252 research outputs found
On Refinements of Boolean and Parametric Modal Transition Systems
We consider the extensions of modal transition systems (MTS), namely Boolean
MTS and parametric MTS and we investigate the refinement problems over both
classes. Firstly, we reduce the problem of modal refinement over both classes
to a problem solvable by a QBF solver and provide experimental results showing
our technique scales well. Secondly, we extend the algorithm for thorough
refinement of MTS providing better complexity then via reductions to previously
studied problems. Finally, we investigate the relationship between modal and
thorough refinement on the two classes and show how the thorough refinement can
be approximated by the modal refinement
LTL Parameter Synthesis of Parametric Timed Automata
The parameter synthesis problem for parametric timed automata is undecidable
in general even for very simple reachability properties. In this paper we
introduce restrictions on parameter valuations under which the parameter
synthesis problem is decidable for LTL properties. The investigated bounded
integer parameter synthesis problem could be solved using an explicit
enumeration of all possible parameter valuations. We propose an alternative
symbolic zone-based method for this problem which results in a faster
computation. Our technique extends the ideas of the automata-based approach to
LTL model checking of timed automata. To justify the usefulness of our
approach, we provide experimental evaluation and compare our method with
explicit enumeration technique.Comment: 23 pages, extended versio
Vaporization behaviour of the Molten Salt Fast Reactor fuel: The LiF-ThF4-UF4 system
A selected composition of the initial fuel of the Molten Salt Fast Reactor (MSFR) is assessed by differential scanning calorimetry (DSC) for melting point determination and by Knudsen effusion mass spectrometry (KEMS) for vaporization behaviour. Partial vapour pressures and thermodynamic activities of the MSFR fuel mixture are discussed indicating departures from ideal behaviour, and further interpreted by phase equilibria calculations. The boiling point of the mixture is obtained extrapolating vapour pressure experimental results. New results on the vaporization behaviour of pure uranium tetrafluoride are presented, together with the ionization potentials of UF4 by electron impact
Synthesis of plutonium trifluoride by hydro-fluorination and novel thermodynamic data for the PuF3-LiF system
PuF3 was synthetized by hydro-fluorination of PuO2 and subsequent reduction of the product by hydrogenation. The obtained PuF3 was analysed by X-Ray Diffraction (XRD) and found phase-pure. High purity was also confirmed by the melting point analysis using Differential Scanning Calorimetry (DSC). PuF3 was then used for thermodynamic assessment of the PuF3-LiF system. Phase equilibrium points and enthalpy of fusion of the eutectic composition were measured by DSC. XRD analyses of selected samples after DSC measurement confirm that after solidification from the liquid, the system returns to a mixture of LiF and PuF3
RADIOLUCENT COMPOSITES PROVIDING HIGH RESISTANCE AGAINST STERILIZATION DECOMPOSITION
We present a study of radiolucent composite materials for use in medicine, providing suitable mechanical properties and high resistance against sterilization decomposition. The composites are composed of carbon (C), aramid or glass (R-glass) fabrics embedded in polydimethylsiloxane (PDMS), polyetheretherketone (PEEK) or polyphenylene sulfide (PPS) matrix. The effect of multiple steam sterilization processes on degrading the mechanical properties, structural integrity and hydrolytic decomposition of the composites was verified. The radiolucency of the composites was also investigated. The mechanical performance of ARAMID/PDMS composite is strongly influenced by the sterilization technique that is applied. The mechanical behavior of R-glass/PDMS composite during steam sterilization is negatively influenced by its porosity. The relatively high porosity of C/PDMS composite may lead to lower ultimate bending strength values, but in general its mechanical behavior is influenced only at a low rate by steam sterilization. On the basis of our analyses, we can state that both C/PEEK and C/PPS composites are good candidates for application as radiolucent materials providing resistance against sterilization decomposition
Quantitative Modal Transition Systems
International audienceThis extended abstract offers a brief survey presentation of the specification formalism of modal transition systems and its recent extensions to the quantitative setting of timed as well as stochastic systems. Some applications will also be briefly mentioned
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