Insects and other pests in Africa

One of the most important bean-production constraints in tropical and subtropical Africa is the wide range of insect pests, which attack every part of the bean plant (from roots to pods and seeds) causing heavy losses either in the field or in storage. Losses can be up to 100 percent depending on area, season, cv., planting date, and cultural practices. Ophiomyia phaseoli, which attacks seedlings, is the most important pest. The main damage is caused by larval feeding and tunneling in stem tissue. Seedlings suffer premature leaf fall and either die or become stunted. Control is done through cultural practices, the use of insecticides, and var. resistance. Liriomyza trifolii is an important pest in Egypt and Mauritius; damage is caused by the maggot which destroys leaf's palisade tissue, making serpentine tunnels. It is controlled with insecticides and the use of resistant cv. Aphis favae and Aphis craccivora are the main aphid pests affecting common beans and cowpea. Their feeding causes leaf yellowing, destruction, yield losses, and transmit and spread BCMV. Control measures include the use of insecticides and resistant cv.Una de las mas importantes limitaciones a la produccion del frijol en Africa tropical y subtropical es el amplio rango de insectos plaga que atacan cada parte de la planta de frijol (raices, vainas, semillas) causando grandes perdidas en el campo o en almacenamiento. Las perdidas pueden ser de hasta 100 por ciento dependiendo del area, la estacion, el cv., la fecha de siembra y las practicas culturales. Ophiomyia phaseoli, que ataca las plantulas, es la plaga mas importante. El principal dano es causado por la alimentacion de larvas y la construccion de tuneles en el tejido del tallo. Las plantulas sufren senescencia foliar prematura y se danan o atrofian. Se controla mediante practicas culturales, uso de insecticidas y var. resistentes. Liriomyza trifolii es una plaga importante en Egipto y Mauricio; el dano es causado por la larva que destruye el tejido de empalizada de la hoja, contruyendo tuneles serpenteantes. Se controla con insecticidas y con el uso de var. resistentes. Aphis fabae y Aphis craccivora son los principales afidos que atacan al frijol comun y al caupi. Su alimentacion ocasiona amarillamiento foliar, destruccion, perdidas

A teaching experimental system for defect localisation based on frequency analysis in a thermal context

The aim of this paper is to present a newly developed pedagogical demonstrator. It is intended for students which study automated systems and computer engineering). This experimental device can be used as a support to illustrate the course on the identification of systems and more precisely to underline the interest of frequency analysis. It can be obviously implemented as part of a Master\u27s course allowing to deepen concepts specific to signal processing, filtering or even identification and diagnosis. It is mainly concerned with the teaching of information technology and information systems

Non-destructive inspection of polymer sample using a periodically moving heating source

Introduction The development of innovative materials with specific properties requires the design of non-destructive testing methods. The proposed study is focused on the localization of a possible defect in a polymer sample. In such an aim, a frequency analysis based on a periodic heating can reveal the defect location (see authors previous works). However this approach is usually time-consuming and this feature could reduce the method attractiveness in an industrial context. In the proposed communication, a new protocol has been developed in order to reduce the inspection duration. Methods Let us consider that the material to be studied is a polymer plate. On the upper face of this plate, a radiative heater is considered. Its power supply is kept constant. Its spatial distribution is limited to a disc of small radius r. Moreover, this source moves circularly so as to heat the plate. Once the steady state established, the temperature at each point of the sample is periodic. The frequency of the oscillations is related to the angular velocity of the source. Two observable characteristics of these "thermal waves" can then be taken into account at each point of the surface: the modulus and the phase shift of the thermograms. It has been shown that modulus is more relevant for defect location. Results and Discussion An example of thermograms is shown on figure I. The contrast distribution (difference of two cartographies of modulus with and without defect) is presented on figure II. Considering this numerical example, the whole plate inspection is performed and methods feasibility is exposed. Several concrete results based on our experimental device will be exposed during the conference

Python based internet tools in contriol education

The general language and opensource Python, coupled with its scientific libraries, offers an interesting alternative to Matlab, Java, and C++ for the development of scientific applications. In this context, authors present the main features of the language, associated tools, architecture and the diversity of its scientific environment. Three applications related to control education are presented: programming from a web browser (for system identification and PID tuning) and embedded computing (for motors control)

Quasi-online parametric identification of moving heating devices in a 2D geometry

This work is devoted to an adaptation of the conjugate gradient method for the identification of heat flux densities provided by two mobile sources on a two-dimensional geometry. This adaptation is based on a sliding-time window in order to achieve quasi-online identification of unknown time-dependent parameters. The proposed method ensures sequential in time iterative regularization in order to deal with the ill-posed nature of inverse heat conduction problem (IHCP). The studied configuration is issued from experimental reflections in order to investigate a practical case. A set of fixed sensors is considered while heating sources trajectories are accurately known. Measurements provided by sensors are disturbed according to a realistic Gaussian noise. Several strategies are detailed in this communication (adaptive integration interval, sliding time window, initialization improvement, choice of the sliding window size). In each situation, the benefit in terms of delay reduction is discussed in regards with the identification accuracy. It is shown that such methodology provides an attractive procedure consistent with adaptive control aims and real time signal processing

Quasi online sensors positioning for heating source tracking

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