Sensor assembly

A typical sensor structure is displayed in Fig. 11.3. The sensing film is deposited on top of a substrate between the electrodes. The heater is 

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Intelligent transmitters have two major components (1) a sensor module which comprises the process connections and sensor assembly, and (2) a two-compartment electronics housing with a terminal block and an electronics module that contains signal conditioning circuits and a microprocessor. Figure 6.9 illustrates how the primary output signal is compensated for errors caused in pressure-sensor temperature. An internal sensor measures the temperature of the pressure sensor. This measurement is fed into the microprocessor where the primary measurement signal is appropriately corrected. This temperature measurement is also transmitted to receivers over the communications network. 

In order to make a FPI chemical sensor, the FP cavity needs to be made accessible by the analyte molecules. One way to achieve this is to use a holey sleeve to host the cavity. Xiao et al.7 reported such a fiber FPI gas sensor formed by bonding two endface-polished fibers in a holey sleeve using epoxy. The holey sleeve allows gas to freely enter and leave the cavity. A resolution of 10 5 was estimated in monitoring the changes in the refractive index caused by varying the gas composition. However, the sensor assembly was complicated and required the use of epoxy. In addition, the various components used in sensor construction were made of different materials. As a result, the device had a strong dependence on temperature. 

Figure 1.6 Schematic of the main stages of sensor assembly and functioning, demonstrated by an immunoglobulin test. (Reprinted with permission from Ref [28]. 1999 American Chemical Society.)...

Figure 14.4 Function and properties of a QD FRET-based nanosensor. Generalized QD bioconjugate nanosensor schematic. Each QD is surrounded by an average of —10—15 protein molecules. Formation of QD-protein-analogue assembly results in quenching of the QD emission. Adding preferred analyte to the solution displaces dye-labeled analogue from the sensor assembly, resulting in an increase in direct QD emission.

Kissinger [130] carried out similar experiments following lactate changes observed in a rat subcutaneous microdialysate upon an intraperitoneal injection of lactate. The half-life of the sensor, assembled by coating the enzyme lactate oxidase (LOD) on a glassy carbon electrode with an Os-redox polymer and a Nafion overcoating, was about 24 h. 

Solvent-resistant polymers are attractive for a variety of microanalytical applications. For chemical sensing, solvent-resistant polymers are important as supports for deposition of solvent-based polymeric sensing formulations.1 Otherwise, a solvent that is used for the preparation of the sensor formulation can attack a plastic substrate of choice forcing the use of either less attractive substrate materials or the use of a complicated sensor-assembly process.2 3 Solvent-resistant polymers also attract interest for microfluidic applications as an alternative to glass and silicon.43 Examples of solvent-resistant polymeric microfluidic systems include those for organic-phase synthesis,6 polymer synthesis,7 studies of polymeric and colloidal... 

The second, well-known use of stabilized zirconia is in oxygen sensors. These types of devices make use of the very high ionic conductivity of Y203- or CaO-doped cubic zirconia. The sensor assembly consists of a zirconia tube with one end closed. The inside of this tube is exposed to air and the outside is exposed to the gas that requires measurement of oxygen levels. When there is a difference in oxygen partial pressure between the inside and outside, oxygen is transported across the ceramic tube. This transport results in a measurable voltage. 

Fig. 7.13.9 and Fig. 7.13.10 show a light sensor assembly photographs and angular responses for both the solar sensor and the twilight sensor. The sensor is set to reach its maximum output when the sun is at an elevation about 40°, which is when the driver feels hottest. 

We developed a submersible electrode assembly, connected to a 50 ft (24 m) long shielded cable (via environmentally-sealed rubber connectors), for the real-time in-situ monitoring of the TNT explosive in natural water [10]. Such sensor assembly consists of the carbon-fibre, silver, and platinum working, reference, and counter electrodes, respectively, and operates in the rapid square-wave voltammetric mode. Such a remote/submersible probe circumvents the need for solution pumping and offer greater simplification and miniaturization. The facile reduction of the nitro moiety allowed convenient and rapid square-wave voltammetric measurements of ppm levels of TNT. Lower (ppb) concentrations have been detected using a... 

Many assembly tasks are performed manually, but high-volume assembly tasks are often performed by special-purpose machines that form an automated assembly line or a semi-automated assembly line. With a multi-sensor assembly station, the assembly task can be accomplished with high accuracy, repeatability, and efficiency. 

Sensor (Assembly), Table 1 Physical sensor effects ... 

Sensor (Assembly), Fig. 6 Fiber optics with total internal reflection... 

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