Transmittance applications

R. Yabe. Near-infrared transmittance application for determining moisture content of surimi products. In Proc 2nd Inti NIRS Conf Tsukuba, Japan 190-195, 1989. 

The probe for this application contains two pairs of transducers (transmitters S and receivers E), see figure 7. 

In order to obtain a high signal-to-noise ratio sufficient acoustical power is necessary. For special applications a programmable pulser (transmitter) is required in order to optimize the frequency spectrum. 

In testing materials with high sound damping, the burst transmitter increases the signal-to-noise ratio to, typically, 12 dB. Typical applications honeycomb and concrete components, and air-coupled testing. 

For special applications such as air coupled testing a special programmable transmitter board was developed. This transmitter generates rectangular and burst signals, which increase the acoustical power in an optimized frequency range, and provides a superior signal-to-noise ratio. 

Glasses 7905, 7910, 7911, 7912, 7913, and 7917 foi special uv and k applications. Glass 1720 is available with improved uv transmittance (designated glass 9730). Glass 7760 is also available with special transmission suitable for sunlamps. 

Flow is an important measurement whose calibration presents some challenges. When a flow measurement device is used in applications such as custody transfer, provision is made to pass a known flow through the meter. However, such a provision is costly and is not available for most in-process flowmeters. Without such a provision, a true cahbration of the flow element itself is not possible. For orifice meters, calibration of the flowmeter normally involves cahbration of the differential pressure transmitter, and the orifice plate is usually only inspected for deformation, abrasion, and so on. Similarly, cahbration of a magnetic flowmeter normally involves cahbration of the voltage measurement circuitry, which is analogous to calibration of the differential pressure transmitter for an orifice meter. 

Pneumatic Controllers The pneumatic controller is an automatic controller that uses pneumatic pressure as a power source and generates a single pneumatic output pressure. The pneumatic controller is used in single-loop control applications and is often installed on the control valve or on an adjacent pipestand or wall in close proximity to the control valve and/or measurement transmitter. Pneumatic controllers are used in areas where it would be hazardous to use electronic equipment, in locations without power, in situations where maintenance personnel are more familiar with pneumatic controllers, or in applications where replacement with modern electronic controls has not been justified. 

One method that can be used to overcome most of the environment-induced problems is to use plastic tubing to shield the beam. This tubing can be placed between the transmitter and receiver of the optical-alignment fixture. It should be sized to permit transmission and reception of the light beam, but small enough to prevent distortion caused by atmospheric or environmental conditions. Typically, 2-inch, thin-wall tubing provides the protection required for most applications. 

They may be classified by their structure, as coin, cylindrical and pin types. Table 5, 6, 7 respectively show their specifications. Applications of Li -(CF)n batteries as power sources are spreading from professional and business uses, such as in wireless transmitters and integrated circuit (IC) memory preservation, to consumer uses in electronic watches, cameras, calculators, and the like. Pin-type batteries are used for illumination-type fishing floats with a light-emitting diode. Coin-type batteries, which have a stable packing insulation, separator, and electrolyte for high... 

A number of areas in which plastics are used in electrical and electronic design have been covered there are many more. Examples include fiber optics, computer hardware and software, radomes for radar transmitters, sound transmitters, and appliances. Reviewed were the basic use and behavior for plastics as an insulator or as a dielectric material and applying design parameters. The effect of field intensity, frequency, environmental effects, temperature, and time were reviewed as part of the design process. Several special applications for plastics based on intrinsic properties of plastics materials were also reviewed. 

Heat- and light-separation coatings (also known as hot and cold mirrors) are important applications that separate the hot (infrared) from the cold (visible) radiation. The principle is shown schematically inFig. 16.2. The transmittance of a cold mirror is shown in Fig. 16.3a. This mirror is coated with a dielectric film reflecting more than 90% of the... 

Figure 2.4 Noradrenergic inhibition of Ca " currents and transmitter release in sympathetic neurons and their processes, (a) Inhibition of currents through N-type Ca " channels by external application of noradrenaline (NA) or by over-expression of G-protein P y2 subunits, recorded from the soma and dendrite of a dissociated rat superior cervical sympathetic neuron. Currents were evoked by two successive 10 ms steps from —70 mV to OmV, separated by a prepulse to -1-90 mV. Note that the transient inhibition produced by NA (mediated by the G-protein Go) and the tonic inhibition produced by the G-protein Piy2 subunits were temporarily reversed by the -1-90 mV depolarisation. (Adapted from Fig. 4 in Delmas, P et al. (2000) Nat. Neurosci. 3 670-678. Reproduced with permission), (b) Inhibition of noradrenaline release from neurites of rat superior cervical sympathetic neurons by the 2-adrenoceptor stimulant UK-14,304, recorded amperometrically. Note that pretreatment with Pertussis toxin (PTX), which prevents coupling of the adrenoceptor to Gq, abolished inhibition. (Adapted from Fig. 3 in Koh, D-S and Hille, B (1997) Proc. Natl. Acad. Sci. USA 1506-1511. Reproduced with permission)...

J. Toft and O.M. Kvalheim, Eigenstructure tracking analysis for revealing noise patterns and local rank in instrumental profiles application to transmittance and absorbance IR spectroscopy. Chemom. Intell. Lab. Syst., 19 (1993) 65-73. 

The amplified signal from the transmitter is sent to the controller, which can be a computer or a little black box. There is not much we can say about the controller function now, except that it is likely a PID controller, or a software application with a similar interface. 

Transmittance. This was discussed in section 2.2.5 the application of the transmittance IR approach to the study of electroactive solution species is effectively limited to non-aqueous solvents. 

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