Conventional methods of measurement

The best anti-surge control is the simplest and most basic that will do the job. The most obvious parameter is minimum-flow measurement, or if there is a relatively steep pressure-flow characteristic, the differentia pressure may be used. The latter parameter allows for a much faster response system, as flow measurement response is generally slow however, the speed of response need only be fast enough to accept expected transients. One major problem with the conventional methods of measurement and control is the need to move the set point for initiation of the control signal away from the exact surge point to allow some safety factor for control response time and other parameters not directly included... 

The conventional method of measuring the amount of decomposition which has taken place is by the dimensionless fractional decomposition, a, which ranges from 0.00 for the pure reactant, to 1.00 signifying complete decomposition. On the assumption that both solid and gaseous products maintain a constant composition, a at any time during the decomposition may be measured directly from ... 

Fried foods quality is defined by their properties, such as moisture and oil contents, porosity, color, taste, and nutritional content (Dogan et al., 2005). Conventional methods of measuring these properties include physical (instrumental), chemical, and sensory methods (Qiao et al., 2007a). Some of these procedures are subjective, cumbersome, and time-consuming, and often require the destruction or modification of a product. During the past decade, a number of novel methods for determining food properties have been proposed, and some of them are presented below. 

Several techniques have been developed to measure the zeta potential, based on the principle of electrokinetics. In this entry, the conventional methods of measuring the zeta potential using the mechanisms of electrophoresis, streaming potential, and electroosmotic flow will be... 

Several techniques have been developed to measure the zeta potential, based on the principle of electrokinetics. In this entry, the conventional methods of measuring the zeta potential using the mechanisms of electrophoresis, streaming potential, and electroosmotic flow will be outlined first. Then, a novel method will be presented for simultaneously determining the zeta potentials of both the microchannel surfaces and the tracer particles by using the microscale particle image velocimetry (micro-PIV) technique. This method combines the theories of... 

Compared with conventional methods of measuring velocity distributions with mechanical selectors or with conventional time-of-flight tubes, this spectroscopic detection method has the following advantages ... 

The data presented here have excluded nematic polymer liquid crystals. These present particular difficulties for the conventional methods of measurement, which require well-aligned samples. A magnetic resonance technique has been developed which is particularly suited to the measurement of the elastic and viscous properties of liquid crystalline polyma s, and this technique and specimen results are described in Datarevicw 8.3 in this volume [40]. Thore have been some measurements on the precursors to polymers i.e. dimers and trimers (see Section C3), and these limited results do indicate the importance of molecular shape in determining the elastic properties. In particular, the extended even dimer has elastic constants almost twice those of the bent odd dimer. Thus in polymer liquid crystals, it is clear that the chain configuration will have a dramatic influence on the elastic properties. 

In general, the sensitivity of FIA is less than that for conventional methods of analysis for two principal reasons. First, as with chemical kinetic methods, measurements in FIA are made under nonequilibrium conditions when the signal has yet to reach its maximum value. Second, dispersion of the sample as it progresses through the system results in its dilution. As discussed earlier, however, the variables that influence sensitivity are known. As a result the FIA manifold can be designed to optimize the sensitivity of the analysis. 

Selectivity in FIA is often better than that for conventional methods of analysis. In many cases this is due to the kinetic nature of the measurement process, in which potential interferents may react more slowly than the analyte. Contamination from external sources also is less of a problem since reagents are stored in closed reservoirs and are pumped through a system of transport tubing that, except for waste lines, is closed to the environment. 

Porosity and surface area are routinely measured by nitrogen absorption-desorption, mercury intrusion, and low-angle X ray. The electron microscope (EM) provides direct visual evidence of pore size and pore-size distribution. Thus, a combination of EM and conventional methods of pore-size measurement should provide reliable information on the pore structure of polymers. 

A fairly recent method of measuring expl energy (power in our convention) depends on accurate determination of the expansion of an explosively-driven metal cylinder (Refs 7 8) Table 3... 

This example shows that the method discussed can deal with the difficulties frequently met in real situations. One of the products (D) was difficult to measure and another one (F) not accurately analyzed. So the balance could not close and conventional methods of determining stoichiometry via balancing could fail. The standard error in determination of species (C) was in the range of 6-14 % of the measured value in the first period of the experiment . Despite these difficulties, two simple reactions were found with stoichiometry that can adequately represent the reactions. The final representation of the chemical system is not unique but the final stoichiometric coefficients are within 10 % of the original ones. This indicates that the proposed methodology can yield reasonable approximations. 

A kinetic study requires the determination of the concentration (in mol dnr3) of at least one of the reactant or product as a function of time. In case of gaseous phase, in place of concentration, the partial pressure is determined. The method of analysis employed must be faster than the rate of reaction. The conventional methods of analysis can be applied to the reactions which have a half-life of at least a few minutes. The measurement of some physical property which is proportional to the concentration/partial pressure can also be taken for determination of the rate. In many cases of reactions in solution, it is necessary to take out aliquots from the reaction mixture at suitable intervals of time, arrest the reaction in aliquots by means of suitable means and then analyse the sample. Some conventional physical methods used to study the kinetics of slow reactions are described as follows. 

Many experimental techniques were used to examine polymerization kinetics and products of template polymerization. In kinetic measurements, many conventional methods of determination of monomer concentration were applied, very often UV spectrometry or bromometric titration. For many systems examined, bromometric titration gives results comparable with the results obtained by other methods. However, systems were found in which the method successful for blank reaction gives results incomparable with another analytical methods. Perhaps some specific reaction with the complex formed affects the analytical procedure." ... 

When conventional methods of manual optimisation are no longer sufficient, it is possible to use deconvolution software or fuzzy logic to deconvolute unresolved peaks into Gaussian components for which the area can be easily measured (see Fig. 1.12). 

Mass chromatography has several advantages (2) over conventional methods of molecular weight measurement such as cryoscopy, ebulli-ometry, vapor density, and osmometry. For example, these methods require a pure sample and are dependent on ideal solution behavior or extrapolation to infinite dilution. 

It is seen that, at short times, the contribution of the term a in the expression for V can be quite significant. But at long times, t 103s (such measurement times are typical of the conventional methods of determining G in radiation chemistry), in most cases, though not always, the condition V a, i.e. V" V is fulfilled. Thus, the values of V listed in Table 4 can be used to estimate the tunneling distances Rt... 

Like dichloromethane, the fluoro- analogue is weakly flammable, with flammability not revealed by many conventional tests. A new method of measurement is described [1]. The explosion properties with air of both difluoro- and chlorofluoro-methane have been studied [2]. 

Animal assays. When assessing the nature of a protein quality reduction, the conventional methods of protein quality measurement have certain limitations. For example, a reduced TD in an NPU assay is not necessarily the result of a reduced protein digestion. Obviously the same result will be obtained if the increase of fecal nitrogen is caused by an enhanced excretion of endogenous protein or if there is a fixation of metabolic nitrogen by the colonic micro-flora. 

For such types of measurements it is necessary to create, sustain and use certain conventional units which are not within the scope of the SI. Such units are realized on conventional scales, relying on reference materials (RMs), realizing the fixed point(s), and the standard specification or similar document, giving the method of measurement. Therefore, both should be strictly defined to ensure the compatibility and traceability of... 

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