Thematische Bibliographien / Failsafe mechanism

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Auswahl der wissenschaftlichen Literatur zum Thema „Failsafe mechanism“

Autor: Grafiati

Veröffentlicht am 28. Juni 2021

Zuletzt aktualisiert am 7. Februar 2022

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Zeitschriftenartikel zum Thema "Failsafe mechanism"

Dong, Ke, Quan Quan und W. Murray Wonham. „Failsafe Mechanism Design for Autonomous Aerial Refueling using State Tree Structures“. Unmanned Systems 07, Nr. 04 (17.09.2019): 261–79. http://dx.doi.org/10.1142/s2301385019500109.

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Autonomous Aerial Refueling (AAR) is vulnerable to various failures and involves cooperation among autonomous receivers, tankers and remote pilots. Dangerous flight maneuvers may be executed when unexpected failures or command conflicts happen. To solve this problem, a failsafe mechanism based on State Tree Structures (STS) is proposed. The failsafe mechanism is a control logic that guides what subsequent actions the autonomous receiver should take, by observing real-time information of internal low-level subsystems such as guidance and drogue&probe and external instructions from tankers and pilots. To generate such a controller using STS, the AAR procedure is decomposed into several modes, and safety issues related with seven low-level subsystems are summarized. Then common functional demands and safety requirements are textually described. On this basis, the AAR plants and specifications are modeled by STS, and a supervisor is synthesized to control the AAR model. To prove its feasibility and correctness, a simulation environment incorporating such a logic supervisor is built and tested. The design procedures presented in this paper can be used in decision-making strategies for similar flight tasks. Supporting materials can be downloaded in Github, [ https://github.com/KevinDong0810/Failsafe-Design-for-AAR-using-STS ] including related software, input documents and output files.

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Quan, Quan, Zhiyao Zhao, Liyong Lin, Peng Wang, Walter Murray Wonham und Kai-Yuan Cai. „Failsafe mechanism design of multicopters based on supervisory control theory“. IET Cyber-Systems and Robotics 2, Nr. 1 (01.03.2020): 31–42. http://dx.doi.org/10.1049/iet-csr.2019.0039.

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Yip, Hon Yan K., Annabel Chee, Ching-Seng Ang, Sung-Young Shin, Lisa M. Ooms, Zainab Mohammadi, Wayne A. Phillips et al. „Control of Glucocorticoid Receptor Levels by PTEN Establishes a Failsafe Mechanism for Tumor Suppression“. Molecular Cell 80, Nr. 2 (Oktober 2020): 279–95. http://dx.doi.org/10.1016/j.molcel.2020.09.027.

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Braglia, Priscilla, Junya Kawauchi und Nick J. Proudfoot. „Co-transcriptional RNA cleavage provides a failsafe termination mechanism for yeast RNA polymerase I“. Nucleic Acids Research 39, Nr. 4 (22.10.2010): 1439–48. http://dx.doi.org/10.1093/nar/gkq894.

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Blume, Karin E., Szabolcs Soeroes, Michaela Waibel, Hildegard Keppeler, Sebastian Wesselborg, Martin Herrmann, Klaus Schulze-Osthoff und Kirsten Lauber. „Cell Surface Externalization of Annexin A1 as a Failsafe Mechanism Preventing Inflammatory Responses during Secondary Necrosis“. Journal of Immunology 183, Nr. 12 (09.12.2009): 8138–47. http://dx.doi.org/10.4049/jimmunol.0902250.

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Casilag, Fiordiligie, Anne Lorenz, Jonas Krueger, Frank Klawonn, Siegfried Weiss und Susanne Häussler. „The LasB Elastase of Pseudomonas aeruginosa Acts in Concert with Alkaline Protease AprA To Prevent Flagellin-Mediated Immune Recognition“. Infection and Immunity 84, Nr. 1 (26.10.2015): 162–71. http://dx.doi.org/10.1128/iai.00939-15.

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The opportunistic pathogenPseudomonas aeruginosais capable of establishing severe and persistent infections in various eukaryotic hosts. It encodes a wide array of virulence factors and employs several strategies to evade immune detection. In the present study, we screened the Harvard Medical School transposon mutant library ofP. aeruginosaPA14 for bacterial factors that modulate interleukin-8 responses in A549 human airway epithelial cells. We found that in addition to the previously identified alkaline protease AprA, the elastase LasB is capable of degrading exogenous flagellin under calcium-replete conditions and prevents flagellin-mediated immune recognition. Our results indicate that the production of two proteases with anti-flagellin activity provides a failsafe mechanism forP. aeruginosato ensure the maintenance of protease-dependent immune-modulating functions.

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Lin, Jer-Young, Brandon H. Le, Min Chen, Kelli F. Henry, Jungim Hur, Tzung-Fu Hsieh, Pao-Yang Chen et al. „Similarity between soybean and Arabidopsis seed methylomes and loss of non-CG methylation does not affect seed development“. Proceedings of the National Academy of Sciences 114, Nr. 45 (23.10.2017): E9730—E9739. http://dx.doi.org/10.1073/pnas.1716758114.

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We profiled soybean and Arabidopsis methylomes from the globular stage through dormancy and germination to understand the role of methylation in seed formation. CHH methylation increases significantly during development throughout the entire seed, targets primarily transposable elements (TEs), is maintained during endoreduplication, and drops precipitously within the germinating seedling. By contrast, no significant global changes in CG- and CHG-context methylation occur during the same developmental period. An Arabidopsis ddcc mutant lacking CHH and CHG methylation does not affect seed development, germination, or major patterns of gene expression, implying that CHH and CHG methylation does not play a significant role in seed development or in regulating seed gene activity. By contrast, over 100 TEs are transcriptionally de-repressed in ddcc seeds, suggesting that the increase in CHH-context methylation may be a failsafe mechanism to reinforce transposon silencing. Many genes encoding important classes of seed proteins, such as storage proteins, oil biosynthesis enzymes, and transcription factors, reside in genomic regions devoid of methylation at any stage of seed development. Many other genes in these classes have similar methylation patterns, whether the genes are active or repressed. Our results suggest that methylation does not play a significant role in regulating large numbers of genes important for programming seed development in both soybean and Arabidopsis. We conclude that understanding the mechanisms controlling seed development will require determining how cis-regulatory elements and their cognate transcription factors are organized in genetic regulatory networks.

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Liu, Haiyan, Judith A. Enyeart und John J. Enyeart. „ACTH Inhibits bTREK-1 K+ Channels through Multiple cAMP-dependent Signaling Pathways“. Journal of General Physiology 132, Nr. 2 (28.07.2008): 279–94. http://dx.doi.org/10.1085/jgp.200810003.

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Bovine adrenal zona fasciculata (AZF) cells express bTREK-1 K+ channels that set the resting membrane potential and function pivotally in the physiology of cortisol secretion. Inhibition of these K+ channels by adrenocorticotropic hormone (ACTH) or cAMP is coupled to depolarization and Ca2+ entry. The mechanism of ACTH and cAMP-mediated inhibition of bTREK-1 was explored in whole cell patch clamp recordings from AZF cells. Inhibition of bTREK-1 by ACTH and forskolin was not affected by the addition of both H-89 and PKI(6–22) amide to the pipette solution at concentrations that completely blocked activation of cAMP-dependent protein kinase (PKA) in these cells. The ACTH derivative, O-nitrophenyl, sulfenyl-adrenocorticotropin (NPS-ACTH), at concentrations that produced little or no activation of PKA, inhibited bTREK-1 by a Ca2+-independent mechanism. Northern blot analysis showed that bovine AZF cells robustly express mRNA for Epac2, a guanine nucleotide exchange protein activated by cAMP. The selective Epac activator, 8-pCPT-2′-O-Me-cAMP, applied intracellularly through the patch pipette, inhibited bTREK-1 (IC50 = 0.63 μM) at concentrations that did not activate PKA. Inhibition by this agent was unaffected by PKA inhibitors, including RpcAMPS, but was eliminated in the absence of hydrolyzable ATP. Culturing AZF cells in the presence of ACTH markedly reduced the expression of Epac2 mRNA. 8-pCPT-2′-O-Me-cAMP failed to inhibit bTREK-1 current in AZF cells that had been treated with ACTH for 3–4 d while inhibition by 8-br-cAMP was not affected. 8-pCPT-2′-O-Me-cAMP failed to inhibit bTREK-1 expressed in HEK293 cells, which express little or no Epac2. These findings demonstrate that, in addition to the well-described PKA-dependent TREK-1 inhibition, ACTH, NPS-ACTH, forskolin, and 8-pCPT-2′-O-Me-cAMP also inhibit these K+ channels by a PKA-independent signaling pathway. The convergent inhibition of bTREK-1 through parallel PKA- and Epac-dependent mechanisms may provide for failsafe membrane depolarization by ACTH.

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Wu, Yen-Chi, Geetanjali Chawla und Nicholas Sokol. „let-7-Complex MicroRNAs Regulate Broad-Z3, Which Together with Chinmo Maintains Adult Lineage Neurons in an Immature State“. G3: Genes|Genomes|Genetics 10, Nr. 4 (18.02.2020): 1393–401. http://dx.doi.org/10.1534/g3.120.401042.

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During Drosophila melanogaster metamorphosis, arrested immature neurons born during larval development differentiate into their functional adult form. This differentiation coincides with the downregulation of two zinc-finger transcription factors, Chronologically Inappropriate Morphogenesis (Chinmo) and the Z3 isoform of Broad (Br-Z3). Here, we show that br-Z3 is regulated by two microRNAs, let-7 and miR-125, that are activated at the larval-to-pupal transition and are known to also regulate chinmo. The br-Z3 3′UTR contains functional binding sites for both let-7 and miR-125 that confers sensitivity to both of these microRNAs, as determined by deletion analysis in reporter assays. Forced expression of let-7 and miR-125 miRNAs leads to early silencing of Br-Z3 and Chinmo and is associated with inappropriate neuronal sprouting and outgrowth. Similar phenotypes were observed by the combined but not separate depletion of br-Z3 and chinmo. Because persistent Br-Z3 was not detected in let-7-C mutants, this work suggests a model in which let-7 and miR-125 activation at the onset of metamorphosis may act as a failsafe mechanism that ensures the coordinated silencing of both br-Z3 and chinmo needed for the timely outgrowth of neurons arrested during larval development. The let-7 and miR-125 binding site sequences are conserved across Drosophila species and possibly other insects as well, suggesting that this functional relationship is evolutionarily conserved.

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Perez, Amilcar J., Yann Cesbron, Sidney L. Shaw, Jesus Bazan Villicana, Ho-Ching T. Tsui, Michael J. Boersma, Ziyun A. Ye et al. „Movement dynamics of divisome proteins and PBP2x:FtsW in cells of Streptococcus pneumoniae“. Proceedings of the National Academy of Sciences 116, Nr. 8 (04.02.2019): 3211–20. http://dx.doi.org/10.1073/pnas.1816018116.

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Bacterial cell division and peptidoglycan (PG) synthesis are orchestrated by the coordinated dynamic movement of essential protein complexes. Recent studies show that bidirectional treadmilling of FtsZ filaments/bundles is tightly coupled to and limiting for both septal PG synthesis and septum closure in some bacteria, but not in others. Here we report the dynamics of FtsZ movement leading to septal and equatorial ring formation in the ovoid-shaped pathogen, Streptococcus pneumoniae. Conventional and single-molecule total internal reflection fluorescence microscopy (TIRFm) showed that nascent rings of FtsZ and its anchoring and stabilizing proteins FtsA and EzrA move out from mature septal rings coincident with MapZ rings early in cell division. This mode of continuous nascent ring movement contrasts with a failsafe streaming mechanism of FtsZ/FtsA/EzrA observed in a ΔmapZ mutant and another Streptococcus species. This analysis also provides several parameters of FtsZ treadmilling in nascent and mature rings, including treadmilling velocity in wild-type cells and ftsZ(GTPase) mutants, lifetimes of FtsZ subunits in filaments and of entire FtsZ filaments/bundles, and the processivity length of treadmilling of FtsZ filament/bundles. In addition, we delineated the motion of the septal PBP2x transpeptidase and its FtsW glycosyl transferase-binding partner relative to FtsZ treadmilling in S. pneumoniae cells. Five lines of evidence support the conclusion that movement of the bPBP2x:FtsW complex in septa depends on PG synthesis and not on FtsZ treadmilling. Together, these results support a model in which FtsZ dynamics and associations organize and distribute septal PG synthesis, but do not control its rate in S. pneumoniae.

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Mehr Quellen

Dissertationen zum Thema "Failsafe mechanism"

Hýbl, Matouš. „Dvoukanálový kontrolér krokových motorů“. Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2021. http://www.nusl.cz/ntk/nusl-442448.

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Cílem této práce je vývoj dvoukanálového kontroléru krokových motorů. V rámci práce je popsán jak vývoj elektroniky, tak vývoj příslušného software. Elektronika kontrolŕu je založena na mikrokontroléru STM32F405 a driverů krokových motorů vyráběných firmou Trinamic. Pro komunikaci s nadřazenými systémy je implementován protokol CANOpen a sběrnice I\textsuperscript{2}C a USB. Elektronika byla navržena v software KiCAD and využívá čtyřvrstvého plošného spoje a moderních výrobních technologií. Co se týká software, byl vyvinut jak firmware pro mikrokontrolér, tak software pro ovládání kontroléru. Obě části software využívají programovacího jazyka Rust, který se zaměřuje na bezpečnost práce s pamětí, rychlost a zero-cost abstrakce. Sekundárním cílem této práce je ukázat, jak lze tento programovací jazyk s výhodou použít pro programování nízkoúrovňového embedded software. Firmware kontroléru implementuje nezávislé řízení pohybu obou os kontroléru a to jak v rychlostním, tak v pozičním režimu a zároveň implementuje bezpečnostní funkce pro případy selhání komunikace. Výsledný kontrolér by měl být použit v rámcí výzkumné skupiny Robotiky a Umělé Inteligence a studenty na Ústavu Automatizace FEKT VUT.

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Ricardo, Bruno Assunção. „Safety mechanisms for the reliable operation of 3D vehicles“. Master's thesis, 2017. http://hdl.handle.net/10071/14024.

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The safety and reliability of unmanned vehicles is a growing concern in our modern society. This work proposes and implements mechanisms to minimize risks in the operation of 3D vehicles. A brief analysis is performed to identify high priority risks and low complexity solutions are proposed in order to avoid or minimize their impact. To cope with critical power failures, an autonomous current monitoring system was studied and implemented after analyzing two different techniques: resistive and magnetic current sensing. Furthermore, a fall detection system capable of detecting rotational and free falls was developed and evaluated. Lastly, an obstacle detection and avoidance system relying on multiple smart sensors was proposed. Several simulation tests were performed for different velocities to obtain processing delays and stopping times and thus, the minimal safe flying distance for the avoidance of obstacles.
A segurança na operação fiável de veículos não tripulados é uma preocupação crescente na nossa sociedade moderna. Este trabalho propõe e implementa mecanismos para minimizar os riscos no manuseamento destes veículos. Uma breve análise é realizada para identificar os componentes com maior risco de ocorrerem problemas e soluções de baixa complexidade são propostas a fim de evitar ou minimizar o seu impacto. Para lidar com falhas de energia críticas, um sistema de monitorização de corrente foi estudado e implementado após analisar duas técnicas diferentes: detecção de corrente resistiva e magnética. Além disso, foi desenvolvido e avaliado um sistema de detecção de quedas rotacionais e livres. Por último, foi proposto um sistema de detecção e anti-colisão de obstáculos baseado em múltiplos sensores inteligentes. Diversos testes de simulação foram realizados para obter atrasos de processamento e tempos de travagem. Deste modo foi possível calcular a distância de segurança mínima de travagem face à detecção de um obstáculo.

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Buchteile zum Thema "Failsafe mechanism"

„he need never have made himself before she spoke. What she expects, rightly, is that her utterance will act as a prompt, making him recall parts of the book that he had previously forgotten, and construct the assumptions needed to understand the allusion. In both these examples Mary makes assumptions about what assumptions are, or will be, manifest to Peter. Peter trusts that the assumptions he spontaneously makes about the church and about Sense and Sensibility, which help him understand Mary’s utterances, are those she expected him to make. To communicate success-fully, Mary had to have some knowledge of Peter’s cognitive environment. As a result of their successful communication, their mutual cognitive environment is enlarged. Note that symmetrical co-ordination and mutual knowledge do not enter into the picture at all. The most fundamental reason for adopting the mutual-knowledge framework, as for adopting the code model, is the desire to show how successful communi-cation can be guaranteed, how there is some failsafe algorithm by which the hearer can reconstruct the speaker’s exact meaning. Within this framework the fact that communication often fails is explained in one of two ways: either the code mech-anism has been imperfectly implemented, or there has been some disruption due to ‘noise’. A noiseless, well-implemented code mechanism should guarantee per-fect communication. In rejecting the mutual-knowledge framework, we abandon the possibility of using a failsafe algorithm as a model of human communication. But since it is obvious that the communication process takes place at a risk, why assume that it is governed by a failsafe procedure? Moreover, if there is one conclusion to be drawn from work on artiﬁcial intelligence, it is that most cognitive processes are so complex that they must be modelled in terms of heuristics rather than failsafe algorithms. We assume, then, that communication is governed by a less-than-perfect heuristic. On this approach, failures in communication are to be expected: what is mysterious and requires explanation is not failure but success. As we have seen, the notion of mutual manifestness is not strong enough to salvage the code theory of communication. But then, this was never one of our aims. Instead of taking the code theory for granted and concluding that mutual knowledge must therefore exist, we prefer to look at what kind of assumptions people are actually in a position to make about each other’s assumptions, and then see what this implies for an account of communication. Sometimes, we have direct evidence about other people’s assumptions: for instance, when they tell us what they assume. More generally, because we mani-festly share cognitive environments with other people, we have direct evidence about what is manifest to them. When a cognitive environment we share with other people is mutual, we have evidence about what is mutually manifest to all of us. Note that this evidence can never be conclusive: the boundaries of cogni-tive environments cannot be precisely determined, if only because the threshold between very weakly manifest assumptions and inaccessible ones is unmarked. From assumptions about what is manifest to other people, and in particular about what is strongly manifest to them, we are in a position to derive further“,. In Pragmatics and Discourse, 151. Routledge, 2005. http://dx.doi.org/10.4324/9780203994597-22.

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Konferenzberichte zum Thema "Failsafe mechanism"

Gardner, Ben, Xiaofeng Guan, Ruth Ann Martin und Jack Spain. „Hot Gas Filtration Meeting Turbine Requirements for Particulate Matter“. In ASME Turbo Expo 2005: Power for Land, Sea, and Air. ASMEDC, 2005. http://dx.doi.org/10.1115/gt2005-68925.

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The Power Systems Development Facility (PSDF) is an engineering scale demonstration of advanced coal-fired power systems and high-temperature, high-pressure gas filtration systems. The PSDF was designed at sufficient scale so that advanced power systems and components can be tested in an integrated fashion to provide data for commercial scale-up. The PSDF is funded by the U.S. Department of Energy, the Electric Power Research Institute, Southern Company Services, Kellogg Brown & Root, Inc. (KBR), Siemens-Westinghouse, and Peabody Energy. Gasification at the PSDF is based on KBR’s Transport Gasifier, which is an advanced circulating fluidized-bed gasifier. Hot gas filtration is a critical process in the gasification system to clean up the particulate matter before the synthesis gas (syngas) is fed to the turbine. A Siemens-Westinghouse particulate control device (PCD) is used for syngas cleanup. The PCD contains 91 candle-style filter elements. More than twenty types of filter elements, categorized as monolithic ceramic, composite ceramic, sintered-metal powder, and sintered-metal fiber, have been tested in the gasification environment at the PSDF. Up to January 2005, the longest exposure time for individual filters has been 5783 hours. The particulate loading in the clean syngas during most stable operating periods has been demonstrated to be consistently below 0.1 ppmw, which is the lower detection limit of Southern Research Institute’s sampling system. Safeguard devices (failsafes) have also been tested and developed at the PSDF. Failsafes are used to block the particulate leaking through the PCD in the case of filter element failure to eliminate damage to the turbine. Demonstration of reliable failsafes is a critical factor to the hot gas filtration technology. Several types of currently available failsafes and PSDF-developed failsafes have been tested in the PCD with gasification ash injection to simulate filter element leakage. A typical failsafe was also tested in a device equipped with a quick-open mechanism to simulate a complete filter failure during a test run operation. The testing showed promising results for certain types of failsafes. Further failsafe testing and better understanding of turbine requirements for particulate loading are needed to evaluate the PCD performance and increase readiness towards commercialization of the technology.

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Naija, Mohamed, Rihab Khemiri und Ernesto Exposito. „Failsafe Mechanism to Hazard Analysis and Risk Mitigation in Unmanned Aerial Vehicle based on NCES“. In 15th International Conference on Software Technologies. SCITEPRESS - Science and Technology Publications, 2020. http://dx.doi.org/10.5220/0009887802200227.

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Morrison, Matthew C., und Kenneth J. Bateman. „Transfer and Storage of Molten Salt for the Pyroprocessing of Used Nuclear Fuel“. In ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-36481.

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The transfer and storage of molten salts are being examined to support electrorefining operations at the Idaho National Laboratory. Two important factors that will need to be considered when removing molten salt from either of the two electrorefiners are (1) how to remove salt in a safe and timely manner and (2) how to store significant amounts of electrorefiner salt. A Vacuum Induced Salt Transfer and Storage (VISTAS) system is being evaluated to address these two important factors. This process draws a vacuum in a container through the use of a venturi vacuum pump. The end of a heated drawtube is inserted into the molten salt bath and the molten salt is pulled into the container. A redundant level switch triggered both by the thermal conductivity of the salt and a preset temperature threshold then activates a solenoid, which turns off the argon supply to the venturi vacuum pump, stopping the flow of molten salt. A cooling coil is incorporated into the salt transfer equipment design as a failsafe if the level switch was to fail. A full-scale version of the conceptual design (43 kg capacity) was fabricated to test the vacuum draw salt withdrawal method in an inert argon atmosphere glovebox. In addition, a custom molten salt furnace was designed and fabricated within the glovebox to represent the actual size of an electrorefiner port. Initial testing of the VISTAS system was very successful. The salt was transferred at a consistent rate and the level switch reliably stopped flow. Because the system has a failsafe cooling mechanism, it is considered to have low risk of a salt spill. The container was found to improve storage density, reduce the diffusion of moisture, and reduce material surface area when compared to current options. This system appears to be well suited for this application and further development is recommended.

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Nam, Jung-Han, Chae-Ho Nam, Jong-Moo Lee, Hae-Won Jung, Sim-Kyun Yook und Chang-Ho Cho. „New Design of a Digital CRCS by Introducing LOM“. In 14th International Conference on Nuclear Engineering. ASMEDC, 2006. http://dx.doi.org/10.1115/icone14-89444.

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A Control Rod Control System (CRCS) is one of the most important pieces of equipment in a nuclear power plant because it controls the nuclear reaction by moving the Control Rod Drive Mechanism (CRDM) in the reactor with speed and direction signals from the Reactor Regulating System (RRS). This paper introduces a CRCS with full-duplex configuration and a Local Operator Module (LOM) computer to enhance reliability in comparison to existing simplex systems. The duplex configuration, LOM program, and maintenance test program of the CRCS are explained in detail. This duplex system can perform a failsafe changeover in only a few milliseconds, which results in ‘bumpless’ CRDM coil current control. In particular, because all the control cards are hot-swappable and power converter modules are drawer type, the operator can replace a malfunctioning module without a system shutdown. For ease of operation, the CRCS has its own panel computer called Local Operator Module (LOM) which has a monitoring program installed. The LOM shows all the CRCS operating information such as urgent/non-urgent alarm status, controller operation status, CRDM coil voltage/current, data logs and detailed event alarms. In the CRCS power cabinet, there is an extra panel for easy and simple module maintenance. If the operator suspects that any module of a power cabinet such as a power control card or a power converter module is abnormal, he has only to place the module in the maintenance panel and run the test program to ascertain the module’s sanity. The operator also can utilize the maintenance panel for spare module testing before the spare module is installed in the system and thus avoid installing a defective module.

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Moe, Sigurd, Olav S. Monsson, Øyvind Rokne, Ajith Kumar und Christina Johansen. „Electric Controls Technology: The Role in Future Subsea Systems“. In Offshore Technology Conference Asia. OTC, 2018. http://dx.doi.org/10.4043/28562-ms.

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Abstract This paper prepared for 2018 OTC Offshore Asia explores the current history of electrically driven functionality for subsea production systems. It is expected that co-existence of hybrid electrohydraulic and all-electric functionality will dominate the market for subsea tree and manifold control short term. Electric choke and manifold valve actuation offer many advantages as proved successfully during the last 16 years, e.g. related to modularity and flexibility, with zero discharge, with high operational speed and high positioning accuracy, along with CAPEX and OPEX benefits. Performance of systems such as Statoil's Asgard Subsea Gas Compressor is a game changer that will make all-electric valve control base case also for future subsea processing plants. Reliability & Availability concerns were the major concerns by many operators for not switching to all-electric technology. The excellent reliability of trickle charged batteries in subsea systems, combined with modern safety electronics eliminate the traditional actuator spring as failsafe mechanism power source. All of this has simplified the equipment, reduced the size, and enables continuous equipment status monitoring. Competitive all-electric systems are expected to be introduced in stages, starting with infill wells. This will eliminate the risk of new technology for the best business cases, being long distance gas fields, water injectors and deep water systems. Subsea all-electric solutions benefit from general technology developments in other industries. Full utilization is however slow in the subsea market, hampered by current rules and regulations, risk aspects and conservative mindsets. All-electric solutions need Champions and a continued successful staged development initiatives to realize their full potential for significantly reducing subsea field development capital and operational cost.

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Petersen, Christian, Ola Strand, Espen Johansen, Dag Almar Hansen, Dag Ketil Fredheim und Per Ohlckers. „PACT - One Step Closer to Well Control Autonomy“. In SPE Annual Technical Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/206274-ms.

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Abstract Pressure control have been going through steps of evolution. In the highlight of safety, reliability and control, the systems have been sturdy withstanding massive pressure and environmental impact to last the time of estimated life of well. Design have been emphasizing on sturdiness rather than intelligence and autonomy. Time moves on, sophistication levels rise in all parts of our industry. Sustainability and lower environmental impact of solutions grow from the young into business planning and democratic policies. Control lines of hydraulic systems posed risks to the environment as well as being costly in structure and maintenance. Condition monitoring helped ensure better maintenance planning and lowered the risk of breakdown, but still left a lot to be desired reaching for self-contained, self learning systems with low installation and maintenance costs, yet the safest approach. The next steps were taken towards electrification and digitization of pressure control systems, making short and undetermined strides over almost two decades. Still, the standards are not following the pace of technological progress. And when someone dares to pilot or demonstrate modern technology applied, the installations and operational procedures of the systems still need expensive distributed lines of power, of signals and control systems to ensure a swift and safe operation. The fly-by-wire principle applied in oil & gas is the operate-by-costly-technology-and-environmental-impact-lines. With the introduction of new and breaking technology in energy harvesting and storage, the playing field opens up towards fully automated systems with no need for expensive power lines or hydraulic control lines. The safety will be taken care of also off-grid, fully digitized. Should cabling of instrument signals be damaged, the system of tomorrow will still be up to par with the Safety Integrity Levels needed. New super-capacitors with an extra dense storage capacity being developed in partnership between the industry and the University of southeast Norway combined with an extremely low energy consuming actuation system with the fastest failsafe mechanism ever will ensure safety in all modes of operation, even with all lines down or consumed by flames. The paper aims to show how the technology works and underline why it will take a place in the future of well control and production.

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