Process Identification through Test on Cryogenic System

UNICOS (UNified Industrial Control System) is the CERN object-based control standard for the cryogenics of the LHC and its experiments. It includes a variety of embedded functions, dedicated to the specific cryogenic processes. To enlarge the capabilities of the standard it is proposed to integrate the parametrical identification step in the control system of large scale cryogenic plants. Different methods of parametrical identification have been tested and the results were combined to obtain a better model. The main objective of the work is to find a compromise between an easy-to-use solution and a good level of process identification model. The study focuses on identification protocol for large delayed system, the measurement consistency and correlation between different inputs and outputs. Furthermore the paper describes in details, the results and the tests carried out on parametrical identification investigations with large scale systems

Identification of mono-and few- layer graphene: Raman study

International audienceIn this theoretical work, the Raman spectra were analyzed by considering the origin of the G peak, its shape, position and relative intensity as a function of the number of graphene layers. By using the spectral moment's method, the Raman spectra of mono, bi and few-layers of graphene are calculated and a good agreement was found with group theory concerning the number of the Raman-active modes and the Raman measurements. Our results provide a Raman analysis to evaluate the number of layers in multilayer graphene

Processus d'eutrophisation : activité de la phosphatase alcaline du microplancton d'un réservoir mésotrophe marocain (Allal El Fassi)

L'activité de la phosphatase alcaline (APA) bactérienne et phytoplanctonique a été mesurée bimensuellement du mois de mars au mois de décembre 1998 au sein d'un réservoir mésotrophe situé dans une zone à climat semi-aride (Allal El Fassi, Maroc). Les résultats montrent que l'APA totale est importante (0,107-1,780 mmol PNP·l-1·h-1) et majoritairement d'origine bactérienne (> 60 %) au niveau de l'épilimnion, alors qu'elle est à dominance algale (> 58 %) dans le méta- et l'hypolimnion. L'absence de corrélation entre l'APA totale et les concentrations en orthophosphates suggère que l'hydrolyse par cette enzyme n'est pas significative dans le processus de régénération du phosphore dans ce réservoir. Par conséquent, l'APA ne pourrait pas être un indicateur fiable du déficit en phosphore dans le milieu.Bacterial and phytoplanktonic alkaline phosphatase activity (APA) was measured from march to December 1998 in the mesotrophic Allal El Fassi reservoir located in the semi-arid zone (Morocco). The total APA varied between 0.107-1.780 mmol PNP·L-1·h-1. In epilimnion, the bacterioplankton contributed significantly (> 60%) to total APA. In the meta and hypolimnion, the APA was predominantly algal (> 58%). No correlation between APA and orthophosphates indicate that the hydrolysis by this enzyme was not a significant process in recycling of phosphorus in Allal El Fassi reservoir. Consequently, the APA was not a valid test of phosphorus deficiency

A new T-S fuzzy model predictive control for nonlinear processes

Abstract: In this paper, a novel fuzzy Generalized Predictive Control (GPC) is proposed for discrete-time nonlinear systems via Takagi-Sugeno system based Kernel Ridge Regression (TS-KRR). The TS-KRR strategy approximates the unknown nonlinear systems by learning the Takagi-Sugeno (TS) fuzzy parameters from the input-output data. Two main steps are required to construct the TS-KRR: the first step is to use a clustering algorithm such as the clustering based Particle Swarm Optimization (PSO) algorithm that separates the input data into clusters and obtains the antecedent TS fuzzy model parameters. In the second step, the consequent TS fuzzy parameters are obtained using a Kernel ridge regression algorithm. Furthermore, the TS based predictive control is created by integrating the TS-KRR into the Generalized Predictive Controller. Next, an adaptive, online, version of TS-KRR is proposed and integrated with the GPC controller resulting an efficient adaptive fuzzy generalized predictive control methodology that can deal with most of the industrial plants and has the ability to deal with disturbances and variations of the model parameters. In the adaptive TS-KRR algorithm, the antecedent parameters are initialized with a simple K-means algorithm and updated using a simple gradient algorithm. Then, the consequent parameters are obtained using the sliding-window Kernel Recursive Least squares (KRLS) algorithm. Finally, two nonlinear systems: A surge tank and Continuous Stirred Tank Reactor (CSTR) systems were used to investigate the performance of the new adaptive TS-KRR GPC controller. Furthermore, the results obtained by the adaptive TS-KRR GPC controller were compared with two other controllers. The numerical results demonstrate the reliability of the proposed adaptive TS-KRR GPC method for discrete-time nonlinear systems

Raman active modes in single-walled boron nitride nanotube bundles

We use the spectral moments method in the framework of the bond-polarization theory to calculate polarized nonresonant Raman spectra of chiral and achiral bundles of single walled boron nitride nanotubes (BWBNNTs) as a function of their diameter and chirality. The Spectra are computed for infinite size of BWBNNTs. We used a Lennard-Jones potential to describe the van der waals intertube interactions between tubes in a bundle. We show that the Raman active modes in the low wave number region are very sensitive to the nanotube diameter. We found that for infinite nanotube bundles, additional Radial Breathing Like mode appears in the low wave number region. These results are useful to interpret the experimental Raman spectra of BWBNNTs

Nonresonant Raman Spectrum Of Boron Doped Single Walled Carbon Nanotubes

In the present work, We use a force constant model to study the vibrationnel modes of boron doped single walled carbon nanotubes. This model is used to calculate the nonresonant Raman spectra of these nanomaterials in the framework of bond-polarisation theory by using either direct diagonalisation of the dynamical matrix or the spectral moments method. The effect of substitution of carbon by boron atoms shows that the higher Raman frequency region is dominated by a broad bond whereas the lower one is characterized by a shift of radial bonds.In the present work, We use a force constant model to study the vibrationnel modes of boron doped single walled carbon nanotubes. This model is used to calculate the nonresonant Raman spectra of these nanomaterials in the framework of bond-polarisation theory by using either direct diagonalisation of the dynamical matrix or the spectral moments method. The effect of substitution of carbon by boron atoms shows that the higher Raman frequency region is dominated by a broad bond whereas the lower one is characterized by a shift of radial bonds

Le carcinome indifférencié des glandes salivaires

Le carcinome indifferencie primitif des glandes salivaires est rare. Son association avec le virus Epstein Barr, initialement decrite chez les esquimaux, est retrouvee dans la majorite des cas publies. Nous rapportons un nouveau cas tunisien survenu chez un homme age de 64 ans, revele par une tumefaction de la glande parotide gauche. Microscopiquement se discutait le caractere primitif ou secondaire de la tumeur, etaye par les examens complementaires. Le patient etait traite par une parotidectomie suivie d’un curage ganglionnaire et d’une radiotherapie. L’evolution etait favorable apres un an de recul.  Mots clès : Glande salivaire- Carcinome indifferencie- Virus Epstein Bar