Basic principles of measurements

The promising use of various MALDI- and ESI-MS approaches in proteome research has accelerated many developments in the instrumental design and concepts of mass spectrometry. Novel MS techniques and intriguing combinations of existing instruments have emerged. Nonetheless, the basic principle of measuring the mass-to-charge ratios of analytes remains. 

The determination of ash in coal slurries uses the basic principle of measurement of those for solid coal. The extra problem is that the entrained air could seriously affect the accuracy of these devices. Various methods are used to compensate for this, such as pressurizing the system to collapse the air bubbles (ASHSCAN) or using a neutron attenuation measurement to correct for possible air entrainment (AMDEL). 

In Fig. 2, the basic principle of measurement of partial currents is shown. The current I consists of both electronic and ionic partial currents ... 

This reaction Eq. 15 is the basic principle of measurement of dissolved oxygen during the steel production [4] ... 

Basic Principles of Measurement of Inter cial Rheology... 

In modem electrical engineering, measurement of temperature can performed by various different methods, starting from a most basic bimetal temperature switches up to laser pre-celebrated semiconductor sensors with high accuracy (Boyes, 2010). The most basic principle of measuring temperature in industrial plants is the use of thermocouple probes by exploiting the thermoelectric effect in metals (called the Seebeck effect) that... 

Measurements and Audits. The enabling element of continuous improvement is measurement. An old rule of thumb says that increased accuracy in measuring an energy use ultimately yields a reduction in use equal to 10% of the increased closure of the balance. A basic principle of economics is that any thing that is free is used in excess, ie, an unmetered electrical use is bigger than expected by at least 10%. Metering of the cost elements at each unit in a chemical plant provides effective accountabhity. Measurements should be linked via computer software to production as weh as to weather to result in maximum feedback. 

The abundance of a trace element is often too small to be accurately quantihed using conventional analytical methods such as ion chromatography or mass spectrometry. It is possible, however, to precisely determine very low concentrations of a constituent by measuring its radioactive decay properties. In order to understand how U-Th series radionuclides can provide such low-level tracer information, a brief review of the basic principles of radioactive decay and the application of these radionuclides as geochronological tools is useful. " The U-Th decay series together consist of 36 radionuclides that are isotopes (same atomic number, Z, different atomic mass, M) of 10 distinct elements (Figure 1). Some of these are very short-lived (tj j 1 -nd are thus not directly useful as marine tracers. It is the other radioisotopes with half-lives greater than 1 day that are most useful and are the focus of this chapter. 

The basic principle of most colorimetric measurements consists in comparing under well-defined conditions the colour produced by the substance in unknown amount with the same colour produced by a known amount of the material being determined. The quantitative comparison of these two solutions may, in general, be carried out by one or more of six methods. It is not essential to prepare a series of standards with the spectrophotometer the molar absorption coefficient can be calculated from one measurement of the absorbance or... 

Quality control is intended to monitor and evaluate the performances of both food and human processes that contribute to food quality. The basic principle of this function is the control circle that involves (1) the taking of a process sample by the analysis or measuring unit, (2) determining whether process results meet set tolerances or limits, (3) judging the character and level of any discrepancy, and (4) application of corrective action to adjust the system to an acceptable level (Figure 7.1.1). A distinction is made between measuring and analysis, whereby the first involves direct measurements (e.g., pH, temperature) and the second involves taking samples, sample preparation, and actual analysis. ... 

The basic principle of every measurement of the Volta potential and generally of the investigations of voltaic cells too, in contrast to galvanic cells, may thus be presented for systems containing metal/solution (Fig. 2) and liquid/liquid interfaces (Fig. 3), respectively. This interface is created at the contact of aqueous and organic solutions (w and s, respectively) of electrolyte MX in the partition equilibrium. Of course, electrolyte MX, shown in Fig. 2 and other figures of this chapter, may be different in organic (s) and aqueous (w) phases. 

The pCOj electrode was first described in 1957 by Stow and later improved to its presently used form by Severinghaus The basic principle of operation relies on equilibration of COj with an aqueous solution. The change in pH in the aqueous solution associated with the equilibration due to carbonic acid formation (H2CO3) is measured and varies with log pCO2] It should be pointed out here that these measurements (and likewise for the pO electrode described below) give CO2 tension not concentration. To obtain concentration, Henry s Law of gas solubUity must be applied. However, for most medical and biological applications the knowledge of the gas tension is sufficient. 

The three historical approaches to certification mentioned above were recently expanded to identily seven modes that are used at NIST for value assignment for chemical composition (May et al. 2000). These seven modes and the resulting values are summarized in Table 3.13. The basic principles of value assignment remain unchanged however, these modes now provide a well-defined link between the process used for value assignment and the definition of the assigned value (i.e. certified, reference, or information value). The terms described above provide a clear indication of the level of confidence that NIST has in the accuracy of the assigned value. The definition of a certified value implies that NIST must be involved in the measurement process for the value to be classified as a NIST certified value (see modes 1-3 in Table 3.13). Thus, modes 4 and 7, which do not involve NIST measure-... 

According to the basic principle of quantum mechanics, any measurable property can be computed ab initio if the total wave function y/ describing the quantum eigenstate of the system is known, since it contains the complete... 

Powsncr, E.R. (1994) Basic principles of radioactivity and its measurement. In Tietz Textbook of Clinical Chemistry (C.A. Burtis, and E.R. Ashwood, eds.), pp. 256-282. Saunders, Pennsylvania, Philadelphia. 

The basic principle of solution calorimetry is simple. In one experiment the enthalpy of solution of, for example, LaA103(s) [32] is measured in a particular solvent. In order to convert this enthalpy of solution to an enthalpy of formation, a thermodynamic cycle, which gives the formation reaction... 

In the following, the basic principle of the flexible recipes is presented. To keep the explanations simple, we consider only one single type of end product that is produced from one single raw material on one resource at a specific location during a given period. Required are the maximum process throughput of the resource measured in tons of output per hour and the input of raw material and output of finished products, respectively. In many types of chemical mass production, raw material consumption depends on the utilization rate of the equipment employed. Hence, linear recipe functions can be derived, which indicate the input of raw material required to produce the desired amount of output. 

In Pharmaceutical and Clinical Calculations, second edition, Drs. Mansoor Khan and Indra Reddy have provided a contemporary resource that can help pharmacy students learn the basic principles of how to accurately interpret prescriptions and medication orders, measure, calculate and compound quality dosage forms. In the latter chapters, the student can learn multiple methods to accurately and safely dose patients. The computational methods to accomplish these ends are clearly presented, and the examples used to demonstrate the concepts are relevant to contemporary practice. Pharmacy students will... 

The use of so-called toners to improve the color has been described above. It should be remarked that all measures to overcome defects of a polymer caused by disregarding the basic principles of chemistry are rarely of durable success, because any additive will complicate or affect the polymeric system in an undesired way. 

Direct use of coal as a primary fuel is often the most efficient and economic method of utilizing this important energy resource. In many cases, however, certain undesirable properties of coal make direct utilization difficult. Coal is a solid and requires more effort to handle, measure and control than gases or liquids. Coal is usually contaminated with ash and other undesirable components and has widely variable chemical and physical properties. As a result, there is often a need to convert coal into more convenient and cleaner forms of energy and products. Before considering the basic principles of coal conversion, some important characteristics of fossil fuels will be reviewed. 

There are two widely used methods for measuring fluorescence lifetimes, the time-domain and frequency-domain or phase-modulation methods. The basic principles of time-domain fluorometry are described in Chapter 1, Vol.l of this series(34) and those of frequency-domain in Chapter 5, Vol. 1 of this series.<35) Good accounts of time-resolved measurements using these methods are also given elsewhere/36,37) It is common to represent intensity decays of varying complexity in terms of the multiexponential model... 

The basic principle of the method is simple. A cohort of patients with the disease in question is identified, and then a cohort of patients without the disease (usually two to three times as many) is matched with respect to a number of critical characteristics and used as the control group. Differences between the two groups with respect to exposure to the suspected causative agent are then measured. A major advantage is that uncommon or rare conditions are accessible to study, which is not the case for cohort studies or for computerised systems, where the total number of patients available is less than the several millions that might be needed. 

Basic principles of coating thickness measurement with quartz oscillators... 

Table 9.1 lists some of the theoretical relationships from Chapter 8, for example, and the difficulties in applying these relationships to field situations. Eventually, application to the field comes down to a creative use of laboratory and field measurements, with a good understanding of the results that theory has given us and to make sure that we do not violate some of the basic principles of the theoretical relationships. 

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