Academic literature on the topic 'Seals'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Seals.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Journal articles on the topic "Seals"
1
Miller, Meredith L. "Seals, Joints, Seams, Leaks." Journal of Architectural Education 68, no. 1 (January 2, 2014): 82–93. http://dx.doi.org/10.1080/10464883.2013.817880.
Full text
2
Darden, J. M., E. M. Earhart, and G. T. Flowers. "Comparison of the Dynamic Characteristics of Smooth Annular Seals and Damping Seals." Journal of Engineering for Gas Turbines and Power 123, no. 4 (March 1, 1999): 857–63. http://dx.doi.org/10.1115/1.1383256.
Full textAbstract:
Annular seals are known to enhance rotordynamic stability margins and minimize vibration response levels in high-speed rotating machinery. Theoretical predictions for the rotordynamic characteristics of annular seals exist but additional experimental data is needed to properly anchor these results. NASA’s Marshall Space Flight Center (MSFC) has developed an annular seal test rig and facility to experimentally characterize axially fed annular seals. Annular seals with deliberately roughened stators (i.e., damping seals) have been shown analytically to increase stability margins of rocket engine turbomachinery by reducing the seal’s whirl frequency ratio. The capabilities of MSFC’s annular seal test rig have been enhanced to allow high fluid inlet preswirl testing that is more representative of actual turbopump seal boundary conditions. The purpose of this paper is to describe the effect of this realistic preswirl on the stabilizing capability of both damping and smooth seals. Centered seal results are presented for both a smooth annular seal and a damping seal. These results were obtained for a range of seal pressure differentials, shaft rotational speeds, and two levels of inlet fluid preswirl.
3
Murie, D. J., and D. M. Lavigne. "Interpretation of otoliths in stomach content analyses of phocid seals: quantifying fish consumption." Canadian Journal of Zoology 64, no. 5 (May 1, 1986): 1152–57. http://dx.doi.org/10.1139/z86-174.
Full textAbstract:
Thirteen captive phocid seals (10 grey seals (Halichoerus grypus), 2 harp seals (Phoca groenlandica), and 1 ringed seal (P. hispida)) were fed Atlantic herring (Clupea harengus harengus) in experiments designed to examine the use of otoliths recovered in stomach contents to interpret food consumption of wild seals. The percentage of ingested otoliths recovered in the stomach contents decreased with the time elapsed after feeding; 100% of otoliths were recovered between 0 and 3 h after feeding and 0% were recovered by 12.9 h after feeding. Absence of otoliths in the large intestine of seals having fed 3 to 6 h previous indicated that unrecovered otoliths had been digested (i.e., a complete disappearance of whole otoliths) while in the stomach. A significant relationship was also evident between the state of digestion of a seal's stomach contents, as measured by the proportion of otoliths remaining in skull cases (skull-recovered otoliths), and the duration of time since it had fed. These relationships have potential application in the estimation of daily fish consumption of seals feeding in the wild.
4
Musin, A. "Small lead seals from Drochiczyn and small lead seals of “Drochiczyn type”: new light on the research on medieval “seal tags” in East-Central Europe." Archaeological News 31 (2021): 290–318. http://dx.doi.org/10.31600/1817-6976-2021-31-290-318.
Full textAbstract:
The article argues the commercial and fiscal nature of medieval small lead seals. For the first time, seal tags of the Piast dynasty are attested. Their symbols correlated with Polish Hohlpfennigs. The concentration of Rus’ and Polish seals on the border may indicate its dual jurisdiction. The practice of European small lead seals is regarded as transfers of the Byzantine tradition.
5
Maaß, Eric, and Frederike D. Hanke. "Distance Estimation in Reproduction Tasks in a Harbor Seal (Phoca vitulina)." Water 13, no. 7 (March 30, 2021): 938. http://dx.doi.org/10.3390/w13070938.
Full textAbstract:
Harbor seals commute between haul-out places and feeding grounds close to the shore or in the open ocean, which is considered a low structured environment, at first sight not providing many cues for orientation/navigation. Nevertheless, seals are well-oriented. For returning to a specific location, seals may use both external and internal cues to, for example, perform path integration requiring the integration of distances traveled and angles steered. We herein assessed the seal’s ability to estimate distances, previously swum or unknown, in reproduction tasks. Reproduction tasks refer to an experimental paradigm in which the experimental animal is required to swim a specific distance first and subsequently reproduce this distance, with visual cues present or absent. The seal was able to estimate and then reproduce distances (0.5–18.5 m) with the smallest error below 10% of the actual distance, and its precision was higher with distances repeatedly swum compared to its performance with unfamiliar distances. In the absence of visual cues, the seal’s performance slightly dropped; however, it was still able to perform the task with an error of 21%. In conclusion, distance estimation may help seals to navigate precisely towards their goals, even if, for example, visual information is not available.
6
You, Jia. "Gray seals: the North Sea's great whites?" Science 346, no. 6214 (December 4, 2014): 1196.4–1196. http://dx.doi.org/10.1126/science.346.6214.1196-d.
Full text
7
Drabek, Charles M., and Jennifer M. Burns. "Heart and aorta morphology of the deep-diving hooded seal (Cystophora cristata)." Canadian Journal of Zoology 80, no. 11 (November 1, 2002): 2030–36. http://dx.doi.org/10.1139/z02-181.
Full textAbstract:
An investigation of the heart morphology of 8 male and 15 female hooded seals (Cystophora cristata) revealed that the heart is proportionately large and the aortic bulb is larger than that reported for most seals. Hooded seals of all ages have large hearts (0.64% of the body mass) and the right ventricle is proportionately longer and more muscular than reported for other seals. The bulb of the ascending aorta shows the large-diameter characteristic of seals capable of making long deep dives, and is constricted to a diameter of less than one-third in the descending aorta. In addition, the ascending aorta has a much greater concentration of elastin fibers than does the descending aorta. In combination with the large right ventricle, these features probably serve to increase lung perfusion during the hooded seal's surface recovery, and to maintain a high blood pressure throughout the cardiac cycle during diving bradycardia. That there was no substantive difference in the heart morphology of pups, yearlings, and adults, suggests that these features are important in the development of diving behavior, and agrees with the rapid behavioral and physiological development of hooded seal neonates.
8
Zhang, Guoyuan, Yangyang Zhao, Weigang Zhao, Xiutian Yan, and Maotan Liang. "An experimental study on the cryogenic face seal at different inlet pressures." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 234, no. 9 (December 19, 2019): 1470–81. http://dx.doi.org/10.1177/1350650119896455.
Full textAbstract:
An experimental test system for cryogenic high-speed hydrodynamic non-contact mechanical seals is developed. Based on this system, the performances of seals under different working conditions are studied in detail in this paper. With the experimental results, the main performances of the seals (such as inlet and outlet temperatures, separated speed, face temperature, friction force, friction coefficient, leakage rate) are obtained, and the relationships of the performances with the inlet fluid pressure, the closing force and the rotational speed are discussed. The results show that the difference between the outlet and inlet temperatures decreases with increasing inlet fluid pressure. As the speed increases, the friction force varies little and remains at a constant value. The friction coefficient of the seal is approximately 0.12 and basically does not change with the speed. The leakage rate is also maintained at approximately 190 g/s. With the increase in the closing force, the friction at the seal’s face does not change greatly, which indicates that the friction at the face is always in a stable state with the seal’s closing force.
9
Kienle, Sarah S., Jezebel Powers, Traci Kendall, Beau Richter, Leann Castle, Gwen Lentes, Daniel Costa, and Rita S. Mehta. "Context Matters: Hawaiian Monk Seals Switch Between Feeding Strategies Depending on Ecological Context." Integrative and Comparative Biology 60, no. 2 (July 29, 2020): 425–39. http://dx.doi.org/10.1093/icb/icaa075.
Full textAbstract:
Synopsis The ability to expand the behavioral repertoire past seemingly rigid morphological features enables animals to succeed in a variety of ecological contexts. The integration of morphology, performance, and behavior produces diverse animal feeding strategies. These different strategies reflect trade-offs between specialization, prey choice, and energetic expenditure, which have important consequences for understanding individual and population-level flexibility in response to environmental change. Here we examined the feeding strategies used by the Hawaiian monk seal (Neomonachus schauinslandi), an endangered marine predator. We tested how Hawaiian monk seal feeding strategies change in response to ecological context, specifically prey size and prey location at different depths. Seven captive Hawaiian monk seals were fed five prey types across a continuum of sizes, and prey were presented at three depths to represent surface, pelagic, and benthic feeding. Hawaiian monk seals used suction feeding and biting strategies, and these strategies were associated with significant differences in behavior and kinematic performance. Hawaiian monk seals used suction feeding most frequently when targeting small to medium prey (0–79% of the seal’s head length) but switched to biting when consuming large prey (>80% of the seal’s head length). These results demonstrate that prey size drives the transition between suction feeding and biting strategies. Seals also switched strategies based on prey position in the water column, primarily using suction feeding when prey were benthic and pelagic, and biting when prey were at the water’s surface. Overall, suction feeding was three to five times faster than biting, required a smaller gape, and used fewer jaw movements, allowing seals to quickly consume numerous small to medium sized prey. In contrast, biting was slower but resulted in the ability to target larger, potentially more energy rich prey. Our results show that Hawaiian monk seals exhibit flexibility in their use of different feeding strategies, which likely facilitates increased foraging success when feeding in spatially and temporally dynamic marine environments.
10
Muir, Shona F., David K. A. Barnes, and Keith Reid. "Interactions between humans and leopard seals." Antarctic Science 18, no. 1 (March 2006): 61–74. http://dx.doi.org/10.1017/s0954102006000058.
Full textAbstract:
In July 2003 Kirsty Brown, a marine biologist at Rothera Research Station (West Antarctic Peninsula), was attacked and drowned by a leopard seal (Hydrurga leptonyx). As a direct consequence, a study was initiated to analyse interactions between humans and leopard seals over the last thirty years utilising humanistic and observational data. The response of leopard seals to humans in different situations was considered using a categorical response scale. Location of the leopard seal and human had the greatest influence on the response of the leopard seal. More specifically, interactions occurring at the ice edge, where leopard seals seek out prey, resulted in the highest response from leopard seals. ‘In water’ interactions, examined through SCUBA dive and snorkelling logs, generally described the seal’s behaviour as displaying curiosity and occurred most frequently at the surface. Although leopard seals approached close to observers and displayed behaviour that appeared aggressive, there were no records of interactions where ‘curious’ leopard seals showed subsequent hunting, or attack behaviour. In contrast, in most interactions (only a few occasions) where physical contact was initiated by a seal, in the form of an attack, the seal was not seen prior to the attack. Kirsty’s incident is the only known account of its kind, given that physical contact occurred at the surface of the water, and the seal had not been seen prior to the attack. This suggests that the commonly cited descriptions of leopard seals interacting with humans in the water are a distinctly different behaviour to that displayed in the attack on Kirsty. Although leopard seal behaviour was generally described by divers as curious, the death of Kirsty Brown indicates that leopard seals can display predatory behaviour towards humans.
Dissertations / Theses on the topic "Seals"
1
Hadley, Gillian Louise. "Recruitment Probabilities and Reproductive Costs for Weddell Seals in Erebus Bay, Antarctica." Thesis, Montana State University, 2006. http://etd.lib.montana.edu/etd/2006/hadley/HadleyG0506.pdf.
Full textAbstract:
The study of life history traits such as age at first reproduction and the evaluation of recruitment probabilities and reproductive costs allow insight regarding the diverse factors and mechanisms shaping reproductive strategies. We investigated these mechanisms using a 26-year mark-resight dataset for Weddell seals (Leptonychotes weddellii) in Erebus Bay, Antarctica. Mean age at first reproduction was 7.62 years of age (SD=1.71), but varied from four to 14 suggesting the presence of important heterogeneity in quality among females. Survival rate was maximized for offspring of age-14 mothers (φ=0.70 [SÊ=0.08]), whereas recruitment probability was highest for pups born to youngest-breeding mothers. For example, probability of recruitment at age 7 was an average of 43% lower for seals born to age-14 mothers than for seals born to age-6 mothers. These results suggest the influence of countervailing selection (where favored genotypes for reproductive success are generally those that are selected against as juveniles). Sea-ice extent affected annual recruitment rates, likely due to cascading effects of oceanographic conditions on marine primary productivity and fluctuations in food availability for female Weddell seals. Results from the reproductive cost analysis strongly supported the presence of reproductive costs to survival (φ was 0.91 for breeders versus 0.94 for nonbreeders). Costs to fecundity were present for first-time breeders (mean probability of breeding the next year was 0.20 lower for first-time breeders than for experienced breeders). Females that delayed breeding until later in life experienced highest reproductive costs to fecundity, possibly due to their inferiority relative to other individuals in the population, again suggesting the influence of heterogeneity in individual quality. From these analyses we have gained insight into 1) the extent of within-population variation in important life-history characteristics for a long-lived species, and 2) the sources of this variation and potential linkages with environmental variables. Keys to future research will be 1) explaining variation in individual quality with random effects models or by using mass as an indicator variable, and 2) more detailed exploration of appropriate climate and sea-ice indices to elucidate linkages between this top trophic level predator and variation in the Antarctic marine environment.
2
Scholze, Stefan Andreas. "Development of Improved Performance Lip-Seals for Seal Clean Bearing Applications." Thesis, University of Wolverhampton, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.502824.
Full text
3
Payne, John Wilson. "Feasibility study of a controllable mechanical seal for reactor coolant pumps." Thesis, Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/47632.
Full textAbstract:
In a nuclear power plant, one of the most important systems for both safety and performance is the reactor cooling system. The cooling system is generally driven by one or more very large centrifugal pumps. Most reactor coolant pumps utilize a multi-stage mechanical face seal system for fluid containment. As a result, these seal systems are critical to safe, continued operation of a nuclear reactor. Without adequate sealing, loss of coolant volume can occur, and a reactor may be forced to shut down, costing the operating utility significantly until it can be brought online again.
The main advantage of mechanical face seals is their self-adjusting properties. These seals are tuned so that they automatically adjust to varying fluid conditions to provide adequate leakage control. Because of the enormous pressures, complicated water chemistry, and possible large temperature transients, the mechanical seals inside a reactor coolant pump must be some of the most robust seals available. In addition, their long service life and continuous operation demand durability and the capability to adjust to a wide range of conditions. However, over time, wear, chemical deposition, or changing operating conditions can alter the face gap, which is the critical geometry between the sealing faces of a seal. An altered face gap can lead to undesirable conditions of too much or not enough leakage, which must be maintained within a certain range to provide lubrication and cooling to the seal faces without resulting in uncontrolled coolant volume loss. Nuclear power plants operate within strict leakage ranges, and long-term effects causing undesirable leakage can eventually necessitate a reactor shutdown if the seal cannot self-adjust to control the leakage.
This document will examine possible causes of undesirable leakage rates in a commonly-used reactor coolant pump assembly. These causes will be examined to determine the conditions which promote them, the physical explanation for their effect on the operation of a mechanical seal, and possible methods of mitigation of both the cause and its effect. These findings are based on previous publications by utilities and technical and incident reports from reactor stations which detail actual incidents of abnormal seal performance and their root causes as determined by the utilities. Next, a method of increasing the ability of a mechanical seal to adapt to a wider range of conditions will be proposed. This method involves modifying an existing seal face to include a method of active control. This active control focuses on deliberately deforming one face of the mechanical sealing face pair. This deformation alters the face gap in order to make the fluid conditions inside the face gap more preferable, generating more or less leakage as desired. Two methods of actuation, hydraulic pressure and piezoelectric deformation, will be proposed.
Finally, a model of the actively controlled seal faces will be introduced. This model includes a method of numerically solving the Reynolds equation to determine the fluid mechanics that drive the lubrication problem in the seal face and coupling the solution with a deformation analysis in a finite element model of a seal face. The model solves iteratively until a converged solution of a sealed pressure distribution, a resulting face deformation, and a calculated leakage rate is reached. The model includes a study of the effects of induced deformation in the seal via both hydraulic and piezoelectric actuation and the ability of this deformation to control the leakage rate.
4
Egan, Geoffrey. "Provenanced leaden cloth seals." Thesis, University College London (University of London), 1988. http://discovery.ucl.ac.uk/1349956/.
Full textAbstract:
This thesis considers the leaden seals which were attached to textiles from the late 14th- to the early 19th century in England as part of a system of industrial regulation and taxation. Almost all of the 1,345 seals and related items which are described here individually were recovered from the ground. This total comprises all the English seals examined which refer to their place of origin in the legends (many of these are alnage seals), all the known English seals of medieval date, and the English matrices for the cloth seals. The unsorted information about each item is presented, just as recorded, in Appendix 1. The historical context and development of cloth sealing in this country are discussed, and a chronological framework for the various stamped devices and forms of seal is proposed. Following a more detailed account of the known medieval seals are brief summaries of the main aspects of local textile industries and a synthesized description of the recorded seals county by county. A concluding section assesses the information provided by the known seals, and the degree of correspondence with data from historical sources. Directions for future studies are suggested. Further appendices provide statistical tables and maps of documentary-based information on levels of textile production at different periods, detailed discussions of the provenances and findspots of the recorded seals, an account of the largest known group of English seals, and documentary evidence for the dating of some of the seals from Norfolk. For the first time information has been presented systematically, and assessed in detail, both on the extent of survival and on the potential academic value of cloth seals found during excavations.
5
Gamal, Eldin Ahmed Mohamed. "Leakage and rotordynamic effects of pocket damper seals and see-through labyrinth seals." Texas A&M University, 2007. http://hdl.handle.net/1969.1/85848.
Full textAbstract:
This dissertation discusses research on the leakage and rotordynamic characteristics
of pocket damper seals (PDS) and see-through labyrinth seals, presents and evaluates
models for labyrinth seal and PDS leakage and PDS force coefficients, and compares
these seals to other annular gas seals. Low-pressure experimental results are used
alongside previously-published high-pressure labyrinth and PDS data to evaluate the
models. Effects of major seal design parameters; blade thickness, blade spacing, blade
profile, and cavity depth; on seal leakage, as well as the effect of operating a seal in an
off-center position, are examined through a series of non-rotating tests. Two
reconfigurable seal designs were used, which enabled testing labyrinth seals and PDS
with two to six blades.
Leakage and pressure measurements were made with air as the working fluid on
twenty-two seal configurations. Increasing seal blade thickness reduced leakage by the
largest amount. Blade profile results were more equivocal, indicating that both profile
and thickness affected leakage, but that the influence of one factor partially negated the
influence of the other. Seal leakage increased with increased eccentricity at lower
supply pressures, but that this effect was attenuated for higher pressure drops. While
cavity depth effects were minor, reducing depths reduced leakage up to a point beyond
which leakage increased, indicating that an optimum cavity depth existed. Changing
blade spacing produced results almost as significant as those for blade thickness,
showing that reducing spacing can detrimentally affect leakage to the point of negating the benefit of inserting additional blades. Tests to determine the effect of PDS partition
walls showed that they reduce axial leakage. The pressure drop was found to be highest
across the first blade of a seal for low pressure drops, but the pressure drop distribution
became parabolic for high pressure drops with the largest drop across the last blade.
Thirteen leakage equations made up of a base equations, a flow factor, and a kinetic
energy carryover factor were examined. The importance of the carryover coefficient
was made evident and a modified carryover coefficient is suggested. Existing fullypartitioned
PDS models were expanded to accommodate seals of various geometries.
6
Huang, Yuli. "Elastohydrodynamic model of hydraulic rod seals with various rod surfaces." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53061.
Full textAbstract:
The reduction or elimination of leakage of hydraulic fluid from fluid power systems is considered a fundamental prerequisite for the expanded use of fluid power. There is also a need to reduce seal friction to both reduce energy dissipation and eliminate control problems. These seals are developed through empirical means at the present time, since the fundamental physics of seal operation has been unclear.
This research develops numerical models for analyzing reciprocating hydraulic rod seals with various rod surfaces. These models consist of coupled fluid mechanics, contact mechanics and deformation analyses. Both flooded and starved lubrication boundary conditions are applied.
For seals with a smooth rod and a plunge-ground rod, the model combines a 1-D finite volume Reynolds equation solver with a 2-D axisymmetric finite element deformation and static contact mechanics analyses, and a Greenwood-Williamson contact mechanics analysis with rod motion. Leakage and friction, along with sealing zone details with the plunge-ground rod are compared with those with the smooth rod. The influence of rod surface finish on seal performance is investigated and explained, under both flooded and starved conditions
For seals with a micro-patterned rod, the model consists of finite volume Reynolds equation solver, finite element deformation and static contact mechanics analyses and a Greenwood-Williamson dynamic contact mechanics analysis. This model is able to handle rod surface pattern with 3-dimensional geometrics. Simulations with different micro-pattern geometries are performed to analyze the fundamental mechanism of surface pattern effects on seal operation. Again, both flooded and starved conditions are applied and the results for both cases are compared and analyzed.
7
Liu, Yin Miao. "Visually sealed and digitally signed electronic documents : building on Asian tradition." Thesis, Queensland University of Technology, 2004. https://eprints.qut.edu.au/15967/1/Yin-Miao_Liu_Thesis.pdf.
Full textAbstract:
E-commerce has developed through the use of digital signatures, employing various forms of Public Key Infrastructure (PKI) to ensure the secure usage of digital signatures. Digital signatures are designed to facilitate the functions of traditional seals and handwritten signatures for the purposes of authentication, data integrity, and non-repudiation within the e-commerce environment. Historically, the authenticity of documentation has always been verified by the application of a recognisable visual stimulus to the document; however, the current digital signature regime overlooks the importance of this analogous sense of visualisation. One of the primary problems with existing digital signatures is that a digital signature does not "feel" like, or resemble, a traditional seal to the human observer, as it does not have a personal, recognisable, or aesthetic sense of visualisation. Currently, digital signatures, such as the OpenPGP (Pretty Good Privacy) digital signature, are attached to the end of an electronic document as a stream of printable ASCII characters. (RFC2440) This appears to the average user as a long, incomprehensible string of random characters offering no sense of identity or ownership by simple visual inspection. Additionally, digital signatures change each time they are applied, in contrast to traditional seals that remain consistent personal identifiers associated with individual signatories. The goal of this research is to promote enhancements to existing digital signature schemes in order to bridge the cultural gap between traditional seals and digital signatures. Culturally friendly features integrated into the digital signature have the potential to increase user acceptability of global e-commerce. This research investigates traditional seal cultures within the context of modern digital signatures, identifying the need to develop a new, culturally friendly, visualised digital signature scheme. The principles behind digital signatures are reviewed and the essential roles and responsibilities of a PKI are addressed. A practical analysis of PKI implementation is also essential. Taiwan is selected as the focus of this research since its heritage is deeply rooted in, and strongly adheres to the Chinese seal culture. The Taiwanese government is in the process of adapting the traditional seal certificate system to the electronic digital signature system. Therefore it is pertinent to review the PKI implementation and digital signatures applications in Taiwan in this study. The purpose of this research is to make the intangible digital signature virtually tangible; i.e., to incorporate visualisation into the current digital signature practice. This research defines new private extensions to the X.509 v3 certificate, recommending that conforming visualised digital signature applications should then be developed to generate and/or recognise visual digital certificates in support of the proposed visualised digital signature scheme. The processes of visualised digital signature creation and of verification through the application of the visualised digital certificate are then explained. This is accompanied by a model of system analysis for developers of conforming implementations of this specification. This allows developers the freedom to select appropriate developing tools. An analysis of this research evaluates the quality of integrity, security, interoperability, performance, and flexibility offered by this proposal.Future directions for furthering research development conclude this dissertation.
8
Liu, Yin Miao. "Visually sealed and digitally signed electronic documents: Building on Asian tradition." Queensland University of Technology, 2004. http://eprints.qut.edu.au/15967/.
Full textAbstract:
E-commerce has developed through the use of digital signatures, employing various forms of Public Key Infrastructure (PKI) to ensure the secure usage of digital signatures. Digital signatures are designed to facilitate the functions of traditional seals and handwritten signatures for the purposes of authentication, data integrity, and non-repudiation within the e-commerce environment. Historically, the authenticity of documentation has always been verified by the application of a recognisable visual stimulus to the document; however, the current digital signature regime overlooks the importance of this analogous sense of visualisation. One of the primary problems with existing digital signatures is that a digital signature does not "feel" like, or resemble, a traditional seal to the human observer, as it does not have a personal, recognisable, or aesthetic sense of visualisation. Currently, digital signatures, such as the OpenPGP (Pretty Good Privacy) digital signature, are attached to the end of an electronic document as a stream of printable ASCII characters. (RFC2440) This appears to the average user as a long, incomprehensible string of random characters offering no sense of identity or ownership by simple visual inspection. Additionally, digital signatures change each time they are applied, in contrast to traditional seals that remain consistent personal identifiers associated with individual signatories. The goal of this research is to promote enhancements to existing digital signature schemes in order to bridge the cultural gap between traditional seals and digital signatures. Culturally friendly features integrated into the digital signature have the potential to increase user acceptability of global e-commerce. This research investigates traditional seal cultures within the context of modern digital signatures, identifying the need to develop a new, culturally friendly, visualised digital signature scheme. The principles behind digital signatures are reviewed and the essential roles and responsibilities of a PKI are addressed. A practical analysis of PKI implementation is also essential. Taiwan is selected as the focus of this research since its heritage is deeply rooted in, and strongly adheres to the Chinese seal culture. The Taiwanese government is in the process of adapting the traditional seal certificate system to the electronic digital signature system. Therefore it is pertinent to review the PKI implementation and digital signatures applications in Taiwan in this study. The purpose of this research is to make the intangible digital signature virtually tangible; i.e., to incorporate visualisation into the current digital signature practice. This research defines new private extensions to the X.509 v3 certificate, recommending that conforming visualised digital signature applications should then be developed to generate and/or recognise visual digital certificates in support of the proposed visualised digital signature scheme. The processes of visualised digital signature creation and of verification through the application of the visualised digital certificate are then explained. This is accompanied by a model of system analysis for developers of conforming implementations of this specification. This allows developers the freedom to select appropriate developing tools. An analysis of this research evaluates the quality of integrity, security, interoperability, performance, and flexibility offered by this proposal.Future directions for furthering research development conclude this dissertation.
9
Gibbens, John Robert. "Demography of Australian fur seals (Arctocephalus pusillus doriferus)." Connect to thesis, 2009. http://repository.unimelb.edu.au/10187/5788.
Full textAbstract:
The Australian fur seal (Arctocephalus pusillus doriferus) population has displayed a relatively slow rate of recovery since being hunted by commercial sealers during the early 19th century. Despite this, population abundance doubled in the past 2 – 3 decades, indicating that the population growth rate has recently increased. Yet, the factors influencing the population’s dynamics are poorly understood, primarily because basic demographic rates are unknown.Female age, survival, fecundity, breeding and physiology were studied at Kanowna Island, Bass Strait, Australia, between 2003 – 2006 by conducting censuses and captures (n = 294). Mark-recapture estimates of pup production were used to validate direct pup counts, allowing a 9-year dataset to be used for calculation of the population growth rate (2.2% p.a.) and investigation of environmental influences on reproductive success. Annual pup production (x = 3108) was synchronous, with 90% of births occurring within 28 days of the median birth date of 23 November. Births occurred earlier in years when pup production and female body condition were high and these factors were correlated with local oceanographic indicators, suggesting that reproductive success is constrained by environmentally-mediated nutritional stress.
Pregnancy was assessed by blood plasma progesterone radioimmunoassay and the pupping status of the same females was observed during breeding season. Despite high mid-gestation pregnancy rates (x = 84%), the birth rate was lower than in other fur seals (x = 53%), suggesting that late-term abortion is common. Lactating females were less likely to pup, indicating that nutrition may be insufficient to support concurrent lactation and gestation.
Age and morphometric data were used to construct body growth, age structure and survivorship models. Adult female survival rates were similar to those of other fur seals (x = 88.5%). A life table was constructed and its age-specific survival and fecundity rates used in a Leslie-matrix model to project the population growth rate (2.2% p.a.) and determine the relative influence of each parameter. The abundance of female non-pups was 6 times greater than that of female pups, which is approximately 50% higher than previous conversion factors used to extrapolate population abundance from pup censuses in Australian fur seals. However, if the non-pup sex ratios of other otariids are considered, the pup:population conversion factor is 4.5.
Compared to a study performed before the recent population increase, the modern population displays similar body growth and fecundity rates but higher survival rates. This suggests that recent population growth resulted from a relaxation of hunting and/or predation mortality rather than from increased food availability. The low population growth rate is attributed to a low birth rate associated with nutritional stress, yet despite this, body growth occurs rapidly. Such characteristics are typical of sea lions rather than fur seals, perhaps because Australian fur seals employ the typical sea lion strategy of using benthic foraging to exploit a continental shelf habitat. The effect of ecological niche on population dynamics in the Otariidae is discussed.
10
Page, Brad, and page bradley@saugov sa gov au. "Niche partitioning among fur seals." La Trobe University. Zoology Department, School of Life Sciences, 2005. http://www.lib.latrobe.edu.au./thesis/public/adt-LTU20060622.153716.
Full textAbstract:
At Cape Gantheaume, Kangaroo Island (South Australia), adult male, lactating female
and juvenile New Zealand (NZ) and Australian fur seals regularly return to the same
colony, creating the potential for intra- and inter-specific foraging competition in nearby
waters. I hypothesised that these demographic groups would exhibit distinct foraging
strategies, which reduce competition and facilitate their coexistence. I analysed the diet
of adult male, adult female and juvenile NZ fur seals and adult male Australian fur seals
and studied the diving behaviour of adult male and lactating female NZ fur seals and the
at-sea movements of juvenile, adult male and lactating female NZ fur seals. Female diet
reflected that of a generalist predator, influenced by prey availability and their
dependant pups� fasting abilities. In contrast, adult male NZ and Australian fur seals
used larger and more energy-rich prey, most likely because they could more efficiently
access and handle such prey. Juvenile fur seals primarily utilised small lantern fish,
which occur south of the shelf break, in pelagic waters. Juveniles undertook the longest
foraging trips and adult males conducted more lengthy trips than lactating females,
which perform relatively brief trips in order to regularly nurse their pups. Unlike lactating
females, some adult males appeared to rest underwater by performing dives that were
characterised by a period of passive drifting through the water column. The large body
sizes of adult males and lactating females facilitated the use of both benthic and pelagic
habitats, but adult males dived deeper and for longer than lactating females, facilitating
vertical separation of their foraging habitats. Spatial overlap in foraging habitats among
the age/sex groups was minimal, because lactating females typically utilised continental
shelf waters and males used deeper water over the shelf break, beyond female foraging
grounds. Furthermore, juveniles used pelagic waters, up to 1000 km south of the
regions used by lactating females and adult males. The age and sex groups in this
study employed dramatically different strategies to maximise their survival and
reproductive success. Their prey and foraging habitats are likely to be shaped by body
size differences, which determine their different physiological constraints and metabolic
requirements. I suggest that these physiological constraints and the lactation
constraints on females are the primary factors that reduce competition, thereby
facilitating niche partitioning.
Books on the topic "Seals"
1
Cossi, Olga. Harp seals. Minneapolis: Carolrhoda Books, 1991.
Find full text
2
Bosiljevac, T. L. SEALs: UDT/SEAL operations in Vietnam. London: Greenhill, 1990.
Find full text
3
Martin, Louise. Seals. Vero Beach, Fla: Rourke Enterprises, 1988.
Find full text
4
Petty, Kate. Seals. New York: Gloucester Press, 1991.
Find full text
5
Wilsdon, Christina. Seals. Pleasantville, NY: Reader's Digest Young Families, 2007.
Find full text
6
David, Stone. Seals. Cambridge, UK: IUCN--the World Conservation Union, 1995.
Find full text
7
Copyright Paperback Collection (Library of Congress), ed. Seals. New York: Jove Books, 2007.
Find full text
8
Copyright Paperback Collection (Library of Congress), ed. Seals. New York: Berkley Pub., 2007.
Find full text
9
Copyright Paperback Collection (Library of Congress), ed. Seals. New York: Berkley Publishing, 2006.
Find full text
10
Sexton, Colleen A. Seals. Minneapolis, MN: Bellwether Media, 2007.
Find full textBook chapters on the topic "Seals"
1
Lewis, Jessica H. "Seals." In Comparative Hemostasis in Vertebrates, 241–48. Boston, MA: Springer US, 1996. http://dx.doi.org/10.1007/978-1-4757-9768-8_20.
Full text
2
Duerr, Rebecca. "Harbor Seals and Northern Elephant Seals." In Hand-Rearing Wild and Domestic Mammals, 132–42. Oxford, UK: Blackwell Publishing Ltd, 2008. http://dx.doi.org/10.1002/9780470385005.ch19.
Full text
3
Bieberle, A., and L. J. Gauckler. "Glass Seals." In Oxygen Ion and Mixed Conductors and their Technological Applications, 389–97. Dordrecht: Springer Netherlands, 2000. http://dx.doi.org/10.1007/978-94-017-2521-7_14.
Full text
4
Netzel, James P. "Mechanical Seals." In Encyclopedia of Tribology, 2209–18. Boston, MA: Springer US, 2013. http://dx.doi.org/10.1007/978-0-387-92897-5_125.
Full text
5
Proctor, Margaret P. "Brush Seals." In Encyclopedia of Tribology, 288–93. Boston, MA: Springer US, 2013. http://dx.doi.org/10.1007/978-0-387-92897-5_133.
Full text
6
Gawlinski, Marek. "Ferrofluid Seals." In Encyclopedia of Tribology, 1069–75. Boston, MA: Springer US, 2013. http://dx.doi.org/10.1007/978-0-387-92897-5_138.
Full text
7
Lynch, Michael, and Kate Bodley. "Phocid Seals." In Zoo Animal and Wildlife Immobilization and Anesthesia, 647–59. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2014. http://dx.doi.org/10.1002/9781118792919.ch46.
Full text
8
Haulena, Martin. "Otariid Seals." In Zoo Animal and Wildlife Immobilization and Anesthesia, 661–72. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2014. http://dx.doi.org/10.1002/9781118792919.ch47.
Full text
9
Klenk, Thomas. "Static Seals." In Encyclopedia of Lubricants and Lubrication, 1972–73. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-22647-2_333.
Full text
10
Pisacane, Giovanni. "Company Seals." In Corporate Governance in China, 91–94. Singapore: Springer Singapore, 2017. http://dx.doi.org/10.1007/978-981-10-3911-9_11.
Full textConference papers on the topic "Seals"
1
Darden, J. Mark, Eric M. Earhart, and George T. Flowers. "Comparison of the Dynamic Characteristics of Smooth Annular Seals and Damping Seals." In ASME 1999 International Gas Turbine and Aeroengine Congress and Exhibition. American Society of Mechanical Engineers, 1999. http://dx.doi.org/10.1115/99-gt-177.
Full textAbstract:
Annular seals are known to enhance rotordynamic stability margins and minimize vibration response levels in high-speed rotating machinery. Theoretical predictions for the rotordynamic characteristics of annular seals exist but additional experimental data is needed to properly anchor these results. NASA’s Marshall Space Flight Center (MSFC) has developed an annular seal test rig and facility to experimentally characterize axially-fed annular seals. Annular seals with deliberately roughened stators (i.e. damping seals) have been shown analyticalty to increase stability margins of rocket engine turbomachinery by reducing the seal’s whirl frequency ratio. The capabilities of MSFC’s annular seal test rig have been enhanced to allow high fluid inlet preswirl testing that is more representative of actual turbopump seal bounder conditions. The purpose of this paper is to describe the effect of this realistic preswirl on the stabilizing capability of both damping and smooth seals. Centered seal results are presented for both a smooth annular seal and a damping seal. These results were obtained for a range of seal pressure differentials, shaft rotational speeds, and two levels of inlet fluid preswirl.
2
Jarrabet, G. P., and L. Lu. "Low Leakage Fiber Metal Seals." In ASME 1992 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1992. http://dx.doi.org/10.1115/92-gt-141.
Full textAbstract:
To improve compressor efficiency, gas turbine engine manufacturers have focused on the need for impermeable low leakage rub strip seal materials. Rub strips are used for clearance control between rotating and stationary components in gas turbine engine compressors and turbines. Fiber metal materials are used in many clearance control seal applications and offer suitable rub characteristics, erosion resistance and temperature capability. The excellent abradability characteristics are related to the seal’s high pore volume of many small but interconnected and open pores. A ceramic foam compositing process was developed for incorporating a closed cell foam into the fiber metal structure. This composite seal material achieves the low leakage needs of advanced engines. The properties of abradability, erosion resistance, oxidation resistance, and low weight inherent in fiber metal compressor seals are maintained. The seals are fabricated by brazing preformed rub strips to backing rings and final machining. Seal fabrication uses conventional processing. The low leakage composite rub strip is an innovative approach to improving compressor efficiency that offers a combination of desirable properties in a seal material.
3
Sun, Faguo, Tianxiang Yu, Weimin Cui, and Xiao Zong. "The seal reliability analysis of oring seals." In 2009 8th International Conference on Reliability, Maintainability and Safety (ICRMS 2009). IEEE, 2009. http://dx.doi.org/10.1109/icrms.2009.5270015.
Full text
4
Meng, Chang, Xuan Wang, Jiajun Sun, Sijun Tao, Wei Wu, Zhihang Wu, Leibin Ni, Xiaolong Shen, Junfeng Zhao, and Weikang Qian. "SEALS." In DAC '22: 59th ACM/IEEE Design Automation Conference. New York, NY, USA: ACM, 2022. http://dx.doi.org/10.1145/3489517.3530464.
Full text
5
Darden, J. Mark, Eric M. Earhart, and George T. Flowers. "Influence of Seal Geometry on the Rotordynamic Characteristics of a Round-Hole Pattern Damping Seal." In ASME 2001 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/detc2001/vib-21635.
Full textAbstract:
Abstract In the design of high-speed rotating machinery, engineers are seeking ways to enhance rotordynamic stability margins while minimizing vibration levels. An attractive option to improve stability margins is the use of annular seals. These seals are versatile because they are effective sealing elements, possess both stiffness and damping characteristics, and are easily incorporated into a pump. Design of an effective seal requires insight into the parameters that can influence its rotordynamic characteristics. Analysis indicates that changes in clearance and taper can significantly affect direct stiffness as well as other seal characteristics. With this in mind, test results are presented for seals with identical round-hole pattern stator surface treatments at two constant radial clearances and one tapered-seal configuration. Testing is performed with a realistic, high inlet fluid preswirl condition that enables an evaluation of a given seal’s stabilizing capacity. All test results presented are for a centered seal condition at multiple shaft speeds and pressure levels. Experimental trends are consistent with theory in that gains in direct stiffness are realized with both a decrease in a seal’s radial clearance and with a convergent-taper. Also, the stabilizing capacity of the seals was significantly influenced by the configurations tested.
6
Gulce, W. L., L. G. Hoang, and T. L. Shinn. "Severe Temperature Service Seals Without Exotic Seal Materials." In Annual Technical Meeting. Petroleum Society of Canada, 1990. http://dx.doi.org/10.2118/90-16.
Full text
7
Haruki, R., T. Horiuchi, H. Yamada, and K. Yamamoto. "Automatic seal verification using three-dimensional reference seals." In Proceedings of 13th International Conference on Pattern Recognition. IEEE, 1996. http://dx.doi.org/10.1109/icpr.1996.546938.
Full text
8
Moreland, J. Alex, Dara W. Childs, and Joshua T. Bullock. "Measured Static and Rotordynamic Characteristics of a Smooth-Stator/Grooved-Rotor Liquid Annular Seal." In ASME 2017 Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/fedsm2017-69036.
Full textAbstract:
Electric submersible pumps utilize grooved-rotor seals to reduce leakage and break up contaminants within the pumped fluid. Additionally, due to their decreased surface area (when compared to a smooth seal), grooved seals decrease the chance of seizure in the case of rotor-stator rubs. Despite their use in industry, the literature does not contain measurements for smooth-stator/circumferentially-grooved-rotor liquid annular seals. This paper presents test results consisting of leakage measurements and rotordynamic coefficients for a smooth-stator/circumferentially-grooved-rotor liquid annular seal. Both static and dynamic performance for the grooved seal are investigated for various imposed pre-swirl ratios, static eccentricities, axial pressure drops, and running speeds. The grooved seals′ static and dynamic performance are compared to those of a smooth seal with identical length, diameter, and radial clearance. Results show that adding grooves reduces leakage at lower speeds (less than 5 krpm) and higher axial pressure drops, but does little at higher speeds. The grooved seal’s direct stiffness is generally negative, which would be detrimental to pump rotordynamics. Furthermore, increasing pre-swirl increases the magnitude of cross-coupled stiffness and increases the whirl frequency ratio. When compared to the smooth seal, the grooved seal has smaller effective damping coefficients, indicative of worse stability characteristics.
9
Joshi, Rutuja Suhas, David C. Roberts, and Hany Ghoneim. "Nonlinear Finite Element Analysis of Radial Lip Seals." In ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-71088.
Full textAbstract:
Oil seals or radial lip seals are widely used in reciprocating, oscillating and rotating shaft applications. The sealability and durability of a lip seal greatly depends on the contact load and contact pressure distribution. It is challenging to find these contact parameters of the seal due to non-linear material behavior and small contact width, therefore numerical simulation can prove to be a viable method. In this paper, to address these challenges and to develop a robust numerical methodology, a Finite Element Model of a lip seal is created in ANSYS APDL. This model includes contact elements to model the lip seal’s contact-fit with certain interference, nonlinear material properties of elastomer and effect of the finger spring molded in the rubber body of the seal. The parameters for two term Mooney Rivlin Model for elastomer are obtained from simple uniaxial tension test. The numerical results demonstrate that the contact load exerted by the composite seal (with spring) is higher than the contact load exerted by elastomer portion of seal alone. It can be implied that the spring augments the radial load and increases the stiffness of the lip, which improves the lip’s sealability and durability. Experimental study is carried to validate the numerical results. The experimental results correspond well with the numerical results.
10
Roche, Brian P. "Bulkhead Seals - A Sealing Solution." In SNAME 11th Propeller and Shafting Symposium. SNAME, 2006. http://dx.doi.org/10.5957/pss-2006-14.
Full textAbstract:
Typical Marine bulkhead seals today utilize a non-metallic seal ring of some kind to seal between the shaft and the seal housing mounted to the bulkhead. The sealing feature can occur continuously, or be actuated when needed. These arrangements can fail to work effectively in practice for a variety of reasons. This paper discusses segmented carbon seals as a viable sealing method Test results are presented, as well as proposed mounting arrangements. A discussion of circumferential seals in general is included.
Reports on the topic "Seals"
1
Minas, Sophie, and Brandon Lampe. PR-591-20700-R01 Wellhead Seals Best Practices. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), April 2021. http://dx.doi.org/10.55274/r0012091.
Full textAbstract:
Wellhead seals are a key component of reservoir and salt-cavern storage wells that function to seal the well from the external environment and separate stored fluids contained within the well. Loss of integrity of these seals or seal failures are a common occurrence in the storage industry. Practical guidelines on how to choose the proper sealing components and prevent seals from failing are generally lacking. In this study, data related to wellhead sealing were compiled through a literature review, discussions with wellhead experts, and a survey distributed to Pipeline Research Council International (PRCI) members and others involved in the industry. Through the evaluation of this data, meaningful parameters involved in successful and failed seals were identified and best practice recommendations were provided on seal selection and wellhead design. There is a related webinar.
2
Lee. L51588 Improved Internal Seals for Pipeline Centrifugal Compressors. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), May 1988. http://dx.doi.org/10.55274/r0010524.
Full textAbstract:
Reviews current technology of internal labyrinth seals and concludes that internal leakage can reduce compressor efficiencies as much as 3 to 6 percent. Discusses limitations on abradable seals with tighter clearances and the effect of compressor surge on both types of seals. Proposes resiliently mounted seals as subject for future investigation to accommodate rotor movement without excessive seal wear.
3
Poerner. PR-015-11211-R01 Mechanical Seal Auxiliary Systems Guideline. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), October 2013. http://dx.doi.org/10.55274/r0010789.
Full textAbstract:
The reliance on centrifugal pumps the world over implies a heavy reliance on mechanical seals. In order to get the highest level of performance from the seals, auxiliary systems are used either to condition the seal operating environment or monitor the systems and detect failures. Current standards already exist that recommend seal auxiliary systems based on certain pump operating conditions, and are widely accepted in the industry both among seal end-users and vendors. And because of their knowledge on the actual seals, the vendors are the primary source for end-users to receive designs and equipment for the auxiliary systems. All of these systems will rely on a number of components that will be selected based on the seals, the operating conditions, and the requirements of the end-user�s facility. Therefore, accurate details for the range of operating conditions of the pump and the product must be supplied to the vendors; that way the vendors can properly specify the seal and the required auxiliary systems. For example, if the product is expected to have considerable contaminants, a filter/separator may be recommended to prevent the contaminants from depositing on the seal faces. If the product will be considerably high in temperature, the recommendation may be to include a cooler to reduce heat build-up in the seals. However, regardless of how well the seal environment is conditioned, it is still expected that the seals will fail. When this failure does occur, additional components may also be selected that will attempt to reduce the amount of product released. These leak detection components are also considered auxiliary system for the seal. Monitoring components can also be used to detect and possibly predict when this failure might occur, thereby, possibly avoiding the unplanned failure altogether. In the future use of seal auxiliary systems, it is this monitoring and trending of operating data that is becoming more critical. Much of the required technology to perform this trending is already in existence; but it is only slowly being adopted, with some possible advances in technology adding to the accuracy and reliability of the trended predictions and detections.
4
Day, Meera. PR-316-17200-R01 Effects of Liquid Contamination on Dry Gas Seal Performance. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), April 2018. http://dx.doi.org/10.55274/r0011478.
Full textAbstract:
This project consisted of a literature review and industry survey. Numerous literature sources were reviewed. Many were found independently, but several were recommended by the project team. The surveys consisted of meetings with individual companies participating in the project. The companies contributed data, reports, and recollections of their experiences with dry gas seals operating with liquid contamination. This report presents a general overview of dry gas seals, as well as a brief summary of the results from the previous dry gas seal study that motivated this project. Next, this paper presents the results from the literature review and industry survey. Liquid contamination failure modes are identified, and success characteristics are discussed.
5
Cassenti, Brice N., and John P. Wesson. Life Prediction of Seals. Fort Belvoir, VA: Defense Technical Information Center, November 1998. http://dx.doi.org/10.21236/ada375804.
Full text
6
Lewan. PR-389-114503-R02 Leak Prevention in CO2 Pipeline Valves and Launches by Correct Seal Material Selection. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), March 2014. http://dx.doi.org/10.55274/r0010537.
Full textAbstract:
PRCI required guidelines for pipeline valve stem seals in CO2 rich applications such as for enhanced oil recovery (EOR) and carbon capture and storage (CCS). In particular, guidance was needed to ascertain when standard O-rings may be used, when a switch to rapid gas decompression (RGD) resistant O-rings is recommended and when O-rings should be replaced by more robust energized lip seals and/or by more robust seal materials. The guidelines would interface with both NORSOK M 710 Rev. 3 and ISO 23936-2, and give specific details on procedures, steps and decisions that have to be taken when attempting to qualify seals for dense phase CO2 use. In order to develop these guidelines, well established sealing compounds having proven RGD resistance were selected for study, along with materials which were not known for their RGD resistance. RGD testing was performed on housed O-rings of each compound using CO2 rich applications. The previous Phase I of the project was carried out with a decompression rate of 20 bar/min over 8 RGD cycles. In this Phase II of the project more severe 70 and 127 bar/min rates were used. Also for the 20 bar/min rates the number of RGD cycles was increased to 50 to see how robust the seal materials could be.
7
Lewan. PR-389-114503-R01 Leak Prevention in CO2 Pipeline Valves and Launches By Correct Seal Material Selection. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), September 2013. http://dx.doi.org/10.55274/r0010086.
Full textAbstract:
Pipeline Research Council International, Inc. (PRCI) required guidelines for pipeline valve stem seals in CO2 rich applications such as for enhanced oil recovery (EOR) and carbon capture and storage (CCS). In particular, guidance was needed to ascertain when standard O-rings may be used, when a switch to rapid gas decompression (RGD) resistant O-rings is recommended and when O-rings should be replaced by more robust energized lip seals and/or by more robust seal materials. The guidelines would interface with both NORSOK M 710 Rev. 3 and ISO 23936-2, and give specific details on procedures, steps and decisions that have to be taken when attempting to qualify seals for dense phase CO2 use. In order to develop these guidelines, two well established sealing compounds having proven RGD resistance were selected for study, along with two materials which were not known for their RGD resistance. RGD testing was performed on housed O-rings of each compound using 4 different gas compositions that cover an appropriate range of field conditions for CO2 applications.
8
Chou, Y. S., and Jeffry W. Stevenson. Refractory Glass Seals for SOFC. Office of Scientific and Technical Information (OSTI), July 2011. http://dx.doi.org/10.2172/1028074.
Full text
9
Testroet, Frank B. Manufacturing Guide for Elastomeric Seals. Fort Belvoir, VA: Defense Technical Information Center, December 1989. http://dx.doi.org/10.21236/ada227511.
Full text
10
Poerner. PR-015-11211-R02 Mechanical Seal Auxiliary Systems Best Practices Summary. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), January 2014. http://dx.doi.org/10.55274/r0010817.
Full textAbstract:
The primary research objective of this project was to summarize the best practices for design, operation, and maintenance of pump mechanical seal auxiliary systems in a reference document for pipeline pump operators. This was achieved by meeting several secondary objectives outlined below. Define the types of mechanical seals and seal auxiliary systems which are used in pipeline stations Determine the reliability of the auxiliary system components as reported by end-users Outline typical and recommended design, operation, and maintenance practices for seal auxiliary systems Based on reliability, design, operation, and maintenance practices identify the best practices for pipeline pump seal auxiliary systems Once these secondary objectives had been achieved, this report was written to summarize the findings.