Sensor front

A MEMS based plate array/front-end collection system (being developed independently by NRL as a universal small sensor front-end collection systems referred to as CASPAR). 

Figure 19 Proximity coil sensor front and side views.

Piezoelectric cavity pressure sensors are suitable for direct use in the cavity due to their physical properties. They are usually installed flush with the mold wall and can be adjusted to the surface by spark erosion or grinding of the sensor front. If installed correctly while maintaining the required drilling tolerances, an error-free measurement of the cavity pressure can be assumed. 

If the sensor bore does not correspond to the required tolerances, the sensor front touches the sensor bore in many cases, and the sensor loses its sensitivity. In technical language, this effect is called force shunt and can cause measurement errors of up to 30%. For this reason, cavity pressure sensors have recently developed that are initially built precisely into a sleeve and then calibrated in a second step [1]. The actual sensor is thus protected during installation, and measurement errors through the installation are excluded (PRIASAFE principle). The determined sensitivity is eventually stored in the sensor body itself as a code, so that no adjustments in the subsequent electronics in the industrial use have to be made [2]. The optimal measuring ranges are determined automatically as soon as the sensor is connected to the electronics (PRIASED principle). 

Depending on requirement, today, cavity pressure sensors are available with different dimensions, where not only the diameter of the sensor front but also the size of the sensor body plays an important role during the installation. Basically, the size of cavity pressure sensors should only be chosen as small as necessary, both to keep the installation costs to a minimum and to keep the required tolerances as simple as possible. 

While the cooling phase lasts until the mold opens, the time at which the cavity pressure again reaches atmospheric pressure is of great importance. At this moment, the plastic is released from the sensor front, and the shrinkage of the molded part starts. This time is not only significant for explaining the p-V-T-diagram but is also used in practical situations. 

The special design of the Latham bowl allows for a specific blood cell separation known as SURGE. This technique makes use of the principle of critical velocity. The Latham bowl is filled until the huffy coat, ie, layer of platelets and white cells, moves in front of the bowl optics. At this point the machine starts to recirculate plasma through the bowl at increasing rates. The smallest particles, ie, platelets, ate the first to leave the bowl. Their high number causes the effluent line to turn foggy. The optical density of the fluid in the effluent line is monitored by the line sensor. A special algorithm then determines when to open and close the appropriate valves, as well as the optimum recirculation rate. 

Since driver s-side airbags were made mandatory in 1984, it is estimated that they have saved thousands of lives (Figure A). The way they work is relatively simple. A mechanical sensor in the front of the vehicle is set off by any sudden impact equivalent to hitting a brick wall at 10 mph. The sensor sends an electrical signal to a gas generator attached to the airbag. 

FIGURE 6-7 Schematic representation of a disposable glucose sensor strip. (Reproduced with permission front reference 13.)... 

Figure 9. The Shack-Hartmann sensor with (a) a planar wavefront and (b) an aberrated wave-front. The dashed lines are the perpendicular bisectors of the lenslets.

Lane, R.G., Tallon, M., 1992, Wave-front reconstruction using a Shack-Hartmann sensor, JOSA.A 31, 6902... 

When NOj levels are measured electrochemicaUy, NO and NO2 can lead to opposing signals because NO is oxidized and NO2 tends to be reduced. Moreover, it is preferred to obtain a total NO, measurement instead of only one of the constituents. The latter can be achieved by catalytically equilibrating the feed with oxygen before contact with the sensor by coating an active zeolite layer on top or placing a active catalyst bed in front of the sensor. Both approaches have been demonstrated successfully with a Pt-Y zeohte as active catalyst [74, 75]. The additional advantage of the filter bed is a reduction in the cross-sensitivity with CO due to CO oxidation above 673 K. 

Additionally, NO is reduced by H2 and by hydrocarbons. To enable the three reactions to proceed simultaneously - notice that the two first are oxidation reactions while the last is a reduction - the composition of the exhaust gas needs to be properly adjusted to an air-to-fuel ratio of 14.7 (Fig. 10.1). At higher oxygen content, the CO oxidation reaction consumes too much CO and hence NO conversion fails. If however, the oxygen content is too low, all of the NO is converted, but hydrocarbons and CO are not completely oxidized. An oxygen sensor (l-probe) is mounted in front of the catalyst to ensure the proper balance of fuel and air via a microprocessor-controlled injection system. 

Fig. 3.15 Left External view of the MIMOS II sensor head (SH) with pyramid structure and contact ring assembly In front of the Instrument detector system. The diameter of the one Euro coin is 23 mm the outer diameter of the contact-ring is 30 mm, the inner diameter is 16 mm defining the field of view of the Instrument. Right. Mimos II SH (without contact plate assembly) with dust cover taken off to show the SH Interior. At the front, the end of the cylindrical collimator (with 4.5 mm diameter bore hole) Is surrounded by the four SI-PIN detectors that detect the radiation re-emltted by the sample. The metal case of the upper detector is opened to show its associated electronics. The electronics for all four detectors Is the same. The Mossbauer drive is inside (in the center) of this arrangement (see also Fig. 3.16), and the reference channel is located on the back side In the metal box shown In the photograph...

Fig. 8.29 The flight unit of the MEMOS II Mossbauer spectrometer sensor head (for the rover Opportunity), with the circular contact plate assembly (front side). The circular opening in the contact plate has a diameter of 15 mm, defining the field of view of the instrument...

The procedures of experiments were the following [15, 26]. After deposition of a specific quantity of silver on substrate the heating of a tray with silver was turned off, the shutter 7 was opened and the sensor was positioned opposite to the substrate in such a manner that the surface of the sensor was parallel to the surface of substrate. In these experiments we detected an irreversible donor signal of the sensor which can be related to adsorption silver atoms on the sensor made of a zinc oxide film. It is known [27] that silver atoms are donors of electrons. Note that the signals of the sensor were observed only when the sensor was positioned in front of a substrate. There were no signals detected in any other arrangement between sensor and substrate. 

X. Zhang, Real time and in vivo monitoring of nitric oxide by electrochemical sensors - from dream to reality. Front. Biosci. 9, 3434-3446 (2004). 

The containers for water softener and clarifiers are situated in the door of the dishwasher. The reed sensor is mounted next to the plastic casing that contains a magnet in a protective foam housing, floating on the liquid. When the level drops to a certain point, the floater activates the reed sensor, which in turn directly operates an indicator light on the front panel. The operator of the dishwasher is then alerted that softeners and/or clarifiers need to be refilled. 

To replace the old-fashioned eye-control method of detecting the level of the liquid, appliance manufacturers now use reed sensors to show when the container for Jet-Dry needs refilling. The reed sensor is mounted underneath, or next to, the liquid container. A floater with an internal permanent magnet is placed in the container and floats on the liquid. If its level falls to a minimum, the floater activates the reed sensor which, in turn, activates a light on the front control panel of the dishwasher, signaling the need to refill the Jet-Dry container. 

An optical flame sensor installed at the beginning of the pipeline is the most suitable device for such an isolation system, since the propagating flame from the explosion has to be detected and extinguished. Pressure detectors alone are, in principle, not suited to the case on hand because there is no distinct separation between the pressure and flame fronts for explosion in pipelines. Optical ir sensors that have a relatively low sensitivity to daylight are normally chosen and have proved themselves amply in industrial practice. Therefore, daylight into the pipe in the vicinity of the sensor must be avoided. It is necessary to flush the optical lens with gas (e.g., nitrogen, air) to keep it dust-free. 

Fig. 36.1 An odour station being visited by a U. caudimaculatus, showing the odour source in cage at front of picture and IR sensors on each side... 

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