Migration von Iod-129 und retrospektive Dosimetrie

[no abstract

Freeze-drying modeling and monitoring using a new neuro-evolutive technique

This paper is focused on the design of a black-box model for the process of freeze-drying of pharmaceuticals. A new methodology based on a self-adaptive differential evolution scheme is combined with a back-propagation algorithm, as local search method, for the simultaneous structural and parametric optimization of the model represented by a neural network. Using the model of the freeze-drying process, both the temperature and the residual ice content in the product vs. time can be determine off-line, given the values of the operating conditions (the temperature of the heating shelf and the pressure in the drying chamber). This makes possible to understand if the maximum temperature allowed by the product is trespassed and when the sublimation drying is complete, thus providing a valuable tool for recipe design and optimization. Besides, the black box model can be applied to monitor the freeze-drying process: in this case, the measurement of product temperature is used as input variable of the neural network in order to provide in-line estimation of the state of the product (temperature and residual amount of ice). Various examples are presented and discussed, thus pointing out the strength of the too

Plutonium in Soils from Northeast China and Its Potential Application for Evaluation of Soil Erosion

Surface and soil core samples from northeast China were analyzed for Pu isotopes. The measured Pu-240/Pu-239 atomic ratios and Pu239 + 240/Cs-137 activity ratios revealed that the global fallout is the dominant source of Pu and Cs-137 at these sites. Migration behavior of Pu varying with land type and human activities resulted in different distribution of Pu in surface soils. A sub-surface maximum followed by exponential decline of Pu239 + 240 concentrations was observed in an undisturbed soil core, with a total Pu239 + 240 inventory of 86.9 Bq/m(2) and more than 85% accumulated in 0 similar to 20 cm layers. While only half inventory of Pu was obtained in another soil core and no sub-surface maximum value occurred. Erosion of topsoil in the site should be the most possible reason for the significantly lower Pu inventory, which is also supported by the reported Cs-137 profiles. These results demonstrated that Pu could be applied as an ideal substitute of Cs-137 for soil erosion study in the future.</p

Benefits in using model based predictive control during drying and lyophilisation

International audienceSince 1998 [3], the yearly mean publication rate of papers using a first principle model for control has been multiplied by 11! This increase is quiet similar to the increase of the control papers in drying based on optimal control strategies, like MPC. With 60 000 products dried and 100 dryer types used worldwide [1], a real potential exists. With control tools like MPC, it is expected that the industrial drying operation will continue to improve its energy efficiency while enhancing product quality and reducing the negative environmental impact of dryers

Quadrotor Attitude estimation with data losses

International audienceThis paper deals with the attitude estimation of a quadrotor in the presence of measurement losses. This situation may appear when the quadrotor is controlled through a network. The attitude estimation is a prerequisite to the implementation of any kind of control law. Moreover, the attitude cannot be directly measured and different sensor modalities must be used. The observer implemented is an Extended Kalman Filter derived from the Kalman Filter previously proposed by Sinopoli et al. The loss of data is modeled with a random process. The lost measurement is replaced with zero, the corresponding variance being set to an arbitrarily large value. All the scenarios that have been tested show the capability of the filter to properly estimate the quadrotor attitude even in the presence of a high rate of data loss. Experiments have been performed with a Matlab/Simulink simulator of the quadrotor developed at the GIPSA-Lab laboratory

Model predictive control of the primary drying stage of the drying of solutions in vials: an Application of the MPC@CB Software (Part 1)

More open archives publications of Pascal Dufour are available on: http://hal.archives-ouvertes.fr/DUFOUR-PASCAL-C-3926-2008International audienceThis paper deals with the first principle model based predictive control of the primary drying stage of a freeze drying of solutions in vials. In the proposed control approach, any online control problem concerned with a constrained optimization during the primary drying stage may be stated. It is solved using a special model predictive control framework where the model is used in the controller formulation. Our first simulation results show here the efficiency of the control software developed (MPC@CB) under Matlab. MPC@CB may be easily used for any other process and any constrained control problem

Data-loss tolerant Extended Kalman Filter for a quadrotor attitude estimation

This paper deals with the problem of attitude estimation for an Unmanned Aerial Vehicle (UAV) with four rotors using an Extended Kalman Filter (EKF) when data losses are considered. Actually, this situation may arise when control of the quadrotor is performed through a network. The quadrotor attitude is estimated with measurements from an Inertial Measurement Unit (IMU) composed of 3 rate gyros, a triaxis accelerometer and a triaxis magnetometer. A modified EKF is proposed that takes into account data losses . To model the data losses, the covariance matrix (R) associated with the measurement equation is modified in order to attach less confidence in the measurement that has been lost