Measuring devices

If a pressure measuring device were run inside the capillary, an oil gradient would be measured in the oil column. A pressure discontinuity would be apparent across the interface (the difference being the capillary pressure), and a water gradient would be measured below the interface. If the device also measured resistivity, a contact would be determined at this interface, and would be described as the oil-water contact (OWC). Note that if oil and water pressure measurements alone were used to construct a pressure-depth plot, and the gradient intercept technigue was used to determine an interface, it is the free water level which would be determined, not the OWC. 

This first part of the standard deals with the fundamental demands that are placed on the measuring devices to be used and on the procedures to be implemented toward a definition of the relevant parameters of the imaging system /6/. 

The System of accreditation is a mechanism that ensures official recognition that calibration or testing laboratory has right to perform testing of measuring devices, specific testing or specific types of testing. 

Apart from the development of imaging and force measurement devices, an important biophysico-chemical problem is... 

If very many measurements are made of the same variable a , they will not all give the same result indeed, if the measuring device is sufficiently sensitive, the surprising fact emerges that no two measurements are exactly the same. Many measurements of the same variable give a distribution of results Xi clustered about their arithmetic mean p. In practical work, the assumption is almost always made that the distribution is random and that the distribution is Gaussian (see below). 

A number of technically important viscosity-measuring devices may be thought of as variants of this basic apparatus. 

Handbook 44, Specifications, Tolerances, and Other Technical Requirements Tor Weighing and Measuring Devices, National Institute of Standards and Technology, Gaithersburg, Md., 1996. 

A constant temperature is required for close-tolerance measuring, gauging, machining, or grinding operations, to prevent expansion and contraction of machine parts, machined products, and measuring devices. In this instance a constant temperature is normally more important than the temperature level. Relative humidity is secondary in importance but should not go above 45% to minimise formation of a surface moisture film. 

There are five locations ia use for the taps used to couple the differential to the measurement device. These locations are depicted ia Figure 7. 

Important features of bulk milk tanks include a measuring device, generally a caUbrated rod or meter cleaning and sanitizing facdities and stirring with an appropriate agitator to cool and maintain cool milk temperatures. 

Another anomalous property of some nickel—iron aHoys, which are caHed constant-modulus aHoys, is a positive thermoelastic coefficient which occurs in aHoys having 27—43 wt % nickel. The elastic moduH in these aHoys increase with temperature. UsuaHy, and with additions of chromium, molybdenum, titanium, or aluminum, the constant-modulus aHoys are used in precision weighing machines, measuring devices, and osciHating mechanisms (see Weighing AND proportioning). 

Reactivity is measured by placing a standard quantity, 100 mL, of isopropyl alcohol in a 500- or 1000-mL Dewar flask equipped with a stirrer and a temperature-measuring device. The temperature of the alcohol is adjusted to 30°C. Thirty-six grams of the sample are added and the temperature is observed as a function of time from the addition until a maximum is reached. Reactivity is defined as the temperature rise divided by the time interval to reach this maximum. Other alcohols may also be used for measuring reactivity (30). 

Fig. 7. Instmment components of a control loop, where A = process measurement devices, in this case, pressure measurement B = transducer ...

To avoid maintenance problems, the location of pressure measurement devices must be carefully considered to protect against vibration, freezing, corrosion, temperature, overpressure, etc. For example, in the case of a hard-to-handle fluid, an inert gas is sometimes used to isolate the sensing device from direct contact with the fluid. 

In general, low level detection is masked by the noise level inherent in any measuring device. Electrochemical methods are susceptible to electrical interference from external sources, variations in reference electrode parameters resulting from aging or contamination, and interference from redox... 

Fig. 10. The Groth ZG 5 centrifuge. R, rotor R, stationary shaft T, Teflon seal K, K, chambers for gas scoops S, S2, scoops V, gas supply M, manometer Z, Z2, tapping points for enriched and depleted gas P, P2, vacuum chambers E, electromagnet for eddy current heating Tb, Tb2, temperature measuring devices K, cooling coil and D, D2, labyrinth seals.

The process and instrumentation (P I) diagram provides a graphical representation of the control configuration for the process. The P I diagrams illustrate the measurement devices that provide inputs to the control strategy, the actuators that will implement the results of the control calculations, and the function blocks that provide the control logic. 

The usual measuring device for feed flow is a magnetic flowmeter, which is a volumetric device whose output F must be multiplied by density p to produce mass flowMo- For most aqueous solutions which are fed to evaporators, the product of density and the function of solid content appearing above is linear with density ... 

Device A device is the smallest element of interest to batch logic. Examples of devices include measurement devices and actuators. 

Continuous mea.sui ements. An example of a continuous measurement is a level measurement device that determines the liquid level in a tank (in meters). 

The components of a typical continuous measurement device are as follows ... 

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