Search results for "WTO"
showing 10 items of 163 documents
The Development of a new Philosophy of Physics in the 18th Century
2012
The study of books on physics published in the 18th century shows that the evolution since the 17th century is much more than just a furthering of the discoveries of Newton, as we often tend to present it these days. Descartes’s mechanistic physics, severely criticized by Newton, was to develop with help from many scientists, particularly from the Academy of Sciences in Paris. The discussions between Cartesians and Newtonians did not end in the 1740’s. This real scientific duel, which lasted over half a century, was the heart of a broader way of thinking about physics which operated on several levels: Mathématization, Concepts, définitions, laws, the role of experimentation and hypotheses, …
A multi-scale method for complex flows of non-Newtonian fluids
2021
We introduce a new heterogeneous multi-scale method for the simulation of flows of non-Newtonian fluids in general geometries and present its application to paradigmatic two-dimensional flows of polymeric fluids. Our method combines micro-scale data from non-equilibrium molecular dynamics (NEMD) with macro-scale continuum equations to achieve a data-driven prediction of complex flows. At the continuum level, the method is model-free, since the Cauchy stress tensor is determined locally in space and time from NEMD data. The modelling effort is thus limited to the identification of suitable interaction potentials at the micro-scale. Compared to previous proposals, our approach takes into acco…
Freshman Engineering’ Reasoning Strategies When Answering FCI Questions: A Case Study
2020
Force Concept Inventory (FCI) is a questionnaire commonly used to assess students’ conceptual understanding of Newtonian Mechanics. We show that Cluster Analysis methods can be used to study student answers to FCI by finding their reasoning strategies on Newtonian Mechanics. Our analysis is performed to data obtained by a sample of freshman engineering students just at the beginning of their first General Physics course. The analysis takes into account the decomposition of the force concept into the conceptual dimensions suggested by test authors and successive researches. We identified groups of students with similar answering strategies, characterised by correct answers, as well as by non…
Dimensión socio-laboral de las relaciones comerciales trasatlánticas: algunas lecciones del pasado.
2022
En la cumbre UE-EE.UU. del pasado 15 de junio de 2021, la Unión Europea y los Estados Unidos realizaron una declaración conjunta en la que anunciaron una asociación transatlántica renovada para la era posterior a la pandemia. De manera que en el momento en el que se refuerzan las negociaciones comerciales entre la UE y EE.UU. vale la pena analizar hasta dónde se llegó en las negociaciones del Acuerdo Transatlántico sobre Comercio e Inversión en el marco de la OMC, en particular en relación a los aspectos más controvertidos desde la perspectiva social. Lo que incluye un análisis comparado específicamente enfocado al tratamiento del desplazamiento de trabajadores en el AGCS y en la Directiva …
Coronal properties of G-type stars in different evolutionary phases
2005
We report on the analysis of XMM-Newton observations of three G-type stars in very different evolutionary phases: the weak-lined T Tauri star HD 283572, the Zero Age Main Sequence star EK Dra and the Hertzsprung-gap giant star 31 Com. They all have high X-ray luminosity (10^31 erg/s for HD 283572 and 31 Com and 10^30 erg/s for EK Dra). We compare the Emission Measure Distributions (EMDs) of these active coronal sources, derived from high-resolution XMM-Newton grating spectra, as well as the pattern of elemental abundances vs. First Ionization Potential (FIP). We also perform time-resolved spectroscopy of a flare detected by XMM from EK Dra. We interpret the observed $EMD$s as the result of …
Physics at the grocery store
2022
The motion of a food can on an accelerated conveyor belt in a grocery store is described by means of Newtonian mechanics. By assuming that the food can may roll on the conveyor belt, when the cashier starts this device, one can prove that the rolling motion, observed in the belt reference system, is such that the can is seen to move away for the cashier. Experiments can be performed with common material: an empty and a full food can, and a sheet of paper as conveyor belt.
Post-post-Newtonian effects on a clean nearly-Newtonian binary
1983
Etude du taux de changement temporel moyen de l'energie newtonienne et du moment d'une binaire presque newtonienne, ponctuelle. On trouve qu'il faut ajouter quelques termes post-post newtoniens non seculaires aux flux radiatifs seculaires standards. Les termes post-post newtoniens tendent vers zero pour l'observateur du centre de masse newtonien dans le cas de l'energie mais pas dans le cas du moment. Du fait de la longue periode de ces termes ils sont observationnellement significatifs, c'est-a-dire qu'ils vont apparaitre comme s'ils etaient des effets seculaires
Relativistic simulations of rotational core collapse : II. Collapse dynamics and gravitational radiation
2002
We have performed hydrodynamic simulations of relativistic rotational supernova core collapse in axisymmetry and have computed the gravitational radiation emitted by such an event. Details of the methodology and of the numerical code have been given in an accompanying paper. We have simulated the evolution of 26 models in both Newtonian and relativistic gravity. Our simulations show that the three different types of rotational supernova core collapse and gravitational waveforms identified in previous Newtonian simulations (regular collapse, multiple bounce collapse, and rapid collapse) are also present in relativistic gravity. However, rotational core collapse with multiple bounces is only …
Apparent universality of semiclassical gravity in the far field limit
2006
The universality of semiclassical gravity is investigated by considering the behavior of the quantities < ��^2 > and < {T^a}_b >, along with quantum corrections to the effective Newtonian potential in the far field limits of static spherically symmetric objects ranging from stars in the weak field Newtonian limit to black holes. For scalar fields it is shown that when differences occur they all result from the behavior of a single mode with zero frequency and angular momentum and are thus due to a combination of infrared and s-wave effects. An intriguing combination of similarities and differences between the extreme cases of a Schwarzschild black hole and a star in the weak fie…
Damping by bulk and shear viscosity for confined acoustic phonons of a spherical virus in water
2007
International audience; A sphere-like virus in water is modeled as a homogeneous isotropic elastic continuum sphere in contact with an infinite viscous compressible Newtonian fluid. The frequencies and damping of the confined vibrational modes of the sphere are calculated for the material parameters of a virus in water. While the effects of viscosity are found to be negligible for a virus-like sphere of macroscopic size, for nanoscale viruses both the frequency and damping of the vibrational modes are significantly affected by the viscosity of the water. Furthermore, both shear viscosity and bulk viscosity play an important role.