Corona-discharge CD is just the point at which the air breakdown begins to happen. This phenomenon is usually present when high voltage is applied between a needle and a metallic plate. The air molecules begin to ionizate, separation of their positive and negative charges occur and any minimum voltage increment produces a suddenly discharge between the electrodes. At this critical non-equilibrium point, some of the opposite separated charges are recombined and a light violet-blue emission is produced at the tip of the needle. The released energy can cause some kind of chemical transformation on the materials nearby. In this work we reported the composition of this emission captured from tip of the needle. We show the kind of change that this Corona-discharge produced on fabrics of cotton and linen. CD has been considered as one of the most probably effect that generate the image in the so called Turin Shroud. We present some image produced by controlled CD. Some discussion is given.
The most relevant parameters to control the quality of glass vials are the internal and external diameters of the mouth and the height of the rim. A low cost vision system based on a 486 PC, a frame grabber, 4 CCD cameras (768 X 512 pixels) and I/O device to control the production of vials, by adjusting the flames temperature in the moulding section of the machine, has been developed and tested. A 24 mandrel machine rotating at about 300 rpm with a production capability of about 4200 pieces/hour had to be monitored with an accuracy of +/- 0.02 mm in the measure of the mouth diameters and +/- 0.04 mm on the rim height. In order to minimize the time delay required for the machine temperature compensation, the measurements had to be taken during the forming process. The system must be fast enough to follow the process, able to take into account the temperature variation of different classes of vials and far enough from the high temperature of the flames. A direct calibration procedure, using a reference vial, and a pyrometer to check the temperature range was derived. A long focus lens coupled with a bellow to put the system away from the flames was adopted. The algorithm implemented for the measurements and the machine temperature control is presented.
This paper deals with some improvements on the accuracy of the laboratory model, presented in a previous work, for the simulation of the attitude control and pointing of an optical instrument connected to the Space Station, or other space facility, via a tether (2 to 10 Km long), mounted on a platform. The bidimensional model of this system was realized using a small platform equipped with a DC servo-motor and a screw bearing, floating with a small inclination angle, on an air table, and connected, like a pendulum, through a tether, to a second servo-motor on the wall. In the previous work the attitude control was based on the tracking of two points fixed on the model of the platform with one CCD camera and moving the attachment point on it. The new experimental apparatus, based on two CCD cameras, an optical system of mirrors and a He-Ne laser beam, has been assembled in order to better simulate the control system for a telescope mounted on the platform. The tracking is realized via a computer based vision system which acquires and locks a laser spot projected onto a screen representing the field of view of the telescope. The control loop has been optimized taking into account the disturbances produced by the simulation of the effect of the tether dynamics by means of a second motor which moves the wall tether end with a proper law, and reproducing the slewing manoeuvre effect of the telescope, on the dynamics of the system.
A study has been conducted about attitude control and pointing of an optical instrument (a Schmidt-type telescope) connected to the space station via a tether 2 to 10 km long, mounted on a platform. The tether plays a multifunctional role, including elastic suspension and data and power transmission. It will insulate the platform from dynamic noise, light, and other pollution from the space station. Furthermore, stabilization and active attitude control will be achieved by moving the attachment point of the tether with respect to the platform itself. A bi- dimensional model of this system has been realized and tested in the laboratory. The measurement and control concept that works on the basis of a computer vision system is discussed. The system is used to stabilize a platform floating on an air table attached to a fixed point through a tether, via a closed loop position control circuit. This is achieved through a CCD camera (768 X 512 pixels), an image processing software, and a dc motor with encoder which controls the attitude of the platform moving its attachment point. The tracking function is realized via a multiple windows technique using an algorithm based on the linearized equations of motion of the platform. The performance of the overall system is presented. An analysis of system characteristics with respect to a real application is carried out. In particular, the possibility of achieving stabilization and active attitude control of such a system by moving the attach point of the tether has been investigated.
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