High measuring devices

Two-fluid U tube (Fig. 10-14). This is a highly sensitive device for measuring small gas heads. Let A be the cross-sectional area of each of the resei voirs and a that of the tube forming the U let Pi be... 

Once these traverse points have been determined, velocity measurements are made to determine gas flow. The stack-gas velocity is usually determined by means of a pitot tube and differential-pressure gauge. When velocities are very low (less than 3 m/s [10 ft/s]) and when great accuracy is not required, an anemometer may be used. For gases moving in small pipes at relatively high velocities or pressures, orifice-disk meters or venturi meters may be used. These are valuable as continuous or permanent measuring devices. 

Systematic error, as stated above, can be eliminated— not totally, but usually to a sufficient degree. This elimination process is called calibration. Calibration is simply a procedure where the result of measurement recorded by an instrument is compared with the measurement result of a standard. A standard is a measuring device intended to define, to represent physically, to conserve, or to reproduce the unit of measurement in order to transmit it to other measuring instruments by comparison. There are several categories of standards, but, simplifying a little, a standard is an instrument with a very high accuracy and can for that reason be... 

Any obstruction inserted into a duct or pipe that creates a measurable pressure difference can be used as a flow meter. The three basic standardized flow measurement devices presented above are perhaps more suitable for laboratory work than installation as permanent ductwork instruments in ventilation applications. They are sensitive to flow disturbances, relatively expensive, require considerable space, and have a narrow measurement range and a high permanent pressure loss. For these reasons, numerous attempts have been made to develop instruments without these drawbacks. Some of them, like the... 

Not a solid-state measurement device but an optical probe of high-intensity laser light is introduced into the fluid under investigation, avoiding disturbance on the flow field. 

One day the temperature-measuring device gave a false indication of high temperature. The air valve closed, and the drain valve opened. The temperature indication fell, perhaps because the reactor was now empty. The drain valve stayed open, but the air valve reopened, and a flammable mixture was formed in the reactor. Fortunately it did not ignite. 

Counter, Geiger-Mueller (GM counter)—Highly sensitive, gas-filled radiation-measuring device to detect (count) individual photons or particulate radiation. 

We hope that, given this work, we will have constructed a relatively inexpensive radiocarbon and radioberyllium measurement device that is capable of making measurements at high accuracy on very small samples. 

Measurements can contain any of several types of errors (1) small random errors, (2) systematic biases and drift, or (3) gross errors. Small random errors are zero-mean and are often assumed to be normally distributed (Gaussian). Systematic biases occur when measurement devices provide consistently erroneous values, either high or low. In this case, the expected value of e is not zero. Bias may arise from sources such as incorrect calibration of the measurement device, sensor degradation, damage to the electronics, and so on. The third type of measurement... 

In order to effectively utilize the stoichiometry of the reaction involved in a titration, both the titrant and the substance titrated need to be measured exactly. The reason is that one is the known quantity, and the other is the unknown quantity in the stoichiometry calculation. The buret is an accurate (if carefully calibrated) and relatively high-precision device because it is long and narrow. If a meniscus is read in a narrow graduated tube, it can be read with higher precision (more significant figures) than in a wider tube. Thus a buret provides the required precise measurement of the titrant. 

Resonant cavities are well-known, highly sensitive devices that have been used to make measurements of fundamental properties of matter in all its phases (Hong, 1974). A resonant cavity can be considered to be multiple inductor capacitor resistance... 

Poten- Potential" Pofentiometer - a high-resistance device for measuring potential A potentiometiic titration is a titration in which the end point is indicated by following the potential... 

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