Optimization of Milking Frequency in Dairy Ruminants

To make a decision on the number of milkings per day for each ruminant is a key factor to optimize the use of a machine milking. Currently, this decision is mainly taken from yield and stage of lactation data, but no udder capacity is taken into account. Milk is stored in the udder in the alveolar and cisternal compartments. Milk partitioning in the udder varied widely according to species, breed, lactation stage, parity, and milking interval. The increase in milking frequency has improved milk production in dairy ruminants. However, this practice reduces the milk composition, fertility, and productive life. To avoid increasing the number of milkings per day and reducing milk losses, a strategy based on the selection of ruminants with large udder cistern to store a large quantity of milk was adopted. Animals with great cisterns tolerate extended milking intervals and are milked faster with simplified routines. Ultrasonography will be a useful tool to measure udder cistern and to predict high-yielding animals. In practice, we propose to use the evaluation of udder cistern area, as helping criteria of udder milk storage capacity, establishing the optimal milking frequencies for each ruminant according to the production system

Evaluación de la estructura interna de la ubre mediante ecografía y efectos de la frecuencia de ordeño en vacas lecheras

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One-dimensional Lumped-Circuit for Transient Thermal Study of an Induction Electric Motor

Electrical machines lifetime and performances could be improved when along the design process both electromagnetic and thermal behaviors are taken into account. Moreover, real time information about the device thermal state is necessary to an appropriate control with minimized losses. Models based on lumped parameter thermal circuits are: generic, rapid, accurate and qualified as a convenient solution for power systems. The purpose of the present paper is to validate a simulation platform intended for the prediction of the thermal state of an induction motor covering all operation regimes.  To do so, in steady state, the proposed model is validated using finite element calculation and experimental records. Then, in an overload situation, obtained temperatures are compared to finite element’s ones. It has been found that, in both regimes, simulation results are with closed proximity to finite element’s ones and experimental records

An LMI Technique for the Global Stabilization of Nonlinear Polynomial Systems

This paper deals with the global asymptotic stabilization of nonlinear polynomial systems within the framework of Linear Matrix Inequalities (LMIs). By employing the well-known Lyapunov stability direct method and the Kronecker product properties, we develop a technique of designing a state feedback control law which stabilizes quadratically the studied systems. Our main goal is to derive sufficient LMI stabilization conditions which resolution yields a stabilizing control law of polynomial systems