the D-D and D-T operations. Several candidate designs are discussed and evaluated and recommendations are made for specific applications

Wafer-level packaging with compression-controlled seal ring bonding

Science.gov (United States)

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.

O-Ring sealing arrangements for ultra-high vacuum systems

Science.gov (United States)

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.

76 FR 2930 - International Product Change-Global Expedited Package Services-Non- Published Rates

Science.gov (United States)

2011-01-18

... POSTAL SERVICE International Product Change--Global Expedited Package Services-- Non- Published... request with the Postal Regulatory Commission to add Global Expedited Package Services-- Non-Published...--Non-Published Rates, to the Competitive Products List, and Notice of Filing (Under Seal) the Enabling...

Cluster-based Reduced-order Modelling of Flow in the Wake of a Seal-vibrissa-shaped Cylinder

Science.gov (United States)

Wei, Zheng; Li, Qiliang; Yang, Zhigang; Xia, Chao; Shanghai Automotive Wind Tunnel Center Team

2017-11-01

The flow around a seal-vibrissa-shaped cylinder is numerically calculated using large eddy simulation (LES) at the Reynolds number of 20000, along with a smooth and a twisted cylinder for comparison. The mean drag coefficient of the seal-vibrissa-shaped cylinder is lower than that of the smooth and twisted cylinders, respectively. The fluctuating lift coefficient of the seal-vibrissa-shaped cylinder shows a substantial decrease compared with the smooth cylinder. The seal-vibrissa-shaped surface leads to more stable wake, longer vortex formation length, higher base pressure and three-dimensional separation. In addition, cluster-based reduced-order modelling (CROM) is performed to analyze phase-dependent variations of the wake flow, which discloses the complex unsteady behavior in different cross sections. Meanwhile, two flow regimes, anti-phased and in-phase-dominated vortex shedding, generated by the twisted cylinder and the seal-vibrissa-shaped cylinder are distinguished and extracted, their interrelationship are evaluated, and the question how forces are affected is answered. Supported by the National Key Research and Development Program of China (2016YFB1200503-04) and the Shanghai Automotive Wind Tunnel Technical Service Platform (16DZ2290400).

Bentonite as a waste isolation pilot plant shaft sealing material

International Nuclear Information System (INIS)

Daemen, J.; Ran, Chongwei

1996-12-01

Current designs of the shaft sealing system for the Waste Isolation Pilot Plant (WIPP) propose using bentonite as a primary sealing component. The shaft sealing designs anticipate that compacted bentonite sealing components can perform through the 10,000-year regulatory period and beyond. To evaluate the acceptability of bentonite as a sealing material for the WIPP, this report identifies references that deal with the properties and characteristics of bentonite that may affect its behavior in the WIPP environment. This report reviews published studies that discuss using bentonite as sealing material for nuclear waste disposal, environmental restoration, toxic and chemical waste disposal, landfill liners, and applications in the petroleum industry. This report identifies the physical and chemical properties, stability and seal construction technologies of bentonite seals in shafts, especially in a saline brine environment. This report focuses on permeability, swelling pressure, strength, stiffness, longevity, and densification properties of bentonites

Bentonite as a waste isolation pilot plant shaft sealing material

Energy Technology Data Exchange (ETDEWEB)

Daemen, J.; Ran, Chongwei [Univ. of Nevada, Reno, NV (United States)

1996-12-01

Current designs of the shaft sealing system for the Waste Isolation Pilot Plant (WIPP) propose using bentonite as a primary sealing component. The shaft sealing designs anticipate that compacted bentonite sealing components can perform through the 10,000-year regulatory period and beyond. To evaluate the acceptability of bentonite as a sealing material for the WIPP, this report identifies references that deal with the properties and characteristics of bentonite that may affect its behavior in the WIPP environment. This report reviews published studies that discuss using bentonite as sealing material for nuclear waste disposal, environmental restoration, toxic and chemical waste disposal, landfill liners, and applications in the petroleum industry. This report identifies the physical and chemical properties, stability and seal construction technologies of bentonite seals in shafts, especially in a saline brine environment. This report focuses on permeability, swelling pressure, strength, stiffness, longevity, and densification properties of bentonites.

Magnetic nanofluids and magnetic composite fluids in rotating seal systems

International Nuclear Information System (INIS)

Borbath, T; Borbath, I; Boros, T; Bica, D; Vekas, L; Potencz, I

2010-01-01

Recent results are presented concerning the development of magnetofluidic leakage-free rotating seals for vacuum and high pressure gases, evidencing significant advantages compared to mechanical seals. The micro-pilot scale production of various types of magnetizable sealing fluids is shortly reviewed, in particular the main steps of the chemical synthesis of magnetic nanofluids and magnetic composite fluids with light hydrocarbon, mineral oil and synthetic oil carrier liquids. The behavior of different types of magnetizable fluids in the rotating sealing systems is analyzed. Design concepts, some constructive details and testing procedures of magnetofluidic rotating seals are presented such as the testing equipment. The main characteristics of several magnetofluidic sealing systems and their applications will be presented: vacuum deposition systems and liquefied gas pumps applications, mechanical and magnetic nanofluid combined seals, gas valves up to 40 bar equipped by rotating seal with magnetic nanofluids and magnetic composite fluids.

Sensitivity analysis overlaps of friction elements in cartridge seals

Directory of Open Access Journals (Sweden)

Žmindák Milan

2018-01-01

Full Text Available Cartridge seals are self-contained units consisting of a shaft sleeve, seals, and gland plate. The applications of mechanical seals are numerous. The most common example of application is in bearing production for automobile industry. This paper deals with the sensitivity analysis of overlaps friction elements in cartridge seal and their influence on the friction torque sealing and compressive force. Furthermore, it describes materials for the manufacture of sealings, approaches usually used to solution of hyperelastic materials by FEM and short introduction into the topic wheel bearings. The practical part contains one of the approach for measurement friction torque, which results were used to specifying the methodology and precision of FEM calculation realized by software ANSYS WORKBENCH. This part also contains the sensitivity analysis of overlaps friction elements.

Comment on 'Quantum string seal is insecure'

International Nuclear Information System (INIS)

He Guangping

2007-01-01

An attack strategy was recently proposed by Chau [Phys. Rev. A 75, 012327 (2007)], which was claimed to be able to break all quantum string seal protocols. Here it will be shown that the attack cannot obtain nontrivial information and escape the detection simultaneously in a class of quantum string seal, including the one proposed by He [Int. J. Quantum Inf. 4, 677 (2006)]. Thus it is insufficient to conclude that all quantum string seals are insecure

A seal analyzer for testing container integrity

International Nuclear Information System (INIS)

McDaniel, P.; Jenkins, C.

1988-01-01

This paper reports on the development of laboratory and production seal analyzer that offers a rapid, nondestructive method of assuring the seal integrity of virtually any type of single or double sealed container. The system can test a broad range of metal cans, drums and trays, membrane-lidded vessels, flexible pouches, aerosol containers, and glass or metal containers with twist-top lids that are used in the chemical/pesticide (hazardous materials/waste), beverage, food, medical and pharmaceutical industries

HMSRP Hawaiian Monk Seal Telemetry Tag Deployments

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This project investigates foraging behavior of Hawaiian monk seals by conducting telemetry studies. During these studies, live seals are instrumented with dive...

HMSRP Hawaiian Monk Seal Argos Location Data

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This project investigates foraging behavior of Hawaiian monk seals by conducting telemetry studies. During these studies, live seals are instrumented with satellite...

EXPERIMENTAL STUDY OF MAGNETIC FLUID SEAL

Directory of Open Access Journals (Sweden)

V. G. Bashtovoi

2006-01-01

Full Text Available Dependences of critical pressure drop, being held by magnetic fluid seal, on time in a static state and shaft rotation velocity in dynamics have been experimentally determined. The significant influence of particles’ redistribution in magnetic fluid on static parameters of magnetic fluid seal has been established.

SEALING LARGE-DIAMETER CAST-IRON PIPE JOINTS UNDER LIVE CONDITIONS

Energy Technology Data Exchange (ETDEWEB)

Kiran M. Kothari, Gerard T. Pittard

2004-01-01

Utilities in the U.S. operate over 75,000 km (47,000 miles) of old cast-iron pipes for gas distribution. The bell-and-spigot joints that connect pipe sections together tend to leak as these pipes age. Current repair practices are costly and highly disruptive. The objective of this program is to design, test and commercialize a robotic system capable of sealing multiple cast iron bell and spigot joints from a single pipe entry point. The proposed system will perform repairs while the pipe remains in service by traveling through the pipe, cleaning each joint surface, and installing a stainless-steel sleeve lined with an epoxy-impregnated felt across the joint. This approach will save considerable time and labor, avoid traffic disruption, and eliminate any requirement to interrupt service to customers (which would result in enormous expense to utilities). Technical challenges include: (1) repair sleeves must compensate for diametric variation and eccentricity of cast-iron pipes; (2) the assembly must travel long distances through pipes containing debris; (3) the pipe wall must be effectively cleaned in the immediate area of the joint to assure good bonding of the sleeve; and (4) an innovative bolt-on entry fitting is required to conduct repair operations on live mains. The development effort is divided into eleven tasks. Task 1--Program Management and Task 2--were completed in prior quarters while Task 3--Design and Fabricate Ratcheting Stainless-Steel Repair Sleeves has progressed to installing prototype sleeves in cast iron test pipe segments. Efforts in this quarter continued to focus on Tasks 4--8, with significant progress made in each. Task 4 (Design, Fabricate and Test Patch Setting Robotic Train) progressed to the design of the control electronics and pneumatic system to inflate the bladder robotic patch setting module. Task 5 (Design & Fabricate Pipe-Wall Cleaning Robot Train with Pan/Zoom/Tilt Camera) continued with additional in-pipe testing required to

SEALING LARGE-DIAMETER CAST-IRON PIPE JOINTS UNDER LIVE CONDITIONS

Energy Technology Data Exchange (ETDEWEB)

Kiran M Kothari; Gerard T. Pittard

2004-07-01

Utilities in the U.S. operate over 75,000 km (47,000 miles) of old cast-iron pipes for gas distribution. The bell-and-spigot joints that connect pipe sections together tend to leak as these pipes age. Current repair practices are costly and highly disruptive. The objective of this program is to design, test and commercialize a robotic system capable of sealing multiple castiron bell and spigot joints from a single pipe entry point. The proposed system will perform repairs while the pipe remains in service by traveling through the pipe, cleaning each joint surface, and installing a stainless-steel sleeve lined with an epoxy-impregnated felt across the joint. This approach will save considerable time and labor, avoid traffic disruption, and eliminate any requirement to interrupt service to customers (which would result in enormous expense to utilities). Technical challenges include: (1) repair sleeves must compensate for diametric variation and eccentricity of cast-iron pipes; (2) the assembly must travel long distances through pipes containing debris; (3) the pipe wall must be effectively cleaned in the immediate area of the joint to assure good bonding of the sleeve; and (4) an innovative bolt-on entry fitting is required to conduct repair operations on live mains. The development effort is divided into eleven tasks. Task 1 (Program Management) and Task 2 (Establishment of Detailed Design Specifications) were completed in prior quarters while Task 3 (Design and Fabricate Ratcheting Stainless-Steel Repair Sleeves) has progressed to installing prototype sleeves in cast iron test pipe segments. Efforts in this quarter continued to focus on Tasks 4-8, with significant progress made in each. Task 4 (Design, Fabricate and Test Patch Setting Robotic Train) progressed to the design of the control electronics and pneumatic system to inflate the bladder robotic patch setting module. Task 5 (Design & Fabricate Pipe-Wall Cleaning Robot Train with Pan/Zoom/Tilt Camera

SEALING LARGE-DIAMETER CAST-IRON PIPE JOINTS UNDER LIVE CONDITIONS

Energy Technology Data Exchange (ETDEWEB)

Kiran M. Kothari; Gerard T. Pittard

2004-04-01

Utilities in the U.S. operate over 75,000 km (47,000 miles) of old cast-iron pipes for gas distribution. The bell-and-spigot joints that connect pipe sections together tend to leak as these pipes age. Current repair practices are costly and highly disruptive. The objective of this program is to design, test and commercialize a robotic system capable of sealing multiple cast-iron bell and spigot joints from a single pipe entry point. The proposed system will perform repairs while the pipe remains in service by traveling through the pipe, cleaning each joint surface, and installing a stainless-steel sleeve lined with an epoxy-impregnated felt across the joint. This approach will save considerable time and labor, avoid traffic disruption, and eliminate any requirement to interrupt service to customers (which would result in enormous expense to utilities). Technical challenges include: (1) repair sleeves must compensate for diametric variation and eccentricity of cast-iron pipes; (2) the assembly must travel long distances through pipes containing debris; (3) the pipe wall must be effectively cleaned in the immediate area of the joint to assure good bonding of the sleeve; and (4) an innovative bolt-on entry fitting is required to conduct repair operations on live mains. The development effort is divided into eleven tasks. Task 1--Program Management and Task 2--were completed in prior quarters while Task 3--Design and Fabricate Ratcheting Stainless-Steel Repair Sleeves has progressed to installing prototype sleeves in cast iron test pipe segments. Efforts in this quarter continued to focus on Tasks 4--8, with significant progress made in each. Task 4 (Design, Fabricate and Test Patch Setting Robotic Train) progressed to the design of the control electronics and pneumatic system to inflate the bladder robotic patch setting module. Task 5 (Design & Fabricate Pipe-Wall Cleaning Robot Train with Pan/Zoom/Tilt Camera) continued with additional in-pipe testing required to

Movements and foraging areas of naive, recently weaned southern elephant seal pups

NARCIS (Netherlands)

McConnell, B; Fedak, M; Burton, HR; Engelhard, GH; Reijnders, PJH

1. Female southern elephant seals (Mirounga leonina L.) expend variable, often large, amounts of their stored body resources on their pups during lactation. There is some evidence that pups with higher weaning masses have a better chance of surviving their first year. But in order to understand what

Straight cylindrical seal for high-performance turbomachines

Science.gov (United States)

Hendricks, Robert C.

1987-01-01

A straight cylindrical seal configuration representing the seal for a high-performance turbopump (e.g., the space shuttle main engine fuel pump) was tested under static (nonrotating) conditions. The test data included critical mass flux and pressure profiles over a wide range of inlet temperatures and pressures for fluid nitrogen and fluid hydrogen with the seal in concentric and fully eccentric positions. The critical mass fluxes (or leakage rates) for the concentric and fully eccentric configurations were nearly the same when based on stagnation conditions upstream of the seal. The fully eccentric configuration pressure profiles of the gas and liquid were different. Further, the pressure differences between the maximum and the minimum clearance positions were highly dependent on the geometric conditions, the temperature, and the absolute pressure at both the inlet and the exit. The pressure differences were greatest in the inlet region. The results, although complex, tend to follow the corresponding-states principles for critical flows. Gaseous injection near the seal exit plane significantly altered the pressure profiles and could be used to control turbomachine instabilities.

MWTF jumper connector integral seal block development and leak testing

International Nuclear Information System (INIS)

Ruff, E.S.; Jordan, S.R.

1995-01-01

In fiscal year 1993, tests of an o-ring/tetraseal retainer designed to replace a gasket-type seal used in PUREX-type process jumper connectors encouraged the design of an improved seal block. This new seal block combines several parts into one unitized component called an integral seal block. This report summarizes development and leak testing of the new integral seal block. The integral seal block uses a standard o-ring nested in a groove to accomplish leak tightness. This seal block eliminates the need to machine acme threads into the lower skirt casting and seal retainers, eliminates tolerance stack-up, reduces parts inventory, and eliminates an unnecessary leak path in the jumper connector assembly. This report also includes test data on various types of o-ring materials subjected to heat and pressure. Materials tested included Viton, Kalrez, and fluorosilicone, with some incidental data on teflon coated silicone o-rings. Test experience clearly demonstrates the need to test each seal material for temperature and pressure in its intended application. Some materials advertised as being open-quotes betterclose quotes at higher temperatures did not perform up to expectations. Inspection of the fluorosilicone and Kalrez seals after thermal testing indicates that they are much more susceptible to heat softening than Viton

WIPP [Waste Isolation Pilot Plant] panel entryway seal: Numerical simulation of seal composite interaction for preliminary design evaluation

International Nuclear Information System (INIS)

Argueello, J.G.

1988-04-01

This report presents the results of a series of structural analyses performed to evaluate the structural interaction of the components of a potential two-component panel entryway seal configuration with each other and with the rock salt formation at the repository horizon of the Waste Isolation Pilot Plant. A two-dimensional axisymmetric geomechanical model is used to numerically simulate the interaction of the components of a 30.48 m (100 ft) long seal, consisting of concrete end caps and a crushed salt core, with each other and with the surrounding formation. Issues addressed in this report pertain to the consolidation of the crushed salt in terms of how much of the seal core reaches effective consolidation in the presence of the stiff concrete end caps since these could conceivably cause bridging (retardation of closure around the core) to occur. In addition, the stress field in the end caps is evaluated to determine if the concrete component maintains its integrity. The stresses induced in the surrounding formation are also evaluated to determine if the presence of the concrete component in the seal system results in a ''tightening'' of the formation around the seal. 20 refs., 43 figs., 2 tabs

Compliant Glass Seals for SOFC Stacks

Energy Technology Data Exchange (ETDEWEB)

Chou, Yeong -Shyung [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Choi, Jung-Pyung [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Xu, Wei [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Stephens, Elizabeth V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Koeppel, Brian J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Stevenson, Jeffry W. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lara-Curzio, Edgar [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2014-04-30

This report summarizes results from experimental and modeling studies performed by participants in the Solid-State Energy Conversion Alliance (SECA) Core Technology Program, which indicate that compliant glass-based seals offer a number of potential advantages over conventional seals based on de-vitrifying glasses, including reduced stresses during stack operation and thermal cycling, and the ability to heal micro-damage induced during thermal cycling. The properties and composition of glasses developed and/or investigated in these studies are reported, along with results from long-term (up to 5,800h) evaluations of seals based on a compliant glass containing ceramic particles or ceramic fibers.

19 CFR 101.7 - Customs seal.

Science.gov (United States)

2010-04-01

... 19 Customs Duties 1 2010-04-01 2010-04-01 false Customs seal. 101.7 Section 101.7 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY GENERAL PROVISIONS § 101.7 Customs seal. (a) Design. According to the design furnished by the Department...

Pre-partum diet of adult female bearded seals in years of contrasting ice conditions.

Directory of Open Access Journals (Sweden)

Mark A Hindell

Full Text Available Changing patterns of sea-ice distribution and extent have measurable effects on polar marine systems. Beyond the obvious impacts of key-habitat loss, it is unclear how such changes will influence ice-associated marine mammals in part because of the logistical difficulties of studying foraging behaviour or other aspects of the ecology of large, mobile animals at sea during the polar winter. This study investigated the diet of pregnant bearded seals (Erignathus barbatus during three spring breeding periods (2005, 2006 and 2007 with markedly contrasting ice conditions in Svalbard using stable isotopes (δ(13C and δ(15N measured in whiskers collected from their newborn pups. The δ(15N values in the whiskers of individual seals ranged from 11.95 to 17.45 ‰, spanning almost 2 full trophic levels. Some seals were clearly dietary specialists, despite the species being characterised overall as a generalist predator. This may buffer bearded seal populations from the changes in prey distributions lower in the marine food web which seems to accompany continued changes in temperature and ice cover. Comparisons with isotopic signatures of known prey, suggested that benthic gastropods and decapods were the most common prey. Bayesian isotopic mixing models indicated that diet varied considerably among years. In the year with most fast-ice (2005, the seals had the greatest proportion of pelagic fish and lowest benthic invertebrate content, and during the year with the least ice (2006, the seals ate more benthic invertebrates and less pelagic fish. This suggests that the seals fed further offshore in years with greater ice cover, but moved in to the fjords when ice-cover was minimal, giving them access to different types of prey. Long-term trends of sea ice decline, earlier ice melt, and increased water temperatures in the Arctic are likely to have ecosystem-wide effects, including impacts on the forage bases of pagophilic seals.

Evaluation of RF seals for resonant cavity applications

International Nuclear Information System (INIS)

Rusnak, B.; Spalek, G.; Bolme, G.O.; Bultman, N.; Klapetkzy, A.; Kemp, E.L.; Stovall, J.E.; Rose, J.

1991-01-01

In radio-frequency quadrupoles (RFQ) and drift-tube linacs (DTL), electrical seals are required at mechanical interfaces to preserve the cavity quality factor (Q). Studies determined the response of copper-plated C-seals to continuous wave (cw), highfield operating conditions. In addition, low-power evaluations of machined-surface, knife-edge, indium wire, C-type, and multilam seals were done at room temperature and cryogenic (25 K) temperatures. For the high-field tests, the Q as well as seal temperature, was measured with power. For the low power test, the Q was measured as a function of temperature

Improved circumferential shaft seal for aircraft gear transmissions

Science.gov (United States)

Ludwig, L. P.; Strom, T. N.

1973-01-01

Operation under simulated aircraft transmission conditions of speeds to 2850 m/min (9350 ft/min), lubricant temperatures to 394 K (250 F), shaft radial runouts to 0.254 mm (0.010 in.) F.I.R. (full indicator reading), and pressure differentials to 1.03 N/cm2 (1.5 psi) revealed that conventional circumferential seals leaked excessively. Modifying the conventional seal by adding helical grooves to the seal bore reduced leakage rates to within the acceptable level of 10 cm3/hr. The leakage rate of this modified seal was not significantly affected by lubricant flooding or by shaft radial runout.

A coupled mechanical/hydrologic model for WIPP shaft seals

International Nuclear Information System (INIS)

Ehgartner, B.

1991-06-01

Effective sealing of the Waste Isolation Pilot Plant (WIPP) shafts will be required to isolate defense-generated transuranic wastes from the accessible environment. Shafts penetrate water-bearing hard rock formations before entering a massive creeping-salt formation (Salado) where the WIPP is located. Short and long-term seals are planned for the shafts. Short-term seals, a composite of concrete and bentonite, will primarily be located in the hard rock formations separating the water-bearing zones from the Salado Formation. These seals will limit water flow to the underlying long-term seals in the Salado. The long-term seals will consist of lengthly segments of initially unsaturated crushed salt. Creep closure of the shaft will consolidate unsaturated crushed salt, thereby reducing its permeability. However, water passing through the upper short-term seals and brine inherent to the salt host rock itself will eventually saturate the crushed salt and consolidation could be inhibited. Before saturating, portions of the crushed salt in the shafts are expected to consolidate to a permeability equivalent to the salt host rock, thereby effectively isolating the waste from the overlying water-bearing formations. A phenomenological model is developed for the coupled mechanical/hydrologic behavior of sealed WIPP shafts. The model couples creep closure of the shaft, crushed salt consolidation, and the associated reduction in permeability with Darcy's law for saturated fluid flow to predict the overall permeability of the shaft seal system with time. 17 refs., 6 figs., 1 tab

α-sealed transfer device and portable plastic film sealers

International Nuclear Information System (INIS)

Fu Zhujun; Shan Ruixia

1990-04-01

An α transfer device which can be operated remotely is presented. The device is able to perform sealed transfer of radioactive articles from a hot cell or shielded glove box to the outside and non-radioactive articles from the outside to a hot cell or shielded glove box by using bag sealing technology. The structure of the transfer device is simple. Its operation is safe and reliable. The sealing performance of the device is very good (for alpha). The use of this transfer device will greatly reduce α contamination of the building and creates a favourable condition for operating radioactive materials in an undivided area. The portable heat sealing device is also a necessary tool in bag sealing technology and α-sealed transfer. Two types of portable plastic film sealers have been developed. Their structure is simple. The operation of the portable plastic film sealers is easy. Their performance is also excellent. Both the α-sealed transfer device and portable plastic film sealers are very useful to the reprocessing plant of nuclear fuel

UPTF loop seal tests and their RELAP simulation

International Nuclear Information System (INIS)

Tuomainen, M.; Tuunanen, J.

1997-01-01

In a pressurized water reactor the loop seals have an effect on the natural circulation. If a loop seal is filled with water it can cause a flow stagnation in the loop during two-phase natural circulation. Also the pressure loss over a filled loop seal is high, which lowers the water level in the core. Tests to investigate the loop seal behaviour were performed on a German Upper Plenum Test Facility (UPTF). The purpose of the tests was to study the amount of water in the loop seal under different steam flow rates. The tests were simulated with RELAP5/MOD3.2. With high steam flow rates the code had problems in simulating the amount of the water remaining in the pump elbow, but in general the agreement between the calculated results and the experimental data was good. (orig.)

Mechanical Behaviour of Glassy Composite Seals for IT-SOFC Application

DEFF Research Database (Denmark)

Nielsen, Karsten Agersted; Solvang, Mette; Nielsen, Sofie Birkedal Lund

2007-01-01

Glass-based sealants have been developed with emphasis on filler material and surface treatment of the sealing components in order to optimise their mechanical and functional behaviour during the initial sealing process as well as during thermal cycling of the SOFC-stack after exposure to operating...... conditions. The bonding strength and microstructure of the interfaces between composite seals and interconnect materials were investigated as a function of surface treatment of the sealing surfaces, glass matrix composition, sealing pressure and temperature. The initial sealing performance and resistance...... to thermal cycling were then investigated on selected combinations of materials after ageing. Strongest bonding between sodium aluminosilicate glass composite and steel surfaces was obtained for sealing at 850°C. For the strongest interface, having shear strength of 2.35 MPa, rupture occurred in the glass...

ASTUS system for verifying the transport seal TITUS 1

International Nuclear Information System (INIS)

Barillaux; Monteil, D.; Destain, G.D.

1991-01-01

ASTUS, a system for acquisition and processing ultrasonic signatures of TITUS 1 seals has been developed. TITUS seals are used to verify the integrity of the fissile material's container sealing after transport. An autonomous portable reading case permit to take seals signatures at the starting point and to transmit these reference signatures to a central safeguards computer by phonic modem. Then, at the terminal point with a similar reading case, an authority takes again the signature of seals and immediately transmit these signatures to the central safeguards computer. The central computer processes the data in real time by autocorrelation and return its verdict to the terminal point

Crashworthy sealed pressure vessel for plutonium transport

International Nuclear Information System (INIS)

Andersen, J.A.