Letteratura scientifica selezionata sul tema "Modular PKS engineering"
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Articoli di riviste sul tema "Modular PKS engineering":
1
Beck, Charlotte, Jaime Felipe Guerrero Garzón e Tilmann Weber. "Recent Advances in Re-engineering Modular PKS and NRPS Assembly Lines". Biotechnology and Bioprocess Engineering 25, n. 6 (dicembre 2020): 886–94. http://dx.doi.org/10.1007/s12257-020-0265-5.
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Wesener, Shane R., Vishwakanth Y. Potharla e Yi-Qiang Cheng. "Reconstitution of the FK228 Biosynthetic Pathway Reveals Cross Talk between Modular Polyketide Synthases and Fatty Acid Synthase". Applied and Environmental Microbiology 77, n. 4 (23 dicembre 2010): 1501–7. http://dx.doi.org/10.1128/aem.01513-10.
Abstract (sommario):
ABSTRACTFunctional cross talk between fatty acid biosynthesis and secondary metabolism has been discovered in several cases in microorganisms; none of them, however, involves a modular biosynthetic enzyme. Previously, we reported a hybrid modular nonribosomal peptide synthetase (NRPS)-polyketide synthase (PKS) pathway for the biosynthesis of FK228 anticancer depsipeptide inChromobacterium violaceumstrain 968. This pathway contains two PKS modules on the DepBC enzymes that lack a functional acyltransferase (AT) domain, and no apparent AT-encoding gene exists within the gene cluster or its vicinity. We report here that, through reconstitution of the FK228 biosynthetic pathway inEscherichia colicells, two essential genes,fabD1andfabD2, both encoding a putative malonyl coenzyme A (CoA) acyltransferase component of the fatty acid synthase complex, are positively identified to be involved in FK228 biosynthesis. Either gene product appears sufficient to complement the AT-less PKS modules on DepBC for polyketide chain elongation. Concurrently, a gene (sfp) encoding a putative Sfp-type phosphopantetheinyltransferase was identified to be necessary for FK228 biosynthesis as well. Most interestingly, engineeredE. colistrains carrying variable genetic components produced significant levels of FK228 under both aerobic and anaerobic cultivation conditions. Discovery of thetranscomplementation of modular PKSs by housekeeping ATs reveals natural product biosynthesis diversity. Moreover, demonstration of anaerobic production of FK228 by an engineered facultative bacterial strain validates our effort toward the engineering of novel tumor-targeting bioagents.
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Musiol-Kroll, Ewa, e Wolfgang Wohlleben. "Acyltransferases as Tools for Polyketide Synthase Engineering". Antibiotics 7, n. 3 (18 luglio 2018): 62. http://dx.doi.org/10.3390/antibiotics7030062.
Abstract (sommario):
Polyketides belong to the most valuable natural products, including diverse bioactive compounds, such as antibiotics, anticancer drugs, antifungal agents, immunosuppressants and others. Their structures are assembled by polyketide synthases (PKSs). Modular PKSs are composed of modules, which involve sets of domains catalysing the stepwise polyketide biosynthesis. The acyltransferase (AT) domains and their “partners”, the acyl carrier proteins (ACPs), thereby play an essential role. The AT loads the building blocks onto the “substrate acceptor”, the ACP. Thus, the AT dictates which building blocks are incorporated into the polyketide structure. The precursor- and occasionally the ACP-specificity of the ATs differ across the polyketide pathways and therefore, the ATs contribute to the structural diversity within this group of complex natural products. Those features make the AT enzymes one of the most promising tools for manipulation of polyketide assembly lines and generation of new polyketide compounds. However, the AT-based PKS engineering is still not straightforward and thus, rational design of functional PKSs requires detailed understanding of the complex machineries. This review summarizes the attempts of PKS engineering by exploiting the AT attributes for the modification of polyketide structures. The article includes 253 references and covers the most relevant literature published until May 2018.
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Rascher, Andreas, Zhihao Hu, Greg O. Buchanan, Ralph Reid e C. Richard Hutchinson. "Insights into the Biosynthesis of the Benzoquinone Ansamycins Geldanamycin and Herbimycin, Obtained by Gene Sequencing and Disruption". Applied and Environmental Microbiology 71, n. 8 (agosto 2005): 4862–71. http://dx.doi.org/10.1128/aem.71.8.4862-4871.2005.
Abstract (sommario):
ABSTRACT Geldanamycin and the closely related herbimycins A, B, and C were the first benzoquinone ansamycins to be extensively studied for their antitumor properties as small-molecule inhibitors of the Hsp90 protein chaperone complex. These compounds are produced by two different Streptomyces hygroscopicus strains and have the same modular polyketide synthase (PKS)-derived carbon skeleton but different substitution patterns at C-11, C-15, and C-17. To set the stage for structural modification by genetic engineering, we previously identified the gene cluster responsible for geldanamycin biosynthesis. We have now cloned and sequenced a 115-kb segment of the herbimycin biosynthetic gene cluster from S. hygroscopicus AM 3672, including the genes for the PKS and most of the post-PKS tailoring enzymes. The similarities and differences between the gene clusters and biosynthetic pathways for these closely related ansamycins are interpreted with support from the results of gene inactivation experiments. In addition, the organization and functions of genes involved in the biosynthesis of the 3-amino-5-hydroxybenzoic acid (AHBA) starter unit and the post-PKS modifications of progeldanamycin were assessed by inactivating the subclusters of AHBA biosynthetic genes and two oxygenase genes (gdmM and gdmL) that were proposed to be involved in formation of the geldanamycin benzoquinoid system. A resulting novel geldanamycin analog, KOS-1806, was isolated and characterized.
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He, Yunlong, Yuhui Sun, Tiangang Liu, Xiufen Zhou, Linquan Bai e Zixin Deng. "Cloning of Separate Meilingmycin Biosynthesis Gene Clusters by Use of Acyltransferase-Ketoreductase Didomain PCR Amplification". Applied and Environmental Microbiology 76, n. 10 (26 marzo 2010): 3283–92. http://dx.doi.org/10.1128/aem.02262-09.
Abstract (sommario):
ABSTRACT Five meilingmycins, A to E, with A as the major component, were isolated from Streptomyces nanchangensis NS3226. Through nuclear magnetic resonance (NMR) characterization, meilingmycins A to E proved to be identical to reported milbemycins α11, α13, α14, β1, and β9, respectively. Sequencing of a previously cloned 103-kb region identified three modular type I polyketide synthase genes putatively encoding the last 11 elongation steps, three modification proteins, and one transcriptional regulatory protein for meilingmycin biosynthesis. However, the expected loading module and the first two elongation modules were missing. In meilingmycin, the presence of a methyl group at C-24 and a hydroxyl group at C-25 suggests that the elongation module 1 contains a methylmalonyl-coenzyme A (CoA)-specific acyltransferase (ATp) domain and a ketoreductase (KR) domain. Based on the conserved motifs of the ATp and KR domains, a pair of primers was designed for PCR amplification, and a 1.40-kb expected fragment was amplified, whose sequence shows significant homology with the elongation module 1 of the aveA1-encoded enzyme AVES1. A polyketide synthase (PKS) gene encoding one loading and two elongation modules, with a downstream C-5-O-methyltransferase gene, meiD, was subsequently localized 55 kb apart from the previously sequenced region, and its deletion abolishes meilingmycin production. A series of deletions within the 55-kb intercluster region rules out its involvement in meilingmycin biosynthesis. Furthermore, gene deletion of meiD eliminates meilingmycins D and E, with methyls at C-5. Our work provides a more specific strategy for the cloning of modular type I PKS gene clusters. The cloning of the meilingmycin gene clusters paves the way for its pathway engineering.
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Haydock, Stephen F., Anthony N. Appleyard, Tatiana Mironenko, John Lester, Natasha Scott e Peter F. Leadlay. "Organization of the biosynthetic gene cluster for the macrolide concanamycin A in Streptomyces neyagawaensis ATCC 27449". Microbiology 151, n. 10 (1 ottobre 2005): 3161–69. http://dx.doi.org/10.1099/mic.0.28194-0.
Abstract (sommario):
The macrolide antibiotic concanamycin A has been identified as an exceptionally potent inhibitor of the vacuolar (V-type) ATPase. Such compounds have been mooted as the basis of a potential drug treatment for osteoporosis, since the V-ATPase is involved in the osteoclast-mediated bone resorption that underlies this common condition. To enable combinatorial engineering of altered concanamycins, the biosynthetic gene cluster governing the biosynthesis of concanamycin A has been cloned from Streptomyces neyagawaensis and shown to span a region of over 100 kbp of contiguous DNA. An efficient transformation system has been developed for S. neyagawaensis and used to demonstrate the role of the cloned locus in the formation of concanamycin A. Sequence analysis of the 28 ORFs in the region has revealed key features of the biosynthetic pathway, in particular the biosynthetic origin of portions of the backbone, which arise from the unusual polyketide building blocks ethylmalonyl-CoA and methoxymalonyl-ACP, and the origin of the pendant deoxysugar moiety 4′-O-carbamoyl-2′-deoxyrhamnose, as well as the presence of a modular polyketide synthase (PKS) encoded by six giant ORFs. Examination of the methoxymalonyl-specific acyltransferase (AT) domains has led to recognition of an amino acid sequence motif which can be used to distinguish methylmalonyl-CoA- from methoxymalonyl-ACP-specific AT domains in natural PKSs.
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Agergaard, Julie Krogh, Kristoffer Wernblad Sigsgaard, Niels Henrik Mortensen, Simon Didriksen, Kasper Barslund Hansen e Jingrui Ge. "MODULAR MAINTENANCE DECISION ARCHITECTURE". Proceedings of the Design Society 3 (19 giugno 2023): 2715–24. http://dx.doi.org/10.1017/pds.2023.272.
Abstract (sommario):
AbstractThe operation of large production assets requires many decisions from the acquisition and design of new assets to the choice of lubricant for a specific piece of equipment. The decisions made in maintenance have a direct effect on the management of the production process, making it important to ensure correct maintenance decision making. However, studies on maintenance decision making tend to focus on smaller areas of decisions being made in a process, but rarely the entire process. To introduce more studies that consider the entire maintenance process, this paper proposes using a modular Maintenance Decision Architecture. The paper introduces a framework for structuring information sources into standardized information modules and mapping them to maintenance decisions made across the entire organization. The application of approaches from product, system, and service engineering are used to support the management of the complexities of maintenance of large production facilities.
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Wang, Guimei, Lijie Yang e Yong Shuo Zhang. "Modularized design of coal-mine paste filling station based on fuzzy theory". World Journal of Engineering 15, n. 6 (3 dicembre 2018): 743–50. http://dx.doi.org/10.1108/wje-01-2018-0006.
Abstract (sommario):
Purpose This paper aims to study a modular method for designing a paste filling station (PFS) for a coal mine (CM) to reduce the PFS’s input cost and achieve reutilization. Design/methodology/approach Modular design criteria for the PFS are proposed and a modular division (MDiv) model and an evaluation method are established. The correlation-strength matrix of the PFS parts expressed in the form of rough numbers is transformed into a fuzzy equivalent matrix. The theory of rough sets and the fuzzy clustering method are introduced for PFS MDiv. The evaluating method is established for the PFS MDiv scheme based on the principle of fuzzy comprehensive evaluation. Findings Taking a particular CM PFS as an example, the above method is used to modularize the PFS, and the optimal division of the PFS is finally determined via the above evaluation system. Applying this method solves the problem of high cost investment in the initial stage of PFS construction. Originality/value The theory of rough sets and the fuzzy clustering method are introduced for PFS MDiv. An evaluating method is established for the PFS MDiv scheme based on the principle of fuzzy comprehensive evaluation, thereby providing new ideas for PFS transformation and reutilization.
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Rana, Vighneshkumar, e Vishal Singh. "Analyzing the dimensional aspects of 3D volumetric spaces: a product-oriented perspective". Proceedings of the Design Society 4 (maggio 2024): 2433–42. http://dx.doi.org/10.1017/pds.2024.246.
Abstract (sommario):
AbstractThe concept of volumetric spaces has evolved in the Architecture, Engineering, and Construction (AEC) sector, ranging from traditional onsite built spaces to modern modular houses and portable architecture. Despite this diversity, there lacks a comprehensive framework to analyze volumetric space products across dimensions. This paper presents a conceptual framework based on abductive reasoning and qualitative analysis, aiming to explore interdependencies among dimensions. It hypothesizes that volumetric space dimensions are perceived differently and demonstrate interdependencies.
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Breimann, Richard, Christoph Rennpferdt, Sven Wehrend, Eckhard Kirchner e Dieter Krause. "EXPLOITING THE SUSTAINABILITY POTENTIAL OF MODULAR PRODUCTS BY INTEGRATING R-IMPERATIVES INTO PRODUCT LIFE PHASES". Proceedings of the Design Society 3 (19 giugno 2023): 1785–94. http://dx.doi.org/10.1017/pds.2023.179.
Abstract (sommario):
AbstractClimate change and the growing consumption of natural resources has made it increasingly clear that engineering must focus on the development of more sustainable products. To do so, the methodologies for developing products need to address sustainability. However, many of the frequently used methodologies, such as Modular Function Deployment (MFD) or the Life Phases Modularisation (LPM), do not do that sufficiently. The product life phases, these methodologies are based, only address sustainability in the form of recycling. That is why a broader approach to sustainability, such as the R-imperatives, is not considered. Therefore, in this contribution, the model of product life phases is extended by integrating the R-imperatives. Furthermore, the module drivers resulting from the extended product life phases that are necessary to apply the MFD and the LPM are developed. Finally, the positive impact of the developed module drivers on the product architecture is shown by applying the resulting method onto an industrial example.
Tesi sul tema "Modular PKS engineering":
1
Su, Li. "Generation of analogues of the anti-tumor polyketide stambomycins by genetic engineering and allied approaches". Electronic Thesis or Diss., Université de Lorraine, 2021. http://www.theses.fr/2021LORR0081.
Abstract (sommario):
Les polycétides d’origine bactérienne sont une source importante de molécules anti-infectieuses et anticancéreuses d’origine naturelle utilisées en thérapie. Cependant, leurs structures doivent souvent être optimisées afin d'améliorer leurs propriétés thérapeutiques. Les stambomycines, une famille de macrolides parmi les plus grands polycétides connus (elles possèdent un noyau macrolactone à 51 membres), ont été récemment découvertes par une approche de genome mining chez la bactérie Streptomyces ambofaciens ATCC23877. Ces molécules présentent une activité anticancéreuse prometteuse. Six formes de stambomycines ont été caractérisées. Elles diffèrent les unes des autres par la fonctionnalité alkyle au niveau de la position C-26 du noyau macrolactone. Cette variabilité est due au choix alternatif d’unités d'extension par un domaine acyltransférase exceptionnel, le domaine AT12, de la polycétide synthase modulaire (PKS) responsable de la synthèse des stambomycines. Étant donné la taille importante du cycle lactone et la promiscuité intrinsèque du domaine AT12, il existe un intérêt substantiel à accéder à des dérivés stambomycines par réduction de la taille du noyau ou par substitution de la chaine latérale en C-26. Ces dérivés pourraient conserver la bioactivité des structures parentales ou présenter des propriétés améliorées voire nouvelles. Dans ce travail, nous avons mis à profit notre compréhension actuelle des systèmes de PKS modulaires pour raccourcir en interne la chaîne de production de stambomycines, ce qui a permis de générer avec succès, bien qu'à faible rendement, des dérivés avec un noyau macrolactone de taille réduite (des "mini-stambomycines" présentant un noyau à 37 membres). Grâce à une analyse minutieuse, nous avons pu identifier les multiples facteurs expliquant les faibles rendements, ce qui permettra d’éclairer les futures stratégies d'ingénierie. En outre, grâce à une stratégie de mutasynthèse, nous avons pu exploiter la large spécificité du domaine AT12 pour générer six nouveaux analogues de stambomycine présentant différentes substitutions en position C-26. Enfin, nous avons identifié de manière tout à fait inattendue trois classes de sidérophores étroitement apparentées aux desferrioxamines produites par S. ambofaciens. Un certain nombre des métabolites clés générés pendant ce travail constitue une source de nouvelles biomolécules avec des applications thérapeutiques potentielles. Les prochaines étapes consisteront à purifier ces composés, à déterminer leur structure puis à évaluer leurs activités biologiquesThe polyketide secondary metabolites of bacteria are a rich source of bioactive agents, with notable applications in anti-infective and anti-cancer therapy. However, their structures often need to be optimized in order to tailor their therapeutic and biophysical properties. The 51-membered macrolide stambomycins, among the largest of known polyketides, were recently discovered by genome mining in Streptomyces ambofaciens ATCC23877, and notably exhibit promising anti-cancer activity. The family encompasses six members which differ from each other in the alkyl functionality at C-26, due to the alternative choice of extender units by an exceptional acyl transferase domain (AT12) of the modular polyketide synthase (PKS) responsible for synthesizing the stambomycin core. Given their enormous size of the stambomycins and the intrinsic promiscuity of AT12, there is substantial interest in accessing ring-contracted and C-26 substituted derivatives of this compounds which might retain the bioactivity of the parental structures, or exhibit improved or even new properties. In this work, we have leveraged our current understanding of modular PKS systems to internally contract the stambomycin assembly line, leading to the successful generation, albeit at low yield, of target smaller derivatives (37-membered ‘mini-stambomycins’). By careful analysis, we could identify multiple factors contributing to the low titers, information which should inform future engineering strategies. Furthermore, using a mutasynthesis strategy, we were able to exploit the broad specificity of the AT12 domain to create 6 novel C-26 substituted stambomycin analogues. Finally, we unexpectedly identified three series of novel desferrioxamine siderophores produced by S. ambofaciens. As a number of key metabolites generated in this work have potential interest for therapeutic applications, they will be targeted for purification, structural characterization and biological evaluation
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Zarzoso, Vicente. "Traitement aveugle et semi-aveugle du signal pour les télécommunications et le génie biomédical". Habilitation à diriger des recherches, Université de Nice Sophia-Antipolis, 2009. http://tel.archives-ouvertes.fr/tel-00486872.
Abstract (sommario):
Ce rapport résume mes activités de recherche depuis l'obtention de mon doctorat. Je me suis penché sur le problème fondamental de l'estimation de signaux sources à partir de l'observation de mesures corrompues de ces signaux, dans des scénarios où les données mesurées peuvent être considérées comme une transformation linéaire inconnue des sources. Deux problèmes classiques de ce type sont la déconvolution ou égalisation de canaux introduisant des distorsions linéaires, et la séparation de sources dans des mélanges linéaires. L'approche dite aveugle essaie d'exploiter un moindre nombre d'hypothèses sur le problème à résoudre : celles-ci se réduisent typiquement à l'indépendance statistique des sources et l'inversibilité du canal ou de la matrice de mélange caractérisant le milieu de propagation. Malgré les avantages qui ont suscité l'intérêt pour ces techniques depuis les années soixante-dix, les critères aveugles présentent aussi quelques inconvénients importants, tels que l'existence d'ambiguïtés dans l'estimation, la présence d'extrema locaux associés à des solutions parasites, et un coût de calcul élevé souvent lié à une convergence lente. Ma recherche s'est consacrée à la conception de nouvelles techniques d'estimation de signal visant à pallier aux inconvénients de l'approche aveugle et donc à améliorer ses performances. Une attention particulière a été portée sur deux applications dans les télécommunications et le génie biomédical : l'égalisation et la séparation de sources dans des canaux de communications numériques, et l'extraction de l'activité auriculaire à partir des enregistrements de surface chez les patients souffrant de fibrillation auriculaire. La plupart des techniques proposées peuvent être considérées comme étant semi-aveugles, dans le sens où elles visent à exploiter des informations a priori sur le problème étudié autres que l'indépendance des sources ; par exemple, l'existence de symboles pilotes dans les systèmes de communications ou des propriétés spécifiques de la source atriale dans la fibrillation auriculaire. Dans les télécommunications, les approches que j'ai explorées incluent des solutions algébriques aux fonctions de contraste basées sur la modulation numérique, la combinaison de contrastes aveugles et supervisés dans des critères semi-aveugles, et une technique d'optimisation itérative basée sur un pas d'adaptation calculé algébriquement. Nos efforts visant à extraire le signal atrial dans des enregistrements de fibrillation auriculaire nous ont permis non seulement de dégager de nouvelles fonctions de contraste basées sur les statistiques de second ordre et d'ordre élevé incorporant l'information a priori sur les statistiques des sources, mais aussi d'aboutir à de nouveaux résultats d'impact clinique et physiologique sur ce trouble cardiaque encore mal compris. Ce rapport se conclut en proposant quelques perspectives pour la continuation de ces travaux. Ces recherches ont été menées en collaboration avec un nombre de collègues en France et à l'étranger, et ont également compris le co-encadrement de plusieurs doctorants. Les contributions qui en ont découlé ont donné lieu à plus de soixante publications dans des journaux, des conférences et des ouvrages collectifs à caractère international. Quelques-unes de ces publications sont jointes à ce document.
Capitoli di libri sul tema "Modular PKS engineering":
1
JianBing, Chen. "PEEK and PES ☆". In Reference Module in Materials Science and Materials Engineering. Elsevier, 2018. http://dx.doi.org/10.1016/b978-0-12-803581-8.02607-2.
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Glinsky, Albert. "A Eunuch in a Harem". In Switched On, 80—C8.P38. Oxford University PressNew York, 2022. http://dx.doi.org/10.1093/oso/9780197642078.003.0008.
Abstract (sommario):
Abstract The Abominatron was an unexpected hit at the 1964 Audio Engineering Society (AES) convention, attracting the attention of luminaries and musical heavy-hitters such as Alwin Nikolais, Eric Siday, Lejaren Hiller, and people from the Columbia-Princeton Electronic Music Center. Bob found himself taking orders for modules, something he’d never anticipated. Nikolais and Siday become his first customers. But in the meantime, he needed to roll out the high-end amp (dubbed the PMS-15) because the business had lost $28,000. Tooling up to produce 100, he ended up selling three—a catastrophic end to a two-year project. But success at AES gave him hope and he threw himself into hawking the new equipment, taking an ad in a 1965 AES journal, and attending the Music Teacher’s National Association (MTNA) convention. No sales were secured at the convention, but Bob met George Kelischek, an instrument builder who would become very influential in his life.
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Subirats, X., E. Fuguet, M. Rosés, E. Bosch e C. Ràfols. "Methods for pKa Determination (I): Potentiometry, Spectrophotometry, and Capillary Electrophoresis". In Reference Module in Chemistry, Molecular Sciences and Chemical Engineering. Elsevier, 2015. http://dx.doi.org/10.1016/b978-0-12-409547-2.11559-8.
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Qin, Weijin, Ya Liu e Xuhai Yang. "Performance Analysis on a Traceable Precise Satellite Timing". In Advances in Transdisciplinary Engineering. IOS Press, 2022. http://dx.doi.org/10.3233/atde221204.
Abstract (sommario):
Polluted by the noise of the observation, precision of satellite timing based on pseudoranges can merely reach tens of nanoseconds. Considering the sharply increasing demand of high-precision timing in the many fields, a traceable precise timing system has been proposed, which means having a connection with UTC (Coordinated Universal Time). We introduce the principle of the PPP (Precise Point Positioning) timing system and conduct the experiment with the form of zero baseline, long baseline, and very long baseline, simultaneously, CV (Common View) and AV (All in View) timing solution are used for comparison. Finally, the system performance has been evaluated from the aspects of precision and stability. The results show, when the Rubidium module is the frequency source of the user terminal, the 1 PPS timing accuracy of 904 km achieved by this method is 0.32 ns, and the frequency stability can achieve about 9.51e-13, 5.58e-13 and 1.37e-13 at the averaging time of 100 s, 1000 s and 10000 s. The timing bias is approximate 2 ns. Besides, the variation of the temperature will affect the timing results. Compared to the pseudorange timing solution, improvement on the PPP short term stability is more obvious than that of long term stability.
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Fuguet, E., X. Subirats, C. Ràfols, E. Bosch e M. Rosés. "Methods for pKa Determination (II): Sparingly Soluble Compounds and High-Throughput Approaches". In Reference Module in Chemistry, Molecular Sciences and Chemical Engineering. Elsevier, 2015. http://dx.doi.org/10.1016/b978-0-12-409547-2.11631-2.
Atti di convegni sul tema "Modular PKS engineering":
1
Zhang, Dan, Lihui Wang e Sherman Y. T. Lang. "Modelling and Control of PKM in an Integrated Environment". In ASME 2003 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/detc2003/cie-48178.
Abstract (sommario):
This paper introduces an integrated validation system that consists of the following modular components: kinematic/dynamic analysis module, kinetostatic model, CAD module, FEM module, CAM module, optimization module and visual environment for remote control. In this paper, authors focus mainly on the modules of kinetostatic modeling, dynamic modeling, PKM design optimization, and remote control realization. The prototype of a 3-dof PKM developed at NRC-IMTI is used as an example throughout this paper.
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Kitzmiller, John T., Richard G. Anderson, Laura L. Genutis e Dennis M. Popp. "Effects on Core Damage Frequency to Sensitivity of Instrumentation and Control Reliability". In 17th International Conference on Nuclear Engineering. ASMEDC, 2009. http://dx.doi.org/10.1115/icone17-75413.
Abstract (sommario):
Core Damage Frequency (CDF) and Large Release Frequency (LRF) can be greatly affected by the application of Instrumentation and Control (I&C) within the control and safety systems utilized in the operations of a nuclear power plant. It is important that the modeling of these systems be an accurate representation of the I&C design to capture the effects of the I&C on the operations of the nuclear power plant as far as control and safety that are needed for the effective and safe operation of power generation. Various sensitivities can be performed on I&C modeling in the AP1000 Probabilistic Risk Assessment (PRA) to determine the impact on CDF. These sensitivities can be in the areas of base reliability values (probabilities), common cause failures (CCF) of software as well as common cause (CC) factors of computer modules. Insights can be found as to the effects of these CCFs by varying the modeled probabilities in the most conservative direction to determine how the model will respond. The model response, i.e., CDF and cutset importance orders will provide insights as to how sensitive I&C modeling is to CCF and how sensitive the rest of the PRA model is to I&C. Increasing failure probability of the Protection and Safety Monitoring System (PMS) and Plant Control System (PLS), and Diverse Actuation System (DAS) to explore the minimum reliability that would support favorable CDF and LRF values, as well as, the effect of total failure of the PMS (no credit taken for PMS in core damage sequences) and PLS (no credit taken for PLS in core damage sequences) on CDF values are explored. Sensitivity analyses show that the CDF increases if no credit is taken for operator actions. For AP1000, this sensitivity study indicated a decrease in dependence on operator actions over conventional nuclear plants. This conclusion is likely a result of the increased reliability of the PMS to automatically actuate the given systems and components. For this reason, the most important system is PMS, in the case where no credit is taken for PMS in core damage sequences.
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Han, Changwan, Seonghun Park e Hanjong Kim. "Dynamic Response of Polyvinyl Alcohol(PVA)-Hydrogel With Different PVA Concentrations". In ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-37811.
Abstract (sommario):
Polyvinyl Alcohol-Hydrogel (PVA-H) is a biomaterial used for manufacturing contact lenses as well as for the medium of drug delivery. Previous studies have also showed that PVA-H exhibits superior biocompatibility with hydrophilic elastic nature. The aim of this study is to examine the possible usage of the PVA-H as cartilage replacement material by determining the static and dynamic mechanical properties of PVA-H with different ratios of polyvinyl alcohol (PVA) and phosphate buffered saline (PBS) compositions. Three different types of PVA-H specimens were made by changing the ratio of PVA (Sigma-Aldrich) and PBS (Sigma-Aldrich) compositions (PVA-H1: 10 wt% PVA and 90 wt% PBS; PVA-H2: 20 wt% PVA and 80 wt% PBS; PVA-H3: 25 wt% PVA, 45 wt% PBS and DMSO 30 wt%). Static and dynamic tensile tests under the loading frequencies of 0.001, 0.01, 0.1, and 1 Hz were carried out to measure the biomechanical properties of PVA-H1, -H2 within PBS solution and -H3 within PBS/ DMSO solution. The equilibrium Young’s moduli (EY) of PVA-H1, -H2 and -H3 evaluated from the static displacement control were 84.2±35.1 kPa (n=10), 254±32.2 kPa (n=10) and 588±38.9 kPa (n=5), respectively. The amplitudes of dynamic tensile moduli were varied from 86.3±33.4 kPa (n=10) at 0.001 Hz to 96.9±42.0 kPa (n=10) at 1 Hz for PVA-H1, from 282.7±26.4 kPa (n=10) at 0.001 Hz to 309.1±32.2 kPa (n=10) at 1 Hz for PVA-H2 and from 643.8±49.8 kPa (n=10) at 0.001 Hz to 747.7±67.7 kPa (n=5) at 1 Hz for PVA-H3. According to the current results, the frequency dependence of the magnitude of the dynamic modulus confirms the viscoelastic nature of PVA-H material. However, it can be noted that the dynamic modulus increases by up to a factor of 1.15 for PVA-H1, 1.22 for PVA-H2 and 1.27 for PVA-H3, showing insignificant viscoelasticity compared with that for cartilage. The result that static and dynamic moduli of PVA-H3 are larger than those of PVA-H1 and PVA-H2 also suggests that the amount of PVA composition in PVA-H plays an important role in improving both static and dynamic mechanical strengths of PVA-H material. The phase angle decreased from 5.2±2.1 ° at 0.001 Hz to −0.3±1.7 ° at 1 Hz for PVA-H1, from 5.6±0.6 ° at 0.001 Hz to −0.3±0.7 ° at 1 Hz for PVA-H2 and from 8.2±1.1 ° at 0.001 Hz to 0.7±0.7 ° at 1 Hz for PVA-H3.
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Eilmus, Sandra, e Dieter Krause. "Product Life-Oriented Development of Component Commonality and Variety". In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-63619.
Abstract (sommario):
To reach many customers and have a broad range of products at marketable prices companies aim for high commonality across product variants. Commonality is known as the sharing of components by product variants. But using the same components for different product variants can also lead to trade-offs in product function and fulfillment of customer requirements as well as in internal processes. The aim of this paper is to investigate by literature review and a case study on forklift trucks how benefits and trade-offs can be balanced according to corporate needs. Existing tools from the Integrated PKT-Approach for Developing Modular Product Families are applied and advanced in the case study. Practical examples demonstrate that commonality is a gradual property that can be given to variant components as well and that it is influenced by the modular structure and how components are handled as modules in different life phases. New product concepts with enhanced commonality are derived and evaluated by estimating the created lot size caused and code number caused costs.
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Müller, Andreas. "A Lie Group Approach to the Modular Modeling of Kinematically Non-Redundant Parallel Mechanisms". In ASME 2019 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/detc2019-98283.
Abstract (sommario):
Abstract Parallel kinematics manupulators (PKM) are established robotic systems. Yet there is no established modeling approach that takes into account the special kinematics of the (usually structurally identical) limbs. In this paper a modeling approach is proposed that accounts for the special kinematics and topology of PKM. It makes use of modern Lie group formulations for rigid body systems that admits efficient description independent of modeling conventions. A task space formulation is presented that can be directly used for model-based control purposes.
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Zhang, Dan, Lihui Wang e Sherman Y. T. Lang. "An Integrated Virtual Validation System for Parallel Kinematic Machine Analysis Design". In ASME 2003 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/detc2003/dac-48825.
Abstract (sommario):
Selecting a configuration for a machine tool that will best suit the needs of a forecast set of requirements can be a difficulty and costly exercise. This problem can now be addressed using an integrated virtual validation system. The system includes kinematic/dynamic analysis, kinetostatic model, CAD module, FEM module, CAM module, optimization module and visual environment for simulation and collision detection of the machining and deburring. It is an integration of the parallel kinematic machines (PKM) design, analysis, optimization and simulation. In this paper, the integrated virtual system is described in a detail, a prototype of a 3-dof PKM is modeled, analyzed, optimized and remote controlled with the proposed system. Some results and simulations are also given. Its effectiveness is shown with the results obtained by NRC-IMTI during the design of the 3-dof NRC PKM.
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Chen, Hui, e Zhixing Wang. "Computer Aided Manufacturing of Marine Propellers by Parallel Kinematics Machine". In ASME 2003 International Mechanical Engineering Congress and Exposition. ASMEDC, 2003. http://dx.doi.org/10.1115/imece2003-41727.
Abstract (sommario):
Techniques of manufacturing integral marine propellers by Parallel Kinematics Machine (PKM) are discussed in this paper, and complete CAD/CAM steps for manufacturing propellers using UG CAD/CAM system are presented. The designed propeller model is defined by a series of aerofoil sections data, so UG/CAD module are used to create the 3-dimensional model of propeller, and tool paths are generated in UG/CAM module. Vericut is adopted to simulate the tool paths generated by UG/CAM and to check interferences. NC postprocessor for PKM is developed on the basis of UG/Post. It is invoked in UG/CAM and converts tool path data into NC program to drive PKM. Finally, machining experiments based on all the techniques discussed in this paper are made. Not only does it puts forward a new scheme and machine to manufacture marine propellers, but also can push the industrialization and practicality of PKM.
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Pradhan, A. K., A. Routray e A. Behera. "Power quality disturbance classification employing modular wavelet network". In 2006 IEEE Power Engineering Society General Meeting. IEEE, 2006. http://dx.doi.org/10.1109/pes.2006.1709452.
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Wehlin, Camilla, Olle Vidner, Leon Poot e Mehdi Tarkian. "Integrating Sales, Design and Production: A Configuration System for Automation in Mass Customization". In ASME 2021 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/detc2021-68426.
Abstract (sommario):
Abstract Companies manufacturing customized engineer-to-order (ETO) products are decelerated by repetitive work, misinterpretations and uncoordinated processes which prohibits the achievement of mass customization. Being able to deliver customized product with low costs and fast delivery times, the concept of mass customization, is a prerequisite for maintained competitiveness with the demands from the market today. This paper presents a product configuration system (PCS) for customized products using design automation enabled by knowledge-based engineering (KBE) and enterprise-wide optimization (EWO). With this approach, the process from sales to delivery of customized products can be extensively rationalized. The PCS consists of two modules. The first being a configurator for use in the sales quotation stage. Here, customer requirements are captured, and used to generate alternatives feasible for the customer context. Thereby, correct quotations can be generated at the sales instance. The second module is the enterprise-wide configurator where accepted orders are concurrently optimized for their detailed and final design, considering the current state of the production and concurrent sales cases in the company. In other terms, instead of adapting the supply chain according to the design of the products in the order entry, the design of the products in the order entry are adapted according to the state of the supply chain. Thereby, resources can be efficiently utilized to the benefit of both the customer and the company, with reduced costs and delivery times. An implementation of the PCS in a case concerning spiral staircases, an ETO product, has shown potential of substantially reducing resources and errors and enable a reliable process supporting achievement of mass customization.
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Yu, Mingrui, Hongliang Wang, Zhuo Liu, Yu Feng, Xu Han e Yidan Yuan. "Experimental Research on Drag Characteristic of Air Flow Path for ACP-100 Passive Containment Air Cooling System". In 2022 29th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/icone29-91504.
Abstract (sommario):
Abstract Passive containment air cooling system (PAS) is an important special safety system for the small modular pressurized water reactor ACP-100. The heat is transferred to the environment by the natural draft air cooling under accident conditions. The flow loss of the air flow paths has an important influence on the heat transfer power of PAS. A one-sixth scale model of PAS air flow path was constructed which was a 90° wedge angle sector of the cylindrical symmetric passages. The pressure distributions at different sections of the model were measured, the drag coefficients were analyzed. The experimental results showed that the total drag coefficients of the four different air inlet paths were almost the same, and they showed a decreasing trend with the increase of Reynolds number. The sleeves had the largest drag coefficient, accounting for about 26%, followed by the air inlet, chimney outlet, the turning and the corridor. The other components had little effect on the pressure loss. Afterward, the aerodynamic modification was carried out, the modification for the turning could reduce the total drag coefficient by 4.5 %. The experimental results of this paper provide necessary data support for the ACP 100 engineering design.