ParisTech

About: ParisTech is a education organization based out in Paris, France. It is known for research contribution in the topics: Finite element method & Residual stress. The organization has 1888 authors who have published 1965 publications receiving 55532 citations. The organization is also known as: Paris Institute of Technology & ParisTech Développement.

Rules based voltage control for distribution networks combined with TSO- DSO reactive power exchanges limitations

Abstract: This article deals with the evolution of voltage and reactive power control strategies in distribution networks with distributed generation. First a comprehensive review of voltage control and reactive power management techniques is given. The gap between actual or short-term industrial possibilities of distribution grids and techniques proposed in literature is highlighted. A realistic control based on local rules using the reactive power capabilities of distributed generators, capacitor banks and on load tap changer (OLTC) voltage setpoint is then presented. Its objective is to control both distribution network voltages and reactive power flows at the Transport System Operator (TSO) - Distribution System Operator (DSO) interface. The proposed control allows limiting OLTC bounds and conflicts between local rules. At last, this paper presents simulations results based on French MV distribution network in order to depict the efficiency of such a control.

Critical Point in Space: A Quest for Universality

Abstract: The behavior of matter near a 2nd order phase transition is expected to obey universal features. In particular, fluids, liquid mixtures, polymers, which belong to the same class of universality (the class of fluids) should exhibit the same universal scaling laws for many thermodynamics and kinetic parameters. Critical point slowing down is the most notorious. Such divergence or convergence makes the class of fluids extremely sensitive to even minute external disturbances and especially gravity: on earth the fluid becomes compressed under its own weight. Compensating for these effects by space experiments and/or magnetic forces or isotopic density matching has led to enlarge our vision of universality for phase transition. New phenomena have been discovered by suppressing gravity effects, as the thermal “Piston Effect”, which leads to a paradoxical critical point speeding up and the apparent violation of the 2nd thermodynamic law. Another finding is concerned with the use of critical slowing down and weightlessness to investigate the dynamics of phase separation with no gravity-induced sedimentation. The key role of the coalescence of domains makes valid only two simple growth laws. The latter can be successfully applied to a quite different situation, the evolution laws in the well-known biological problem of sorting of embryonic cells. Due to the extreme sensitivity of fluids near their critical point, the effect of vibration can be investigated in much detail, using only one fluid, which represents the whole class of fluids. The investigation of the above thermal and phase transition problems under vibrations indeed suggests that a periodic excitation can act as a kind of artificial gravity, which induces thermal convection, speeds up phase transition and localizes the liquid and vapor phases perpendicular to it.

Enhancing the plant layout design process using X3DOM and a scalable web3D service architecture

Abstract: This paper presents an innovative model-driven architecture enabling 3D web-based design processes in the field of large complex building (LBC) projects, such as power plant construction. This work was motivated by proposing new ways of achieving 3D CAD tasks not only for highly complex and temporary organization in the design stages but also for the whole lifecycle of such installations, which may last several decades. in this particular scenario, it is very important to share the right information with the right stakeholder at the right time, to maintain a high level of knowledge sharing. Taking into account these challenges, we propose a first implementation of interactive 3D CAD editing tools, based on the X3DOM technology and driven by a knowledge layer which utilizes a complete reference data and rules management system. To store the CAD models, a Macro-Parametric Approach has been investigated and a 3D server has been added to the traditional PDM (Product or Plant Data Management) to execute remotely complex CAD operations. This is a very promising start to deploy lightweight and smart web3D CAD editing services for the AEC (Architecture Engineering Construction) and power industries.

Contribution of the periosteum to mandibular distraction.

Abstract: Mandibular distraction is a surgical process that progressively lengthens bone. To improve the distraction procedure and devices, the load of distraction and the mechanical strain of soft tissues during the process must be determined. We tested the assumption that it could be the periosteum primarily opposing distraction. Therefore we assessed the mechanical properties of the human mandibular periosteum and compared the stress-strain data with the torque measured on the activator during a cadaveric mandibular distraction. A 20 mm horizontal mandibular distraction was performed in 7 cadavers using standard distractors. Torque was measured with a torquemeter placed on the activation rods of the devices, providing a load (Lt) for each millimeter of distraction. In parallel, 18 periosteum samples were harvested from 9 cadaver mandibles. Uniaxial tensile tests were performed on the specimens and an estimated load (Lc) was calculated using periosteal stress-strain data and mandibular dimensions. During the distraction process, we observed an increase of the load Lt from 11.6 to 50.6 N. The periosteum exhibited a nonlinear viscoelastic stress-strain relationship, typical of biological tissues composed of collagen and elastin. The median Lc and Lt were not significantly different for the first millimeter of distraction. We demonstrated the periosteum is primarily responsible for opposing the distraction load.