Littérature scientifique sur le sujet « 2-crossed module »
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Articles de revues sur le sujet "2-crossed module"
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JURČO, BRANISLAV. « NONABELIAN BUNDLE 2-GERBES ». International Journal of Geometric Methods in Modern Physics 08, no 01 (février 2011) : 49–78. http://dx.doi.org/10.1142/s0219887811004963.
Texte intégralRésumé :
We define 2-crossed module bundle 2-gerbes related to general Lie 2-crossed modules and discuss their properties. If (L → M → N) is a Lie 2-crossed module and Y → X is a surjective submersion then an (L → M → N)-bundle 2-gerbe over X is defined in terms of a so-called (L → M → N)-bundle gerbe over the fiber product Y[2] = Y × XY, which is an (L → M)-bundle gerbe over Y[2] equipped with a trivialization under the change of its structure crossed module from L → M to 1 → N, and which is subjected to further conditions on higher fiber products Y[3], Y[4] and Y[5]. String structures can be described and classified using 2-crossed module bundle 2-gerbes.
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R.-Grandjean, A., et M. Ladra. « On totally free crossed modules ». Glasgow Mathematical Journal 40, no 3 (septembre 1998) : 323–32. http://dx.doi.org/10.1017/s0017089500032675.
Texte intégralRésumé :
In [10] we associate to a crossed module (T, G, მ) an invariant abelian crossed module H2(T, G, მ). The construction uses presentations by Set-free crossed modules. Now, Set-free crossed modules are special cases of totally free crossed modules, which are algebraic models of 2-dimensional CW complexes used by several authors (see [1] and [6]). The aim of this paper is to show that H2(T, G, მ) can also be constructed from presentations by arbitrary totally free crossed modules.
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Noohi, Behrang. « Group cohomology with coefficients in a crossed module ». Journal of the Institute of Mathematics of Jussieu 10, no 2 (17 juin 2010) : 359–404. http://dx.doi.org/10.1017/s1474748010000186.
Texte intégralRésumé :
AbstractWe compare three different ways of defining group cohomology with coefficients in a crossed module: (1) explicit approach via cocycles; (2) geometric approach via gerbes; (3) group theoretic approach via butterflies. We discuss the case where the crossed module is braided and the case where the braiding is symmetric. We prove the functoriality of the cohomologies with respect to weak morphisms of crossed modules and also prove the ‘long’ exact cohomology sequence associated to a short exact sequence of crossed modules and weak morphisms.
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ALP, MURAT. « ENUMERATION OF WHITEHEAD GROUPS OF LOW ORDER ». International Journal of Algebra and Computation 12, no 05 (octobre 2002) : 645–58. http://dx.doi.org/10.1142/s0218196702001176.
Texte intégralRésumé :
In this paper we describe a share package of functions for computing with finite, permutation crossed modules, cat1-groups and their morphisms, written using the [Formula: see text] group theory programming language. The category XMod of crossed modules is equivalent to the category Cat1 of cat1-groups and we include functions emulating the functors between these categories. The monoid of derivations of a crossed module [Formula: see text], and the corresponding monoid of sections of a cat1-group [Formula: see text], are constructed using the Whitehead multiplication. The Whitehead group of invertible derivations, together with the group of automorphisms of X, are used to construct the actor crossed module of X which is the automorphism object in XMod. We include a table of the 350 isomorphism classes of cat1-structures on groups of order at most 30 in [2].
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Zucchini, Roberto. « On higher holonomy invariants in higher gauge theory II ». International Journal of Geometric Methods in Modern Physics 13, no 07 (25 juillet 2016) : 1650091. http://dx.doi.org/10.1142/s0219887816500912.
Texte intégralRésumé :
This is the second of a series of two technical papers devoted to the analysis of holonomy invariants in strict higher gauge theory with end applications in higher Chern–Simons theory. We provide a definition of trace over a crossed module to yield surface knot invariants upon application to 2-holonomies. We show further that the properties of the trace are best described using the theory quandle crossed modules.
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Akça, İlker, Kadir Emir et João Faria Martins. « Two-fold homotopy of 2-crossed module maps of commutative algebras ». Communications in Algebra 47, no 1 (5 décembre 2018) : 289–311. http://dx.doi.org/10.1080/00927872.2018.1476523.
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Gohla, Björn, et João Faria Martins. « Pointed homotopy and pointed lax homotopy of 2-crossed module maps ». Advances in Mathematics 248 (novembre 2013) : 986–1049. http://dx.doi.org/10.1016/j.aim.2013.08.020.
Texte intégral
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Cai, Xiongwei. « Transgression maps for crossed modules of groupoids ». International Journal of Mathematics 32, no 09 (9 juin 2021) : 2150061. http://dx.doi.org/10.1142/s0129167x21500610.
Texte intégralRésumé :
Given a crossed module of groupoids [Formula: see text], we construct (1) a natural homomorphism from the product groupoid [Formula: see text] to the crossed product groupoid [Formula: see text] and (2) a transgression map from the singular cohomology [Formula: see text] of the nerve of the groupoid [Formula: see text] to the singular cohomology [Formula: see text] of the nerve of the crossed product groupoid [Formula: see text]. The latter turns out to be identical to the transgression map obtained by Tu–Xu in their study of equivariant [Formula: see text]-theory.
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Inassaridze, H. « Non-Abelian Cohomology of Groups ». gmj 4, no 4 (août 1997) : 313–31. http://dx.doi.org/10.1515/gmj.1997.313.
Texte intégralRésumé :
Abstract Following Guin's approach to non-abelian cohomology [Guin, Pure Appl. Algebra 50: 109–137, 1988] and, using the notion of a crossed bimodule, a second pointed set of cohomology is defined with coefficients in a crossed module, and Guin's six-term exact cohomology sequence is extended to a nine-term exact sequence of cohomology up to dimension 2.
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Trentinaglia, Giorgio, et Chenchang Zhu. « Strictification of étale stacky Lie groups ». Compositio Mathematica 148, no 3 (30 novembre 2011) : 807–34. http://dx.doi.org/10.1112/s0010437x11007020.
Texte intégralRésumé :
AbstractWe define stacky Lie groups to be group objects in the 2-category of differentiable stacks. We show that every connected and étale stacky Lie group is equivalent to a crossed module of the form (Γ,G) where Γ is the fundamental group of the given stacky Lie group and G is the connected and simply connected Lie group integrating the Lie algebra of the stacky group. Our result is closely related to a strictification result of Baez and Lauda.
Thèses sur le sujet "2-crossed module"
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PIZZAMIGLIO, LINDA. « Cohomologies of crossed modules ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2014. http://hdl.handle.net/10281/50169.
Texte intégralLivres sur le sujet "2-crossed module"
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Ellis, Graham. An Invitation to Computational Homotopy. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780198832973.001.0001.
Texte intégralRésumé :
This book is an introduction to elementary algebraic topology for students with an interest in computers and computer programming. Its aim is to illustrate how the basics of the subject can be implemented on a computer. The transition from basic theory to practical computation raises a range of non-trivial algorithmic issues and it is hoped that the treatment of these will also appeal to readers already familiar with basic theory who are interested in developing computational aspects. The book covers a subset of standard introductory material on fundamental groups, covering spaces, homology, cohomology and classifying spaces as well as some less standard material on crossed modules, homotopy 2- types and explicit resolutions for an eclectic selection of discrete groups. It attempts to cover these topics in a way that hints at potential applications of topology in areas of computer science and engineering outside the usual territory of pure mathematics, and also in a way that demonstrates how computers can be used to perform explicit calculations within the domain of pure algebraic topology itself. The initial chapters include examples from data mining, biology and digital image analysis, while the later chapters cover a range of computational examples on the cohomology of classifying spaces that are likely beyond the reach of a purely paper-and-pen approach to the subject. The applied examples in the initial chapters use only low-dimensional and mainly abelian topological tools. Our applications of higher dimensional and less abelian computational methods are currently confined to pure mathematical calculations. The approach taken to computational homotopy is very much based on J.H.C. Whitehead’s theory of combinatorial homotopy in which he introduced the fundamental notions of CW-space, simple homotopy equivalence and crossed module. The book should serve as a self-contained informal introduction to these topics and their computer implementation. It is written in a style that tries to lead as quickly as possible to a range of potentially useful machine computations.
Chapitres de livres sur le sujet "2-crossed module"
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« 2 Crossed modules of Lie algebras ». Dans Crossed Modules, 85–168. De Gruyter, 2021. http://dx.doi.org/10.1515/9783110750959-002.
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« The 2-Way Crossed Classification ». Dans Linear Models, 261–331. Hoboken, NJ, USA : John Wiley & Sons, Inc., 2012. http://dx.doi.org/10.1002/9781118491782.ch7.
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Ellis, Graham. « Cohomology of Homotopy 2-types ». Dans An Invitation to Computational Homotopy, 379–422. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780198832973.003.0005.
Texte intégralRésumé :
This chapter introduces some of the basic ingredients in the classification of homotopy 2-types and describes datatypes and algorithms for implementing them on a computer. These are illustrated using computer examples involving: the fundamental crossed modules of a CW-complex, cat-1-groups, simplicial groups, Moore complexes, the Dold-Kan correspondence, integral homology of simplicial groups, homological perturbation theory. A manual classification of homotopy classes of maps from a surface to the projective plane is also included.
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« Anadromous Sturgeons : Habitats, Threats, and Management ». Dans Anadromous Sturgeons : Habitats, Threats, and Management, sous la direction de Pierre Nellis, Simon Senneville, Jean Munro, Georges Drapeau, Daniel Hatin, Gaston Desrosiers et François J. Saucier. American Fisheries Society, 2007. http://dx.doi.org/10.47886/9781888569919.ch12.
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<em>Abstract.</em>—The short- and long-term impacts of the annual disposal of dredged sediment within Atlantic sturgeon <em>Acipenser oxyrinchus</em> habitat in the St. Lawrence estuary were assessed by simulating sediment transport over 10 years and by sampling sediment and macrobenthos on impacted and control radials. The model applied bed load transport functions embedded in a baroclinic hydrodynamic model. The path predicted by the model was validated at its half-way point (5 years) using multibeam sonar images of the seabed as well as qualitative and quantitative sediment analyses. Sediment took more than 1 year to completely clear the disposal site, indicating continuous sand drift along the predicted path. In the first 2 years, the sediment path increased rapidly in length (10 km), bypassing a field of sand dunes and following the deepest depressions (10 m) in the downstream direction. In the middle of its 10-year course (ca 12 km), the sediment track crossed the most important core area used by early juvenile Atlantic sturgeon. Afterward, sediment progression slowed and accumulated in a 15-mdeep channel between islands in the middle of the estuarine transition zone. The impact stations showed a significant reduction in the average biomass of tubificids, the most important food item of juvenile Atlantic sturgeon in the St. Lawrence. Conversely, the number and abundance of epi- and suprabenthic taxa increased. Model and field results suggest that sand drift generated from disposal operations reduces benthic productivity along the modeled path, including critical habitats of early juvenile Atlantic sturgeon. Sand accumulation from dredged spoil that drift in dead current areas are also likely to reduce juvenile sturgeon habitat quality.
Actes de conférences sur le sujet "2-crossed module"
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Sulake, Sandeep, Satish Kumar Dubey et Arshad Javed. « Numerical Heat Transfer Simulations and Parametric Investigations Using Crossed Array Design of Experiments Approach During RFA of Breast Tumor ». Dans ASME 2019 Heat Transfer Summer Conference collocated with the ASME 2019 13th International Conference on Energy Sustainability. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/ht2019-3469.
Texte intégralRésumé :
Abstract In the present work, a heterogeneous breast model comprising of fat, glandular and muscle tissues along with a spherical tumor of 2 cm diameter is modelled. The efficacy of Radio Frequency Ablation (RFA) is mainly judged by the extent to which the tumor cells are damaged and hence the volume fraction of necrotic tissue (VFNT) is a response parameter. Several critical factors affect the volume of necrotic tissue, among which the blood perfusion rate, target tip temperature of electrode and location of tumor from the body core are considered as prime input parameters. This work focuses on the selection and the significance of tolerance of these critical factors using ‘cross-array design of experiment’ (CA-DOE) approach. The loose and tight ranges of tolerances of these factors are selected to form Taguchi’s inner and outer orthogonal array and experimental combination sets are prepared. In this study, the effect of each possible set of tolerance on the output parameter i.e. tumor ablation volume generated is analyzed. The different values of the ablation volume generated for each experiment are obtained from finite element analysis. The entire analysis is carried out using a bioheat transfer module coupled with electric currents module in COMSOL multiphysics software. Additionally, target tip temperature is controlled by the implementation of proportional-integral-derivative control strategy. The simulations results are validated with the available published experimental results. The simulation results are further analyzed using statistical methods, such as signal to noise ratio, analysis of mean, and analysis of variance. The presented analysis will be helpful to achieve robust and targeted values of ablation volume with least effort of maintaining process accuracy. The proposed methodology and results are useful for clinicians in the RFA.
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Keating, Michael P. « Completely Dioptrically Equivalent Systems ». Dans Vision Science and its Applications. Washington, D.C. : Optica Publishing Group, 1997. http://dx.doi.org/10.1364/vsia.1997.sae.5.
Texte intégralRésumé :
The paraxial optics of astigmatic human eyes is covered by the optics of systems with obliquely crossed toric surfaces. For these systems, the dioptric parameters in terms of the 2 X 2 dioptric matrices are: the equivalent power matrix P e (which may be asymmetric), the back vertex power matrix P v , and the neutralizing or front vertex power matrix P n .1,2 For statistical considerations where thickness is taken into account (as opposed to a thin lens model), one might compute a mean P e , P v , and P n (10 known parameters).3,4 Since the means are statistical calculations and not optical calculations, the question then arises as to whether any real system of toric surfaces has the same dioptric parameters as these means. I'll refer to such matching systems as completely dioptrically equivalent (CDE) systems. These systems might be models of astigmatic eyes or general systems consisting of toric surfaces.
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Ferrari, Flavio, Davide Fenaroli, Jean Michelez et Jacopo Magni. « Integrated Rig Management Platform ». Dans ADIPEC. SPE, 2022. http://dx.doi.org/10.2118/211767-ms.
Texte intégralRésumé :
Abstract Objectives/Scope: The Integrated Rig Management System provides the implementation of a comprehensive digital platform to manage, analyse and display drilling data coming from different sources (rig sensors, reporting, equipment description, engines data, …). This integration fulfils several objectives such as empowering analytics, automatizing reporting, supporting operations performance, and rig management. Methods, Procedures, Process: The system is made of 5 modules, of which 2 directly operated on the rig: and 2 collecting data from all rigs: A Reporting module that gathers a full set of daily reports such as DDR, HSE report and BHA assembly,… This module also provides a connection between the planned and realized activities, in order to support maintenance and logistics. A Multi-Wells/Rigs Performance module that displays benchmark analyses from all rigs, by type of operation, and equipment, giving a statistical indication on the technical limit to reduce invisible lost time or greenhouse gases emissions. A Real-Time Operations Monitoring module that supports ongoing activities with powerful analyses and insightful performance KPIs. This module also supports the Reporting through the recognition of main rig states by analysing rig sensor data. A Predictive module that uses a predictive algorithm to anticipate and avoid wellbore issues with a machine learning approach.• A Data Manager module that aggregates and processes the data coming from the drilling rigs, combining it with daily drilling reporting. Results, Observations, Conclusions: The values generated by this Integrated Rig Management System are supporting all main corporate objectives in terms of operations, logistics and carbon footprint. Regarding the operations, the system provides impartial and detailed KPIs on operation performances, in order to calculate the Invisible Lost Time to be eliminated in future operations. The system has demonstrated up to 8% time and cost reduction on entire well campaigns. For the logistics, the system crosses the near future activities with any rig resources (equipment, services, personnel, ⋯). Through specific APIs the system makes information available to third parties solutions for maintenance, logistics ad personnel management. A considerable amount of time is saved by the integration of operational and organizational systems. Finally, considering the carbon footprint, the system provides analyses on how much each operation consumes in terms of energy and makes recommendations on how many diesel engines must be kept running in each situation to minimize the related GHG emissions. Novel/Additive Information: The main innovation is the integration of different objectives into one single platform. Reporting data and rig sensor data are obviously creating a great value to operations, but less commonly they also create value for maintenance, logistics, and GHG reduction. The system is in a continuous stream of upgrades, in order to integrate gradually different rig components and generate value wherever possible in terms of cost, reliability, and environmental impact.
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Muthukrishnan, N. « Machinability Studies and Artificial Neural Network Modeling of Turning Al-SiC (10p) Metal Matrix Composites ». Dans ASME 2008 International Mechanical Engineering Congress and Exposition. ASMEDC, 2008. http://dx.doi.org/10.1115/imece2008-66145.
Texte intégralRésumé :
The paper presents the results of an experimental investigation on the machinability of fabricated Aluminum metal matrix composite (A356/SiC/10p) during continuous turning of composite rods using medium grade Polycrystalline Diamond (PCD 1500) inserts. MMC’s are very difficult to machine and PCD tools are considered by far, the best choice for the machining of these materials. Experiments were conducted at LMW-CNC-LAL-2 production lathe using PCD 1500 grade insert at various cutting conditions and parameters such as surface roughness, specific power consumed, and tool wear were measured. Machining was continued till the flank wears land on the tool crossed 0.4 mm. The influences of cutting speed on the insert wear and built-up edges (BUEs) formation were studied. The present results reaffirm the suitability of PCD for machining MMCs. Though BUE formation was observed at low cutting speeds, at high cutting speeds very good surface finish and low specific power consumption could be achieved. An Artificial Neural Network (ANN) model has been developed for prediction of machinability parameters of MMC using feed forward back propagation algorithm. The various stages in the development of ANN models VIZ. selection of network type, input and output of the network, arriving at a suitable network configuration, training of the network, validation of the resulting network has been taken up. A 2-9-3 feed forward neural network has been successfully trained and validated to act as a model for predicting the machining parameters of Al-SiC (10p) -MMC. The ANN models after successful training are able to predict the surface quality; specific power consumption and tool wear for a given set of input values of cutting speed and machining time.
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Petrov, Nikolai, Nikolai Petrov, Inna Nikonorova, Inna Nikonorova, Vladimir Mashin et Vladimir Mashin. « LANDSLIDE RISK MANAGEMENT IN THE COASTAL ZONE OF THE KUIBYSHEV RESERVOIR DUE THE DESIGN OF HIGH-SPEED LINE "MOSCOW-KAZAN" ». Dans Managing risks to coastal regions and communities in a changing world. Academus Publishing, 2017. http://dx.doi.org/10.31519/conferencearticle_5b1b9403c99983.72529271.
Texte intégralRésumé :
High-speed railway "Moscow-Kazan" by the draft crosses the Volga (Kuibyshev reservoir) in Chuvashia region 500 m below the village of New Kushnikovo. The crossing plot is a right-bank landslide slope with a stepped surface. Its height is 80 m; the slope steepness -15-16o. The authors should assess the risk of landslides and recommend anti-landslide measures to ensure the safety of the future bridge. For this landslide factors have been analyzed, slope stability assessment has been performed and recommendations have been suggested. The role of the following factors have been analyzed: 1) hydrologic - erosion and abrasion reservoir and runoff role; 2) lithologyc (the presence of Urzhum and Northern Dvina horizons of plastically deformable rocks, displacement areas); 3) hydrogeological (the role of perched, ground and interstratal water); 4) geomorphological (presence of the elemental composition of sliding systems and their structure in the relief); 5) exogeodynamic (cycles and stages of landslide systems development, mechanisms and relationship between landslide tiers of different generations and blocks contained in tiers). As a result 6-7 computational models at each of the three engineering-geological sections were made. The stability was evaluated by the method “of the leaning slope”. It is proved that the slope is in a very stable state and requires the following measures: 1) unloading (truncation) of active heads blocks of landslide tiers) and the edge of the plateau, 2) regulation of the surface and groundwater flow, 3) concrete dam, if necessary.
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Petrov, Nikolai, Nikolai Petrov, Inna Nikonorova, Inna Nikonorova, Vladimir Mashin et Vladimir Mashin. « LANDSLIDE RISK MANAGEMENT IN THE COASTAL ZONE OF THE KUIBYSHEV RESERVOIR DUE THE DESIGN OF HIGH-SPEED LINE "MOSCOW-KAZAN" ». Dans Managing risks to coastal regions and communities in a changing world. Academus Publishing, 2017. http://dx.doi.org/10.21610/conferencearticle_58b4315fbf636.
Texte intégralRésumé :
High-speed railway "Moscow-Kazan" by the draft crosses the Volga (Kuibyshev reservoir) in Chuvashia region 500 m below the village of New Kushnikovo. The crossing plot is a right-bank landslide slope with a stepped surface. Its height is 80 m; the slope steepness -15-16o. The authors should assess the risk of landslides and recommend anti-landslide measures to ensure the safety of the future bridge. For this landslide factors have been analyzed, slope stability assessment has been performed and recommendations have been suggested. The role of the following factors have been analyzed: 1) hydrologic - erosion and abrasion reservoir and runoff role; 2) lithologyc (the presence of Urzhum and Northern Dvina horizons of plastically deformable rocks, displacement areas); 3) hydrogeological (the role of perched, ground and interstratal water); 4) geomorphological (presence of the elemental composition of sliding systems and their structure in the relief); 5) exogeodynamic (cycles and stages of landslide systems development, mechanisms and relationship between landslide tiers of different generations and blocks contained in tiers). As a result 6-7 computational models at each of the three engineering-geological sections were made. The stability was evaluated by the method “of the leaning slope”. It is proved that the slope is in a very stable state and requires the following measures: 1) unloading (truncation) of active heads blocks of landslide tiers) and the edge of the plateau, 2) regulation of the surface and groundwater flow, 3) concrete dam, if necessary.
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Poon, Chun Ting, Connor Mullins, Lukas Radziunas, Enda O’Connell, Aengus Connolly et Sean Leen. « Finite Element Design Study of Dynamics in Submarine Power Cables for Offshore Renewable Wind Energy ». Dans ASME 2022 4th International Offshore Wind Technical Conference. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/iowtc2022-98245.
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Abstract The future of energy in Ireland will include significant emphasis on offshore renewable energy due to the country’s excellent marine resources, with a potential 70 GW of ocean energy available within 100 km of the Irish coastline [1]. A key challenge to improving uptake of offshore wind energy is the reliability of power transmission via submarine power cables (SPCs). Dynamic cables associated with floating offshore wind turbines are critical infrastructure that consist of a complex arrangement of sub-components with different functions, including strength, insulation and corrosion resistance. Fretting, wear, and fatigue have been demonstrated as key contributing factors to damage and failure of cable conductors within laboratory testing of SPCs [2]. This paper presents a finite element design study for dynamic power cables based on a systematic model development relating an offshore submarine cable with a representative laboratory test arrangement. Initially a global finite element model is developed to replicate a floating wind turbine with attached dynamic cable via Flexcom [3] and OpenFAST [4] (without fretting fatigue damage) operating in an offshore marine environment. Simplified SPC and multi-strand wire models are developed using Abaqus [5] to understand the localised fretting conditions between individual wires. The results of these models are implemented into a localised and highly detailed frictional contact model, constructed to represent a crossed-cylinder laboratory fretting test arrangement, using results from the global assessment as boundary conditions. The localised finite element analysis (FEA) is used to predict potential fretting fatigue damage. This research aims to develop a systematic methodology for fretting fatigue in SPC copper conductors, helping to identify suitable design aspects (e.g., lay angle, lay direction, wire diameter, and number of layers) for reduction of fretting fatigue damage and extension of cable service life.
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Selvam, R. Panneer, et Suranjan Sarkar. « Equilibrium Molecular Dynamics Simulation Study on the Effect of Nanoparticle Loading and Size on Thermal Conductivity of Nanofluids ». Dans ASME/JSME 2007 Thermal Engineering Heat Transfer Summer Conference collocated with the ASME 2007 InterPACK Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/ht2007-32314.
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Nanofluids have been proposed as a route for surpassing the performance of currently available heat transfer liquids for better thermal management needed in many diverse industries and research laboratories. Recent experiments on nanofluids have indicated a significant increase in thermal conductivity with 0.5 to 2% of nanoparticle loading in comparison to that of the base fluid. But the extent of thermal conductivity enhancement sometimes greatly exceeds the predictions of well established classical theories like Maxwell and Hamilton Crosser theory. In addition to that, these classical theories can not explain the temperature and nanoparticle size dependency of nanofluid thermal conductivity. Atomistic simulation like molecular dynamics simulation can be a very helpful tool to model the enhanced nanoscale thermal conduction and predict thermal conductivities in different situations. In this study a model nanofluid system of copper nanoparticles in argon base fluid is successfully modeled by equilibrium molecular dynamics simulation in NVT ensemble and thermal conductivities of base fluid and nanofluids are computed using Green Kubo method. The interatomic interactions between solid copper nanoparticles, base liquid argon atoms and between solid copper and liquid argon are modeled by Lennard Jones potential with appropriate parameters. For different volume fractions of nanoparticle loading, the thermal conductivities are calculated. The nanoparticle size effects on thermal conductivities of nanofluids are also systematically studied. This study indicates the usefulness of MD simulation to calculate thermal conductivity of nanofluid and explore the higher thermal conduction in molecular level.
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Krolikowski, W., et Mark Cronin-Golomb. « Photorefractive wave mixing with finite beams ». Dans OSA Annual Meeting. Washington, D.C. : Optica Publishing Group, 1991. http://dx.doi.org/10.1364/oam.1991.mu1.
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While the interaction of optical beams in photorefractive crystals can often be accurately described in terms of 1-D plane-wave approximation, 2-D models are sometimes more suitable, as suggested by recent work.1 Here we discuss some aspects of photorefractive interaction of finite size optical beams. We have solved the system of partial differential equations governing two- and four-wave mixing numerically by using iterative procedures. Simulations of beam amplification in two-beam coupling show strong beam deformation even without any spatial information imposed on them. Spatially nonuniform energy transfer is responsible for this effect. The pump beam loses energy during propagation and at the end of its passage through the beam intersection region (which was completely inside the crystal) it is strongly depleted and cannot contribute significantly to beam amplification. As the pump beam crosses through the probe, it amplifies most strongly that side of the probe that it meets first. By the time the pump has reached the far side of the probe, it is strongly depleted and less effective at probe amplification. In the case of phase conjugation through four-wave mixing, we found that the conjugate beam is strongly deformed only when the coupling constant is negative (corresponding to deamplification of the probe input beam). For positive coupling constants the output conjugate beam is a good replica of the input probe beam.
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Sas, G. « DEFECTS IN SERINE PROTEASE INHIBITORS ». Dans XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643714.
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Several serine protease inhibitorsof plasma inhibit the activated coagulation enzymes but only antithrombin III(AT-III)and heparin cofactor II (HC-II) are implicated in the pathogenesisof the familial thrombosis. Since thefirst publication (1965) many thrombophilic families with reduced AT-III synthesis have been investigated. These studies have proved that the disorder is associated with a high risk forvenous thrombosis and the inheritanceis autosomal dominant. The AT-III activity in the plasma of the affected patients is about 50% of the normalvalue.In recent years the heterogeneity of the inherited AT-III deficiency has been verified. The various AT-III abnormalities are not mere interestingrarities but they provide naturally occurring models for the solution of theoretical problems such as the function of AT-III molecule, the physiological significance of heparin, etc. Furthermore, the clinical manifestationof the particular variants greatly differs from symptomless abnormality tosevere thrombotic cases.In the majority of cases, reduced functional activity is accompanied with a parallel decrease of antigen concentration of AT-III. This is the characteristic feature of the quantitative or Type I ("classical")AT-III deficiency. By means of crossed immunoelectrophoresis, electro-focussing and recombinant DNA techniques the heterogeneity of this group has been established. In one subgroup (Type la) AT-III molecules are normal as regards their biochemical characteristics. In Type lb, subnormal AT-IIIquantity is accompanied with decreased heparin affinity. Differentiation of these subgroups has practical consequences: therapeutic concentrations of heparin apparently does not decrease AT-III level in the plasma of patients with Type lb AT-III deficiency.The other main form is the qualitative deficiency of AT-III (Type II) which is characterised by reduced functional activity at normal antigen concentration. In general, two populations of AT-III molecules can be detected in the blood of these patients: a normal and an abnormal one. Up till now at least 24 different abnormalities were found and designatedwith toponymes. These disorders can be classified with relatively simple laboratory methods such as functional anti-IIaXaFirstDepartment of Medicine, Postgraduate Medical University, Budapest, Hungary.arin cofactor activity, crossed immunoelectrophoresiswith and without heparin, heparin-affinity chromatography. Type na is characterised by profound structural changes of the molecule,variably: reflected in reduced inactivation of F Ha and F Xa, abnormal heparin-AT-III reaction and aberrant immunochemical structure Seven different abnormalities fall into this group (Budapest I, Tokyo, MalmÖ, Chicago, Milano, Trento and Northwick Park). The last three abnormalities are very similar.In Type lib an isolated defect of protease inactivation can be detected and an isolated disturbance of the active centre ofthe molecule is assumed.Until now 6 apparently different variants belonging to this group have been described. (Aalborg, Vicenza, Denver, Hvidovre, Charleville, Milano 2.) Type lie abnormality is characterised by an isolated defect of the heparin-AT-III reaction. In these cases a disturbance of the heparin binding site(s) is assumed. Eleven families with this type of abnormality have been recorded (Ann Arbor, Basel, Paris 1 and 2, Toyama* Tours, Padova I and 2, Algers, Fontainebleu and Budapest 2). This subgroup is heterogeneous in respect ofheparin affinity: in the majority of cases the abnormal AT-III molecules have no heparin affinity at all while in rare cases (such as Basel, Budapest 2) they have reduced affinity.TheType lie AT-III deficiency has several distinctive features compared with the other subtypesJClinically, the thromboembolic complications are rare: in 4 families thrombosis has notoccurred at all. Only one member in each of 4 other families had thrombosis. In 3 families homozygous patients suffered severe thrombosis in young age and/or in unusual localisations (intraarterial, intracardiac, etc.) butthe other heterozygous members were free of thrombotic symptoms. No increased intravascular coagulation could be detected in Type lie heterozygous cases incontrast to the "classical" AT-III deficiency.These observations suggest a different mechanism and clinical manifestation of the deficiency of progressiveserine protease inactivation and of heparin cofactor activity. In case of progressive inactivation, reduction of 50% of the activity predisposes mainly to venous thrombosis as a consequence of the hypercoagulability of theblood. The isolated reduction of heparin cofactor activity seems to bringabout thrombosis in any part of the vascular system, but only if this reduction is as severe as that of the coagulant factors in case of coagulopathies.In accordance with this finding, rare cases of HCII deficiency give rise to thrombosis in both the arteries and the veins. Heparin cofactor activities may play an important role in the antithrombotic mechanism along theendothelial surface of the whole vascular system.
Rapports d'organisations sur le sujet "2-crossed module"
1
Gur, Amit, Edward Buckler, Joseph Burger, Yaakov Tadmor et Iftach Klapp. Characterization of genetic variation and yield heterosis in Cucumis melo. United States Department of Agriculture, janvier 2016. http://dx.doi.org/10.32747/2016.7600047.bard.
Texte intégralRésumé :
Project objectives: 1) Characterization of variation for yield heterosis in melon using Half-Diallele (HDA) design. 2) Development and implementation of image-based yield phenotyping in melon. 3) Characterization of genetic, epigenetic and transcriptional variation across 25 founder lines and selected hybrids. The epigentic part of this objective was modified during the course of the project: instead of characterization of chromatin structure in a single melon line through genome-wide mapping of nucleosomes using MNase-seq approach, we took advantage of rapid advancements in single-molecule sequencing and shifted the focus to Nanoporelong-read sequencing of all 25 founder lines. This analysis provides invaluable information on genome-wide structural variation across our diversity 4) Integrated analyses and development of prediction models Agricultural heterosis relates to hybrids that outperform their inbred parents for yield. First generation (F1) hybrids are produced in many crop species and it is estimated that heterosis increases yield by 15-30% globally. Melon (Cucumismelo) is an economically important species of The Cucurbitaceae family and is among the most important fleshy fruits for fresh consumption Worldwide. The major goal of this project was to explore the patterns and magnitude of yield heterosis in melon and link it to whole genome sequence variation. A core subset of 25 diverse lines was selected from the Newe-Yaar melon diversity panel for whole-genome re-sequencing (WGS) and test-crosses, to produce structured half-diallele design of 300 F1 hybrids (MelHDA25). Yield variation was measured in replicated yield trials at the whole-plant and at the rootstock levels (through a common-scion grafted experiments), across the F1s and parental lines. As part of this project we also developed an algorithmic pipeline for detection and yield estimation of melons from aerial-images, towards future implementation of such high throughput, cost-effective method for remote yield evaluation in open-field melons. We found extensive, highly heritable root-derived yield variation across the diallele population that was characterized by prominent best-parent heterosis (BPH), where hybrids rootstocks outperformed their parents by 38% and 56 % under optimal irrigation and drought- stress, respectively. Through integration of the genotypic data (~4,000,000 SNPs) and yield analyses we show that root-derived hybrids yield is independent of parental genetic distance. However, we mapped novel root-derived yield QTLs through genome-wide association (GWA) analysis and a multi-QTLs model explained more than 45% of the hybrids yield variation, providing a potential route for marker-assisted hybrid rootstock breeding. Four selected hybrid rootstocks are further studied under multiple scion varieties and their validated positive effect on yield performance is now leading to ongoing evaluation of their commercial potential. On the genomic level, this project resulted in 3 layers of data: 1) whole-genome short-read Illumina sequencing (30X) of the 25 founder lines provided us with 25 genome alignments and high-density melon HapMap that is already shown to be an effective resource for QTL annotation and candidate gene analysis in melon. 2) fast advancements in long-read single-molecule sequencing allowed us to shift focus towards this technology and generate ~50X Nanoporesequencing of the 25 founders which in combination with the short-read data now enable de novo assembly of the 25 genomes that will soon lead to construction of the first melon pan-genome. 3) Transcriptomic (3' RNA-Seq) analysis of several selected hybrids and their parents provide preliminary information on differentially expressed genes that can be further used to explain the root-derived yield variation. Taken together, this project expanded our view on yield heterosis in melon with novel specific insights on root-derived yield heterosis. To our knowledge, thus far this is the largest systematic genetic analysis of rootstock effects on yield heterosis in cucurbits or any other crop plant, and our results are now translated into potential breeding applications. The genomic resources that were developed as part of this project are putting melon in the forefront of genomic research and will continue to be useful tool for the cucurbits community in years to come.
2
Levy, Maggie, Raymond Zielinski et Anireddy S. Reddy. IQD1 Function in Defense Responses. United States Department of Agriculture, janvier 2012. http://dx.doi.org/10.32747/2012.7699842.bard.
Texte intégralRésumé :
The main objective of the proposed research was to study IQD1's mechanism of action and elucidate its role in plant protection. Preliminary experiments suggest that IQD1 binds CaM in a Ca²⁺-dependent manner and functions in general defense responses. We propose to identify proteins and genes that interact with IQD1, which may provide some clues to its mechanism of action. We also plan to dissect IQD1's integration in defense pathways and to study and modulate its binding affinity to CaM in order to enhance crop resistance. Our specific objectives were: (1) Analysis of IQD1's CaM-binding properties; (2) Identification of IQD1 targets;(3) Dissection of IQD1 integration into defense signaling pathways. Analysis of IQD1's CaM-binding properties defined four potential classes of sequences that should affect CaM binding: one is predicted to raise the affinity for Ca²⁺-dependent interaction but have no effect on Ca²⁺-independent binding; a second is predicted to act like the first mutation but eliminate Ca²⁺-independent binding; a third has no predicted effect on Ca²⁺-dependent binding but eliminates Ca²⁺-independent binding; and the fourth is predicted to eliminate or greatly reduce both Ca²⁺-dependent and Ca²⁺-independent binding. Following yeast two hybrid analysis we found that IQD1 interact with AtSR1 (Arabidopsis thalianaSIGNALRESPONSIVE1), a calcium/calmodulin-binding transcription factor, which has been shown to play an important role in biotic and abiotic stresses. We tested IQD1 interaction with both N-terminal or C-terminal half of SR1. These studies have uncovered that only the N-terminal half of the SR1 interacts with the IQD1. Since IQD1 has an important role in herbivory, its interaction with SR1 suggests that it might also be involved in plant responses to insect herbivory. Since AtSR1, like IQD1, is a calmodulin-binding protein and the mutant showed increased sensitivity to a herbivore, we analyzed WT, Atsr1 and the complemented line for the levels of GS to determine if the increased susceptibility of Atsr1 plants to T. ni feeding is associated with altered GS content. In general, Atsr1 showed a significant reduction in both aliphatic and aromatic GS levels as compared to WT. In order to study IQD1's molecular basis integration into hormone-signaling pathways we tested the epistatic relationships between IQD1 and hormone-signaling mutants. For that purpose we construct double mutants between IQD1ᴼXᴾ and mutants defective in plant-hormone signaling and GS accumulation. Epitasis with SA mutant NahG and npr1-1 and JA mutant jar1-1 suggested IQD1 function is dependent on both JA and SA as indicated by B. cinerea infection assays. We also verified the glucosinolate content in the crosses siblings and found that aliphatic GSL content is reduced in the double transgenic plants NahG:IQD1ᴼXᴾ as compare to parental lines while the aliphatic GSL content in the npr1-1:IQD1ᴼXᴾ and jar1-1: IQD1ᴼXᴾ double mutants was intimidated to the parental lines. This suggests that GSL content dependency on SA is downstream to IQD1. As a whole, this project should contribute to the development of new defense strategies that will improve crop protection and reduce yield losses and the amount of pesticides required; these will genuinely benefit farmers, consumers and the environment.
3
Aharoni, Asaph, Zhangjun Fei, Efraim Lewinsohn, Arthur Schaffer et Yaakov Tadmor. System Approach to Understanding the Metabolic Diversity in Melon. United States Department of Agriculture, juillet 2013. http://dx.doi.org/10.32747/2013.7593400.bard.
Texte intégralRésumé :
Fruit quality is determined by numerous genetic factors that affect taste, aroma, color, texture, nutritional value and shelf life. To unravel the genetic components involved in the metabolic pathways behind these traits, the major goal of the project was to identify novel genes that are involved in, or that regulate, these pathways using correlation analysis between genotype, metabolite and gene expression data. The original and specific research objectives were: (1) Collection of replicated fruit from a population of 96 RI lines derived from parents distinguished by great diversity in fruit development and quality phenotypes, (2) Phenotypic and metabolic profiling of mature fruit from all 96 RI lines and their parents, (3) 454 pyrosequencing of cDNA representing mRNA of mature fruit from each line to facilitate gene expression analysis based on relative EST abundance, (4) Development of a database modeled after an existing database developed for tomato introgression lines (ILs) to facilitate online data analysis by members of this project and by researchers around the world. The main functions of the database will be to store and present metabolite and gene expression data so that correlations can be drawn between variation in target traits or metabolites across the RI population members and variation in gene expression to identify candidate genes which may impact phenotypic and chemical traits of interest, (5) Selection of RI lines for segregation and/or hybridization (crosses) analysis to ascertain whether or not genes associated with traits through gene expression/metabolite correlation analysis are indeed contributors to said traits. The overall research strategy was to utilize an available recombinant inbred population of melon (Cucumis melo L.) derived from phenotypically diverse parents and for which over 800 molecular markers have been mapped for the association of metabolic trait and gene expression QTLs. Transcriptomic data were obtained by high throughput sequencing using the Illumina platform instead of the originally planned 454 platform. The change was due to the fast advancement and proven advantages of the Illumina platform, as explained in the first annual scientific report. Metabolic data were collected using both targeted (sugars, organic acids, carotenoids) and non-targeted metabolomics analysis methodologies. Genes whose expression patterns were associated with variation of particular metabolites or fruit quality traits represent candidates for the molecular mechanisms that underlie them. Candidate genes that may encode enzymes catalyzingbiosynthetic steps in the production of volatile compounds of interest, downstream catabolic processes of aromatic amino acids and regulatory genes were selected and are in the process of functional analyses. Several of these are genes represent unanticipated effectors of compound accumulation that could not be identified using traditional approaches. According to the original plan, the Cucurbit Genomics Network (http://www.icugi.org/), developed through an earlier BARD project (IS-3333-02), was expanded to serve as a public portal for the extensive metabolomics and transcriptomic data resulting from the current project. Importantly, this database was also expanded to include genomic and metabolomic resources of all the cucurbit crops, including genomes of cucumber and watermelon, EST collections, genetic maps, metabolite data and additional information. In addition, the database provides tools enabling researchers to identify genes, the expression patterns of which correlate with traits of interest. The project has significantly expanded the existing EST resource for melon and provides new molecular tools for marker-assisted selection. This information will be opened to the public by the end of 2013, upon the first publication describing the transcriptomic and metabolomics resources developed through the project. In addition, well-characterized RI lines are available to enable targeted breeding for genes of interest. Segregation of the RI lines for specific metabolites of interest has been shown, demonstrating the utility in these lines and our new molecular and metabolic data as a basis for selection targeting specific flavor, quality, nutritional and/or defensive compounds. To summarize, all the specific goals of the project have been achieved and in many cases exceeded. Large scale trascriptomic and metabolomic resources have been developed for melon and will soon become available to the community. The usefulness of these has been validated. A number of novel genes involved in fruit ripening have been selected and are currently being functionally analyzed. We thus fully addressed our obligations to the project. In our view, however, the potential value of the project outcomes as ultimately manifested may be far greater than originally anticipated. The resources developed and expanded under this project, and the tools created for using them will enable us, and others, to continue to employ resulting data and discoveries in future studies with benefits both in basic and applied agricultural - scientific research.
4
STUDY ON FORCE MECHANISM OF CABLE-TRUSS FRAME AND JUMPED LAYOUT OF ANNULAR CROSSED CABLE-TRUSS STRUCTURE. The Hong Kong Institute of Steel Construction, septembre 2021. http://dx.doi.org/10.18057/ijasc.2021.17.3.3.
Texte intégralRésumé :
A new type of cable-strut tension structure named Annular Crossed Cable-truss Structure(ACCTS) comprises a series of planar cable-truss frames crossed each other. To investigate the force mechanism of ACCTS, a cable-truss frame model with 2-bar and 6-cable has been developed, and its initial stiffness formula has been derived as well. The model is further simplified to make it is upper and lower vector heights equal, and then the initial stiffness formula and the critical slack load formula are further deduced. Based on ANSYS software and cable-truss frame with a span of 60m, the influences of the number of struts and position of jumped layout on the cable-truss frame are studied. According to the former 60m span cable-truss frame's research results, the jumped layout of ACCTS with a span of 100m is studied. The static and dynamic performances of two schemes, the optimal jumped layout scheme and the original scheme, are systematically studied. It is shown that the number of struts would be about 6~8 for the planar cable-truss frame and the optimal order of jumped layout is strut 6-7→strut 4-5→strut 2-3. The optimal order of jumped layout of ACCTS agrees with that of the cable-truss frame, verifying the feasibility of conclusions. In the condition of no variation in the original structure's static and dynamic performance, the optimal scheme of the jumped layout will lower the steel consumption and enhance the buckling loads. Moreover, it also simplifies structure for easy construction.