Two channel

Usually all the flaw detectors in service have two channels to detect defects of a rope the LMA and LF channels. The inspection information is recorded by a chart recorder or by a tape recorder. 

These two transducer pairs are activated alternating. For this purpose an ultrasonic instrument is combined with a two channel multiplexer. Figure 8 presents a modified standard instrument USN52 which also implies a modified software. This system performs four measurements per second - alternating the velocity and the thickness are determined. The probe can be scanned over the surface and in every position both, the velocity and the wall thickness are indicated Using the serial interface of the instrument finally a two-dimensional map of velocity or thickness can be generated. 

Fig. 8 Ultrasonic instrument USN52 with a two channel multiplexer...

The four channel scanning system showed stable measurements up to 250 m/min drawing speed. At 300-350 m/min some measurements were unstable on two channels. At drawing velocities over 350 m/min measurements were unstable on all four channels. The four traces are better identified in colors on the computer screen than in this grey tone figure. 

Figure 28.19(c) Reactance of channel busbars, two channels per phase in box form, single-phase or three-phase, at 50 Hz... 

The simplest type of shell-and-tube heat exchanger is shown in Eigure 3-1. The essential parts are a shell (1), equipped with two nozzles and having tube sheets (2) at both ends, which also serve as flanges for the attachment of the two channels or beads ( 3) and their respective channel covers (4). The tubes are expanded into both tube sheets and are equipped w nil transverse baffles (5) on the shell side for support. The calculation of the effective heat transfer surface is based on the distance between the inside faces of the tube sheets instead of the overall tube length. 

In laminar flow, a processed material divides at the leading edge of each element and follows the channels created by the element shape. At each succeeding element the two channels are further divided, resulting in an exponential increase in stratification. The number of striations produced is 2 where n is the number of elements. 

Adler and Axelrod,58 in their two-channel spectrograph, have taken the ultimate step in this direction by measuring the two intensities simultaneously. We may take for granted that the proper use of-an internal standard can eliminate the effect of different variations in equipment in different cases. It follows that care may be relaxed in connection with variations thus eliminated for example, approximate voltage regulation suffices for an x-ray source used to excite both analytical lines when these are measured simultaneously. 

If we assume negative exponential service distribution for each of two channels with parameters and /n2 respectively, the general method of solution proceeds essentially as before except that one is faced with the determination of conditional probabilities P1(1,0, ) and Pi(0,U)i which respectively give the probability that one unit is in the system and it is in service in the first channel at time t and the probability that one unit is in the system and it is in service in the second channel at time t. 

Note that if = 2 = /x, the above system reduces to that of the two-channel case with identical exponential service. 

Another example is found in the scheme shown in Eqs. (4-50) to (4-52). The rate law, Eq. (4-54), contains two terms, consistent with an intermediate that branches along two channels. The same scheme, but with the first step (formation of the intermediate) rate-controlling, would not reveal this detail. The kinetics tells about what happens in the rate-controlling step, and sometimes prior to it, but not afterward. 

A patented Dow-designed specimen bar magazine with a capacity of 125 bars makes the specimens available to the robotic arm. Specimens are stacked vertically, with their end tabs constrained by two channels so that only vertical motion is possible. A slot in the base of each channel allows the robot to pull specimens, one at a time, from the bottom of the stack. Once removed from the channels, the bars are dropped down a pair of circular slides which... 

A serious problem associated with quadrature detection is that we rely on the cancellation of unwanted components from two signals that have been detected through different parts of the hardware. This cancellation works properly only if the signals from the two channels are exactly equal and their phases differ from each other by exactly 90°. Since this is practically impossible with absolute efficiency, some so-called image peaks occasionally appear in the center of the spectrum. How can you differentiate between genuine signals and image peaks that arise as artifacts of quadrature detection ... 

CYCLOPS A four-step phase cycle that corrects dc imbalance in the two channels of a quadrature detector system. 

Quadrature images Any imbalances between the two channels of a quadrature detection system cause ghost peaks, which appear as symmetrically located artifact peaks on opposite sides of the spectrometer frequency. They can be eliminated by an appropriate phase-cycling procedure, e.g., CYCLOPS. 

These experiments use the product state distribution technique to allow a qualitative characterization of the competition between multiple electronic states. In contrast to the pathway competition in the molecular channel of formaldehyde (Section V.D), where the correlated product state distributions delineate the two channels quite cleanly, it will likely more often be the case that the product state distribution method allows only qualitative separation, due to overlapping distributions. Nevertheless, such experiments provide critical insight into pathway competition. 

Figure 2.31 Characteristic temperature profiles in a counter-current micro heat exchanger for a very low (left), intermediate (middle) and very high (right) thermal conductivity of the wall material and equal volume flows inside the two channels, reproduced from [125],...

GP 4] [R 11] For methanol oxidation over sputtered silver catalyst, conversion is higher when using micro channels of smaller diameter (8.5 vol.-% methanol balance oxygen 510 °C 4—27 ms sHghfly > 1 atm) [72]. For two channels of the same width, but different depths (70 pm, 130 pm), concentration differences of nearly 10% at the same residence time were detected, all other parameters being equal. 

On this chip, two sets of two channels each branch in a T-configuration yielding eight channels [23, 24]. The latter are guided so that they merge to four channels in which the reactions are carried out (Figure 4.10). These channels comprise the full set of all 2 X 2 combinations of the reactants. 

The polymer chips comprise two feed micro channels which are connected in a Y-type flow configuration to one elongated micro channel which is folded multiple times for compact design [29]. At the end of this channel a split into two channels is made, again by a Y-type flow configuration. The two-channel flow configuration serves for preparing water-oil parallel (bi-laminated) streams. 

This reactor is based on two parallel micro channels that are separated by a wall. In front of the micro-channel section, one outlet hole is placed for liquid feed, followed by two holes for gas feed [13,14]. The liquid feed enters in line with the wall long axis, while the gas feeds have the position of the two channels. Consequently, the liquid flow has to split. 

This micro-chip reactor comprises a liquid inlet port which splits into two channels of equal passage [21]. These split channels merge with a third channel, which is connected to a second port for gas feed, in such way that the two liquid streams encompass the gas stream. This triple-stream feed section is followed by a long serpentine channel passage which ends in a third outlet port (Figure 5.11). 

It may be useful to assume that we know the equation of equilibrium for a fluid and demonstrate how a model of two channels allows us to evaluate the flattening of earth. First, consider the channel B, where we have... 

Figure 9. Schematic diagram showing a second-generation MC-ICPMS instrament (ThermoFinnigan Neptune). This instrument utilizes double-focusing and is equipped with a motorized multiple-Faraday collector block with two channels that can be operated in high-resolution mode. Optional multiple-ion counting channels are also available for the simultaneous measurement of low-intensity ion beams. [Used with permission of Thermo Finnigan.]...

---