9 CFR 381.98 - Official seal.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Official seal. 381.98 Section 381.98... Certificates; Certification Procedures § 381.98 Official seal. The official mark for use in sealing means of... and a serial number as shown below, and any seals approved by the Administrator for applying such mark...

9 CFR 381.98 - Official seal.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 9 Animals and Animal Products 2 2011-01-01 2011-01-01 false Official seal. 381.98 Section 381.98... Certificates; Certification Procedures § 381.98 Official seal. The official mark for use in sealing means of... and a serial number as shown below, and any seals approved by the Administrator for applying such mark...

Airborne nanoparticle concentrations in the manufacturing of polytetrafluoroethylene (PTFE) apparel.

PubMed

Vosburgh, Donna J H; Boysen, Dane A; Oleson, Jacob J; Peters, Thomas M

2011-03-01

One form of waterproof, breathable apparel is manufactured from polytetrafluoroethylene (PTFE) membrane laminated fabric using a specific process to seal seams that have been sewn with traditional techniques. The sealing process involves applying waterproof tape to the seam by feeding the seam through two rollers while applying hot air (600 °C). This study addressed the potential for exposure to particulate matter from this sealing process by characterizing airborne particles in a facility that produces more than 1000 lightweight PTFE rain jackets per day. Aerosol concentrations throughout the facility were mapped, breathing zone concentrations were measured, and hoods used to ventilate the seam sealing operation were evaluated. The geometric mean (GM) particle number concentrations were substantially greater in the sewing and sealing areas (67,000 and 188,000 particles cm⁻³)) compared with that measured in the office area (12,100 particles cm⁻³). Respirable mass concentrations were negligible throughout the facility (GM = 0.002 mg m⁻³) in the sewing and sealing areas). The particles exiting the final discharge of the facility's ventilation system were dominated by nanoparticles (number median diameter = 25 nm; geometric standard deviation of 1.39). The breathing zone particle number concentrations of the workers who sealed the sewn seams were highly variable and significantly greater when sealing seams than when conducting other tasks (p < 0.0001). The sealing workers' breathing zone concentrations ranged from 147,000 particles cm⁻³ to 798,000 particles cm⁻³, and their seam responsibility significantly influenced their breathing zone concentrations (p = 0.03). The finding that particle number concentrations were approximately equal outside the hood and inside the local exhaust duct indicated poor effectiveness of the canopy hoods used to ventilate sealing operations.

Airborne Nanoparticle Concentrations in the Manufacturing of Polytetrafluoroethylene (PTFE) Apparel

PubMed Central

Vosburgh, Donna J.H.; Boysen, Dane A.; Oleson, Jacob J.; Peters, Thomas M.

2016-01-01

One form of waterproof, breathable apparel is manufactured from polytetrafluoroethylene (PTFE) membrane laminated fabric, using a specific process to seal seams that have been sewn with traditional techniques. The sealing process involves applying waterproof tape to the seam by feeding the seam through two rollers while applying hot air (600°C). This study addressed the potential for exposure to particulate matter from this sealing process, by characterizing airborne particles in a facility that produces over 1,000 lightweight PTFE rain jackets per day. Aerosol concentrations throughout the facility were mapped, breathing zone concentrations were measured, and hoods used to ventilate the seam sealing operation were evaluated. The geometric mean (GM) particle number concentrations were substantially greater in the sewing and sealing areas (67,000 and 188,000 particles cm−3) compared to that measured in the office area (12,100 particles cm−3). Respirable mass concentrations were negligible throughout the facility (GM=0.002 mg m−3 in the sewing and sealing areas). The particles exiting the final discharge of the facility's ventilation system were dominated by nanoparticles (number median diameter = 25 nm; geometric standard deviation of 1.39). The breathing zone particle number concentrations of the workers who sealed the sewn seams were highly variable and significantly greater when sealing seams than when conducting other tasks (p<0.0001). The sealing workers’ breathing zone concentrations ranged from 147,000 particles cm−3 to 798,000 particles cm−3, and their seam responsibility significantly influenced their breathing zone concentrations (p=0.03). The finding that particle number concentrations were approximately equal outside the hood and inside the local exhaust duct indicated poor effectiveness of the canopy hoods used to ventilate sealing operations. PMID:21347955

Intestinal helminths of a landlocked ringed seal (Phoca hispida saimensis) population in eastern Finland.

PubMed

Sinisalo, Tuula; Kunnasranta, Mervi; Valtonen, E Tellervo

2003-09-01

A small, landlocked, endangered ringed seal (Phoca hispida saimensis) population lives as a postglacial relict in Lake Saimaa in eastern Finland. In this study, the intestinal metazoans were examined from a total of 61 Saimaa seals found dead from 1981 to 2001. The helminth fauna was very depauperate. Only one acanthocephalan species, Corynosoma magdaleni, has been able to survive during isolation in the freshwater environment. In addition, only two cestode species were found: Diphyllobothrium ditretum and Schistocephalus sp. However, neither of these larvae developed in the ringed seals. As the newborn pups of Saimaa seals are nursed for about 2 months only one of them was infected by C. magdaleni. At 2-5 months the pups harboured worms; however, the mean intensity did not rise distinctively until the seals were adults. C. magdaleni infection increased with increasing age and the abundances were significantly different between the age groups. There was no correlation between the number of parasites and the adult seal body weight; however, seals weighing 36 kg or more carried the majority of the worms. The distribution of the parasites was aggregated; six seals carried 65% (n=1,182) of all worms (total n=1,809) and 26 seals were uninfected. Variation in the number of worms in individual seals may indicate differences in feeding behaviour and in the diet of seals, and/or variation in the immune status of the seals.

19 CFR 24.13a - Car, compartment, and package seals; and fastenings; standards; acceptance by Customs.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 19 Customs Duties 1 2014-04-01 2014-04-01 false Car, compartment, and package seals; and... PROCEDURE § 24.13a Car, compartment, and package seals; and fastenings; standards; acceptance by Customs. (a... identification number on the seal. (2) If the seal is to be used by private industry (i.e., a shipper...

19 CFR 24.13a - Car, compartment, and package seals; and fastenings; standards; acceptance by Customs.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 19 Customs Duties 1 2013-04-01 2013-04-01 false Car, compartment, and package seals; and... PROCEDURE § 24.13a Car, compartment, and package seals; and fastenings; standards; acceptance by Customs. (a... identification number on the seal. (2) If the seal is to be used by private industry (i.e., a shipper...

19 CFR 24.13a - Car, compartment, and package seals; and fastenings; standards; acceptance by Customs.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 19 Customs Duties 1 2012-04-01 2012-04-01 false Car, compartment, and package seals; and... PROCEDURE § 24.13a Car, compartment, and package seals; and fastenings; standards; acceptance by Customs. (a... identification number on the seal. (2) If the seal is to be used by private industry (i.e., a shipper...

Early-life sexual segregation: ontogeny of isotopic niche differentiation in the Antarctic fur seal

NASA Astrophysics Data System (ADS)

Kernaléguen, L.; Arnould, J. P. Y.; Guinet, C.; Cazelles, B.; Richard, P.; Cherel, Y.

2016-09-01

Investigating the ontogeny of niche differentiation enables to determine at which life-stages sexual segregation arises, providing insights into the main factors driving resource partitioning. We investigated the ontogeny of foraging ecology in Antarctic fur seals (Arctocephalus gazella), a highly dimorphic species with contrasting breeding strategies between sexes. Sequential δ13C and δ15N values of whiskers provided a longitudinal proxy of the foraging niche throughout the whole life of seals, from weaning, when size dimorphism is minimal to the age of 5. Females exhibited an early-life ontogenetic shift, from a total segregation during their first year at-sea, to a similar isotopic niche as breeding females as early as age 2. In contrast, males showed a progressive change in isotopic niche throughout their development such that 5-year-old males did not share the same niche as territorial bulls. Interestingly, males and females segregated straight after weaning with males appearing to feed in more southerly habitats than females. This spatial segregation was of similar amplitude as observed in breeding adults and was maintained throughout development. Such early-life niche differentiation is an unusual pattern and indicates size dimorphism and breeding constraints do not directly drive sexual segregation contrary to what has been assumed in otariid seals.

Flow induced force of labyrinth seal

NASA Technical Reports Server (NTRS)

Iwatsubo, T.; Motooka, N.; Kawai, R.

1982-01-01

Flow induced instability force due to a labyrinth seal is analyzed. An approximate solution is given for the partial differential equation representing the flow in labyrinth seal and it is compared with the finite difference method in order to verify the accuracy of both methods. The effects of difference of inlet and outlet pressures of the seal, deflection of pressure and mass flow from the steady state, rotor diameter, seal clearance, seal interval and seal number on the flow induced force of the seal are investigated and it is known that some of these factors are very influential on the flow induced force.

Compressible and incompressible fluid seals: Influence on rotordynamic response and stability

NASA Technical Reports Server (NTRS)

Thames, Howard D.

1992-01-01

The flow field inside a whirling annular seal operating a Reynolds numbers of 12,000 and 24,000 and a Taylor number of 6,600 was measured. The rotor was mounted eccentric (50 percent) upon the facilities shaft which resulted in a circular orbit at a whirl ratio of 1.0. Three papers which summarize the work were written and are presented. Addition measurements were performed for the annular seal operating at an eccentricity ratio of 10 percent for Re = 24,000 and Ta = 6,600. A labyrinth seal was also installed into the facility and operated at an eccentricity ratio of 50 percent at the same Reynolds and Taylor numbers. These data are currently being reduced and analyzed.

Eccentricity effects upon the flow field inside a whirling annular seal

NASA Technical Reports Server (NTRS)

Morrison, Gerald L.; Deotte, Robert E., Jr.; Das, Purandar G.; Thames, H. Davis

1994-01-01

The flow field inside a whirling annular seal operating at a Reynolds number of 24,000 and a Taylor number of 6600 has been measured using a 3-D laser Doppler anemometer system. Two eccentricity ratios were considered, 0.10 and 0.50. The seal has a diameter of 164 mm, is 37.3 mm long, and has a clearance of 1.27 mm. The rotor was mounted eccentrically on the shaft such that the whirl ratio is 1.0 and the rotor follows a circular orbit. The mean axial velocity is not uniform around the circumference of the seal; near the inlet a region characterized by high velocity of the seal. By the exit, another region of high axial velocity is not uniform around the circumference of the seal; near the inlet a region characterized by high velocity of the seal. By the exit, another region of high axial velocity has developed, this time on the suction side of the seal. The magnitude and azimuthal distance of the migration increased with increasing whirl amplitude (eccentricity). Throughout the seal length, the azimuthal mean velocity varied inversely with the mean axial velocity. Increasing the whirl amplitude did not increase the magnitude of the azimuthal velocity at the seal exit.

Effectiveness of crack sealing on pavement serviceability and life.

DOT National Transportation Integrated Search

2011-06-01

This report presents the details of a study to evaluate effectiveness of Ohio Department of Transportations prevailing crack sealing program. Evaluation was performed through field monitoring a large number of crack sealed and control sections. Fi...

Process for disposing of radioactive wastes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grantham, L.F.; Gray, R.L.; McCoy, L.R.

1988-05-03

A process for removing water from the pores of spent, contaminated radioactive ion exchange resins and encasing radionuclides entrapped within the pores of the resins, the process is described consisting essentially of the sequential steps of: (a) heating the spent ion exchange resins at a temperature of from about 100/sup 0/C to about 150/sup 0/C to remove water from within and fill the pores of the ion exchange resins by heating the ion exchange resins for from about 46 to about 610 hours at a temperature at which the pores of the resins are sealed while avoiding any fusing ormore » melting of the ion exchange resins to encase radionuclides contained within the resins; and (b) cooling the resins to obtain dry, flowable ion exchange resins having radionuclides encased within sealed polymeric spheres.« less

A novel cause of rebreathing carbon dioxide related to removed CLIC-seal on the Dräger Apollo© anesthesia machine.

PubMed

Niknam, B; Bebic, Z; Roseman, A

2018-05-26

We present a case report involving two sequential, surgically uneventful, laparoscopic cholecystectomies using the same anesthesia machine (Drager Apollo©) for which the level of inspired carbon dioxide was noted to be elevated following various diagnostic interventions including replacing the sodalime, increasing fresh gas flows, and a full inspection of equipment for malfunction. Eventually it was discovered that a rubber ring seal connecting the Dragersorb CLIC system© to the sodalime canister was inadvertently removed during the initial canister exchange resulting in an apparent bypassing of the absorbent and thus an inability of the exhaled gas to contact the sodalime. To our knowledge this is the first such description of this potential cause of elevated inspired carbon dioxide and should warrant consideration when other conventional interventions have failed.

Continuous Manufacturing of Nitrocellulose by Magnesium Nitrate Method. Volume 1

DTIC Science & Technology

1979-06-01

enters a scrubber . The scrubber removes entrained acid, water, and NC fines from the air before it enters a Roots water sealed (lobe type) vacuum pump...and is exhausted to the atmosphere. The air enters the bottom of the scrubber and is forced (by vacuum) sequentially through two weir arrangements...the panel from left to right, the Eimco dewatering filter drive, vacuum pressure, receiver, vacuum scrubber , and pump controls may be seen along with

Design of a Two Dimensional Planer Pressurized Air Labyrinth Seal Test Rig

DTIC Science & Technology

1993-12-01

identity by block number) Dump Diffuser, Flow Modification, Laser Doppler Velocimeter, Labyrinth Seal , Leakage Prediction, Press --ized air 19 Abstract...reducing this high to low pressure leakage . Figure 1.1 is a two dimensional representation of a 3 dimensional annular labyrinth seal . The object of this... Labyrinth Seal literature, Sneck [2] credits C.A. Parsons with development of the labyrinth seal in concert with Parson’s [31 development of the steam

Sealing Penetrating Eye Injuries with Photoactivated Bonding

DTIC Science & Technology

2012-09-01

light treatment parameters for sealing a variety of penetrating eye wounds and have demonstrated that these repair procedures are safe to ocular...AWARD NUMBER: W81XWH-09-2-0050 TITLE: Sealing Penetrating Eye Injuries with Photoactivated...TYPE Final 3. DATES COVERED (From - To) 1 Sep 2009-31 Aug 2012 4. TITLE AND SUBTITLE Sealing Penetrating Eye Injuries with Photoactivated Bonding

Performance of strip seals in Iowa bridges, pilot study.

DOT National Transportation Integrated Search

2001-01-01

A pilot study was conducted on the premature failures of neoprene strip seals in : expansion joints in Iowa bridges. In a relatively large number of bridges, strip seals have : pulled out of the steel extrusions or otherwise failed well before the ex...

Training Young Children on Sequential Relations among Numbers and Spatial Decomposition: Differential Transfer to Number Line and Mental Transformation Tasks

ERIC Educational Resources Information Center

Xu, Chang; LeFevre, Jo-Anne

2016-01-01

Are there differential benefits of training sequential number knowledge versus spatial skills for children's numerical and spatial performance? Three- to five-year-old children (N = 84) participated in 1 session of either sequential training (e.g., what comes before and after the number 5?) or non-numerical spatial training (i.e., decomposition of…

Static and dynamic characteristics of parallel-grooved seals

NASA Technical Reports Server (NTRS)

Iwatsubo, Takuzo; Yang, Bo-Suk; Ibaraki, Ryuji

1987-01-01

Presented is an analytical method to determine static and dynamic characteristics of annular parallel-grooved seals. The governing equations were derived by using the turbulent lubrication theory based on the law of fluid friction. Linear zero- and first-order perturbation equations of the governing equations were developed, and these equations were analytically investigated to obtain the reaction force of the seals. An analysis is presented that calculates the leakage flow rate, the torque loss, and the rotordynamic coefficients for parallel-grooved seals. To demonstrate this analysis, we show the effect of changing number of stages, land and groove width, and inlet swirl on stability of the boiler feed water pump seals. Generally, as the number of stages increased or the grooves became wider, the leakage flow rate and rotor-dynamic coefficients decreased and the torque loss increased.

Overview of studies to determine injury caused by the Exxon Valdez Oil Spill to marine mammals

USGS Publications Warehouse

Loughlin, Thomas R.; Ballachey, Brenda E.; Wright, B.A.; Rice, S.D.; Spies, R.B.; Wolfe, D.A.; Wright, B.A.

1996-01-01

Marine mammal damage assessment studies after the Exxon Valdez oil spill concentrated on sea otters, harbor seals, Steller sea lions, killer whales, and humpback whales. Sea otter and harbor seals were the most affected marine mammal; it was estimated that several thousand otters and several hundred harbor seals died within months of the spill. Steller sea lion, harbor seal, and sea otter numbers were monitored using aerial surveys. Studies of humpback whales and killer whales used photoidentification techniques to determine changes in abundance, distribution, mortality, and natality. Tissues from animals found dead in spill and control areas were analyzed for hydrocarbon levels. Sea otters, sea lions and harbor seals had elevated hydrocarbon levels, but only sea otters and harbor seals showed population declines associated with the spill. Humpback whales were not severely affected by the Exxon Valdez oil spill. Killer whale numbers in the resident AB pod declined after the spill. Coincidental evidence supports the oil spill as the causative agent.

Preliminary Analysis of Automatic Speech Recognition and Synthesis Technology.

DTIC Science & Technology

1983-05-01

16.311 % a. Seale In/Se"l tAL4 lrs e y i s 2 I ROM men "Ig eddiei, m releerla ons leveltc. Ŗ dots ghoeea INDtISTRtAIJ%6LITARY SPEECH SYNTHESIS PRODUCTS...saquence The SC-01 Suech Syntheszer conftains 64 cf, arent poneme~hs which are accessed try A 6-tht code. 1 - the proper sequ.enti omthnatiors of thoe...connected speech input with widely differing emotional states, diverse accents, and substantial nonperiodic background noise input. As noted previously

Development of flow systems by direct-milling on poly(methyl methacrylate) substrates using UV-photopolymerization as sealing process.

PubMed

Rodrigues, Eunice R G O; Lapa, Rui A S

2009-03-01

An alternative process for the design and construction of fluidic devices is presented. Several sealing processes were studied, as well as the hydrodynamic characteristics of the proposed fluidic devices. Manifolds were imprinted on polymeric substrates by direct-write milling, according to Computer Assisted Design (CAD) data. Poly(methyl methacrylate) (PMMA) was used as substrate due to its physical and chemical properties. Different bonding approaches for the imprinted channels were evaluated and UV-photopolymerization of acrylic acid (AA) was selected. The hydrodynamic characteristics of the proposed flow devices were assessed and compared to those obtained in similar flow systems using PTFE reactors and micro-pumps as propulsion units (multi-pumping approach). The applicability of the imprinted reactors was evaluated in the sequential determination of calcium and magnesium in water samples. Results obtained were in good agreement with those obtained by the reference procedure.

Mechanics of Re-Torquing in Bolted Flange Connections

NASA Technical Reports Server (NTRS)

Gordon, Ali P.; Drilling Brian; Weichman, Kyle; Kammerer, Catherine; Baldwin, Frank

2010-01-01

It has been widely accepted that the phenomenon of time-dependent loosening of flange connections is a strong consequence of the viscous nature of the compression seal material. Characterizing the coupled interaction between gasket creep and elastic bolt stiffness has been useful in predicting conditions that facilitate leakage. Prior advances on this sub-class of bolted joints has lead to the development of (1) constitutive models for elastomerics, (2) initial tightening strategies, (3) etc. The effect of re-torque, which is a major consideration for typical bolted flange seals used on the Space Shuttle fleet, has not been fully characterized, however. The current study presents a systematic approach to characterizing bolted joint behavior as the consequence of sequentially applied torques. Based on exprimenta1 and numerical results, the optimal re-torquing parameters have been identified that allow for the negligible load loss after pre-load application

Restorations in abrasion/erosion cervical lesions: 8-year results of a triple blind randomized controlled trial.

PubMed

Dall'Orologio, Giovanni Dondi; Lorenzi, Roberta

2014-10-01

An equivalence randomized controlled trial within the subject was organized to evaluate the clinical long-term success of a new 2-step etch & rinse adhesive and a new nano-filled ormocer. 50 subjects, 21 males and 29 females aged between 21 and 65, were randomized to receive 150 restorations, 100 with the new restorative material, 50 with the composite as control, placed in non-carious cervical lesions with the same bonding system. The main outcome measure was the cause of failure at 8 years. Randomization was number table-generated, with allocation concealment by opaque sequentially numbered sealed and stapled envelopes. Subjects, examiner, and analyst were blinded to group assignment. Two interim analyses were performed. Data were analyzed by ANOVA and Cox test (P < 0.05). After 8 years, 40 subjects and 120 teeth were included in the analysis of the primary outcome. There were eight failures in the experimental group and four failures in the control group. The cumulative loss rate was 7% for both restorative materials, with the annual failure lower than 1%, without any statistically significant difference. There were two key elements of failure: the presence of sclerotic dentin and the relationship between lesion and gingival margin.

Apparatus for removing a contaminant from a fluid stream

DOEpatents

Brewster, M.D.; Posa, R.P.

1998-12-22

A device for removing a contaminant from a fluid stream flowing within a conduit is disclosed. The device includes a container and a barrier. The container has a first wall generated about an axis and a second wall generated about the same axis. The first wall defines a first volume therewithin, while the first and second walls define an annular second volume therebetween. Both the first and second volumes are sealed at one end of the device, while at the other end of the device the second volume only is sealed. A filter material occupies the second volume. The first and second walls are permeable to the fluid stream and are capable of retaining the filter material in the second volume. The barrier is impermeable to the fluid stream and creates a seal between the second wall and the conduit wall. The barrier is positioned adjacent the other end of the device such that when the other end of the device is the upstream end, the fluid stream must sequentially pass into the first volume, through the first wall, into the second volume and through the filter material, and through the second wall. 4 figs.

Apparatus for removing a contaminant from a fluid stream

DOEpatents

Brewster, Michael D.; Posa, Richard P.

1998-01-01

A device for removing a contaminant from a fluid stream flowing within a conduit is disclosed. The device includes a container and a barrier. The container has a first wall generated about an axis and a second wall generated about the same axis. The first wall defines a first volume therewithin, while the first and second walls define an annular second volume therebetween. Both the first and second volumes are sealed at one end of the device, while at the other end of the device the second volume only is sealed. A filter material occupies the second volume. The first and second walls are permeable to the fluid stream and are capable of retaining the filter material in the second volume. The barrier is impermeable to the fluid stream and creates a seal between the second wall and the conduit wall. The barrier is positioned adjacent the other end of the device such that when the other end of the device is the upstream end, the fluid stream must sequentially pass into the first volume, through the first wall, into the second volume and through the filter material, and through the second wall.

Advanced solid electrolyte cell for CO2 and H2O electrolysis. [for extended duration manned spaceflights

NASA Technical Reports Server (NTRS)

Shumar, J. W.; Berger, T. A.

1978-01-01

A solid electrolyte cell with improved sealing characteristics was examined. A tube cell was designed, developed, fabricated, and tested. Design concepts incorporated in the tube cell to improve its sealing capability included minimizing the number of seals per cell and moving seals to lower temperature regions. The advanced tube cell design consists of one high temperature ceramic cement seal, one high temperature gasket seal, and three low temperature silicone elastomer seals. The two high temperature seals in the tube cell design represent a significant improvement over the ten high temperature precious metal seals required by the electrolyzer drum design. For the tube cell design the solid electrolyte was 8 mole percent yttria stabilized zirconium oxide slip cast into the shape of a tube with electrodes applied on the inside and outside surfaces.

A fully sealed plastic chip for multiplex PCR and its application in bacteria identification.

PubMed

Xu, Youchun; Yan, He; Zhang, Yan; Jiang, Kewei; Lu, Ying; Ren, Yonghong; Wang, Hui; Wang, Shan; Xing, Wanli

2015-07-07

Multiplex PCR is an effective tool for simultaneous multiple target detection but is limited by the intrinsic interference and competition among primer pairs when it is performed in one reaction tube. Dividing a multiplex PCR into many single PCRs is a simple strategy to overcome this issue. Here, we constructed a plastic, easy-to-use, fully sealed multiplex PCR chip based on reversible centrifugation for the simultaneous detection of 63 target DNA sequences. The structure of the chip is quite simple, which contains sine-shaped infusing channels and a number of reaction chambers connecting to one side of these channels. Primer pairs for multiplex PCR were sequentially preloaded in the different reaction chambers, and the chip was enclosed with PCR-compatible adhesive tape. For usage, the PCR master mix containing a DNA template is pipetted into the infusing channels and centrifuged into the reaction chambers, leaving the infusing channels filled with air to avoid cross-contamination of the different chambers. Then, the chip is sealed and placed on a flat thermal cycler for PCR. Finally, amplification products can be detected in situ using a fluorescence scanner or recovered by reverse centrifugation for further analyses. Therefore, our chip possesses two functions: 1) it can be used for multi-target detection based on end-point in situ fluorescence detection; and 2) it can work as a sample preparation unit for analyses that need multiplex PCR such as hybridization and target sequencing. The performance of this chip was carefully examined and further illustrated in the identification of 8 pathogenic bacterial genomic DNA samples and 13 drug-resistance genes. Due to simplicity of its structure and operation, accuracy and generality, high-throughput capacity, and versatile functions (i.e., for in situ detection and sample preparation), our multiplex PCR chip has great potential in clinical diagnostics and nucleic acid-based point-of-care testing.

Exploratory Development of New and Improved Self-Sealing Materials for Fuel Lines

DTIC Science & Technology

1974-10-01

identify hy block number) New and improved self-sealing fuel line composites were developed under this program. Fabric reinforced plastic and nonflowering...integrated aluminum foil, fabric reinforced laminated fuel line composites employing compressed natural rubber foam as the sealant were fabricated which...successfully sealed wounds inflicted by .30 and .50 caliber projectiles. The weight of these new self-sealing fuel line composites ranged from 0.83

Protein Crystal Growth Apparatus for Microgravity

NASA Technical Reports Server (NTRS)

Carter, Daniel C. (Inventor); Dowling, Timothy E. (Inventor)

1997-01-01

Apparatus for growing protein crystals under microgravity environment includes a plurality of protein growth assemblies stacked one above the other within a canister. Each of the protein growth assemblies includes a tray having a number of spaced apart growth chambers recessed below an upper surface. the growth chambers each having an upstanding pedestal and an annular reservoir about the pedestal for receiving a wick and precipitating agents. A well is recessed below the top of each pedestal to define a protein crystal growth receptacle. A flexible membrane is positioned on the upper surface of each tray and a sealing plate is positioned above each membrane, each sealing plate having a number of bumpers corresponding in number and alignment to the pedestals for forcing the membrane selectively against the upper end of the respective pedestal to seal the reservoir and the receptacle when the sealing plate is forced down.

77 FR 27718 - Marine Mammals; File No. 15453

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-11

... Rossiter, Responsible Party), to conduct research on and enhancement of captive Hawaiian monk seals... by the applicant to increase the number of seals to be maintained under the proposed permit (from two to three seals). The requested permit has been issued under the authority of the Marine Mammal...

[Effect of a "Like!" seal on the stress reactions of nurses in a hospital].

PubMed

Yoshida, Eri; Yamada, Kazuko; Morioka, Ikuharu

2016-01-01

Improving the work environment is effective as a primary measure against mental health disorders. The aim of this study was to verify the hypothesis that using a "Like!" seal would promote friendly relations in the workplace, and reduce the stress reactions of nurses in a hospital. The "Like!" seal was inspired by "Thanks" cards conveying appreciation mutually, "OK" cards conveying the recognition of good points, and the "Like" button frequently used in social networking services. The subjects were 362 nurses working in a university hospital, of whom, 156 (43.1%) permitted the use of data collected before and after the intervention. A total of 151 (41.7%) subjects were analyzed. The intervention using the "Like!" seal lasted 8 weeks. The controls were 105 nurses who answered the same questionnaire in the same hospital and who permitted the use of the collected data. The question items comprised: basic attributes, the Brief Job Stress Questionnaire, the Sense of Coherence (SOC) scale, the Brief Scales for Coping Profile (BSCP), the lifestyles (HPI), and the number of uses of the "Like!" seal. To examine the effects of the intervention, a two-way analysis of variance was performed. To examine the factors related to changed psychological symptoms, a multiple linear regression analysis (stepwise method) was performed with the variation as the dependent variable. The number of uses of the "Like!" seal was 7,010 seals in total, and 19.4 seals on average per nurse. Many seals read phrases showing thanks and/or approval. Psychological symptoms showed a significant interaction. The scores increased in the intervention group after the intervention, but showed no change in the control group. Among the subscales of SOC, manageability showed a significant interaction. Increased scores were found in the intervention group after the intervention, but there was no change in the control group. Multiple linear regression analysis revealed that two factors were related to the variation of psychological symptoms. They were: the variation of manageability, and the number of seals used per nurse. The "Like!" seal which encourages mutual conveyance of feelings of thanks and/or approval has the potential to reduce the stress reactions of nurses.

Experimental and numerical determination of the static critical pressure in ferrofluid seals

NASA Astrophysics Data System (ADS)

Horak, W.; Szczęch, M.

2013-02-01

Ferrofluids have various engineering applications; one of them are magnetic fluid seals for rotating shafts. There are various constructions of this type of seals, but the main difference is the number of sealing stages. The development of this construction is a complex process which requires knowledge of ferrofluid physical and rheological properties and the magnetic field distribution inside the sealing gap. One of the most important parameters of ferrofluid seals is the critical (burst) pressure. It is the pressure value at which a leak will occur. This study presents results of numerical simulation of magnetic field distribution inside the seal gap and calculations of the critical pressure value. The obtained pressure values were verified by experiments.

77 FR 35993 - Agency Information Collection Activities: Cargo Container and Road Vehicle Certification for...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-15

... Activities: Cargo Container and Road Vehicle Certification for Transport Under Customs Seal AGENCY: U.S... Paperwork Reduction Act: Cargo Container and Road Vehicle for Transport under Customs Seal. This is a.... Title: Cargo Container and Road Vehicle for Transport under Customs Seal. OMB Number: 1651-0124. Form...

Methodology for the in vitro evaluation of the delivery efficiency from valved holding chambers with facemasks.

PubMed

Xu, Zhen; Hsu, Wenchi; von Hollen, Dirk; Viswanath, Ashwin; Nikander, Kurt; Dalby, Richard

2014-08-01

In vitro performance studies of valved holding chamber (VHC)-facemask systems are a cost-effective means of circumventing potentially confounding clinical variables. This article reports results of an in vitro investigation into VHC-facemask performance, using three age-specific soft anatomical model (SAM) faces, under clinically relevant conditions. A potentially standardized method was developed to assess VHC-facemask seal leakage, and evaluate the in vitro delivery efficiency of conventional and antistatic VHC-facemask systems. A custom-built test rig and VHC cradles were used to position the VHC-facemask systems against the SAM faces, with a constant, reproducible force. A standardized simulated pediatric breathing pattern (tidal volume = 155 mL; inhalation:exhalation ratio = 40:60; 25 breaths/min) was utilized. Percent facemask seal leakage, percent delivered dose, and the effect of different numbers of simulated breaths (2 to 8) were investigated. Of the VHC-facemask systems tested, the OptiChamber Diamond VHC with LiteTouch facemask (Diamond) system had the lowest percent seal leakage with each SAM face. Percent seal leakage from the other VHC-facemask systems was similar with SAM0 and SAM2 faces; the AeroChamber Plus Z-Stat VHC with ComfortSeal facemask (AC Z-Stat) system had a substantially greater percent seal leakage with the SAM1 face. Regardless of the number of simulated breaths, the Diamond system delivered the greatest mean percent delivered dose, with the lowest coefficient of variation, with each SAM face. Percent delivered dose did not correlate well with seal leakage, particularly for VHC-facemask systems with high seal leakage. The electrostatic properties of the VHCs appeared to influence drug delivery. This study describes a potentially standardized method for the evaluation of VHC-facemask systems. Use of this method enabled a comprehensive investigation into the influence of clinically relevant variables, including age-specific facial anatomy, number of simulated breaths, and seal leakage, on the delivery efficiency of several commercially available VHC-facemask systems.

Hermetic edge sealing of photovoltaic modules

NASA Astrophysics Data System (ADS)

1983-02-01

The edge sealing technique is accomplished by a combination of a chemical bond between glass and aluminum, formed by electrostatic bonding, and a metallurgical bond between aluminum and aluminum, formed by ultrasonic welding. Such a glass to metal seal promises to provide a low cost, long lifetime, highly effective hermetic seal which can protect module components from severe environments. Development of the sealing techniques and demonstration of their effectiveness by fabricating a small number of dummy modules, up to eight inches square in size, and testing them for hermeticity using helium leak testing methods are reviewed. Non-destructive test methods are investigated.

Hermetic edge sealing of photovoltaic modules

NASA Technical Reports Server (NTRS)

1983-01-01

The edge sealing technique is accomplished by a combination of a chemical bond between glass and aluminum, formed by electrostatic bonding, and a metallurgical bond between aluminum and aluminum, formed by ultrasonic welding. Such a glass to metal seal promises to provide a low cost, long lifetime, highly effective hermetic seal which can protect module components from severe environments. Development of the sealing techniques and demonstration of their effectiveness by fabricating a small number of dummy modules, up to eight inches square in size, and testing them for hermeticity using helium leak testing methods are reviewed. Non-destructive test methods are investigated.

Corkscrew Seals: Grey Seal (Halichoerus grypus) Infanticide and Cannibalism May Indicate the Cause of Spiral Lacerations in Seals

PubMed Central

2016-01-01

Large numbers of dead seals with characteristic spiral lesions have been washing ashore around the North Atlantic over the past two decades. Interactions with ship propellers and shark predation have been suggested as the likely causal mechanisms. However, new evidence points towards a more likely candidate: grey seal predation. An adult male grey seal was observed and recorded catching, killing and eating five weaned grey seal pups over a period of one week on the Isle of May, Scotland. A further 9 carcasses found in the same area exhibited similar injuries. Post mortem analysis of lesions indicated the wound characteristics were similar to each other and in 12 of the 14 carcasses analysed, were indistinguishable from carcasses previously attributed to propeller interaction. We therefore propose that most of the seal carcasses displaying spiral lacerations in the UK are caused by grey seal predation. Cases in other locations should be re-evaluated using the scoring system presented here to identify whether grey seal predation is a major cause of mortality in phocid seals. PMID:27254025

Corkscrew Seals: Grey Seal (Halichoerus grypus) Infanticide and Cannibalism May Indicate the Cause of Spiral Lacerations in Seals.

PubMed

Brownlow, Andrew; Onoufriou, Joseph; Bishop, Amanda; Davison, Nicholas; Thompson, Dave

2016-01-01

Large numbers of dead seals with characteristic spiral lesions have been washing ashore around the North Atlantic over the past two decades. Interactions with ship propellers and shark predation have been suggested as the likely causal mechanisms. However, new evidence points towards a more likely candidate: grey seal predation. An adult male grey seal was observed and recorded catching, killing and eating five weaned grey seal pups over a period of one week on the Isle of May, Scotland. A further 9 carcasses found in the same area exhibited similar injuries. Post mortem analysis of lesions indicated the wound characteristics were similar to each other and in 12 of the 14 carcasses analysed, were indistinguishable from carcasses previously attributed to propeller interaction. We therefore propose that most of the seal carcasses displaying spiral lacerations in the UK are caused by grey seal predation. Cases in other locations should be re-evaluated using the scoring system presented here to identify whether grey seal predation is a major cause of mortality in phocid seals.

19 CFR 18.4 - Sealing conveyances and compartments; labeling packages; warning cards.

Code of Federal Regulations, 2010 CFR

2010-04-01

... the breaking of the seals will be necessary to ventilate the hatches, or in other similar... or label to be affixed to heavy or bulky goods being so transported. If, however, he has reason to... authorized to break these seals. Car or vessel Number or name From To Notice: The merchandise in this car...

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

PubMed

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.

Entrance and exit region friction factor models for annular seal analysis. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Elrod, David Alan

1988-01-01

The Mach number definition and boundary conditions in Nelson's nominally-centered, annular gas seal analysis are revised. A method is described for determining the wall shear stress characteristics of an annular gas seal experimentally. Two friction factor models are developed for annular seal analysis; one model is based on flat-plate flow theory; the other uses empirical entrance and exit region friction factors. The friction factor predictions of the models are compared to experimental results. Each friction model is used in an annular gas seal analysis. The seal characteristics predicted by the two seal analyses are compared to experimental results and to the predictions of Nelson's analysis. The comparisons are for smooth-rotor seals with smooth and honeycomb stators. The comparisons show that the analysis which uses empirical entrance and exit region shear stress models predicts the static and stability characteristics of annular gas seals better than the other analyses. The analyses predict direct stiffness poorly.

Current prevalence of adult Uncinaria spp. in northern fur seal (Callorhinus ursinus) and California sea lion (Zalophus californianus) pups on San Miguel Island, California, with notes on the biology of these hookworms.

PubMed

Lyons, E T; Melin, S R; DeLong, R L; Orr, A J; Gulland, F M; Tolliver, S C

2001-06-28

A prevalence survey for hookworms (Uncinaria spp.) was done in northern fur seal (Callorhinus ursinus) and California sea lion (Zalophus californianus) pups on San Miguel Island, CA, in 2000. Intestines of dead pups were examined for adult hookworms in July. These parasites were found in 95% of 20 fur seal pups and 100% of 31 sea lion pups. The number of hookworms varied from 4 to 2142 (mean = 760) in fur seal pups and from 20 to 2634 (mean = 612) in sea lion pups. A direct relationship was evident between body condition and number of hookworms in the pups; that is, pups in poor condition had fewer hookworms than those in good condition. There was a decline in the number of hookworms in sea lion pups in 2000 compared to collections in 1996. Eggs of Uncinaria spp. were found in rectal feces (collected in late September and early October) of none of 35 (0%) live fur seal pups and 41 of 48 (85%) live sea lion pups. Packed cell volume values, determined for most of the same live pups, were essentially normal for C. ursinus but were much lower than normal for most Z. californianus. Hookworm larvae were not found in blubber of fur seal and sea lion pups or in rookery sand in July. Rookery sand, positive for live hookworm larvae when put in a refrigerator, was negative at removal 2.5 years later. The average number of eggs in utero of female hookworms was 285 for three specimens from a fur seal pup and 281 from three specimens from a sea lion pup. One hookworm larva was recovered from milk stripped from the teats of a stranded Z. californianus female at The Marine Mammal Center, Sausalito, CA.

An Overview of Advanced Elastomeric Seal Development and Testing Capabilities at NASA Glenn Research Center

NASA Technical Reports Server (NTRS)

Dunlap, Patrick H., Jr.

2014-01-01

NASA is developing advanced space-rated elastomeric seals to support future space exploration missions to low Earth orbit, the Moon, near Earth asteroids, and other destinations. This includes seals for a new docking system and vehicle hatches. These seals must exhibit extremely low leak rates to ensure that astronauts have sufficient breathable air for extended missions. Seal compression loads must be below prescribed limits so as not to overload the mechanisms that compress them, and seal adhesion forces must be low to allow the sealed interface to be separated when required (e.g., during undocking or hatch opening). NASA Glenn Research Center has developed a number of unique test fixtures to measure the leak rates and compression and adhesion loads of candidate seal designs under simulated thermal, vacuum, and engagement conditions. Tests can be performed on fullscale seals with diameters on the order of 50 in., subscale seals that are about 12 in. in diameter, and smaller specimens such as O-rings. Test conditions include temperatures ranging from -238 to 662degF (-150 to 350degC), operational pressure gradients, and seal-on-seal or seal-on-flange mating configurations. Nominal and off-nominal conditions (e.g., incomplete seal compression) can also be simulated. This paper describes the main design features and capabilities of each type of test apparatus and provides an overview of advanced seal development activities at NASA Glenn.

An Overview of Advanced Elastomeric Seal Development and Testing Capabilities at NASA Glenn Research Center

NASA Technical Reports Server (NTRS)

Dunlap, Patrick H.

2014-01-01

NASA is developing advanced space-rated elastomeric seals to support future space exploration missions to low Earth orbit, the Moon, near Earth asteroids, and other destinations. This includes seals for a new docking system and vehicle hatches. These seals must exhibit extremely low leak rates to ensure that astronauts have sufficient breathable air for extended missions. Seal compression loads must be below prescribed limits so as not to overload the mechanisms that compress them, and seal adhesion forces must be low to allow the sealed interface to be separated when required (e.g., during undocking or hatch opening). NASA Glenn Research Center has developed a number of unique test fixtures to measure the leak rates and compression and adhesion loads of candidate seal designs under simulated thermal, vacuum, and engagement conditions. Tests can be performed on full-scale seals with diameters on the order of 50 in., subscale seals that are about 12 in. in diameter, and smaller specimens such as O-rings. Test conditions include temperatures ranging from -238 to 662 F (-150 to 350 C), operational pressure gradients, and seal-on-seal or seal-on-flange mating configurations. Nominal and off-nominal conditions (e.g., incomplete seal compression) can also be simulated. This paper describes the main design features and capabilities of each type of test apparatus and provides an overview of advanced seal development activities at NASA Glenn.

Endoparasitic helminths of the harbour seal, Phoca vitulina, in the Netherlands

NASA Astrophysics Data System (ADS)

Borgsteede, F. H. M.; Bus, H. G. J.; Verplanke, J. A. W.; van Burg, W. P. J.

The endoparasitic helminth fauna of harbour seals which had died during the epidemic of the phocine distemper virus in 1988 was studied. Lungs, heart and gastrointestinal tracts of 94 animals collected along the Dutch coast were available for investigation. The following parasites and infection percentages were found: Nematoda: Dipetalonema spirocauda (24.5%), Otostrongylus circumlitus (6.4%), Parafilaroides gymnurus (24.5%), Ascaridoidea spec. (58.5%); Trematoda: Phagicola septentrionalis (66.0%), Cryptocotyle lingua (74.5%); Cestoda: Diphyllobothrium spec. (8.5%); Acanthocephala: Corynosoma strumosum (70.2%). The presence of worm species was not evenly distributed over the age classes. Seals younger than one year harboured fewer parasites. The highest percentages were found in 1 to 2 year old seals. The number of worms per seal varied greatly. The highest burden for ascarids was 253, for P. septentrionalis 123 000, for C. lingua 112 000 and for C. strumosum 251. A comparison of the present results with those described in the literature shows that in Dutch seals the same species were present and that numbers of worms were not higher than before the 1988 mass mortality. It is therefore concluded that helminth parasites did not cause the mass mortality.

A Comparative Morphometric Analysis of Three Cranial Nerves in Two Phocids: The Hooded Seal (Cystophora cristata) and the Harbor Seal (Phoca vitulina).

PubMed

Wohlert, Dennis; Kröger, Jürgen; Witt, Martin; Schmitt, Oliver; Wree, Andreas; Czech-Damal, Nicole; Siebert, Ursula; Folkow, Lars; Hanke, Frederike D

2016-03-01

While our knowledge about the senses of pinnipeds has increased over the last decades almost nothing is known about the organization of the neuroanatomical pathways. In a first approach to this field of research, we assessed the total number of myelinated axons of three cranial nerves (CNs) in the harbor (Phoca vitulina, Pv) and hooded seal (Cystophora cristata, Cc). Axons were counted in semithin sections of the nerves embedded in Epon and stained with toluidine blue. In both species, the highest axon number was found within the optic nerve (Pv 187,000 ± 8,000 axons, Cc 481,600 ± 1,300 axons). Generally, considering absolute axon numbers, far more axons were counted within the optic and trigmenial nerve (Pv 136,700 ± 2,500 axons, Cc 179,300 ± 6,900 axons) in hooded in comparison to harbor seals. The axon counts of the vestibulocochlear nerve are nearly identical for both species (Pv 87,100 ± 8,100 axons, Cc 86,600 ± 2,700 axons). However, when comparing cell density, the cell density is almost equal for all nerves for both species except for the optic nerve in which cell density was particularly higher than in the other nerves and higher in hooded in comparison to harbor seals. We here present the first comparative analysis of three CNs in two phocid seals. While the CNs of these closely related species share some general characteristics, pronounced differences in axon numbers/densities are apparent. These differences seem to reflect differences in e.g. size, habitat, and/or functional significance of the innervated sensory systems. © 2015 Wiley Periodicals, Inc.

SSME seal test program: Test results for smooth, hole-pattern and helically-grooved stators

NASA Technical Reports Server (NTRS)

Childs, Dara W.

1987-01-01

All of the listed seals were tested in a liquid Halon test facility at high Reynolds numbers. In addition, a helically-grooved-stator seal was tested in an air seal facility. An analysis of the test results with comparisons to theoretical predictions supports the following conclusions: (1) For small seals, the Hirs' friction-factor model is more restricted than had been thought; (2) For smooth seals, predictions of stiffness and damping improve markedly as the radical clearance is reduced; (3) Friction-factor data for hole-pattern-seal stators frequently deviates from the Hirs model; (4) Predictions of stiffness and damping coefficients for hole-pattern-stator seals is generally reasonable; (5) Tests for the hole-pattern stators at reduced clearances show no clear optimum for hole-pattern seals with respect to either hole-area ratio or hole depth to minimum clearance ratios; (6) Tests of these hole-pattern stators show no significant advantage in net damping over smooth seals; (7) Tests of helically-grooved seal stators in Halon show reasonable agreement between theory and prediction for leakage and direct stiffness but poor agreement for the net damping coefficient.

Socio-metrics: Identifying Invisible Deviant Adversaries

DTIC Science & Technology

2015-12-07

ELEMENT NUMBER 5b. GRANT NUMBER 5a. CONTRACT NUMBER Form Approved OMB NO. 0704-0188 3 . DATES COVERED (From - To) - UU UU UU UU 07-12-2015 1-Oct-2013 30...collaborate each other in conducting cyber-attacks at an unprecedented scale [ 3 ]. Monitoring OSNs and Internet forums is thus imperative to understand and...Socia/SEAL and in Section 3 , we present the results of using Socia/SEAL on data collected from real-world OSNs. Section 4 concludes this report

Wall Shear Stress, Wall Pressure and Near Wall Velocity Field Relationships in a Whirling Annular Seal

NASA Technical Reports Server (NTRS)

Morrison, Gerald L.; Winslow, Robert B.; Thames, H. Davis, III

1996-01-01

The mean and phase averaged pressure and wall shear stress distributions were measured on the stator wall of a 50% eccentric annular seal which was whirling in a circular orbit at the same speed as the shaft rotation. The shear stresses were measured using flush mounted hot-film probes. Four different operating conditions were considered consisting of Reynolds numbers of 12,000 and 24,000 and Taylor numbers of 3,300 and 6,600. At each of the operating conditions the axial distribution (from Z/L = -0.2 to 1.2) of the mean pressure, shear stress magnitude, and shear stress direction on the stator wall were measured. Also measured were the phase averaged pressure and shear stress. These data were combined to calculate the force distributions along the seal length. Integration of the force distributions result in the net forces and moments generated by the pressure and shear stresses. The flow field inside the seal operating at a Reynolds number of 24,000 and a Taylor number of 6,600 has been measured using a 3-D laser Doppler anemometer system. Phase averaged wall pressure and wall shear stress are presented along with phase averaged mean velocity and turbulence kinetic energy distributions located 0.16c from the stator wall where c is the seal clearance. The relationships between the velocity, turbulence, wall pressure and wall shear stress are very complex and do not follow simple bulk flow predictions.

Pulsatile release of biomolecules from polydimethylsiloxane (PDMS) chips with hydrolytically degradable seals.

PubMed

Intra, Janjira; Glasgow, Justin M; Mai, Hoang Q; Salem, Aliasger K

2008-05-08

We demonstrate, for the first time, a robust novel polydimethylsiloxane (PDMS) chip that can provide controlled pulsatile release of DNA based molecules, proteins and oligonucleotides without external stimuli or triggers. The PDMS chip with arrays of wells was constructed by replica molding. Poly(lactic acid-co-glycolic acid) (PLGA) polymer films of varying composition and thickness were used as seals to the wells. The composition, molecular weight and thickness of the PLGA films were all parameters used to control the degradation rate of the seals and therefore the release profiles. Degradation of the films followed the PLGA composition order of 50:50 PLGA>75:25 PLGA>85:15 PLGA at all time-points beyond week 1. Scanning electron microscopy images showed that films were initially smooth, became porous and ruptured as the osmotic pressure pushed the degrading PLGA film outwards. Pulsatile release of DNA was controlled by the composition and thickness of the PLGA used to seal the well. Transfection experiments in a model Human Embryonic Kidney 293 (HEK293) cell line showed that plasmid DNA loaded in the wells was functional after pulsatile release in comparison to control plasmid DNA at all time-points. Thicker films degraded faster than thinner films and could be used to fine-tune the release of DNA over day length periods. Finally the PDMS chip was shown to provide repeated sequential release of CpG oligonucleotides and a model antigen, Ovalbumin (OVA), indicating significant potential for this device for vaccinations or applications that require defined complex release patterns of a variety of chemicals, drugs and biomolecules.

Optimal Sequential Rules for Computer-Based Instruction.

ERIC Educational Resources Information Center

Vos, Hans J.

1998-01-01

Formulates sequential rules for adapting the appropriate amount of instruction to learning needs in the context of computer-based instruction. Topics include Bayesian decision theory, threshold and linear-utility structure, psychometric model, optimal sequential number of test questions, and an empirical example of sequential instructional…

Prevalence and molecular characterisation of Acanthocephala in pinnipedia of the North and Baltic Seas.

PubMed

Waindok, Patrick; Lehnert, Kristina; Siebert, Ursula; Pawliczka, Iwona; Strube, Christina

2018-04-01

Harbour seals ( Phoca vitulina ) and grey seals ( Halichoerus grypus ) are final hosts of acanthocephalans in the German North and Baltic Seas. Parasitic infections in seals can cause pathological changes, which may result in deteriorated health of the host. Common gastrointestinal parasites of harbour and grey seals are acanthocephalans and a number of 275 of 2460 (11.2%) investigated seals from 1996 to 2013 were infected with Corynosoma spp. (Acanthocephala, Polymorphidae). The prevalence showed a wave-like pattern: it increased from 1.2% and 0.4% in 1996 and 1997, respectively, to 23.9% during the second phocine distemper epizootic in 2002 and decreased to 6.2% in 2004. In 2005, prevalence peaked again with 25.0% followed by a decrease to 9.3% in 2009 and an increase to 38.5% in 2012. Statistical analysis revealed that harbour seals originating from the North Sea showed a higher prevalence than grey seals, whereas no significant difference between grey and harbour seals from the Baltic Sea was observed. Furthermore, juvenile pinnipedia from the North Sea were significantly less infected with Corynosoma spp. than seals older than seven month. Molecular species identification as well as phylogenetic relationship analysis among the detected Corynosoma species were achieved by sequencing and comparisons of the ribosomal ITS1-5.8S-ITS2-complex and cytochrome-c-oxidase I gene. Molecular analysis resulted in a newly arranged distribution of Acanthocephala in the North Sea as in contrast to previous studies, C. strumosum could not be confirmed as predominant species. Instead, C. magdaleni and a C. magdaleni isolate (isolate Pv1NS) with an atypical number of longitudinal rows of hooks at the proboscis were detected. Furthermore, morphological and molecular analyses indicate the possible finding of a cryptic species (Candidatus Corynosoma nortmeri sp. nov.).

Vibrissal touch sensing in the harbor seal (Phoca vitulina): how do seals judge size?

PubMed

Grant, Robyn; Wieskotten, Sven; Wengst, Nina; Prescott, Tony; Dehnhardt, Guido

2013-06-01

"Whisker specialists" such as rats, shrews, and seals actively employ their whiskers to explore their environments and extract object properties such as size, shape, and texture. It has been suggested that whiskers could be used to discriminate between different sized objects in one of two ways: (i) to use whisker positions, such as angular position, spread or amplitude to approximate size; or (ii) to calculate the number of whiskers that contact an object. This study describes in detail how two adult harbor seals use their whiskers to differentiate between three sizes of disk. The seals judged size very fast, taking <400 ms. In addition, they oriented their smaller, most rostral, ventral whiskers to the disks, so that more whiskers contacted the surface, complying to a maximal contact sensing strategy. Data from this study supports the suggestion that it is the number of whisker contacts that predict disk size, rather than how the whiskers are positioned (angular position), the degree to which they are moved (amplitude) or how spread out they are (angular spread).

Viscoelastic analysis of seals for extended service life

NASA Technical Reports Server (NTRS)

Bower, Mark V.

1993-01-01

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

Accounting for Test Variability through Sizing Local Domains in Sequential Design Optimization with Concurrent Calibration-Based Model Validation

DTIC Science & Technology

2013-08-01

in Sequential Design Optimization with Concurrent Calibration-Based Model Validation Dorin Drignei 1 Mathematics and Statistics Department...Validation 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Dorin Drignei; Zissimos Mourelatos; Vijitashwa Pandey

Sequential megafaunal collapse in the North Pacific Ocean: An ongoing legacy of industrial whaling?

USGS Publications Warehouse

Springer, A.M.; Estes, J.A.; Van Vliet, Gus B.; Williams, T.M.; Doak, D.F.; Danner, E.M.; Forney, K.A.; Pfister, B.

2003-01-01

Populations of seals, sea lions, and sea otters have sequentially collapsed over large areas of the northern North Pacific Ocean and southern Bering Sea during the last several decades. A bottom-up nutritional limitation mechanism induced by physical oceanographic change or competition with fisheries was long thought to be largely responsible for these declines. The current weight of evidence is more consistent with top-down forcing. Increased predation by killer whales probably drove the sea otter collapse and may have been responsible for the earlier pinniped declines as well. We propose that decimation of the great whales by post-World War II industrial whaling caused the great whales' foremost natural predators, killer whales, to begin feeding more intensively on the smaller marine mammals, thus "fishing-down" this element of the marine food web. The timing of these events, information on the abundance, diet, and foraging behavior of both predators and prey, and feasibility analyses based on demographic and energetic modeling are all consistent with this hypothesis.

Sequential megafaunal collapse in the North Pacific Ocean: An ongoing legacy of industrial whaling?

PubMed Central

Springer, A. M.; Estes, J. A.; van Vliet, G. B.; Williams, T. M.; Doak, D. F.; Danner, E. M.; Forney, K. A.; Pfister, B.

2003-01-01

Populations of seals, sea lions, and sea otters have sequentially collapsed over large areas of the northern North Pacific Ocean and southern Bering Sea during the last several decades. A bottom-up nutritional limitation mechanism induced by physical oceanographic change or competition with fisheries was long thought to be largely responsible for these declines. The current weight of evidence is more consistent with top-down forcing. Increased predation by killer whales probably drove the sea otter collapse and may have been responsible for the earlier pinniped declines as well. We propose that decimation of the great whales by post-World War II industrial whaling caused the great whales' foremost natural predators, killer whales, to begin feeding more intensively on the smaller marine mammals, thus “fishing-down” this element of the marine food web. The timing of these events, information on the abundance, diet, and foraging behavior of both predators and prey, and feasibility analyses based on demographic and energetic modeling are all consistent with this hypothesis. PMID:14526101

Separator plate for a fuel cell

DOEpatents

Petri, R.J.; Meek, J.; Bachta, R.P.; Marianowski, L.G.

1996-04-02

A separator plate is described for a fuel cell comprising an anode current collector, a cathode current collector and a main plate, the main plate disposed between the anode current collector and the cathode current collector. The anode current collector forms a flattened peripheral wet seal structure and manifold wet seal structure on the anode side of the separator plate and the cathode current collector forms a flattened peripheral wet seal structure and manifold wet seal structure on the cathode side of the separator plate. In this manner, the number of components required to manufacture and assemble a fuel cell stack is reduced. 9 figs.

Separator plate for a fuel cell

DOEpatents

Petri, Randy J.; Meek, John; Bachta, Robert P.; Marianowski, Leonard G.

1996-01-01

A separator plate for a fuel cell comprising an anode current collector, a cathode current collector and a main plate, the main plate disposed between the anode current collector and the cathode current collector. The anode current collector forms a flattened peripheral wet seal structure and manifold wet seal structure on the anode side of the separator plate and the cathode current collector forms a flattened peripheral wet seal structure and manifold wet seal structure on the cathode side of the separator plate. In this manner, the number of components required to manufacture and assemble a fuel cell stack is reduced.

Integrated main rail, feed rail, and current collector

DOEpatents

Petri, Randy J.; Meek, John; Bachta, Robert P.; Marianowski, Leonard G.

1994-01-01

A separator plate for a fuel cell comprising an anode current collector, a cathode current collector and a main plate, the main plate disposed between the anode current collector and the cathode current collector. The anode current collector forms a flattened peripheral wet seal structure and manifold wet seal structure on the anode side of the separator plate and the cathode current collector forms a flattened peripheral wet seal structure and manifold wet seal structure on the cathode side of the separator plate. In this manner, the number of components required to manufacture and assemble a fuel cell stack is reduced.

Life and Utilization Criteria Identification in Design (LUCID). Volume 1

DTIC Science & Technology

1981-10-01

stator, seal /spacer, etc. weights are added to these rotor weights in estimating module weights. Weights of other engine modules (combustor, augmentor...of turbine airfoil/platform cooling air and disk cooling/ seal leakage air), number of vanes and blades for the single stage high-pressure turbine, and...subroutines include hubs, shafts, seals and spacers in estimating rotor weights. Module weight is estimated by adding case and stator weights to the rotor

Application of Pinniped Vibrissae to Aeropropulsion

NASA Technical Reports Server (NTRS)

Shyam, Vikram; Ameri, Ali; Poinsatte, Philip; Thurman, Douglas; Wroblewski, Adam; Snyder, Christopher

2015-01-01

Vibrissae of Phoca Vitulina (Harbor Seal) and Mirounga Angustirostris (Elephant Seal) possessundulations along their length. Harbor Seal Vibrissae were shown to reduce vortex induced vibrations and reduce dragcompared to appropriately scaled cylinders and ellipses. Samples of Harbor Seal vibrissae, Elephant Seal vibrissae andCalifornia Sea Lion vibrissae were collected from the Marine Mammal Center in California. CT scanning, microscopy and3D scanning techniques were utilized to characterize the whiskers. Computational fluid dynamics simulations of thewhiskers were carried out to compare them to an ellipse and a cylinder. Leading edge parameters from the whiskerswere used to create a 3D profile based on a modern power turbine blade. The NASA SW-2 facility was used to performwind tunnel cascade testing on the 'Seal Blades'. Computational Fluid Dynamics simulations were used to studyincidence angles from -37 to +10 degrees on the aerodynamic performance of the Seal Blade. The tests and simulationswere conducted at a Reynolds number of 100,000. The Seal Blades showed consistent performance improvements overthe baseline configuration. It was determined that a fuel burn reduction of approximately 5 could be achieved for a fixedwing aircraft. Noise reduction potential is also explored

Evaluation of new plastic compression (Ziegler) type of seals for long life planetary batteries

NASA Technical Reports Server (NTRS)

Frank, H. A.

1973-01-01

A program was initiated to develop improved types of terminal seals for aerospace Ni-Cd batteries. The approach used has not involved attempts, such as employed elsewhere, to improve the ceramic-to-metal seal that is now extensively employed for this application. Rather the approach has been directed toward the development and evaluation of new types of seals. Of prime interest in this initial investigation has been the Ziegler type of compression seal and in particular the injection molded version developed by the Bell Telephone Laboratories (BTL). A number of these units were designed, fabricated, and evaluated on an accelerated life test under a simulated battery environment. Results have shown that there are no major problems involved in scaling up the BTL small-size (5-amp) seal to a larger size (up to 50-amp) seal suitable for most JPL flight batteries. Five out of five such seals successfully completed over 10 months of continuous thermal cycling without developing any leaks greater than 1.8 x to 10 to the minus 9th power atm-cc-He/s.

Reusable, tamper-indicating seal

DOEpatents

Ryan, Michael J.

1978-01-01

A reusable, tamper-indicating seal comprises a drum confined within a fixed body and rotatable in one direction therewithin, the top of the drum constituting a tray carrying a large number of small balls of several different colors. The fixed body contains parallel holes for looping a seal wire therethrough. The base of the drums carries cams adapted to coact with cam followers to lock the wire within the seal at one angular position of the drum. A channel in the fixed body -- visible from outside the seal -- adjacent the tray constitutes a segregated location for a small plurality of the colored balls. A spring in the tray forces colored balls into the segregated location at one angular position of the drum, further rotation securing the balls in position and the wires in the seal. A wedge-shaped plough removes the balls from the segregated location, at a different angular position of the drum, the wire being unlocked at the same position. A new pattern of colored balls will appear in the segregated location when the seal is relocked.

Perilymph Kinetics of FITC-Dextran Reveals Homeostasis Dominated by the Cochlear Aqueduct and Cerebrospinal Fluid.

PubMed

Salt, A N; Gill, R M; Hartsock, J J

2015-06-01

Understanding how drugs are distributed in perilymph following local applications is important as local drug therapies are increasingly used to treat disorders of the inner ear. The potential contribution of cerebrospinal fluid (CSF) entry to perilymph homeostasis has been controversial for over half a century, largely due to artifactual contamination of collected perilymph samples with CSF. Measures of perilymph flow and of drug distribution following round window niche applications have both suggested a slow, apically directed flow occurs along scala tympani (ST) in the normal, sealed cochlea. In the present study, we have used fluorescein isothiocyanate-dextran as a marker to study perilymph kinetics in guinea pigs. Dextran is lost from perilymph more slowly than other substances so far quantified. Dextran solutions were injected from pipettes sealed into the lateral semicircular canal (SCC), the cochlear apex, or the basal turn of ST. After varying delays, sequential perilymph samples were taken from the cochlear apex or lateral SCC, allowing dextran distribution along the perilymphatic spaces to be quantified. Variability was low and findings were consistent with the injection procedure driving volume flow towards the cochlear aqueduct, and with volume flow during perilymph sampling driven by CSF entry at the aqueduct. The decline of dextran with time in the period between injection and sampling was consistent with both a slow volume influx of CSF (~30 nL/min) entering the basal turn of ST at the cochlear aqueduct and a CSF-perilymph exchange driven by pressure-driven fluid oscillation across the cochlear aqueduct. Sample data also allowed contributions of other processes, such as communications with adjacent compartments, to be quantified. The study demonstrates that drug kinetics in the basal turn of ST is complex and is influenced by a considerable number of interacting processes.

Sequential analysis in neonatal research-systematic review.

PubMed

Lava, Sebastiano A G; Elie, Valéry; Ha, Phuong Thi Viet; Jacqz-Aigrain, Evelyne

2018-05-01

As more new drugs are discovered, traditional designs come at their limits. Ten years after the adoption of the European Paediatric Regulation, we performed a systematic review on the US National Library of Medicine and Excerpta Medica database of sequential trials involving newborns. Out of 326 identified scientific reports, 21 trials were included. They enrolled 2832 patients, of whom 2099 were analyzed: the median number of neonates included per trial was 48 (IQR 22-87), median gestational age was 28.7 (IQR 27.9-30.9) weeks. Eighteen trials used sequential techniques to determine sample size, while 3 used continual reassessment methods for dose-finding. In 16 studies reporting sufficient data, the sequential design allowed to non-significantly reduce the number of enrolled neonates by a median of 24 (31%) patients (IQR - 4.75 to 136.5, p = 0.0674) with respect to a traditional trial. When the number of neonates finally included in the analysis was considered, the difference became significant: 35 (57%) patients (IQR 10 to 136.5, p = 0.0033). Sequential trial designs have not been frequently used in Neonatology. They might potentially be able to reduce the number of patients in drug trials, although this is not always the case. What is known: • In evaluating rare diseases in fragile populations, traditional designs come at their limits. About 20% of pediatric trials are discontinued, mainly because of recruitment problems. What is new: • Sequential trials involving newborns were infrequently used and only a few (n = 21) are available for analysis. • The sequential design allowed to non-significantly reduce the number of enrolled neonates by a median of 24 (31%) patients (IQR - 4.75 to 136.5, p = 0.0674).

Uncinariasis in northern fur seal and California sea lion pups from California.

PubMed

Lyons, E T; DeLong, R L; Melin, S R; Tolliver, S C

1997-10-01

Northern fur seal (Callorhinus ursinus) (n = 25) and California sea lion (Zalophus californianus) (n = 53) pups, found dead on rookeries on San Miguel Island (California, USA), were examined for adult Uncinaria spp. Prevalence of these nematodes was 96% in fur seal pups and 100% in sea lion pups. Mean intensity of Uncinaria spp. per infected pup was 643 in fur seals and 1,284 in sea lions. Eggs of Uncinaria spp. from dead sea lion pups underwent embryonation in an incubator; development to the free-living third stage larva occurred within the egg. This study provided some specific information on hookworm infections in northern fur seal and California sea lion pups on San Miguel Island. High prevalence rate of Uncinaria spp. in both species of pinnipeds was documented and much higher numbers (2X) of hookworms were present in sea lion than fur seal pups.

Method and apparatus for active tamper indicating device using optical time-domain reflectometry

DOEpatents

Smith, D. Barton; Muhs, Jeffrey D.; Pickett, Chris A.; Earl, D. Duncan

1999-01-01

An optical time-domain reflectometer (OTDR) launches pulses of light into a link or a system of multiplexed links and records the waveform of pulses reflected by the seals in the link(s). If a seal is opened, the link of cables will become a discontinuous transmitter of the light pulses and the OTDR can immediately detect that a seal has been opened. By analyzing the waveform, the OTDR can also quickly determine which seal(s) were opened. In this way the invention functions as a system of active seals. The invention is intended for applications that require long-term surveillance of a large number of closures. It provides immediate tamper detection, allows for periodic access to secured closures, and can be configured for many different distributions of closures. It can monitor closures in indoor and outdoor locations and it can monitor containers or groups of containers located many kilometers apart.

Cortical responses following simultaneous and sequential retinal neurostimulation with different return configurations.

PubMed

Barriga-Rivera, Alejandro; Morley, John W; Lovell, Nigel H; Suaning, Gregg J

2016-08-01

Researchers continue to develop visual prostheses towards safer and more efficacious systems. However limitations still exist in the number of stimulating channels that can be integrated. Therefore there is a need for spatial and time multiplexing techniques to provide improved performance of the current technology. In particular, bright and high-contrast visual scenes may require simultaneous activation of several electrodes. In this research, a 24-electrode array was suprachoroidally implanted in three normally-sighted cats. Multi-unit activity was recorded from the primary visual cortex. Four stimulation strategies were contrasted to provide activation of seven electrodes arranged hexagonally: simultaneous monopolar, sequential monopolar, sequential bipolar and hexapolar. Both monopolar configurations showed similar cortical activation maps. Hexapolar and sequential bipolar configurations activated a lower number of cortical channels. Overall, the return configuration played a more relevant role in cortical activation than time multiplexing and thus, rapid sequential stimulation may assist in reducing the number of channels required to activate large retinal areas.

Experimental Studies of Premixed Flame Structure and Propagation Characteristics in Compressible Flow

DTIC Science & Technology

2015-07-14

turbulence has not been addressed experimentally. These issues are important for next generation high-pressure gas turbine , and especially, for scramjet...subsonic wind tunnel capable of Mach numbers in excess of Mach 0.7, with the ability to generate varying turbulence levels and accommodate fuel injection...square O- ring stock seal mounted in the corners to aid in locating the individual seals and window panes, as well as RTV silicone gasket seal galleries

Climate change and the northern elephant seal (Mirounga angustirostris) population in Baja California, Mexico.

PubMed

García-Aguilar, María C; Turrent, Cuauhtémoc; Elorriaga-Verplancken, Fernando R; Arias-Del-Razo, Alejandro; Schramm, Yolanda

2018-01-01

The Earth's climate is warming, especially in the mid- and high latitudes of the Northern Hemisphere. The northern elephant seal (Mirounga angustirostris) breeds and haul-outs on islands and the mainland of Baja California, Mexico, and California, U.S.A. At the beginning of the 21st century, numbers of elephant seals in California are increasing, but the status of Baja California populations is unknown, and some data suggest they may be decreasing. We hypothesize that the elephant seal population of Baja California is experiencing a decline because the animals are not migrating as far south due to warming sea and air temperatures. Here we assessed population trends of the Baja California population, and climate change in the region. The numbers of northern elephant seals in Baja California colonies have been decreasing since the 1990s, and both the surface waters off Baja California and the local air temperatures have warmed during the last three decades. We propose that declining population sizes may be attributable to decreased migration towards the southern portions of the range in response to the observed temperature increases. Further research is needed to confirm our hypothesis; however, if true, it would imply that elephant seal colonies of Baja California and California are not demographically isolated which would pose challenges to environmental and management policies between Mexico and the United States.

The fat and the furriest: morphological changes in harp seal fur with ontogeny.

PubMed

Gmuca, Natalia V; Pearson, Linnea E; Burns, Jennifer M; Liwanag, Heather E M

2015-01-01

Ontogenetic changes in physiological performance often exemplify the development of adaptations to environmental challenges. For mammals in polar regions, the extreme cold of the environment presents a constant challenge to thermal homeostasis. The harp seal (Pagophilus groenlandicus) is an Arctic species that shifts its thermoregulatory strategy with ontogeny. Adult harp seals primarily use blubber for insulation, but newborn harp seals instead rely on their fur coat while their blubber layer develops. Harp seal pups are weaned abruptly, less than 2 wk after birth, and must subsequently learn to swim and dive in frigid waters on their own. This study examined how the morphological characteristics of harp seal fur change with ontogeny. We compared hair length, hair circularity, and hair density for neonates (1 d old; n = 7), early-nursing pups (4 d old; n = 3), late-nursing pups (9 d old; n = 4), newly weaned (molting) pups (2 wk old; n = 5), late-weaned (molted) pups (3 wk old; n = 4), and adult harp seals (n = 4). Hairs were shorter (P < 0.001) and flatter (P < 0.001) in older animals. Additionally, hair density decreased with age (P < 0.001), in terms of both the average number of hair bundles per unit area and the average number of underhairs present in any given bundle. These morphological changes were associated with a reduced thermal resistance of the pelt in late-weaned (molted) pups and adults (P < 0.001). Results are consistent with known evolutionary patterns of fur morphology associated with the transition from fur to blubber in aquatic species, yet this is the first time such morphological differences have been demonstrated across age classes within a single species. Thus, the ontogenetic patterns described here for harp seals recapitulate the convergent phylogenetic patterns observed across secondarily aquatic species. Overall, the timing of these ontogenetic changes may limit the ability of harp seals to adapt to the deterioration of sea ice in the Arctic, as predicted with continued climate change.

Integrated main rail, feed rail, and current collector

DOEpatents

Petri, R.J.; Meek, J.; Bachta, R.P.; Marianowski, L.G.

1994-11-08

A separator plate is described for a fuel cell comprising an anode current collector, a cathode current collector and a main plate, the main plate disposed between the anode current collector and the cathode current collector. The anode current collector forms a flattened peripheral wet seal structure and manifold wet seal structure on the anode side of the separator plate and the cathode current collector forms a flattened peripheral wet seal structure and manifold wet seal structure on the cathode side of the separator plate. In this manner, the number of components required to manufacture and assemble a fuel cell stack is reduced. 9 figs.

The New Perilaryngeal Airway (CobraPLA™)1 Is as Efficient as the Laryngeal Mask Airway (LMA™)2, But Provides Better Airway Sealing Pressures

PubMed Central

Akça, Ozan; Wadhwa, Anupama; Sengupta, Papiya; Durrani, Jaleel; Hanni, Keith; Wenke, Mary; Yücel, Yüksel; Lenhardt, Rainer; Doufas, Anthony G.; Sessler, Daniel I.

2006-01-01

The Laryngeal Mask Airway (LMA) is a frequently-used efficient airway device, yet it sometimes seals poorly, thus reducing the efficacy of positive-pressure ventilation. The Perilaryngeal Airway (CobraPLA) is a novel airway device with a larger pharyngeal cuff (when inflated). We tested the hypothesis that the CobraPLA was superior to LMA with regard to insertion time and airway sealing pressure and comparable to LMA in airway adequacy and recovery characteristics. After midazolam and fentanyl, 81 ASA I-II outpatients having elective surgery were randomized to receive an LMA or CobraPLA. Anesthesia was induced with propofol (2.5 mg/kg, IV), and the airway inserted. We measured 1) insertion time; 2) adequacy of the airway (no leak at 15-cm-H2O peak pressure or tidal volume of 5 ml/kg); 3) airway sealing pressure; 4) number of repositioning attempts; and 5) sealing quality (no leak at tidal volume of 8 ml/kg). At the end of surgery, gastric insufflation, postoperative sore throat, dysphonia, and dysphagia were evaluated. Data were compared with unpaired t-tests, chi-square tests, or Fisher’s Exact tests; P<0.05 was significant. Patient characteristics, insertion times, airway adequacy, number of repositioning attempts, and recovery were similar in each group. Airway sealing pressure was significantly greater with CobraPLA (23±6 cm H2O) than LMA (18±5 cm H2O, P<0.001). The CobraPLA has insertion characteristics similar to LMA, but better airway sealing capabilities. PMID:15281543

Pup production, abundance, and breeding distribution of northern elephant seals at San Nicolas Island, winter 1981

USGS Publications Warehouse

1985-01-01

A major breeding colony of northern elephant seals, Mirounga angustirostris, occurs on San Nicolas Island, California. Due to commercial hunting, elephant seals were extinct on San Nicolas Island by the end of the 19th century. Subsequent recovery of the population has been well documented (Table 1). Census data collected since 1949 indicate that the colony has been growing rapidly in numbers after breeding began again in the late 1940s.

Application of Pinniped Vibrissae to Aeropropulsion

NASA Technical Reports Server (NTRS)

Shyam, Vikram (Principal Investigator); Ameri, Ali; Poinsatte, Phil; Thurman, Doug; Wroblewski, Adam; Snyder, Chris

2015-01-01

Vibrissae of Phoca Vitulina (Harbor Seal) and Mirounga Angustirostris (Elephant Seal) possess undulations along their length. Harbor Seal Vibrissae were shown to reduce vortex induced vibrations and reduce drag compared to appropriately scaled cylinders and ellipses. Samples of Harbor Seal vibrissae, Elephant Seal vibrissae and California Sea Lion vibrissae were collected from the Marine Mammal Center in California. CT scanning, microscopy and 3D scanning techniques were utilized to characterize the whiskers. Computational fluid dynamics simulations of the whiskers were carried out to compare them to an ellipse and a cylinder. Leading edge parameters from the whiskers were used to create a 3D profile based on a modern power turbine blade. The NASA SW-2 facility was used to perform wind tunnel cascade testing on the 'Seal Blades'. Computational Fluid Dynamics simulations were used to study incidence angles from -37 to +10 degrees on the aerodynamic performance of the Seal Blade. The tests and simulations were conducted at a Reynolds number of 100,000. The Seal Blades showed consistent performance improvements over the baseline configuration. It was determined that a fuel burn reduction of approximately 5 could be achieved for a fixed wing aircraft. Noise reduction potential is also explored.

50 CFR 216.72 - Restrictions on taking.

Code of Federal Regulations, 2010 CFR

2010-10-01

... discussion of the number of seals expected to be taken annually over the next 3 years to satisfy the subsistence requirements of each island. This discussion will include an assessment of factors and conditions...) St. Paul Island—Seals may only be harvested from the following haulout areas: Zapadni, English Bay...

Some new results concerning the dynamic behavior of annular turbulent seals

NASA Technical Reports Server (NTRS)

Massmann, H.; Nordmann, R.

1985-01-01

The dynamic characteristics of annular turbulent seals applied in high pressure turbopumps can be described by stiffness, damping, and inertia coefficients. An improved procedure is presented for determining these parameters by using measurements made with newly developed test equipment. The dynamic system seal, consisting of the fluid between the cylindrical surfaces of the rotating shaft and the housing, is excited by test forces (input), and the relative motion between the surfaces (output) is measured. Transformation of the input and output time signals into the frequency domain leads to frequency response functions. An analytical model, depending on the seal parameters, is fitted to the measured data in order to identify the dynamic coefficients. Some new results are reported that show the dependencies of these coefficients with respect to the axial and radial Reynolds numbers and the geometrical data of the seal.

Wear simulation of apex seal in rotary engine under mixed lubrication

NASA Astrophysics Data System (ADS)

Jiang, Hanying; Zuo, Zhengxing; Liu, Jinxiang

2018-05-01

In this work, the wear of apex seal's running face under mixed lubrication is studied. Numerical simulation is carried out by employing the couple model of Reynolds equation, Greenwood and Tripp model and Archard's wear law. The simulation is performed both for one circle and multi circle. In the multi circle simulation, the change of contact position due to wear is considered. A method that is able to find the new contact position based on the updated apex seal's contour profile is proposed, validated and used. The result of multi circle simulation indicates that contact position changes obviously around the maximum swing angles both on leading and trailing sides with the increase number of circles. The wear depth distribution becomes more uniform with the increase of operation circle number.

The implications of developments on the Atlantic Frontier for marine mammals

NASA Astrophysics Data System (ADS)

Harwood, John; Wilson, Ben

2001-05-01

We review the available information on the distribution and abundance of marine mammals in the Atlantic Frontier area, and the literature on the potential effects of oil exploration and extraction on these species. Reliable estimates of seal abundance are only available for two species (grey and harbour seals). For grey seals and hooded seals there is also information from telemetry studies on their distribution at sea. Data on cetaceans comes from a variety of sources including whaling statistics, dedicated surveys, observers placed on vessels of opportunity, and from bottom-mounted hydrophone arrays. These indicate that the Atlantic Frontier region is of national, and possibly international, importance for a number of cetacean species. The most abundant small cetacean is likely to be the white-sided dolphin; however, smaller numbers of large whales, including endangered blue, right, fin and sei whales, and vulnerable humpback and sperm whales are also likely to be present in summer. There is growing evidence that a number of marine mammal species respond to the acoustic and physical disturbance associated with exploration for oil and gas resources, although the ecological impact of these responses is unclear. We describe how risk assessment frameworks, initially developed for evaluating the environmental impacts of hazardous chemicals, can be used to address this problem.

S.M.P. SEQUENTIAL MATHEMATICS PROGRAM.

ERIC Educational Resources Information Center

CICIARELLI, V; LEONARD, JOSEPH

A SEQUENTIAL MATHEMATICS PROGRAM BEGINNING WITH THE BASIC FUNDAMENTALS ON THE FOURTH GRADE LEVEL IS PRESENTED. INCLUDED ARE AN UNDERSTANDING OF OUR NUMBER SYSTEM, AND THE BASIC OPERATIONS OF WORKING WITH WHOLE NUMBERS--ADDITION, SUBTRACTION, MULTIPLICATION, AND DIVISION. COMMON FRACTIONS ARE TAUGHT IN THE FIFTH, SIXTH, AND SEVENTH GRADES. A…

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

NASA Astrophysics Data System (ADS)

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) modification; B) eddies displacement and parameters modification (type of eddy, intensity and sign of rotation) as result of climate change; C) relationship between eddies location and whelping rookeries arrangement, climate change and variety of the type of migration; D) stationary eddy as zone of concentration of polluted waters and toxically hazard, climate change and self-cleaning ability; E) spiraling eddies in changing climate and prediction of modification of marine animal welfare.

Theoretical approach to obtaining dynamic characteristics of noncontacting spiral-grooved seals

NASA Technical Reports Server (NTRS)

Iwatsubo, Takuzo; Yang, Bo-Suk; Ibaraki, Ryuji

1987-01-01

The dynamic characteristics of spiral-grooved seals are theoretically obtained by using the Navier-Stokes equation. First, with the inertia term of the fluid considered, the flow and pressure in the steady state are obtained for the directions parallel to and perpendicular to the groove. Next, the dynamic character is obtained by analyzing the steady state and by analyzing the labyrinth seal. As a result, the following conclusions were drawn: (1) As the land width becomes shorter or the helix angle decreases, the cross-coupling stiffness, direct and cross-coupling damping, and add mass coefficients decrease; (2) As the axial Reynolds number increases, the stiffness and damping coefficients increase. But the add mass coefficient is not influenced by the axial Reynolds number; (3) The rotational Reynolds number influences greatly the direct and cross-coupling stiffness and direct damping coefficients; and (4) As the journal rotating frequency increases, the leakage flow decreases. Therefore zero net leakage flow is possible at a particular rotating frequency.

The commercial harvest of ice-associated seals in the Sea of Okhotsk, 1972-1994

PubMed Central

Somov, Aleksandr G.; Burkanov, Vladimir N.; Laidre, Kristin L.; Boveng, Peter L.

2017-01-01

Sealing log books from 75 out of 79 commercial harvest cruises carried out between 1972 and 1994 in the Sea of Okhotsk, Russia, were analyzed to describe spatial and temporal allocation of ice-associated seal harvest effort, species composition of catches, total harvest rates, and related parameters for species including ringed (Pusa hispida), ribbon (Histriophoca fasciata), bearded (Erignathus barbatus) and spotted (Phoca largha) seal. Variations in catch per unit effort were explored in relation to year, sea ice conditions, day of the year, and geographic location. In most years, the harvest was predominantly represented by ringed seals (mean = 0.43, range 0.25–0.67), followed by ribbon (mean = 0.31, range 0.15–0.43), spotted (mean = 0.19, range 0.11–0.35) and bearded seals (mean = 0.07, range 0.03–0.14). The struck-and-lost percentages were as high as 30–35% for ringed, bearded and spotted seals and 15–20% for ribbon seals. Catch per unit effort (number of seals/skiff*day) for ringed, ribbon, and spotted seals had a similar seasonal pattern with a distinct spike in catches for spotted seals in the first week of May, for ribbon seals in the last week of May, and for ringed seals in the second week of June. Catches of bearded seals showed a less pronounced temporal structure with a gradual increase toward the end of the harvest season in the majority of years. Spatial distribution of harvest effort followed closely with seal distribution obtained from aerial surveys. These data could be used as a source of information on seal herd location throughout the breeding and molting seasons and for more complex demographic or life-table models. We did not find any evidence of the decline of catch per unit effort over the study period. Timely introduction of state regulations and efficient harvest management apparently prevented severe depletion of ice-associated seal populations in the Sea of Okhotsk during the periods of their intense exploitation. PMID:28796843

The commercial harvest of ice-associated seals in the Sea of Okhotsk, 1972-1994.

PubMed

Trukhanova, Irina S; Grachev, Aleksey I; Somov, Aleksandr G; Burkanov, Vladimir N; Laidre, Kristin L; Boveng, Peter L

2017-01-01

Sealing log books from 75 out of 79 commercial harvest cruises carried out between 1972 and 1994 in the Sea of Okhotsk, Russia, were analyzed to describe spatial and temporal allocation of ice-associated seal harvest effort, species composition of catches, total harvest rates, and related parameters for species including ringed (Pusa hispida), ribbon (Histriophoca fasciata), bearded (Erignathus barbatus) and spotted (Phoca largha) seal. Variations in catch per unit effort were explored in relation to year, sea ice conditions, day of the year, and geographic location. In most years, the harvest was predominantly represented by ringed seals (mean = 0.43, range 0.25-0.67), followed by ribbon (mean = 0.31, range 0.15-0.43), spotted (mean = 0.19, range 0.11-0.35) and bearded seals (mean = 0.07, range 0.03-0.14). The struck-and-lost percentages were as high as 30-35% for ringed, bearded and spotted seals and 15-20% for ribbon seals. Catch per unit effort (number of seals/skiff*day) for ringed, ribbon, and spotted seals had a similar seasonal pattern with a distinct spike in catches for spotted seals in the first week of May, for ribbon seals in the last week of May, and for ringed seals in the second week of June. Catches of bearded seals showed a less pronounced temporal structure with a gradual increase toward the end of the harvest season in the majority of years. Spatial distribution of harvest effort followed closely with seal distribution obtained from aerial surveys. These data could be used as a source of information on seal herd location throughout the breeding and molting seasons and for more complex demographic or life-table models. We did not find any evidence of the decline of catch per unit effort over the study period. Timely introduction of state regulations and efficient harvest management apparently prevented severe depletion of ice-associated seal populations in the Sea of Okhotsk during the periods of their intense exploitation.

Brush seal numerical simulation: Concepts and advances

NASA Technical Reports Server (NTRS)

Braun, M. J.; Kudriavtsev, V. V.

1994-01-01

The development of the brush seal is considered to be most promising among the advanced type seals that are presently in use in the high speed turbomachinery. The brush is usually mounted on the stationary portions of the engine and has direct contact with the rotating element, in the process of limiting the 'unwanted' leakage flows between stages, or various engine cavities. This type of sealing technology is providing high (in comparison with conventional seals) pressure drops due mainly to the high packing density (around 100 bristles/sq mm), and brush compliance with the rotor motions. In the design of modern aerospace turbomachinery leakage flows between the stages must be minimal, thus contributing to the higher efficiency of the engine. Use of the brush seal instead of the labyrinth seal reduces the leakage flow by one order of magnitude. Brush seals also have been found to enhance dynamic performance, cost less, and are lighter than labyrinth seals. Even though industrial brush seals have been successfully developed through extensive experimentation, there is no comprehensive numerical methodology for the design or prediction of their performance. The existing analytical/numerical approaches are based on bulk flow models and do not allow the investigation of the effects of brush morphology (bristle arrangement), or brushes arrangement (number of brushes, spacing between them), on the pressure drops and flow leakage. An increase in the brush seal efficiency is clearly a complex problem that is closely related to the brush geometry and arrangement, and can be solved most likely only by means of a numerically distributed model.

Seroprevalence of Brucella antibodies in harbor seals in Alaska, USA, with age, regional, and reproductive comparisons.

PubMed

Hoover-Miller, A; Dunn, J L; Field, C L; Blundell, G; Atkinson, S

2017-09-20

Populations of harbor seal Phoca vitulina in the Gulf of Alaska have dramatically declined during the past 4 decades. Numbers of seals in Glacier Bay, in southeast Alaska, USA, have also declined despite extensive protection. Causes of the declines and slow recovery are poorly understood. Brucellosis is a zoonotic disease that adversely affects reproduction in many domestic species. We measured the seroprevalence of Brucella antibodies in 554 harbor seals in 3 Alaska locations: Prince William Sound (PWS), Glacier Bay (GB), and Tracy Arm Fords Terror (TAFT) Wilderness Area. Objectives included testing for regional, sex, age, and female reproductive state differences in Brucella antibody seroprevalence, persistence in titers in recaptured seals, and differences in titers between mother seals and their pups. Overall, 52% of adults (AD), 53% of subadults (SA), 77% of yearlings (YRL), and 26% of <5 mo old pups were seropositive. Matched mother-pup samples were consistent with dependent pups acquiring maternal passive immunity to Brucella. Results show higher seroprevalence (64%) for AD and SA seals in the depressed and declining populations in PWS and GB than in TAFT (29%). Lactating females were less likely to be seropositive than other AD females, including pregnant females. Further research is needed to seek evidence of Brucella infection in Alaskan harbor seals, identify effects on neonatal viability, and assess zoonotic implications for Alaska Natives who rely on harbor seals for food.

9 CFR 98.35 - Declaration, health certificate, and other documents for animal semen.

Code of Federal Regulations, 2012 CFR

2012-01-01

... donor animal as a condition for importing the semen; (7) The seal number on the shipping container; (8... compulsorily notifiable disease; and (ii) An effective surveillance and monitoring system for scrapie is in... shipping containers carrying animal semen for importation into the United States must be sealed with an...

9 CFR 98.35 - Declaration, health certificate, and other documents for animal semen.

Code of Federal Regulations, 2014 CFR

2014-01-01

... donor animal as a condition for importing the semen; (7) The seal number on the shipping container; (8... compulsorily notifiable disease; and (ii) An effective surveillance and monitoring system for scrapie is in... shipping containers carrying animal semen for importation into the United States must be sealed with an...

9 CFR 98.35 - Declaration, health certificate, and other documents for animal semen.

Code of Federal Regulations, 2013 CFR

2013-01-01

... donor animal as a condition for importing the semen; (7) The seal number on the shipping container; (8... compulsorily notifiable disease; and (ii) An effective surveillance and monitoring system for scrapie is in... shipping containers carrying animal semen for importation into the United States must be sealed with an...

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

PubMed

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.

Mitochondrial DNA reveals secondary contact in Japanese harbour seals, the southernmost population in the western Pacific

PubMed Central

Sasaki, Takeshi; Kobayashi, Mari; Haneda, Takayuki; Masubuchi, Takahito

2018-01-01

In this study, we used relatively large number of samples (n = 178) and control region of mtDNA (454bp) to clearify the divergence history of Japanese harbour seals (Phoca vitulina stejnegeri) and phylogenetic relationship between the seals in Japan and other countries. Our results suggested that Japanese harbour seals possibly consisted of more than two lineages and secondary contact of populations after a long isolation. Furthermore, one of the lineage was made only by Japanese harbour seals (Group P1). The proportion of Group P1 was the highest at the South West and gradually decreased towards the North East of Hokkaido, Japan. On the other hand, the haplotypes do not belonged to Group P1 showed close relationship to the seals in the North Pacific. Based on the fossil record of harbour seal in Japan and the range of sea ice during the Last Glacial Maximum (LGM), Group P1 might have entered Japan before the LGM and became isolated due to the geographical boundary, and gradually extended its range from the South West towards the North East of Hokkaido after the disappearance of the sea ice, while the seals which are not in Group P1 immigrated into Japan from the North Pacific. PMID:29385193

A model for the Space Shuttle Main Engine High Pressure Oxidizer Turbopump shaft seal system

NASA Technical Reports Server (NTRS)

Paxson, Daniel E.

1990-01-01

A model of the High Pressure Oxidizer Turbopump (HPOTP) shaft seal system on the Space Shuttle Main Engine (SSME) is described. The model predicts the fluid properties and flow rates throughout this system for a number of conditions simulating failed seals. The results agree well with qualitative expectations and redline values but cannot be verified with actual data due to the lack thereof. The results indicate that each failure mode results in a unique distribution of properties throughout the seal system and can therefore be individually identified given the proper instrumentation. Furthermore, the detection process can be built on the principle of qualitative reasoning without the use of exact fluid property values. A simplified implementation of the model which does not include the slinger/labyrinth seal combination has been developed and will be useful for inclusion in a real-time diagnostic system.

Diverse papillomaviruses identified in Weddell seals.

PubMed

Smeele, Zoe E; Burns, Jennifer M; Van Doorsaler, Koenraad; Fontenele, Rafaela S; Waits, Kara; Stainton, Daisy; Shero, Michelle R; Beltran, Roxanne S; Kirkham, Amy L; Berngartt, Rachel; Kraberger, Simona; Varsani, Arvind

2018-04-01

Papillomaviridae is a diverse family of circular, double-stranded DNA (dsDNA) viruses that infect a broad range of mammalian, avian and fish hosts. While papillomaviruses have been characterized most extensively in humans, the study of non-human papillomaviruses has contributed greatly to our understanding of their pathogenicity and evolution. Using high-throughput sequencing approaches, we identified 7 novel papillomaviruses from vaginal swabs collected from 81 adult female Weddell seals (Leptonychotes weddellii) in the Ross Sea of Antarctica between 2014-2017. These seven papillomavirus genomes were amplified from seven individual seals, and six of the seven genomes represented novel species with distinct evolutionary lineages. This highlights the diversity of papillomaviruses among the relatively small number of Weddell seal samples tested. Viruses associated with large vertebrates are poorly studied in Antarctica, and this study adds information about papillomaviruses associated with Weddell seals and contributes to our understanding of the evolutionary history of papillomaviruses.

Sequential or parallel decomposed processing of two-digit numbers? Evidence from eye-tracking.

PubMed

Moeller, Korbinian; Fischer, Martin H; Nuerk, Hans-Christoph; Willmes, Klaus

2009-02-01

While reaction time data have shown that decomposed processing of two-digit numbers occurs, there is little evidence about how decomposed processing functions. Poltrock and Schwartz (1984) argued that multi-digit numbers are compared in a sequential digit-by-digit fashion starting at the leftmost digit pair. In contrast, Nuerk and Willmes (2005) favoured parallel processing of the digits constituting a number. These models (i.e., sequential decomposition, parallel decomposition) make different predictions regarding the fixation pattern in a two-digit number magnitude comparison task and can therefore be differentiated by eye fixation data. We tested these models by evaluating participants' eye fixation behaviour while selecting the larger of two numbers. The stimulus set consisted of within-decade comparisons (e.g., 53_57) and between-decade comparisons (e.g., 42_57). The between-decade comparisons were further divided into compatible and incompatible trials (cf. Nuerk, Weger, & Willmes, 2001) and trials with different decade and unit distances. The observed fixation pattern implies that the comparison of two-digit numbers is not executed by sequentially comparing decade and unit digits as proposed by Poltrock and Schwartz (1984) but rather in a decomposed but parallel fashion. Moreover, the present fixation data provide first evidence that digit processing in multi-digit numbers is not a pure bottom-up effect, but is also influenced by top-down factors. Finally, implications for multi-digit number processing beyond the range of two-digit numbers are discussed.

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

PubMed

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.

Quantifying Conditions for Fault Self-Sealing in Geologic Carbon Sequestration

NASA Astrophysics Data System (ADS)

McPherson, B. J. O. L.; Patil, V.; Moore, J.; Trujillo, E. M.

2015-12-01

Injecting anthropogenic CO2 into a subsurface reservoir for sequestration will impact the reservoir significantly, including its geochemistry, porosity and permeability. If a fault or fracture penetrates the reservoir, CO2-laden brine may migrate into that fault, eventually sealing it via precipitation or opening it up via dissolution. The goal of this study was to identify and quantify such conditions of fault self-sealing or self-enhancing. We found that the dimensionless Damköhler number (Da), the ratio of reaction rate to advection rate, provides a meaningful framework for characterizing the propensity of (fault) systems to seal or open up. We developed our own framework wherein Damköhler numbers evolve spatiotemporally as opposed to the traditional single Da value approach. Our approach enables us to use the Damköhler for characterization of complex multiphase and multimineral reactive transport problems. We applied this framework to 1D fault models with eight conditions derived from four geologic compositions and two reservoir conditions. The four­ geologic compositions were chosen such that three out of them were representative of distinct geologic end-members (sandstone, mudstone and dolomitic limestone) and one was a mixed composition based on an average of three end-member compositions. The two sets of P-T conditions chosen included one set corresponding to CO2 in a gaseous phase ("shallow conditions") and the other corresponding to supercritical phase CO2 ("deep conditions"). Simulation results suggest that fault sealing via carbonate precipitation was a possibility for shallow conditions within limestone and mixed composition settings. The concentration of cations in the water was found to be an important control on the carbonate precipitation. The deep conditions models did not forecast self-sealing via carbonates. Sealing via clay precipitation is a likely possibility, but the 1000 year time-frame may be short for such. Model results indicated a range of Da values within which substantial reductions of fault porosity (meaning self-sealing) could be expected. A key conclusion suggested by the results of this study is that carbonate precipitation in the near-surface (top ~50-100 m) depths of a fault is the most likely mechanism of "self-sealing" for most geological settings.

77 FR 25209 - Environmental Assessment and Finding of No Significant Impact for Exemption Request for...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-27

... sealed source must either identify the source or device by manufacturer and model number as registered in...., Model Nos. 1862, 1864, and 1866 manual brachytherapy sources for medical uses authorized under the... that do not have an approved Sealed Source and Device Registry (SSDR). The NRC has determined that the...

10 CFR 30.32 - Application for specific licenses.

Code of Federal Regulations, 2011 CFR

2011-01-01

... material in the form of a sealed source or in a device that contains the sealed source must either— (1) Identify the source or device by manufacturer and model number as registered with the Commission under § 32.210 of this chapter, with an Agreement State, or for a source or a device containing radium-226 or...

10 CFR 30.32 - Application for specific licenses.

Code of Federal Regulations, 2010 CFR

2010-01-01

... material in the form of a sealed source or in a device that contains the sealed source must either— (1) Identify the source or device by manufacturer and model number as registered with the Commission under § 32.210 of this chapter, with an Agreement State, or for a source or a device containing radium-226 or...

Adhesion of Silicone Elastomer Seals for NASA's Crew Exploration Vehicle

NASA Technical Reports Server (NTRS)

deGroh, Henry C., III; Miller, Sharon K. R.; Smith, Ian M.; Daniels, Christopher C.; Steinetz, Bruce M

2008-01-01

Silicone rubber seals are being considered for a number of interfaces on NASA's Crew Exploration Vehicle (CEV). Some of these joints include the docking system, hatches, and heat shield-to-back shell interface. A large diameter molded silicone seal is being developed for the Low Impact Docking System (LIDS) that forms an effective seal between the CEV and International Space Station (ISS) and other future Constellation Program spacecraft. Seals between the heat shield and back shell prevent high temperature reentry gases from leaking into the interface. Silicone rubber seals being considered for these locations have inherent adhesive tendencies that would result in excessive forces required to separate the joints if left unchecked. This paper summarizes adhesion assessments for both as-received and adhesion-mitigated seals for the docking system and the heat shield interface location. Three silicone elastomers were examined: Parker Hannifin S0899-50 and S0383-70 compounds, and Esterline ELA-SA-401 compound. For the docking system application various levels of exposure to atomic oxygen (AO) were evaluated. Moderate AO treatments did not lower the adhesive properties of S0899-50 sufficiently. However, AO pretreatments of approximately 10(exp 20) atoms/sq cm did lower the adhesion of S0383-70 and ELA-SA-401 to acceptable levels. For the heat shield-to-back shell interface application, a fabric covering was also considered. Molding Nomex fabric into the heat shield pressure seal appreciably reduced seal adhesion for the heat shield-to-back shell interface application.

Current Situation for Management of Disused Sealed Radioactive Sources in Japan - 13025

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kusama, Keiji; Miyamoto, Yoichi

2013-07-01

As for the Sealed Radioactive Source currently used in Japan, many of them are imported from overseas. The U.S., Canada, Germany, the Netherlands, Belgium and Czech Republic are the main exporting States. Many of disused sealed radioactive sources are being returned to exporting States. The sealed radioactive sources which cannot be returned to exporting States are appropriately kept in the domestic storage facility. So, there are not main problem on the long term management of disused sealed radioactive sources in Japan. However, there are some difficulties on repatriate. One is reservation of a means of transport. The sea mail whichmore » conveys radioactive sources owing to reduction of movement of international cargo is decreasing in number. And there is a denial of shipment. Other one is that the manufacturer has already resigned from the work and cannot return disused sealed radioactive sources, or a manufacturer cannot specify and disused sources cannot be returned. The disused sealed radioactive source which cannot be repatriated is a little in term of radioactivity. As for the establishment of national measure of final disposal facility for disused sealed radioactive sources, in Japan, it is not yet installed with difficulty. Since there are many countries for which installation of a final disposal facility for disused sealed radioactive sources is difficult, the source manufacture country should respond positively to return the source which was manufactured and sold in the past. (authors)« less

One-sided truncated sequential t-test: application to natural resource sampling

Treesearch

Gary W. Fowler; William G. O' Regan

1974-01-01

A new procedure for constructing one-sided truncated sequential t-tests and its application to natural resource sampling are described. Monte Carlo procedures were used to develop a series of one-sided truncated sequential t-tests and the associated approximations to the operating characteristic and average sample number functions. Different truncation points and...

Trial Sequential Analysis in systematic reviews with meta-analysis.

PubMed

Wetterslev, Jørn; Jakobsen, Janus Christian; Gluud, Christian

2017-03-06

Most meta-analyses in systematic reviews, including Cochrane ones, do not have sufficient statistical power to detect or refute even large intervention effects. This is why a meta-analysis ought to be regarded as an interim analysis on its way towards a required information size. The results of the meta-analyses should relate the total number of randomised participants to the estimated required meta-analytic information size accounting for statistical diversity. When the number of participants and the corresponding number of trials in a meta-analysis are insufficient, the use of the traditional 95% confidence interval or the 5% statistical significance threshold will lead to too many false positive conclusions (type I errors) and too many false negative conclusions (type II errors). We developed a methodology for interpreting meta-analysis results, using generally accepted, valid evidence on how to adjust thresholds for significance in randomised clinical trials when the required sample size has not been reached. The Lan-DeMets trial sequential monitoring boundaries in Trial Sequential Analysis offer adjusted confidence intervals and restricted thresholds for statistical significance when the diversity-adjusted required information size and the corresponding number of required trials for the meta-analysis have not been reached. Trial Sequential Analysis provides a frequentistic approach to control both type I and type II errors. We define the required information size and the corresponding number of required trials in a meta-analysis and the diversity (D 2 ) measure of heterogeneity. We explain the reasons for using Trial Sequential Analysis of meta-analysis when the actual information size fails to reach the required information size. We present examples drawn from traditional meta-analyses using unadjusted naïve 95% confidence intervals and 5% thresholds for statistical significance. Spurious conclusions in systematic reviews with traditional meta-analyses can be reduced using Trial Sequential Analysis. Several empirical studies have demonstrated that the Trial Sequential Analysis provides better control of type I errors and of type II errors than the traditional naïve meta-analysis. Trial Sequential Analysis represents analysis of meta-analytic data, with transparent assumptions, and better control of type I and type II errors than the traditional meta-analysis using naïve unadjusted confidence intervals.

Architecture, Design and Implementation of RC64, a Many-Core High-Performance DSP for Space Applications

NASA Astrophysics Data System (ADS)

Ginosar, Ran; Aviely, Peleg; Liran, Tuvia; Alon, Dov; Dobkin, Reuven; Goldberg, Michael

2013-08-01

RC64, a novel 64-core many-core signal processing chip targets DSP performance of 12.8 GIPS, 100 GOPS and 12.8 single precision GFLOS while dissipating only 3 Watts. RC64 employs advanced DSP cores, a multi-bank shared memory and a hardware scheduler, supports DDR2 memory and communicates over five proprietary 6.4 Gbps channels. The programming model employs sequential fine-grain tasks and a separate task map to define task dependencies. RC64 is implemented as a 200 MHz ASIC on Tower 130nm CMOS technology, assembled in hermetically sealed ceramic QFP package and qualified to the highest space standards.

Device for rapid quantification of human carotid baroreceptor-cardiac reflex responses

NASA Technical Reports Server (NTRS)

Sprenkle, J. M.; Eckberg, D. L.; Goble, R. L.; Schelhorn, J. J.; Halliday, H. C.

1986-01-01

A new device has been designed, constructed, and evaluated to characterize the human carotid baroreceptor-cardiac reflex response relation rapidly. This system was designed for study of reflex responses of astronauts before, during, and after space travel. The system comprises a new tightly sealing silicon rubber neck chamber, a stepping motor-driven electrodeposited nickel bellows pressure system, capable of delivering sequential R-wave-triggered neck chamber pressure changes between +40 and -65 mmHg, and a microprocessor-based electronics system for control of pressure steps and analysis and display of responses. This new system provokes classic sigmoid baroreceptor-cardiac reflex responses with threshold, linear, and saturation ranges in most human volunteers during one held expiration.

REACTOR COOLANT TUBE SEAL

DOEpatents

Morris, W.J.

1958-12-01

A plle-flattenlng control element and a fluid seal therefore to permit movement of the element into a liquld contnining region of a neutronlc reactor are described. The device consists of flattened, thin-walled aluminum tubing contalnlng a uniform mixture of thermal neutron absorbing material, and a number of soft rubber closures for the process tubes, having silts capable of passing the flattened elements therethrough, but effectively sealing the process tubes against fluld leaknge by compression of the rubber. The flattened tubing is sufficiently flexible to enable it to conform to the configuratlon of the annular spacing surrounding the fuel elements ln the process tubes.

An experimental study of dynamic characteristics of labyrinth seal

NASA Technical Reports Server (NTRS)

Iwatsubo, Takuzo; Fukumoto, Koji; Mochida, Hideyuki

1994-01-01

The fluid force due to labyrinth seal sometimes makes the turbomachineries unstable under higher rotating speed, higher pressure and higher power. Therefore, it is important to predict the magnitude and the direction of the fluid force and to evaluate the stability of the rotor system in design process. This paper shows the experimental results of the fluid force induced by a straight labyrinth seal and the rotordynamic coefficients calculated from the fluid force. Influences of the number of fins under the rotating speed, whirling speed, inlet pressure, and inlet tangential velocity are mainly investigated on a stability of the rotor system. The results show that increase of the number of fins makes the fluid force small and the rotor system stable, an increase of inlet pressure makes the fluid forces large and an increase of inlet tangential velocity makes the rotor system unstable.

A generic motif discovery algorithm for sequential data.

PubMed

Jensen, Kyle L; Styczynski, Mark P; Rigoutsos, Isidore; Stephanopoulos, Gregory N

2006-01-01

Motif discovery in sequential data is a problem of great interest and with many applications. However, previous methods have been unable to combine exhaustive search with complex motif representations and are each typically only applicable to a certain class of problems. Here we present a generic motif discovery algorithm (Gemoda) for sequential data. Gemoda can be applied to any dataset with a sequential character, including both categorical and real-valued data. As we show, Gemoda deterministically discovers motifs that are maximal in composition and length. As well, the algorithm allows any choice of similarity metric for finding motifs. Finally, Gemoda's output motifs are representation-agnostic: they can be represented using regular expressions, position weight matrices or any number of other models for any type of sequential data. We demonstrate a number of applications of the algorithm, including the discovery of motifs in amino acids sequences, a new solution to the (l,d)-motif problem in DNA sequences and the discovery of conserved protein substructures. Gemoda is freely available at http://web.mit.edu/bamel/gemoda

Method for polymer synthesis in a reaction well

DOEpatents

Brennan, Thomas M.

1998-01-01

A method of synthesis for building a polymer chain, oligonucleotides in particular, by sequentially adding monomer units to at least one solid support for growing and immobilizing a polymer chain thereon in a liquid reagent solution. The method includes the step of: A) depositing a liquid reagent in a reaction well (26) in contact with at least one solid support and at least one monomer unit of the polymer chain affixed to the solid support. The well (26) includes at least one orifice (74) extending into the well (26), and is of a size and dimension to form a capillary liquid seal to retain the reagent solution in the well (26) to enable polymer chain growth on the solid support. The method further includes the step of B) expelling the reagent solution from the well (26), while retaining the polymer chain therein. This is accomplished by applying a first gas pressure to the reaction well such that a pressure differential between the first gas pressure and a second gas pressure exerted on an exit (80) of the orifice (74) exceeds a predetermined amount sufficient to overcome the capillary liquid seal and expel the reagent solution from the well (26) through the orifice exit (80).

Method for polymer synthesis in a reaction well

DOEpatents

Brennan, T.M.

1998-09-29

A method of synthesis is described for building a polymer chain, oligonucleotides in particular, by sequentially adding monomer units to at least one solid support for growing and immobilizing a polymer chain thereon in a liquid reagent solution. The method includes the step of: (A) depositing a liquid reagent in a reaction well in contact with at least one solid support and at least one monomer unit of the polymer chain affixed to the solid support. The well includes at least one orifice extending into the well, and is of a size and dimension to form a capillary liquid seal to retain the reagent solution in the well to enable polymer chain growth on the solid support. The method further includes the step of (B) expelling the reagent solution from the well, while retaining the polymer chain therein. This is accomplished by applying a first gas pressure to the reaction well such that a pressure differential between the first gas pressure and a second gas pressure exerted on an exit of the orifice exceeds a predetermined amount sufficient to overcome the capillary liquid seal and expel the reagent solution from the well through the orifice exit. 9 figs.

Mapping of Technological Opportunities-Labyrinth Seal Example

NASA Technical Reports Server (NTRS)

Clarke, Dana W., Sr.

2006-01-01

All technological systems evolve based on evolutionary sequences that have repeated throughout history and can be abstracted from the history of technology and patents. These evolutionary sequences represent objective patterns and provide considerable insights that can be used to proactively model future seal concepts. This presentation provides an overview of how to map seal technology into the future using a labyrinth seal example. The mapping process delivers functional descriptions of sequential changes in market/consumer demand, from today s current paradigm to the next major paradigm shift. The future paradigm is developed according to a simple formula: the future paradigm is free of all flaws associated with the current paradigm; it is as far into the future as we can see. Although revolutionary, the vision of the future paradigm is typically not immediately or completely realizable nor is it normally seen as practical. There are several reasons that prevent immediate and complete practical application, such as: 1) Some of the required technological or business resources and knowledge not being available; 2) Availability of other technological or business resources are limited; and/or 3) Some necessary knowledge has not been completely developed. These factors tend to drive the Total Cost of Ownership or Utilization out of an acceptable range and revealing the reasons for the high Total Cost of Ownership or Utilization which provides a clear understanding of research opportunities essential for future developments and defines the current limits of the immediately achievable improvements. The typical roots of high Total Cost of Ownership or Utilization lie in the limited availability or even the absence of essential resources and knowledge necessary for its realization. In order to overcome this obstacle, step-by-step modification of the current paradigm is pursued to evolve from the current situation toward the ideal future, i.e., evolution rather than revolution. A key point is that evolutionary stages are mapped to show step-by-step evolution from the current paradigm to the next major paradigm.

The vocal monotony of monogamy

NASA Astrophysics Data System (ADS)

Thomas, Jeanette

2003-04-01

There are four phocids in waters around Antarctica: Weddell, leopard, crabeater, and Ross seals. These four species provide a unique opportunity to examine underwater vocal behavior in species sharing the same ecosystem. Some species live in pack ice, others in factice, but all are restricted to the Antarctic or sub-Antarctic islands. All breed and produce vocalizations under water. Social systems range from polygyny in large breeding colonies, to serial monogamy, to solitary species. The type of mating system influences the number of underwater vocalizations in the repertoire, with monogamous seals producing only a single call, polygynous species producing up to 35 calls, and solitary species an intermediate number of about 10 calls. Breeding occurs during the austral spring and each species carves-out an acoustic niche for communicating, with species using different frequency ranges, temporal patterns, and amplitude changes to convey their species-specific calls and presumably reduce acoustic competition. Some species exhibit geographic variations in their vocalizations around the continent, which may reflect discrete breeding populations. Some seals become silent during a vulnerable time of predation by killer whales, perhaps to avoid detection. Overall, vocalizations of these seals exhibit adaptive characteristics that reflect the co-evolution among species in the same ecosystem.

Laser stapedotomy: a comparative study of prostheses and seals.

PubMed

Perkins, R; Curto, F S

1992-12-01

During the past 13 years, a number of prostheses of differing design and tissue seals have been used in laser stapedotomy for otosclerosis. This study compares the results of three different configurations of prostheses and tissue seals in a series of 53 patients. In 19, a platinum wire Teflon piston was placed in the laser stapedotomy fenestra and crimped on the long process of the incus; autologous venous blood was infiltrated into the oval window niche as a sealing mechanism. In 8 patients, a stainless steel bucket-handle-type prosthesis was used with a blood tissue seal. In 26 patients, a segment of autogenous vein was clad onto the bucket-handle-type prosthesis and placed into the laser fenestra. Two tissue seals (blood and vein) were also compared. The results were compared with regard to several audiometric parameters. It would appear that the bucket handle/vein configuration improves air-bone gap closure in the low- and mid-frequency speech range and also shows an advantage for air-bone gap closure to 10 dB or less compared to the other configurations in this study. Mean postoperative gaps were significantly less for vein compared to the blood tissue seal. Physiologic and surgical implications are discussed, and the vein-clad technique is illustrated.

Type I and Type II Error Rates and Overall Accuracy of the Revised Parallel Analysis Method for Determining the Number of Factors

ERIC Educational Resources Information Center

Green, Samuel B.; Thompson, Marilyn S.; Levy, Roy; Lo, Wen-Juo

2015-01-01

Traditional parallel analysis (T-PA) estimates the number of factors by sequentially comparing sample eigenvalues with eigenvalues for randomly generated data. Revised parallel analysis (R-PA) sequentially compares the "k"th eigenvalue for sample data to the "k"th eigenvalue for generated data sets, conditioned on"k"-…

Material Properties of Three Candidate Elastomers for Space Seals Applications

NASA Technical Reports Server (NTRS)

Bastrzyk, Marta B.; Daniels, Christopher C.; Oswald, Jay J.; Dunlap, Patrick H., Jr.; Steinetz, Bruce M.

2010-01-01

A next-generation docking system is being developed by the National Aeronautics and Space Administration (NASA) to support Constellation Space Exploration Missions to low Earth orbit (LEO), to the Moon, and to Mars. A number of investigations were carried out to quantify the properties of candidate elastomer materials for use in the main interface seal of the Low Impact Docking System (LIDS). This seal forms the gas pressure seal between two mating spacecraft. Three candidate silicone elastomer compounds were examined: Esterline ELA-SA-401, Parker Hannifin S0383-70, and Parker Hannifin S0899-50. All three materials were characterized as low-outgassing compounds, per ASTM E595, so as to minimize the contamination of optical and solar array systems. Important seal properties such as outgas levels, durometer, tensile strength, elongation to failure, glass transition temperature, permeability, compression set, Yeoh strain energy coefficients, coefficients of friction, coefficients of thermal expansion, thermal conductivity and diffusivity were measured and are reported herein.

Linking mesopelagic prey abundance and distribution to the foraging behavior of a deep-diving predator, the northern elephant seal

NASA Astrophysics Data System (ADS)

Saijo, Daisuke; Mitani, Yoko; Abe, Takuzo; Sasaki, Hiroko; Goetsch, Chandra; Costa, Daniel P.; Miyashita, Kazushi

2017-06-01

The Transition Zone in the eastern North Pacific is important foraging habitat for many marine predators. Further, the mesopelagic depths (200-1000 m) host an abundant prey resource known as the deep scattering layer that supports deep diving predators, such as northern elephant seals, beaked whales, and sperm whales. Female northern elephant seals (Mirounga angustirostris) undertake biannual foraging migrations to this region where they feed on mesopelagic fish and squid; however, in situ measurements of prey distribution and abundance, as well as the subsurface oceanographic features in the mesopelagic Transition Zone are limited. While concurrently tracking female elephant seals during their post-molt migration, we conducted a ship-based oceanographic and hydroacoustic survey and used mesopelagic mid-water trawls to sample the deep scattering layer. We found that the abundance of mesopelagic fish at 400-600 m depth zone was the highest in the 43 °N zone, the primary foraging area of female seals. We identified twenty-nine families of fishes from the mid-water trawls, with energy-rich myctophid fishes dominating by species number, individual number, and wet weight. Biomass of mesopelagic fishes is positively correlated to annual net primary productivity; however, at the temporal and spatial scale of our study, we found no relationship between satellite derived surface primary production and prey density. Instead, we found that the subsurface chlorophyll maximum correlated with the primary elephant seal foraging regions, indicating a stronger linkage between mesopelagic ecosystem dynamics and subsurface features rather than the surface features measured with satellites. Our study not only provides insights on prey distribution in a little-studied deep ocean ecosystem, but shows that northern elephant seals are targeting the dense, species-diverse mesopelagic ecosystem at the gyre-gyre boundary that was previously inferred from their diving behavior.

Suberin: the biopolyester at the frontier of plants

NASA Astrophysics Data System (ADS)

Graça, José

2015-10-01

Suberin is a lipophilic macromolecule found in specialized plant cell walls, wherever insulation or protection towards the surroundings is needed. Suberized cells form the periderm, the tissue that envelops secondary stems as part of the bark, and develop as the sealing tissue after wounding or leaf abscission. Suberin is a complex polyester built from poly-functional long-chain fatty acids (suberin acids) and glycerol. The suberin acids composition of a number of plant tissues and species is now established, but how the polyester macromolecule is assembled within the suberized cell walls is not known. In the last years contributions from several areas have however significantly enriched our understanding of suberin. The primary structure of the polyester, i.e. how the suberin acids and glycerol are sequentially linked was revealed, together with the stereochemistry of the mid-chain functional groups some suberin acids have; solid-state NMR studies showed the presence of methylene chains spatially separated and with different molecular mobility; biophysical studies showed the membrane behaviour of suberin acids derivatives, allowing new insights on structure-properties relationships; and a number of candidate genes were conclusively related to suberin biosynthesis. The comprehension of suberin as a macromolecule will be essential to understand its vital protective roles in plants and how they will deal with eventual environmental changes. Suberin is also expected to be a source for high-performing bio-based chemicals, taking advantage of the structural uniqueness of their constituent suberin acids.

48 CFR 252.101 - Using part 252.

Code of Federal Regulations, 2010 CFR

2010-10-01

... FAR. (ii)(B) DFARS provisions or clauses use a four digit sequential number in the 7000 series, e.g., -7000, -7001, -7002. Department or agency supplemental provisions or clauses use four digit sequential...

Exploiting an automated microfluidic hydrodynamic sequential injection system for determination of phosphate.

PubMed

Khongpet, Wanpen; Pencharee, Somkid; Puangpila, Chanida; Kradtap Hartwell, Supaporn; Lapanantnoppakhun, Somchai; Jakmunee, Jaroon

2018-01-15

A microfluidic hydrodynamic sequential injection (μHSI) spectrophotometric system was designed and fabricated. The system was built by laser engraving a manifold pattern on an acrylic block and sealing with another flat acrylic plate to form a microfluidic channel platform. The platform was incorporated with small solenoid valves to obtain a portable setup for programmable control of the liquid flow into the channel according to the HSI principle. The system was demonstrated for the determination of phosphate using a molybdenum blue method. An ascorbic acid, standard or sample, and acidic molybdate solutions were sequentially aspirated to fill the channel forming a stack zone before flowing to the detector. Under the optimum condition, a linear calibration graph in the range of 0.1-6mg P L -1 was obtained. The detection limit was 0.1mgL -1 . The system is compact (5.0mm thick, 80mm wide × 140mm long), durable, portable, cost-effective, and consumes little amount of chemicals (83μL each of molybdate and ascorbic acid, 133μL of the sample solution and 1.7mL of water carrier/run). It was applied for the determination of phosphate content in extracted soil samples. The percent recoveries of the analysis were obtained in the range of 91.2-107.3. The results obtained agreed well with those of the batch spectrophotometric method. Copyright © 2017 Elsevier B.V. All rights reserved.

40 CFR 53.34 - Test procedure for methods for PM10 and Class I methods for PM2.5.

Code of Federal Regulations, 2010 CFR

2010-07-01

... simultaneous PM10 or PM2.5 measurements as necessary (see table C-4 of this subpart), each set consisting of...) in appendix A to this subpart). (f) Sequential samplers. For sequential samplers, the sampler shall be configured for the maximum number of sequential samples and shall be set for automatic collection...

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

PubMed

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.

Effects of geometric variables on rub characteristics of Ti-6Al-4V

NASA Technical Reports Server (NTRS)

Bill, R. C.; Wolak, J.; Wisander, D. W.

1981-01-01

Experiments simulating rub interactions between Ti-6Al-4V blade tips and various seal materials were conducted. The number of blade tips and the blade tip geometry were varied to determine their effects on rub forces and on wear phenomena. Contact was found to be quite unsteady for all blade tip geometries except for those incorporating deliberately rounded blade tips. The unsteady contact was characterized by long periods of rubbing contact and increasing blade tip that terminated in sudden rapid metal removal, sometimes accompanied by tearing and disruption of porous seal material under the rub surface. A model describing the blade tip loading is proposed and is based on the propagation of an elastic stress wave through the seal material as the seal material is dynamically compressed by the blade tip leading edge.

Measurements of Pressure Distributions and Force Coefficients in a Squeeze Film Damper. Part 2: Partially Sealed Configuration

NASA Technical Reports Server (NTRS)

Jung, S. Y.; Sanandres, Luis A.; Vance, J. M.

1991-01-01

Experimental results from a partially sealed squeeze film damper (SFD) test rig, executing a circular centered orbit are presented and discussed. A serrated piston ring is installed at the damper exit. This device involves a new sealing concept which produces high damping values while allowing for oil flow to cool the damper. In the partially sealed damper, large cavitation regions are observed in the pressure fields at orbit radii epsilon equals 0.5 and epsilon equals 0.8. The cavitated pressure distributions and the corresponding force coefficients are compared with a cavitated bearing solution. The experimental results show the significance of fluid inertia and vapor cavitation in the operation of squeeze film dampers. Squeeze film Reynolds numbers tested reach up to Re equals 50, spanning the range of contemporary applications.

Experimental Investigations of Exciting Forces Caused by Flow in Labyrinth Seals

NASA Technical Reports Server (NTRS)

Thieleke, G.; Stetter, H.

1991-01-01

The interaction of the flow through the labyrinth seals with the shaft of the rotor can have an effect on the stability of turbomachines. Thus, the excited forces, so-called cross forces or nonconservative forces, arise, which act perpendicular to the rotor eccentricity. This effect is caused by an unsymmetrical pressure distribution within the labyrinth cavities. Experimental studies were carried out for different types of labyrinth geometries: two staggered labyrinths with teeth on the stator and grooved rotor as well as a full and a convergent stepped labyrinth. These labyrinths can be found on the tip shrouding of bladings in steam or gas turbines. The following parameters were varied in the test facility: geometry of the labyrinth seals (number of cavities, inlet region), shaft rotation, pressure difference on the seal, entry swirl and eccentricity of the rotor. The results are presented for stiffness coefficients of the labyrinth seals, leakage flow and circumferential flow in each cavity which was measured with special probes. Generally, the inlet swirl has the greatest influence on the coefficients of the seals. The experimental results were compared with theoretical results and were in good agreement.

Metagenomic Survey of Viral Diversity Obtained from Feces of Subantarctic and South American Fur Seals

PubMed Central

Kluge, Mariana; Campos, Fabrício Souza; Tavares, Maurício; de Amorim, Derek Blaese; Valdez, Fernanda Pedone; Giongo, Adriana; Roehe, Paulo Michel; Franco, Ana Claudia

2016-01-01

The Brazilian South coast seasonally hosts numerous marine species, observed particularly during winter months. Some animals, including fur seals, are found dead or debilitated along the shore and may harbor potential pathogens within their microbiota. In the present study, a metagenomic approach was performed to evaluate the viral diversity in feces of fur seals found deceased along the coast of the state of Rio Grande do Sul. The fecal virome of two fur seal species was characterized: the South American fur seal (Arctocephalus australis) and the Subantarctic fur seal (Arctocephalus tropicalis). Fecal samples from 10 specimens (A. australis, n = 5; A. tropicalis, n = 5) were collected and viral particles were purified, extracted and amplified with a random PCR. The products were sequenced through Ion Torrent and Illumina platforms and assembled reads were submitted to BLASTx searches. Both viromes were dominated by bacteriophages and included a number of potentially novel virus genomes. Sequences of picobirnaviruses, picornaviruses and a hepevirus-like were identified in A. australis. A rotavirus related to group C, a novel member of the Sakobuvirus and a sapovirus very similar to California sea lion sapovirus 1 were found in A. tropicalis. Additionally, sequences of members of the Anelloviridae and Parvoviridae families were detected in both fur seal species. This is the first metagenomic study to screen the fecal virome of fur seals, contributing to a better understanding of the complexity of the viral community present in the intestinal microbiota of these animals. PMID:26986573

Variability of Hormonal Stress Markers and Stress Responses in a Large Cross-Sectional Sample of Elephant Seals

DTIC Science & Technology

2011-09-30

massey.ac.nz Award Number: N000141110434 LONG-TERM GOALS Physiological indicators of stress in wild marine mammals, the interrelationships between...hormones (GC), aldosterone (A), thyroid hormones (TH), and catecholamines within a free-ranging northern elephant seal population and its...additional individuals per year). Serum samples will be processed for ACTH, cortisol, aldosterone , catecholamines (epinephrine, norepinephrine), and

Something's fishy. [Marine epidemics may signal environmental threats from pollutants such as PCBs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raloff, J.

1994-07-02

Marine epidemics may signal environmental threats to the immune system of marine animals such as seals, dolphins and turtles. A number of studies are discussed in this article, with particular emphasis on an ongoing study which makes the connection between marine pollution and the decrease in immune system functioning in harbor seals. The effects on the whole marine ecosystem are discussed.

Monte Carlo Simulation of Sudden Death Bearing Testing

NASA Technical Reports Server (NTRS)

Vlcek, Brian L.; Hendricks, Robert C.; Zaretsky, Erwin V.

2003-01-01

Monte Carlo simulations combined with sudden death testing were used to compare resultant bearing lives to the calculated hearing life and the cumulative test time and calendar time relative to sequential and censored sequential testing. A total of 30 960 virtual 50-mm bore deep-groove ball bearings were evaluated in 33 different sudden death test configurations comprising 36, 72, and 144 bearings each. Variations in both life and Weibull slope were a function of the number of bearings failed independent of the test method used and not the total number of bearings tested. Variation in L10 life as a function of number of bearings failed were similar to variations in lift obtained from sequentially failed real bearings and from Monte Carlo (virtual) testing of entire populations. Reductions up to 40 percent in bearing test time and calendar time can be achieved by testing to failure or the L(sub 50) life and terminating all testing when the last of the predetermined bearing failures has occurred. Sudden death testing is not a more efficient method to reduce bearing test time or calendar time when compared to censored sequential testing.

Boolean Minimization and Algebraic Factorization Procedures for Fully Testable Sequential Machines

DTIC Science & Technology

1989-09-01

Boolean Minimization and Algebraic Factorization Procedures for Fully Testable Sequential Machines Srinivas Devadas and Kurt Keutzer F ( Abstract In this...Projects Agency under contract number N00014-87-K-0825. Author Information Devadas : Department of Electrical Engineering and Computer Science, Room 36...MA 02139; (617) 253-0292. 0 * Boolean Minimization and Algebraic Factorization Procedures for Fully Testable Sequential Machines Siivas Devadas

Constrained optimization of sequentially generated entangled multiqubit states

NASA Astrophysics Data System (ADS)

Saberi, Hamed; Weichselbaum, Andreas; Lamata, Lucas; Pérez-García, David; von Delft, Jan; Solano, Enrique

2009-08-01

We demonstrate how the matrix-product state formalism provides a flexible structure to solve the constrained optimization problem associated with the sequential generation of entangled multiqubit states under experimental restrictions. We consider a realistic scenario in which an ancillary system with a limited number of levels performs restricted sequential interactions with qubits in a row. The proposed method relies on a suitable local optimization procedure, yielding an efficient recipe for the realistic and approximate sequential generation of any entangled multiqubit state. We give paradigmatic examples that may be of interest for theoretical and experimental developments.

Evaluating the use of stable isotope analysis to infer the feeding ecology of a growing US gray seal (Halichoerus grypus) population.

PubMed

Lerner, Jacob E; Ono, Kathryn; Hernandez, Keith M; Runstadler, Jonathan A; Puryear, Wendy B; Polito, Michael J

2018-01-01

Gray seals (Halichoerus grypus) have been rapidly recolonizing the Northeast US coast, eliciting concern from the fishing industry. However, the ecological effect of this recovery is still unknown and as such, research is needed to better understand how the diet composition of gray seals in US waters will contribute to the ecological impact. While previous research on seal diets has focused on the analysis of hard prey remains, stable isotope analysis presents an alternative method that can be used to describe marine mammal diets when direct observation is impossible. To address this issue, we used stable isotope analysis of gray seal pup vibrissae and lanugo from Monomoy Island, Cape Cod, MA during the 2015/2016 winter breeding season to estimate adult female diet composition during pregnancy. Stable isotope mixing models (SIMM) suggested adult female gray seals were consuming greater amounts of cephalopod prey and less sand lance than previously indicated from analysis of hard prey remains. However, using SIMMs to estimate the diet composition of gray seals remains difficult due to the large number of isotopically similar prey species and uncertainty in tissue-specific, stable isotope trophic enrichment factors. Even so, by combining prey sources into ecologically informative groups and integrating prior information into SIMMs it is possible to obtain additional insights into the diet of this generalist predator.

Vortex Shedding in the Wake Induced by a Real Elephant Seal Whisker

NASA Astrophysics Data System (ADS)

Turk, Jodi; Omilion, Alexis; Zhang, Wei; Kim, Jeong-Jae; Kim, Jeong-Ju; Choi, Woo-Rak; Lee, Sang-Joon

2017-11-01

Biomimicry has been adopted to create innovative solutions in a vast range of applications. One such application is the design of seal-whisker-inspired flow sensors for autonomous underwater vehicles (AUVs). In dark, cramped, and unstable terrain AUVs are not able to maneuver using visual and sonar-based navigation. Hence, it is critical to use underwater flow sensors to accurately detect minute disturbances in the surroundings. Certain seal whiskers exhibit a unique undulating three-dimensional morphology that can reduce vortex induced vibrations (VIVs) if the major axis of the whisker cross-section is aligned to the inflow. This allows the seal to precisely track prey fish upstream using solely their whiskers. The current study aims to understand the effect of a real seal whisker's morphology on the vortex shedding behavior. Despite extensive studies of wake induced by scaled whisker-like models, the vortex shedding in the wake of a real seal whisker is not well understood. A series of experiments are conducted with a high-speed Particle Imaging Velocimetry (PIV) system in a water channel to examine the vortex shedding downstream from a smooth whisker and an undulating whisker at a Reynolds number of a few hundred. Results of the vortex shedding induced by real seal whiskers can provide insights on developing high-sensitivity underwater flow sensors for AUVs and other whisker-inspired structures.

Differential-Game Examination of Optimal Time-Sequential Fire-Support Strategies

DTIC Science & Technology

1976-09-01

77 004033 NPS-55Tw76091 NAVAL POSTGRADUATE SCHOOL 4Monterey, California i ’ DIFFERENTIAL- GAME EXAMINATION OF OPTIMAL TIME-SEQUENTIAL FIRE...CATALOG NUMBER NPS-55Tw76091 4. TITLE (and Subtitle) S. TYPE OF REPDRT & PERIOD COVERED Differential- Game Examination of Optimal Tir Technical Report...NOTES 19. KEY WORDS (Continue on reverse side If necessary and identify by block number) Differential Games Lanchester Theory of Combat Military Tactics

Infrared laser sealing of porcine vascular tissues using a 1,470 nm diode laser: Preliminary in vivo studies.

PubMed

Cilip, Christopher M; Kerr, Duane; Latimer, Cassandra A; Rosenbury, Sarah B; Giglio, Nicholas C; Hutchens, Thomas C; Nau, William H; Fried, Nathaniel M

2017-04-01

Infrared (IR) lasers are being explored as an alternative to radiofrequency (RF) and ultrasonic (US) devices for rapid hemostasis with minimal collateral zones of thermal damage and tissue necrosis. Previously, a 1,470 nm IR laser sealed and cut ex vivo porcine renal arteries of 1-8 mm diameter in 2 seconds, yielding burst pressures greater than 1,200 mmHg and thermal coagulation zones less than 3 mm. This preliminary study describes in vivo testing of a handheld laser probe in a porcine model. A handheld prototype with vessel/tissue clasping mechanism was tested on 73 blood vessels less than 6 mm diameter using 1,470 nm laser power of 35 W for 1-5 seconds. Device power settings, irradiation time, tissue type, vessel diameter, and histology sample number were recorded for each procedure. The probe was evaluated for hemostasis after sealing isolated and bundled arteriole/venous (A/V) vasculature of porcine abdomen and hind leg. Sealed vessel samples were collected for histological analysis of lateral thermal damage. Hemostasis was achieved in 57 of 73 seals (78%). The probe consistently sealed vasculature in small bowel mesentery, mesometrium, and gastrosplenic and epiploic regions. Seal performance was less consistent on hind leg vasculature including saphenous arteries/bundles and femoral and iliac arteries. Collagen denaturation averaged 1.6 ± 0.9 mm in eight samples excised for histologic examination. A handheld laser probe sealed porcine vessels, in vivo. Further probe development and laser parameter optimization is necessary before infrared lasers may be evaluated as an alternative to RF and US vessel sealing devices. Lasers Surg. Med. 49:366-371, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

RC64, a Rad-Hard Many-Core High- Performance DSP for Space Applications

NASA Astrophysics Data System (ADS)

Ginosar, Ran; Aviely, Peleg; Gellis, Hagay; Liran, Tuvia; Israeli, Tsvika; Nesher, Roy; Lange, Fredy; Dobkin, Reuven; Meirov, Henri; Reznik, Dror

2015-09-01

RC64, a novel rad-hard 64-core signal processing chip targets DSP performance of 75 GMACs (16bit), 150 GOPS and 38 single precision GFLOPS while dissipating less than 10 Watts. RC64 integrates advanced DSP cores with a multi-bank shared memory and a hardware scheduler, also supporting DDR2/3 memory and twelve 3.125 Gbps full duplex high speed serial links using SpaceFibre and other protocols. The programming model employs sequential fine-grain tasks and a separate task map to define task dependencies. RC64 is implemented as a 300 MHz integrated circuit on a 65nm CMOS technology, assembled in hermetically sealed ceramic CCGA624 package and qualified to the highest space standards.

RC64, a Rad-Hard Many-Core High-Performance DSP for Space Applications

NASA Astrophysics Data System (ADS)

Ginosar, Ran; Aviely, Peleg; Liran, Tuvia; Alon, Dov; Mandler, Alberto; Lange, Fredy; Dobkin, Reuven; Goldberg, Miki

2014-08-01

RC64, a novel rad-hard 64-core signal processing chip targets DSP performance of 75 GMACs (16bit), 150 GOPS and 20 single precision GFLOPS while dissipating less than 10 Watts. RC64 integrates advanced DSP cores with a multi-bank shared memory and a hardware scheduler, also supporting DDR2/3 memory and twelve 2.5 Gbps full duplex high speed serial links using SpaceFibre and other protocols. The programming model employs sequential fine-grain tasks and a separate task map to define task dependencies. RC64 is implemented as a 300 MHz integrated circuit on a 65nm CMOS technology, assembled in hermetically sealed ceramic CCGA624 package and qualified to the highest space standards.

Variability of Hormonal Stress Markers and Stress Responses in a Large Cross-Sectional Sample of Elephant Seals

DTIC Science & Technology

2013-09-30

cortisol and aldosterone impacted glucose, lactate, NEFA , BUN and electrolyte levels. These data provide novel information on the physiological and...massey.ac.nz Award Number: N000141110434 LONG-TERM GOALS Physiological indicators of stress in wild marine mammals, the interrelationships...glucocorticoid hormones (GC), aldosterone (A), thyroid hormones (TH), and catecholamines within a free-ranging northern elephant seal population and its

Variability of Hormonal Stress Markers and Stress Responses in a Large Cross-Sectional Sample of Elephant Seals

DTIC Science & Technology

2014-09-30

cortisol and aldosterone impacted glucose, lactate, NEFA , BUN and electrolyte levels. These data provide novel information on the physiological and...massey.ac.nz Award Number: N000141110434 LONG-TERM GOALS Physiological indicators of stress in wild marine mammals, the interrelationships between...hormones (GC), aldosterone (A), thyroid hormones (TH), and catecholamines within a free-ranging northern elephant seal population and its dependence

The foraging benefits of being fat in a highly migratory marine mammal

PubMed Central

Adachi, Taiki; Maresh, Jennifer L.; Robinson, Patrick W.; Peterson, Sarah H.; Costa, Daniel P.; Naito, Yasuhiko; Watanabe, Yuuki Y.; Takahashi, Akinori

2014-01-01

Foraging theory predicts that breath-hold divers adjust the time spent foraging at depth relative to the energetic cost of swimming, which varies with buoyancy (body density). However, the buoyancy of diving animals varies as a function of their body condition, and the effects of these changes on swimming costs and foraging behaviour have been poorly examined. A novel animal-borne accelerometer was developed that recorded the number of flipper strokes, which allowed us to monitor the number of strokes per metre swam (hereafter, referred to as strokes-per-metre) by female northern elephant seals over their months-long, oceanic foraging migrations. As negatively buoyant seals increased their fat stores and buoyancy, the strokes-per-metre increased slightly in the buoyancy-aided direction (descending), but decreased significantly in the buoyancy-hindered direction (ascending), with associated changes in swim speed and gliding duration. Overall, the round-trip strokes-per-metre decreased and reached a minimum value when seals achieved neutral buoyancy. Consistent with foraging theory, seals stayed longer at foraging depths when their round-trip strokes-per-metre was less. Therefore, neutrally buoyant divers gained an energetic advantage via reduced swimming costs, which resulted in an increase in time spent foraging at depth, suggesting a foraging benefit of being fat. PMID:25377461

Living marine resources of the Chukchi Sea: a resource report for the Chukchi Sea oil and gas lease sale Number 85. Technical memo

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morris, B.F.

1981-04-01

An area of the outer continental shelf of the northeastern Chukchi Sea is currently proposed by the Department of the Interior's Bureau of Land Management for oil and gas leasing in February 1985. The report assesses the biological resources of the northeastern Chukchi Sea that may be at risk from petroleum exploration and development, and proposes research needs to minimize and avoid potential biological impacts. The Chukchi Sea supports large populations of marine mammals and seabirds, which depend on the fish and invertebrate populations of the region. The marine mammals of major importance in the region are the bowhead whale,more » gray whale, beluga whale, walrus, ringed seal, bearded seal, spotted seal, and polar bear. Less frequent but regular visitors to the area are the fin, minke, humpback, and killer whales, the harbor porpoise, and ribbon seals.« less

Phocine Distemper Virus in Seals, East Coast, United States, 2006

PubMed Central

Earle, J.A. Philip; Melia, Mary M.; Doherty, Nadine V.; Nielsen, Ole

2011-01-01

In 2006 and 2007, elevated numbers of deaths among seals, constituting an unusual mortality event, occurred off the coasts of Maine and Massachusetts, United States. We isolated a virus from seal tissue and confirmed it as phocine distemper virus (PDV). We compared the viral hemagglutinin, phosphoprotein, and fusion (F) and matrix (M) protein gene sequences with those of viruses from the 1988 and 2002 PDV epizootics. The virus showed highest similarity with a PDV 1988 Netherlands virus, which raises the possibility that the 2006 isolate from the United States might have emerged independently from 2002 PDVs and that multiple lineages of PDV might be circulating among enzootically infected North American seals. Evidence from comparison of sequences derived from different tissues suggested that mutations in the F and M genes occur in brain tissue that are not present in lung, liver, or blood, which suggests virus persistence in the central nervous system. PMID:21291591

New-Generation Sealing Slurries For Borehole Injection Purposes

NASA Astrophysics Data System (ADS)

Stryczek, Stanisław; Gonet, Andrzej; Wiśniowski, Rafał; Złotkowski, Albert

2015-12-01

The development of techniques and technologies thanks to which parameters of the ground medium can be modified makes specialists look for new recipes of geopolymers - binders for the reinforcing and sealing of unstable and permeable grounds. The sealing slurries are expected to meet a number of strict requirements, therefore it is important to find new admixtures and additives which could modify the fresh and hardened slurry. Special attention has been recently paid to the fluid ash - a by-product of the combustion of hard coals. However, the use of this additive is associated with the application of appropriate superplastifier. Laboratory analyses of rheological parameters of fresh sealing slurries and the ways of improving their liquidity by a properly selected third-generation superplastifier are presented in the paper. The slurries were based on Portland cement CEM I, milled granulated large-furnace slag and fly ash from fluidized-bed combustion of hard coal.

An atomistic model for cross-linked HNBR elastomers used in seals

NASA Astrophysics Data System (ADS)

Molinari, Nicola; Sutton, Adrian; Stevens, John; Mostofi, Arash

2015-03-01

Hydrogenated nitrile butadiene rubber (HNBR) is one of the most common elastomeric materials used for seals in the oil and gas industry. These seals sometimes suffer ``explosive decompression,'' a costly problem in which gases permeate a seal at the elevated temperatures and pressures pertaining in oil and gas wells, leading to rupture when the seal is brought back to the surface. The experimental evidence that HNBR and its unsaturated parent NBR have markedly different swelling properties suggests that cross-linking may occur during hydrogenation of NBR to produce HNBR. We have developed a code compatible with the LAMMPS molecular dynamics package to generate fully atomistic HNBR configurations by hydrogenating initial NBR structures. This can be done with any desired degree of cross-linking. The code uses a model of atomic interactions based on the OPLS-AA force-field. We present calculations of the dependence of a number of bulk properties on the degree of cross-linking. Using our atomistic representations of HNBR and NBR, we hope to develop a better molecular understanding of the mechanisms that result in explosive decompression.

Heat generation and hemolysis at the shaft seal in centrifugal blood pumps.

PubMed

Araki, K; Taenaka, Y; Wakisaka, Y; Masuzawa, T; Tatsumi, E; Nakatani, T; Baba, Y; Yagura, A; Eya, K; Toda, K

1995-01-01

The heat and hemolysis around a shaft seal were investigated. Materials were original pumps (Nikkiso HMS-15:N-original, and 3M Delphin:D-original), vane-removed pumps (Nvane(-), Dvane(-)), and a small chamber with a shaft coiled by nichrome wire (mock pump). The original pumps were driven at 500 mmHg and 5 L/min, and vane-removed pumps were driven at the same rotation number. An electrical powers of 0, 0.5, 2, and 10 W was supplied to the mock pumps. In vitro hemolytic testing showed that hemolytic indices were 0.027 g/100 L in N-original, 0.013 in Nvane(-), 0.061 in D-original, and 0.012 in Dvane(-). Measurement of heat with a thermally insulated water chamber showed total heat within the pump of 8.62 and 10.85 W, and heat at the shaft seal of 0.87 and 0.62 W in the Nikkiso and Delphin pumps, respectively. Hemolysis and heat generation of mock pumps remained low. The results indicate that the heat generated around the shaft seal was minimal. Hemolysis at the shaft-seal was considerable but not major. Local heat did not affect hemolysis. It was concluded that the shaft-seal affected hemolysis, not by local heat but friction itself.

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

PubMed Central

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. PMID:26017404

How Many Seals Were There? The Global Shelf Loss during the Last Glacial Maximum and Its Effect on the Size and Distribution of Grey Seal Populations

PubMed Central

Boehme, Lars; Thompson, Dave; Fedak, Mike; Bowen, Don; Hammill, Mike O.; Stenson, Garry B.

2012-01-01

Predicting how marine mammal populations respond to habitat changes will be essential for developing conservation management strategies in the 21st century. Responses to previous environmental change may be informative in the development of predictive models. Here we describe the likely effects of the last ice age on grey seal population size and distribution. We use satellite telemetry data to define grey seal foraging habitat in terms of the temperature and depth ranges exploited by the contemporary populations. We estimate the available extent of such habitat in the North Atlantic at present (between 1.42·106 km2 and 2.07·106 km2) and at the last glacial maximum (between 4.74·104 km2 and 2.11·105 km2); taking account of glacial and seasonal sea-ice coverage, estimated reductions of sea-level (123 m) and sea surface temperature hind-casts. Most of the extensive continental shelf waters (North Sea, Baltic Sea and Scotian Shelf), currently supporting >95% of grey seals, were unavailable during the last glacial maximum. A combination of lower sea-level and extensive ice-sheets, massively increased seasonal sea-ice coverage and southerly extent of cold water would have pushed grey seals into areas with no significant shelf waters. The habitat during the last glacial maximum might have been as small as 3% of today's extent and grey seal populations may have fallen to similarly low numbers. An alternative scenario involving a major change to a pelagic or bathy-pelagic foraging niche cannot be discounted. However, hooded seals currently dominate that niche and may have excluded grey seals from such habitat. If as seems likely, the grey seal population fell to very low levels it would have remained low for several thousand years before expanding into current habitats over the past 12,000 years or so. PMID:23300843

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

PubMed

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.

Toxic elements and organochlorines in harbor seals (Phoca vitulina richardsi), Kodiak, Alaska, USA

USGS Publications Warehouse

Miles, A.K.; Calkins, D.G.; Coon, N.C.

1992-01-01

Marine and estuarine habitats near urban or industrialized regions are vulnerable to contaminated runoff. Harbor seals (Phoca vitulina richardsi), which occur throughout much of the northern hemisphere, are useful mammalian biomonitors because they feed, reproduce, and rest near or on shore and are high-level trophic consumers. They have often been monitored for contaminants in Europe (Wagemann and Muir 1984). To date, no studies have been reported on contaminants in harbor seals from industrialized areas of Alaska. In the vicinity of Anchorage, Alaska's largest urban and industrial city, harbor seals are sedentary and limited to coastal waters; some movements have been documented but there is no evidence of extensive migrations. Although some harbor seals in the Kodiak Archipelago move up to 100 km along the shore, strong fidelity to specific haulout sites is more common (Pitcher and Calkins 1979). These seals eat mainly non-migratory fishes and octopi. Harbor seal numbers have declined substantially from unknown causes in the southern part of the Kodiak Archipelago. The Alaska Department of Fish and Game (ADF&G) suggested that the decline is a trend for the entire Kodiak region and other Alaskan waters. Contaminants have been suggested as a possible reason for the precipitous decline of Steller sea lions (Eumetopias jubatus) in the region (Braham et al. 1980), and were suspected in the decline of harbor seals. In this study, harbor seals were sampled from throughout the Kodiak Archipelago to determine concentrations of certain metals, metalloids, polychlorinated biphenyls (PCBs), and organochlorine pesticides, and to determine if these concentrations varied by sex or accumulated with age. All seals were collected within 75 km of Cook Inlet, an estuary next to Anchorage. The targeted elements or compounds were known to be toxic to a wide spectrum of organisms (e.g., MARC 1980; Eisler 1986).

Delay test generation for synchronous sequential circuits

NASA Astrophysics Data System (ADS)

Devadas, Srinivas

1989-05-01

We address the problem of generating tests for delay faults in non-scan synchronous sequential circuits. Delay test generation for sequential circuits is a considerably more difficult problem than delay testing of combinational circuits and has received much less attention. In this paper, we present a method for generating test sequences to detect delay faults in sequential circuits using the stuck-at fault sequential test generator STALLION. The method is complete in that it will generate a delay test sequence for a targeted fault given sufficient CPU time, if such a sequence exists. We term faults for which no delay test sequence exists, under out test methodology, sequentially delay redundant. We describe means of eliminating sequential delay redundancies in logic circuits. We present a partial-scan methodology for enhancing the testability of difficult-to-test of untestable sequential circuits, wherein a small number of flip-flops are selected and made controllable/observable. The selection process guarantees the elimination of all sequential delay redundancies. We show that an intimate relationship exists between state assignment and delay testability of a sequential machine. We describe a state assignment algorithm for the synthesis of sequential machines with maximal delay fault testability. Preliminary experimental results using the test generation, partial-scan and synthesis algorithm are presented.

Designing group sequential randomized clinical trials with time to event end points using a R function.

PubMed

Filleron, Thomas; Gal, Jocelyn; Kramar, Andrew

2012-10-01

A major and difficult task is the design of clinical trials with a time to event endpoint. In fact, it is necessary to compute the number of events and in a second step the required number of patients. Several commercial software packages are available for computing sample size in clinical trials with sequential designs and time to event endpoints, but there are a few R functions implemented. The purpose of this paper is to describe features and use of the R function. plansurvct.func, which is an add-on function to the package gsDesign which permits in one run of the program to calculate the number of events, and required sample size but also boundaries and corresponding p-values for a group sequential design. The use of the function plansurvct.func is illustrated by several examples and validated using East software. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Proceedings of the Conference on the Design of Experiments in Army Research, Development and Testing (29th)

DTIC Science & Technology

1984-06-01

SEQUENTIAL TESTING (Bldg. A, Room C) 1300-1330 ’ 1330-1415 1415-1445 1445-1515 BREAK 1515-1545 A TRUNCATED SEQUENTIAL PROBABILITY RATIO TEST J...suicide optical data operational testing reliability random numbers bootstrap methods missing data sequential testing fire support complex computer model carcinogenesis studies EUITION Of 1 NOV 68 I% OBSOLETE a ...contributed papers can be ascertained from the titles of the

Longer and less overlapping food webs in anthropogenically disturbed marine ecosystems: confirmations from the past.

PubMed

Saporiti, Fabiana; Bearhop, Stuart; Silva, Laura; Vales, Damián G; Zenteno, Lisette; Crespo, Enrique A; Aguilar, Alex; Cardona, Luis

2014-01-01

The human exploitation of marine resources is characterised by the preferential removal of the largest species. Although this is expected to modify the structure of food webs, we have a relatively poor understanding of the potential consequences of such alteration. Here, we take advantage of a collection of ancient consumer tissues, using stable isotope analysis and SIBER to assess changes in the structure of coastal marine food webs in the South-western Atlantic through the second half of the Holocene as a result of the sequential exploitation of marine resources by hunter-gatherers, western sealers and modern fishermen. Samples were collected from shell middens and museums. Shells of both modern and archaeological intertidal herbivorous molluscs were used to reconstruct changes in the stable isotopic baseline, while modern and archaeological bones of the South American sea lion Otaria flavescens, South American fur seal Arctocephalus australis and Magellanic penguin Spheniscus magellanicus were used to analyse changes in the structure of the community of top predators. We found that ancient food webs were shorter, more redundant and more overlapping than current ones, both in northern-central Patagonia and southern Patagonia. These surprising results may be best explained by the huge impact of western sealing on pinnipeds during the fur trade period, rather than the impact of fishing on fish populations. As a consequence, the populations of pinnipeds at the end of the sealing period were likely well below the ecosystem's carrying capacity, which resulted in a release of intraspecific competition and a shift towards larger and higher trophic level prey. This in turn led to longer and less overlapping food webs.

Germanium detector vacuum encapsulation

NASA Technical Reports Server (NTRS)

Madden, N. W.; Malone, D. F.; Pehl, R. H.; Cork, C. P.; Luke, P. N.; Landis, D. A.; Pollard, M. J.

1991-01-01

This paper describes an encapsulation technology that should significantly improve the viability of germanium gamma-ray detectors for a number of important applications. A specialized vacuum chamber has been constructed in which the detector and the encapsulating module are processed in high vacuum. Very high vacuum conductance is achieved within the valveless encapsulating module. The detector module is then sealed without breaking the chamber vacuum. The details of the vacuum chamber, valveless module, processing, and sealing method are presented.

Preparation of wafer-level glass cavities by a low-cost chemical foaming process (CFP).

PubMed

Shang, Jintang; Chen, Boyin; Lin, Wei; Wong, Ching-Ping; Zhang, Di; Xu, Chao; Liu, Junwen; Huang, Qing-An

2011-04-21

A novel foaming process-chemical foaming process (CFP)-using foaming agents to fabricate wafer-level micro glass cavities including channels and bubbles was investigated. The process consists of the following steps sequentially: (1) shallow cavities were fabricated by a wet etching on a silicon wafer; (2) powders of a proper foaming agent were placed in a silicon cavity, named 'mother cavity', on the etched silicon surface; (3) the silicon cavities were sealed with a glass wafer by anodic bonding; (4) the bonded wafers were heated to above the softening point of the glass, and baked for several minutes, when the gas released by the decomposition of the foaming agent in the 'mother cavity' went into the other sealed interconnected silicon cavities to foam the softened glass into cylindrical channels named 'daughter channels', or spherical bubbles named 'son bubbles'. Results showed that wafer-level micro glass cavities with smooth wall surfaces were achieved successfully without contamination by the CFP. A model for the CFP was proposed to predict the final shape of the glass cavity. Experimental results corresponded with model predictions. The CFP provides a low-cost avenue to preparation of micro glass cavities of high quality for applications such as micro-reactors, micro total analysis systems (μTAS), analytical and bio-analytical applications, and MEMS packaging.

Killer whales and marine mammal trends in the North Pacific - A re-examination of evidence for sequential megafauna collapse and the prey-switching hypothesis

USGS Publications Warehouse

Wade, P.R.; Burkanov, V.N.; Dahlheim, M.E.; Friday, N.A.; Fritz, L.W.; Loughlin, Thomas R.; Mizroch, S.A.; Muto, M.M.; Rice, D.W.; Barrett-Lennard, L. G.; Black, N.A.; Burdin, A.M.; Calambokidis, J.; Cerchio, S.; Ford, J.K.B.; Jacobsen, J.K.; Matkin, C.O.; Matkin, D.R.; Mehta, A.V.; Small, R.J.; Straley, J.M.; McCluskey, S.M.; VanBlaricom, G.R.; Clapham, P.J.

2007-01-01

Springer et al. (2003) contend that sequential declines occurred in North Pacific populations of harbor and fur seals, Steller sea lions, and sea otters. They hypothesize that these were due to increased predation by killer whales, when industrial whaling's removal of large whales as a supposed primary food source precipitated a prey switch. Using a regional approach, we reexamined whale catch data, killer whale predation observations, and the current biomass and trends of potential prey, and found little support for the prey-switching hypothesis. Large whale biomass in the Bering Sea did not decline as much as suggested by Springer et al., and much of the reduction occurred 50-100 yr ago, well before the declines of pinnipeds and sea otters began; thus, the need to switch prey starting in the 1970s is doubtful. With the sole exception that the sea otter decline followed the decline of pinnipeds, the reported declines were not in fact sequential. Given this, it is unlikely that a sequential megafaunal collapse from whales to sea otters occurred. The spatial and temporal patterns of pinniped and sea otter population trends are more complex than Springer et al. suggest, and are often inconsistent with their hypothesis. Populations remained stable or increased in many areas, despite extensive historical whaling and high killer whale abundance. Furthermore, observed killer whale predation has largely involved pinnipeds and small cetaceans; there is little evidence that large whales were ever a major prey item in high latitudes. Small cetaceans (ignored by Springer et al.) were likely abundant throughout the period. Overall, we suggest that the Springer et al. hypothesis represents a misleading and simplistic view of events and trophic relationships within this complex marine ecosystem. ?? 2007 by the Society for Marine Mammalogy.

Turbulence measurements of high shear flow fields in a turbomachine seal configuration

NASA Technical Reports Server (NTRS)

Morrison, Gerald L.; Deotte, Robert E., Jr.; Thames, H. Davis, III.

1992-01-01

The mean velocity and Reynolds stress tensor throughout a whirling annular seal are presented. The data was collected with a three dimensional laser Doppler velocimeter using phase averaging. Two axial flow conditions (Re = 12,000 and 24,000) were studied at one shaft speed (Ta = 6,600). The eccentricity and whirl ratios were 50 and 100 percent, respectively. There is a region of high axial momentum in this region is higher in the low Reynolds number case due to an axial recirculation zone that occurs on the suction side of the rotor at the inlet. The recirculation zone does not occur in the high Reynolds number case. At both Reynolds numbers, there is a recirculation zone on the rotor surface in the pressure side of the inlet. This recirculation zone extends from 20 to 200 degrees rotor zenith in the tangential direction, and is one third of a clearance wide radially. The high Reynolds number recirculation zone is 1.5 mean clearances long, while the low Reynolds number zone extends 2 mean clearances downstream. When compared to previous studies, it is apparent that the tangential momentum is no greater for a seal with whirl than for one without if other parameters are constant. Areas of high tangential momentum occur in the clearance where the axial momentum is low. Average exit plane tangential velocities in the high Reynolds number case are 1.5 times greater than those in the other flow case. These results are in general agreement with predictions made by other investigators.

RACE/A: an architectural account of the interactions between learning, task control, and retrieval dynamics.

PubMed

van Maanen, Leendert; van Rijn, Hedderik; Taatgen, Niels

2012-01-01

This article discusses how sequential sampling models can be integrated in a cognitive architecture. The new theory Retrieval by Accumulating Evidence in an Architecture (RACE/A) combines the level of detail typically provided by sequential sampling models with the level of task complexity typically provided by cognitive architectures. We will use RACE/A to model data from two variants of a picture-word interference task in a psychological refractory period design. These models will demonstrate how RACE/A enables interactions between sequential sampling and long-term declarative learning, and between sequential sampling and task control. In a traditional sequential sampling model, the onset of the process within the task is unclear, as is the number of sampling processes. RACE/A provides a theoretical basis for estimating the onset of sequential sampling processes during task execution and allows for easy modeling of multiple sequential sampling processes within a task. Copyright © 2011 Cognitive Science Society, Inc.

Reaction of the lateral periodontium of dogs' teeth to contaminated and noncontaminated perforations filled with mineral trioxide aggregate.

PubMed

Holland, Roberto; Bisco Ferreira, Luciana; de Souza, Valdir; Otoboni Filho, José Arlindo; Murata, Sueli Satomi; Dezan, Eloi

2007-10-01

It has been shown that the mineral trioxide aggregate (MTA) used to seal lateral/furcal perforations stimulates the deposition of newly formed cementum. Nevertheless, when the site of the perforation is contaminated, the healing process might occur under less favorable conditions. This study evaluated the repair healing process of noncontaminated and contaminated lateral perforations filled with MTA and the effect of previously filling the contaminated perforations with a bactericidal agent. Thirty lateral root perforations were prepared in endodontically treated dog's teeth, thus forming 3 groups with 10 specimens each. In group 1 the perforations were immediately sealed with MTA. In group 2 the perforations were left open for 7 days and thereafter sealed with MTA. In group 3 the perforations were left open for 7 days, filled temporarily with a calcium hydroxide-based paste for 14 days, and then sealed with MTA. The animals were killed after 90 days, and the pieces were prepared for histomorphologic and histomicrobiologic evaluations. The statistical analysis showed that group 1 had significantly better repair than groups 2 (P < .05) and 3 (P < .05), which validates the superior results obtained when MTA was immediately used to seal root perforations. Groups 2 and 3 had statistically similar repair to each other (P > .05). There were a larger number of cases of complete or partial biologic seal in group 1 compared with the contaminated groups. It might be concluded that the lateral root perforations sealed with MTA after contamination presented worse repair than the noncontaminated, immediately sealed perforations. The temporary filling with a bactericidal agent (calcium hydroxide-based paste) did not improve the repair of perforations exposed to contamination, and the contaminated groups presented similar results to each other.

Natural selection on marine carnivores elaborated a diverse family of classical MHC class I genes exhibiting haplotypic gene content variation and allelic polymorphism

PubMed Central

Norman, Paul J.; Parham, Peter

2012-01-01

Pinnipeds, marine carnivores, diverged from terrestrial carnivores ~45 million years ago, before their adaptation to marine environments. This lifestyle change exposed pinnipeds to different microbiota and pathogens, with probable impact on their MHC class I genes. Investigating this question, genomic sequences were determined for 71 MHC class I variants: 27 from harbor seal and 44 from gray seal. These variants form three MHC class I gene lineages, one comprising a pseudogene. The second, a candidate nonclassical MHC class I gene, comprises a nonpolymorphic transcribed gene related to dog DLA-79 and giant panda Aime-1906. The third is the diversity lineage, which includes 62 of the 71 seal MHC class I variants. All are transcribed, and they minimally represent six harbor and 12 gray seal MHC class I genes. Besides species-specific differences in gene number, seal MHC class I haplotypes exhibit gene content variation and allelic polymorphism. Patterns of sequence variation, and of positions for positively selected sites, indicate the diversity lineage genes are the seals’ classical MHC class I genes. Evidence that expansion of diversity lineage genes began before gray and harbor seals diverged is the presence in both species of two distinctive sublineages of diversity lineage genes. Pointing to further expansion following the divergence are the presence of species-specific genes and greater MHC class I diversity in gray seals than harbor seals. The elaboration of a complex variable family of classical MHC class I genes in pinnipeds contrasts with the single, highly polymorphic classical MHC class I gene of dog and giant panda, terrestrial carnivores. PMID:23001684

Glass composition and process for sealing void spaces in electrochemical devices

DOEpatents

Meinhardt, Kerry D [Richland, WA; Kirby, Brent W [Kennewick, WA

2012-05-01

A glass foaming material and method are disclosed for filling void spaces in electrochemical devices. The glass material includes a reagent that foams at a temperature above the softening point of the glass. Expansion of the glass fills void spaces including by-pass and tolerance channels of electrochemical devices. In addition, cassette to cassette seals can also be formed while channels and other void spaces are filled, reducing the number of processing steps needed.

The foraging benefits of being fat in a highly migratory marine mammal.

PubMed

Adachi, Taiki; Maresh, Jennifer L; Robinson, Patrick W; Peterson, Sarah H; Costa, Daniel P; Naito, Yasuhiko; Watanabe, Yuuki Y; Takahashi, Akinori

2014-12-22

Foraging theory predicts that breath-hold divers adjust the time spent foraging at depth relative to the energetic cost of swimming, which varies with buoyancy (body density). However, the buoyancy of diving animals varies as a function of their body condition, and the effects of these changes on swimming costs and foraging behaviour have been poorly examined. A novel animal-borne accelerometer was developed that recorded the number of flipper strokes, which allowed us to monitor the number of strokes per metre swam (hereafter, referred to as strokes-per-metre) by female northern elephant seals over their months-long, oceanic foraging migrations. As negatively buoyant seals increased their fat stores and buoyancy, the strokes-per-metre increased slightly in the buoyancy-aided direction (descending), but decreased significantly in the buoyancy-hindered direction (ascending), with associated changes in swim speed and gliding duration. Overall, the round-trip strokes-per-metre decreased and reached a minimum value when seals achieved neutral buoyancy. Consistent with foraging theory, seals stayed longer at foraging depths when their round-trip strokes-per-metre was less. Therefore, neutrally buoyant divers gained an energetic advantage via reduced swimming costs, which resulted in an increase in time spent foraging at depth, suggesting a foraging benefit of being fat. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Static and Dynamic Pressure Distributions in a Short Labyrinth Seal

NASA Technical Reports Server (NTRS)

Millsaps, K. T.; Martinez-Sanchez, M.

1991-01-01

As part of a study into turbine blade tip destabilizing forces, a seals test rig was built in which spin rate, circular whirl rate, direction and amplitude of inlet swirl angle, and eccentricity can all be controlled over wide ranges, and measurements can be made at gap Reynolds numbers up to about 2 x 10(exp 4). This facility is described and preliminary data is presented for a one cavity labyrinth seal with a flat, stator mounted land. The impact of different flow coefficients for the first and second knives on the rotordynamic coefficients was found. While this effect is dominant for the direct forces, it should also be incorporated into calculations of cross forces where it has an impact under many conditions.

Solid state switch panel. [determination of optimum transducer type for required switches

NASA Technical Reports Server (NTRS)

Beenfeldt, E.

1973-01-01

An intensive study of various forms of transducers was conducted with application towards hermetically sealing the transducer and all electronics. The results of the study indicated that the Hall effect devices and a LED/phototransistor combination were the most practical for this type of application. Therefore, hardware was developed utilizing a magnet/Hall effect transducer for single action switches and LED/phototransistor transducers for rotary multiposition or potentiometer applications. All electronics could be housed in a hermetically sealed compartment. A number of switches were built and models were hermetically sealed to prove the feasibility of this type of fabrication. One of each type of switch was subjected to temperature cycling, vibration, and EMI tests. The results of these tests are presented.

Data Networks Reliability

DTIC Science & Technology

1988-10-03

full achievable region is achievable if there is only a bounded degree of asynchronism. E. Arikan , in a Ph.D. thesis [Ari85], extended sequential...real co-operation is required to reduce the number of transmissions to O(log log N). 14 REFERENCES [Ari85] E. Arikan , "Sequential Decoding for Multiple

76 FR 21387 - Federal Property Suitable as Facilities To Assist the Homeless

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-15

... GSA Number: 4-G-WV-0557 Comments: 57,600 sq. ft; future owners must maintain exposure prevention... Number: 9-N-CA-1508-AI Comments: Correction: 631.62 sq. ft., encroachment. Parcel F-4 Right of Way Seal...

Spontaneous delayed sealing in selected patients with a primary type-Ia endoleak after endovascular aneurysm repair.

PubMed

Bastos Gonçalves, F; Verhagen, H J M; Vasanthananthan, K; Zandvoort, H J A; Moll, F L; van Herwaarden, J A

2014-07-01

Direct additional therapy is advised for type-Ia endoleaks detected on completion angiography after endovascular aneurysm repair (EVAR). Additional intraoperative endovascular procedures are, however, often challenging or not possible, and direct open conversion is unattractive. The results of a selective, conservative strategy for patients with primary type-Ia endoleak has been analysed. This was a retrospective, single-centre study (UMC, Utrecht, NL). From 2004 to 2008, all patients with a primary type-Ia endoleak and suitable anatomy for EVAR, stentgraft oversizing ≥15%, and optimal deployment were included. Complications during follow-up were studied and all sequential CTA scans were reviewed. These were compared with the remaining patients, treated during the same period. Fifteen patients were included (14 male, median age 77, range 67-85) with a median aneurysm diameter of 60 mm (48-80), an aneurysm neck diameter of 26 mm (21-32), a neck length of 29 mm (11-39), and infrarenal angulation of 49° (31-90). One patient suffered rupture 2 days after EVAR - leading to the only AAA-related death. Eight of the 15 type-Ia endoleaks disappeared spontaneously on the first postoperative CTA, obtained within 1 week of EVAR. On the second postoperative CTA, obtained a median of 5 months (1-12) after EVAR, all remaining endoleaks had sealed. One recurrence occurred at 4.85 years. During a median follow-up of 3.3 years, there were five secondary interventions. Compared with controls, there were more secondary (or recurrent) type-1a endoleaks (13% vs. 4%), endograft migrations (13% vs. 3%), sac growths (33% vs. 16%), and secondary interventions (33% vs. 23%). None of these differences however, were statistically significant. All but one of the primary type-Ia endoleaks sealed spontaneously. Until sealing, the risk of rupture persisted, but subsequently only one recurrence of type-Ia endoleak was seen. In selected patients, a conservative approach for primary type-Ia endoleaks may be justified. Copyright © 2014 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

Solids feeder apparatus

DOEpatents

Bell, Jr., Harold S.

1979-01-01

This invention sets forth a double-acting piston, which carries a floating piston, and which is reciprocated in a housing, for feeding coal to a high pressure gasifier system. The housing has a plurality of solids (for instance: coal) in-feeding ports and a single discharge port, the latter port being in communication with a high pressure gasifier system. The double-acting piston sequentially and individually communicates each of the in-feeding ports with the discharge port. The floating piston both seals off the discharge port while each in-feeding port is receiving coal or the like, to prevent undue escape of gas from the gasifier system, and translates in the housing, following a discharge of coal or the like into the discharge port, to return gas which has been admitted into the housing back into the gasifier system.

Numerical simulation for the coupled thermo-mechanical performance of a lined rock cavern for underground compressed air energy storage

NASA Astrophysics Data System (ADS)

Zhou, Shu-Wei; Xia, Cai-Chu; Zhao, Hai-Bin; Mei, Song-Hua; Zhou, Yu

2017-12-01

Compressed air energy storage (CAES) is a technology that uses compressed air to store surplus electricity generated from low power consumption time for use at peak times. This paper presents a thermo-mechanical modeling for the thermodynamic and mechanical responses of a lined rock cavern used for CAES. The simulation was accomplished in COMSOL Multiphysics and comparisons of the numerical simulation and some analytical solutions validated the thermo-mechanical modeling. Air pressure and temperatures in the sealing layer and concrete lining exhibited a similar trend of ‘up-down-down-up’ in one cycle. Significant temperature fluctuation occurred only in the concrete lining and sealing layer, and no strong fluctuation was observed in the host rock. In the case of steel sealing, principal stresses in the sealing layer were larger than those in the concrete and host rock. The maximum compressive stresses of the three layers and the displacement on the cavern surface increased with the increase of cycle number. However, the maximum tensile stresses exhibited the opposite trend. Polymer sealing achieved a relatively larger air temperature and pressure compared with steel and air-tight concrete sealing. For concrete layer thicknesses of 0 and 0.1 m and an initial air pressure of 4.5 MPa, the maximum rock temperature could reach 135 °C and 123 °C respectively in a 30 day simulation.

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

USGS Publications Warehouse

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

2006-01-01

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

Hematology, Serum Chemistry, and Early Hematologic Changes in Free-Ranging South American Fur Seals ( Arctocephalus australis ) at Guafo Island, Chilean Patagonia.

PubMed

Seguel, Mauricio; Muñoz, Francisco; Keenan, Alessandra; Perez-Venegas, Diego J; DeRango, Eugene; Paves, Hector; Gottdenker, Nicole; Müller, Ananda

2016-07-01

The establishment of clinical pathology baseline data is critical to evaluate temporal and spatial changes in marine mammal groups. Despite increased availability of studies on hematology and biochemistry of marine mammals, reference ranges are lacking for many populations, especially among fur seal species. During the austral summers of 2014 and 2015, we evaluated basic hematologic and biochemical parameters in clinically healthy, physically restrained South American fur seal ( Arctocephalus australis ) lactating females and 2-mo-old pups. We also assessed the temporal variation of hematology parameters on the pups during their first 2 mo of life. Reference ranges of lactating females were similar to those previously reported in other fur seal species. In the case of pups, reference ranges are similar to values previously reported in sea lion species. As expected, most biochemical and hematologic values differ significantly between adult females and pups. As in other otariids, South American fur seals pups are born with higher values of total red blood cells, hemoglobin, and packed cell volume, and lower numbers of total leukocytes, neutrophils, lymphocytes, and eosinophils. To the best of our knowledge, data on hematology reference values for South American fur seals has not been previously reported and is useful for continued health monitoring of this species, as well as for comparisons with other otariid groups.

Stationary Anonymous Sequential Games with Undiscounted Rewards.

PubMed

Więcek, Piotr; Altman, Eitan

Stationary anonymous sequential games with undiscounted rewards are a special class of games that combine features from both population games (infinitely many players) with stochastic games. We extend the theory for these games to the cases of total expected reward as well as to the expected average reward. We show that in the anonymous sequential game equilibria correspond to the limits of those of related finite population games as the number of players grows to infinity. We provide examples to illustrate our results.

Development of intermediate temperature sodium nickel chloride rechargeable batteries using conventional polymer sealing technologies

NASA Astrophysics Data System (ADS)

Chang, Hee Jung; Lu, Xiaochuan; Bonnett, Jeff F.; Canfield, Nathan L.; Son, Sori; Park, Yoon-Cheol; Jung, Keeyoung; Sprenkle, Vincent L.; Li, Guosheng

2017-04-01

Developing advanced and reliable electrical energy storage systems is critical to fulfill global energy demands and stimulate the growth of renewable energy resources. Sodium metal halide batteries have been under serious consideration as a low cost alternative energy storage device for stationary energy storage systems. Yet, there are number of challenges to overcome for the successful market penetration, such as high operating temperature and hermetic sealing of batteries that trigger an expensive manufacturing process. Here we demonstrate simple, economical and practical sealing technologies for Na-NiCl2 batteries operated at an intermediate temperature of 190 °C. Conventional polymers are implemented in planar Na-NiCl2 batteries after a prescreening test, and their excellent compatibilities and durability are demonstrated by a stable performance of Na-NiCl2 battery for more than 300 cycles. The sealing methods developed in this work will be highly beneficial and feasible for prolonging battery cycle life and reducing manufacturing cost for Na-based batteries at elevated temperatures (<200 °C).

Fabrication and testing of negative limited sealed nickel-cadmium cells

NASA Technical Reports Server (NTRS)

Gordy, D. J.

1975-01-01

A number of 20 Ah and 3 Ah negative limited nickel-cadmium cells were fabricated and assembled in hermetically sealed stainless steel containers. The cells exhibit a large voltage rise signal, in excess of 250 mA, at the end of each charge period. They also exhibit lower self discharge rates than conventional sealed nickel-cadmium cells and do not require overcharge. The cells are capable of operating at charge and discharge rates up to 5C and can deliver at least 1000 cycles on a 30 minute regime at 25% DOD. A small amount of gassing occurs, but is not deemed critical or detrimental in view of the facts that, (1) operating pressures are in the range of 7 to 20 psig and (2) the cells are operated in the flooded condition so therefore contain little internal void volume. The cells were found to exhibit somewhat higher capacity loss rates during cycling than conventional sealed nickel-cadmium batteries.

Engine Seal Technology Requirements to Meet NASA's Advanced Subsonic Technology Program Goals

NASA Technical Reports Server (NTRS)

Steinetz, Bruce M.; Hendricks, Robert C.

1994-01-01

Cycle studies have shown the benefits of increasing engine pressure ratios and cycle temperatures to decrease engine weight and improve performance of commercial turbine engines. NASA is working with industry to define technology requirements of advanced engines and engine technology to meet the goals of NASA's Advanced Subsonic Technology Initiative. As engine operating conditions become more severe and customers demand lower operating costs, NASA and engine manufacturers are investigating methods of improving engine efficiency and reducing operating costs. A number of new technologies are being examined that will allow next generation engines to operate at higher pressures and temperatures. Improving seal performance - reducing leakage and increasing service life while operating under more demanding conditions - will play an important role in meeting overall program goals of reducing specific fuel consumption and ultimately reducing direct operating costs. This paper provides an overview of the Advanced Subsonic Technology program goals, discusses the motivation for advanced seal development, and highlights seal technology requirements to meet future engine performance goals.

Computerized Classification Testing with the Rasch Model

ERIC Educational Resources Information Center

Eggen, Theo J. H. M.

2011-01-01

If classification in a limited number of categories is the purpose of testing, computerized adaptive tests (CATs) with algorithms based on sequential statistical testing perform better than estimation-based CATs (e.g., Eggen & Straetmans, 2000). In these computerized classification tests (CCTs), the Sequential Probability Ratio Test (SPRT) (Wald,…

Investigations of peritoneal and intestinal infections of adult hookworms (Uncinaria spp.) in northern fur seal (Callorhinus ursinus) and California sea lion (Zalophus californianus) pups on San Miguel Island, California (2003).

PubMed

Lyons, Eugene T; Delong, R L; Nadler, S A; Laake, J L; Orr, A J; Delong, B L; Pagan, C

2011-09-01

The peritoneal cavity (PNC) and intestine of northern fur seal (Callorhinus ursinus) pups and California sea lion (Zalophus californianus) pups that died in late July and early August, 2003, on San Miguel Island, California, were examined for hookworms. Prevalence and morphometric studies were done with the hookworms in addition to molecular characterization. Based on this and previous molecular studies, hookworms from fur seals are designated as Uncinaria lucasi and the species from sea lions as Uncinaria species A. Adult hookworms were found in the PNC of 35 of 57 (61.4%) fur seal pups and of 13 of 104 (12.5%) sea lion pups. The number of hookworms located in the PNC ranged from 1 to 33 (median = 3) for the infected fur seal pups and 1 to 16 (median = 2) for the infected sea lion pups. In addition to the PNC, intestines of 43 fur seal and 32 sea lion pups were examined. All of these pups were positive for adult hookworms. The worms were counted from all but one of the sea lion pups. Numbers of these parasites in the intestine varied from 3 to 2,344 (median = 931) for the fur seal pups and 39 to 2,766 (median = 643) for the sea lion pups. Sea lion pups with peritoneal infections had higher intensity infections in the intestines than did pups without peritoneal infections, lending some support for the hypothesis that peritoneal infections result from high-intensity infections of adult worms. There was no difference in intestinal infection intensities between fur seal pups with and without peritoneal infections. Female adult hookworms in the intestines of both host species were significantly larger than males, and sea lion hookworms were larger than those in fur seals. Worms in the intestine also were larger than worms found in the PNC. Gene sequencing and (RFLP) analysis of (PCR) amplified (ITS) ribosomal DNA were used to diagnose the species of 172 hookworms recovered from the PNC and intestine of 18 C. ursinus and seven Z. californianus hosts. These molecular data revealed that U. lucasi (hookworm of C. ursinus) and Uncinaria species A (of Z. californianus) infrequently mature in the intestine of the opposite host species in California rookeries. However, there is no support from molecular data for the hypothesis that cross-infection with "the wrong" Uncinaria species is a contributing factor in these cases of host peritonitis. The major significance of this research is the unusual finding of adult hookworms in the PNC of so many dead pups. No obvious explanation for this occurrence could be determined. Further research, like in the present study, should help understand and monitor the apparent ever changing role of hookworm disease in the health of northern fur seal and California sea lion pups on SMI.

New data on Weddell seal (Leptonychotes weddellii) colonies: A genetic analysis of a top predator from the Ross Sea, Antarctica

PubMed Central

Fabiani, Anna; Sbordoni, Valerio; Rakaj, Arnold; Palozzi, Roberto; Allegrucci, Giuliana

2017-01-01

In this paper, we studied the genetic variability in Weddell seal from colonies in Terra Nova Bay and Wood Bay, both sites located in the Ross Sea area, Antarctica. Two mitochondrial genes and one nuclear gene, with different mutation rates, were sequenced to investigate the haplotype diversity of the colonies and to test for a possible recent expansion. Fifteen microsatellites were used to analyze their genetic structure. Sequenced genes and microsatellites were also used to estimate the effective population size of the studied colonies and the Ross Sea seal population. The Ross Sea has a high density population of Weddel seals, with an estimated effective number of 50,000 females, and 1,341 individuals for the sampling area, possibly due to its high primary production. The colonies showed high diversity (Hd > 0.90) and many exclusive haplotypes (> 75%), likely a consequence of the surprisingly high site fidelity of Weddell seals, despite the proximity of the colonies. Nevertheless, there was low microsatellite differentiation between colonies, suggesting that they are part of a single larger population. Their expansion seemed to have started during the last glacial cycle (around 58,000 years ago), indicating that the Ross Sea seal populations have been present in the area for long time, probably due to the lack of hunting by humans and terrestrial predation. As a top predator, the role of Weddell seals in the Ross Sea ecology is crucial, and its demographic dynamics should be monitored to follow the future changes of such an important ecosystem. PMID:28796829

TH-CD-202-04: Evaluation of Virtual Non-Contrast Images From a Novel Split-Filter Dual-Energy CT Technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, J; Szczykutowicz, T; Bayouth, J

Purpose: To compare the ability of two dual-energy CT techniques, a novel split-filter single-source technique of superior temporal resolution against an established sequential-scan technique, to remove iodine contrast from images with minimal impact on CT number accuracy. Methods: A phantom containing 8 tissue substitute materials and vials of varying iodine concentrations (1.7–20.1 mg I /mL) was imaged using a Siemens Edge CT scanner. Dual-energy virtual non-contrast (VNC) images were generated using the novel split-filter technique, in which a 120kVp spectrum is filtered by tin and gold to create high- and low-energy spectra with < 1 second temporal separation between themore » acquisition of low- and high-energy data. Additionally, VNC images were generated with the sequential-scan technique (80 and 140kVp) for comparison. CT number accuracy was evaluated for all materials at 15, 25, and 35mGy CTDIvol. Results: The spectral separation was greater for the sequential-scan technique than the split-filter technique with dual-energy ratios of 2.18 and 1.26, respectively. Both techniques successfully removed iodine contrast, resulting in mean CT numbers within 60HU of 0HU (split-filter) and 40HU of 0HU (sequential-scan) for all iodine concentrations. Additionally, for iodine vials of varying diameter (2–20 mm) with the same concentration (9.9 mg I /mL), the system accurately detected iodine for all sizes investigated. Both dual-energy techniques resulted in reduced CT numbers for bone materials (by >400HU for the densest bone). Increasing the imaging dose did not improve the CT number accuracy for bone in VNC images. Conclusion: VNC images from the split-filter technique successfully removed iodine contrast. These results demonstrate a potential for improving dose calculation accuracy and reducing patient imaging dose, while achieving superior temporal resolution in comparison sequential scans. For both techniques, inaccuracies in CT numbers for bone materials necessitate consideration for radiation therapy treatment planning.« less

Contamination of the environment by special purpose centrifuges used in clinical laboratories.

PubMed Central

Harper, G J

1981-01-01

The generation of aerosols and the contamination of surfaces arising from the use of a number of special purpose centrifuges have been measured. Except when sealed containers were used all the equipment tested generated airborne particles and contaminated surrounding surfaces. The magnitude of this contamination was shown to be associated with several factors, and it could be considerably reduced by the use of sealed containers, and by fitting air filters. The significance of these findings and their application are discussed. PMID:7031096

Rotordynamic Forces Developed by Labyrinth Seals

DTIC Science & Technology

1984-11-01

the prediction of leakage and the rotordynamic coefficients of Eq. (1) for labyrinth seals . A copy of reference DI) is attached. In comparison to... Leakage of Steam Through Labyrinth Glands," Trans. ASME, Vol. 57, 1935, pp. 115-122. 16. John, E. A. Jamea, Gas Dynamios, Wylie, 1979. -19- • ]{ o -Cr...Quadratic-Upstream Di iferemcing in Uigh Reynolds Number Illiptic a. Xgli. A.. ’"the Leakage of Steam Through Labyrinth flows," of P ohAa. ab o.. l 9

Development and Evaluation of Integrity Assessment Tests for Polymeric Hermetic Seals

DTIC Science & Technology

2006-02-19

Knoxville, the wires were pulled from the seals and then the packages were dipped in the microorganism Enterobacter aerogene . The polytrays were exposed for...inoculated) 5 samples Total Polytrays 80 Microorganism Washes 1. Prepare Cultures of Enterobacter aerogenes a. 5 tubes (10 mL each) in...initial number – 6 log CFU/mL a. Add two tubes (20 mL) of Enterobacter aerogenes culture to 5 gallons of water with sodium thiosulfate b. Ca. 9 log CFU

Trends and anomalies in gas evolution from coal samples

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vorres, K.S.

1993-09-01

As part of the stability studies on these sealed samples a number of the samples were given to the Analytical Chemistry Laboratory at ANL for periodic gas analysis. 1. Higher rank coals evolve methane, and lower rank coals evolve carbon dioxide with some evolution of both gases for the intermediate ranks. 2. The evolution proceeds over times of years for pulverized coals in sealed ampules. 3. Gas concentrations are higher above -20 mesh samples than above -100 mesh material. 4. Carbon monoxide is not evolved.

Implementing reduced-risk integrated pest management in fresh-market cabbage: influence of sampling parameters, and validation of binomial sequential sampling plans for the cabbage looper (Lepidoptera Noctuidae).

PubMed

Burkness, Eric C; Hutchison, W D

2009-10-01

Populations of cabbage looper, Trichoplusiani (Lepidoptera: Noctuidae), were sampled in experimental plots and commercial fields of cabbage (Brasicca spp.) in Minnesota during 1998-1999 as part of a larger effort to implement an integrated pest management program. Using a resampling approach and the Wald's sequential probability ratio test, sampling plans with different sampling parameters were evaluated using independent presence/absence and enumerative data. Evaluations and comparisons of the different sampling plans were made based on the operating characteristic and average sample number functions generated for each plan and through the use of a decision probability matrix. Values for upper and lower decision boundaries, sequential error rates (alpha, beta), and tally threshold were modified to determine parameter influence on the operating characteristic and average sample number functions. The following parameters resulted in the most desirable operating characteristic and average sample number functions; action threshold of 0.1 proportion of plants infested, tally threshold of 1, alpha = beta = 0.1, upper boundary of 0.15, lower boundary of 0.05, and resampling with replacement. We found that sampling parameters can be modified and evaluated using resampling software to achieve desirable operating characteristic and average sample number functions. Moreover, management of T. ni by using binomial sequential sampling should provide a good balance between cost and reliability by minimizing sample size and maintaining a high level of correct decisions (>95%) to treat or not treat.

Computationally inexpensive identification of noninformative model parameters by sequential screening

NASA Astrophysics Data System (ADS)

Cuntz, Matthias; Mai, Juliane; Zink, Matthias; Thober, Stephan; Kumar, Rohini; Schäfer, David; Schrön, Martin; Craven, John; Rakovec, Oldrich; Spieler, Diana; Prykhodko, Vladyslav; Dalmasso, Giovanni; Musuuza, Jude; Langenberg, Ben; Attinger, Sabine; Samaniego, Luis

2015-08-01

Environmental models tend to require increasing computational time and resources as physical process descriptions are improved or new descriptions are incorporated. Many-query applications such as sensitivity analysis or model calibration usually require a large number of model evaluations leading to high computational demand. This often limits the feasibility of rigorous analyses. Here we present a fully automated sequential screening method that selects only informative parameters for a given model output. The method requires a number of model evaluations that is approximately 10 times the number of model parameters. It was tested using the mesoscale hydrologic model mHM in three hydrologically unique European river catchments. It identified around 20 informative parameters out of 52, with different informative parameters in each catchment. The screening method was evaluated with subsequent analyses using all 52 as well as only the informative parameters. Subsequent Sobol's global sensitivity analysis led to almost identical results yet required 40% fewer model evaluations after screening. mHM was calibrated with all and with only informative parameters in the three catchments. Model performances for daily discharge were equally high in both cases with Nash-Sutcliffe efficiencies above 0.82. Calibration using only the informative parameters needed just one third of the number of model evaluations. The universality of the sequential screening method was demonstrated using several general test functions from the literature. We therefore recommend the use of the computationally inexpensive sequential screening method prior to rigorous analyses on complex environmental models.

Computationally inexpensive identification of noninformative model parameters by sequential screening

NASA Astrophysics Data System (ADS)

Mai, Juliane; Cuntz, Matthias; Zink, Matthias; Thober, Stephan; Kumar, Rohini; Schäfer, David; Schrön, Martin; Craven, John; Rakovec, Oldrich; Spieler, Diana; Prykhodko, Vladyslav; Dalmasso, Giovanni; Musuuza, Jude; Langenberg, Ben; Attinger, Sabine; Samaniego, Luis

2016-04-01

Environmental models tend to require increasing computational time and resources as physical process descriptions are improved or new descriptions are incorporated. Many-query applications such as sensitivity analysis or model calibration usually require a large number of model evaluations leading to high computational demand. This often limits the feasibility of rigorous analyses. Here we present a fully automated sequential screening method that selects only informative parameters for a given model output. The method requires a number of model evaluations that is approximately 10 times the number of model parameters. It was tested using the mesoscale hydrologic model mHM in three hydrologically unique European river catchments. It identified around 20 informative parameters out of 52, with different informative parameters in each catchment. The screening method was evaluated with subsequent analyses using all 52 as well as only the informative parameters. Subsequent Sobol's global sensitivity analysis led to almost identical results yet required 40% fewer model evaluations after screening. mHM was calibrated with all and with only informative parameters in the three catchments. Model performances for daily discharge were equally high in both cases with Nash-Sutcliffe efficiencies above 0.82. Calibration using only the informative parameters needed just one third of the number of model evaluations. The universality of the sequential screening method was demonstrated using several general test functions from the literature. We therefore recommend the use of the computationally inexpensive sequential screening method prior to rigorous analyses on complex environmental models.

Outcomes of simultaneous resections for patients with synchronous colorectal liver metastases.

PubMed

Slesser, A A P; Chand, M; Goldin, R; Brown, G; Tekkis, P P; Mudan, S

2013-12-01

The aim of this study was to determine the outcomes associated with simultaneous resections compared to patients undergoing sequential resections for synchronous colorectal liver metastases. Consecutive patients undergoing hepatic resections between 2000 and 2012 for synchronous colorectal liver metastases were identified from a prospectively maintained database. Of the 112 hepatic resections that were performed, 36 were simultaneous resections and 76 were sequential resections. There was no difference in disease severity: number of metastases (P 0.228), metastatic size (P 0.58), the primary tumour nodal status (P 0.283), CEA (P 0.387) or the presence of extra-hepatic metastases (P 1.0). Major hepatic resections were performed in 23 (64%) and 60 (79%) of patients in the simultaneous and sequential groups respectively (P 0.089). Intra-operatively no differences were found in blood loss (P 1.0), duration of surgery (P 0.284) or number of adverse events (P 1.0). There were no differences in post-operative complications (P 0.161) or post-operative mortality (P 0.241). The length of hospital stay was 14 (95% CI 12.0-18.0) and 18.5 (95% CI 16.0-23.0) days in the simultaneous and sequential groups respectively (P 0.03). The 3-year overall survival was 75% and 64% in the simultaneous and sequential groups respectively (P 0.379). The 3-year hepatic recurrence free survival was 61% and 46% in the simultaneous and sequential groups respectively (P 0.254). Simultaneous resections result in similar short-term and long-term outcomes as patients receiving sequential resections with comparable metastatic disease and are associated with a significant reduction in the length of stay. Copyright © 2013 Elsevier Ltd. All rights reserved.

Modelling predation by transient leopard seals for an ecosystem-based management of Southern Ocean fisheries

USGS Publications Warehouse

Forcada, J.; Malone, D.; Royle, J. Andrew; Staniland, I.J.

2009-01-01

Correctly quantifying the impacts of rare apex marine predators is essential to ecosystem-based approaches to fisheries management, where harvesting must be sustainable for targeted species and their dependent predators. This requires modelling the uncertainty in such processes as predator life history, seasonal abundance and movement, size-based predation, energetic requirements, and prey vulnerability. We combined these uncertainties to evaluate the predatory impact of transient leopard seals on a community of mesopredators (seals and penguins) and their prey at South Georgia, and assess the implications for an ecosystem-based management. The mesopredators are highly dependent on Antarctic krill and icefish, which are targeted by regional fisheries. We used a state-space formulation to combine (1) a mark-recapture open-population model and individual identification data to assess seasonally variable leopard seal arrival and departure dates, numbers, and residency times; (2) a size-based bioenergetic model; and (3) a size-based prey choice model from a diet analysis. Our models indicated that prey choice and consumption reflected seasonal changes in leopard seal population size and structure, size-selective predation and prey vulnerability. A population of 104 (90-125) leopard seals, of which 64% were juveniles, consumed less than 2% of the Antarctic fur seal pup production of the area (50% of total ingested energy, IE), but ca. 12-16% of the local gentoo penguin population (20% IE). Antarctic krill (28% IE) were the only observed food of leopard seal pups and supplemented the diet of older individuals. Direct impacts on krill and fish were negligible, but the "escapement" due to leopard seal predation on fur seal pups and penguins could be significant for the mackerel icefish fishery at South Georgia. These results suggest that: (1) rare apex predators like leopard seals may control, and may depend on, populations of mesopredators dependent on prey species targeted by fisheries; and (2) predatory impacts and community control may vary throughout the predator's geographic range, and differ across ecosystems and management areas, depending on the seasonal abundance of the prey and the predator's dispersal movements. This understanding is important to integrate the predator needs as natural mortality of its prey in models to set prey catch limits for fisheries. Reliable estimates of the variability of these needs are essential for a precautionary interpretation in the context of an ecosystem-based management. ?? 2009 Elsevier B.V.

Modelling predation by transient leopard seals for an ecosystem-based management of Southern Ocean fisheries

USGS Publications Warehouse

Forcada, J.; Royle, J. Andrew; Staniland, I.J.

2009-01-01

Correctly quantifying the impacts of rare apex marine predators is essential to ecosystem-based approaches to fisheries management, where harvesting must be sustainable for targeted species and their dependent predators. This requires modelling the uncertainty in such processes as predator life history, seasonal abundance and movement, size-based predation, energetic requirements, and prey vulnerability. We combined these uncertainties to evaluate the predatory impact of transient leopard seals on a community of mesopredators (seals and penguins) and their prey at South Georgia, and assess the implications for an ecosystem-based management. The mesopredators are highly dependent on Antarctic krill and icefish, which are targeted by regional fisheries. We used a state-space formulation to combine (1) a mark-recapture open-population model and individual identification data to assess seasonally variable leopard seal arrival and departure dates, numbers, and residency times; (2) a size-based bioenergetic model; and (3) a size-based prey choice model from a diet analysis. Our models indicated that prey choice and consumption reflected seasonal changes in leopard seal population size and structure, size-selective predation and prey vulnerability. A population of 104 (90?125) leopard seals, of which 64% were juveniles, consumed less than 2% of the Antarctic fur seal pup production of the area (50% of total ingested energy, IE), but ca. 12?16% of the local gentoo penguin population (20% IE). Antarctic krill (28% IE) were the only observed food of leopard seal pups and supplemented the diet of older individuals. Direct impacts on krill and fish were negligible, but the ?escapement? due to leopard seal predation on fur seal pups and penguins could be significant for the mackerel icefish fishery at South Georgia. These results suggest that: (1) rare apex predators like leopard seals may control, and may depend on, populations of mesopredators dependent on prey species targeted by fisheries; and (2) predatory impacts and community control may vary throughout the predator's geographic range, and differ across ecosystems and management areas, depending on the seasonal abundance of the prey and the predator's dispersal movements. This understanding is important to integrate the predator needs as natural mortality of its prey in models to set prey catch limits for fisheries. Reliable estimates of the variability of these needs are essential for a precautionary interpretation in the context of an ecosystem-based management.

Digital PCR on an integrated self-priming compartmentalization chip.

PubMed

Zhu, Qiangyuan; Qiu, Lin; Yu, Bingwen; Xu, Yanan; Gao, Yibo; Pan, Tingting; Tian, Qingchang; Song, Qi; Jin, Wei; Jin, Qinhan; Mu, Ying

2014-03-21

An integrated on-chip valve-free and power-free microfluidic digital PCR device is for the first time developed by making use of a novel self-priming compartmentalization and simple dehydration control to realize 'divide and conquer' for single DNA molecule detection. The high gas solubility of PDMS is exploited to provide the built-in power of self-priming so that the sample and oil are sequentially sucked into the device to realize sample self-compartmentalization based on surface tension. The lifespan of its self-priming capability was about two weeks tested using an air-tight packaging bottle sealed with a small amount of petroleum jelly, which is significant for a practical platform. The SPC chip contains 5120 independent 5 nL microchambers, allowing the samples to be compartmentalized completely. Using this platform, three different abundances of lung cancer related genes are detected to demonstrate the feasibility and flexibility of the microchip for amplifying a single nucleic acid molecule. For maximal accuracy, within less than 5% of the measurement deviation, the optimal number of positive chambers is between 400 and 1250 evaluated by the Poisson distribution, which means one panel can detect an average of 480 to 4804 template molecules. This device without world-to-chip connections eliminates the constraint of the complex pipeline control, and is an integrated on-chip platform, which would be a significant improvement to digital PCR automation and more user-friendly.

Reversible thermo-pneumatic valves on centrifugal microfluidic platforms.

PubMed

Aeinehvand, Mohammad Mahdi; Ibrahim, Fatimah; Harun, Sulaiman Wadi; Kazemzadeh, Amin; Rothan, Hussin A; Yusof, Rohana; Madou, Marc

2015-08-21

Centrifugal microfluidic systems utilize a conventional spindle motor to automate parallel biochemical assays on a single microfluidic disk. The integration of complex, sequential microfluidic procedures on these platforms relies on robust valving techniques that allow for the precise control and manipulation of fluid flow. The ability of valves to consistently return to their former conditions after each actuation plays a significant role in the real-time manipulation of fluidic operations. In this paper, we introduce an active valving technique that operates based on the deflection of a latex film with the potential for real-time flow manipulation in a wide range of operational spinning speeds. The reversible thermo-pneumatic valve (RTPV) seals or reopens an inlet when a trapped air volume is heated or cooled, respectively. The RTPV is a gas-impermeable valve composed of an air chamber enclosed by a latex membrane and a specially designed liquid transition chamber that enables the efficient usage of the applied thermal energy. Inputting thermo-pneumatic (TP) energy into the air chamber deflects the membrane into the liquid transition chamber against an inlet, sealing it and thus preventing fluid flow. From this point, a centrifugal pressure higher than the induced TP pressure in the air chamber reopens the fluid pathway. The behaviour of this newly introduced reversible valving system on a microfluidic disk is studied experimentally and theoretically over a range of rotational frequencies from 700 RPM to 2500 RPM. Furthermore, adding a physical component (e.g., a hemispherical rubber element) to induce initial flow resistance shifts the operational range of rotational frequencies of the RTPV to more than 6000 RPM. An analytical solution for the cooling of a heated RTPV on a spinning disk is also presented, which highlights the need for the future development of time-programmable RTPVs. Moreover, the reversibility and gas impermeability of the RTPV in the microfluidic networks are validated on a microfluidic disk designed for performing liquid circulation. Finally, an array of RTPVs is integrated into a microfluidic cartridge to enable sequential aliquoting for the conversion of dengue virus RNA to cDNA and the preparation of PCR reaction mixtures.

Sequential Online Wellness Programming Is an Effective Strategy to Promote Behavior Change

ERIC Educational Resources Information Center

MacNab, Lindsay R.; Francis, Sarah L.

2015-01-01

The growing number of United States youth and adults categorized as overweight or obese illustrates a need for research-based family wellness interventions. Sequential, online, Extension-delivered family wellness interventions offer a time- and cost-effective approach for both participants and Extension educators. The 6-week, online Healthy…

Measuring Marbles: Demonstrating the Basic Tenets of Measurement Theory

ERIC Educational Resources Information Center

Wininger, Steven R.

2007-01-01

A hands-on activity is described in which students attempt to measure something that they cannot see. In small groups, students estimate the number of marbles in sealed boxes. Next, students' estimates are compared with the actual numbers. Last, values from both the students' estimates and actual numbers are used to explain measurement theory and…

Cost-Utility Analysis of Cochlear Implantation in Australian Adults.

PubMed

Foteff, Chris; Kennedy, Steven; Milton, Abul Hasnat; Deger, Melike; Payk, Florian; Sanderson, Georgina

2016-06-01

Sequential and simultaneous bilateral cochlear implants are emerging as appropriate treatment options for Australian adults with sensory deficits in both cochleae. Current funding of Australian public hospitals does not provide for simultaneous bilateral cochlear implantation (CI) as a separate surgical procedure. Previous cost-effectiveness studies of sequential and simultaneous bilateral CI assumed 100% of unilaterally treated patients' transition to a sequential bilateral CI. This assumption does not place cochlear implantation in the context of the generally treated population. When mutually exclusive treatment options exist, such as unilateral CI, sequential bilateral CI, and simultaneous bilateral CI, the mean costs of the treated populations are weighted in the calculation of incremental cost-utility ratios. The objective was to evaluate the cost-utility of bilateral hearing aids (HAs) compared with unilateral, sequential, and simultaneous bilateral CI in Australian adults with bilateral severe to profound sensorineural hearing loss. Cost-utility analysis of secondary sources input to a Markov model. Australian health care perspective, lifetime horizon with costs and outcomes discounted 5% annually. Bilateral HAs as treatment for bilateral severe to profound sensorineural hearing loss compared with unilateral, sequential, and simultaneous bilateral CI. Incremental costs per quality adjusted life year (AUD/QALY). When compared with bilateral hearing aids the incremental cost-utility ratio for the CI treatment population was AUD11,160/QALY. The incremental cost-utility ratio was weighted according to the number of patients treated unilaterally, sequentially, and simultaneously, as these were mutually exclusive treatment options. No peer-reviewed articles have reported the incremental analysis of cochlear implantation in a continuum of care for surgically treated populations with bilateral severe to profound sensorineural hearing loss. Unilateral, sequential, and simultaneous bilateral CI were cost-effective when compared with bilateral hearing aids. Technologies that reduce the total number of visits for a patient could introduce additional cost efficiencies into clinical practice.

Miniature electrically operated diaphragm valve

DOEpatents

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

2001-01-01

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

10 CFR 110.50 - Terms.

Code of Federal Regulations, 2011 CFR

2011-01-01

... and activity level in TBq, both for single and aggregate shipments; (E) Make, model and serial number... exporting facility; (D) Radionuclides and activity level in TBq, both for single and aggregate shipments; (E) Make, model and serial number, radionuclide, and activity level for any Category 1 and 2 sealed sources...

Ecological Risk Assessment of Perchlorate in Avian Species, Rodents, Amphibians and Fish

DTIC Science & Technology

2003-04-01

http://www .indiana.edu/- axolotl ). 10.0 JUSTIFICATION OF TEST SYSTEM Perchlorate occurs in ground and surface waters in 44 states in the USA... axolotl ). * Sequentially numbered in order of the date that the change is effective Dept. of Biological Sciences (DBS) Box 43131 Lubbock, TX 79409...KCl, 0.025 giL; CaCh2 H20, 0.65 g/L; MgS04·7H20, 0.1 giL (http://www.indiana.edu/~ axolotl ). *Sequentially numbered in order of the date that the

Impaired immune function in seals and laboratory rats exposed to dioxin-like compounds from Baltic herring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ross, P.S.; Swart, R.L. de; Timmerman, H.H.

Complex mixtures of lipophilic contaminants have been shown to affect certain top predators in the aquatic food chain, including seals. A recent demonstration that harbor seals (Phoca vitulina) fed Baltic Sea herring displayed impaired natural killer cell activity and T-lymphocyte function represented the first demonstration of immunotoxicity induced by ambient levels of contaminants in the environment. While these animals had a lower ability to respond to immunizations with inactivated vaccines, specific antibody responses, and in vitro antigen-specific lymphoproliferative responses, obvious constraints limited the ability to extend these results with host resistance tests or an evaluation of thymus and other lymphoidmore » organs. The authors therefore set up a parallel study by exposing pregnant laboratory rats to the same Baltic herring contaminant mixture as received the seals. They then examined immune function parameters and host resistance to virus infection. As in the seals, rat pups of the Baltic group had impaired T-lymphocyte function. In addition, thymus cells and/or their precursors appeared to be targeted, as their numbers and function were reduced in the rats. Following challenge with rat cytomegalovirus in a host resistance study, rat pups in the Baltic group had impaired natural killer cell responses to the virus infection, and lower specific CD8 + (cytotoxic T-lymphocyte) responses following in vitro stimulation. By extrapolation, these results suggest that the impaired immune responses observed in the Baltic group of seals may lead to a less effective defense against virus infections in marine mammals inhabiting polluted coastal waters. Toxicological profiles and results of both the captive seal and laboratory rat experiments tend to implicate the 2,3,7,8-TCDD-like PCB, dioxin and furan congeners in the immunosuppression, and point to a major role for the PCBs.« less

Safety assessment of borehole disposal of unwanted radioactive sealed sources in Egypt using Goldsim.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cochran, John Russell; Mattie, Patrick D.

2004-10-01

A radioactive sealed source is any radioactive material that is encased in a capsule designed to prevent leakage or escape of the radioactive material. Radioactive sealed sources are used for a wide variety of applications at hospitals, in manufacturing and research. Typical uses are in portable gauges to measure soil compaction and moisture or to determine physical properties of rocks units in boreholes (well logging). Hospitals and clinics use radioactive sealed sources for teletherapy and brachytherapy. Oil exploration and medicine are the largest users. Accidental mismanagement of radioactive sealed sources each year results in a large number of people receivingmore » very high or even fatal does of ionizing radiation. Deliberate mismanagement is a growing international concern. Sealed sources must be managed and disposed effectively in order to protect human health and the environment. Effective national safety and management infrastructures are prerequisites for efficient and safe transportation, treatment, storage, and disposal. The Integrated Management Program for Radioactive Sealed Sources in Egypt (IMPRSS) is a cooperative development agreement between the Egyptian Atomic Energy Authority (EAEA), Egyptian Ministry of Health (MOH), Sandia National Laboratories (SNL), the University of New Mexico (UNM), and Agriculture Cooperative Development International (ACDI/VOCA). The EAEA, teaming with SNL, is conducting a Preliminary Safety Assessment (PSA) of an intermediate-depth borehole disposal in thick arid alluvium in Egypt based on experience with the U.S. Greater Confinement Disposal (GCD). Goldsim has been selected for the preliminary disposal system assessment for the Egyptian GCD Study. The results of the PSA will then be used to decide if Egypt desires to implement such a disposal system.« less

Acoustic survey for marine mammal occurrence and distribution off East Antarctica (30-80°E) in January-February 2006

NASA Astrophysics Data System (ADS)

Gedamke, Jason; Robinson, Sarah M.

2010-05-01

A large scale, systematic, acoustic survey for whales and seals in eastern Antarctic waters was conducted in January-February 2006. During the BROKE-West survey of Southern Ocean waters between 30 and 80° E longitude, an acoustic survey was conducted to complement a traditional visual survey for marine mammal occurrence and distribution. As part of the survey, 145 DIFAR sonobuoys were deployed every 30' of latitude on north-south transects, and prior to CTD stations on the initial east-west transect. Underwater sound was analyzed for 70 minute samples from each sonobuoy. Blue whales were the most commonly recorded species, identified at 55 of the sonobuoy deployment sites. Other species recorded include: sperm (46 sites), fin (14), humpback (2), and sei (3) whales, and leopard (11) and Ross (17) seals. Large numbers of blue and sperm whales, and all Ross seals were detected on the westernmost two transects, which were the only transects of the survey with relatively extensive sea ice remaining off the continental shelf. Large numbers of blue whales were also detected in the more eastern waters of the survey off the Prydz Bay region, while two detections of pygmy blue whales represent the farthest south these whales have been recorded. Of the relatively few fin whale detections, most occurred in more northerly waters. Fin whale vocalizations from this region were distinctly different than those recorded elsewhere around Antarctica suggesting acoustic recordings may be useful to delineate regional or stock boundaries of this species. Previously undescribed sounds were attributed to Ross seals. Acoustic detections of these and leopard seal sounds indicate these animals venture further from their traditionally described distributions, with vocalizing leopard seals occurring much further north than might be expected. Overall, the results of the sonobuoy survey provide a measure of each species' relative spatial distribution over the survey area based on acoustic detections, and when combined with the results of the visual survey, will provide a comprehensive view of marine mammal distribution throughout the region during the BROKE-West survey.

Dampers for Stationary Labyrinth Seals

NASA Technical Reports Server (NTRS)

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 0.062 in. (0.8 to 1.6 millimeters) at fill levels of from 70 to 95 percent.

Symptoms prevalence among office workers of a sealed versus a non-sealed building: associations to indoor air quality.

PubMed

Rios, José Luiz de Magalhães; Boechat, José Laerte; Gioda, Adriana; dos Santos, Celeste Yara; de Aquino Neto, Francisco Radler; Lapa e Silva, José Roberto

2009-11-01

An increasing number of complaints related to time spent in artificially ventilated buildings have been progressively reported and attributed, at least in part, to physical and chemical exposures in the office environment. The objective of this research was to investigate the association between the prevalence of work-related symptoms and the indoor air quality, comparing a sealed office building with a naturally ventilated one, considering, specially, the indoor concentration of TPM, TVOCs and the main individual VOCs. A cross-sectional study was performed to compare the prevalence of sick building syndrome (SBS) symptoms among 1736 office workers of a sealed office building and 950 of a non-sealed one, both in Rio de Janeiro's downtown. The prevalence of symptoms was obtained by a SBS standardized questionnaire. The IAQ of the buildings was evaluated through specific methods, to determine the temperature, humidity, particulate matter and volatile organic compound (VOC) concentrations. Upper airways and ophthalmic symptoms, tiredness and headache were highly prevalent in both buildings. Some symptoms were more prevalent in the sealed building: "eye dryness" 33.3% and 27.1% (p: 0.01); "runny nose" 37.3% and 31.3% (p: 0.03); "dry throat" 42% and 36% (p: 0.02); and "lethargy" 58.5% and 50.5% (p: 0.03) respectively. However, relative humidity and indoor total particulate matter (TPM) concentration as well as total volatile organic compounds (TVOCs) were paradoxically greater in the non-sealed building, in which aromatic compounds had higher concentration, especially benzene. The analysis between measured exposure levels and resulting symptoms showed no association among its prevalence and TPM, TVOCs, benzene or toluene concentration in none of the buildings. Other disregarded factors, like undetected VOCs, mites, molds and endotoxin concentrations, may be associated to the greater prevalence of symptoms in the sealed building.

[Topical hemostatic devices in surgery: between science and marketing].

PubMed

González, Héctor Daniel; Figueras Felip, Joan

2009-06-01

Topical hemostatic agents have been used in surgery with varying degrees of success. These agents include oxidized cellulose, absorbable gelatin sponges, microfibrillar collagen and fibrin seals. Fibrin seals have become widely used as they improve perioperative hemostasis, reduce the need for red blood cell transfusions and prevent biliary leaks. Their widespread use, however, contrasts with the scarcity of data from controlled studies to support their clinical effectiveness. Therefore, a prospective, randomized, controlled, single-center study was performed in 300 patients who underwent elective hepatectomy, with and without application of fibrin seal on the raw liver surface. None of the variables evaluated (blood loss, transfusions, biliary fistulas and postoperative results) differed between the two groups. We conclude that the application of fibrin seal does not seem justified and that discontinuing its routine use would substantially reduce costs. The use of a new agent, Tachosil, is supported by a single multicenter, prospective, randomized, controlled trial, which is limited by the small number of patients and by the fact that the variable analyzed--time from application to hemostasis--may not be clinically relevant.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Pin; Wang, Yifeng; Rodriguez, Mark A.

The concept of deep borehole nuclear waste disposal has recently been proposed. Effective sealing of a borehole after waste emplacement is generally required. In a high temperature disposal mode, the sealing function will be fulfilled by melting the ambient granitic rock with waste decay heat or an external heating source, creating a melt that will encapsulate waste containers or plug a portion of the borehole above a stack of the containers. However, there are certain drawbacks associated with natural materials, such as high melting temperatures, slow crystallization kinetics, the resulting sealing materials generally being porous with low mechanical strength, insufficientmore » adhesion to waste container surface, and lack of flexibility for engineering controls. Here we show that natural granitic materials can be purposefully engineered through chemical modifications to enhance the sealing capability of the materials for deep borehole disposal. This work systematically explores the effect of chemical modification and crystallinity (amorphous vs. crystalline) on the melting and crystallization processes of a granitic rock system. A number of engineered granitic materials have been obtained that have decreased melting points, enhanced viscous densification, and accelerated recrystallization rates without compromising the mechanical integrity of the materials.« less

Fractional capacity electrolyzer development for CO2 and H2O electrolysis

NASA Technical Reports Server (NTRS)

Wynveen, R. A.

1980-01-01

The electrolyzer module was designed to produce 0.24 kg/d (0.53 lb/d) of breathable oxygen from the electrolysis of metabolic carbon dioxide and water vapor. The fractional capacity electrolyzer module is constructed from three electrochemical tube cells and contains only three critical seals. The module design illustrated an 84 percent reduction in the total number of seals for a one person capacity oxygen generating system based on the solid electrolyte carbon dioxide and water vapor electrolysis concept. The electrolyzer module was successfully endurance tested for 71 days.

Surface Roughness: Its Effects on the Performance of a Two-Dimensional Compressor Cascade.

DTIC Science & Technology

1986-12-01

Outside air was dLawn into a sealed containment room where the option existed to mix it with recirculated warmer room air in order to stabilize the...by " applying different grades of carborundum grit to the surface and sealing them in place with an acrylic adhesive. This procedure had a number of...U. at the Ong" start of the loop . If it was different, the process was re- -38- peated with the new value until such time the new and old U Is were

Electrode array for neural stimulation

DOEpatents

Wessendorf, Kurt O [Albuquerque, NM; Okandan, Murat [Edgewood, NM; Stein, David J [Albuquerque, NM; Yang, Pin [Albuquerque, NM; Cesarano, III, Joseph; Dellinger, Jennifer [Albuquerque, NM

2011-08-16

An electrode array for neural stimulation is disclosed which has particular applications for use in a retinal prosthesis. The electrode array can be formed as a hermetically-sealed two-part ceramic package which includes an electronic circuit such as a demultiplexer circuit encapsulated therein. A relatively large number (up to 1000 or more) of individually-addressable electrodes are provided on a curved surface of a ceramic base portion the electrode array, while a much smaller number of electrical connections are provided on a ceramic lid of the electrode array. The base and lid can be attached using a metal-to-metal seal formed by laser brazing. Electrical connections to the electrode array can be provided by a flexible ribbon cable which can also be used to secure the electrode array in place.

HSR Overview

NASA Technical Reports Server (NTRS)

Hendricks, R. C.; Steinetz, B. M.

2006-01-01

The leading Aeronautics program within NASA is the High Speed Research Program (HSR). The HSR program's highest priorities are high pay-off technologies for airframe and propulsion systems required for a high speed civil transport (HSCT). These priorities have been developed collaboratively with NASA, FAA and the US Industry (Boeing-McDonnell Douglas, Pratt & Whitney and General Electric). Phase one of the HSR program started on 1990, and concentrated on the environmental challenges of minimizing NOx and noise. The first program goal is to reduce the NOx emission index to less than 5 (Concord NOx index is 20 and is unacceptable), in order to have little impact on the earth's ozone layer. The second goal is to reduce noise levels to FAR Stage 3 (or better), comparable to those of subsonic aircraft (far below the Concorde noise levels that require exemptions form less stringent standards). This requirement greatly impacts the nozzle design increasing its length and complexity and poses unique sealing challenges. Phase two started in 1993 and initiated work on the technologies required for an economical HSCT. Materials technologies under development include a ceramic-matrix-composite combustion liner, lightweight materials for the nozzle, as well long-life turbomachinery disk and blade alloys. Other required materials are being developed under the DOD-IHPTET program, where there is close cooperation. Economic goals translate into the development of technologies for tri-class service, 5000 nautical mile range aircraft with a ticket price no more than 20% over the subsonic ticket price. The potential market could be as large as 1500 aircraft, according to a Boeing study. Technology alone will not enable this airplane, yet without enabling technologies "on the shelf", it will not occur. The HSCT engine will be the largest engine ever built and operate at maximum conditions for long periods of time posing a number of challenges. The HSR engine mission requires that rotating equipment stay at take-off condition temperatures for hours not minutes per flight. Hence rotating equipment and seals must operate for many thousands of hours at extreme temperatures. It is anticipated that the nozzle will be 12 feet long and roughly 4 ft. by 5 ft. in cross-section with a nominal airflow of 800 lbs/sec. The complex function of the nozzle (including an ejector for noise attenuation) combined with long life place new demands on nozzle seal design. Three inlet configurations are under consideration with attendant sealing challenges, as will be illustrated herein. Four of these engines are required to propel a 5000 nautical mile class vehicle which demand that component reliability be at the highest possible level. In response, an HSR seals session was implemented as a part of the 1997-Seals and Secondary Flow Workshop. Overview presentations were given for each of the following areas: inlet, turbomachinery, combustor and nozzle. The HSCT seal issues center on durability and efficiency of rotating equipment seals (including brush seals), structural seals (including rope seals and other advanced concepts), and high-speed bearing and sump seals. Tighter clearances, propulsion system size and thermal requirements represent extremes that challenge the component designers. This document provides an initial step toward defining HSR seal needs. The overview for HSR seal designs includes, defining seal objectives, summarizing sealing and materials requirements, presenting relevant seal cross-sections, and identifying technology needs for the HSR office.

Students' conceptual performance on synthesis physics problems with varying mathematical complexity

NASA Astrophysics Data System (ADS)

Ibrahim, Bashirah; Ding, Lin; Heckler, Andrew F.; White, Daniel R.; Badeau, Ryan

2017-06-01

A body of research on physics problem solving has focused on single-concept problems. In this study we use "synthesis problems" that involve multiple concepts typically taught in different chapters. We use two types of synthesis problems, sequential and simultaneous synthesis tasks. Sequential problems require a consecutive application of fundamental principles, and simultaneous problems require a concurrent application of pertinent concepts. We explore students' conceptual performance when they solve quantitative synthesis problems with varying mathematical complexity. Conceptual performance refers to the identification, follow-up, and correct application of the pertinent concepts. Mathematical complexity is determined by the type and the number of equations to be manipulated concurrently due to the number of unknowns in each equation. Data were collected from written tasks and individual interviews administered to physics major students (N =179 ) enrolled in a second year mechanics course. The results indicate that mathematical complexity does not impact students' conceptual performance on the sequential tasks. In contrast, for the simultaneous problems, mathematical complexity negatively influences the students' conceptual performance. This difference may be explained by the students' familiarity with and confidence in particular concepts coupled with cognitive load associated with manipulating complex quantitative equations. Another explanation pertains to the type of synthesis problems, either sequential or simultaneous task. The students split the situation presented in the sequential synthesis tasks into segments but treated the situation in the simultaneous synthesis tasks as a single event.

Mining of high utility-probability sequential patterns from uncertain databases

PubMed Central

Zhang, Binbin; Fournier-Viger, Philippe; Li, Ting

2017-01-01

High-utility sequential pattern mining (HUSPM) has become an important issue in the field of data mining. Several HUSPM algorithms have been designed to mine high-utility sequential patterns (HUPSPs). They have been applied in several real-life situations such as for consumer behavior analysis and event detection in sensor networks. Nonetheless, most studies on HUSPM have focused on mining HUPSPs in precise data. But in real-life, uncertainty is an important factor as data is collected using various types of sensors that are more or less accurate. Hence, data collected in a real-life database can be annotated with existing probabilities. This paper presents a novel pattern mining framework called high utility-probability sequential pattern mining (HUPSPM) for mining high utility-probability sequential patterns (HUPSPs) in uncertain sequence databases. A baseline algorithm with three optional pruning strategies is presented to mine HUPSPs. Moroever, to speed up the mining process, a projection mechanism is designed to create a database projection for each processed sequence, which is smaller than the original database. Thus, the number of unpromising candidates can be greatly reduced, as well as the execution time for mining HUPSPs. Substantial experiments both on real-life and synthetic datasets show that the designed algorithm performs well in terms of runtime, number of candidates, memory usage, and scalability for different minimum utility and minimum probability thresholds. PMID:28742847

Enhancing lineup identification accuracy: two codes are better than one.

PubMed

Melara, R D; DeWitt-Rickards, T S; O'Brien, T P

1989-10-01

Ways of improving identification accuracy were explored by comparing the conventional visual lineup with an auditory/visual lineup, one that paired color photographs with voice recordings. This bimodal lineup necessitated sequential presentation of lineup members; Experiment 1 showed that performance in sequential lineups was better than performance in traditional simultaneous lineups. In Experiments 2A and 2B unimodal and bimodal lineups were compared by using a multiple-lineup paradigm: Ss viewed 3 videotaped episodes depicting standard police procedures and were tested in 4 sequential lineups. Bimodal lineups were more diagnostic than either visual or auditory lineups alone. The bimodal lineup led to a 126% improvement in number of correct identifications over the conventional visual lineup, with no concomitant increase in number of false identifications. These results imply strongly that bimodal procedures should be adopted in real-world lineups. The nature of memorial processes underlying this bimodal advantage is discussed.

NASA DOE POD NDE Capabilities Data Book

NASA Technical Reports Server (NTRS)

Generazio, Edward R.

2015-01-01

This data book contains the Directed Design of Experiments for Validating Probability of Detection (POD) Capability of NDE Systems (DOEPOD) analyses of the nondestructive inspection data presented in the NTIAC, Nondestructive Evaluation (NDE) Capabilities Data Book, 3rd ed., NTIAC DB-97-02. DOEPOD is designed as a decision support system to validate inspection system, personnel, and protocol demonstrating 0.90 POD with 95% confidence at critical flaw sizes, a90/95. The test methodology used in DOEPOD is based on the field of statistical sequential analysis founded by Abraham Wald. Sequential analysis is a method of statistical inference whose characteristic feature is that the number of observations required by the procedure is not determined in advance of the experiment. The decision to terminate the experiment depends, at each stage, on the results of the observations previously made. A merit of the sequential method, as applied to testing statistical hypotheses, is that test procedures can be constructed which require, on average, a substantially smaller number of observations than equally reliable test procedures based on a predetermined number of observations.

Seals Having Textured Portions for Protection in Space Environments

NASA Technical Reports Server (NTRS)

Daniels, Christopher (Inventor); Garafolo, Nicholas (Inventor)

2016-01-01

A sealing construct for a space environment includes a seal-bearing object, a seal on the seal-bearing object, and a seal-engaging object. The seal includes a seal body having a sealing surface, and a textured pattern at the sealing surface, the textured pattern defining at least one shaded channel surface. The seal-engaging object is selectively engaged with the seal-bearing object through the seal. The seal-engaging object has a sealing surface, wherein, when the seal-engaging object is selectively engaged with the seal-bearing object, the sealing surface of the seal-engaging object engages the sealing surface of the seal, and the seal is compressed between the seal-bearing object and the seal-engaging object such that at least one shaded channel surface engages the sealing surface of the seal-engaging object.

Dialysis: Deciding to Stop

MedlinePlus

... Names, addresses and telephone numbers of your attorney, accountant, family members and other loved ones, friends and ... Wise Giving Alliance Charity Seal provides the giving public with an easily recognizable symbol which certifies that ...

Serologic evidence of Brucella infection in pinnipeds along the coast of Hokkaido, the northernmost main island of Japan.

PubMed

Abe, Erika; Ohishi, Kazue; Ishinazaka, Tsuyoshi; Fujii, Kei; Maruyama, Tadashi

2017-04-01

Brucella infection in Hokkaido was serologically surveyed in four species of pinnipeds inhabiting Cape Erimo during 2008-2013 and the Shiretoko Peninsula in 1999 by ELISA using Brucella abortus and B. canis as antigens. Anti-Brucella positive sera showed higher absorbance to B. abortus than B. canis in almost all samples. Anti-B. abortus antibodies were detected in serum samples from 24% (n = 55) of Western Pacific harbor seals (Phoca vitulina stejnegeri) in Cape Erimo and from 66% (n = 41) of spotted seals (P. largha), 15% (n = 20) of ribbon seals (Histriophoca fasciata) and 18% (n = 17) of Western Steller's sea lions (Eumetopias jubatus jubatus) in the Shiretoko Peninsula. Anti-Brucella antibodies were detected at higher absorbance in 1- to 4-year-old harbor seals than in the pups and mature animals, suggesting either that Brucella infection mainly occurs after weaning or that it is maternally transmitted to pups with premature or suppressed immunity. Anti-Brucella antibodies were detected in both immature and mature spotted seals and ribbon seals, with higher absorbance in the former. The antibodies were detected only in mature Western Steller's sea lions. Western blot analysis of the serum samples showed some differences in band appearances, namely discrete versus smeary, and in the number of bands, indicating that multiple different Brucella may be prevalent in pinnipeds in Hokkaido. Alternatively, the Brucella of pinnipeds may have some intra-species diversity. © 2017 The Societies and John Wiley & Sons Australia, Ltd.

The Integration of Study and Work-Integrated Learning Experience through the Sequential, Embedded Completion of Tertiary Qualifications

ERIC Educational Resources Information Center

Whannell, Patricia; Humphries, Judy; Whannell, Robert; Usher, Kim

2015-01-01

A number of different models have been developed to integrate both Vocational Education and Training (VET) and university study with a view to producing work-ready graduates. This paper describes one joint initiative which allows students to integrate their theoretical study and work-integrated learning (WIL) experience by supporting a sequential,…

Comparative efficacy of simultaneous versus sequential multiple health behavior change interventions among adults: A systematic review of randomised trials.

PubMed

James, Erica; Freund, Megan; Booth, Angela; Duncan, Mitch J; Johnson, Natalie; Short, Camille E; Wolfenden, Luke; Stacey, Fiona G; Kay-Lambkin, Frances; Vandelanotte, Corneel

2016-08-01

Growing evidence points to the benefits of addressing multiple health behaviors rather than single behaviors. This review evaluates the relative effectiveness of simultaneous and sequentially delivered multiple health behavior change (MHBC) interventions. Secondary aims were to identify: a) the most effective spacing of sequentially delivered components; b) differences in efficacy of MHBC interventions for adoption/cessation behaviors and lifestyle/addictive behaviors, and; c) differences in trial retention between simultaneously and sequentially delivered interventions. MHBC intervention trials published up to October 2015 were identified through a systematic search. Eligible trials were randomised controlled trials that directly compared simultaneous and sequential delivery of a MHBC intervention. A narrative synthesis was undertaken. Six trials met the inclusion criteria and across these trials the behaviors targeted were smoking, diet, physical activity, and alcohol consumption. Three trials reported a difference in intervention effect between a sequential and simultaneous approach in at least one behavioral outcome. Of these, two trials favoured a sequential approach on smoking. One trial favoured a simultaneous approach on fat intake. There was no difference in retention between sequential and simultaneous approaches. There is limited evidence regarding the relative effectiveness of sequential and simultaneous approaches. Given only three of the six trials observed a difference in intervention effectiveness for one health behavior outcome, and the relatively consistent finding that the sequential and simultaneous approaches were more effective than a usual/minimal care control condition, it appears that both approaches should be considered equally efficacious. PROSPERO registration number: CRD42015027876. Copyright © 2016 Elsevier Inc. All rights reserved.

ChIP-re-ChIP: Co-occupancy Analysis by Sequential Chromatin Immunoprecipitation.

PubMed

Beischlag, Timothy V; Prefontaine, Gratien G; Hankinson, Oliver

2018-01-01

Chromatin immunoprecipitation (ChIP) exploits the specific interactions between DNA and DNA-associated proteins. It can be used to examine a wide range of experimental parameters. A number of proteins bound at the same genomic location can identify a multi-protein chromatin complex where several proteins work together to regulate gene transcription or chromatin configuration. In many instances, this can be achieved using sequential ChIP; or simply, ChIP-re-ChIP. Whether it is for the examination of specific transcriptional or epigenetic regulators, or for the identification of cistromes, the ability to perform a sequential ChIP adds a higher level of power and definition to these analyses. In this chapter, we describe a simple and reliable method for the sequential ChIP assay.

Three-Dimensional Modeling of the Reactive Transport of CO2 and Its Impact on Geomechanical Properties of Reservoir Rocks and Seals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nguyen, Ba Nghiep; Hou, Zhangshuan; Bacon, Diana H.

This article develops a novel multiscale modeling approach to analyze CO2 reservoirs using Pacific Northwest National Laboratory’s STOMP-CO2-R code that is interfaced with the ABAQUS® finite element package. The STOMP-CO2-R/ABAQUS® sequentially coupled simulator accounts for the reactive transport of CO2 causing mineral composition changes that modify the geomechanical properties of reservoir rocks and seals. Formation rocks’ elastic properties that vary during CO2 injection and govern the poroelastic behavior of rocks are modeled by an Eshelby-Mori-Tanka approach (EMTA) implemented in ABAQUS® via user-subroutines. The computational tool incorporates the change in rock permeability due to both geochemistry and geomechanics. A three-dimensional (3D)more » STOMP-CO2-R model for a model CO2 reservoir containing a vertical fault is built to analyze a formation containing a realistic geochemical reaction network with 5 minerals: albite, anorthite, calcite, kaolinite and quartz. A 3D ABAQUS® model that maps the above STOMP-CO2-R model is built for the analysis using STOMP-CO2-R/ABAQUS®. The results show that the changes in volume fraction of minerals include dissolution of anorthite, precipitation of calcite and kaolinite, with little change in the albite volume fraction. After a long period of CO2 injection the mineralogical and geomechanical changes significantly reduced the permeability and elastic modulus of the reservoir (between the base and caprock) in front of the fault leading to a reduction of the pressure margin to fracture at and beyond the injection location. The impact of reactive transport of CO2 on the geomechanical properties of reservoir rocks and seals are studied in terms of mineral composition changes that directly affect the rock stiffness, stress and strain distributions as well as the pressure margin to fracture.« less

White Sea's Severe Winter Hydrological Hazard and Its Effect On Decrease of Population of Greenland Seals (1998/99 Winter Ecological Catastrophe)

NASA Astrophysics Data System (ADS)

Melentyev, Konstantin V.; Chernook, Vladimir I.

Types of hydrological hazards are various but its agencies are especially diversified . At this study hazard effects will be assessed for White Sea population of Greenland seals - a representatives of high level of marine fodder chains and the prime part of the Arctic nature. Number of population and type of their migration are strongly depended from different meteorological and hydrological parameters and processes, climate change and anthropogenical press, including pollution and fur-seal fishery, create additional problems. Especially hard situation happens now with the ice- associated sea mammals (p olar bear, seal, walrus, etc.). Mass destruction of seals in the White Sea (ecological catastrophe) which happens periodically is close connected with different kind of meteorological and hydrological hazard. Greenland seals selected these water areas for whelping where a rookeries are organized on pack ice. But severe winter conditions (long-run severe frosts and NE winds) can modify ice regime of the White Sea which lead to effect "blocking" of pack ice (and whelping rookeries) inside the "Basin". These features stimulated strong reduction number ofseals (especially pups). Marine biology use modelling of the system "sea mammal-media", study "behavior factors" and mammals biodiversity at the different natural conditions. But the main critical goal is the development of special observational network for the White Sea and contiguous regions. A contemporary technologies assume integration of remote sensing and in situ hydro-chemical measurements. Airborne IR and visible observation of the marginal Arctic seas became now an indispensable part of marine ecological investigations. Application of satellite data for monitoring of sea mammals has been attractive also but practical use is restrained by its small spatial resolution, daytime illumination and cloud influence in the Arctic. Launching ERS synthetic aperture radar (SAR) in 1991, which provides global all- weather soundig with resolution 20-25 m, changed situation. High transparency of snow and relatively deep penetration of signals in ice is basis of sub-surface sounding. SAR images allow fix documentary different ice parameters: development and arrangement, ice type, shape of floes, ice concentration and compactness. Unfortunately time being resolution couldn't resolve individual sea mammal. In order to investigate the ice regime, estimate number of seals at the different winter conditions and forecast the future tendency of population decrease we perform regularly ice reconnaissance. Accomplish these observations and computations more precisely could be done at the time of mass accumulation of seals, that is whelping and moulting period. Aerial inspection is difficult task: weather conditions and masking coloration obstructs the problems, sometimes mammals couldn't be quite founded. Comprehensive study of ERS SAR signatures for diagnosis type of winter hydrology of the Arctic seas and ice conditions produced by severe winter , assessment of possibility forecast of future development of ice and studying ice as non-biotic factor of ecology of Pagophilus groenladicus and other ice-associated forms of sea mammals is a new interdisciplinary approach in marine biology. First experience of such application SAR data for diagnosis of hydrological hazard produced by severe winter has been undertaken in the White Sea and contiguous seas in 1996. Sub-satellite experiments onboard nuclear icebreaker "Taymir" provided validation program, ice cores and water samples were gathered and evaluated using chemi-luminiscent methods in connection with seal' behavior patterns. Since then aircraft Antonov-26 «Arktika» provided ice and seals investigations systematically. Helicopter is employed for in situ observations, ice cores and water samples are investigated in laboratory for measurement of different pollutant , dissolved organic matter and other hydro-chemical and radio-physical paramet ers. European Space Agency (ESA) supported this work in 1998-2000. Results of comprehensive study of hydrological hazard and ecological catastrophe in the White Sea produced by 1998/99 severe winter season are demonstrated. Satellite diagnostic and situation forecast is fulfilled for the different winter severity: results of airborne charting of seals are compared for the different ice and weather conditions . 1999/2000 winter is analyzed as mean-climatic winter season.

33 CFR 168.40 - Applicable waters and number of escort vessels.

Code of Federal Regulations, 2010 CFR

2010-07-01

... a line drawn from Cape Hinchinbrook Light, to Seal Rocks Light, to a point on Montague Island at 60... waters and number of escort vessels. The requirements of this part apply to the following waters: (a... vessels in those navigable waters of the United States within Prince William Sound, Alaska, and the...

7 CFR 1499.9 - Damage to or loss of commodities.

Code of Federal Regulations, 2013 CFR

2013-01-01

... the cargo; and (6) And the damage or loss occurred with respect to a container shipment, if the... engage the services of an independent cargo surveyor to list the container numbers and seal numbers shown... or the participant engages the services of an independent cargo surveyor, the surveyor will provide...

7 CFR 1499.9 - Damage to or loss of commodities.

Code of Federal Regulations, 2014 CFR

2014-01-01

... the cargo; and (6) And the damage or loss occurred with respect to a container shipment, if the... engage the services of an independent cargo surveyor to list the container numbers and seal numbers shown... or the participant engages the services of an independent cargo surveyor, the surveyor will provide...

7 CFR 1499.9 - Damage to or loss of commodities.

Code of Federal Regulations, 2012 CFR

2012-01-01

... the cargo; and (6) And the damage or loss occurred with respect to a container shipment, if the... engage the services of an independent cargo surveyor to list the container numbers and seal numbers shown... or the participant engages the services of an independent cargo surveyor, the surveyor will provide...

10 CFR 39.15 - Agreement with well owner or operator.

Code of Federal Regulations, 2010 CFR

2010-01-01

... sealed source becomes lodged in the well, a reasonable effort will be made to recover it. (2) A person... identification plaque, constructed of long lasting material such as stainless steel, brass, bronze, or monel... appropriate; (E) The well name and well identification number(s) or other designation; (F) An identification...

10 CFR 39.15 - Agreement with well owner or operator.

Code of Federal Regulations, 2011 CFR

2011-01-01

... sealed source becomes lodged in the well, a reasonable effort will be made to recover it. (2) A person... identification plaque, constructed of long lasting material such as stainless steel, brass, bronze, or monel... appropriate; (E) The well name and well identification number(s) or other designation; (F) An identification...

Timber sale value as a function of sale characteristics and number of bidders

Treesearch

Paul E. Sendak; Paul E. Sendak

1991-01-01

Examines the effect of sale characteristics and number of bidders on sale value for timber sold by sealed-bid auction on the Green Mountain National Forest in Vermont. As anticipated from theory and previous empirical studies, increasing the number of bidders tended to increase the winning-bid value for the timber auctions studied. Efforts made to ensure that a timber...

High speed corner and gap-seal computations using an LU-SGS scheme

NASA Technical Reports Server (NTRS)

Coirier, William J.

1989-01-01

The hybrid Lower-Upper Symmetric Gauss-Seidel (LU-SGS) algorithm was added to a widely used series of 2D/3D Euler/Navier-Stokes solvers and was demonstrated for a particular class of high-speed flows. A limited study was conducted to compare the hybrid LU-SGS for approximate Newton iteration and diagonalized Beam-Warming (DBW) schemes on a work and convergence history basis. The hybrid LU-SGS algorithm is more efficient and easier to implement than the DBW scheme originally present in the code for the cases considered. The code was validated for the hypersonic flow through two mutually perpendicular flat plates and then used to investigate the flow field in and around a simplified scramjet module gap seal configuration. Due to the similarities, the gap seal flow was compared to hypersonic corner flow at the same freestream conditions and Reynolds number.

Research on the injectors remanufacturing

NASA Astrophysics Data System (ADS)

Daraba, D.; Alexandrescu, I. M.; Daraba, C.

2017-05-01

During the remanufacturing process, the injector body - after disassembling and cleaning process - should be subjected to some strict control processes, both visually and by an electronic microscope, for evidencing any defects that may occur on the sealing surface of the injector body and the atomizer. In this paper we present the path followed by an injector body in the process of remanufacturing, exemplifying the verification method of roughness and hardness of the sealing surfaces, as well as the microscopic analysis of the sealing surface areas around the inlet. These checks can indicate which path the injector body has to follow during the remanufacturing. The control methodology of the injector body, that is established on the basis of this research, helps preventing some defective injector bodies to enter into the remanufacturing process, thus reducing to a minimum the number of remanufactured injectors to be declared non-conforming after final verification process.

Seeds in space experiment results

NASA Technical Reports Server (NTRS)

Alston, Jim A.

1991-01-01

Two million seeds of 120 different varieties representing 106 species, 97 genera, and 55 plant families were flown aboard the Long Duration Exposure Facility (LDEF). The seeds were housed on the space exposed experiment developed for students (SEEDS) tray in sealed canister number six and in two small vented canisters. The tray was in the F-2 position. The seeds were germinated and the germination rates and development of the resulting plants compared to the control seed that stayed in Park Seed's seed storage facility. The initial results are presented. There was a better survival rate in the sealed canister in space than in the storage facility at Park Seed. At least some of the seeds in each of the vented canisters survived the exposure to vacuum for almost six years. The number of observed apparent mutations was very low.

Concurrent Learning of Control in Multi agent Sequential Decision Tasks

DTIC Science & Technology

2018-04-17

Concurrent Learning of Control in Multi-agent Sequential Decision Tasks The overall objective of this project was to develop multi-agent reinforcement...learning (MARL) approaches for intelligent agents to autonomously learn distributed control policies in decentral- ized partially observable...shall be subject to any oenalty for failing to comply with a collection of information if it does not display a currently valid OMB control number

Efficient sequential and parallel algorithms for record linkage.

PubMed

Mamun, Abdullah-Al; Mi, Tian; Aseltine, Robert; Rajasekaran, Sanguthevar

2014-01-01

Integrating data from multiple sources is a crucial and challenging problem. Even though there exist numerous algorithms for record linkage or deduplication, they suffer from either large time needs or restrictions on the number of datasets that they can integrate. In this paper we report efficient sequential and parallel algorithms for record linkage which handle any number of datasets and outperform previous algorithms. Our algorithms employ hierarchical clustering algorithms as the basis. A key idea that we use is radix sorting on certain attributes to eliminate identical records before any further processing. Another novel idea is to form a graph that links similar records and find the connected components. Our sequential and parallel algorithms have been tested on a real dataset of 1,083,878 records and synthetic datasets ranging in size from 50,000 to 9,000,000 records. Our sequential algorithm runs at least two times faster, for any dataset, than the previous best-known algorithm, the two-phase algorithm using faster computation of the edit distance (TPA (FCED)). The speedups obtained by our parallel algorithm are almost linear. For example, we get a speedup of 7.5 with 8 cores (residing in a single node), 14.1 with 16 cores (residing in two nodes), and 26.4 with 32 cores (residing in four nodes). We have compared the performance of our sequential algorithm with TPA (FCED) and found that our algorithm outperforms the previous one. The accuracy is the same as that of this previous best-known algorithm.

Thermal Barriers Developed for Solid Rocket Motor Nozzle Joints

NASA Technical Reports Server (NTRS)

Steinetz, Bruce M.; Dunlap, Patrick H., Jr.

2000-01-01

Space shuttle solid rocket motor case assembly joints are sealed with conventional O-ring seals that are shielded from 5500 F combustion gases by thick layers of insulation and by special joint-fill compounds that fill assembly splitlines in the insulation. On a number of occasions, NASA has observed hot gas penetration through defects in the joint-fill compound of several of the rocket nozzle assembly joints. In the current nozzle-to-case joint, NASA has observed penetration of hot combustion gases through the joint-fill compound to the inboard wiper O-ring in one out of seven motors. Although this condition does not threaten motor safety, evidence of hot gas penetration to the wiper O-ring results in extensive reviews before resuming flight. The solid rocket motor manufacturer (Thiokol) approached the NASA Glenn Research Center at Lewis Field about the possibility of applying Glenn's braided fiber preform seal as a thermal barrier to protect the O-ring seals. Glenn and Thiokol are working to improve the nozzle-to-case joint design by implementing a more reliable J-leg design and by using a braided carbon fiber thermal barrier that would resist any hot gases that the J-leg does not block.

Automated assembling of single fuel cell units for use in a fuel cell stack

NASA Astrophysics Data System (ADS)

Jalba, C. K.; Muminovic, A.; Barz, C.; Nasui, V.

2017-05-01

The manufacturing of PEMFC stacks (POLYMER ELEKTROLYT MEMBRAN Fuel Cell) is nowadays still done by hand. Over hundreds of identical single components have to be placed accurate together for the construction of a fuel cell stack. Beside logistic problems, higher total costs and disadvantages in weight the high number of components produce a higher statistic interference because of faulty erection or material defects and summation of manufacturing tolerances. The saving of costs is about 20 - 25 %. Furthermore, the total weight of the fuel cells will be reduced because of a new sealing technology. Overall a one minute cycle time has to be aimed per cell at the manufacturing of these single components. The change of the existing sealing concept to a bonded sealing is one of the important requisites to get an automated manufacturing of single cell units. One of the important steps for an automated gluing process is the checking of the glue application by using of an image processing system. After bonding the single fuel cell the sealing and electrical function can be checked, so that only functional and high qualitative cells can get into further manufacturing processes.

On-chip liquid storage and dispensing for lab-on-a-chip applications

NASA Astrophysics Data System (ADS)

Bodén, Roger; Lehto, Marcus; Margell, Joakim; Hjort, Klas; Schweitz, Jan-Åke

2008-07-01

This work presents novel components for on-chip storage and dispensing inside a lab-on-a-chip (LOC) for applications in immunoassay point-of-care testing (POCT), where incubation and washing steps are essential. It involves easy-to-use on-chip solutions for the sequential thermo-hydraulic actuation of liquids. The novel concept of combining the use of a rubber plug, both as a non-return valve cap and as a liquid injection interface of a sealed reservoir, allows simple filling of a sterilized cavity, as well as the storage and dispensing of reagent and washing buffer liquids. Segmenting the flow with air spacers enables effective rinsing and the use of small volumes of on-chip stored liquids. The chip uses low-resistance resistors as heaters in the paraffin actuator, providing the low-voltage actuation that is preferred for handheld battery driven instruments.

Fluorogenic DNA Sequencing in PDMS Microreactors

PubMed Central

Sims, Peter A.; Greenleaf, William J.; Duan, Haifeng; Xie, X. Sunney

2012-01-01

We have developed a multiplex sequencing-by-synthesis method combining terminal-phosphate labeled fluorogenic nucleotides (TPLFNs) and resealable microreactors. In the presence of phosphatase, the incorporation of a non-fluorescent TPLFN into a DNA primer by DNA polymerase results in a fluorophore. We immobilize DNA templates within polydimethylsiloxane (PDMS) microreactors, sequentially introduce one of the four identically labeled TPLFNs, seal the microreactors, allow template-directed TPLFN incorporation, and measure the signal from the fluorophores trapped in the microreactors. This workflow allows sequencing in a manner akin to pyrosequencing but without constant monitoring of each microreactor. With cycle times of <10 minutes, we demonstrate 30 base reads with ∼99% raw accuracy. “Fluorogenic pyrosequencing” combines benefits of pyrosequencing, such as rapid turn-around, native DNA generation, and single-color detection, with benefits of fluorescence-based approaches, such as highly sensitive detection and simple parallelization. PMID:21666670

Lateral thermal damage of mesoappendix and appendiceal base during laparoscopic appendectomy in children: comparison of the harmonic scalpel (Ultracision), bipolar coagulation (LigaSure), and thermal fusion technology (MiSeal).

PubMed

Pogorelić, Zenon; Katić, Josip; Mrklić, Ivana; Jerončić, Ana; Šušnjar, Tomislav; Jukić, Miro; Vilović, Katarina; Perko, Zdravko

2017-05-15

The aim of this study was to compare lateral thermal damage of mesoappendix and appendiceal base using three different instruments for sealing and cutting of mesoappendix. A total number of 99 patients (54 males and 45 females) who underwent laparoscopic appendectomy because of suspected appendicitis between December 2013 and May 2015 were enrolled in the study. The patients were divided in three groups based on instrument used for sealing of mesoappendix: group 1 (Ultracision; n = 36), group 2 (LigaSure; n = 32), and group 3 (MiSeal; n = 31). Lateral thermal damage, intraoperative and postoperative complications, duration of surgery, hospital stay, and economic value were compared within groups. The median age of patients was 14 y (range 3-17). A histopathologic analysis revealed a positive diagnosis of appendicitis in 84 patients (85%). The median lateral thermal damage on appendiceal base using Ultracision, LigaSure, and MiSeal was 0.10 mm, 0.16 mm, and 0.10 mm respectively, and on mesoappendix, 0.08 mm, 0.13 mm, and 0.08 mm, respectively. Significantly higher thermal damage was found on mesoappendix (P = 0.015) and appendiceal base (P = 0.012) in patients treated with LigaSure than in patients from other groups. There were no statistical differences among the groups regarding intraoperative and postoperative complications (P = 0.098). No significant difference in thermal damage between appendicitis and nonappendicitis group was found (P = 0.266). Using of Ultracision, LigaSure, and MiSeal for sealing of mesoappendix in laparoscopic appendectomy in children is safe and useful. LigaSure produces significantly greater lateral thermal damage compared with other instruments. Copyright © 2017 Elsevier Inc. All rights reserved.

Hole of Government: Sealing the Gap in U.S. Stability Operations

DTIC Science & Technology

2010-06-15

including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215... Gap in U.S. Stability Operations” 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR (S) Commander Patrick J...THE GAP IN U.S. STABILITY OPERATIONS by Patrick J. Hannifin CDR, USN A paper submitted to the Faculty of the Joint Advanced

Develop Efficient Leak Proof M1 Abrams Plenum Seal

DTIC Science & Technology

2014-05-07

burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching...ADDRESS. 1 . REPORT DATE (DD-MM-YYYY) 2. REPORT TYPE 3. DATES COVERED (From - To) 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c... 1 Background ................................................................................................................. 6 1.1 Problem

Second Plateau Voltage in Nickel-cadmium Cells

NASA Technical Reports Server (NTRS)

Vasanth, K. L.

1984-01-01

Sealed nickel cadmium cells having large number of cycles on them are discharged using Hg/HgO reference electrode. The negative electrode exhibits the second plateau. A SEM of negative plates of such cells show a number of large crystals of cadmium hydroxide. The large crystals on the negative plates disappear after continuous overcharging in flooded cells.

On the importance of coupled THM processes to predict the long-term response of a generic salt repository for high-level nuclear waste

NASA Astrophysics Data System (ADS)

Blanco Martin, L.; Rutqvist, J.; Birkholzer, J. T.

2013-12-01

Salt is a potential medium for the underground disposal of nuclear waste because it has several assets, in particular its ability to creep and heal fractures generated by excavation and its water and gas tightness in the undisturbed state. In this research, we focus on disposal of heat-generating nuclear waste (such as spent fuel) and we consider a generic salt repository with in-drift emplacement of waste packages and subsequent backfill of the drifts with run-of-mine crushed salt. As the natural salt creeps, the crushed salt backfill gets progressively compacted and an engineered barrier system is subsequently created. In order to evaluate the integrity of the natural and engineered barriers over the long-term, it is important to consider the coupled effects of the thermal, hydraulic and mechanical processes that take place. In particular, the results obtained so far show how the porosity reduction of the crushed salt affects the saturation and pore pressure evolution throughout the repository, both in time and space. Such compaction is induced by the stress and temperature regime within the natural salt. Also, transport properties of the host rock are modified not only by thermo-mechanically and hydraulically-induced damaged processes, but also by healing/sealing of existing fractures. In addition, the THM properties of the backfill evolve towards those of the natural salt during the compaction process. All these changes are based on dedicated laboratory experiments and on theoretical considerations [1-3]. Different scenarios are modeled and compared to evaluate the relevance of different processes from the perspective of effective nuclear waste repositories. The sensitivity of the results to some parameters, such as capillarity, is also addressed. The simulations are conducted using an updated version of the TOUGH2-FLAC3D simulator, which is based on a sequential explicit method to couple flow and geomechanics [4]. A new capability for large strains and creep has been introduced and validated. The time-dependent geomechanical response of salt is determined using the Lux/Wolters constitutive model, developed at Clausthal University of Technology (Germany). References: [1] R. Wolters, and K.-H. Lux. Evaluation of Rock Salt Barriers with Respect to Tightness: Influence of Thermomechanical Damage, Fluid Infiltration and Sealing/Healing. Proceedings of the 7th International Conference on the Mechanical Behavior of Salt (SaltMech7). Paris: Balkema, Rotterdam (2012). [2] W. Bechthold et al., Backfilling and Sealing of Underground Repositories for Radioactive Waste in Salt (BAMBUS Project), European Atomic Energy Community, Report EUR19124 EN (1999). [3] J. Kim, E.L Sonnenthal and J. Rutqvist, 'Formulation and sequential numerical algorithms of coupled fluid/heat flow and geomechanics for multiple porosity materials', Int. J. Numer. Meth. Engng., 92, 425 (2012). [4] J. Rutqvist. Status of the TOUGH-FLAC simulator and recent applications related to coupled fluid flow and crustal deformations. Computational Geosciences, 37, 739-750 (2011).

A Markov model of the Indus script

PubMed Central

Rao, Rajesh P. N.; Yadav, Nisha; Vahia, Mayank N.; Joglekar, Hrishikesh; Adhikari, R.; Mahadevan, Iravatham

2009-01-01

Although no historical information exists about the Indus civilization (flourished ca. 2600–1900 B.C.), archaeologists have uncovered about 3,800 short samples of a script that was used throughout the civilization. The script remains undeciphered, despite a large number of attempts and claimed decipherments over the past 80 years. Here, we propose the use of probabilistic models to analyze the structure of the Indus script. The goal is to reveal, through probabilistic analysis, syntactic patterns that could point the way to eventual decipherment. We illustrate the approach using a simple Markov chain model to capture sequential dependencies between signs in the Indus script. The trained model allows new sample texts to be generated, revealing recurring patterns of signs that could potentially form functional subunits of a possible underlying language. The model also provides a quantitative way of testing whether a particular string belongs to the putative language as captured by the Markov model. Application of this test to Indus seals found in Mesopotamia and other sites in West Asia reveals that the script may have been used to express different content in these regions. Finally, we show how missing, ambiguous, or unreadable signs on damaged objects can be filled in with most likely predictions from the model. Taken together, our results indicate that the Indus script exhibits rich synactic structure and the ability to represent diverse content. both of which are suggestive of a linguistic writing system rather than a nonlinguistic symbol system. PMID:19666571

Impeller leakage flow modeling for mechanical vibration control

NASA Technical Reports Server (NTRS)

Palazzolo, Alan B.

1996-01-01

HPOTP and HPFTP vibration test results have exhibited transient and steady characteristics which may be due to impeller leakage path (ILP) related forces. For example, an axial shift in the rotor could suddenly change the ILP clearances and lengths yielding dynamic coefficient and subsequent vibration changes. ILP models are more complicated than conventional-single component-annular seal models due to their radial flow component (coriolis and centrifugal acceleration), complex geometry (axial/radial clearance coupling), internal boundary (transition) flow conditions between mechanical components along the ILP and longer length, requiring moment as well as force coefficients. Flow coupling between mechanical components results from mass and energy conservation applied at their interfaces. Typical components along the ILP include an inlet seal, curved shroud, and an exit seal, which may be a stepped labyrinth type. Von Pragenau (MSFC) has modeled labyrinth seals as a series of plain annular seals for leakage and dynamic coefficient prediction. These multi-tooth components increase the total number of 'flow coupled' components in the ILP. Childs developed an analysis for an ILP consisting of a single, constant clearance shroud with an exit seal represented by a lumped flow-loss coefficient. This same geometry was later extended to include compressible flow. The objective of the current work is to: supply ILP leakage-force impedance-dynamic coefficient modeling software to MSFC engineers, base on incompressible/compressible bulk flow theory; design the software to model a generic geometry ILP described by a series of components lying along an arbitrarily directed path; validate the software by comparison to available test data, CFD and bulk models; and develop a hybrid CFD-bulk flow model of an ILP to improve modeling accuracy within practical run time constraints.

High repetition rate sealed CO2 TEA lasers using heterogeneous catalysts

NASA Astrophysics Data System (ADS)

Price, H. T.; Shaw, S. R.

1987-04-01

The significant operational advantages offered by CO2 lasers, operating in the 10.6 micron region of the spectrum, over current solid state lasers, emitting in the near IR region, have prompted increased interest in the development of compact, reliable, rugged CO2 laser sources. Perhaps the most critical aspect associated with achieving a laser compatible with military use is the development of lasers which require no gas replenishment. Sealed, single shot, CO2 TEA lasers have been available for a number of years. Stark et al were first to demonstrate reliable sealed operation in single shot CO2 TEA lasers in 1975 using gas catalysis. GEC Avionics reported the compact, environmentally qualified, MKIII CO2 TEA laser with a pulse life of greater than 10 to the 6th power pulses in 1980. A sealed laser lifetime of greater than 10 to the 6th power pulses is acceptable for single shot cases, such as direct detection rangefinders for tank laser sights. However, in many other applications, such as tracking of fast moving targets, it is essential that a repetition rate of typically 30Hz to 100Hz is employed. In such cases, a pulse lifetime of 10 to the 6th power pulses is no longer sufficient and a minimum pulse lifetime 10 to the 7th power pulses is essential to ensure a useful service life. In 1983 Stark el al described a sealed, 100Hz CO2 TEA laser, with a life of greater than 2.6 x 10 to the 6th power, which employed heterogeneous catalysis. Following this pioneering work, GEC Avionics has been engaged in the development of sealed high repetition rate lasers with a pulse lifetime of 20 million pulses.

High repetition rate sealed CO2 TEA lasers using heterogeneous catalysts

NASA Technical Reports Server (NTRS)

Price, H. T.; Shaw, S. R.

1987-01-01

The significant operational advantages offered by CO2 lasers, operating in the 10.6 micron region of the spectrum, over current solid state lasers, emitting in the near IR region, have prompted increased interest in the development of compact, reliable, rugged CO2 laser sources. Perhaps the most critical aspect associated with achieving a laser compatible with military use is the development of lasers which require no gas replenishment. Sealed, single shot, CO2 TEA lasers have been available for a number of years. Stark et al were first to demonstrate reliable sealed operation in single shot CO2 TEA lasers in 1975 using gas catalysis. GEC Avionics reported the compact, environmentally qualified, MKIII CO2 TEA laser with a pulse life of greater than 10 to the 6th power pulses in 1980. A sealed laser lifetime of greater than 10 to the 6th power pulses is acceptable for single shot cases, such as direct detection rangefinders for tank laser sights. However, in many other applications, such as tracking of fast moving targets, it is essential that a repetition rate of typically 30Hz to 100Hz is employed. In such cases, a pulse lifetime of 10 to the 6th power pulses is no longer sufficient and a minimum pulse lifetime 10 to the 7th power pulses is essential to ensure a useful service life. In 1983 Stark el al described a sealed, 100Hz CO2 TEA laser, with a life of greater than 2.6 x 10 to the 6th power, which employed heterogeneous catalysis. Following this pioneering work, GEC Avionics has been engaged in the development of sealed high repetition rate lasers with a pulse lifetime of 20 million pulses.

47 CFR 52.20 - Thousands-block number pooling.

Code of Federal Regulations, 2010 CFR

2010-10-01

... separated into ten sequential blocks of 1,000 numbers each (thousands-blocks), and allocated separately... required to participate in thousands-block number pooling shall donate thousands-blocks with ten percent or... ten percent or less contaminated, as an initial block or footprint block. (d) Thousands-Block Pooling...

Understanding and simulating the material behavior during multi-particle irradiations

PubMed Central

Mir, Anamul H.; Toulemonde, M.; Jegou, C.; Miro, S.; Serruys, Y.; Bouffard, S.; Peuget, S.

2016-01-01

A number of studies have suggested that the irradiation behavior and damage processes occurring during sequential and simultaneous particle irradiations can significantly differ. Currently, there is no definite answer as to why and when such differences are seen. Additionally, the conventional multi-particle irradiation facilities cannot correctly reproduce the complex irradiation scenarios experienced in a number of environments like space and nuclear reactors. Therefore, a better understanding of multi-particle irradiation problems and possible alternatives are needed. This study shows ionization induced thermal spike and defect recovery during sequential and simultaneous ion irradiation of amorphous silica. The simultaneous irradiation scenario is shown to be equivalent to multiple small sequential irradiation scenarios containing latent damage formation and recovery mechanisms. The results highlight the absence of any new damage mechanism and time-space correlation between various damage events during simultaneous irradiation of amorphous silica. This offers a new and convenient way to simulate and understand complex multi-particle irradiation problems. PMID:27466040

On sorption and swelling of CO 2 in clays

DOE PAGES

Busch, A.; Bertier, P.; Gensterblum, Y.; ...

2016-03-23

One well-studied technology is the geological storage of carbon dioxide (CO 2), and a number of demonstration projects around the world have proven its feasibility and challenges. Storage conformance and seal integrity are among the most important aspects, as they determine risk of leakage as well as limits for storage capacity and injectivity. By providing evidence for safe storage is critical for improving public acceptance. Most caprocks are composed of clays as dominant mineral type which can typically be illite, kaolinite, chlorite or smectite. A number of recent studies addressed the interaction between CO 2 and these different clays andmore » it was shown that clay minerals adsorb considerable quantities of CO 2. For smectite this uptake can lead to volumetric expansion followed by the generation of swelling pressures. On the one hand CO 2 adsorption traps CO 2, on the other hand swelling pressures can potentially change local stress regimes and in unfavourable situations shear-type failure is assumed to occur. Moreover, for storage in a reservoir having high clay contents the CO 2 uptake can add to storage capacity which is widely underestimated so far. Smectite-rich seals in direct contact with a dry CO 2 plume at the interface to the reservoir might dehydrate leading to dehydration cracks. Such dehydration cracks can provide pathways for CO 2 ingress and further accelerate dewatering and penetration of the seal by supercritical CO 2. At the same time, swelling may also lead to the closure of fractures or the reduction of fracture apertures, thereby improving seal integrity. Finally, the goal of this communication is to theoretically evaluate and discuss these scenarios in greater detail in terms of phenomenological mechanisms, but also in terms of potential risks or benefits for carbon storage.« less

Studies of soft x-ray transmission through grid supported CH layers

NASA Astrophysics Data System (ADS)

Davis, J. S.; Keiter, P. A.; Klein, S. R.; Frank, Y.; Drake, R. P.; Shvarts, D.

2017-10-01

Recent experiments have shown that it may be possible to use laser-heated high-Z foils to drive new radiation transport (RadTran) experiments in gas fill tubes. These tubes must be pressurized above 1atm and the x-ray source needs to be physically separated from the gas. To achieve this, a grid-supported CH seal is implemented. The grid reduces the total surface area of the gas-seal interaction region lowering the thickness requirements for the CH layer. However, as mesh spacing is reduced, hole closure from wire ablation may reduce the x-ray flux. To optimize the seal design, experiments were performed measuring x-ray transmission through CH layers supported by meshes composed of copper, gold, or stainless steel and using hexagonal or square mesh geometries. The x-ray source was formed by heating a 0.5 μm thick planar gold foil with a 4 ns laser pulse at an intensity of 2 ×1014 W / cm 2. Emission data was collected using an x-ray framing camera and a Dante photodiode array. Experiments show that the CH layers can reach effective temperatures of nearly 100 eV but mesh design significantly affects performance, with a nearly 20 eV difference between the best and worst performing seal targets. This talk will discuss our findings and their impact on future RadTran experiments. This work is funded by the U.S. DOE, through the NNSA-DS and SC-OFES Joint Program in HED Laboratory Plasmas, Grant Number DE-NA0001840, the National LUFP, Grant Number DE-NA0000850, and through NNSA/OICF under Cooperatvie Agreement No. DE-FC52-08NA2830.

Topics in the Sequential Design of Experiments

DTIC Science & Technology

1992-03-01

decision , unless so designated by other documentation. 12a. DISTRIBUTION /AVAILABIIUTY STATEMENT 12b. DISTRIBUTION CODE Approved for public release...3 0 1992 D 14. SUBJECT TERMS 15. NUMBER OF PAGES12 Design of Experiments, Renewal Theory , Sequential Testing 1 2. PRICE CODE Limit Theory , Local...distributions for one parameter exponential families," by Michael Woodroofe. Stntca, 2 (1991), 91-112. [6] "A non linear renewal theory for a functional of

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

DOEpatents

Wright, Steven A.; Fuller, Robert L.

2014-08-05

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

Design guide for helicopter transmission seals

NASA Technical Reports Server (NTRS)

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

1974-01-01

A detailed approach for the selection and design of seals for helicopter transmissions is presented. There are two major types of seals presently being used and they are lip type seals and mechanical type seals. Lip type seals can be divided in conventional lip seals and hydrodynamic lip seals. Conventional lip seals can be used for slow-speed, low-pressure, low-temperature sealing. Hydrodynamic lip seals although they are as pressure and temperature limited as conventional lip seals, can operate at a higher speed. Mechanical types seals are comprised of face seals and circumferential seals. Face seals are capable of high speed, high pressure, and high temperature. Circumferential seals can be used in high-speed and high-temperature applications, but will leak excessively at moderate pressures. The performance goals of transmission seals are a life that is at least equal to the scheduled overhaul interval of the gearbox component and a leakage rate of near zero.

Organometallic exposure dependence on organic–inorganic hybrid material formation in polyethylene terephthalate and polyamide 6 polymer fibers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Akyildiz, Halil I.; Jur, Jesse S., E-mail: jsjur@ncsu.edu

2015-03-15

The effect of exposure conditions and surface area on hybrid material formation during sequential vapor infiltrations of trimethylaluminum (TMA) into polyamide 6 (PA6) and polyethylene terephthalate (PET) fibers is investigated. Mass gain of the fabric samples after infiltration was examined to elucidate the reaction extent with increasing number of sequential TMA single exposures, defined as the times for a TMA dose and a hold period. An interdependent relationship between dosing time and holding time on the hybrid material formation is observed for TMA exposure PET, exhibited as a linear trend between the mass gain and total exposure (dose time ×more » hold time × number of sequential exposures). Deviation from this linear relationship is only observed under very long dose or hold times. In comparison, amount of hybrid material formed during sequential exposures to PA6 fibers is found to be highly dependent on amount of TMA dosed. Increasing the surface area of the fiber by altering its cross-sectional dimension is shown to have little on the reaction behavior but does allow for improved diffusion of the TMA into the fiber. This work allows for the projection of exposure parameters necessary for future high-throughput hybrid modifications to polymer materials.« less

Continued results of the seeds in space experiment

NASA Technical Reports Server (NTRS)

Alston, Jim A.

1992-01-01

Two million seeds of 120 different varieties representing 106 species, 97 genera, and 55 plant families were flown aboard the Long Duration Exposure Facility (LDEF). The seeds were housed on the Space Exposed Experiment Developed for Students (SEEDS) tray in the sealed canister number 6 and in two small vented canisters. The seeds were germinated and the germination rates and development of the resulting plants compared to the control seed that stayed in the storage facility. There was a better survival rate in the sealed canister in space than in the storage facility. At least some of the seed in the vented canisters survived the exposure to vacuum for almost six years. The number of observed mutations was very low. In the initial testing, the small seeded crops were not grown to maturity to check for mutation and obtain a second generation seed. These small seeded crops are now being grown for evaluation.

Turbine with radial acting seal

DOEpatents

Eng, Darryl S; Ebert, Todd A

2016-11-22

A floating brush seal in a rim cavity of a turbine in a gas turbine engine, where the floating brush seal includes a seal holder in which the floating brush seal floats, and a expandable seal that fits within two radial extending seal slots that maintains a seal with radial displacement of the floating brush seal and the seal holder.

Surface conforming thermal/pressure seal. [tail assemblies of space shuttle orbiters

NASA Technical Reports Server (NTRS)

Stevens, M. L. (Inventor)

1981-01-01

An assembly is disclosed for sealing a variable gap between the surface of element and a second element in movable relation to it. A seal housing is attached to the second element for movement therewith and has a sealing surface. At least one elongated seal member carried by the housing has first and second conjugate sealing surfaces. The first sealing surface is for rubbing and sealing engagement with the first element surface and the second sealing surface is for sliding and sealing engagement with the housing sealing surface. A biasing assembly may be carried by the housing for biasing the first and second conjugate sealing surfaces of the sealing member toward sealing engagement with the first element surface and housing sealing surface, respectively.

Deficits in sequential processing manifest in motor and linguistic tasks in a multigenerational family with childhood apraxia of speech

PubMed Central

PETER, BEATE; BUTTON, LE; STOEL-GAMMON, CAROL; CHAPMAN, KATHY; RASKIND, WENDY H.

2013-01-01

The purpose of this study was to evaluate a global deficit in sequential processing as candidate endophenotypein a family with familial childhood apraxia of speech (CAS). Of 10 adults and 13 children in a three-generational family with speech sound disorder (SSD) consistent with CAS, 3 adults and 6 children had past or present SSD diagnoses. Two preschoolers with unremediated CAS showed a high number of sequencing errors during single-word production. Performance on tasks with high sequential processing loads differentiated between the affected and unaffected family members, whereas there were no group differences in tasks with low processing loads. Adults with a history of SSD produced more sequencing errors during nonword and multisyllabic real word imitation, compared to those without such a history. Results are consistent with a global deficit in sequential processing that influences speech development as well as cognitive and linguistic processing. PMID:23339324

A stacked sequential learning method for investigator name recognition from web-based medical articles

NASA Astrophysics Data System (ADS)

Zhang, Xiaoli; Zou, Jie; Le, Daniel X.; Thoma, George

2010-01-01

"Investigator Names" is a newly required field in MEDLINE citations. It consists of personal names listed as members of corporate organizations in an article. Extracting investigator names automatically is necessary because of the increasing volume of articles reporting collaborative biomedical research in which a large number of investigators participate. In this paper, we present an SVM-based stacked sequential learning method in a novel application - recognizing named entities such as the first and last names of investigators from online medical journal articles. Stacked sequential learning is a meta-learning algorithm which can boost any base learner. It exploits contextual information by adding the predicted labels of the surrounding tokens as features. We apply this method to tag words in text paragraphs containing investigator names, and demonstrate that stacked sequential learning improves the performance of a nonsequential base learner such as an SVM classifier.

Fuel cell manifold sealing system

DOEpatents

Grevstad, Paul E.; Johnson, Carl K.; Mientek, Anthony P.

1980-01-01

A manifold-to-stack seal and sealing method for fuel cell stacks. This seal system solves the problem of maintaining a low leak rate manifold seal as the fuel cell stack undergoes compressive creep. The seal system eliminates the problem of the manifold-to-stack seal sliding against the rough stack surface as the stack becomes shorter because of cell creep, which relative motion destroys the seal. The seal system described herein utilizes a polymer seal frame firmly clamped between the manifold and the stack such that the seal frame moves with the stack. Thus, as the stack creeps, the seal frame creeps with it, and there is no sliding at the rough, tough to seal, stack-to-seal frame interface. Here the sliding is on a smooth easy to seal location between the seal frame and the manifold.

Method for producing a fuel cell manifold seal

DOEpatents

Grevstad, Paul E.; Johnson, Carl K.; Mientek, Anthony P.

1982-01-01

A manifold-to-stack seal and sealing method for fuel cell stacks. This seal system solves the problem of maintaining a low leak rate manifold seal as the fuel cell stack undergoes compressive creep. The seal system eliminates the problem of the manifold-to-stack seal sliding against the rough stack surface as the stack becomes shorter because of cell creep, which relative motion destroys the seal. The seal system described herein utilizes a polymer seal frame firmly clamped between the manifold and the stack such that the seal frame moves with the stack. Thus, as the stack creeps, the seal frame creeps with it, and there is no sliding at the rough, tough to seal, stack-to-seal frame interface. Here the sliding is on a smooth easy to seal location between the seal frame and the manifold.

Multi-speed multi-phase resolver converter

NASA Technical Reports Server (NTRS)

Alhorn, Dean (Inventor); Howard, David (Inventor)

1994-01-01

A multiphase converter circuit generates a plurality of sinusoidal outputs of displaced phase and given speed value from the output of an angular resolver system attachable to a motor excited by these multi-phase outputs, the resolver system having a lower speed value than that of the motor. The angular resolver system provides in parallel format sequential digital numbers indicative of the amount of rotation of the shaft of an angular position sensor associated with the angular resolver system. These numbers are used to excite simultaneously identical addresses of a plurality of addressable memory systems, each memory system having stored therein at sequential addresses sequential values of a sinusoidal wavetrain of a given number of sinusoids. The stored wavetrain values represent sinusoids displaced from each other in phase according to the number of output phases desired. A digital-to-analog converter associated with each memory system converts each accessed word to a corresponding analog value to generate attendant to rotation of the angular resolver a sinusoidal wave of proper phase at each of the plurality of outputs. By properly orienting the angular resolver system with respect to the rotor of the motor, essentially ripple-free torque is supplied to the rotor. The angular resolver system may employ an analog resolver feeding an integrated circuit resolver-to-digital converter to produce the requisite digital values serving as addresses. Alternative versions employing incremental or absolute encoders are also described.

Multi-speed multi-phase resolver converter

NASA Technical Reports Server (NTRS)

Alhorn, Dean C. (Inventor); Howard, David E. (Inventor)

1995-01-01

A multiphase converter circuit generates a plurality of sinusoidal outputs of displaced phase and given speed value from the output of an angular resolver system attachable to a motor excited by these multi-phase outputs, the resolver system having a lower speed value than that of the motor. The angular resolver system provides in parallel format sequential digital numbers indicative of the amount of rotation of the shaft of an angular position sensor associated with the angular resolver system. These numbers are used to excite simultaneously identical addresses of a plurality of addressable memory systems, each memory system having stored therein at sequential addresses sequential values of a sinusoidal wavetrain of a given number of sinusoids. The stored wavetrain values represent sinusoids displaced from each other in phase according to the number of output phases desired. A digital-to-analog converter associated with each memory system converts each accessed word to a corresponding analog value to generate attendant to rotation of the angular resolver a sinusoidal wave of proper phase at each of the plurality of outputs. By properly orienting the angular resolver system with respect to the rotor of the motor, essentially ripple-free torque is supplied to the rotor. The angular resolver system may employ an analog resolver feeding an integrated circuit resolver-to-digital converter to produce the requisite digital values serving as addresses. Alternative versions employing incremental or absolute encoders are also described.

Efficient sequential and parallel algorithms for record linkage

PubMed Central

Mamun, Abdullah-Al; Mi, Tian; Aseltine, Robert; Rajasekaran, Sanguthevar

2014-01-01

Background and objective Integrating data from multiple sources is a crucial and challenging problem. Even though there exist numerous algorithms for record linkage or deduplication, they suffer from either large time needs or restrictions on the number of datasets that they can integrate. In this paper we report efficient sequential and parallel algorithms for record linkage which handle any number of datasets and outperform previous algorithms. Methods Our algorithms employ hierarchical clustering algorithms as the basis. A key idea that we use is radix sorting on certain attributes to eliminate identical records before any further processing. Another novel idea is to form a graph that links similar records and find the connected components. Results Our sequential and parallel algorithms have been tested on a real dataset of 1 083 878 records and synthetic datasets ranging in size from 50 000 to 9 000 000 records. Our sequential algorithm runs at least two times faster, for any dataset, than the previous best-known algorithm, the two-phase algorithm using faster computation of the edit distance (TPA (FCED)). The speedups obtained by our parallel algorithm are almost linear. For example, we get a speedup of 7.5 with 8 cores (residing in a single node), 14.1 with 16 cores (residing in two nodes), and 26.4 with 32 cores (residing in four nodes). Conclusions We have compared the performance of our sequential algorithm with TPA (FCED) and found that our algorithm outperforms the previous one. The accuracy is the same as that of this previous best-known algorithm. PMID:24154837

A new approach to the solution of the linear mixing model for a single isotope: application to the case of an opportunistic predator.

PubMed

Hall-Aspland, S A; Hall, A P; Rogers, T L

2005-03-01

Mixing models are used to determine diets where the number of prey items are greater than one, however, the limitation of the linear mixing method is the lack of a unique solution when the number of potential sources is greater than the number (n) of isotopic signatures +1. Using the IsoSource program all possible combinations of each source contribution (0-100%) in preselected small increments can be examined and a range of values produced for each sample analysed. We propose the use of a Moore Penrose (M-P) pseudoinverse, which involves the inverse of a 2x2 matrix. This is easily generalized to the case of a single isotope with (p) prey sources and produces a specific solution. The Antarctic leopard seal (Hydrurga leptonyx) was used as a model species to test this method. This seal is an opportunistic predator, which preys on a wide range of species including seals, penguins, fish and krill. The M-P method was used to determine the contribution to diet from each of the four prey types based on blood and fur samples collected over three consecutive austral summers. The advantage of the M-P method was the production of a vector of fractions f for each predator isotopic value, allowing us to identify the relative variation in dietary proportions. Comparison of the calculated fractions from this method with 'means' from IsoSource allowed confidence in the new approach for the case of a single isotope, N.

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

PubMed

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.

Sequential memory: Binding dynamics

NASA Astrophysics Data System (ADS)

Afraimovich, Valentin; Gong, Xue; Rabinovich, Mikhail

2015-10-01

Temporal order memories are critical for everyday animal and human functioning. Experiments and our own experience show that the binding or association of various features of an event together and the maintaining of multimodality events in sequential order are the key components of any sequential memories—episodic, semantic, working, etc. We study a robustness of binding sequential dynamics based on our previously introduced model in the form of generalized Lotka-Volterra equations. In the phase space of the model, there exists a multi-dimensional binding heteroclinic network consisting of saddle equilibrium points and heteroclinic trajectories joining them. We prove here the robustness of the binding sequential dynamics, i.e., the feasibility phenomenon for coupled heteroclinic networks: for each collection of successive heteroclinic trajectories inside the unified networks, there is an open set of initial points such that the trajectory going through each of them follows the prescribed collection staying in a small neighborhood of it. We show also that the symbolic complexity function of the system restricted to this neighborhood is a polynomial of degree L - 1, where L is the number of modalities.

Early Astronomical Sequential Photography, 1873-1923

NASA Astrophysics Data System (ADS)

Bonifácio, Vitor

2011-11-01

In 1873 Jules Janssen conceived the first automatic sequential photographic apparatus to observe the eagerly anticipated 1874 transit of Venus. This device, the 'photographic revolver', is commonly considered today as the earliest cinema precursor. In the following years, in order to study the variability or the motion of celestial objects, several instruments, either manually or automatically actuated, were devised to obtain as many photographs as possible of astronomical events in a short time interval. In this paper we strive to identify from the available documents the attempts made between 1873 and 1923, and discuss the motivations behind them and the results obtained. During the time period studied astronomical sequential photography was employed to determine the time of the instants of contact in transits and occultations, and to study total solar eclipses. The technique was seldom used but apparently the modern film camera invention played no role on this situation. Astronomical sequential photographs were obtained both before and after 1895. We conclude that the development of astronomical sequential photography was constrained by the reduced number of subjects to which the technique could be applied.

Sequential memory: Binding dynamics.

PubMed

Afraimovich, Valentin; Gong, Xue; Rabinovich, Mikhail

2015-10-01

Temporal order memories are critical for everyday animal and human functioning. Experiments and our own experience show that the binding or association of various features of an event together and the maintaining of multimodality events in sequential order are the key components of any sequential memories-episodic, semantic, working, etc. We study a robustness of binding sequential dynamics based on our previously introduced model in the form of generalized Lotka-Volterra equations. In the phase space of the model, there exists a multi-dimensional binding heteroclinic network consisting of saddle equilibrium points and heteroclinic trajectories joining them. We prove here the robustness of the binding sequential dynamics, i.e., the feasibility phenomenon for coupled heteroclinic networks: for each collection of successive heteroclinic trajectories inside the unified networks, there is an open set of initial points such that the trajectory going through each of them follows the prescribed collection staying in a small neighborhood of it. We show also that the symbolic complexity function of the system restricted to this neighborhood is a polynomial of degree L - 1, where L is the number of modalities.

Safeguarding a Lunar Rover with Wald's Sequential Probability Ratio Test

NASA Technical Reports Server (NTRS)

Furlong, Michael; Dille, Michael; Wong, Uland; Nefian, Ara

2016-01-01

The virtual bumper is a safeguarding mechanism for autonomous and remotely operated robots. In this paper we take a new approach to the virtual bumper system by using an old statistical test. By using a modified version of Wald's sequential probability ratio test we demonstrate that we can reduce the number of false positive reported by the virtual bumper, thereby saving valuable mission time. We use the concept of sequential probability ratio to control vehicle speed in the presence of possible obstacles in order to increase certainty about whether or not obstacles are present. Our new algorithm reduces the chances of collision by approximately 98 relative to traditional virtual bumper safeguarding without speed control.

Dynamics of Sequential Decision Making

NASA Astrophysics Data System (ADS)

Rabinovich, Mikhail I.; Huerta, Ramón; Afraimovich, Valentin

2006-11-01

We suggest a new paradigm for intelligent decision-making suitable for dynamical sequential activity of animals or artificial autonomous devices that depends on the characteristics of the internal and external world. To do it we introduce a new class of dynamical models that are described by ordinary differential equations with a finite number of possibilities at the decision points, and also include rules solving this uncertainty. Our approach is based on the competition between possible cognitive states using their stable transient dynamics. The model controls the order of choosing successive steps of a sequential activity according to the environment and decision-making criteria. Two strategies (high-risk and risk-aversion conditions) that move the system out of an erratic environment are analyzed.

Photomicrographic images of some features of Uncinaria spp (Nematoda: Ancylostomatidae) from otariid pinnipeds.

PubMed

Lyons, E T; DeLong, R L

2005-03-01

Photomicrographs of several morphologic features of hookworms (Uncinaria spp) from northern fur seal (Callorhinus ursinus) and California sea lion (Zalophus californianus) pups are presented. The main purpose is to show and describe some physical characteristics of hookworms from the two hosts; it is not to decide from these attributes whether the Uncinaria spp are the same species. The number of species of Uncinaria in pinnipeds is uncertain and specimens need to be examined from the various infected seals and sea lions before the taxonomy of these parasites can be clarified. Information in the present paper should aid in this determination.

19 CFR 19.6 - Deposits, withdrawals, blanket permits to withdraw and sealing requirements.

Code of Federal Regulations, 2010 CFR

2010-04-01

... for aircraft or vessel supplies, if consigned to the same daily aircraft flight number or vessel...” in capital letters conspicuously printed or stamped in the top margin. On the form, the proprietor...

Computational Cognitive Neuroscience Modeling of Sequential Skill Learning

DTIC Science & Technology

2016-09-21

101 EAST 27TH STREET STE 4308 AUSTIN , TX 78712 09/21/2016 Final Report DISTRIBUTION A: Distribution approved for public release. Air Force Research ...5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) The University of Texas at Austin 108 E Dean Keeton Stop A8000 Austin , TX ...AFRL-AFOSR-VA-TR-2016-0320 Computational Cognitive Neuroscience Modeling of Sequential Skill Learning David Schnyer UNIVERSITY OF TEXAS AT AUSTIN

Cable tester

NASA Astrophysics Data System (ADS)

Rammage, Robert L.

1990-10-01

A device for sequentially testing the plurality of connectors in a wiring harness is disclosed. The harness is attached to the tester by means of adapter cables and a rotary switch is used to sequentially, individually test the connectors by passing a current through the connector. If the connector is unbroken, a light will flash to show it is electrically sound. The adapters allow a large number of cable configurations to be tested using a single tester configuration.

Continued Investigation of Leakage and Power Loss Test Results for Competing Turbine Engine Seals

NASA Technical Reports Server (NTRS)

Delgado, Irebert R.; Proctor, Margaret P.

2007-01-01

Seal leakage decreases with increasing surface speed due to reduced clearances from disk centrifugal growth. Annular and labyrinth seal leakage are 2-3 times greater than brush and finger seal leakage. Seal leakage rates increase with increasing temperature because of seal clearance growth due to different coefficients of thermal expansion between the seal and test disk. Seal power loss is not strongly affected by inlet temperature. Seal power loss increases with increasing surface speed, seal pressure differential, mass flow rate or flow factor, and radial clearance. The brush and finger seals had nearly the same power loss. Annular and labyrinth seal power loss were higher than finger or brush seal power loss. The brush seal power loss was the lowest and 15-30% lower than annular and labyrinth seal power loss.

Turbine interstage seal with self-balancing capability

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

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 magnetsmore » produce first and second magnetic forces that balance the seal in the engine.« less

Effects of Compression, Staging, and Braid Angle on Braided Rope Seal Performance

NASA Technical Reports Server (NTRS)

Steinetz, Bruce M.; Adams, Michael L.

1997-01-01

Future turbine engines and industrial systems will be operating at increased temperatures to achieve more demanding efficiency and performance goals. In the highest temperature sections of the engine new material systems such as ceramics and intermetallics are being considered to withstand the harsh thermal environment. Components constructed of these low expansion-rate materials experience thermal strains and a resulting reduction of life when rigidly attached to high expansion-rate, superalloy support structures. Seals are being designed to both seal and to serve as compliant mounts allowing for relative thermal growths between high temperature but brittle primary structures and the surrounding support structures. Previous seal research yielded several braided rope seal designs which demonstrated the ability to both seal and serve as a compliant mount. The hybrid seal was constructed of an all-ceramic (alumina-silica) core overbraided with a superalloy wire sheath (cobalt based superalloy). The all ceramic seal was constructed of an all-ceramic (alumina-silica) core overbraided with multiple ceramic (alumina-silica) sheath layers. Program goals for braided rope seals are to improve flow resistance and/or seal resilience. To that end, the current report studies the test results of: baseline and modified hybrid seals; two stage hybrid and two stage all-ceramic seal configurations; and single stage hybrid and single stage all-ceramic seal configurations for a range of seal crush conditions. Hybrid seal modifications include increasing the sheath braid angle and core coverage. For the same percent seal cross-sectional crush, results show that increasing the hybrid seal braid angle increased seal stiffness and seal unit load, resulting in flows approximately one third of the baseline hybrid seal flows. For both hybrid and all-ceramic seals, two stage seal configurations significantly outperformed single stage configurations. Two stage seal flows were at least 30% less than the single stage seal flows for the same seal crush. Furthermore, test results of single stage seals indicate that for both all-ceramic and hybrid seals, a specific seal crush condition exists at which minimum flows are achieved (i.e. increasing seal crush beyond a certain point does not result in better flow performance). Flow results are presented for a range of pressures and temperatures from ambient to 1300 F, before and after scrubbing. Compression tests results show that for both all-ceramic and hybrid seals, seal preload and stiffness increase with seal crush, but residual seal interference remains constant.

Sequential desorption energy of hydrogen from nickel clusters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deepika,; Kumar, Rakesh, E-mail: rakesh@iitrpr.ac.in; R, Kamal Raj.

2015-06-24

We report reversible Hydrogen adsorption on Nickel clusters, which act as a catalyst for solid state storage of Hydrogen on a substrate. First-principles technique is employed to investigate the maximum number of chemically adsorbed Hydrogen molecules on Nickel cluster. We observe a maximum of four Hydrogen molecules adsorbed per Nickel atom, but the average Hydrogen molecules adsorbed per Nickel atom decrease with cluster size. The dissociative chemisorption energy per Hydrogen molecule and sequential desorption energy per Hydrogen atom on Nickel cluster is found to decrease with number of adsorbed Hydrogen molecules, which on optimization may help in economical storage andmore » regeneration of Hydrogen as a clean energy carrier.« less

Overview of LIDS Docking and Berthing System Seals

NASA Technical Reports Server (NTRS)

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

2007-01-01

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

Overview of NASA Glenn Seal Program

NASA Technical Reports Server (NTRS)

Steinetz, Bruce M.; Proctor, Margaret P.; Dunlap, Patrick H., Jr.; Delgado, Irebert; DeMange, Jeffrey J.; Daniels, Christopher C.; Lattime, Scott B.

2003-01-01

The Seal Team is divided into four primary areas. These areas include turbine engine seal development, structural seal development, acoustic seal development, and adaptive seal development. The turbine seal area focuses on high temperature, high speed shaft seals for secondary air system flow management. The structural seal area focuses on high temperature, resilient structural seals required to accommodate large structural distortions for both space- and aero-applications. Our goal in the acoustic seal project is to develop non-contacting, low leakage seals exploiting the principles of advanced acoustics. We are currently investigating a new acoustic field known as Resonant Macrosonic Synthesis (RMS) to see if we can harness the large acoustic standing pressure waves to form an effective air-barrier/seal. Our goal in the adaptive seal project is to develop advanced sealing approaches for minimizing blade-tip (shroud) or interstage seal leakage. We are planning on applying either rub-avoidance or regeneration clearance control concepts (including smart structures and materials) to promote higher turbine engine efficiency and longer service lives.

Rotary shaft sealing assembly

DOEpatents

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

2013-08-13

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

Rotary shaft sealing assembly

DOEpatents

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

2010-09-21

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

Increasing efficiency of preclinical research by group sequential designs

PubMed Central

Piper, Sophie K.; Rex, Andre; Florez-Vargas, Oscar; Karystianis, George; Schneider, Alice; Wellwood, Ian; Siegerink, Bob; Ioannidis, John P. A.; Kimmelman, Jonathan; Dirnagl, Ulrich

2017-01-01

Despite the potential benefits of sequential designs, studies evaluating treatments or experimental manipulations in preclinical experimental biomedicine almost exclusively use classical block designs. Our aim with this article is to bring the existing methodology of group sequential designs to the attention of researchers in the preclinical field and to clearly illustrate its potential utility. Group sequential designs can offer higher efficiency than traditional methods and are increasingly used in clinical trials. Using simulation of data, we demonstrate that group sequential designs have the potential to improve the efficiency of experimental studies, even when sample sizes are very small, as is currently prevalent in preclinical experimental biomedicine. When simulating data with a large effect size of d = 1 and a sample size of n = 18 per group, sequential frequentist analysis consumes in the long run only around 80% of the planned number of experimental units. In larger trials (n = 36 per group), additional stopping rules for futility lead to the saving of resources of up to 30% compared to block designs. We argue that these savings should be invested to increase sample sizes and hence power, since the currently underpowered experiments in preclinical biomedicine are a major threat to the value and predictiveness in this research domain. PMID:28282371

Continued Investigation of Leakage and Power Loss Test Results for Competing Turbine Engine Seals

NASA Technical Reports Server (NTRS)

Delgado, Irebert R.; Proctor, Margaret P.

2006-01-01

Secondary seal leakage in jet engine applications results in power losses to the engine cycle. Likewise, seal power loss in jet engines not only result in efficiency loss but also increase the heat input into the engine resulting in reduced component lives. Experimental work on labyrinth and annular seals was performed at NASA Glenn Research Center to quantify seal leakage and power loss at various temperatures, seal pressure differentials, and surface speeds. Data from annular and labyrinth seals are compared with previous brush and finger seal test results. Data are also compared to literature. Annular and labyrinth seal leakage rates are 2 to 3 times greater than brush and finger seal rates. Seal leakage decreases with increasing speed but increases with increasing test temperature due to thermal expansion mismatch. Also seal power loss increases with surface speed, seal pressure differential, mass flow rate, and radial clearance. Annular and labyrinth seal power losses were higher than those of brush or finger seal data. The brush seal power loss was 15 to 30 percent lower than annular and labyrinth seal power loss.

How do seal whiskers suppress vortex shedding

NASA Astrophysics Data System (ADS)

Rinehart, Aidan; Flaherty, Justin; Bunjavick, Joseph; Shyam, Vikram; Zhang, Wei

2016-11-01

Certain seal whiskers possess a unique geometry that significantly reduces the vortex-induced vibration; which has attracted great attention to understand how the unique shape re-organizes the wake structure and its potential for passive flow control. The shape of the whiskers can be described as an elliptical cross-section that is lofted along the length of the whisker. Along the entire length of the whisker the ellipse varies in major and minor axis as well as angle of incidence with respect to the axis of the whisker. Of particular interest in this study is to identify what effect the angle of incidence has on the flow structure around the whisker, which has been overlooked in the past. The study will analyze the wake structure behind various scaled-up whisker models using particle image velocimitry (PIV). These whisker models share common geometry dimensions except for the angle of incidence. Flow conditions are created in a water channel and a wind tunnel, covering a wide range of Reynolds number (a few hundreds to thousands), similar to the ambient flow environment of seals and to the targeted aero-propulsion applications. This study will help address knowledge gaps in understanding of how certain geometry features of seal whiskers influence the wake and establish best practices for its application as effective passive flow control strategy.

Alaska harbor seal (Phoca vitulina) contaminants: A review with annotated bibliography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Papa, R.S.; Becker, P.R.

1998-10-01

The numbers of harbor seals (Phoca vitulina) have declined steadily and substantially over the last two decades in the Central and Western Gulf of Alaska, including Prince William Sound. Although the reasons for this decline have not been identified, hypotheses have included fishery interactions, changes in availability of food resources, human harvests, disease, increase in predation, increase in disturbance, and pollution. Although the presence of contaminants has been suggested as one possible causative factor in the decline of both the harbor seal and Steller sea lion, very little information is readily available on contaminant concentrations in these animals. As anmore » initial step in the development of a database that can be used to define the types of studies needed to address the possible role of anthropogenic contaminants in the decline of this species, existing data and information on levels of contaminants in the harbor seals of Alaska, the contiguous U.S., and other areas of the world were reviewed. This report provides references and current scientific literature, as well as gray literature and unpublished databases. This report is divided into three sections: (1) a synthesis of information based on the review, (2) tables that summarize the published data, and (3) an annotated bibliography.« less

Water-soluble vitamin homeostasis in fasting northern elephant seals (Mirounga angustirostris) measured by metabolomics analysis and standard methods

PubMed Central

Boaz, Segal M.; Champagne, Cory D.; Fowler, Melinda A.; Houser, Dorian H.; Crocker, Daniel E.

2011-01-01

Despite the importance of water-soluble vitamins to metabolism, there is limited knowledge of their serum availability in fasting wildlife. We evaluated changes in water-soluble vitamins in northern elephant seals, a species with an exceptional ability to withstand nutrient deprivation. We used a metabolomics approach to measure vitamins and associated metabolites under extended natural fasts for up to seven weeks in free-ranging lactating or developing seals. Water-soluble vitamins were not detected with this metabolomics platform, but could be measured with standard assays. Concentrations of measured vitamins varied independently, but all were maintained at detectable levels over extended fasts, suggesting that defense of vitamin levels is a component of fasting adaptation in the seals. Metabolomics was not ideal for generating complete vitamin profiles in this species, but gave novel insights into vitamin metabolism by detecting key related metabolites. For example, niacin level reductions in lactating females were associated with significant reductions in precursors suggesting downregulation of the niacin synthetic pathway. The ability to detect individual vitamins using metabolomics may be impacted by the large number of novel compounds detected. Modifications to the analysis platforms and compound detection algorithms used in this study may be required for improving water-soluble vitamin detection in this and other novel wildlife systems. PMID:21983145

Triple acting radial seal

DOEpatents

Ebert, Todd A [West Palm Beach, FL; Carella, John A [Jupiter, FL

2012-03-13

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

Report number codes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nelson, R.N.

This publication lists all report number codes processed by the Office of Scientific and Technical Information. The report codes are substantially based on the American National Standards Institute, Standard Technical Report Number (STRN)-Format and Creation Z39.23-1983. The Standard Technical Report Number (STRN) provides one of the primary methods of identifying a specific technical report. The STRN consists of two parts: The report code and the sequential number. The report code identifies the issuing organization, a specific program, or a type of document. The sequential number, which is assigned in sequence by each report issuing entity, is not included in thismore » publication. Part I of this compilation is alphabetized by report codes followed by issuing installations. Part II lists the issuing organization followed by the assigned report code(s). In both Parts I and II, the names of issuing organizations appear for the most part in the form used at the time the reports were issued. However, for some of the more prolific installations which have had name changes, all entries have been merged under the current name.« less

Comparison of two commercial embryo culture media (SAGE-1 step single medium vs. G1-PLUSTM/G2-PLUSTM sequential media): Influence on in vitro fertilization outcomes and human embryo quality.

PubMed

López-Pelayo, Iratxe; Gutiérrez-Romero, Javier María; Armada, Ana Isabel Mangano; Calero-Ruiz, María Mercedes; Acevedo-Yagüe, Pablo Javier Moreno de

2018-04-26

To compare embryo quality, fertilization, implantation, miscarriage and clinical pregnancy rates for embryos cultured in two different commercial culture media until D-2 or D-3. In this retrospective study, we analyzed 189 cycles performed in 2016. Metaphase II oocytes were microinjected and allocated into single medium (SAGE 1-STEP, Origio) until transferred, frozen or discarded; or, if sequential media were used, the oocytes were cultured in G1-PLUSTM (Vitrolife) up to D-2 or D-3 and in G2-PLUSTM (Vitrolife) to transfer. On the following day, the oocytes were checked for normal fertilization and on D-2 and D-3 for morphological classification. Statistical analysis was performed using the chi-square and Mann-Whitney tests in PASW Statistics 18.0. The fertilization rates were 70.07% for single and 69.11% for sequential media (p=0.736). The mean number of embryos with high morphological quality (class A/B) was higher in the single medium than in the sequential media: D-2 [class A (190 vs. 107, p<0.001), B (133 vs. 118, p=0.018)]; D-3 [class A (40 vs. 19, p=0.048) but without differences in class B (40 vs. 49)]. Consequently, a higher number of embryos cultured in single medium were frozen: 197 (21.00%) vs. sequential: 102 (11.00%), p<0.001. No differences were found in implantation rates (30.16% vs. 25.57%, p=0.520), clinical pregnancy rates (55.88% vs. 41.05%, p=0.213), or miscarriage rates (14.29% vs. 9.52%, p=0.472). Embryo culture in single medium yields greater efficiency per cycle than in sequential media. Higher embryo quality and quantity were achieved, resulting in more frozen embryos. There were no differences in clinical pregnancy rates.

Nontraditional Fog Seal for Asphalt Pavement : Performance on Shoulder Sections in Minnesota

DOT National Transportation Integrated Search

2018-05-01

The pavement engineering community has recently been introduced to a number of nontraditional products intended for uses as surface sealers for bituminous pavements. Many new products use agricultural-based components and little is known regarding th...

Compliant high temperature seals for dissimilar materials

DOEpatents

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

2001-01-01

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

Seal Related Development Activities at EG/G

NASA Technical Reports Server (NTRS)

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.

Pressure Actuated Leaf Seals for Improved Turbine Shaft Sealing

NASA Technical Reports Server (NTRS)

Grondahl, Clayton

2006-01-01

This presentation introduces a shaft seal in which leaf seal elements are constructed from slotted shim material formed and layered into a frusto-conical assembly. Limited elastic deflection of seal leaves with increasing system pressure close large startup clearance to a small, non-contacting, steady state running clearance. At shutdown seal elements resiliently retract as differential seal pressure diminishes. Large seal clearance during startup and shutdown provides a mechanism for rub avoidance. Minimum operating clearance improves performance and non-contacting operation promises long seal life. Design features of this seal, sample calculations at differential pressures up to 2400 psid and benefit comparison with brush and labyrinth seals is documented in paper, AIAA 2005 3985, presented at the Advanced Seal Technology session of the Joint Propulsion Conference in Tucson this past July. In this presentation use of bimetallic leaf material will be discussed. Frictional heating of bimetallic leaf seals during a seal rub can relieve the rub condition to some extent with a change in seal shape. Improved leaf seal rub tolerance is expected with bimetallic material.

A Comparison of Candidate Seal Designs for Future Docking Systems

NASA Technical Reports Server (NTRS)

Dunlap, Patrick, H., Jr.; Steinetz, Bruce, M.

2012-01-01

NASA is developing a new docking system to support future space exploration missions to low Earth orbit, the Moon, and other destinations. A key component of this system is the seal at the main docking interface which inhibits the loss of cabin air once docking is complete. Depending on the mission, the seal must be able to dock in either a seal-on-flange or seal-on-seal configuration. Seal-on-flange mating would occur when a docking system equipped with a seal docks to a system with a flat metal flange. This would occur when a vehicle docks to a node on the International Space Station. Seal-on-seal mating would occur when two docking systems equipped with seals dock to each other. Two types of seal designs were identified for this application: Gask-O-seals and multi-piece seals. Both types of seals had a pair of seal bulbs to satisfy the redundancy requirement. A series of performance assessments and comparisons were made between the candidate seal designs indicating that they meet the requirements for leak rate and compression and adhesion loads under a range of operating conditions. Other design factors such as part count, integration into the docking system tunnel, seal-on-seal mating, and cost were also considered leading to the selection of the multi-piece seal design for the new docking system. The results of this study can be used by designers of future docking systems and other habitable volumes to select the seal design best-suited for their particular application.

Information Management: Publishing and Printing: Army Publishing: Action Officers Guide

DTIC Science & Technology

2002-04-30

types of lists: ordered (such as numerical, alphabetical, or sequential ), bulleted, or dashed. (4) Extracted material in an appendix must be identified...provide supporting, expanded, or sequential doctrinal manuals within a functional field (this number group must not exceed 3 digits). Table 13–2...rubup, opaquing, lineup , and register, and so forth 1,2 190 DA PAM 25–40 • 30 April 2002 Table J–5 Camera, platemaking, and related equipment—Continued

SEALS: an Innovative Pipeline Program Targeting Obstacles to Diversity in the Physician Workforce.

PubMed

Fritz, Cassandra D L; Press, Valerie G; Nabers, Darrell; Levinson, Dana; Humphrey, Holly; Vela, Monica B

2016-06-01

Medical schools may find implementing pipeline programs for minority pre-medical students prohibitive due to a number of factors including the lack of well-described programs in the literature, the limited evidence for program development, and institutional financial barriers. Our goals were to (1) design a pipeline program based on educational theory; (2) deliver the program in a low cost, sustainable manner; and (3) evaluate intermediate outcomes of the program. SEALS is a 6-week program based on an asset bundles model designed to promote: (1) socialization and professionalism, (2) education in science learning tools, (3) acquisition of finance literacy, (4) the leveraging of mentorship and networks, and (5) social expectations and resilience, among minority pre-medical students. This is a prospective mixed methods study. Students completed survey instruments pre-program, post-program, and 6 months post-program, establishing intermediate outcome measures. Thirteen students matriculated to SEALS. The SEALS cohort rated themselves as improved or significantly improved when asked to rate their familiarity with MCAT components (p < 0.01), ability to ask for a letter of recommendation (p = 0.04), and importance of interview skills (p = 0.04) compared with before the program. Over 90 % of students referenced the health disparities lecture series as an inspiration to advocate for minority health. Six-month surveys suggested that SEALS students acquired and applied four of the five assets at their college campuses. This low-cost, high-quality, program can be undertaken by medical schools interested in promoting a diverse workforce that may ultimately begin to address and reduce health care disparities.

Characteristics of sequential swallowing of liquids in young and elderly adults: an integrative review.

PubMed

Veiga, Helena Perrut; Bianchini, Esther Mandelbaum Gonçalves

2012-01-01

To perform an integrative review of studies on liquid sequential swallowing, by characterizing the methodology of the studies and the most important findings in young and elderly adults. Review of the literature written in English and Portuguese on PubMed, LILACS, SciELO and MEDLINE databases, within the past twenty years, available fully, using the following uniterms: sequential swallowing, swallowing, dysphagia, cup, straw, in various combinations. Research articles with a methodological approach on the characterization of liquid sequential swallowing by young and/or elderly adults, regardless of health condition, excluding studies involving only the esophageal phase. The following research indicators were applied: objectives, number and gender of participants; age group; amount of liquid offered; intake instruction; utensil used, methods and main findings. 18 studies met the established criteria. The articles were categorized according to the sample characterization and the methodology on volume intake, utensil used and types of exams. Most studies investigated only healthy individuals, with no swallowing complaints. Subjects were given different instructions as to the intake of all the volume: usual manner, continually, as rapidly as possible. The findings about the characterization of sequential swallowing were varied and described in accordance with the objectives of each study. It found great variability in the methodology employed to characterize the sequential swallowing. Some findings are not comparable, and sequential swallowing is not studied in most swallowing protocols, without consensus on the influence of the utensil.

Microwave Ablation: Comparison of Simultaneous and Sequential Activation of Multiple Antennas in Liver Model Systems.

PubMed

Harari, Colin M; Magagna, Michelle; Bedoya, Mariajose; Lee, Fred T; Lubner, Meghan G; Hinshaw, J Louis; Ziemlewicz, Timothy; Brace, Christopher L

2016-01-01

To compare microwave ablation zones created by using sequential or simultaneous power delivery in ex vivo and in vivo liver tissue. All procedures were approved by the institutional animal care and use committee. Microwave ablations were performed in both ex vivo and in vivo liver models with a 2.45-GHz system capable of powering up to three antennas simultaneously. Two- and three-antenna arrays were evaluated in each model. Sequential and simultaneous ablations were created by delivering power (50 W ex vivo, 65 W in vivo) for 5 minutes per antenna (10 and 15 minutes total ablation time for sequential ablations, 5 minutes for simultaneous ablations). Thirty-two ablations were performed in ex vivo bovine livers (eight per group) and 28 in the livers of eight swine in vivo (seven per group). Ablation zone size and circularity metrics were determined from ablations excised postmortem. Mixed effects modeling was used to evaluate the influence of power delivery, number of antennas, and tissue type. On average, ablations created by using the simultaneous power delivery technique were larger than those with the sequential technique (P < .05). Simultaneous ablations were also more circular than sequential ablations (P = .0001). Larger and more circular ablations were achieved with three antennas compared with two antennas (P < .05). Ablations were generally smaller in vivo compared with ex vivo. The use of multiple antennas and simultaneous power delivery creates larger, more confluent ablations with greater temperatures than those created with sequential power delivery. © RSNA, 2015.

A randomized prospective controlled trial comparing the laryngeal tube suction disposable and the supreme laryngeal mask airway: the influence of head and neck position on oropharyngeal seal pressure.

PubMed

Somri, Mostafa; Vaida, Sonia; Garcia Fornari, Gustavo; Mendoza, Gabriela Renee; Charco-Mora, Pedro; Hawash, Naser; Matter, Ibrahim; Swaid, Forat; Gaitini, Luis

2016-10-06

The Laryngeal Tube Suction Disposable (LTS-D) and the Supreme Laryngeal Mask Airway (SLMA) are second generation supraglottic airway devices (SADs) with an added channel to allow gastric drainage. We studied the efficacy of these devices when using pressure controlled mechanical ventilation during general anesthesia for short and medium duration surgical procedures and compared the oropharyngeal seal pressure in different head and-neck positions. Eighty patients in each group had either LTS-D or SLMA for airway management. The patients were recruited in two different institutions. Primary outcome variables were the oropharyngeal seal pressures in neutral, flexion, extension, right and left head-neck position. Secondary outcome variables were time to achieve an effective airway, ease of insertion, number of attempts, maneuvers necessary during insertion, ventilatory parameters, success of gastric tube insertion and incidence of complications. The oropharyngeal seal pressure achieved with the LTS-D was higher than the SLMA in, (extension (p=0.0150) and right position (p=0.0268 at 60 cm H 2 O intracuff pressures and nearly significant in neutral position (p = 0.0571). The oropharyngeal seal pressure was significantly higher with the LTS-D during neck extension as compared to SLMA (p= 0.015). Similar oropharyngeal seal pressures were detected in all other positions with each device. The secondary outcomes were comparable between both groups. Patients ventilated with LTS-D had higher incidence of sore throat (p = 0.527). No major complications occurred. Better oropharyngeal seal pressure was achieved with the LTS-D in head-neck right and extension positions , although it did not appear to have significance in alteration of management using pressure control mechanical ventilation in neutral position. The fiberoptic view was better with the SLMA. The post-operative sore throat incidence was higher in the LTS-D. ClinicalTrials.gov ID: NCT02856672 , Unique Protocol ID:BnaiZionMC-16-LG-001, Registered: August 2016.

Twist seal for high-pressure vessels such as space shuttle rocket motors

NASA Technical Reports Server (NTRS)

von Pragenau, George L. (Inventor)

1989-01-01

Seals for sealing clevis and flange joints (14) of a solid rocket booster motor, and more particularly to a seal (30) which is twisted upon application of expansion forces to an edge seal (36). This twisting motion initially causes a leading edge seal (44) to be urged into sealing engagement with a surface (48) of an adjacent member (20) and thereafter, increasing fluid pressure on a pressurized side (64) of a seal (30) drives a broad sealing region (46) into sealing engagement with a surface (48).

Hypersonic engine seal development at NASA Lewis Research Center

NASA Technical Reports Server (NTRS)

Steinetz, Bruce M.

1994-01-01

NASA Lewis Research Center is developing advanced seal concepts and sealing technology for advanced combined cycle ramjet/scramjet engines being designed for the National Aerospace Plane (NASP). Technologies are being developed for both the dynamic seals that seal the sliding interfaces between articulating engine panels and sidewalls, and for the static seals that seal the heat exchanger to back-up structure interfaces. This viewgraph presentation provides an overview of the candidate engine seal concepts, seal material assessments, and unique test facilities used to assess the leakage and thermal performance of the seal concepts.

Brush seals for turbine engine fuel conservation

NASA Astrophysics Data System (ADS)

Sousa, Mike

1994-07-01

The program objective is to demonstrate brush seals for replacing labyrinth seals in turboprop engines. The approach taken was to design and procure brush seals with assistance from Sealol, modify and instrument an existing T407 low pressure turbine test rig, replace inner balance piston and outer balance piston labyrinth seals with brush seals, conduct cyclic tests to evaluate seal leakage at operating pressures and temperatures, and evaluate effect of seal pack width and rotor eccentricity. Results are presented in viewgraph format and show that brush seals offer performance advantages over labyrinth seals.

Development of advanced seals for space propulsion turbomachinery

NASA Technical Reports Server (NTRS)

Hendricks, R. C.; Liang, A. D.; Childs, D. W.; Proctor, M. P.

1992-01-01

Current activities in seals for space propulsion turbomachinery that the NASA Lewis Research Center sponsors are surveyed. The overall objective is to provide the designer and researcher with the concepts and the data to control seal dynamics and leakage. Included in the program are low-leakage seals, such as the brush seal, the 'ceramic rope' seal, low-leakage seals for liquid oxygen turbopumps, face seals for two phase flow, and swirl brakes for stability. Two major efforts are summarized: a seal dynamics in rotating machinery and an effort in seal code development.

Hypersonic engine seal development at NASA Lewis Research Center

NASA Astrophysics Data System (ADS)

Steinetz, Bruce M.

1994-07-01

NASA Lewis Research Center is developing advanced seal concepts and sealing technology for advanced combined cycle ramjet/scramjet engines being designed for the National Aerospace Plane (NASP). Technologies are being developed for both the dynamic seals that seal the sliding interfaces between articulating engine panels and sidewalls, and for the static seals that seal the heat exchanger to back-up structure interfaces. This viewgraph presentation provides an overview of the candidate engine seal concepts, seal material assessments, and unique test facilities used to assess the leakage and thermal performance of the seal concepts.

Improved Murine Blastocyst Quality and Development in a Single Culture Medium Compared to Sequential Culture Media

PubMed Central

Hennings, Justin M.; Zimmer, Randall L.; Nabli, Henda; Davis, J. Wade; Sutovsky, Peter; Sutovsky, Miriam; Sharpe-Timms, Kathy L.

2015-01-01

Objective: Validate single versus sequential culture media for murine embryo development. Design: Prospective laboratory experiment. Setting: Assisted Reproduction Laboratory. Animals: Murine embryos. Interventions: Thawed murine zygotes cultured for 3 or 5 days (d3 or d5) in single or sequential embryo culture media developed for human in vitro fertilization. Main Outcome Measures: On d3, zygotes developing to the 8 cell (8C) stage or greater were quantified using 4’,6-diamidino-2-phenylindole (DAPI), and quality was assessed by morphological analysis. On d5, the number of embryos reaching the blastocyst stage was counted. DAPI was used to quantify total nuclei and inner cell mass nuclei. Localization of ubiquitin C-terminal hydrolase L1 (UCHL1) and ubiquitin C-terminal hydrolase L3 (UCHL3) was reference points for evaluating cell quality. Results: Comparing outcomes in single versus to sequential media, the odds of embryos developing to the 8C stage on d3 were 2.34 time greater (P = .06). On d5, more embryos reached the blastocyst stage (P = <.0001), hatched, and had significantly more trophoblast cells (P = .005) contributing to the increased total cell number. Also at d5, localization of distinct cytoplasmic UCHL1 and nuclear UCHL3 was found in high-quality hatching blastocysts. Localization of UCHL1 and UCHL3 was diffuse and inappropriately dispersed throughout the cytoplasm in low-quality nonhatching blastocysts. Conclusions: Single medium yields greater cell numbers, an increased growth rate, and more hatching of murine embryos. Cytoplasmic UCHL1 and nuclear UHCL3 localization patterns were indicative of embryo quality. Our conclusions are limited to murine embryos but one might speculate that single medium may also be more beneficial for human embryo culture. Human embryo studies are needed. PMID:26668049

Improved Murine Blastocyst Quality and Development in a Single Culture Medium Compared to Sequential Culture Media.

PubMed

Hennings, Justin M; Zimmer, Randall L; Nabli, Henda; Davis, J Wade; Sutovsky, Peter; Sutovsky, Miriam; Sharpe-Timms, Kathy L

2016-03-01

Validate single versus sequential culture media for murine embryo development. Prospective laboratory experiment. Assisted Reproduction Laboratory. Murine embryos. Thawed murine zygotes cultured for 3 or 5 days (d3 or d5) in single or sequential embryo culture media developed for human in vitro fertilization. On d3, zygotes developing to the 8 cell (8C) stage or greater were quantified using 4',6-diamidino-2-phenylindole (DAPI), and quality was assessed by morphological analysis. On d5, the number of embryos reaching the blastocyst stage was counted. DAPI was used to quantify total nuclei and inner cell mass nuclei. Localization of ubiquitin C-terminal hydrolase L1 (UCHL1) and ubiquitin C-terminal hydrolase L3 (UCHL3) was reference points for evaluating cell quality. Comparing outcomes in single versus to sequential media, the odds of embryos developing to the 8C stage on d3 were 2.34 time greater (P = .06). On d5, more embryos reached the blastocyst stage (P = <.0001), hatched, and had significantly more trophoblast cells (P = .005) contributing to the increased total cell number. Also at d5, localization of distinct cytoplasmic UCHL1 and nuclear UCHL3 was found in high-quality hatching blastocysts. Localization of UCHL1 and UCHL3 was diffuse and inappropriately dispersed throughout the cytoplasm in low-quality nonhatching blastocysts. Single medium yields greater cell numbers, an increased growth rate, and more hatching of murine embryos. Cytoplasmic UCHL1 and nuclear UHCL3 localization patterns were indicative of embryo quality. Our conclusions are limited to murine embryos but one might speculate that single medium may also be more beneficial for human embryo culture. Human embryo studies are needed. © The Author(s) 2015.

Impact of primary antibiotic resistance on the effectiveness of sequential therapy for Helicobacter pylori infection: lessons from a 5-year study on a large number of strains.

PubMed

Gatta, L; Scarpignato, C; Fiorini, G; Belsey, J; Saracino, I M; Ricci, C; Vaira, D

2018-05-01

The increasing prevalence of strains resistant to antimicrobial agents is a critical issue in the management of Helicobacter pylori (H. pylori) infection. (1) To evaluate the prevalence of primary resistance to clarithromycin, metronidazole and levofloxacin (2) to assess the effectiveness of sequential therapy on resistant strains (3) to identify the minimum number of subjects to enrol for evaluating the effectiveness of an eradication regimen in patients harbouring resistant strains. Consecutive 1682 treatment naïve H. pylori-positive patients referred for upper GI endoscopy between 2010 and 2015 were studied and resistances assessed by E-test. Sequential therapy was offered, effectiveness evaluated and analysed. H. pylori-primary resistance to antimicrobials tested was high, and increased between 2010 and 2015. Eradication rates were (estimates and 95% CIs): 97.3% (95.6-98.4) in strains susceptible to clarithromycin and metronidazole; 96.1% (91.7-98.2) in strains resistant to metronidazole but susceptible to clarithromycin; 93.4% (88.2-96.4) in strains resistant to clarithromycin but susceptible to metronidazole; 83.1% (77.7-87.3) in strains resistant to clarithromycin and metronidazole. For any treatment with a 75%-85% eradication rate, some 98-144 patients with resistant strains need to be studied to get reliable information on effectiveness in these patients. H. pylori-primary resistance is increasing and represents the most critical factor affecting effectiveness. Sequential therapy eradicated 83% of strains resistant to clarithromycin and metronidazole. Reliable estimates of the effectiveness of a given regimen in patients harbouring resistant strains can be obtained only by assessing a large number of strains. © 2018 John Wiley & Sons Ltd.

Online Sequential Projection Vector Machine with Adaptive Data Mean Update

PubMed Central

Chen, Lin; Jia, Ji-Ting; Zhang, Qiong; Deng, Wan-Yu; Wei, Wei

2016-01-01

We propose a simple online learning algorithm especial for high-dimensional data. The algorithm is referred to as online sequential projection vector machine (OSPVM) which derives from projection vector machine and can learn from data in one-by-one or chunk-by-chunk mode. In OSPVM, data centering, dimension reduction, and neural network training are integrated seamlessly. In particular, the model parameters including (1) the projection vectors for dimension reduction, (2) the input weights, biases, and output weights, and (3) the number of hidden nodes can be updated simultaneously. Moreover, only one parameter, the number of hidden nodes, needs to be determined manually, and this makes it easy for use in real applications. Performance comparison was made on various high-dimensional classification problems for OSPVM against other fast online algorithms including budgeted stochastic gradient descent (BSGD) approach, adaptive multihyperplane machine (AMM), primal estimated subgradient solver (Pegasos), online sequential extreme learning machine (OSELM), and SVD + OSELM (feature selection based on SVD is performed before OSELM). The results obtained demonstrated the superior generalization performance and efficiency of the OSPVM. PMID:27143958

Online Sequential Projection Vector Machine with Adaptive Data Mean Update.

PubMed

Chen, Lin; Jia, Ji-Ting; Zhang, Qiong; Deng, Wan-Yu; Wei, Wei

2016-01-01

We propose a simple online learning algorithm especial for high-dimensional data. The algorithm is referred to as online sequential projection vector machine (OSPVM) which derives from projection vector machine and can learn from data in one-by-one or chunk-by-chunk mode. In OSPVM, data centering, dimension reduction, and neural network training are integrated seamlessly. In particular, the model parameters including (1) the projection vectors for dimension reduction, (2) the input weights, biases, and output weights, and (3) the number of hidden nodes can be updated simultaneously. Moreover, only one parameter, the number of hidden nodes, needs to be determined manually, and this makes it easy for use in real applications. Performance comparison was made on various high-dimensional classification problems for OSPVM against other fast online algorithms including budgeted stochastic gradient descent (BSGD) approach, adaptive multihyperplane machine (AMM), primal estimated subgradient solver (Pegasos), online sequential extreme learning machine (OSELM), and SVD + OSELM (feature selection based on SVD is performed before OSELM). The results obtained demonstrated the superior generalization performance and efficiency of the OSPVM.

76 FR 43266 - Marine Mammals; File No. 16472

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-20

... (Lobodon carcinophagus), leopard seals (Hydrurga leptonyx), Ross seals (Ommatophoca rossii), and Weddell... monitoring program established in 1986. The applicant also requests permission to import tissue samples... seals, 100 crabeater seals, 100 leopard seals, 200 Weddell seals, and 5 Ross seals would be taken...

Improved coverage of cDNA-AFLP by sequential digestion of immobilized cDNA.

PubMed

Weiberg, Arne; Pöhler, Dirk; Morgenstern, Burkhard; Karlovsky, Petr

2008-10-13

cDNA-AFLP is a transcriptomics technique which does not require prior sequence information and can therefore be used as a gene discovery tool. The method is based on selective amplification of cDNA fragments generated by restriction endonucleases, electrophoretic separation of the products and comparison of the band patterns between treated samples and controls. Unequal distribution of restriction sites used to generate cDNA fragments negatively affects the performance of cDNA-AFLP. Some transcripts are represented by more than one fragment while other escape detection, causing redundancy and reducing the coverage of the analysis, respectively. With the goal of improving the coverage of cDNA-AFLP without increasing its redundancy, we designed a modified cDNA-AFLP protocol. Immobilized cDNA is sequentially digested with several restriction endonucleases and the released DNA fragments are collected in mutually exclusive pools. To investigate the performance of the protocol, software tool MECS (Multiple Enzyme cDNA-AFLP Simulation) was written in Perl. cDNA-AFLP protocols described in the literature and the new sequential digestion protocol were simulated on sets of cDNA sequences from mouse, human and Arabidopsis thaliana. The redundancy and coverage, the total number of PCR reactions, and the average fragment length were calculated for each protocol and cDNA set. Simulation revealed that sequential digestion of immobilized cDNA followed by the partitioning of released fragments into mutually exclusive pools outperformed other cDNA-AFLP protocols in terms of coverage, redundancy, fragment length, and the total number of PCRs. Primers generating 30 to 70 amplicons per PCR provided the highest fraction of electrophoretically distinguishable fragments suitable for normalization. For A. thaliana, human and mice transcriptome, the use of two marking enzymes and three sequentially applied releasing enzymes for each of the marking enzymes is recommended.

2003 NASA Seal/Secondary Air System Workshop. Volume 1

NASA Technical Reports Server (NTRS)

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

2004-01-01

The following reports were included in the 2003 NASA Seal/Secondary Air System Workshop:Low Emissions Alternative Power (LEAP); Overview of NASA Glenn Seal Developments; NASA Ultra Efficient Engine Technology Project Overview; Development of Higher Temperature Abradable Seals for Industrial Gas Turbines; High Misalignment Carbon Seals for the Fan Drive Gear System Technologies; Compliant Foil Seal Investigations; Test Rig for Evaluating Active Turbine Blade Tip Clearance Control Concepts; Controls Considerations for Turbine Active Clearance Control; Non-Contacting Finger Seal Developments and Design Considerations; Effect of Flow-Induced Radial Load on Brush Seal/Rotor Contact Mechanics; Seal Developments at Flowserve Corporation; Investigations of High Pressure Acoustic Waves in Resonators With Seal-Like Features; Numerical Investigations of High Pressure Acoustic Waves in Resonators; Feltmetal Seal Material Through-Flow; "Bimodal" Nuclear Thermal Rocket (BNTR) Propulsion for Future Human Mars Exploration Missions; High Temperature Propulsion System Structural Seals for Future Space Launch Vehicles; Advanced Control Surface Seal Development for Future Space Vehicles; High Temperature Metallic Seal Development for Aero Propulsion and Gas Turbine Applications; and BrazeFoil Honeycomb.

High Pressure Rotary Shaft Sealing Mechanism

DOEpatents

Dietle, Lannie; Gobeli, Jeffrey D.

2001-05-08

A laterally translatable pressure staged rotary shaft sealing mechanism having a seal housing with a shaft passage therein being exposed to a fluid pressure P1 and with a rotary shaft being located within the shaft passage. At least one annular laterally translatable seal carrier is provided. First and second annular resilient sealing elements are supported in axially spaced relation by the annular seal carriers and have sealing relation with the rotary shaft. The seal housing and at least one seal carrier define a first pressure staging chamber exposed to the first annular resilient sealing element and a second pressure staging chamber located between and exposed to the first and second annular resilient sealing elements. A first fluid is circulated to the first pressure chamber at a pressure P1, and a second staging pressure fluid is circulated to the second pressure chamber at a fraction of pressure P1 to achieve pressure staging, cooling of the seals. Seal placement provides hydraulic force balancing of the annular seal carriers.

Skew resisting hydrodynamic seal

DOEpatents

Conroy, William T.; Dietle, Lannie L.; Gobeli, Jeffrey D.; Kalsi, Manmohan S.

2001-01-01

A novel hydrodynamically lubricated compression type rotary seal that is suitable for lubricant retention and environmental exclusion. Particularly, the seal geometry ensures constraint of a hydrodynamic seal in a manner preventing skew-induced wear and provides adequate room within the seal gland to accommodate thermal expansion. The seal accommodates large as-manufactured variations in the coefficient of thermal expansion of the sealing material, provides a relatively stiff integral spring effect to minimize pressure-induced shuttling of the seal within the gland, and also maintains interfacial contact pressure within the dynamic sealing interface in an optimum range for efficient hydrodynamic lubrication and environment exclusion. The seal geometry also provides for complete support about the circumference of the seal to receive environmental pressure, as compared the interrupted character of seal support set forth in U.S. Pat. Nos. 5,873,576 and 6,036,192 and provides a hydrodynamic seal which is suitable for use with non-Newtonian lubricants.

Seals Flow Code Development 1993

NASA Technical Reports Server (NTRS)

Liang, Anita D. (Compiler); Hendricks, Robert C. (Compiler)

1994-01-01

Seals Workshop of 1993 code releases include SPIRALI for spiral grooved cylindrical and face seal configurations; IFACE for face seals with pockets, steps, tapers, turbulence, and cavitation; GFACE for gas face seals with 'lift pad' configurations; and SCISEAL, a CFD code for research and design of seals of cylindrical configuration. GUI (graphical user interface) and code usage was discussed with hands on usage of the codes, discussions, comparisons, and industry feedback. Other highlights for the Seals Workshop-93 include environmental and customer driven seal requirements; 'what's coming'; and brush seal developments including flow visualization, numerical analysis, bench testing, T-700 engine testing, tribological pairing and ceramic configurations, and cryogenic and hot gas facility brush seal results. Also discussed are seals for hypersonic engines and dynamic results for spiral groove and smooth annular seals.

Low-leakage and low-instability labyrinth seal

NASA Technical Reports Server (NTRS)

Rhode, David L. (Inventor)

1997-01-01

Improved labyrinth seal designs are disclosed. The present invention relates to labyrinth seal systems with selected sealing surfaces and seal geometry to optimize flow deflection and produce maximum turbulent action. Optimum seal performance is generally accomplished by providing sealing surfaces and fluid cavities formed to dissipate fluid energy as a function of the geometry of the sealing surfaces along with the position and size of the fluid cavities formed between members of the labyrinth seal system. Improved convex surfaces, annular flow reversal grooves, flow deflection blocks and rough, machined surfaces cooperate to enhance the performance of the labyrinth seal systems. For some labyrinth seal systems a mid-cavity throttle and either rigid teeth or flexible spring teeth may be included.

Fundamentals of fluid sealing

NASA Technical Reports Server (NTRS)

Zuk, J.

1976-01-01

The fundamentals of fluid sealing, including seal operating regimes, are discussed and the general fluid-flow equations for fluid sealing are developed. Seal performance parameters such as leakage and power loss are presented. Included in the discussion are the effects of geometry, surface deformations, rotation, and both laminar and turbulent flows. The concept of pressure balancing is presented, as are differences between liquid and gas sealing. Mechanisms of seal surface separation, fundamental friction and wear concepts applicable to seals, seal materials, and pressure-velocity (PV) criteria are discussed.

Sealing device for providing a seal in a turbomachine

DOEpatents

Lacy, Benjamin Paul; Kottilingam, Srikanth Chandrudu; Porter, Christopher Donald; Schick, David Edward; Weber, David Wayne

2016-08-16

Sealing device for providing seals between adjacent components, and turbomachines utilizing such sealing devices, are provided. A sealing device includes a seal plate insertable between the adjacent components, the seal plate comprising a first face and an opposing second face. The sealing device further includes a plurality of pins extending from one of the first face or the second face, the plurality of pins configured to space the one of the first face or the second face from contact surfaces of the adjacent components.

Non-destructive imaging of fragments of historical beeswax seals using high-contrast X-ray micro-radiography and micro-tomography with large area photon-counting detector array.

PubMed

Karch, Jakub; Bartl, Benjamin; Dudak, Jan; Zemlicka, Jan; Krejci, Frantisek

2016-12-01

Historical beeswax seals are unique cultural heritage objects. Unfortunately, a number of historical sealing waxes show a porous structure with a strong tendency to stratification and embrittlement, which makes these objects extremely prone to mechanical damage. The understanding of beeswax degradation processes therefore plays an important role in the preservation and consequent treatment of these objects. Conventional methods applied for the investigation of beeswax materials (e.g. gas chromatography) are of a destructive nature or bring only limited information about the sample surface (microscopic techniques). Considering practical limitations of conventional methods and ethical difficulties connected with the sampling of the historical material, radiation imaging methods such as X-ray micro-tomography presents a promising non-destructive tool for the onward scientific research in this field. In this contribution, we present the application of high-contrast X-ray micro-radiography and micro-tomography for the investigation of beeswax seal fragments. The method is based on the application of the large area photon-counting detector recently developed at our institute. The detector combines the advantages of single-photon counting technology with a large field of view. The method, consequently, enables imaging of relatively large objects with high geometrical magnification. In the reconstructed micro-tomographies of investigated historical beeswax seals, we are able to reveal morphological structures such as stratification, micro-cavities and micro-fractures with spatial resolution down to 5μm non-destructively and with high imaging quality. The presented work therefore demonstrates that a combination of state-of-the-art hybrid pixel semiconductor detectors and currently available micro-focus x-ray sources makes it possible to apply X-ray micro-radiography and micro-tomography as a valuable non-destructive tool for volumetric beeswax seal morphological studies. Copyright © 2016 Elsevier Ltd. All rights reserved.

Laboratory evaluation of the particle size effect on the performance of an elastomeric half-mask respirator against ultrafine combustion particles.

PubMed

He, Xinjian; Grinshpun, Sergey A; Reponen, Tiina; Yermakov, Michael; McKay, Roy; Haruta, Hiroki; Kimura, Kazushi

2013-08-01

This study quantified the particle size effect on the performance of elastomeric half-mask respirators, which are widely used by firefighters and first responders exposed to combustion aerosols. One type of elastomeric half-mask respirator equipped with two P-100 filters was donned on a breathing manikin while challenged with three combustion aerosols (originated by burning wood, paper, and plastic). Testing was conducted with respirators that were fully sealed, partially sealed (nose area only), or unsealed to the face of a breathing manikin to simulate different faceseal leakages. Three cyclic flows with mean inspiratory flow (MIF) rates of 30, 85, and 135 L/min were tested for each combination of sealing condition and combustion material. Additional testing was performed with plastic combustion particles at other cyclic and constant flows. Particle penetration was determined by measuring particle number concentrations inside and outside the respirator with size ranges from 20 to 200 nm. Breathing flow rate, particle size, and combustion material all had significant effects on the performance of the respirator. For the partially sealed and unsealed respirators, the penetration through the faceseal leakage reached maximum at particle sizes >100 nm when challenged with plastic aerosol, whereas no clear peaks were observed for wood and paper aerosols. The particles aerosolized by burning plastic penetrated more readily into the unsealed half-mask than those aerosolized by the combustion of wood and paper. The difference may be attributed to the fact that plastic combustion particles differ from wood and paper particles by physical characteristics such as charge, shape, and density. For the partially sealed respirator, the highest penetration values were obtained at MIF = 85 L/min. The unsealed respirator had approximately 10-fold greater penetration than the one partially sealed around the bridge of the nose, which indicates that the nose area was the primary leak site.

Expert system for identification of simultaneous and sequential reactor fuel failures with gas tagging

DOEpatents

Gross, Kenny C.

1994-01-01

Failure of a fuel element in a nuclear reactor core is determined by a gas tagging failure detection system and method. Failures are catalogued and characterized after the event so that samples of the reactor's cover gas are taken at regular intervals and analyzed by mass spectroscopy. Employing a first set of systematic heuristic rules which are applied in a transformed node space allows the number of node combinations which must be processed within a barycentric algorithm to be substantially reduced. A second set of heuristic rules treats the tag nodes of the most recent one or two leakers as "background" gases, further reducing the number of trial node combinations. Lastly, a "fuzzy" set theory formalism minimizes experimental uncertainties in the identification of the most likely volumes of tag gases. This approach allows for the identification of virtually any number of sequential leaks and up to five simultaneous gas leaks from fuel elements.

Heterogeneous Suppression of Sequential Effects in Random Sequence Generation, but Not in Operant Learning.

PubMed

Shteingart, Hanan; Loewenstein, Yonatan

2016-01-01

There is a long history of experiments in which participants are instructed to generate a long sequence of binary random numbers. The scope of this line of research has shifted over the years from identifying the basic psychological principles and/or the heuristics that lead to deviations from randomness, to one of predicting future choices. In this paper, we used generalized linear regression and the framework of Reinforcement Learning in order to address both points. In particular, we used logistic regression analysis in order to characterize the temporal sequence of participants' choices. Surprisingly, a population analysis indicated that the contribution of the most recent trial has only a weak effect on behavior, compared to more preceding trials, a result that seems irreconcilable with standard sequential effects that decay monotonously with the delay. However, when considering each participant separately, we found that the magnitudes of the sequential effect are a monotonous decreasing function of the delay, yet these individual sequential effects are largely averaged out in a population analysis because of heterogeneity. The substantial behavioral heterogeneity in this task is further demonstrated quantitatively by considering the predictive power of the model. We show that a heterogeneous model of sequential dependencies captures the structure available in random sequence generation. Finally, we show that the results of the logistic regression analysis can be interpreted in the framework of reinforcement learning, allowing us to compare the sequential effects in the random sequence generation task to those in an operant learning task. We show that in contrast to the random sequence generation task, sequential effects in operant learning are far more homogenous across the population. These results suggest that in the random sequence generation task, different participants adopt different cognitive strategies to suppress sequential dependencies when generating the "random" sequences.

Apparatus and process for microbial detection and enumeration

NASA Technical Reports Server (NTRS)

Wilkins, J. R.; Grana, D. (Inventor)

1982-01-01

An apparatus and process for detecting and enumerating specific microorganisms from large volume samples containing small numbers of the microorganisms is presented. The large volume samples are filtered through a membrane filter to concentrate the microorganisms. The filter is positioned between two absorbent pads and previously moistened with a growth medium for the microorganisms. A pair of electrodes are disposed against the filter and the pad electrode filter assembly is retained within a petri dish by retainer ring. The cover is positioned on base of petri dish and sealed at the edges by a parafilm seal prior to being electrically connected via connectors to a strip chart recorder for detecting and enumerating the microorganisms collected on filter.

Heartworm (Acanthocheilonema spirocauda) and seal louse (Echinophthirius horridus) infections in harbour seals (Phoca vitulina) from the North and Baltic Seas

NASA Astrophysics Data System (ADS)

Lehnert, Kristina; Schwanke, Eva; Hahn, Kerstin; Wohlsein, Peter; Siebert, Ursula

2016-07-01

The seal louse (Echinophthirius [E.] horridus) and the heartworm (Acanthocheilonema [A.] spirocauda) are parasites of harbour seal (Phoca vitulina). Little is known about the role of the seal louse as a potential vector and its role for the development and transmission of heartworm larvae to their final host, the harbour seal. The life-cycle of the heartworm is still not fully understood. For the presented study, findings of 1191 stranded harbour seals collected along the North- and Baltic Sea coast between 1996 and 2013 were examined. 4.4% (n = 53) of these harbour seals were infected with adult heartworms and 3.4% (n = 40) harbour seals carried seal lice. The highest prevalence and level of infection with adult heartworms (A. spirocauda) (9.3%) and seal lice (E. horridus) (8.9%) were found on yearling harbour seals (7-18 months) compared to neonate and adult seals. Investigating seal lice (n = 35) for larval heartworm stages one larvae was encountered in an ethanol-fixated seal louse. During a health monitoring survey of live harbour seals, 109 animals were captured and examined during spring and autumn between 2008 and 2014. Blood samples were taken and microfilariae were discovered in blood smears in 41% (n = 45) of the examined harbour seals. Yearling seals (n = 21) showed higher prevalence (86%) and level of infection with microfilariae than adults. Microfilariae were identified as A. spirocauda by sequencing the species-specific COI gene in 24 blood samples. The high prevalence of microfilariae of A. spirocauda in blood samples (41%) is in contrast to the low prevalence of mature infections/adult specimens in stranded seals (4.4%) investigated. Although rare parasites of seals, the recent increase in prevalence of heartworm and seal lice in stranded seals and the relatively high occurrence of microfilaria in the free-ranging population underscore the importance of further studies investigating the immunology of infections and their transmission pathways, as well as the epidemiology of both species.

A draft fur seal genome provides insights into factors affecting SNP validation and how to mitigate them.

PubMed

Humble, E; Martinez-Barrio, A; Forcada, J; Trathan, P N; Thorne, M A S; Hoffmann, M; Wolf, J B W; Hoffman, J I

2016-07-01

Custom genotyping arrays provide a flexible and accurate means of genotyping single nucleotide polymorphisms (SNPs) in a large number of individuals of essentially any organism. However, validation rates, defined as the proportion of putative SNPs that are verified to be polymorphic in a population, are often very low. A number of potential causes of assay failure have been identified, but none have been explored systematically. In particular, as SNPs are often developed from transcriptomes, parameters relating to the genomic context are rarely taken into account. Here, we assembled a draft Antarctic fur seal (Arctocephalus gazella) genome (assembly size: 2.41 Gb; scaffold/contig N50 : 3.1 Mb/27.5 kb). We then used this resource to map the probe sequences of 144 putative SNPs genotyped in 480 individuals. The number of probe-to-genome mappings and alignment length together explained almost a third of the variation in validation success, indicating that sequence uniqueness and proximity to intron-exon boundaries play an important role. The same pattern was found after mapping the probe sequences to the Walrus and Weddell seal genomes, suggesting that the genomes of species divergent by as much as 23 million years can hold information relevant to SNP validation outcomes. Additionally, reanalysis of genotyping data from seven previous studies found the same two variables to be significantly associated with SNP validation success across a variety of taxa. Finally, our study reveals considerable scope for validation rates to be improved, either by simply filtering for SNPs whose flanking sequences align uniquely and completely to a reference genome, or through predictive modelling. © 2015 John Wiley & Sons Ltd.

Hostile Thoracic Aortic Aneurysm Treated by Fenestrated Thoracic Stentgraft with Proximal Sealing in Ishimaru Zone 0.

PubMed

Sousa, Joel; Neves, João; Riambau, Vicente; Teixeira, José

2017-01-01

Thoracic endovascular aortic aneurysm repair (TEVAR) is an established treatment for thoracic aortic disease in both the acute and elective setting, with such a widespread use that almost 50% of all thoracic aortic surgery in Europe is performed by these means. Nonetheless, the feasibility of TEVAR is determined by several anatomic factors, and the suitability of the proximal and distal landing zones remain one of the main limitations to its use. The advent of custom-made thoracic stent grafts widened the endovascular options in some challenging anatomies. The authors present a case report of a descending thoracic aortic pseudo-aneurysm, with no suitable proximal landing zone, successfully treated by means of a custom- -made fenestrated thoracic stent graft. Male patient, 57 years old, with multiple cardiovascular risk factors and past medical history of coronary hearth disease, pulmonary emphysema and high speed trauma 20 years before. The patient was referred after being diagnosed with an asymptomatic saccular pseudo-aneurysm of the descending thoracic aorta, with 50mm of largest diameter and located at the level of the aortic isthmus. Inadequate proximal sealing was evident, even if deliberate left subclavian and carotid coverage were performed. Due to the prohibitive open surgical risk, and taking into account the post-traumatic etiology of the lesion, an endovascular solution was planned. The patient was therefore sequentially treated by means of a left carotid- subclavian bypass followed by custom-made fenestrated TEVAR, with a single fenestration for both the left common carotid artery and brachiocephalic trunk, granting proper sealing in the distal ascending aorta (Ishimaru zone 0). Rapid pacing was used during the implantation, with heart frequency of 180 bpm and systolic pressures of 40mmHg, allowing for a more precise deployment with no windsock effect. The procedure was successful and uneventful, with no intra-operative endoleaks, birdbeaks or retrograde dissections. There are no reported complications at 6 months follow-up. Custom-made fenestrated thoracic stentgrafts are an accessible, reproducible and safe therapeutic option when dealing with hostile thoracic arch anatomies, and should be considered as a minimally-invasive effective solution in selected cases.

Seal Joint Analysis and Design for the Ares-I Upper Stage LOX Tank

NASA Technical Reports Server (NTRS)

Phillips, Dawn R.; Wingate, Robert J.

2011-01-01

The sealing capability of the Ares-I Upper Stage liquid oxygen tank-to-sump joint is assessed by analyzing the deflections of the joint components. Analyses are performed using three-dimensional symmetric wedge finite element models and the ABAQUS commercial finite element software. For the pressure loads and feedline interface loads, the analyses employ a mixed factor of safety approach to comply with the Constellation Program factor of safety requirements. Naflex pressure-assisted seals are considered first because they have been used successfully in similar seal joints in the Space Shuttle External Tank. For the baseline sump seal joint configuration with a Naflex seal, the predicted joint opening greatly exceeds the seal design specification. Three redesign options of the joint that maintain the use of a Naflex seal are studied. The joint openings for the redesigned seal joints show improvement over the baseline configuration; however, these joint openings still exceed the seal design specification. RACO pressure-assisted seals are considered next because they are known to also be used on the Space Shuttle External Tank, and the joint opening allowable is much larger than the specification for the Naflex seals. The finite element models for the RACO seal analyses are created by modifying the models that were used for the Naflex seal analyses. The analyses show that the RACO seal may provide sufficient sealing capability for the sump seal joint. The results provide reasonable data to recommend the design change and plan a testing program to determine the capability of RACO seals in the Ares-I Upper Stage liquid oxygen tank sump seal joint.

[Sequential sampling plans to Orthezia praelonga Douglas (Hemiptera: Sternorrhyncha, Ortheziidae) in citrus].

PubMed

Costa, Marilia G; Barbosa, José C; Yamamoto, Pedro T

2007-01-01

The sequential sampling is characterized by using samples of variable sizes, and has the advantage of reducing sampling time and costs if compared to fixed-size sampling. To introduce an adequate management for orthezia, sequential sampling plans were developed for orchards under low and high infestation. Data were collected in Matão, SP, in commercial stands of the orange variety 'Pêra Rio', at five, nine and 15 years of age. Twenty samplings were performed in the whole area of each stand by observing the presence or absence of scales on plants, being plots comprised of ten plants. After observing that in all of the three stands the scale population was distributed according to the contagious model, fitting the Negative Binomial Distribution in most samplings, two sequential sampling plans were constructed according to the Sequential Likelihood Ratio Test (SLRT). To construct these plans an economic threshold of 2% was adopted and the type I and II error probabilities were fixed in alpha = beta = 0.10. Results showed that the maximum numbers of samples expected to determine control need were 172 and 76 samples for stands with low and high infestation, respectively.

Better together: reduced compliance after sequential versus simultaneous bilateral hearing aids fitting.

PubMed

Lavie, Limor; Banai, Karen; Attias, Joseph; Karni, Avi

2014-03-01

The purpose of this study was to determine the effects of sequential versus simultaneous bilateral hearing aids fitting on patient compliance. Thirty-six older adults with hearing impairment participated in this study. Twelve were fitted with bilateral hearing aids simultaneously. The remaining participants were fitted sequentially: One hearing aid (to the left or to the right ear) was used initially; 1 month later, the other ear was also fitted with a hearing aid for bilateral use. Self-reports on usefulness and compliance were elicited after the first and second months of hearing aid use. In addition, the number of hours the hearing aids were used was extracted from the data loggings of each device. Simultaneous fitting resulted in high levels of compliance and consistent usage throughout the study period. Sequential fitting resulted in abrupt reduction in compliance and hours of use once the second hearing aid was added, both in the clinical scoring and in the data loggings. Simultaneous fitting of bilateral hearing aids results in better compliance compared with sequential fitting. The addition of a second hearing aid after a relatively short period of monaural use may lead to inconsistent use of both hearing aids.

Reactivation, Replay, and Preplay: How It Might All Fit Together

PubMed Central

Buhry, Laure; Azizi, Amir H.; Cheng, Sen

2011-01-01

Sequential activation of neurons that occurs during “offline” states, such as sleep or awake rest, is correlated with neural sequences recorded during preceding exploration phases. This so-called reactivation, or replay, has been observed in a number of different brain regions such as the striatum, prefrontal cortex, primary visual cortex and, most prominently, the hippocampus. Reactivation largely co-occurs together with hippocampal sharp-waves/ripples, brief high-frequency bursts in the local field potential. Here, we first review the mounting evidence for the hypothesis that reactivation is the neural mechanism for memory consolidation during sleep. We then discuss recent results that suggest that offline sequential activity in the waking state might not be simple repetitions of previously experienced sequences. Some offline sequential activity occurs before animals are exposed to a novel environment for the first time, and some sequences activated offline correspond to trajectories never experienced by the animal. We propose a conceptual framework for the dynamics of offline sequential activity that can parsimoniously describe a broad spectrum of experimental results. These results point to a potentially broader role of offline sequential activity in cognitive functions such as maintenance of spatial representation, learning, or planning. PMID:21918724

A Bayesian sequential design with adaptive randomization for 2-sided hypothesis test.

PubMed

Yu, Qingzhao; Zhu, Lin; Zhu, Han

2017-11-01

Bayesian sequential and adaptive randomization designs are gaining popularity in clinical trials thanks to their potentials to reduce the number of required participants and save resources. We propose a Bayesian sequential design with adaptive randomization rates so as to more efficiently attribute newly recruited patients to different treatment arms. In this paper, we consider 2-arm clinical trials. Patients are allocated to the 2 arms with a randomization rate to achieve minimum variance for the test statistic. Algorithms are presented to calculate the optimal randomization rate, critical values, and power for the proposed design. Sensitivity analysis is implemented to check the influence on design by changing the prior distributions. Simulation studies are applied to compare the proposed method and traditional methods in terms of power and actual sample sizes. Simulations show that, when total sample size is fixed, the proposed design can obtain greater power and/or cost smaller actual sample size than the traditional Bayesian sequential design. Finally, we apply the proposed method to a real data set and compare the results with the Bayesian sequential design without adaptive randomization in terms of sample sizes. The proposed method can further reduce required sample size. Copyright © 2017 John Wiley & Sons, Ltd.

A Node Linkage Approach for Sequential Pattern Mining

PubMed Central

Navarro, Osvaldo; Cumplido, René; Villaseñor-Pineda, Luis; Feregrino-Uribe, Claudia; Carrasco-Ochoa, Jesús Ariel

2014-01-01

Sequential Pattern Mining is a widely addressed problem in data mining, with applications such as analyzing Web usage, examining purchase behavior, and text mining, among others. Nevertheless, with the dramatic increase in data volume, the current approaches prove inefficient when dealing with large input datasets, a large number of different symbols and low minimum supports. In this paper, we propose a new sequential pattern mining algorithm, which follows a pattern-growth scheme to discover sequential patterns. Unlike most pattern growth algorithms, our approach does not build a data structure to represent the input dataset, but instead accesses the required sequences through pseudo-projection databases, achieving better runtime and reducing memory requirements. Our algorithm traverses the search space in a depth-first fashion and only preserves in memory a pattern node linkage and the pseudo-projections required for the branch being explored at the time. Experimental results show that our new approach, the Node Linkage Depth-First Traversal algorithm (NLDFT), has better performance and scalability in comparison with state of the art algorithms. PMID:24933123

Self-regulated learning of important information under sequential and simultaneous encoding conditions.

PubMed

Middlebrooks, Catherine D; Castel, Alan D

2018-05-01

Learners make a number of decisions when attempting to study efficiently: they must choose which information to study, for how long to study it, and whether to restudy it later. The current experiments examine whether documented impairments to self-regulated learning when studying information sequentially, as opposed to simultaneously, extend to the learning of and memory for valuable information. In Experiment 1, participants studied lists of words ranging in value from 1-10 points sequentially or simultaneously at a preset presentation rate; in Experiment 2, study was self-paced and participants could choose to restudy. Although participants prioritized high-value over low-value information, irrespective of presentation, those who studied the items simultaneously demonstrated superior value-based prioritization with respect to recall, study selections, and self-pacing. The results of the present experiments support the theory that devising, maintaining, and executing efficient study agendas is inherently different under sequential formatting than simultaneous. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Experimental Research and Analysis of Rotordynamic Characteristics for a New Kind of Tilting-pad Gas Seal

NASA Astrophysics Data System (ADS)

Cao, Hao; Cao, Xiaoyu; Chen, Fei; Li, Ming; Zhang, Bolin; Wei, Jilong

2017-12-01

This paper presents a new kind of tilting-pad gas seal. This design is introduced to reduce the tangential seal force and to improve the stability of rotor system finally. A seal test rig is set up. The paper compares the leakage between tilting-pad seal and fixed pad seal. The result shows that the leakage ratio of the tilting-pad seal is close to the leakage ratio of the fixed pad seal. The work done by seal force on the cylinder system is calculated as an index of comparison between these two seals. Result shows that the work done by the fixed pad seal is greater than the work done by the tilting-pad seal. Moreover, system damping factor is used to compare the stabilities of these two seals. The impact tests on the cylinder system are done under different conditions. The system damping factors are calculated from the damped waves of system vibration. Test results show that the damping factor of the tilting pad seal is higher than that of the fixed pad seal in both the vertical and the horizontal directions.

40 CFR 61.275 - Periodic report.

Code of Federal Regulations, 2010 CFR

2010-07-01

... internal floating roof, or there are holes, tears or other openings in the seal or seal fabric; or (ii... has defects, the primary seal has holes, tears, or other openings in the seal or the seal fabric, or the secondary seal (if one has been installed) has holes, tears, or other openings in the seal or the...

Performance of a shaft seal system for the LE-7 rocket engine oxidizer turbopump

NASA Astrophysics Data System (ADS)

Oike, Mamoru; Nosaka, Masataka; Kikuchi, Masataka; Watanabe, Yoshiaki

An experimental study on a rotating-shaft seal system for a high-pressure liquid oxygen (LOX) turbopump has been conducted to develop the LE-7 engine for the Japanese H-II launch vehicle. The LOX turbopump rotating-shaft seal system, which prevents LOX (4.9 MPa) and the high-pressure turbine-drive gas (16.6 MPa, 970 K) from mixing during high-speed operations (18,000 to 20,000 rpm), consists of the following seals: an LOX seal comprising a floating-ring and a wear-ring, a turbine gas seal comprising two floating-rings, and a helium purge seal comprising two segmented circumferential seal-rings. This report describes experimental and observational results concerning the rotating-shaft seal system obtained in the LOX turbopump operations and the seal tests. Based on comparisons between the measurements and the analytical results, sealing characteristics of the seal system are discussed. Inspections of the sealing surfaces after the engine firing tests demonstrated that the LOX turbopump rotating-shaft seal system has sufficient durability for use in the LE-7 engine for the H-II launch vehicle.

Performance of the coned-face end seal with regard to energy conservation

NASA Technical Reports Server (NTRS)

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

1982-01-01

The effects of face coning on seal performance are evaluated with particular regard to the energy saving potential of convex conedface end seals as indicated by torque reduction. Experiments were conducted using a conventional carbon flat-face pusher-type seal, a coned-face pusher-type seal, coned-face bellows-type seal, and a modified coned-face pusher-type seal intended for dynamically unstable operation, with shaft rotation at up to 8000 rpm, pressures of up to 2758 kPa, and a petroleum-based turbine oil as lubricant. Torque at the seal interface is found to be reduced by 42% when the standard flat-face seal is replaced by a coned seal, although the leakage of the cone-face seal was 11 times greater. Reduction of seal balance from 76.1 to 51.3% resulted in an additional 44% reduction in torque, although at the expense of excessive leakage, but did not produce unstable operation. Face temperatures were reduced by 33-56 C and wear was also reduced greatly on the cone face seals. Seal performance is noted to be in agreement with analytical calculations.

X-38 Seal Development

NASA Technical Reports Server (NTRS)

Curry, Donald M.; Lewis, Ronald K.; Hagen, Jeffrey D.

2002-01-01

An X-38 Crew Return Vehicle Seal Development is presented. The contents include: 1) X-38 Crew Return Vehicle; 2) X-38 TPS Configuration; 3) X-38 Seal Locations; 4) X-38 Rudder/Fin Seal Assembly; 5) Baseline X-38 Rudder/Fin Seal Design; 6) Rudder/Fin Seal to Bracket Assembly; 7) X-38 Rudder/Fin Vertical Rub Surface Inconel-0.10 inches; 8) X-38 Rudder/Fin Seal Analysis; 9) Seal Analysis Model; and 10) Governing Differential Equations for Equilibrium Thermal Assumption. The X-38 Rudder/Fin Seal temperature and pressure properties are also given.

Integrated seal for high-temperature electrochemical device

DOEpatents

Tucker, Michael C; Jacobson, Craig P

2013-07-16

The present invention provides electrochemical device structures having integrated seals, and methods of fabricating them. According to various embodiments the structures include a thin, supported electrolyte film with the electrolyte sealed to the support. The perimeter of the support is self-sealed during fabrication. The perimeter can then be independently sealed to a manifold or other device, e.g., via an external seal. According to various embodiments, the external seal does not contact the electrolyte, thereby eliminating the restrictions on the sealing method and materials imposed by sealing against the electrolyte.

Spring loaded compliant seal for high temperature use

DOEpatents

Memmen, Robert L; Fedock, John A; Downs, James P

2013-10-15

A flexible seal having an X-shaped cross section that forms four contact points on four contact surfaces of two opposed seal slots. The flexible seal is used for a component in which the two seal slots undergo a large deflection such that the opposed slots are not aligned and a rigid seal will not form an adequate seal. The flexible seal can be used in a component of a combustor or a turbine in a gas turbine engine where opposed seal slots undergo the large deflection during operation.

Dynamic response of film thickness in spiral-groove face seals

NASA Technical Reports Server (NTRS)

Dirusso, E.

1985-01-01

Tests were performed on an inward- and an outward-pumping spiral-groove face seal to experimentally determine the film thickness response to seal seat motions and to gain insight into the effect of secondary seal friction on film thickness behavior. Film thickness, seal seat axial motion, seal frictional torque, and film axial load were recorded as functions of time. The experiments revealed that for sinusoidal axial oscillations of the seal seat, the primary ring followed the seal seat motion very well. For a skewed seal seat, however, the primary ring did not follow the seal seat motion, and load-carrying capacity was degraded. Secondary seal friction was varied over a wide range to determine its effect on film thickness dynamics. The seals were tested with ambient air at room temperature and atmospheric pressure as the fluid medium. The test speed ranged from 7000 to 20,000 rpm. Seal tangential velocity ranged from 34 to 98 m/sec (113 to 323 ft/sec).

Toward an Improved Hypersonic Engine Seal

NASA Technical Reports Server (NTRS)

Dunlap, Patrick H., Jr.; Steinetz, Bruce M.; DeMange,Jeffrey J.; Taylor, Shawn C.

2003-01-01

High temperature, dynamic seals are required in advanced engines to seal the perimeters of movable engine ramps for efficient, safe operation in high heat flux environments at temperatures from 2000 to 2500 F. Current seal designs do not meet the demanding requirements for future engines, so NASA s Glenn Research Center (GRC) is developing advanced seals to overcome these shortfalls. Two seal designs and two types of seal preloading devices were evaluated in a series of compression tests at room temperature and 2000 F and flow tests at room temperature. Both seals lost resiliency with repeated load cycling at room temperature and 2000 F, but seals with braided cores were significantly more flexible than those with cores composed of uniaxial ceramic fibers. Flow rates for the seals with cores of uniaxial fibers were lower than those for the seals with braided cores. Canted coil springs and silicon nitride compression springs showed promise conceptually as potential seal preloading devices to help maintain seal resiliency.

A fast and accurate online sequential learning algorithm for feedforward networks.

PubMed

Liang, Nan-Ying; Huang, Guang-Bin; Saratchandran, P; Sundararajan, N

2006-11-01

In this paper, we develop an online sequential learning algorithm for single hidden layer feedforward networks (SLFNs) with additive or radial basis function (RBF) hidden nodes in a unified framework. The algorithm is referred to as online sequential extreme learning machine (OS-ELM) and can learn data one-by-one or chunk-by-chunk (a block of data) with fixed or varying chunk size. The activation functions for additive nodes in OS-ELM can be any bounded nonconstant piecewise continuous functions and the activation functions for RBF nodes can be any integrable piecewise continuous functions. In OS-ELM, the parameters of hidden nodes (the input weights and biases of additive nodes or the centers and impact factors of RBF nodes) are randomly selected and the output weights are analytically determined based on the sequentially arriving data. The algorithm uses the ideas of ELM of Huang et al. developed for batch learning which has been shown to be extremely fast with generalization performance better than other batch training methods. Apart from selecting the number of hidden nodes, no other control parameters have to be manually chosen. Detailed performance comparison of OS-ELM is done with other popular sequential learning algorithms on benchmark problems drawn from the regression, classification and time series prediction areas. The results show that the OS-ELM is faster than the other sequential algorithms and produces better generalization performance.

Industrial Computer Codes

NASA Technical Reports Server (NTRS)

Shapiro, Wilbur

1996-01-01

This is an overview of new and updated industrial codes for seal design and testing. GCYLT (gas cylindrical seals -- turbulent), SPIRALI (spiral-groove seals -- incompressible), KTK (knife to knife) Labyrinth Seal Code, and DYSEAL (dynamic seal analysis) are covered. CGYLT uses G-factors for Poiseuille and Couette turbulence coefficients. SPIRALI is updated to include turbulence and inertia, but maintains the narrow groove theory. KTK labyrinth seal code handles straight or stepped seals. And DYSEAL provides dynamics for the seal geometry.

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

PubMed

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.

Closure head for a nuclear reactor

DOEpatents

Wade, Elman E.

1980-01-01

A closure head for a nuclear reactor includes a stationary outer ring integral with the reactor vessel with a first rotatable plug disposed within the stationary outer ring and supported from the stationary outer ring by a bearing assembly. A sealing system is associated with the bearing assembly to seal the annulus defined between the first rotatable plug and the stationary outer ring. The sealing system comprises tubular seal elements disposed in the annulus with load springs contacting the tubular seal elements so as to force the tubular seal elements against the annulus in a manner to seal the annulus. The sealing system also comprises a sealing fluid which is pumped through the annulus and over the tubular seal elements causing the load springs to compress thereby reducing the friction between the tubular seal elements and the rotatable components while maintaining a gas-tight seal therebetween.

Rim seal arrangement having pumping feature

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Ching-Pang; Myers, Caleb

A rim seal arrangement for a gas turbine engine includes a first seal face on a rotor component, and a second seal face on a stationary annular rim centered about a rotation axis of the rotor component. The second seal face is spaced from the first seal face along an axial direction to define a seal gap. The seal gap is located between a radially outer hot gas path and a radially inner rotor cavity. The first seal face has a plurality of circumferentially spaced depressions, each having a depth in an axial direction and extending along a radial extentmore » of the first seal face. The depressions influence flow in the seal gap such that during rotation of the rotor component, fluid in the seal gap is pumped in a radially outward direction to prevent ingestion of a gas path fluid from the hot gas path into the rotor cavity.« less

Baxter Community—High Performance Green Building

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2009-02-16

This case study describes the Baxter community built by David Weekley Homes, which is reducing their energy demand through a number of techniques including advanced air sealing techniques, the installation of SEER 14 air conditioners, and Low-e windows in conjunction with conventional framing and insulation.

78 FR 25097 - Notice of Realty Action: Competitive, Sealed-Bid, Spring SNPLMA Sale of Public Lands in Clark...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-29

... Determination of National Environmental Policy Act Adequacy (DNA). DATES: Interested parties may submit written... December 23, 2004, and a site specific DNA document numbered DOI-BLM-NV-S010-2012-0106-DNA. Sale procedures...

Improvements of vacuum system in J-PARC 3 GeV synchrotron

NASA Astrophysics Data System (ADS)

Kamiya, J.; Hikichi, Y.; Namekawa, Y.; Takeishi, K.; Yanagibashi, T.; Kinsho, M.; Yamamoto, K.; Sato, A.

2017-07-01

The RCS vacuum system has been upgraded since the completion of its construction towards the objectives of both better vacuum quality and higher reliability of the components. For the better vacuum quality, (1) pressure of the injection beam line was improved to prevent the H-beam from converting to H0; (2) leakage in the beam injection area due to the thermal expansion was eliminated by applying the adequate torque amount for the clamps; (3) new in-situ degassing method of the kicker magnet was developed. For the reliability increase of the components, (1) A considerable number of fluoroelastmer seal was exchanged to metal seal with the low spring constant bellows and the light clamps; (2) TMP controller for the long cable was developed to prevent the controller failure by the severe electrical noise; (3) A number of TMP were installed instead of ion pumps in the RF cavity section as an insurance for the case of pump trouble.

Coaxial twin-shaft magnetic fluid seals applied in vacuum wafer-handling robot

NASA Astrophysics Data System (ADS)

Cong, Ming; Wen, Haiying; Du, Yu; Dai, Penglei

2012-07-01

Compared with traditional mechanical seals, magnetic fluid seals have unique characters of high airtightness, minimal friction torque requirements, pollution-free and long life-span, widely used in vacuum robots. With the rapid development of Integrate Circuit (IC), there is a stringent requirement for sealing wafer-handling robots when working in a vacuum environment. The parameters of magnetic fluid seals structure is very important in the vacuum robot design. This paper gives a magnetic fluid seal device for the robot. Firstly, the seal differential pressure formulas of magnetic fluid seal are deduced according to the theory of ferrohydrodynamics, which indicate that the magnetic field gradient in the sealing gap determines the seal capacity of magnetic fluid seal. Secondly, the magnetic analysis model of twin-shaft magnetic fluid seals structure is established. By analyzing the magnetic field distribution of dual magnetic fluid seal, the optimal value ranges of important parameters, including parameters of the permanent magnetic ring, the magnetic pole tooth, the outer shaft, the outer shaft sleeve and the axial relative position of two permanent magnetic rings, which affect the seal differential pressure, are obtained. A wafer-handling robot equipped with coaxial twin-shaft magnetic fluid rotary seals and bellows seal is devised and an optimized twin-shaft magnetic fluid seals experimental platform is built. Test result shows that when the speed of the two rotational shafts ranges from 0-500 r/min, the maximum burst pressure is about 0.24 MPa. Magnetic fluid rotary seals can provide satisfactory performance in the application of wafer-handling robot. The proposed coaxial twin-shaft magnetic fluid rotary seal provides the instruction to design high-speed vacuum robot.

A ferrofluidic seal specially designed for rotary blood pumps.

PubMed

Mitamura, Y; Fujiyoshi, M; Yoshida, T; Yozu, R; Okamoto, E; Tanaka, T; Kawada, S

1996-06-01

One of the key technologies required for rotary blood pumps is sealing of the motor shaft. A ferrofluidic seal was developed for an axial flow pump. The seal body was composed of a plastic magnet and two pole pieces. This seal was formed by injecting ferrofluid into the gap between the pole pieces and the motor shaft. To contain the ferrofluid in the seal and to minimize the possibility of ferrofluid making contact with blood, a shield with a small cavity was provided on the pole piece. Sealing pressure of the seal was measured. The sealing pressure was maintained at more than 23.3 kPa (175 mm Hg) for a motor speed up to 11,000 rpm. The specially designed ferrofluidic seal for sealing out liquids is useful for axial flow blood pumps.

Contracting/expanding self-sealing cryogenic tube seals

NASA Technical Reports Server (NTRS)

Jia, Lin X. (Inventor)

1997-01-01

Contracting/expanding self-sealing cryogenic tube seals are disclosed which use the different properties of thermal contraction and expansion of selected dissimilar materials in accord with certain design criteria to yield self-tightening seals via sloped-surface sealing. The seals of the subject invention are reusable, simple to assemble, and adaptable to a wide variety of cryogenic applications.

Contracting/expanding self-sealing cryogenic tube seals

NASA Technical Reports Server (NTRS)

Jia, Lin X. (Inventor)

1997-01-01

Contracting/expanding self-sealing cryogenic tube seals are disclosed which use the different properties of thermal contraction and expansion of selected dissimilar materials in accord with certain design criteria to yield self-tightening seals via sloped-surface sealing. The seals of the subject invention are reusable, simple to assemble, adaptable to a wide variety of cryogenic applications.

Optical and UV Sensing Sealed Tube Microchannel Plate Imaging Detectors with High Time Resolution

NASA Astrophysics Data System (ADS)

Siegmund, O.; Vallerga, J.; Tremsin, A.; Hull, J.; Elam, J.; Mane, A.

2014-09-01

Microchannel plate (MCP) based imaging, photon time tagging detector sealed tube schemes have a unique set of operational features that enable high time resolution astronomical and remote sensing applications to be addressed. New detectors using the cross strip (XS), cross delay line (XDL), or stripline anode readouts, a wide range of photocathode types, and advanced MCP technologies have been implemented to improve many performance characteristics. A variety of sealed tubes have been developed including 18mm XS readout devices with GaAs and SuperGenII photocathodes, 25mm XDL readout devices with SuperGenII and GaN photocathodes, and 20 x 20 cm sealed tubes with bialkali photocathodes and strip line readout. One key technology that has just become viable is the ability to make MCPs using atomic layer deposition (ALD) techniques. This employs nanofabrication of the active layers of an MCP on a microcapillary array. This technique opens new performance opportunities, including, very large MCP areas (>20cm), very low intrinsic background, lower radiation induced background, much longer overall lifetime and gain stability, and markedly lower outgassing which can improve the sealed tube lifetime and ease of fabrication. The XS readout has been implemented in formats of 22mm, 50mm and 100mm, and uses MCP charge signals detected on two orthogonal layers of conductive fingers to encode event X-Y positions. We have achieved spatial resolution XS detectors better than 25 microns FWHM, with good image linearity while at low gain (<10^6), substantially increasing local counting rate capabilities and the overall tube lifetime. XS tubes with updated electronics can encode event rates of >5 MHz with ~12% dead time and event timing accuracy of ~100ps. XDL sealed tubes in 25mm format demonstrate ~40 micron spatial resolution at up to ~2 MHz event rates, and have been developed with SupergenII visible regime photocathodes. The XDL tubes also achieve ~100 ps time resolution. Most recently ALD MCPs with an opaque GaN photocathode (100-350nm range) on the MCP surface has been demonstrated in a sealed tube configuration. These ALD MCPs show a stable and permanent 10x gain increase during tube processing. Efforts are also underway to establish ALD MCP configurations with large area sealed tubes from 5cm up to 20cm in size. We will discuss these efforts and their performance characteristics. We will discuss how we are applying these detector system developments to a number of applications. This includes ground based instruments for observations of transient and variable astronomical objects, as well as implementation in satellite instruments for earth atmospheric and solar observations. The XS 18mm sealed tube detectors are being implemented for night time remote reconnaissance and biological single-molecule fluorescence lifetime imaging microscopy. Related efforts also include development of large (20cm) sealed tubes for Cherenkov light detection and large area focal plane imagers, and GaN sealed tube devices are candidates for future astronomical space based UV imaging and spectroscopy.

Immunosuppression in harbour seals fed fish from the contaminated Baltic Sea

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ross, P.S.; Swart, R.L. de; Timmerman, H.H.

Environmental contaminants including dioxins and polychlorinated biphenyls have been shown to be immunotoxic in laboratory animals, but little information exists as to their possible effect on mammals in the natural environment. Recent virus-induced mass mortalities among marine mammals occupying high trophic levels have led to much speculation regarding a possible contributory role of pollutants in these events. The authors undertook a two-year captive feeding experiment with harbor seals, Phoca vitulina, where one group was fed herring from the contaminated Baltic Sea and a second group was fed relatively uncontaminated herring from the Atlantic Ocean. During the course of the experiment,more » they regularly sampled blood and undertook a series of immune function tests. They observed a significant impairment of natural killer cell activity and T-lymphocyte function, in vitro, in the group of seals fed the Baltic Sea fish. In addition, seals of this group were less able to mount a specific humoral and delayed type hypersensitivity response to a protein antigen, ovalbumin, upon immunization. Increased numbers of granulocytes in this group may have reflected periodic bacterial infections as a consequence of impaired immune function. Their results suggest that pollutants accumulated through the food chain in contaminated marine waters may suppress normal immune responses in marine mammals and lead to an increased susceptibility to opportunistic infection.« less

Foraging-Based Enrichment Promotes More Varied Behaviour in Captive Australian Fur Seals (Arctocephalus pusillus doriferus)

PubMed Central

Hocking, David P.; Salverson, Marcia; Evans, Alistair R.

2015-01-01

During wild foraging, Australian fur seals (Arctocephalus pusillus doriferus) encounter many different types of prey in a wide range of scenarios, yet in captive environments they are typically provided with a narrower range of opportunities to display their full repertoire of behaviours. This study aimed to quantitatively explore the effect of foraging-based enrichment on the behaviour and activity patterns displayed by two captive Australian fur seals at Melbourne Zoo, Australia. Food was presented as a scatter in open water, in a free-floating ball device, or in a static box device, with each treatment separated by control trials with no enrichment. Both subjects spent more time interacting with the ball and static box devices than the scatter feed. The total time spent pattern swimming was reduced in the enrichment treatments compared to the controls, while the time spent performing random swimming behaviours increased. There was also a significant increase in the total number of bouts of behaviour performed in all three enrichment treatments compared to controls. Each enrichment method also promoted a different suit of foraging behaviours. Hence, rather than choosing one method, the most effective way to increase the diversity of foraging behaviours, while also increasing variation in general activity patterns, is to provide seals with a wide range of foraging scenarios where food is encountered in different ways. PMID:25946412

Water-soluble vitamin homeostasis in fasting northern elephant seals (Mirounga angustirostris) measured by metabolomics analysis and standard methods.

PubMed

Boaz, Segal M; Champagne, Cory D; Fowler, Melinda A; Houser, Dorian H; Crocker, Daniel E

2012-02-01

Despite the importance of water-soluble vitamins to metabolism, there is limited knowledge of their serum availability in fasting wildlife. We evaluated changes in water-soluble vitamins in northern elephant seals, a species with an exceptional ability to withstand nutrient deprivation. We used a metabolomics approach to measure vitamins and associated metabolites under extended natural fasts for up to 7 weeks in free-ranging lactating or developing seals. Water-soluble vitamins were not detected with this metabolomics platform, but could be measured with standard assays. Concentrations of measured vitamins varied independently, but all were maintained at detectable levels over extended fasts, suggesting that defense of vitamin levels is a component of fasting adaptation in the seals. Metabolomics was not ideal for generating complete vitamin profiles in this species, but gave novel insights into vitamin metabolism by detecting key related metabolites. For example, niacin level reductions in lactating females were associated with significant reductions in precursors suggesting downregulation of the niacin synthetic pathway. The ability to detect individual vitamins using metabolomics may be impacted by the large number of novel compounds detected. Modifications to the analysis platforms and compound detection algorithms used in this study may be required for improving water-soluble vitamin detection in this and other novel wildlife systems. Copyright © 2011 Elsevier Inc. All rights reserved.

Advanced Seal Development for Large Industrial Gas Turbines

NASA Technical Reports Server (NTRS)

Chupp, Raymond E.

2006-01-01

Efforts are in progress to develop advanced sealing for large utility industrial gas turbine engines (combustion turbines). Such seals have been under developed for some time for aero gas turbines. It is desired to transition this technology to combustion turbines. Brush seals, film riding face and circumferential seals, and other dynamic and static sealing approaches are being incorporated into gas turbines for aero applications by several engine manufacturers. These seals replace labyrinth or other seals with significantly reduced leakage rates. For utility industrial gas turbines, leakage reduction with advanced sealing can be even greater with the enormous size of the components. Challenges to transitioning technology include: extremely long operating times between overhauls; infrequent but large radial and axial excursions; difficulty in coating larger components; and maintenance, installation, and durability requirements. Advanced sealing is part of the Advanced Turbine Systems (ATS) engine development being done under a cooperative agreement between Westinghouse and the US Department of Energy, Office of Fossil Energy. Seal development focuses on various types of seals in the 501ATS engine both at dynamic and static locations. Each development includes rig testing of candidate designs and subsequent engine validation testing of prototype seals. This presentation gives an update of the ongoing ATS sealing efforts with special emphasis on brush seals.

Microwave Ablation: Comparison of Simultaneous and Sequential Activation of Multiple Antennas in Liver Model Systems

PubMed Central

Harari, Colin M.; Magagna, Michelle; Bedoya, Mariajose; Lee, Fred T.; Lubner, Meghan G.; Hinshaw, J. Louis; Ziemlewicz, Timothy

2016-01-01

Purpose To compare microwave ablation zones created by using sequential or simultaneous power delivery in ex vivo and in vivo liver tissue. Materials and Methods All procedures were approved by the institutional animal care and use committee. Microwave ablations were performed in both ex vivo and in vivo liver models with a 2.45-GHz system capable of powering up to three antennas simultaneously. Two- and three-antenna arrays were evaluated in each model. Sequential and simultaneous ablations were created by delivering power (50 W ex vivo, 65 W in vivo) for 5 minutes per antenna (10 and 15 minutes total ablation time for sequential ablations, 5 minutes for simultaneous ablations). Thirty-two ablations were performed in ex vivo bovine livers (eight per group) and 28 in the livers of eight swine in vivo (seven per group). Ablation zone size and circularity metrics were determined from ablations excised postmortem. Mixed effects modeling was used to evaluate the influence of power delivery, number of antennas, and tissue type. Results On average, ablations created by using the simultaneous power delivery technique were larger than those with the sequential technique (P < .05). Simultaneous ablations were also more circular than sequential ablations (P = .0001). Larger and more circular ablations were achieved with three antennas compared with two antennas (P < .05). Ablations were generally smaller in vivo compared with ex vivo. Conclusion The use of multiple antennas and simultaneous power delivery creates larger, more confluent ablations with greater temperatures than those created with sequential power delivery. © RSNA, 2015 PMID:26133361

Growth Kinematics of Opening-Mode Fractures

NASA Astrophysics Data System (ADS)

Eichhubl, P.; Alzayer, Y.; Laubach, S.; Fall, A.

2014-12-01

Fracture aperture is a primary control on flow in fractured reservoirs of low matrix permeability including unconventional oil and gas reservoirs and most geothermal systems. Guided by principles of linear elastic fracture mechanics, fracture aperture is generally assumed to be a linear function of fracture length and elastic material properties. Natural opening-mode fractures with significant preserved aperture are observed in core and outcrop indicative of fracture opening strain accommodated by permanent solution-precipitation creep. Fracture opening may thus be decoupled from length growth if the material effectively weakens after initial elastic fracture growth by either non-elastic deformation processes or changes in elastic properties. To investigate the kinematics of fracture length and aperture growth, we reconstructed the opening history of three opening-mode fractures that are bridged by crack-seal quartz cement in Travis Peak Sandstone of the SFOT-1 well, East Texas. Similar crack-seal cement bridges had been interpreted to form by repeated incremental fracture opening and subsequent precipitation of quartz cement. We imaged crack-seal cement textures for bridges sampled at varying distance from the tips using scanning electron microscope cathodoluminescence, and determined the number and thickness of crack-seal cement increments as a function of position along the fracture length and height. Observed trends in increment number and thickness are consistent with an initial stage of fast fracture propagation relative to aperture growth, followed by a stage of slow propagation and pronounced aperture growth. Consistent with fluid inclusion observations indicative of fracture opening and propagation occurring over 30-40 m.y., we interpret the second phase of pronounced aperture growth to result from fracture opening strain accommodated by solution-precipitation creep and concurrent slow, possibly subcritical, fracture propagation. Similar deformation mechanisms are envisioned to govern fracture growth over shorter timescales in reactive chemical subsurface environments including CO2 reservoirs, organic-rich shales, and geothermal systems.

A magnetic fluid seal for rotary blood pumps: Behaviors of magnetic fluids in a magnetic fluid seal.

PubMed

Mitamura, Yoshinori; Yano, Tetsuya; Nakamura, Wataru; Okamoto, Eiji

2013-01-01

A magnetic fluid (MF) seal has excellent durability. The performance of an MF seal, however, has been reported to decrease in liquids (several days). We have developed an MF seal that has a shield mechanism. The seal was perfect for 275 days in water. To investigate the effect of a shield, behaviors of MFs in a seal in water were studied both experimentally and computationally. (a) Two kinds of MF seals, one with a shield and one without a shield, were installed in a centrifugal pump. Behaviors of MFs in the seals in water were observed with a video camera and high-speed microscope. In the seal without a shield, the surface of the water in the seal waved and the turbulent flow affected behaviors of the MFs. In contrast, MFs rotated stably in the seal with a shield in water even at high rotational speeds. (b) Computational fluid dynamics analysis revealed that a stationary secondary flow pattern in the seal and small velocity difference between magnetic fluid and water at the interface. These MF behaviors prolonged the life of an MF seal in water.

Stabilizing geometry for hydrodynamic rotary seals

DOEpatents

Dietle, Lannie L.; Schroeder, John E.

2010-08-10

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

A Ferrofluidic Seal Specially Designed for Rotary Blood Pumps.

PubMed

Mitamura, Yoshinori; Fujiyoshi, Masayoshi; Yoshida, Toshiobu; Yozu, Ryohei; Okamoto, Eiji; Tanaka, Takashi; Kawada, Shiaki

1996-05-01

One of the key technologies required for rotary blood pumps is sealing of the motor shaft. A ferrofluidic seal was developed for an axial flow pump. The seal body was composed of a plastic magnet and two pole pieces. This seal was formed by injecting ferrofluid into the gap between the pole pieces and the motor shaft. To contain the ferrofluid in the seal and to minimize the possibility of ferrofluid making contact with blood, a shield with a small cavity was provided on the pole piece. Sealing pressure of the seal was measured. The sealing pressure was maintained at more than 23.3 kPa (175 mm Hg) for a motor speed up to 11,000 rpm. The specially designed ferrofluidic seal for sealing out liquids is useful for axial flow blood pumps. © 1996 International Society for Artificial Organs.

Mechanical seal assembly

DOEpatents

Kotlyar, Oleg M.

2001-01-01

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

Mechanical seal assembly

DOEpatents

Kotlyar, Oleg M.

2002-01-01

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

Emergency sacrificial sealing method in filters, equipment, or systems

DOEpatents

Brown, Erik P

2014-09-30

A system seals a filter or equipment component to a base and will continue to seal the filter or equipment component to the base in the event of hot air or fire. The system includes a first sealing material between the filter or equipment component and the base; and a second sealing material between the filter or equipment component and the base and proximate the first sealing material. The first sealing material and the second seal material are positioned relative to each other and relative to the filter or equipment component and the base to seal the filter or equipment component to the base and upon the event of fire the second sealing material will be activated and expand to continue to seal the filter or equipment component to the base in the event of hot air or fire.

Turbine blade platform seal

DOEpatents

Zagar, Thomas W.; Schiavo, Anthony L.

2001-01-01

A rotating blade group 90 for a turbo-machine having an improved device for sealing the gap 110 between the edges 112,114 of adjacent blade platforms 96,104. The gap 110 between adjacent blades 92,100 is sealed by a seal pin 20 its central portion 110 and by a seal plate 58,60 at each of the front 54 and rear 56 portions. The seal plates 58,60 are inserted into corresponding grooves 62,64 formed in the adjacent edges 112,114 of adjoining blades 92,100 and held in place by end plates 40,42. The end of the seal plates 58,60 may be chamfered 78,80 to improve the seal against the end plate 40,42. The seal pin 20 provides the required damping between the blades 92,100 and the seal plates 58,60 provide improved sealing effectiveness.

Seals Research at AlliedSignal

NASA Technical Reports Server (NTRS)

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.

The Condition of Education 2010 in Brief. NCES 2010-029

ERIC Educational Resources Information Center

Aud, Susan, Ed.; Hannes, Gretchen, Ed.

2010-01-01

This publication contains a sample of the indicators in "The Condition of Education 2010." The indicators in this publication are numbered sequentially, rather than according to their numbers in the complete edition. Since 1870, the federal government has gathered data about students, teachers, schools, and education funding. As mandated…

14 CFR Sec. 1-4 - System of accounts coding.

Code of Federal Regulations, 2010 CFR

2010-01-01

... General Accounting Provisions Sec. 1-4 System of accounts coding. (a) A four digit control number is assigned for each balance sheet and profit and loss account. Each balance sheet account is numbered sequentially, within blocks, designating basic balance sheet classifications. The first two digits of the four...

A Human Rights Perspective of Assisted Suicide: Accounting for Disparate Jurisprudence.

PubMed

Martin, Stevie S

2018-02-01

This article critically examines the decision of the New Zealand High Court in Seales v Attorney-General [2015] NZHC 1239, which rejected the claim that that country's blanket ban on assisted suicide violated various rights enshrined in the New Zealand Bill of Rights. That outcome runs contrary to the Canadian Supreme Court's decision in Carter v Canada (Attorney General) [2015] 1 SCR 331. This disparity in result arose despite overt similarities between the rights documents in each of the jurisdictions and, more significantly, notwithstanding the fact that the trial judge in Seales placed heavy reliance upon the decision in Carter. With two new challenges to the blanket ban on assisted suicide in England and Wales progressing through the lower courts, and given proposed amendments to the ban in both New Zealand and its antipodean neighbours - the Australian states of Victoria and New South Wales - it is a propitious time to consider the reasons for the disparate outcomes in Seales and Carter. This article will demonstrate that the trial judge's reasoning in Seales was wanting in a number of important respects, particularly in terms of the characterisation of the objective of the blanket ban. These limitations undermine the decision's utility as authority both domestically and internationally. This is particularly important given the high likelihood that reference will be made to the decision during debate in the New Zealand Parliament regarding amendments to the ban in that country and the possibility that the Legislatures in Victoria and New South Wales, as well as the English courts hearing the current challenges to the ban in that jurisdiction will, particularly given the shared common law background, refer to the judgment in Seales.

Controlled-force end seal arrangement for an air press of a papermaking machine

DOEpatents

Beck, David A.

2003-07-08

An air press for pressing a fiber web includes a plurality of rolls and a pair of end seal arrangements. Of the plurality of rolls, each pair of adjacent rolls forms a nip therebetween. Further, each roll has a pair of roll ends, the plurality of rolls together forming two sets of roll ends. Each end seal arrangement coacts with one set of roll ends, the plurality of rolls and the pair of end seal arrangements together defining an air press chamber having an air chamber pressure. Each end seal arrangement is composed of at least one roll seal, including a first roll seal, and an adjustable bias mechanism. Each roll seal forms a seal with at least one roll end, and one side of the first roll seal being exposed to the air chamber pressure. The adjustable bias mechanism is configured for controlling a position of each roll seal relative to a respective at least one roll end and for adjusting a seal force between the roll seal and the respective at least one roll end.

Sequential Multiplex Analyte Capturing for Phosphoprotein Profiling*

PubMed Central

Poetz, Oliver; Henzler, Tanja; Hartmann, Michael; Kazmaier, Cornelia; Templin, Markus F.; Herget, Thomas; Joos, Thomas O.

2010-01-01

Microarray-based sandwich immunoassays can simultaneously detect dozens of proteins. However, their use in quantifying large numbers of proteins is hampered by cross-reactivity and incompatibilities caused by the immunoassays themselves. Sequential multiplex analyte capturing addresses these problems by repeatedly probing the same sample with different sets of antibody-coated, magnetic suspension bead arrays. As a miniaturized immunoassay format, suspension bead array-based assays fulfill the criteria of the ambient analyte theory, and our experiments reveal that the analyte concentrations are not significantly changed. The value of sequential multiplex analyte capturing was demonstrated by probing tumor cell line lysates for the abundance of seven different receptor tyrosine kinases and their degree of phosphorylation and by measuring the complex phosphorylation pattern of the epidermal growth factor receptor in the same sample from the same cavity. PMID:20682761

Development of Advanced Seals for Industrial Turbine Applications

NASA Astrophysics Data System (ADS)

Chupp, Raymond E.; Aksit, Mahmut F.; Ghasripoor, Farshad; Turnquist, Norman A.; Dinc, Saim; Mortzheim, Jason; Demiroglu, Mehmet

2002-10-01

A critical area being addressed to improve industrial turbine performance is reducing the parasitic leakage flows through the various static and dynamic seals. Implementation of advanced seals into General Electric (GE) industrial turbines has progressed well over the last few years with significant operating performance gains achieved. Advanced static seals have been placed in gas turbine hot gas-path junctions and steam turbine packing ring segment end gaps. Brush seals have significantly decreased labyrinth seal leakages in gas turbine compressors and turbine interstages, steam turbine interstage and end packings, industrial compressor shaft seals, and generator seals. Abradable seals are being developed for blade-tip locations in various turbine locations. This presentation summarizes the status of advanced seal development for industrial turbines at GE.

Method and system to facilitate sealing in gas turbines

DOEpatents

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.

Mechanical seal having a single-piece, perforated mating ring

DOEpatents

Khonsari, Michael M [Baton Rouge, LA; Somanchi, Anoop K [Fremont, CA

2007-08-07

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

The effects of 595- and 1,064-nm lasers on rooster comb blood vessels using dual-wavelength and multipulse techniques.

PubMed

Li, Guang; Sun, Jianfang; Shao, Xuebao; Sang, Honggui; Zhou, Zhanchao

2011-10-01

After laser irradiation, hemoglobin can transform into methemoglobin and coagulum, which have high absorptivity of near-infrared light. Sequential irradiation with 595 nm and 1,064 nm may be more effective than single wavelength to decrease residual vessel number in rooster combs. Six protocols (single pulse with 595 nm, double pulse with 595 nm, single pulse with 1,064 nm, double pulse with 1,064 nm, sequential irradiation with 595 nm and 1,064 nm (multiplex), and a blank control group) were used to compare the effects of sequential and single-wavelength irradiation on reducing residual vessel number, as well as the epidermal side effects, in the rooster comb. Different treatment techniques were applied to the same comb, at the same time. The treated areas of the epidermis and the residual vessels were observed using an optical microscope. All five techniques were effective in decreasing the number of residual vessels in the comb, and the side effects on the epidermis were similar for all. Considering the selectivity of the 595-nm laser and the rich melanin in the human epidermis, the dual-wavelength laser has a distinct advantage in treating vascular lesions. The authors have indicated no significant interest with commercial supporters. © 2011 by the American Society for Dermatologic Surgery, Inc.

General Methods for Analysis of Sequential “n-step” Kinetic Mechanisms: Application to Single Turnover Kinetics of Helicase-Catalyzed DNA Unwinding

PubMed Central

Lucius, Aaron L.; Maluf, Nasib K.; Fischer, Christopher J.; Lohman, Timothy M.

2003-01-01

Helicase-catalyzed DNA unwinding is often studied using “all or none” assays that detect only the final product of fully unwound DNA. Even using these assays, quantitative analysis of DNA unwinding time courses for DNA duplexes of different lengths, L, using “n-step” sequential mechanisms, can reveal information about the number of intermediates in the unwinding reaction and the “kinetic step size”, m, defined as the average number of basepairs unwound between two successive rate limiting steps in the unwinding cycle. Simultaneous nonlinear least-squares analysis using “n-step” sequential mechanisms has previously been limited by an inability to float the number of “unwinding steps”, n, and m, in the fitting algorithm. Here we discuss the behavior of single turnover DNA unwinding time courses and describe novel methods for nonlinear least-squares analysis that overcome these problems. Analytic expressions for the time courses, fss(t), when obtainable, can be written using gamma and incomplete gamma functions. When analytic expressions are not obtainable, the numerical solution of the inverse Laplace transform can be used to obtain fss(t). Both methods allow n and m to be continuous fitting parameters. These approaches are generally applicable to enzymes that translocate along a lattice or require repetition of a series of steps before product formation. PMID:14507688

General methods for analysis of sequential "n-step" kinetic mechanisms: application to single turnover kinetics of helicase-catalyzed DNA unwinding.

PubMed

Lucius, Aaron L; Maluf, Nasib K; Fischer, Christopher J; Lohman, Timothy M

2003-10-01

Helicase-catalyzed DNA unwinding is often studied using "all or none" assays that detect only the final product of fully unwound DNA. Even using these assays, quantitative analysis of DNA unwinding time courses for DNA duplexes of different lengths, L, using "n-step" sequential mechanisms, can reveal information about the number of intermediates in the unwinding reaction and the "kinetic step size", m, defined as the average number of basepairs unwound between two successive rate limiting steps in the unwinding cycle. Simultaneous nonlinear least-squares analysis using "n-step" sequential mechanisms has previously been limited by an inability to float the number of "unwinding steps", n, and m, in the fitting algorithm. Here we discuss the behavior of single turnover DNA unwinding time courses and describe novel methods for nonlinear least-squares analysis that overcome these problems. Analytic expressions for the time courses, f(ss)(t), when obtainable, can be written using gamma and incomplete gamma functions. When analytic expressions are not obtainable, the numerical solution of the inverse Laplace transform can be used to obtain f(ss)(t). Both methods allow n and m to be continuous fitting parameters. These approaches are generally applicable to enzymes that translocate along a lattice or require repetition of a series of steps before product formation.

Development of Advanced Carbon Face Seals for Aircraft Engines

NASA Astrophysics Data System (ADS)

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.

Annular honeycomb seals: Test results for leakage and rotordynamic coefficients; comparisons to labyrinth and smooth configurations

NASA Technical Reports Server (NTRS)

Childs, Dara W.; Elrod, David; Hale, Keith

1989-01-01

Test results are presented for leakage and rotordynamic coefficients for seven honeycomb seals. All seals have the same radius, length, and clearance; however, the cell depths and diameters are varied. Rotordynamic data, which are presented, consist of the direct and cross-coupled stiffness coefficients and the direct damping coefficients. The rotordynamic-coefficient data show a considerable sensitivity to changes in cell dimensions; however, no clear trends are identifiable. Comparisons of test data for the honeycomb seals with labyrinth and smooth annular seals show the honeycomb seal had the best sealing (minimum leakage) performance, followed in order by the labyrinth and smooth seals. For prerotated fluid entering the seal, in the direction of shaft rotation, the honeycomb seal has the best rotordynamic stability followed in order by the labyrinth and smooth. For no prerotation, or fluid prerotation against shaft rotation, the labyrinth seal has the best rotordynamic stability followed in order by the smooth and honeycomb seals.

Resilient Flexible Pressure-Activated Seal

NASA Technical Reports Server (NTRS)

Steinetz, Bruce M. (Inventor); Dunlap, Patrick H., Jr. (Inventor)

2009-01-01

A resilient, flexible, pressure-activated, high-temperature seal is adapted to be interposed between high and low pressure regions to provide sealing between opposing surfaces of adjacent relatively movable structures. The seal comprises at least one C-shaped sheet element. The C-shaped element design enables the seal to be pressure-activated to provide a radially outward biasing force, responsive to a seal-activating pressure differential acting across the seal thereby increasing resiliency. A centrally-located, resilient core structure provides load bearing and insulating properties. In an exemplary embodiment where at least two seal elements are used, each layer has a cutout slot pattern and the remaining strip material pattern. The slots provide flexibility to the seal, enabling the seal to be manually contoured to seal around corners and curves. The strip material of each layer covers the slots in each adjacent layer to minimize leakage through the slots. Attached barrier strips can block interface leakage between the seal and the opposing surfaces.

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

NASA Astrophysics Data System (ADS)

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.

Airfoil seal system for gas turbine engine

DOEpatents

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.

Combat Ration Network for Technology Implementation (CORANET II) Knurled Seal Heat Bar

DTIC Science & Technology

2010-08-01

bench top comparison of ultrasonic sealing technology that included the participation of five ultrasonic sealing equipment manufacturers . Project...packaging journals • On-line web search yielded no useful research results • Contact with machine manufactures produced anecdotal evidence of improved...seal characteristics without documentation or research results • One manufacturer suggested rounded seal bars or seal rubbers for improved sealing

Acupuncture and PC6 stimulation for the prevention of postoperative nausea and vomiting in patients undergoing elective laparoscopic resection of colorectal cancer: a study protocol for a three-arm randomised pilot trial.

PubMed

Kim, Kun Hyung; Kim, Dae Hun; Bae, Ji Min; Son, Gyung Mo; Kim, Kyung Hee; Hong, Seung Pyo; Yang, Gi Young; Kim, Hee Young

2017-01-04

This study aims to assess the feasibility of acupuncture and a Pericardium 6 (PC6) wristband as an add-on intervention of antiemetic medication for the prevention of postoperative nausea and vomiting (PONV) in patients undergoing elective laparoscopic colorectal cancer resection. A total of 60 participants who are scheduled to undergo elective laparoscopic resection of colorectal cancer will be recruited. An enhanced recovery after surgery protocol using standardised antiemetic medication will be provided for all participants. Participants will be equally randomised into acupuncture plus PC6 wristband (Acupuncture), PC6 wristband alone (Wristband), or no acupuncture or wristband (Control) groups using computer-generated random numbers concealed in opaque, sealed, sequentially numbered envelopes. For the acupuncture combined with PC6 wristband group, the embedded auricular acupuncture technique for preoperative anxiolysis and up to three sessions of acupuncture treatments with manual and electrical stimulation within 48 hours after surgery will be provided by qualified Korean medicine doctors. The PC6 wristband will be applied in the Acupuncture and Wristband groups, beginning 1 hour before surgery and lasting 48 hours postoperatively. The primary outcome will be the number of participants who experience moderate or severe nausea, defined as nausea at least 4 out of 10 on a severity numeric rating scale or vomiting at 24 hours after surgery. Secondary outcomes, including symptom severity, participant global assessments and satisfaction, quality of life, physiological recovery, use of medication and length of hospital stay, will be assessed. Adverse events and postoperative complications will be measured for 1 month after surgery. All participants will provide written informed consent. The study has been approved by the institutional review board (IRB). This pilot trial will inform a full-scale randomised trial of acupuncture combined with PC6 stimulation for the prevention of PONV in patients undergoing elective laparoscopic colorectal cancer surgery. NCT02509143. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

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

NASA Astrophysics Data System (ADS)

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 bore over standard brush seal designs. Experimental results of the HFBS showed leakage reductions of 6 to 7 times that of a standard brush seal at the same operating pressure ratios and rotational speed and an order of magnitude less than numerical predictions of a standard labyrinth seal. (Abstract shortened by UMI.)

Brucella Antibodies in Alaskan True Seals and Eared Seals-Two Different Stories.

PubMed

Nymo, Ingebjørg H; Rødven, Rolf; Beckmen, Kimberlee; Larsen, Anett K; Tryland, Morten; Quakenbush, Lori; Godfroid, Jacques

2018-01-01

Brucella pinnipedialis was first isolated from true seals in 1994 and from eared seals in 2008. Although few pathological findings have been associated with infection in true seals, reproductive pathology including abortions, and the isolation of the zoonotic strain type 27 have been documented in eared seals. In this study, a Brucella enzyme-linked immunosorbent assay (ELISA) and the Rose Bengal test (RBT) were initially compared for 206 serum samples and a discrepancy between the tests was found. Following removal of lipids from the serum samples, ELISA results were unaltered while the agreement between the tests was improved, indicating that serum lipids affected the initial RBT outcome. For the remaining screening, we used ELISA to investigate the presence of Brucella antibodies in sera of 231 eared and 1,412 true seals from Alaskan waters sampled between 1975 and 2011. In eared seals, Brucella antibodies were found in two Steller sea lions ( Eumetopias jubatus ) (2%) and none of the 107 Northern fur seals ( Callorhinus ursinus ). The low seroprevalence in eared seals indicate a low level of exposure or lack of susceptibility to infection. Alternatively, mortality due to the Brucella infection may remove seropositive animals from the population. Brucella antibodies were detected in all true seal species investigated; harbor seals ( Phoca vitulina ) (25%), spotted seals ( Phoca largha ) (19%), ribbon seals ( Histriophoca fasciata ) (16%), and ringed seals ( Pusa hispida hispida ) (14%). There was a low seroprevalence among pups, a higher seroprevalence among juveniles, and a subsequent decreasing probability of seropositivity with age in harbor seals. Similar patterns were present for the other true seal species; however, solid conclusions could not be made due to sample size. This pattern is in accordance with previous reports on B. pinnipedialis infections in true seals and may suggest environmental exposure to B. pinnipedialis at the juvenile stage, with a following clearance of infection. Furthermore, analyses by region showed minor differences in the probability of being seropositive for harbor seals from different regions regardless of the local seal population trend, signifying that the Brucella infection may not cause significant mortality in these populations. In conclusion, the Brucella infection pattern is very different for eared and true seals.

Seal coat damage evaluation due to superheavy load moves based on a mechanistic-empirical approach.

DOT National Transportation Integrated Search

2010-03-01

The number of superheavy load (SHL) moves has increased drastically within the past 5 years in : Texas. Along with the increasing SHL moves, the Texas Department of Transportation (TxDOT) has : become increasingly aware of the rising concerns associa...

Discovery of a Novel Hepatovirus (Phopivirus of Seals) Related to Human Hepatitis A Virus.

PubMed

Anthony, S J; St Leger, J A; Liang, E; Hicks, A L; Sanchez-Leon, M D; Jain, K; Lefkowitch, J H; Navarrete-Macias, I; Knowles, N; Goldstein, T; Pugliares, K; Ip, H S; Rowles, T; Lipkin, W I

2015-08-25

Describing the viral diversity of wildlife can provide interesting and useful insights into the natural history of established human pathogens. In this study, we describe a previously unknown picornavirus in harbor seals (tentatively named phopivirus) that is related to human hepatitis A virus (HAV). We show that phopivirus shares several genetic and phenotypic characteristics with HAV, including phylogenetic relatedness across the genome, a specific and seemingly quiescent tropism for hepatocytes, structural conservation in a key functional region of the type III internal ribosomal entry site (IRES), and a codon usage bias consistent with that of HAV. Hepatitis A virus (HAV) is an important viral hepatitis in humans because of the substantial number of cases each year in regions with low socioeconomic status. The origin of HAV is unknown, and no nonprimate HAV-like viruses have been described. Here, we describe the discovery of an HAV-like virus in seals. This finding suggests that the diversity and evolutionary history of these viruses might be far greater than previously thought and may provide insight into the origin and pathogenicity of HAV. Copyright © 2015 Anthony et al.

Assessment of Performance of the Industrial Process of Bulk Vacuum Packaging of Raw Meat with Nondestructive Optical Oxygen Sensing Systems.

PubMed

Kelly, Caroline A; Cruz-Romero, Malco; Kerry, Joseph P; Papkovsky, Dmitri P

2018-05-02

The commercially-available optical oxygen-sensing system Optech-O₂ Platinum was applied to nondestructively assess the in situ performance of bulk, vacuum-packaged raw beef in three ~300 kg containers. Twenty sensors were attached to the inner surface of the standard bin-contained laminate bag (10 on the front and back sides), such that after filling with meat and sealing under vacuum, the sensors were accessible for optical interrogation with the external reader device. After filling and sealing each bag, the sensors were measured repetitively and nondestructively over a 15-day storage period at 1 °C, thus tracking residual oxygen distribution in the bag and changes during storage. The sensors revealed a number of unidentified meat quality and processing issues, and helped to improve the packaging process by pouring flakes of dry ice into the bag. Sensor utility in mapping the distribution of residual O₂ in sealed bulk containers and optimising and improving the packaging process, including handling and storage of bulk vacuum-packaged meat bins, was evident.

DEVELOPMENT OF A CERAMIC TAMPER INDICATING SEAL: SRNL CONTRIBUTIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krementz, D.; Brinkman, K.; Martinez-Rodriguez, M.

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 providemore » 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.« less

A study of leakage rates through mine seals in underground coal mines

PubMed Central

Schatzel, Steven J.; Krog, Robert B.; Mazzella, Andrew; Hollerich, Cynthia; Rubinstein, Elaine

2015-01-01

The National Institute for Occupational Safety and Health conducted a study on leakage rates through underground coal mine seals. Leakage rates of coal bed gas into active workings have not been well established. New seal construction standards have exacerbated the knowledge gap in our understanding of how well these seals isolate active workings near a seal line. At a western US underground coal mine, we determined seal leakage rates ranged from about 0 to 0.036 m3/s for seven 340 kPa seals. The seal leakage rate varied in essentially a linear manner with variations in head pressure at the mine seals. PMID:26322119

SEALING MEANS FOR RELATIVELY ROTATABLE MEMBERS

DOEpatents

Skarstrom, C.S.

1960-10-25

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

Gas Turbine Engine Carbon Oil Seals Computerized Assembly

NASA Technical Reports Server (NTRS)

Lee, Robert

2006-01-01

In a bearing compartment there are a series of parts when assembled determine the location of the bearing and seal as related to the centerline of rotation. We see part datums that do not establish A coincident path from the bearing to the seal. High engine vibration can cause severe oil leakage. The inability of the seal to respond fast enough to the rotating element Radial Seal: Sensitive to housing air pressure Sensitive to seal runout ? Axial Seal: Very sensitive to seal perpendicularity to shaft. Goals include: 1) Repeatable assembly process; 2) Accurate assembly process; 3) Minimize seal runout; 4) Design to engine centerline of rotation, i.e. bearings.

Multilayer compressive seal for sealing in high temperature devices

DOEpatents

Chou, Yeong-Shyung [Richland, WA; Stevenson, Jeffry W [Richland, WA

2007-08-21

A mica based compressive seal has been developed exhibiting superior thermal cycle stability when compared to other compressive seals known in the art. The seal is composed of compliant glass or metal interlayers and a sealing (gasket) member layer composed of mica that is infiltrated with a glass forming material, which effectively reduces leaks within the seal. The compressive seal shows approximately a 100-fold reduction in leak rates compared with previously developed hybrid seals after from 10 to about 40 thermal cycles under a compressive stress of from 50 psi to 100 psi at temperatures in the range from 600.degree. C. to about 850.degree. C.

Application study of magnetic fluid seal in hydraulic turbine

NASA Astrophysics Data System (ADS)

Yu, Z. Y.; Zhang, W.

2012-11-01

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.

The SSME seal test program: Leakage tests for helically-grooved seals

NASA Technical Reports Server (NTRS)

Childs, D. W.

1983-01-01

Helically grooved annular seal configurations were tested in highly turbulent flow to determine if reduced leakage and enhanced stability would result from the pumping action of the seal. It was found that: (1) leakage of a helically grooved seals decreases with running speed; (2) leakage reduction due to increased running speed is greater at lower values of R sub a; (3) an asymptote for leakage reduction is indicated with increasing running speed; (4) leakage is reduced by reducing the ridge (minimum) and average clearances; (5) leakage increases with increasing pitch angles and with increasing groove depth. Plain seals with smooth rotors and stators will leak more than a helically grooved seal. It was also found that plain seals with a rough rotor and a rough stator leak less than a properly designed helically grooved seal. A properly designed helically grooved seal consumes at least twice as much power as a conventional annular seal.

Investigations of Shuttle Main Landing Gear Door Environmental Seals

NASA Technical Reports Server (NTRS)

Finkbeiner, Joshua; Dunlap, Pat; Steinetz, Bruce; DeMango, Jeff; Newswander, Daniel

2005-01-01

The environmental seals for the main landing gear doors of the Shuttle Orbiters were raised by the Columbia Accident Investigation Board as a potential safety concern. Inspections of seals installed on the Shuttle Discovery revealed that they were permanently deformed and no longer met certified seal compression requirements. Replacement of the seals led to the inability to fully close the main landing gear doors. Johnson Space Center requested that Glenn Research Center conduct tests on the main landing gear door environmental seals to assist in installing the seals in a manner to allow the main landing gear doors to fully close. Further testing was conducted to fill out the seal performance database. Results from the testing indicated that the method of bonding the seals was important in reducing seal loads on the main landing gear doors. Also, the replacement seals installed in Shuttle Discovery were found to have leakage performance sufficient to meet the certification requirements.

Status of Understanding for Seal Materials

NASA Technical Reports Server (NTRS)

Brown, P. F.

1984-01-01

Material selection for mainshaft face and ring seals, labyrinth seals, accessory gearbox face seals, and lip seals are discussed in light of tribology requirements and a given seal application. Carbon graphite has been found to be one of the best sealing materials and it is widely used in current gas turbine mainshaft and accessory gearbox seals. Its popularity is due to its unique combination of properties which consists of dimensional stability, corrosion resistance, low friction, good self lubricating characteristics, high thermal conductivity and low thermal expansion, the latter two properties combining to provide good thermal shock resistance. A brief description of the seals and the requirements they must meet are discussed to provide insight into the limitations and advantages of the seals in containing the lubricant. A forecast is made of the operational requirements of main shaft and gearbox seals for advanced engines and candidate materials and coatings that may satisfy these advanced engine requirements.

Mechanical seal having a double-tier mating ring

DOEpatents

Khonsari, Michael M.; Somanchi, Anoop K.

2005-09-13

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

Emergency sacrificial sealing method in filters, equipment, or systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, Erik P.

A system seals a filter or equipment component to abase and will continue to seal the filter or equipment component to the base in the event of hot air or fire. The system includes a first sealing material between the filter or equipment component and the base; and a second sealing material between the filter or equipment component and the base and proximate the first sealing material. The first sealing material and the second seal material are positioned relative to each other and relative to the filter or equipment component and the base to seal the filter or equipment componentmore » to the base and upon the event of fire the second sealing material will be activated and expand to continue to seal the filter or equipment component to the base in the event of hot air or fire.« less

A dynamic analysis of rotary combustion engine seals

NASA Technical Reports Server (NTRS)

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.

Brush Seals for Improved Steam Turbine Performance

NASA Technical Reports Server (NTRS)

Turnquist, Norman; Chupp, Ray; Baily, Fred; Burnett, Mark; Rivas, Flor; Bowsher, Aaron; Crudgington, Peter

2006-01-01

GE Energy has retrofitted brush seals into more than 19 operating steam turbines. Brush seals offer superior leakage control compared to labyrinth seals, owing to their compliant nature and ability to maintain very tight clearances to the rotating shaft. Seal designs have been established for steam turbines ranging in size from 12 MW to over 1200 MW, including fossil, nuclear, combined-cycle and industrial applications. Steam turbines present unique design challenges that must be addressed to ensure that the potential performance benefits of brush seals are realized. Brush seals can have important effects on the overall turbine system that must be taken into account to assure reliable operation. Subscale rig tests are instrumental to understanding seal behavior under simulated steam-turbine operating conditions, prior to installing brush seals in the field. This presentation discusses the technical challenges of designing brush seals for steam turbines; subscale testing; performance benefits of brush seals; overall system effects; and field applications.

Regenerator seal design

DOEpatents

Eckart, Francis H.

1982-01-01

A rotary regenerator disc matrix has a face seal with a cross arm and arcuate rim segments joined by prestress clamps to prestrain the arcuate rim seals so as to compensate seal rim twisting or coning and resultant disc face seal leakage as produced by operating thermal gradients across the seal.

High-Speed, High-Temperature Finger Seal Test Evaluated

NASA Technical Reports Server (NTRS)

Proctor, Margaret P.

2003-01-01

A finger seal, designed and fabricated by Honeywell Engines, Systems and Services, was tested at the NASA Glenn Research Center at surface speeds up to 1200 ft/s, air temperatures up to 1200 F, and pressures across the seal of 75 psid. These are the first test results obtained with NASA s new High-Temperature, High-Speed Turbine Seal Test Rig (see the photograph). The finger seal is an innovative design recently patented by AlliedSignal Engines, which has demonstrated considerably lower leakage than commonly used labyrinth seals and is considerably cheaper than brush seals. The cost to produce finger seals is estimated to be about half of the cost to produce brush seals. Replacing labyrinth seals with fingers seals at locations that have high-pressure drops in gas turbine engines, typically main engine and thrust seals, can reduce air leakage at each location by 50 percent or more. This directly results in a 0.7- to 1.4-percent reduction in specific fuel consumption and a 0.35- to 0.7-percent reduction in direct operating costs . Because the finger seal is a contacting seal, this testing was conducted to address concerns about its heat generation and life capability at the higher speeds and temperatures required for advanced engines. The test results showed that the seal leakage and wear performance are acceptable for advanced engines.

50 CFR 218.230 - Specified activity, level of taking, and species.

Code of Federal Regulations, 2012 CFR

2012-10-01

...), northern elephant seal (Mirounga angustirostris), northern fur seal (Callorhinus ursinus), ribbon seal... seal (Arctocephalus australis), South American sea lion (Otaria flavescens), southern elephant seal...

50 CFR 218.230 - Specified activity, level of taking, and species.

Code of Federal Regulations, 2014 CFR

2014-10-01

...), northern elephant seal (Mirounga angustirostris), northern fur seal (Callorhinus ursinus), ribbon seal... seal (Arctocephalus australis), South American sea lion (Otaria flavescens), southern elephant seal...

50 CFR 218.230 - Specified activity, level of taking, and species.

Code of Federal Regulations, 2013 CFR

2013-10-01

...), northern elephant seal (Mirounga angustirostris), northern fur seal (Callorhinus ursinus), ribbon seal... seal (Arctocephalus australis), South American sea lion (Otaria flavescens), southern elephant seal...

Echoes from the past: Regional variations in recovery within a harbour seal population.

PubMed

Brasseur, Sophie M J M; Reijnders, Peter J H; Cremer, Jenny; Meesters, Erik; Kirkwood, Roger; Jensen, Lasse Fast; Jeβ, Armin; Galatius, Anders; Teilmann, Jonas; Aarts, Geert

2018-01-01

Terrestrial and marine wildlife populations have been severely reduced by hunting, fishing and habitat destruction, especially in the last centuries. Although management regulations have led to the recovery of some populations, the underlying processes are not always well understood. This study uses a 40-year time series of counts of harbour seals (Phoca vitulina) in the Wadden Sea to study these processes, and demonstrates the influence of historical regional differences in management regimes on the recovery of this population. While the Wadden Sea is considered one ecologically coupled zone, with a distinct harbour seal population, the area is divided into four geo-political regions i.e. the Netherlands, Lower Saxony including Hamburg, Schleswig-Holstein and Denmark. Gradually, seal hunting was banned between 1962 and 1977 in the different regions. Counts of moulting harbour seals and pup counts, obtained during aerial surveys between 1974 and 2014, show a population growth from approximately 4500 to 39,000 individuals. Population growth models were developed to assess if population growth differed between regions, taking into account two Phocine Distemper Virus (PDV) epizootics, in 1988 and 2002 which seriously affected the population. After a slow start prior to the first epizootic, the overall population grew exponentially at rates close to assumed maximum rates of increase in a harbour seal population. Recently, growth slowed down, potentially indicative of approaching carrying capacity. Regional differences in growth rates were demonstrated, with the highest recovery in Netherlands after the first PDV epizootic (i.e. 17.9%), suggesting that growth was fuelled by migration from the other regions, where growth remained at or below the intrinsic growth rate (13%). The seals' distribution changed, and although the proportion of seals counted in the German regions declined, they remained by far the most important pupping region, with approximately 70% of all pups being born there. It is hypothesised that differences in hunting regime, preceding the protection in the 1960's and 1970's, created unbalance in the distribution of breeding females throughout the Wadden Sea, which prevailed for decades. Breeding site fidelity promoted the growth in pup numbers at less affected breeding sites, while recolonisation of new breeding areas would be suppressed by the philopatry displayed by the animals born there. This study shows that for long-lived species, variable management regimes in this case hunting regulations, across a species' range can drive population dynamics for several generations.

30 CFR 57.8535 - Seals.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Seals. 57.8535 Section 57.8535 Mineral....8535 Seals. Seals shall be provided with a means for checking the quality of air behind the seal and a means to prevent a water head from developing unless the seal is designed to impound water. ...

30 CFR 57.8535 - Seals.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Seals. 57.8535 Section 57.8535 Mineral....8535 Seals. Seals shall be provided with a means for checking the quality of air behind the seal and a means to prevent a water head from developing unless the seal is designed to impound water. ...

Acoustic Seal

NASA Technical Reports Server (NTRS)

Steinetz, Bruce M. (Inventor)

2006-01-01

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

Acoustic seal

NASA Technical Reports Server (NTRS)

Steinetz, Bruce M. (Inventor)

2006-01-01

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

Numerical analysis on the action of centrifuge force in magnetic fluid rotating shaft seals

NASA Astrophysics Data System (ADS)

Zou, Jibin; Li, Xuehui; Lu, Yongping; Hu, Jianhui

2002-11-01

The magnetic fluid seal is suitable for high-speed rotating shaft seal applications. Centrifuge force will have evident influence on magnetic fluid rotating shaft seals. The seal capacity of the rotating shaft seal can be improved or increased by some measures. Through hydrodynamic analysis the moving status of the magnetic fluid is worked out. By numerical method, the magnetic field and the isobars in the magnetic fluid of a seal device are computed. Then the influence of the centrifuge force on the magnetic fluid seal is calculated quantitatively.

Method and apparatus for detecting flaws and defects in heat seals

NASA Technical Reports Server (NTRS)

Rai, Kula R. (Inventor); Lew, Thomas M. (Inventor); Sinclair, Robert B. (Inventor)

1993-01-01

Flaws and defects in heat seals formed between sheets of translucent film are identified by optically examining consecutive lateral sections of the seal along the seal length. Each lateral seal section is illuminated and an optical sensor array detects the intensity of light transmitted through the seal section for the purpose of detecting and locating edges in the heat seal. A line profile for each consecutive seal section is derived having an amplitude proportional to the change in light intensity across the seal section. Instances in the derived line profile where the amplitude is greater than a threshold level indicate the detection of a seal edge. The detected edges in each derived line profile are then compared to a preset profile edge standard to identify the existence of a flaw or defect.

Aspirating Seal Development: Analytical Modeling and Seal Test Rig

NASA Technical Reports Server (NTRS)

Bagepalli, Bharat

1996-01-01

This effort is to develop large diameter (22 - 36 inch) Aspirating Seals for application in aircraft engines. Stein Seal Co. will be fabricating the 36-inch seal(s) for testing. GE's task is to establish a thorough understanding of the operation of Aspirating Seals through analytical modeling and full-scale testing. The two primary objectives of this project are to develop the analytical models of the aspirating seal system, to upgrade using GE's funds, GE's 50-inch seal test rig for testing the Aspirating Seal (back-to-back with a corresponding brush seal), test the aspirating seal(s) for seal closure, tracking and maneuver transients (tilt) at operating pressures and temperatures, and validate the analytical model. The objective of the analytical model development is to evaluate the transient and steady-state dynamic performance characteristics of the seal designed by Stein. The transient dynamic model uses a multi-body system approach: the Stator, Seal face and the rotor are treated as individual bodies with relative degrees of freedom. Initially, the thirty-six springs are represented as a single one trying to keep open the aspirating face. Stops (Contact elements) are provided between the stator and the seal (to compensate the preload in the fully-open position) and between the rotor face and Seal face (to detect rub). The secondary seal is considered as part of the stator. The film's load, damping and stiffness characteristics as functions of pressure and clearance are evaluated using a separate (NASA) code GFACE. Initially, a laminar flow theory is used. Special two-dimensional interpolation routines are written to establish exact film load and damping values at each integration time step. Additionally, other user-routines are written to read-in actual pressure, rpm, stator-growth and rotor growth data and, later, to transfer these as appropriate loads/motions in the system-dynamic model. The transient dynamic model evaluates the various motions, clearances and forces as the seals are subjected to different aircraft maneuvers: Windmilling restart; start-ground idle; ground idle-takeoff; takeoff-burst chop, etc. Results of this model show that the seal closes appropriately and does not ram into the rotor for all of the conditions analyzed. The rig upgrade design for testing Aspirating Seals has been completed. Long lead-time items (forgings, etc.) have been ordered.

2000 NASA Seal/Secondary Air System Workshop. Volume 1

NASA Technical Reports Server (NTRS)

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

2001-01-01

The 2000 NASA Seal/Secondary Air System Workshop covered four main areas: (1) overviews of NASA-sponsored Ultra-Efficient Engine Technology (UEET) and Access to Space Programs, with emphasis on program goals and seal needs; (2) review of turbine engine seal issues from the perspective of end users such as United Airlines; (3) reviews of sealing concepts, test results, experimental facilities, and numerical predictions; and (4) reviews of material development programs relevant to advanced seals development. The NASA UEET overview illustrates for the reader the importance of advanced technologies, including seals, in meeting future engine system efficiency and emission goals. GE, Pratt & Whitney, and Honeywell presented advanced seal development work being performed within their organizations. The NASA-funded GE/Stein Seal team has successfully demonstrated a large (3-ft. diam) aspirating seal that can withstand all anticipated pressures, speeds, and rotor runouts anticipated for a GE90 L.P. turbine balance piston location. GE/Stein Seal are fabricating a full-scale seal to be tested in a GE-90 ground test engine in early 2002. Pratt & Whitney and Stein Seal are investigating carbon seals to accommodate large radial movements anticipated in future geared-fan gearbox locations. Honeywell presented a finger seal design being considered for a high-temperature static combustor location incorporating ceramic finger elements. Successful demonstration of the braided carbon rope thermal barriers to extreme temperatures (5500 F) for short durations provide a new form of very high temperature thermal barrier for future Shuttle solid rocket motor nozzle joints. The X-37, X-38, and future highly reusable launch vehicles pose challenging control surface seal demands that require new seal concepts made from emerging high temperature ceramics and other materials.

An in vitro evaluation of the apical sealing ability of new polymeric endodontic filling systems.

PubMed

Onay, Emel Olga; Ungor, Mete; Unver, Saadet; Ari, Hale; Belli, Sema

2009-08-01

The objective of this study was to compare the short-term sealing abilities of recently introduced polymeric endodontic filling systems. Root canals of 120 extracted and decoronated human single-rooted teeth were instrumented using crown-down technique with HERO Shaper rotary instruments. The roots were divided randomly into 8 groups (6 experimental and 2 control groups of 15 roots each) and filled with different combinations of core and sealer as follows: group 1, RealSeal/Resilon; group 2, RealSeal/Herofill; group 3, Hybrid Root Seal/Resilon; group 4, Hybrid Root Seal/Herofill; group 5, MM-Seal/Resilon; group 6, MM-Seal/Herofill; group 7, positive controls (Herofill only); group 8, negative controls. Apical leakage quantity was evaluated after 1 week by using a fluid filtration model. For each sample, measurements of fluid movement were recorded at 2-minute intervals for a total of 8 minutes, and then averaged. The data were calculated and analyzed using the Kolmogorov-Smirnov test, 1-way analysis of variance (ANOVA), and the Tukey test. Significance was set at P less than .05. Multiple paired comparisons (Tukey test) showed that, of all the groups, MM-Seal/Herofill combination exhibited the least microleakage, and RealSeal/Herofill combination ranked second in this regard. The mean leakage values for the RealSeal/Resilon and MM-Seal/Resilon combinations were both significantly higher than the means for the other 4 experimental groups (P < .01). Hybrid Root Seal combined with Resilon resulted in significantly less microleakage than Hybrid Root Seal combined with Herofill (P = .001). The results suggest that the sealing properties of epoxy-resin-based sealer (MM-Seal) combined with gutta-percha (Herofill) are superior to those of methacrylate-based sealers (Hybrid Root Seal and Realseal) combined with Resilon.

Modular Organization of Exploratory Force Development Under Isometric Conditions in the Human Arm.

PubMed

Roh, Jinsook; Lee, Sang Wook; Wilger, Kevin D

2018-01-31

Muscle coordination of isometric force production can be explained by a smaller number of modules. Variability in force output, however, is higher during exploratory/transient force development phases than force maintenance phase, and it is not clear whether the same modular structure underlies both phases. In this study, eight neurologically-intact adults isometrically performed target force matches in 54 directions at hands, and electromyographic (EMG) data from eight muscles were parsed into four sequential phases. Despite the varying degree of motor complexity across phases (significant between-phase differences in EMG-force correlation, angular errors, and between-force correlations), the number/composition of motor modules were found equivalent across phases, suggesting that the CNS systematically modulated activation of the same set of motor modules throughout sequential force development.

A magnetic fluid seal for rotary blood pumps: image and computational analyses of behaviors of magnetic fluids.

PubMed

Mitamura, Yoshinori; Yano, Tetsuya; Okamoto, Eiji

2013-01-01

A magnetic fluid (MF) seal has excellent durability. The performance of an MF seal, however, has been reported to decrease in liquids (several days). We have developed an MF seal that has a shield mechanism. The seal was perfect for 275 days in water. To investigate the effect of a shield, behaviors of MFs in a seal in water were studied both experimentally and computationally. (a) Two kinds of MF seals, one with a shield and one without a shield, were installed in a centrifugal pump. Behaviors of MFs in the seals in water were observed with a video camera and high-speed microscope. In the seal without a shield, the surface of the water in the seal waved and the turbulent flow affected behaviors of the MFs. In contrast, MFs rotated stably in the seal with a shield in water even at high rotational speeds. (b) Computational fluid dynamics analysis revealed that a stationary secondary flow pattern in the seal and small velocity difference between magnetic fluid and water at the interface. These MF behaviors prolonged the life of an MF seal in water.

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

NASA Technical Reports Server (NTRS)

Murray, Harry E.; Erwin, Mary A.

1945-01-01

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

Seal Investigations of an Active Clearance Control System Concept

NASA Technical Reports Server (NTRS)

Steinetz, Bruce M.; Taylor, Shawn; Oswald, Jay; DeCastro, Jonathan A.

2006-01-01

In an effort to improve upon current thermal active clearance control methods, a first generation, fast-acting mechanically actuated, active clearance control system has been designed and installed into a non-rotating test rig. In order to harvest the benefit of tighter blade tip clearances, low-leakage seals are required for the actuated carrier segments of the seal shroud to prevent excessive leakage of compressor discharge (P3) cooling air. The test rig was designed and fabricated to facilitate the evaluation of these types of seals, identify seal leakage sources, and test other active clearance control system concepts. The objective of this paper is to present both experimental and analytical investigations into the nature of the face-seal to seal-carrier interface. Finite element analyses were used to examine face seal contact pressures and edge-loading under multiple loading conditions, varied E-seal positions and two new face seal heights. The analyses indicated that moving the E-seal inward radially and reducing face seal height would lead to more uniform contact conditions between the face seal and the carriers. Lab testing confirmed that moving the balance diameter inward radially caused a decrease in overall system leakage.

Hydrodynamically Lubricated Rotary Shaft Having Twist Resistant Geometry

DOEpatents

Dietle, Lannie; Gobeli, Jeffrey D.

1993-07-27

A hydrodynamically lubricated squeeze packing type rotary shaft with a cross-sectional geometry suitable for pressurized lubricant retention is provided which, in the preferred embodiment, incorporates a protuberant static sealing interface that, compared to prior art, dramatically improves the exclusionary action of the dynamic sealing interface in low pressure and unpressurized applications by achieving symmetrical deformation of the seal at the static and dynamic sealing interfaces. In abrasive environments, the improved exclusionary action results in a dramatic reduction of seal and shaft wear, compared to prior art, and provides a significant increase in seal life. The invention also increases seal life by making higher levels of initial compression possible, compared to prior art, without compromising hydrodynamic lubrication; this added compression makes the seal more tolerant of compression set, abrasive wear, mechanical misalignment, dynamic runout, and manufacturing tolerances, and also makes hydrodynamic seals with smaller cross-sections more practical. In alternate embodiments, the benefits enumerated above are achieved by cooperative configurations of the seal and the gland which achieve symmetrical deformation of the seal at the static and dynamic sealing interfaces. The seal may also be configured such that predetermined radial compression deforms it to a desired operative configuration, even through symmetrical deformation is lacking.

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

PubMed

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 (< 0.5 cc/day). An ultrafiltration unit integrated in the recirculating purge system continuously purifies and sterilizes the purge fluid for more than 5 months without filter change. The 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.

An Update on Structural Seal Development at NASA GRC

NASA Technical Reports Server (NTRS)

Dunlap, Pat; Steinetz, Bruce; Finkbeiner, Josh; DeMange, Jeff; Taylor, Shawn; Daniels, Chris; Oswald, Jay

2006-01-01

A viewgraph presentation describing advanced structural seal development for NASA exploration is shown. The topics include: 1) GRC Structural Seals Team Research Areas; 2) Research Areas & Objective; 3) Wafer Seal Geometry/Flow Investigations; 4) Wafer Seal Installation DOE Study; 5) Results of Wafer Seal Installation DOE Study; 6) Wafer Geometry Study: Thickness Variations; 7) Wafer Geometry Study: Full-Size vs. Half-Size Wafers; 8) Spring Tube Seal Development; 9) Resiliency Improvement for Rene 41 Spring Tube; 10) Spring Tube Seals: Go-Forward Plan; 11) High Temperature Seal Preloader Development: TZM Canted Coil Spring; 12) TZM Canted Coil Spring Development; 13) Arc Jet Test Rig Development; and 14) Arc Jet Test Rig Status.

Hydrodynamic trapping for rapid assembly and in situ electrical characterization of droplet interface bilayer arrays

DOE PAGES

Nguyen, Mary -Anne; Srijanto, Bernadeta; Collier, C. Patrick; ...

2016-08-02

The droplet interface bilayer (DIB) is a modular technique for assembling planar lipid membranes between water droplets in oil. The DIB method thus provides a unique capability for developing digital, droplet-based membrane platforms for rapid membrane characterization, drug screening and ion channel recordings. This paper demonstrates a new, low-volume microfluidic system that automates droplet generation, sorting, and sequential trapping in designated locations to enable the rapid assembly of arrays of DIBs. The channel layout of the device is guided by an equivalent circuit model, which predicts that a serial arrangement of hydrodynamic DIB traps enables sequential droplet placement and minimizesmore » the hydrodynamic pressure developed across filled traps to prevent squeeze-through of trapped droplets. Furthermore, the incorporation of thin-film electrodes fabricated via evaporation metal deposition onto the glass substrate beneath the channels allows for the first time in situ, simultaneous electrical interrogation of multiple DIBs within a sealed device. Combining electrical measurements with imaging enables measurements of membrane capacitance and resistance and bilayer area, and our data show that DIBs formed in different trap locations within the device exhibit similar sizes and transport properties. Simultaneous, single channel recordings of ion channel gating in multiple membranes are obtained when alamethicin peptides are incorporated into the captured droplets, qualifying the thin-film electrodes as a means for measuring stimuli-responsive functions of membrane-bound biomolecules. Furthermore, this novel microfluidic-electrophysiology platform provides a reproducible, high throughput method for performing electrical measurements to study transmembrane proteins and biomembranes in low-volume, droplet-based membranes.« less

Hydrodynamic trapping for rapid assembly and in situ electrical characterization of droplet interface bilayer arrays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nguyen, Mary -Anne; Srijanto, Bernadeta; Collier, C. Patrick

The droplet interface bilayer (DIB) is a modular technique for assembling planar lipid membranes between water droplets in oil. The DIB method thus provides a unique capability for developing digital, droplet-based membrane platforms for rapid membrane characterization, drug screening and ion channel recordings. This paper demonstrates a new, low-volume microfluidic system that automates droplet generation, sorting, and sequential trapping in designated locations to enable the rapid assembly of arrays of DIBs. The channel layout of the device is guided by an equivalent circuit model, which predicts that a serial arrangement of hydrodynamic DIB traps enables sequential droplet placement and minimizesmore » the hydrodynamic pressure developed across filled traps to prevent squeeze-through of trapped droplets. Furthermore, the incorporation of thin-film electrodes fabricated via evaporation metal deposition onto the glass substrate beneath the channels allows for the first time in situ, simultaneous electrical interrogation of multiple DIBs within a sealed device. Combining electrical measurements with imaging enables measurements of membrane capacitance and resistance and bilayer area, and our data show that DIBs formed in different trap locations within the device exhibit similar sizes and transport properties. Simultaneous, single channel recordings of ion channel gating in multiple membranes are obtained when alamethicin peptides are incorporated into the captured droplets, qualifying the thin-film electrodes as a means for measuring stimuli-responsive functions of membrane-bound biomolecules. Furthermore, this novel microfluidic-electrophysiology platform provides a reproducible, high throughput method for performing electrical measurements to study transmembrane proteins and biomembranes in low-volume, droplet-based membranes.« less

Seeds in space experiment. [long duration exposure facility

NASA Technical Reports Server (NTRS)

Alston, Jim A.

1992-01-01

Two million seeds of 120 different varieties representing 106 species, 97 genera, and 55 plant families were flown aboard the Long Duration Exposure Facility (LDEF). The seeds were housed in one sealed canister and in two small vented canisters. After being returned to earth, the seeds were germinated and the germination rates and development of the resulting plants were compared to the performance of the control seeds that stayed in the Park Seed's seed storage facility. There was a better survival rate in the sealed canister in space than at the storage facility at Park Seed. At least some of the seeds in each of the vented canisters survived the exposure to vacuum for almost six years. The number of observed apparent mutations was very low.

Investigations of Shuttle Main Landing Gear Door Environmental Seals

NASA Technical Reports Server (NTRS)

Finkbeiner, Joshua; DeMange, Jeff; Dunlap, Pat; Steinetz, Bruce; Newswander, Daniel

2006-01-01

The Columbia Accident investigation Board (CAIB) requested an investigation into the MLG door seals. Initially, the MLG door seals were thought to have been a potential contributor to the loss of Columbia. These suspicions were later found to be untrue, but the seals remained as a cause for concern in future flights. MLG door seals comprised of thermal barrier and environmental seal. This study focuses on the environmental seal for the MLG door.

36 CFR 1200.4 - How does NARA use its official seals?

Code of Federal Regulations, 2010 CFR

2010-07-01

... official seals? 1200.4 Section 1200.4 Parks, Forests, and Public Property NATIONAL ARCHIVES AND RECORDS ADMINISTRATION GENERAL RULES OFFICIAL SEALS How are NARA's Official Seals and Logos Designed and Used? § 1200.4 How does NARA use its official seals? NARA uses its three official seals to authenticate various...

36 CFR 1200.4 - How does NARA use its official seals?

Code of Federal Regulations, 2011 CFR

2011-07-01

... official seals? 1200.4 Section 1200.4 Parks, Forests, and Public Property NATIONAL ARCHIVES AND RECORDS ADMINISTRATION GENERAL RULES OFFICIAL SEALS How are NARA's Official Seals and Logos Designed and Used? § 1200.4 How does NARA use its official seals? NARA uses its three official seals to authenticate various...

75 FR 58365 - Taking and Importing Marine Mammals; Taking Marine Mammals Incidental to Missile Launch...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-24

... governing the taking of Northern elephant seals (Mirounga angustirostris), Pacific harbor seals (Phoca... during missile launches at SNI. Northern elephant seals, Pacific harbor seals, and California sea lions... incidentally taken by Level B harassment annually: 474 Northern elephant seals; 467 Pacific harbor seals; and 1...

Effect of CrO3 Sealing Time on Anodized A12024-T3

NASA Astrophysics Data System (ADS)

Korda, Akhmad A.; Hidayat, R. Z.

2016-08-01

The effect of CrO3 sealing time on anodized aluminum alloy has been investigated. A1 2024-T3 were used as substrate. Anodizing was carried out using chromic acid. CrO3 sealing was conducted in CrO3 solution for 30, 60, 90, 120 and 150 minutes. As comparison, other specimens were also prepared as anodized and boiled water sealing. Thickness of the coating was observed by optical microscope. Anodized and sealing layer was analyzed by X- ray diffraction. The hardness of as anodized, boiled water sealing and CrO3 sealing were compared. The highest hardness is achieved by CrO3 sealed specimen and followed by boiled water sealing and as anodized specimens. The longer the processes of CrO3 sealing the higher layer thickness and therefore the higher hardness of the oxide layer. The best resistance to electrolyte penetration is achieved by the CrO3 sealed specimen followed by boiled water sealed and as anodized specimens. The higher thickness of oxide layer, the higher the resistance against electrolyte penetration.

Rotary kiln seal

DOEpatents

Drexler, Robert L.

1992-01-01

A rotary seal used to prevent the escape of contaminates from a rotating kiln incinerator. The rotating seal combines a rotating disc plate which is attached to the rotating kiln shell and four sets of non-rotating carbon seal bars housed in a primary and secondary housing and which rub on the sides of the disc. A seal air system is used to create a positive pressure in a chamber between the primary and secondary seals to create a positive air flow into the contaminated gas chamber. The seal air system also employs an air inlet located between the secondary and tertiary seals to further insure that no contaminates pass the seal and enter the external environment and to provide makeup air for the air which flows into the contaminated gas chamber. The pressure exerted by the seal bars on the rotating disc is controlled by means of a preload spring. The seal is capable of operating in a thermally changing environment where the both radial expansion and axial movement of the rotating kiln do not result in the failure of the seal.

Double angle seal forming lubricant film

DOEpatents

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.

Seal assembly

DOEpatents

Johnson, Roger Neal; Longfritz, William David

2001-01-01

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

Development of a new seal for use on large openings of pressurized spacecraft

NASA Technical Reports Server (NTRS)

Weddendorf, B.

1994-01-01

The goal of this project was to design, build, and test an example of the seal invented by the author for use on Space Station Freedom and patented in 1991. The seal features a metallic spring core and replaceable elastomeric sealing elements. The metallic spring is designed to retain the sealing force of the elastomeric element against both sides of face seal gland for any specified amount of waviness or separation of the glands. A seal able to tolerate at least 1.3 mm (0.05 in) of flange distortion or separation and a test fixture of this seal which allowed direct comparison testing of O-rings were built. These designs were tested to compare leakage at different amounts of flange deflection. Results of the testing show the development seal exceeded its requirement to seal 1.3 mm of flange separation by 1 mm. This compared with the O-ring leakage, increasing dramatically at 0.5 mm of separation. The development seal also leaked at a lower rate than the O-ring seals in all tests.

Feature Selection based on Machine Learning in MRIs for Hippocampal Segmentation

NASA Astrophysics Data System (ADS)

Tangaro, Sabina; Amoroso, Nicola; Brescia, Massimo; Cavuoti, Stefano; Chincarini, Andrea; Errico, Rosangela; Paolo, Inglese; Longo, Giuseppe; Maglietta, Rosalia; Tateo, Andrea; Riccio, Giuseppe; Bellotti, Roberto

2015-01-01

Neurodegenerative diseases are frequently associated with structural changes in the brain. Magnetic resonance imaging (MRI) scans can show these variations and therefore can be used as a supportive feature for a number of neurodegenerative diseases. The hippocampus has been known to be a biomarker for Alzheimer disease and other neurological and psychiatric diseases. However, it requires accurate, robust, and reproducible delineation of hippocampal structures. Fully automatic methods are usually the voxel based approach; for each voxel a number of local features were calculated. In this paper, we compared four different techniques for feature selection from a set of 315 features extracted for each voxel: (i) filter method based on the Kolmogorov-Smirnov test; two wrapper methods, respectively, (ii) sequential forward selection and (iii) sequential backward elimination; and (iv) embedded method based on the Random Forest Classifier on a set of 10 T1-weighted brain MRIs and tested on an independent set of 25 subjects. The resulting segmentations were compared with manual reference labelling. By using only 23 feature for each voxel (sequential backward elimination) we obtained comparable state-of-the-art performances with respect to the standard tool FreeSurfer.

Seals and Sealing Techniques

NASA Technical Reports Server (NTRS)

1972-01-01

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

Solid oxide fuel cell having a glass composite seal

DOEpatents

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.

Advanced helium purge seals for Liquid Oxygen (LOX) turbopumps

NASA Technical Reports Server (NTRS)

Shapiro, Wilbur; Lee, Chester C.

1989-01-01

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

Nuclear reactor sealing system

DOEpatents

McEdwards, James A.

1983-01-01

A liquid metal-cooled nuclear reactor sealing system. 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.

49 CFR 511.35 - Testimony upon oral examination.

Code of Federal Regulations, 2010 CFR

2010-10-01

... sealed envelope on the party conducting the examination. That party shall transmit the envelope to the... envelope endorsed with the title and docket number of the action and marked “Testimony of [name of witness... the examination shall pay for the transcription. (g) Failure to attend or to serve subpoena; expenses...

Index to Benet Weapons Laboratory (LCWSL) Technical Reports - 1979

DTIC Science & Technology

1980-09-01

Breech Machanisms Breech Seals Breeches, Cannon Cadmium Sulfide Calibration Cannon Auto Loader Cannon Tube Chemical Vapor Deposition REPORT NUMBER...PAGE(Trh«n Data SntaracQ (Con1t from block #20) Three basic specimen geometries were studied: 1. A symetric specimen; 2. A specimen with +5% wall

76 FR 46724 - Takes of Marine Mammals Incidental to Specified Activities; Seabird and Pinniped Research...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-03

... Nuevo Island, and Point Reyes National Seashore in central California (CA) for one year. PRBO, along... research activities for one year. NMFS reviewed PRBO's application and identified a number of issues...; observing seabird nesting habitat; restoring nesting burrows; observing breeding elephant seals, and...

Spring Flowers: Harvest of a Sensitive Eye

ERIC Educational Resources Information Center

Clark, Eloise; Levin, Ted

1978-01-01

Defining and describing a number of spring flowers, this article includes illustrations and explanations that demonstrate "art and science are born of the same parents". The flowers discussed are skunk cabbage, bellwort, spring beauty, jack-in-the-pulpit, Solomon's seal, wild geranium, showy orchids, moccasin flower, bluets, apple, and Indian…

Composite Materials for Maxillofacial Prostheses.

DTIC Science & Technology

1981-08-01

necessary and Identify byv block number) MAXILLOFACIAL PROSTHESES; PROSTHETIC MATERIALS: MICROCAPSULES : SOFT FILLERS; ELASTOMER COMPOSITES 2,. ABSTRACT...used as fillers in the fabrication of maxillofacial prostheses. The projected systems are elastomeric-shelled, liquid-filled microcapsules . Improvements...elastomeric-shelled, liquid-filled microcapsules . Experiments continued on the interfacial polymerization process, with spherical, sealed, capsules

78 FR 40057 - Airworthiness Directives; Airbus Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-03

... A321 series airplanes. This proposed AD was prompted by reports of certain sliding windows that were... numbers of sliding windows and sliding window seals, and modification if necessary. This proposed AD also... could lead to the functional loss of the sliding window as an exit, possibly preventing the flightcrew...

Feasibility Assessment of Thermal Barrier Seals for Extreme Transient Temperatures

NASA Technical Reports Server (NTRS)

Steinetz, Bruce M.; Dunlap, Patrick H., Jr.

1998-01-01

The assembly joints of modem solid rocket motor cases are generally sealed using conventional O-ring type seals. The 5500+ F combustion gases produced by rocket motors are kept a safe distance away from the seals by thick layers of phenolic insulation. Special compounds are used to fill insulation gaps leading up to the seals to prevent a direct flowpath to them. Design criteria require that the seals should not experience torching or charring during operation, or their sealing ability would be compromised. On limited occasions, NASA has observed charring of the primary O-rings of the Space Shuttle solid rocket nozzle assembly joints due to parasitic leakage paths opening up in the gap-fill compounds during rocket operation. NASA is investigating different approaches for preventing torching or charring of the primary O-rings. One approach is to implement a braided rope seal upstream of the primary O-ring to serve as a thermal barrier that prevents the hot gases from impinging on the O-ring seals. This paper presents flow, resiliency, and thermal resistance for several types of NASA rope seals braided out of carbon fibers. Burn tests were performed to determine the time to burn through each of the seals when exposed to the flame of an oxyacetylene torch (5500 F), representative of the 5500 F solid rocket motor combustion temperatures. Rope seals braided out of carbon fibers endured the flame for over six minutes, three times longer than solid rocket motor burn time. Room and high temperature flow tests are presented for the carbon seals for different amounts of linear compression. Room temperature compression tests were performed to assess seal resiliency and unit preloads as a function of compression. The thermal barrier seal was tested in a subscale "char" motor test in which the seal sealed an intentional defect in the gap insulation. Temperature measurements indicated that the seal blocked 2500 F combustion gases on the upstream side with very little temperature rise on the downstream side.

Transactivation potencies of the Baikal seal (Pusa sibirica) peroxisome proliferator-activated receptor α by perfluoroalkyl carboxylates and sulfonates: estimation of PFOA induction equivalency factors.

PubMed

Ishibashi, Hiroshi; Kim, Eun-Young; Iwata, Hisato

2011-04-01

The present study assessed the transactivation potencies of the Baikal seal (Pusa sibirica) peroxisome proliferator-activated receptor α (BS PPARα) by perfluorochemicals (PFCs) having various carbon chain lengths (C4-C12) using an in vitro reporter gene assay. Among the twelve PFCs treated with a range of 7.8-250 μM concentration, eight perfluoroalkyl carboxylates (PFCAs) and two perfluoroalkyl sulfonates (PFSAs) induced BS PPARα-mediated transcriptional activities in a dose-dependent manner. To compare the BS PPARα transactivation potencies of PFCs, the present study estimated the PFOA induction equivalency factors (IEFs), a ratio of the 50% effective concentration of PFOA to the concentration of each compound that can induce the response corresponding to 50% of the maximal response of PFOA. The order of IEFs for the PFCs was as follows: PFOA (IEF: 1)>PFHpA (0.89)>PFNA (0.61)>PFPeA (0.50)>PFHxS (0.41)>PFHxA (0.38)≈PFDA (0.37)>PFBA (0.26)=PFOS (0.26)>PFUnDA (0.15)≫PFDoDA and PFBuS (not activated). The structure-activity relationship analysis showed that PFCAs having more than seven perfluorinated carbons had a negative correlation (r=-1.0, p=0.017) between the number of perfluorinated carbons and the IEF of PFCAs, indicating that the number of perfluorinated carbon of PFCAs is one of the factors determining the transactivation potencies of the BS PPARα. The analysis also indicated that PFCAs were more potent than PFSAs with the same number of perfluorinated carbons. Treatment with a mixture of ten PFCs showed an additive action on the BS PPARα activation. Using IEFs of individual PFCs and hepatic concentrations of PFCs in the liver of wild Baikal seals, the PFOA induction equivalents (IEQs, 5.3-58 ng IEQ/g wet weight) were calculated. The correlation analysis revealed that the hepatic total IEQs showed a significant positive correlation with the hepatic expression levels of cytochrome P450 4A-like protein (r=0.53, p=0.036). This suggests that our approach may be useful for assessing the potential PPARα-mediated biological effects of complex mixtures of PFCs in wild Baikal seal population.

Self-acting shaft seals

NASA Technical Reports Server (NTRS)

Ludwig, L. P.

1978-01-01

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

Ultra high vacuum seal arrangement

DOEpatents

Flaherty, Robert

1981-01-01

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

Seal system with integral detector

DOEpatents

Fiarman, S.

1982-08-12

A seal system is disclosed for materials where security is of the essence, such as nuclear materials. The seal is tamper-indicating, indicates changes in environmental conditions that evidence attempts to bypass the seal, is unique and cost effective. The seal system is comprised of a seal where an optical signal is transmitted through a loop, with a detector to read said signal, and one or more additional detectors designed to detect environmental changes, these detectors being operatively associated with the seal so that detection of a break in the optical signal or detection of environmental changes will cause an observable change in the seal.

Leakage and Power Loss Test Results for Competing Turbine Engine Seals

NASA Technical Reports Server (NTRS)

Proctor, Margaret P.; Delgado, Irebert R.

2004-01-01

Advanced brush and finger seal technologies offer reduced leakage rates over conventional labyrinth seals used in gas turbine engines. To address engine manufacturers concerns about the heat generation and power loss from these contacting seals, brush, finger, and labyrinth seals were tested in the NASA High Speed, High Temperature Turbine Seal Test Rig. Leakage and power loss test results are compared for these competing seals for operating conditions up to 922 K (1200 F) inlet air temperature, 517 KPa (75 psid) across the seal, and surface velocities up to 366 m/s (1200 ft/s).

Design of Arithmetic Circuits for Complex Binary Number System

NASA Astrophysics Data System (ADS)

Jamil, Tariq

2011-08-01

Complex numbers play important role in various engineering applications. To represent these numbers efficiently for storage and manipulation, a (-1+j)-base complex binary number system (CBNS) has been proposed in the literature. In this paper, designs of nibble-size arithmetic circuits (adder, subtractor, multiplier, divider) have been presented. These circuits can be incorporated within von Neumann and associative dataflow processors to achieve higher performance in both sequential and parallel computing paradigms.

Sequential quantum cloning under real-life conditions

NASA Astrophysics Data System (ADS)

Saberi, Hamed; Mardoukhi, Yousof

2012-05-01

We consider a sequential implementation of the optimal quantum cloning machine of Gisin and Massar and propose optimization protocols for experimental realization of such a quantum cloner subject to the real-life restrictions. We demonstrate how exploiting the matrix-product state (MPS) formalism and the ensuing variational optimization techniques reveals the intriguing algebraic structure of the Gisin-Massar output of the cloning procedure and brings about significant improvements to the optimality of the sequential cloning prescription of Delgado [Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.98.150502 98, 150502 (2007)]. Our numerical results show that the orthodox paradigm of optimal quantum cloning can in practice be realized in a much more economical manner by utilizing a considerably lesser amount of informational and numerical resources than hitherto estimated. Instead of the previously predicted linear scaling of the required ancilla dimension D with the number of qubits n, our recipe allows a realization of such a sequential cloning setup with an experimentally manageable ancilla of dimension at most D=3 up to n=15 qubits. We also address satisfactorily the possibility of providing an optimal range of sequential ancilla-qubit interactions for optimal cloning of arbitrary states under realistic experimental circumstances when only a restricted class of such bipartite interactions can be engineered in practice.

Performance Evaluations of Ceramic Wafer Seals

NASA Technical Reports Server (NTRS)

Dunlap, Patrick H., Jr.; DeMange, Jeffrey J.; Steinetz, Bruce M.

2006-01-01

Future hypersonic vehicles will require high temperature, dynamic seals in advanced ramjet/scramjet engines and on the vehicle airframe to seal the perimeters of movable panels, flaps, and doors. Seal temperatures in these locations can exceed 2000 F, especially when the seals are in contact with hot ceramic matrix composite sealing surfaces. NASA Glenn Research Center is developing advanced ceramic wafer seals to meet the needs of these applications. High temperature scrub tests performed between silicon nitride wafers and carbon-silicon carbide rub surfaces revealed high friction forces and evidence of material transfer from the rub surfaces to the wafer seals. Stickage between adjacent wafers was also observed after testing. Several design changes to the wafer seals were evaluated as possible solutions to these concerns. Wafers with recessed sides were evaluated as a potential means of reducing friction between adjacent wafers. Alternative wafer materials are also being considered as a means of reducing friction between the seals and their sealing surfaces and because the baseline silicon nitride wafer material (AS800) is no longer commercially available.

2007 NASA Seal/Secondary Air System Workshop. Volume 1

NASA Technical Reports Server (NTRS)

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.

2008 NASA Seal/Secondary Air System Workshop

NASA Technical Reports Server (NTRS)

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

2009-01-01

The 2008 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.

Investigation of low cost, high reliability sealing techniques for hybrid microcircuits, phase 1

NASA Technical Reports Server (NTRS)

Perkins, K. L.; Licari, J. J.

1976-01-01

A preliminary investigation was made to determine the feasibility of using adhesive package sealing for hybrid microcircuits. Major effort consisted of: (1) surveying representative hybrid manufacturers to assess the current use of adhesives for package sealing; (2) making a cost comparison of metallurgical versus adhesive package sealing; (3) determining the seal integrity of gold plated flatpack type packages sealed with selected adhesives, thermal shock, temperature cycling, mechanical shock, and constant acceleration test environments; and (4) defining a more comprehensive study to continue the evaluation of adhesives for package sealing. Results showed that 1.27 cm square gold plated flatpack type packages sealed with the film adhesives and the paste adhesive retained their seal integrity after all tests, and that similarly prepared 2.54 cm square packages retained their seal integrity after all tests except the 10,000 g's constant acceleration test. It is concluded that these results are encouraging, but by no means sufficient to establish the suitability of adhesives for sealing high reliability hybrid microcircuits.

Performance of Subscale Docking Seals Under Simulated Temperature Conditions

NASA Technical Reports Server (NTRS)

Smith, Ian M.; Daniels, Christopher C.

2008-01-01

A universal docking system is being developed by the National Aeronautics and Space Administration (NASA) to support future space exploration missions to low Earth orbit (LEO), to the moon, and to Mars. The candidate docking seals for the system are a composite design consisting of elastomer seal bulbs molded into the front and rear sides of a metal ring. The test specimens were subscale seals with two different elastomer cross-sections and a 12-in. outside diameter. The seal assemblies were mated in elastomer seal-on-metal plate and elastomer seal-on-elastomer seal configurations. The seals were manufactured from S0383-70 silicone elastomer compound. Nominal and off-nominal joint configurations were examined. Both the compression load required to mate the seals and the leak rate observed were recorded while the assemblies were subjected to representative docking system operating temperatures of -58, 73, and 122 F (-50, 23, and 50 C). Both the loads required to fully compress the seals and their leak rates were directly proportional to the test temperature.

High temperature dynamic engine seal technology development

NASA Technical Reports Server (NTRS)

Steinetz, Bruce M.; Dellacorte, Christopher; Machinchick, Michael; Mutharasan, Rajakkannu; Du, Guang-Wu; Ko, Frank; Sirocky, Paul J.; Miller, Jeffrey H.

1992-01-01

Combined cycle ramjet/scramjet engines being designed for advanced hypersonic vehicles, including the National Aerospace Plane (NASP), require innovative high temperature dynamic seals to seal the sliding interfaces of the articulated engine panels. New seals are required that will operate hot (1200 to 2000 F), seal pressures ranging from 0 to 100 psi, remain flexible to accommodate significant sidewall distortions, and resist abrasion over the engine's operational life. This report reviews the recent high temperature durability screening assessments of a new braided rope seal concept, braided of emerging high temperature materials, that shows promise of meeting many of the seal demands of hypersonic engines. The paper presents durability data for: (1) the fundamental seal building blocks, a range of candidate ceramic fiber tows; and for (2) braided rope seal subelements scrubbed under engine simulated sliding, temperature, and preload conditions. Seal material/architecture attributes and limitations are identified through the investigations performed. The paper summarizes the current seal technology development status and presents areas in which future work will be performed.

High Temperature Metallic Seal Development For Aero Propulsion and Gas Turbine Applications

NASA Technical Reports Server (NTRS)

More, Greg; Datta, Amit

2006-01-01

A viewgraph presentation on metallic high temperature static seal development at NASA for gas turbine applications is shown. The topics include: 1) High Temperature Static Seal Development; 2) Program Review; 3) Phase IV Innovative Seal with Blade Alloy Spring; 4) Spring Design; 5) Phase IV: Innovative Seal with Blade Alloy Spring; 6) PHase IV: Testing Results; 7) Seal Seating Load; 8) Spring Seal Manufacturing; and 9) Other Applications for HIgh Temperature Spring Design

Advanced Control Surface Seal Development for Future Space Vehicles

NASA Technical Reports Server (NTRS)

DeMange, Jeffrey J.; Dunlap, Patrick H., Jr.; Steinetz, Bruce M.

2004-01-01

High temperature control surface seals have been identified as a critical technology in the development of future space vehicles. These seals must withstand temperatures of up to 2600 F and protect underlying temperature-sensitive structures (such as actuators and sealing capability by remaining resilient during flight conditions. The current baseline seal, used on the Shuttle orbiters and the X-38 vehicle, consists of a Nextel 312 sheath, an internal Inconel X-750 knitted spring tube, and hand-stuffed Saffil batting. Unfortunately at high temperatures (> 1500 F), the seal resiliency significantly degrades due to yielding and creep of the spring tube element. The permanent set in the seals can result in flow passing over the seals and subsequent damage to temperature sensitive components downstream of the seals. Another shortcoming of the baseline seal is that instances have been reported on Shuttle flights where some of the hand-stuffed Saffil batting insulation has been extracted, thus potentially compromising the seal. In vehicles where the thermal protection systems are delicate (such as with Shuttle tiles), the control surface seals must also limit the amount of force applied to the opposing surfaces. Additionally, in many applications the seals are subjected to scrubbing as control surfaces are actuated. The seals must be able to withstand any damage resulting from this high temperature scrubbing and retain their heat/flow blocking abilities.

Knowledge outcomes within rotational models of social work field education.

PubMed

Birkenmaier, Julie; Curley, Jami; Rowan, Noell L

2012-01-01

This study assessed knowledge outcomes among concurrent, concurrent/sequential, and sequential rotation models of field instruction. Posttest knowledge scores of students ( n = 231) in aging-related field education were higher for students who participated in the concurrent rotation model, and for those who completed field education at a long-term care facility. Scores were also higher for students in programs that infused a higher number of geriatric competencies in their curriculum. Recommendations are provided to programs considering rotation models of field education related to older adults.

20 CFR 369.4 - Inappropriate use of the seal.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 20 Employees' Benefits 1 2011-04-01 2011-04-01 false Inappropriate use of the seal. 369.4 Section... OF THE SEAL OF THE RAILROAD RETIREMENT BOARD § 369.4 Inappropriate use of the seal. The Railroad Retirement Board shall not grant permission for use of the seal in those instances where use of the seal will...

36 CFR 1200.2 - How is each NARA seal designed?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false How is each NARA seal... ADMINISTRATION GENERAL RULES OFFICIAL SEALS How are NARA's Official Seals and Logos Designed and Used? § 1200.2 How is each NARA seal designed? NARA's three official seals are illustrated in Figures 1, 2, and 30. A...

20 CFR 369.4 - Inappropriate use of the seal.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Inappropriate use of the seal. 369.4 Section... OF THE SEAL OF THE RAILROAD RETIREMENT BOARD § 369.4 Inappropriate use of the seal. The Railroad Retirement Board shall not grant permission for use of the seal in those instances where use of the seal will...

28 CFR 803.3 - Use of the seal.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 28 Judicial Administration 2 2011-07-01 2011-07-01 false Use of the seal. 803.3 Section 803.3... SEAL § 803.3 Use of the seal. (a) The Agency seal is used by Agency staff for official agency business as approved by the appropriate Director or designee. (b) Use of the Agency seal by any person or...

28 CFR 803.3 - Use of the seal.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Use of the seal. 803.3 Section 803.3... SEAL § 803.3 Use of the seal. (a) The Agency seal is used by Agency staff for official agency business as approved by the appropriate Director or designee. (b) Use of the Agency seal by any person or...

36 CFR 1200.16 - Will I be penalized for misusing the official seals and logos?

Code of Federal Regulations, 2010 CFR

2010-07-01

... misusing the official seals and logos? 1200.16 Section 1200.16 Parks, Forests, and Public Property NATIONAL ARCHIVES AND RECORDS ADMINISTRATION GENERAL RULES OFFICIAL SEALS Penalties for Misuse of NARA Seals and Logos § 1200.16 Will I be penalized for misusing the official seals and logos? (a) Seals. (1) If you...

36 CFR 1200.2 - How is each NARA seal designed?

Code of Federal Regulations, 2011 CFR

2011-07-01

... 36 Parks, Forests, and Public Property 3 2011-07-01 2011-07-01 false How is each NARA seal... ADMINISTRATION GENERAL RULES OFFICIAL SEALS How are NARA's Official Seals and Logos Designed and Used? § 1200.2 How is each NARA seal designed? NARA's three official seals are illustrated in Figures 1, 2, and 30. A...

36 CFR 1200.16 - Will I be penalized for misusing the official seals and logos?

Code of Federal Regulations, 2011 CFR

2011-07-01

... misusing the official seals and logos? 1200.16 Section 1200.16 Parks, Forests, and Public Property NATIONAL ARCHIVES AND RECORDS ADMINISTRATION GENERAL RULES OFFICIAL SEALS Penalties for Misuse of NARA Seals and Logos § 1200.16 Will I be penalized for misusing the official seals and logos? (a) Seals. (1) If you...

Seals/Secondary Fluid Flows Workshop 1997; Volume II: HSR Engine Special Session

NASA Technical Reports Server (NTRS)

Hendricks, Robert C. (Editor)

2006-01-01

The High Speed Civil Transport (HSCT) will be the largest engine ever built and operated at maximum conditions for long periods of time. It is being developed collaboratively with NASA, FAA, Boeing-McDonnell Douglas, Pratt & Whitney, and General Electric. This document provides an initial step toward defining high speed research (HSR) sealing needs. The overview for HSR seals includes defining objectives, summarizing sealing and material requirements, presenting relevant seal cross-sections, and identifying technology needs. Overview presentations are given for the inlet, turbomachinery, combustor and nozzle. The HSCT and HSR seal issues center on durability and efficiency of rotating equipment seals, structural seals and high speed bearing and sump seals. Tighter clearances, propulsion system size and thermal requirements challenge component designers.