35 research outputs found

    The simulation of dynamic systems using combined modelling

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    The new approach to the problems of dynamic systems simulation is proposed. The analytical and imitation modelling of non‐linear complex dynamic systems which comprise simulation of continuous and discrete processes with constant and variable parameters, are investigated. The aggregate mathematical modelling scheme [1] and the method of control sequences for discrete systems specification and simulation are used as well as the dynamic mathematical modelling scheme for continuous process formalization and modelling. According to them the investigated systems are presented as the set of interacting piecewise linear aggregates, which can include processes described with differential equations. The above mentioned approach is used in developing software for the construction and research of the models. The modelling of the dynamic systems’ control is also analyzed and developed software for the dynamic systems’ simulation is presented. It is related to the proposed combined modelling methodology. The developed dynamical simulation system ADPRO (Automatic Differentiation PROgram) extends applicability of the system SIMAS (SIMulation of the Aggregate Systems) [2] with dynamical simulation means realized with APL2 (A Programming Language 2) and based on automatic differentiation [3]. The created model of service process and its control can be used as a base for other models of wide class complex dynamics’ systems [4], the parts of which are described with differential equations. Dinaminių sistemų kombinuotas modeliavimas Santrauka Darbe nagrinejamas naujas dinaminiu sistemu modeliavimo metodas. Ištirti analitiniai ir imitaciniai sudetingu dinaminiu sistemu modeliavimo būdai, tirti tolydieji ir diskretieji procesai. Pateikta nauja dinaminio matematinio modeliavimo schema, skirta tolydžiu procesu formalizavimui ir modeliavimui. Sukurta programine iranga, leidžianti sudaryti ir tirti tokio tipo matematinius modelius. Taip pat tirtas dinaminiu sistemu valdymo modeliavimas bei sukurta atitinkama programine iranga. First Published Online: 14 Oct 201

    Heat Treatment Process Energy Efficient Design and Optimisation

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    AbstractEnergy efficiency optimization ICT (Information and Communication Technology) solutions are currently being developed for energy saving in buildings and, to some ex-tent, also for the manufacturing domain. This paper describes an approach and ICT tool developed for manufacturing process energy efficiency optimization, in particular focused on the heat treatment process of steel casting parts. Traditionally this manufacturing process is designed based on experts experience selecting a predefined temperature-time curve provided customer specifications for the resulting steel parts. However this curve can actually be optimised in terms of energy consumption while keeping required mechanical properties. This improved design is what the tool here described provides, using knowledge based approach for process design and multivariate optimisation and simulation techniques for process optimisation

    Emergence and spread of SARS-CoV-2 lineage B.1.620 with variant of concern-like mutations and deletions

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    Distinct SARS-CoV-2 lineages, discovered through various genomic surveillance initiatives, have emerged during the pandemic following unprecedented reductions in worldwide human mobility. We here describe a SARS-CoV-2 lineage - designated B.1.620 - discovered in Lithuania and carrying many mutations and deletions in the spike protein shared with widespread variants of concern (VOCs), including E484K, S477N and deletions HV69Delta, Y144Delta, and LLA241/243Delta. As well as documenting the suite of mutations this lineage carries, we also describe its potential to be resistant to neutralising antibodies, accompanying travel histories for a subset of European cases, evidence of local B.1.620 transmission in Europe with a focus on Lithuania, and significance of its prevalence in Central Africa owing to recent genome sequencing efforts there. We make a case for its likely Central African origin using advanced phylogeographic inference methodologies incorporating recorded travel histories of infected travellers

    Connected Health in Europe: Where are we today?

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    This report, which has grown out of an ENJECT survey of 19 European countries, examines the situation of Connected Health in Europe today. It focuses on creating a clear understanding of the current and developing presence of Connected Health throughout European healthcare systems under five headings: The Policy Environment, Education, Business and Health Models, Interoperability, and The Perso

    Towards a new image processing system at Wendelstein 7-X: From spatial calibration to characterization of thermal events

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    Wendelstein 7-X (W7-X) is the most advanced fusion experiment in the stellarator line and is aimed at proving that the stellarator concept is suitable for a fusion reactor. One of the most important issues for fusion reactors is the monitoring of plasma facing components when exposed to very high heat loads, through the use of visible and infrared (IR) cameras. In this paper, a new image processing system for the analysis of the strike lines on the inboard limiters from the first W7-X experimental campaign is presented. This system builds a model of the IR cameras through the use of spatial calibration techniques, helping to characterize the strike lines by using the information given by real spatial coordinates of each pixel. The characterization of the strike lines is made in terms of position, size, and shape, after projecting the camera image in a 2D grid which tries to preserve the curvilinear surface distances between points. The description of the strike-line shape is made by means of the Fourier Descriptors

    Forward modeling of collective Thomson scattering for Wendelstein 7-X plasmas: Electrostatic approximation

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    In this paper, we present a method for numerical computation of collective Thomson scattering (CTS). We developed a forward model, eCTS, in the electrostatic approximation and benchmarked it against a full electromagnetic model. Differences between the electrostatic and the electromagnetic models are discussed. The sensitivity of the results to the ion temperature and the plasma composition is demonstrated. We integrated the model into the Bayesian data analysis framework Minerva and used it for the analysis of noisy synthetic data sets produced by a full electromagnetic model. It is shown that eCTS can be used for the inference of the bulk ion temperature. The model has been used to infer the bulk ion temperature from the first CTS measurements on Wendelstein 7-X

    THE SIMULATION OF DYNAMIC SYSTEMS USING COMBINED MODELLING

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    IRIS reactor design overview and status update

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    The International Reactor Innovative and Secure (IRIS) is an advanced, integral, light-water cooled reactor of medium generating capacity (1000 MWt, or ∼335 MWe), geared at near term deployment (2012-2015). It has been under development since the turn of the century by an international consortium - led by Westinghouse - that includes 21 organizations from 10 countries, and it is currently in the pre-application licensing process with the U.S. Nuclear Regulatory Commission (NRC). This paper describes its integral design (i.e., steam generators, pumps, pressurizer and control rod drive mechanisms are all included inside the reactor vessel, together with the core, control rods, and neutron reflector/shield) and discusses the unique "safety-by- design"™ IRIS philosophy. This approach, by eliminating accidents at the design stage, or decreasing their consequences and probabilities when outright elimination is not possible, provides a very powerful first level of defense in depth. The "safety-by-design"™ allows a significant reduction and simplification of the passive safety systems, which not only improves safety but simultaneously reduces the overall cost. Moreover, it supports licensing the power plant without the need for off-site emergency response planning - an objective which is part of the pre-application with NRC and is also pursued within an international research project coordinated by the International Atomic Energy Agency (IAEA). This would allow IRIS to be treated as any other industrial facility, located closer to population centers, and enable its effective dual-purpose use for electricity production and co-generation (district heating, desalination, industrial steam)Lietuvos energetikos institutasLietuvos energetikos institutas, [email protected]

    Small Reactors without On-site Refuelling: Neutronic Characteristics, Emergency Planning and Development Scenarios

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    Small reactors without on-site refuelling have a capability to operate without reloading or shuffling of fuel in their cores for reasonably long periods of time consistent with plant economy and considerations of energy security, with no fresh or spent fuel being stored at the site during reactor operation. In 2009, more than 25 design concepts of such reactors were analyzed or developed in IAEA Member States, representing both developed and developing countries. Small reactors without on-site refuelling are being developed for several reactor lines, including water cooled reactors, sodium cooled fast reactors, lead and lead bismuth cooled reactors, and also include some non-conventional concepts. To further research and development (R&D) in the areas mentioned above and several others, and to facilitate progress in Member States in design and technology development for small reactors without on-site refueling, the IAEA has conducted a dedicated Coordinated Research Project (CRP) entitled ‘Small Reactors without On-site Refuelling’ (CRPi25001). The project started late in 2004 and, after a review in 2008, was extended for one more year to be ended in 2009. The project has created a network of 18 research institutions from 10 Member States, representing both developed and developing countries. The objective of this report is to document reference points and conclusions achieved through coordinated research conducted within the CRP on ‘Small Reactors without On-site Refuelling’ and to suggest R&D activities to be furthered after the CRP completion. Being documented, the outputs of this CRP may foster further R&D and increase the capability of Member States to achieve progress in development and deployment of small reactors without on-site refuelling
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