Les aspects sanitaires du travail de la police auprès des consommateurs de drogues

Voir aussi version en allemand: Gesundheitliche Aspekte der Polizeiarbeit im Drogenbereich.

Mémoires de Vidocq, chef de la police de Sûreté, jusqu'en 1827. 3

Collection : Archives de la linguistique française ; 397

Mémoires de Vidocq, chef de la police de Sûreté, jusqu'en 1827. 4

Collection : Archives de la linguistique française ; 397

Mémoires de Vidocq, chef de la police de Sûreté, jusqu'en 1827. 1

Collection : Archives de la linguistique française ; 397

Mémoires de Vidocq, chef de la police de Sûreté, jusqu'en 1827. 2

Collection : Archives de la linguistique française ; 397

Torque vibration model of axial-flux surface-mounted permanent magnet synchronous machine

In order that the radius and thus ununiform structure of the teeth and otherelectrical and magnetic parts of the machine may be taken into consideration the calculation of an axial flux permanent magnet machine is, conventionally, doneby means of 3D FEM-methods. This calculation procedure, however, requires a lotof time and computer recourses. This study proves that also analytical methods can be applied to perform the calculation successfully. The procedure of the analytical calculation can be summarized into following steps: first the magnet is divided into slices, which makes the calculation for each section individually, and then the parts are submitted to calculation of the final results. It is obvious that using this method can save a lot of designing and calculating time. Thecalculation program is designed to model the magnetic and electrical circuits of surface mounted axial flux permanent magnet synchronous machines in such a way, that it takes into account possible magnetic saturation of the iron parts. Theresult of the calculation is the torque of the motor including the vibrations. The motor geometry and the materials and either the torque or pole angle are defined and the motor can be fed with an arbitrary shape and amplitude of three-phase currents. There are no limits for the size and number of the pole pairs nor for many other factors. The calculation steps and the number of different sections of the magnet are selectable, but the calculation time is strongly depending on this. The results are compared to the measurements of real prototypes. The permanent magnet creates part of the flux in the magnetic circuit. The form and amplitude of the flux density in the air-gap depends on the geometry and material of the magnetic circuit, on the length of the air-gap and remanence flux density of the magnet. Slotting is taken into account by using the Carter factor in the slot opening area. The calculation is simple and fast if the shape of the magnetis a square and has no skew in relation to the stator slots. With a more complicated magnet shape the calculation has to be done in several sections. It is clear that according to the increasing number of sections also the result will become more accurate. In a radial flux motor all sections of the magnets create force with a same radius. In the case of an axial flux motor, each radial section creates force with a different radius and the torque is the sum of these. The magnetic circuit of the motor, consisting of the stator iron, rotor iron, air-gap, magnet and the slot, is modelled with a reluctance net, which considers the saturation of the iron. This means, that several iterations, in which the permeability is updated, has to be done in order to get final results. The motor torque is calculated using the instantaneous linkage flux and stator currents. Flux linkage is called the part of the flux that is created by the permanent magnets and the stator currents passing through the coils in stator teeth. The angle between this flux and the phase currents define the torque created by the magnetic circuit. Due to the winding structure of the stator and in order to limit the leakage flux the slot openings of the stator are normally not made of ferromagnetic material even though, in some cases, semimagnetic slot wedges are used. In the slot opening faces the flux enters the iron almost normally (tangentially with respect to the rotor flux) creating tangential forces in the rotor. This phenomenon iscalled cogging. The flux in the slot opening area on the different sides of theopening and in the different slot openings is not equal and so these forces do not compensate each other. In the calculation it is assumed that the flux entering the left side of the opening is the component left from the geometrical centre of the slot. This torque component together with the torque component calculated using the Lorenz force make the total torque of the motor. It is easy to assume that when all the magnet edges, where the derivative component of the magnet flux density is at its highest, enter the slot openings at the same time, this will have as a result a considerable cogging torque. To reduce the cogging torquethe magnet edges can be shaped so that they are not parallel to the stator slots, which is the common way to solve the problem. In doing so, the edge may be spread along the whole slot pitch and thus also the high derivative component willbe spread to occur equally along the rotation. Besides forming the magnets theymay also be placed somewhat asymmetric on the rotor surface. The asymmetric distribution can be made in many different ways. All the magnets may have a different deflection of the symmetrical centre point or they can be for example shiftedin pairs. There are some factors that limit the deflection. The first is that the magnets cannot overlap. The magnet shape and the relative width compared to the pole define the deflection in this case. The other factor is that a shifting of the poles limits the maximum torque of the motor. If the edges of adjacent magnets are very close to each other the leakage flux from one pole to the other increases reducing thus the air-gap magnetization. The asymmetric model needs some assumptions and simplifications in order to limit the size of the model and calculation time. The reluctance net is made for symmetric distribution. If the magnets are distributed asymmetrically the flux in the different pole pairs will not be exactly the same. Therefore, the assumption that the flux flows from the edges of the model to the next pole pairs, in the calculation model from one edgeto the other, is not correct. If it were wished for that this fact should be considered in multi-pole pair machines, this would mean that all the poles, in other words the whole machine, should be modelled in reluctance net. The error resulting from this wrong assumption is, nevertheless, irrelevant.

First systematic chemical profiling of cocaine police seizures in Finland in the framework of an intelligence-led approach

For the first time in Finland, the chemical profiling of cocaine specimens was performed at the National Bureau of Investigation (NBI). The main goals were to determine the chemical composition of cocaine specimens sold in the Finnish market and to study the distribution networks of cocaine in order to provide intelligence related to its trafficking. An analytical methodology enabling through one single GC-MS injection the determination of the added cutting agents (adulterants and diluents), the cocaine purity and the chemical profile (based on the major and minor alkaloids) for each specimen was thus implemented and validated. The methodology was found to be efficient for the discrimination between specimens coming from the same source and specimens coming from different sources. The results highlighted the practical utility of the chemical profiling, especially for supporting the investigation through operational intelligence and improving the knowledge related to the cocaine trafficking through strategic intelligence.

Les interventions de la police scientifique suite à des cambriolages: quelle est la perception des lésés et y a-t-il lieu de s'en soucier?

Les cambriolages constituent une délinquence de masse et représentent à cet égard un problème de sécurité prégnant. Les organismes policiers y répondent notamment en faisant intervenir leurs services de police scientifique sur les lieux de cambriolages, dont les missions principales sont de constater l'infraction, de récolter les traces afin d'identifier les auteurs et de les dénoncer à la justice, ainsi que de contribuer au renseignement criminel. Ces objectifs traditionnels occultent toutefois une dimension pouvant s'avérer importante de ce type d'interventions de haut volume, à savoir la relation et la communication entre l'inspecteur de police scientifique et les lésés chez lesquels il intervient. On constate à ce sujet un manque de connaissances quant à la perception que les lésés ont des interventions de la police scientifique. En sont-ils satisfaits ? Les jugent-ils utiles ? S'inquiètent-ils des résultats obtenus et de la résolution de leur cambriolage ? S'estiment-ils suffisamment informés ou conseillés en matière de prévention ? Cette étude aborde ces questions au travers d'un sondage inédit entrepris auprès de 77 lésés de cambriolages chez lesquels le Service forensique de la Police neuchâteloise est intervenu. Les réponses des lésés indiquent qu'ils ont, dans l'ensemble, une très bonne opinion de l'intervention de la police scientifique et de ses différentes composantes. Parallèlement, il ressort que les 14 inspecteurs du Service forensique, également questionnés, projettent sur les lésés une opinion en partie plus pessimiste qu'elle ne l'est en réalité. L'étude permet ainsi d'identifier des points pour lesquels la communication doit être améliorée, par exemple en ce qui concerne les conseils en matière de prévention. L'article est ponctué par une proposition de modèle conceptuel qui étend les rôles et les missions traditionnellement attribués aux services de police scientifique et qui vise à intégrer la participation aux efforts de prévention, de proximité, de réassurance et de prise en charge des lésés.