Добірка наукової літератури з теми "ERF.E subclass"
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Статті в журналах з теми "ERF.E subclass":
1
Neubauer, Olivia, Anja Alfandega, Janna Schoknecht, Ulrich Sternberg, Anne Pohlmann, and Thomas Eitinger. "Two Essential Arginine Residues in the T Components of Energy-Coupling Factor Transporters." Journal of Bacteriology 191, no. 21 (August 28, 2009): 6482–88. http://dx.doi.org/10.1128/jb.00965-09.
Анотація:
ABSTRACT Energy-coupling factor (ECF) transporters, a recently discovered class of importers of micronutrients, are composed of a substrate-specific transmembrane component (S component) and a conserved energy-coupling module consisting of a transmembrane protein (T component) and pairs of ABC ATPases (A proteins). Based on utilization of a dedicated (subclass I) or shared (subclass II) energy-coupling module, ECF systems fall into two subclasses. The T components are the least-characterized proteins of ECF importers, and their function is essentially unknown. Using RcBioN and LmEcfT, the T units of the subclass I biotin transporter (RcBioMNY) of a gram-negative bacterium and of the subclass II folate, pantothenate, and riboflavin transporters of a lactic acid bacterium, respectively, we analyzed the role of two strongly conserved short motifs, each containing an arginine residue. Individual replacement of the two Arg residues in RcBioN reduced ATPase activity, an indicator of the transporter function, by two-thirds without affecting the modular assembly of the RcBioMNY complex. A double Arg-to-Glu replacement destroyed the complex and abolished ATPase activity. The corresponding single mutation in motif II of LmEcfT, as well as a double mutation, led to loss of the T unit from the subclass II ECF transporters and inactivated these systems. A single Arg-to-Glu replacement in motif I, however, abolished vitamin uptake activity without affecting assembly of the modules. Our results indicate that the conserved motif I in T components is essential for intramolecular signaling and, in cooperation with motif II, for subunit assembly of modular ECF transporters.
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Comelli, Raúl N., Elina Welchen, Hye Jin Kim, Jong Chan Hong, and Daniel H. Gonzalez. "Delta subclass HD-Zip proteins and a B-3 AP2/ERF transcription factor interact with promoter elements required for expression of the Arabidopsis cytochrome c oxidase 5b-1 gene." Plant Molecular Biology 80, no. 2 (June 6, 2012): 157–67. http://dx.doi.org/10.1007/s11103-012-9935-9.
3
Mounteer, Ann H., Flávia ML Passos, Arnaldo Chaer Borges, and Daison Olzany Silva. "Detecting structural and functional differences in activated sludge bacterial communities originating from laboratory treatment of elementally and totally chlorine-free bleaching effluents." Canadian Journal of Microbiology 48, no. 3 (March 1, 2002): 245–55. http://dx.doi.org/10.1139/w02-006.
Анотація:
The ability to differentiate functional and structural diversity of bacterial communities present in activated sludges adapted to elementally (ECF) and totally (TCF) chlorine-free bleaching effluents was evaluated. Community function was evaluated through substrate utilization patterns in BiologGN®microplates, and taxonomic structure was evaluated by fluorescent in situ hybridization using probes targeting the Eubacteria; the alpha, beta, and gamma subclasses of the Proteobacteria; and gram-positive bacteria with high GC content. Over 6-week sampling periods, ECF- and TCF-adapted sludge bacterial communities presented reproducible substrate utilization patterns that through principal components (PCs) analysis, separated the ECF samples from the TCF samples. Application of the fluorescent in situ hybridization technique was complicated by the intense autofluorescence of the bleaching effluent sludge samples that interfered with detection of specific hybridization signals. The most notable difference in community structure detected using the chosen set of probes was the relatively greater proportion of cells of the alpha subclass in TCF sludge (27%) than in ECF sludge (6%). Nonspecific hybridization with beta and gamma probes was relatively high, but both sludges appeared to have similar proportions of cells of the beta (2022%) and gamma (1112%) subclasses. The two sludges presented relatively few gram-positive cells with high GC content (<0.2% of eubacterial counts). Differences in both metabolic potential and taxonomic structure of the microbial communities in the ECF- and TCF-activated sludges were detected. The kinetics of the development of these differences in treatment plants and their relationships with treatment efficiency and production process conditions should now be evaluated.Key words: activated sludge, bleaching effluents, Biolog, in situ hybridization.
4
Defize, L. H., J. Boonstra, J. Meisenhelder, W. Kruijer, L. G. Tertoolen, B. C. Tilly, T. Hunter, P. M. van Bergen en Henegouwen, W. H. Moolenaar, and S. W. de Laat. "Signal transduction by epidermal growth factor occurs through the subclass of high affinity receptors." Journal of Cell Biology 109, no. 5 (November 1, 1989): 2495–507. http://dx.doi.org/10.1083/jcb.109.5.2495.
Анотація:
Many cell types display two classes of epidermal growth factor receptor (EGFR) as judged from EGF binding studies; i.e., a major class of low affinity EGFR and a minor class of high affinity EGFR. We have studied their respective contribution to the cascade of events elicited by EGF in human A431 carcinoma cells, using anti-EGFR mAb 2E9. This antibody specifically blocks EGF binding to low affinity EGFR, without activating receptors in intact cells, and thus enables us to study the effects of exclusive EGF binding to high affinity EGFR. We show that blocking of low affinity EGFR by mAb 2E9 has almost no effect on the activation of the receptor protein-tyrosine kinase by EGF, suggesting that EGFR kinase activation occurs exclusively through the subclass of high affinity EGFR (5-10%). In addition, we provide evidence that high affinity EGFR exists both in monomeric and dimeric forms, and that cross-phosphorylation of low affinity EGFR by high affinity EGFR may take place in dimers of both receptor types. We demonstrate that the following early cellular response to EGF are also unimpaired in the presence of mAb 2E9: (a) inositol phosphate production, (b) release of Ca2+ from intracellular stores, (c) rise in intracellular pH, (d) phosphorylation of EGF on threonine residue 654, (e) induction of c-fos gene expression, and (f) alteration in cell morphology. As possible nonspecific side effects, we observed that the EGF induced Ca2+ influx and fluid-phase pinocytosis were inhibited in A431 cells in the presence of mAb 2E9. We conclude, therefore, that the activation of the EGFR signal transduction cascade can occur completely through exclusive binding of EGF to the subclass of high affinity EGFR.
5
Defize, L. H., D. J. Arndt-Jovin, T. M. Jovin, J. Boonstra, J. Meisenhelder, T. Hunter, H. T. de Hey, and S. W. de Laat. "A431 cell variants lacking the blood group A antigen display increased high affinity epidermal growth factor-receptor number, protein-tyrosine kinase activity, and receptor turnover." Journal of Cell Biology 107, no. 3 (September 1, 1988): 939–49. http://dx.doi.org/10.1083/jcb.107.3.939.
Анотація:
The epidermal growth factor receptor (EGF-R) of human A431 cells bears an antigenic determinant that is closely related to the human blood group A carbohydrate structure. Labeling studies with blood group A reactive anti-EGF-R monoclonal antibodies and various lectins revealed that A431 cultures are heterogeneous with respect to blood group A expression. We have isolated clonal variants of these cells that either express (A431A+ cells) or completely lack (A431A- cells) the blood group A specific N-acetyl-D-galactosamine (GalNAc) residue. We show that this difference is due to the absence of a UDP-GalNAc:Gal transferase activity in A431A- cells. Subsequently, we have compared EGF-R functioning in these cell lines. Scatchard analysis of EGF-binding shows that in A431A- cells 6.3% of the EGF-R belongs to a high affinity subclass (Kd = 0.4 nM) while in A431A+ this subclass represents only 3.2% of the total receptor pool. The elevated level of high affinity receptors in A431A- cells is accompanied by a parallel increase in receptor protein- tyrosine kinase activity. In membrane preparations of A431A- cells, receptor autophosphorylation as well as phosphorylation of a tyrosine-containing peptide substrate is 2-3-fold higher as compared with A431A+ cells. In intact A431A-cells, the difference in receptor activity is measured as a 2-3-fold elevated level of receptor phosphorylation and a 2-3-fold higher abundance of phosphotyrosine in total cellular protein in A431A- cells. In addition, [35S]methionine pulse-chase experiments showed a ligand-independent increase in turnover of EGF-R in A431A- cells: the receptor's half life in these cells is 10 h as compared with 17 h in A431A+ cells. Our results suggest a possible involvement of GalNAc residue(s) in determining EGF-R affinity, protein-tyrosine kinase activity and turnover in A431 cells. Furthermore, our results indicate that high affinity EGF-R are the biologically active species with respect to protein-tyrosine kinase activity.
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Kilic, Mukremin, Pierre Bergeron, Simon Blouin, Gracyn Jewett, Warren R. Brown, and Adam Moss. "White Dwarf Merger Remnants: The DAQ Subclass." Astrophysical Journal 965, no. 2 (April 1, 2024): 159. http://dx.doi.org/10.3847/1538-4357/ad3440.
Анотація:
Abstract Four years after the discovery of a unique DAQ white dwarf with a hydrogen-dominated and carbon-rich atmosphere, we report the discovery of four new DAQ white dwarfs, including two that were not recognized properly in the literature. We find all five DAQs in a relatively narrow mass and temperature range of M = 1.14–1.19 M ⊙ and T eff = 13,000–17,000 K. In addition, at least two show photometric variations due to rapid rotation with ≈10 minute periods. All five are also kinematically old, but appear photometrically young, with estimated cooling ages of about 1 Gyr based on standard cooling tracks, and their masses are roughly twice the mass of the most common white dwarfs in the solar neighborhood. These characteristics are smoking gun signatures of white dwarf merger remnants. Comparing the DAQ sample with warm DQ white dwarfs, we demonstrate that there is a range of hydrogen abundances among the warm DQ population and that the distinction between DAQ and warm DQ white dwarfs is superficial. We discuss the potential evolutionary channels for the emergence of the DAQ subclass, suggesting that DAQ white dwarfs are trapped on the crystallization sequence and may remain there for a significant fraction of the Hubble time.
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Li, Yan, and Yaqiang Wang. "Some new results for $ B_1 $-matrices." Electronic Research Archive 31, no. 8 (2023): 4773–87. http://dx.doi.org/10.3934/era.2023244.
Анотація:
<abstract><p>The class of $ B_1 $-matrices is a subclass of $ P $-matrices and introduced as a generalization of $ B $-matrices. In this paper, we present several properties for $ B_1 $-matrices. Then, the infinity norm upper bound for the inverse of $ B_1 $-matrices is obtained. Furthermore, the error bound for the linear complementarity problem of $ B_1 $-matrices is presented. Finally, some numerical examples are given to illustrate our results.</p></abstract>
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Qi, Jiaqi, and Yaqiang Wang. "Subdirect Sums of $ GSD{D_1} $ matrices." Electronic Research Archive 32, no. 6 (2024): 3989–4010. http://dx.doi.org/10.3934/era.2024179.
Анотація:
<abstract><p>The class of generalized $ SD{D_1} \; \left({GSD{D_1}} \right) $ matrices is a new subclass of $ H $-matrices. In this paper, we focus on the subdirect sum of $ GSD{D_1} $ matrices, and some sufficient conditions to ensure that the subdirect sum of $ GSD{D_1} $ matrices with strictly diagonally dominant $ \left({SDD} \right) $ matrices is in the class of $ GSD{D_1} $ matrices are given. Moreover, corresponding examples are given to illustrate our results.</p></abstract>
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Liu, Yi, Lei Gao, and Tianxu Zhao. "Partially doubly strictly diagonally dominant matrices with applications." Electronic Research Archive 31, no. 5 (2023): 2994–3013. http://dx.doi.org/10.3934/era.2023151.
Анотація:
<abstract><p>A new class of matrices called partially doubly strictly diagonally dominant (for shortly, PDSDD) matrices is introduced and proved to be a subclass of nonsingular $ H $-matrices, which generalizes doubly strictly diagonally dominant matrices. As applications, a new eigenvalue localization set for matrices is given, and an upper bound for the infinity norm bound of the inverse of PDSDD matrices is presented. Based on this bound, a new pseudospectra localization for matrices is derived and a lower bound for distance to instability is obtained.</p></abstract>
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Merchant, J. L., G. R. Iyer, B. R. Taylor, J. R. Kitchen, E. R. Mortensen, Z. Wang, R. J. Flintoft, J. B. Michel, and R. Bassel-Duby. "ZBP-89, a Krüppel-like zinc finger protein, inhibits epidermal growth factor induction of the gastrin promoter." Molecular and Cellular Biology 16, no. 12 (December 1996): 6644–53. http://dx.doi.org/10.1128/mcb.16.12.6644.
Анотація:
We have shown previously that a GC-rich element (GGGGCGGGGTGGGGGG) conferring epidermal growth factor (EGF) responsiveness to the human gastrin promoter binds Sp1 and additional undefined complexes. A rat GH4 cell line expression library was screened by using a multimer of the gastrin EGF response element, and three overlapping cDNA clones were identified. The full-length rat cDNA encoded an 89-kDa zinc finger protein (ZBP-89) that was 89% identical to a 49-kDa human factor, ht(beta), that binds a GTGGG/CACCC element in T-cell receptor promoters. The conservation of amino acids between the zinc fingers indicates that ZBP-89 is a member of the C2H2 zinc finger family subclass typified by the Drosophila Krüppel protein. ZBP-89 is ubiquitously expressed in normal adult tissues. It binds specifically to the gastrin EGF response element and inhibits EGF induction of the gastrin promoter. Collectively, these results demonstrate that ZBP-89 functions as a repressor of basal and inducible expression of the gastrin gene.
Дисертації з теми "ERF.E subclass":
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Ying, Shiyu. "Régulation et rôle des facteurs de transcription de type ERF de la sous-classe E (ERF-E) dans la maturation des fruits climactériques." Electronic Thesis or Diss., Toulouse, INPT, 2023. http://www.theses.fr/2023INPT0141.
Анотація:
Le mûrissement des tomates est un processus finement régulé avec de nombreux changements dynamiques qui concernent les voies du métabolisme primaire et secondaire, la respiration ou encore la signalisation hormonale. Comme les autres fruits climactérique, la tomate connait une transition développementale du stade « pré-maturation » à la phase de maturation qui est associée à une augmentation de la respiration au début de la maturation et à une augmentation de la production autocatalytique d'éthylène. Les facteur de réponse à l'éthylène, de la sous-clade E (ERF.E), ont un profil d'expression fortement associé au mûrissement du fruits de tomate. Les protéines ERF.E de la tomate sont notamment caractérisées par la présence d'un motif N-terminal conservé, qui a été identifié comme cible de la voie N-end rule en condition d’hypoxie chez leurs orthologues d'Arabidopsis. Cette étude dévoile pour la première le rôle positif de ERF.E1 dans la maturation des fruits de la tomate. La surexpression d'ERF.E1 favorise l'initiation du mûrissement, et est accompagnée d'une production avancée d'éthylène et d'une déplétion précoce de l'oxygène dans le gel, par rapport aux lignées WT et KO-erf.e1. ERF.E1 régule positivement les activités promotrices des gènes clés de la maturation, RIN et NOR, ainsi que les gènes de biosynthèse de l'éthylène du système 2. De plus, les résultats ont montré qu’en condition d’hypoxie, ERF.E1 est régulé aux niveaux transcriptionnel et post-traductionnel. En effet, les conditions hypoxiques induisent l’expression d’ERF.E1 et stabilise la protéine ERF.E1. Cette thèse se concentre principalement sur le rôle d'ERF.E1 dans l'initiation de la maturation, grâce à la caractérisation des lignées altéré dans l’expression de ERF.E1 et à l’étude des réseaux d'interaction protéiques potentiels d'ERF.E1Tomato fruit ripening is a finely regulated process with many well-known dynamic changes, from metabolites, color, and respiration rate to hormone level. As a climacteric fruit, tomato fruit experiences a developmental transition characterized by a burst of respiration at the onset of ripening and a rise in autocatalytic ethylene production. Ethylene Response Factors (ERFs) are end mediators of ethylene responses and members of subclade E (ERF.E) of this transcription factor family display remarkable ripening-associated expression patterns in tomato fruit. Notably, tomato ERF.E proteins are characterized by the presence of a consensus N-terminal motif, which has been identified in their Arabidopsis orthologs as the target of the N-end rule pathway under hypoxia. The first outcome of our study is to reveal that initiation of tomato fruit ripening is preceded by a dramatic drop in oxygen levels in locular gel, thus giving a solid physiological marker of ripening initiation. The study also unveils the function of ERF.E1 in tomato fruit ripening showing that overexpression of ERF.E1 promotes the initiation of ripening, by advancing both ethylene production and oxygen depletion event in the gel, compared with the WT and KO-erf.e1 lines. ERF.E1 positively regulates the promoter activities of key ripening genes, RIN and NOR, as well as the ethylene biosynthesis genes involved in System 2 ethylene production. In addition, the data show that ERF.E1 is regulated by hypoxia at both transcriptional and post-translational levels. Hypoxia conditions induce transcription of ERF.E1 and promote ERF.E1 protein stability. Overall, while the study unraveled the role of ERF.E1 in ripening initiation based on the analysis of ERF.E1 impaired lines are altered at the early ripening stages it also uncovered potential proteins interacting with the ERF.E1 network components
Частини книг з теми "ERF.E subclass":
1
Hanson, Robin. "Politics." In The Age of Em. Oxford University Press, 2016. http://dx.doi.org/10.1093/oso/9780198754626.003.0029.
Анотація:
Who is higher status in an em world? Humans are much less competent than ems in most jobs, and so ems see humans and styles and habits associated with humans as lower status. As ems must retire when they can no longer compete with younger workers, retirees are also lower status, as are styles and habits associated with retirees. Also, we have long treated places where people congregate more densely, and the people who congregate there, as higher status. Humans, retirees, and ems away from urban centers all tend to be slower. These features help to make slow speed seem low status to ems. In addition, faster ems tend to have many other features that are today treated as markers of higher status. Faster ems tend to be bosses, to embody more wealth, to host meetings, and to sit at premium locations. Faster ems find it easier to coordinate with each other in contests with slower ems. Fast ems hear of and react to news first, and so more quickly adopt new fashions. As faster em brains embody more capital, impoverished ems are often forced to run at slower speeds. Also, the lives of slower ems seem more like “death,” in the sense that they have a larger chance of ending sooner because of civilization instability. For example, if the em era lasts for 2 objective years, a micro-em experiences only 1 subjective minute during that period. Thus slower ems can naturally seem nearer to death, which seems low status. Thus we have many reasons to expect that ems who run faster are usually seen as higher status. Similarly, during meetings the more centrally located ems, for whom signal delays are smallest, may usually appear to be more central and powerful. Note that as em speeds will tend to clump, this creates a class system of distinct status levels. Today, residents of bigger cities tend to be seen as higher status, and their higher status isn’t much lost when they temporarily visit rural areas. Similarly, em status may not change much during temporary speed changes. It might instead be the typical speed of their clan or subclan that matters most. Slow ems can have the status mark of taking a longer-term bigger-picture view, and a few of them are trusted to manage capital for long-term payoffs.
Тези доповідей конференцій з теми "ERF.E subclass":
1
Surducan, Mihai. "Anti-nephrin autoantibody positivity describes a unique subclass of podocytopathies." In 61st ERA Congress, edited by Rachel Giles. Baarn, the Netherlands: Medicom Medical Publishers, 2024. http://dx.doi.org/10.55788/ad1d4585.
2
Kim, Ji Hye, Dae Sung Kim, In-Beom Jeong, Ji-Woong Son, Mun-Jun Na, and Sun-Joong Kwon. "IgG3 subclass deficiency as a predictive marker of mortality in patients admitted to ICU." In ERS International Congress 2018 abstracts. European Respiratory Society, 2018. http://dx.doi.org/10.1183/13993003.congress-2018.pa2623.
3
Pla, Jordi Juanola, Ramon Boixeda Viu, Isabel Moreno Hernandez, M. Carmen De La Torre Terron, Maria Bartolomé Regué, Anna Serrano Fores, Ainhoa Montero Rodriguez, Elisabet Palomera Fanegas, Mateu Serra Prat, and Jordi Almirall Pujol. "Immunoglobulin G and subclasses in COPD exacerbator phenotype: levels in exacerbation time and clinical stability." In ERS International Congress 2021 abstracts. European Respiratory Society, 2021. http://dx.doi.org/10.1183/13993003.congress-2021.pa3115.
4
Turato, Silvia, Vincent Venturini, Eric Meister, B. Richard Bass, Terry L. Dickson, and Claud E. Pugh. "Deterministic and Probabilistic Assessments of the Reactor Pressure Vessel Structural Integrity: Benchmark Comparisons." In ASME 2003 Pressure Vessels and Piping Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/pvp2003-2190.
Анотація:
The structural integrity assessment of a nuclear Reactor Pressure Vessel (RPV) during accidental conditions, such as loss-of-coolant accident (LOCA), is a major safety concern. Besides Conventional deterministic calculations to justify the RPV integrity, Electricite´ de France (EDF) carries out probabilistic analyses. Since in the USA the probabilistic fracture mechanics analyses are accepted by the Nuclear Regulatory Commission (NRC), a benchmark has been realized between EDF and Oak Ridge Structural Assessments, Inc. (ORSA) to compare the models and the computational methodologies used in respective deterministic and probabilistic fracture mechanics analyses. Six cases involving two distinct transients imposed on RPVs containing specific flaw configurations (two axial subclad, two circumferential surface-breaking, and two axial surface-braking flaw configurations) were defined for a French vessel. In two separate phases, deterministic and probabilistic, fracture mechanics analyses were performed for these six cases.
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Ghosh, Pia, Ingrid Gerhardson, Barbro Dahlen, and Apostolos Bossios. "Increased relative levels of IgG subclasses, mainly IgG3, in patient with bronchiectasis and history of exacerbations; preliminary results from a single tertiary center." In ERS International Congress 2019 abstracts. European Respiratory Society, 2019. http://dx.doi.org/10.1183/13993003.congress-2019.pa2765.
6
Bezdikian, Georges, Dominique Moinereau, and Claude Faidy. "RPV Integrity Assessment: Comparison Between 3 Loops and 4 Loops Studies." In ASME/JSME 2004 Pressure Vessels and Piping Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/pvp2004-2721.
Анотація:
For the French utility (Electricite de France–EDF), Nuclear Energy represents 75% of generation of the total electric energy in France. Total nuclear electricity were generated mainly from Nuclear Power plants stations, 34 PWR NPPs 3-loop Reactors- 900 MWe, 20 PWR NPPs 4-loop Reactors- 1300 MWe and 4 PWR NPPs 4-loop Reactors- 1450 MWe. The 3-loop Reactor Pressure Vessel (RPV) integrity assessment, applied on 34 PWR NPPs Reactors, involved the verification of the integrity of the component under the most severe conditions of situation, and the result obtained was the justification of the 900 MWe RPV life management for at least 40 years and to prepare the projection beyond 40 years. Since 2000, in the continuity of these results, the studies were carried out on the 20 PWR NPPs 4-loop 1300 MWe Reactor Pressure Vessels, and the recent results obtained show the demonstration of the integrity of the RPV, in the most severe conditions of loading in relation with RTNDT (Reference Nil Ductility Transition Temperature), and other major parameters. This approach is based on specific mechanical safety studies on the RPV to demonstrate the absence of the risk of failure by brittle fracture. For these mechanical studies the major input data are necessary: 1 - the fluence distribution and the values of 3-loop and 4-loop RPV, 2 - RTNDT during the lifetime in operation, 3 - the temperature distribution values in the downcomer and the PTS evaluation. The main results must show significant margins against initiation of brittle fracture for all of 3-loop and 4-loop RPV. The flaws considered in this approach are shallow flaws beneath the cladding (subclad flaws) or in the first layer of cladding. The major tasks and expertises engaged by EDF are: • more precise assessment of the fluence calculations, • better knowledge of the vessel material properties, including the effect of radiation, • the NDE inspection program on the core zone. The comparison of the results are developed in this paper: • for the fluence evaluation and the optimisation of the fuel management, • the data gathered from radiation specimen capsules, removed from the vessels (radiation surveillance program), • and the thermal-hydraulic and mechanical calculations based on finite element thermal-hydraulic and 3D elastic-plastic mechanical computations.
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Bezdikian, G., Y. Rouillon, and J. Bourgoin. "French RPV Assessment — Contribution of Expertises in Mechanical Analyses." In ASME 2002 Pressure Vessels and Piping Conference. ASMEDC, 2002. http://dx.doi.org/10.1115/pvp2002-1351.
Анотація:
The process used by the French utility, concerning the Reactor Pressure Vessel assessment, applied on 54 PWR NPPs (3-loop and 4-loop Reactors), involves the verification of the integrity of the component by mechanical studies, in the most severe conditions of loading in relation with RTndt (Reference Nil Ductility Transition Temperature), and considering major parameters. This approach, is based on mechanical safety studies, to demonstrate the absence of risk of failure by brittle fracture. For these mechanical studies two major input data are necessary: 1 - the fluence distribution and the values during the lifetime in operation for each NPPs, 2 - the thermal-hydraulic evaluation and temperature distribution values in the downcomer. The main results must show significant margins against initiation of the brittle fracture. The flaws considered in this approach are shallow flaws beneath the cladding (subclad flaws) or in the first layer of cladding. The major tasks and expertises engaged by EDF are: • more precise assessment of the fluence and neutronic calculations, • better knowledge of the vessel material properties, including the effect of radiation, • the NDE inspection program based on the inspection of the vessel wall, with a special NDE tool to inspect the area in subcladding zone, • the evaluation of vessel integrity, the mechanical analysis of margins in major loading conditions. The principal actions conducted during recent years are: • the fuel management optimisation (low-leakage core design) and the new development to evaluate the fluence, • the data gathered from radiation specimen capsules, removed from the vessels (3 loop reactor), within the framework of the radiation surveillance program, and • the thermal-hydraulic-mechanical calculations based on finite element thermal-hydraulic computations and three dimensional elastic-plastic mechanical analyses.
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Gilles, Ph, J. P. Izard, and J. Devaux. "Application of the BEREMIN Model for Evidencing the Warm Pre-Stress Effect in an Irradiated Reactor Pressure Vessel Containing a Semi-Elliptical Subclad Defect Under Small and Large LOCA Conditions." In ASME 2008 Pressure Vessels and Piping Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/pvp2008-61809.
Анотація:
The nuclear power plants lifetime is strongly dependent of the guarantee of the reactor pressure vessel (RPV) integrity. Therefore, the RPV integrity has to be demonstrated under the most severe configuration, namely the Pressurized Thermal Shock induced by the Loss of Coolant Accident induced by a large break in the primary loop. For such a transient, the apparent risk of failure is maximum when the load is decreasing; the fracture resistance decreasing rate being stronger. However, such type of loading generates an increase of the fracture resistance as shown by numerous studies (Chell, 1980 – BEREMIN, 1981 – Smith et al., 2004). This is known as the warm pre-stress (WPS) effect. This beneficial effect on the resistance to brittle fracture is not accounted for in the French RCCM and RSEM codes (RCCM, 2000 – RSEM, 2005). EDF has launched several R&D actions with CEA and AREVA as well as with European partners (SMILE, 2001) to validate and model the WPS effect under RPV representative conditions. Proving the existence of this beneficial load history effect (designated as Warm Pre Stress WPS), in the case of a defective RPV in emergency and faulted conditions is the aim of the present paper. The demonstration is conducted in the case of cleavage fracture using an improved version of the BEREMIN model. As opposite to the classical Fracture Mechanics methodology, this approach allows to account for load history effects on cleavage. The study analyzes the behavior of a semi-elliptical under clad crack in the EoL core shell of a 900 MWe RPV for two loading cases: the large break Loss Of Coolant Accident transient and a small break LOCA inducing thermal fluctuations on the vessel inner wall. The WPS effect is evidenced by comparing the plasticity corrected SIF levels of two loadings for the same value of failure probability: the considered WPS loading and a virtual monotonously increasing load applied at the temperature at which the brittle fracture risk is estimated.
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Bezdikian, Georges, Franc¸oise Ternon-Morin, Henriette Churier-Bossennec, Dominique Moinereau, and Alain Martin. "French Four-Loop PWR 1300 MWe Reactor Pressure Vessel: First Results for Integrity Assessment and Life Manangement." In ASME 2003 Pressure Vessels and Piping Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/pvp2003-2152.
Анотація:
The process used by the French utility, concerning the Reactor Pressure Vessel (RPV) integrity assessment, applied on 34 PWR NPPs 3-loop Reactors, involved the verification of the integrity of the component under the most severe conditions of situation, was engaged several years ago and the result obtained was the justification of the 900 MWe RPV life management for at least 40 years and to prepare the projection for beyond 40 years. Since 2000, in the continuity of this results, the studies was carried out on the 20 PWR NPPs 4-loop 1300 MWe Reactor Pressure Vessels, and the recent results obtained shows the demonstration of the integrity of the RPV, in the most severe conditions of loading in relation with RTNDT (Reference Nil Ductility Transition Temperature), and considering major parameters particularly the severity of the transient. This approach, is based on specific mechanical safety studies on the 1300 MWe RPV, to demonstrate the absence of risk of failure by brittle fracture. For these mechanical studies the major input data are necessary: 1 - the fluence distribution and the values of 4-loop RPV RTNDT during the lifetime in operation, 2 - the temperature distribution values in the downcomer and the PTS evaluation. The main results must show significant margins against initiation of the brittle fracture. The flaws considered in this approach are shallow flaws beneath the cladding (subclad flaws) or in the first layer of cladding. The major tasks and expertises engaged by EDF are: • better knowledge of the vessel material properties, including the effect of radiation, • more precise assessment of the fluence and neutronic calculations, • the NDE inspection program based on the inspection of the vessel wall, with a special NDE tool. The principal actions conducted during recent years are: • the optimisation of the fuel management and the new development for the fluence evaluation, • the data gathered from radiation specimen capsules, removed from the vessels (4loop reactor), within the framework of the radiation surveillance program, and the thermal-hydraulic-mechanical calculations based on finite element thermal-hydraulic computations and three dimensional elastic-plastic mechanical analyses.