Search results for " simulations"
showing 10 items of 243 documents
Influence of Skin Depth on Convective Heat Transfer in Induction Heating
2017
International audience; We investigate convection driven by induction heating of a horizontal fluid layer using direct numerical simulations (DNS). This problem is of particular interest in the context of nuclear severe accident mastering. In a real severe accident, the molten core is subjected to homogeneous internal sources resulting from nuclear disintegrations. This situation is mimicked in the laboratory using induction heating as the internal source. In induction heating, however, heat sources are localized in the skin layer. Consequently, this concentration of heat may modify the flow and wall heat transfer compared to the case of homogeneous internal sources. DNS are carried out for…
Integrated Simulation and Formal Verification of a Simple Autonomous Vehicle
2018
This paper presents a proof-of-concept application of an approach to system development based on the integration of formal verification and co-simulation. A simple autonomous vehicle has the task of reaching an assigned straight path and then follow it, and it can be controlled by varying its turning speed. The correctness of the proposed control law has been formalized and verified by interactive theorem proving with the Prototype Verification System. Concurrently, the system has been co-simulated using the Prototype Verification System and the MathWorks Simulink tool: The vehicle kinematics have been simulated in Simulink, whereas the controller has been modeled in the logic language of t…
Novel σ1 antagonists designed for tumor therapy: Structure – activity relationships of aminoethyl substituted cyclohexanes
2021
Abstract Depending on the substitution pattern and stereochemistry, 1,3-dioxanes 1 with an aminoethyl moiety in 4-position represent potent σ1 receptor antagonists. In order to increase the stability, a cyclohexane ring first replaced the acetalic 1, 3-dioxane ring of 1. A large set of aminoethyl substituted cyclohexane derivatives was prepared in a six-step synthesis. All enantiomers and diastereomers were separated by chiral HPLC at the stage of the primary alcohol 7, and their absolute configuration was determined by CD spectroscopy. Neither the relative nor the absolute configuration had a large impact on the σ1 affinity. The highest σ1 affinity was found for cis-configured benzylamines…
First principles simulation of amorphous InSb
2013
Ab initio molecular dynamics simulations based on density functional theory have been performed to generate a model of amorphous InSb by quenching from the melt. The resulting network is mostly tetrahedral with a minor fraction ($10%$) of atoms in a fivefold coordination. The structural properties are in good agreement with available x-ray diffraction and extended x-ray-absorption fine structure data and confirm the proposed presence of a sizable fraction of homopolar In-In and Sb-Sb bonds whose concentration in our model amounts to about $20%$ of the total number of bonds.
Pattern formation in clouds via Turing instabilities
2020
Pattern formation in clouds is a well-known feature, which can be observed almost every day. However, the guiding processes for structure formation are mostly unknown, and also theoretical investigations of cloud patterns are quite rare. From many scientific disciplines the occurrence of patterns in non-equilibrium systems due to Turing instabilities is known, i.e. unstable modes grow and form spatial structures. In this study we investigate a generic cloud model for the possibility of Turing instabilities. For this purpose, the model is extended by diffusion terms. We can show that for some cloud models, i.e special cases of the generic model, no Turing instabilities are possible. However,…
Sodium bis(2-ethylhexyl)sulfosuccinate self-aggregation in vacuo: molecular dynamics simulation.
2010
Molecular dynamics (MD) simulations were conducted for systems in vacuo consisting of n AOT(-) anions (bis(2-ethylhexyl)sulfosuccinate ions) and n+/- 1 or n Na(+) ions up to n = 20. For n = 15, positively charged systems with Li(+), K(+), and Cs(+) cations were also considered. All systems were observed to form reverse micelle-like aggregates whose centre is occupied by cations and polar heads in a very compact solid-like way, while globally the aggregate has the form of an elongated and rather flat ellipsoid. Various types of statistical analyses were carried out on the systems to enlighten structural and dynamical properties including gyration radius, atomic pair correlation functions, at…
Estimation of statistical time-to-cure in cancer patients
2019
Three million people are living in France with a personal past of cancer and undergo difficulties in accessing loans and insurance. Since 2016, the French law « modernisation de notre système de santé » set the "right to be forgotten" (time beyond which insurance applicants with a past of cancer will no longer have to declare it) at 10 years after the end of treatment. From a statistical point of view, this delay can be considered as the time from which mortality due to cancer (excess mortality) disappears. After this time, the net survival curves reach a plateau corresponding to the proportion of cured patients. The verification of this hypothesis is based on two criteria: a negligible exc…
A rational expectations model for simulation and policy evaluation of the Spanish economy
2010
This paper presents the model used for simulation purposes within the Spanish Ministry of Economic Affairs and Finance. REMS (a Rational Expectations Model for the Spanish economy) is a small open economy dynamic general equilibrium model in the vein of the New-Neoclassical-Keynesian synthesis models, with a strongly micro-founded system of equations. In the long run REMS behaves in accordance with the neoclassical growth model. In the short run, it incorporates nominal, real and financial frictions. Real frictions include adjustment costs in consumption (via habits in consumption and rule-of-thumb households) and investment into physical capital. Due to financial frictions, there is no per…
Monte Carlo simulation of the energy released by neutrons on organic compounds for EPR dosimetry
2022
In this work we report the analyses of the energy released per unit mass in organic compounds used for EPR dosimetry exposed to neutron beams in order to predict the increase in dose achievable by addition of gadolinium (Gd) inside the pellets. In particular, Monte Carlo (MC) simulations were carried out for alanine, ammonium tartrate and phenolic compounds irradiated with neutron beams with different energy spectra at various depths inside a water phantom. The addition of gadolinium increases sensitivity of these dosimeters to neutrons thanks to the high gadolinium cross section for neutron capture and to the large number of secondary particles (mainly Auger and internal conversion electro…
Ettringite surface chemistry: Interplay of electrostatic and ion specificity
2011
International audience; This paper presents a detailed experimental study combined with Monte Carlo (MC) simulations within the primitive model of the physical chemistry at the ettringite-water interface over a wide range of pH and bulk conditions for which ettringite exists thanks to its solubility in aqueous solutions. Ettringite, which is an important phase in hydrated cement-based systems, bears a permanent and positive structural charge. In contrast with previous studies, electrokinetic measurements together with the careful chemical analysis of the equilibrium solutions of the dispersions have brought strong support to designate sulfate as being the ion determining the potential. Simu…