Readout

The two most common pH readout displays are analog and digital. Each has advantages, and the selection of the type of readout should be based on which of the advantages best suits the application. 

The digital display has elements of simplicity and exactness that are not found on a scale and needle readout. The exact pH value is clearly displayed without need of interpretation. The pH value is always in expanded form reading to a hundreth or a thousandth of a pH unit without changing modes. The exact pH value is easily recorded on paper tape by connecting the BCD (binary coded decimal) output from a digital pH meter to a printer. 

These advantages would be particularly useful where numerous pH measurements are being taken with a requirement for reliable values over a wide pH range. 

The rate of pH change can be more easily interpreted on an analog meter than on the digital display. The needle travel per 

The pH meter recorder output is another method of obtaining expanded readability, permanent record, response time, or pH rate changes. Although measurement accuracy is not increased, the readability of the pH displayed can be expanded on a recorder. 

---

There is only one method available that allows the study of the vertical and lateral relationship of the different rock types of a reservoir on a scale of 1 1. This is the study of outcrops. These are areas like quarries, readouts, cliffs, mines, etc., which consist of a sequence known to be a reservoir in the vicinity or the lateral equivalent thereof. Detailed investigation of a suitable outcrop can often be used as a predictive tool to model ... 

Alternatively, gas chromatography may be used Fig. XVII-5 shows a schematic readout of the thermal conductivity detector, the areas under the peaks giving the amount adsorbed or desorbed. 

Figure Bl.14.1. Spin warp spin-echo imaging pulse sequence. A spin echo is refocused by a non-selective 180° pulse. A slice is selected perpendicular to the z-direction. To frequency-encode the v-coordinate the echo SE is acquired in the presence of the readout gradient. Phase-encoding of the > -dimension is achieved by incrementmg the gradient pulse G...

Figure Bl.14.2. Gradient-recalled echo pulse sequence. The echo is generated by deliberately dephasing and refocusing transverse magnetization with the readout gradient. A slice is selected in the z-direction and v- and y-dimension are frequency and phase encoded, respectively.

Personal Errors Finally, analytical work is always subject to a variety of personal errors, which can include the ability to see a change in the color of an indicator used to signal the end point of a titration biases, such as consistently overestimating or underestimating the value on an instrument s readout scale failing to calibrate glassware and instrumentation and misinterpreting procedural directions. Personal errors can be minimized with proper care. 

No contact with the material, no moving parts to wear out or corrode Unaffected by changes in the tension or stiffness of the conveyor belt Direct readout and adaptabiUty to modem controls... 

Measurement Requirements. Any analysis of measurement requirements must begin with consideration of the particular accuracy, repeatabihty, and range needed. Depending on the appHcation, other measurement considerations might be the speed of system response and the pressure drop across the flow meter. For control appHcations repeatabihty may be the principal criterion conversely for critical measurements, the total installed system accuracy should be considered. This latter includes the accuracy of the flow meter and associated readout devices as well as the effects of piping, temperature, pressure, and fluid density. The accuracy of the system may also relate to the required measurement range. 

Most laboratory and shop-use Rockwell hardness testers are nonportable, lever operated, deadweight machines. Newer versions have digital readouts rather than the traditional analogue dial. Some designs of Rockwell testers employ a spring-loading system instead of deadweights. 

Portable hand-held direct reading Rockwell testers have been developed and are in use, as are numerous C clamp configurations, all intended for field or shop use. The newest computerized digital readout Rockwell tester provides the ultimate in portabiUty at the cost of some loss of sensitivity due to the very light loads used. 

Fig. 5. Uniform plane wave grating where (a) is the recording, and (b) the readout.

In addition, most devices provide operator control of settings for temperature and/or response slope, isopotential point, zero or standardization, and function (pH, mV, or monovalent—bivalent cation—anion). Microprocessors are incorporated in advanced-design meters to faciHtate caHbration, calculation of measurement parameters, and automatic temperature compensation. Furthermore, pH meters are provided with output connectors for continuous readout via a strip-chart recorder and often with binary-coded decimal output for computer interconnections or connection to a printer. Although the accuracy of the measurement is not increased by the use of a recorder, the readabiHty of the displayed pH (on analogue models) can be expanded, and recording provides a permanent record and also information on response and equiHbrium times during measurement (5). 

From the write and read process sketched so far, some requirements for MO media can be derived (/) a high perpendicular, uniaxial magnetic anisotropy K in order to enable readout with the polar Kerr effect (2) a magnetoopticady active layer with a sufficient figure of merit R 0- where R is the reflectivity and the Kerr angle (T) a Curie temperature between 400 and 600 K, the lower limit to enable stable domains at room temperature and the upper limit because of the limited laser power for writing. 

In Reference 146 three methods for playback of data are presented, which are superior to the usual method based on the contrast in light scattering readout of dichroism, perpendicular readout mode, and readout of birefringence. Some critical comments also are given about global or selective erasure of data. 

Eig. 18. Microbolometer (a) array portion showing pixels on a 50-pm pitch. Each pixel is coimected to a readout amplifier in the supporting siUcon IC chip, (b) Detector having a 35 x 40 pm active area. The serpentine arms give excellent thermal isolation and the low mass results in a 10-ms response time, ideal... 

---