Moisture, analysis Subject

The impurities on the surface are contained in the resulting water droplet or moisture film, and are collected in situ for further investigation by scanning the surface with an auxiliary water droplet (e.g., 50 pi). The VPD residue is allowed to dry in the center of the wafer and subjected to TXRF analysis. A schematic of a VPD reactor is shown in F ure 3. 

A laminate can be subjected to thermal, moisture, and mechanical loads with the objective of surviving those loads. A method of strength analysis is required to determine either (1) the maximum loads a given laminate can withstand or (2) the laminate characteristics necessary to withstand a given load. The maximum loads problem is, of course, an analysis situation, and the laminate characteristics problem is a design situation that will be discussed in Chapter 7. 

Though the literature is replete with methods of measuring the moisture content, truly accurate as well as practical methods are virtually nonexistent in the food field. The situation is well illustrated in what is probably the best compendium on this subject, the Official and Tentative Methods of Analysis of the Association of Official Agricultural Chemists (2). It becomes apparent from an examination of this volume that the stress is laid not so much on accuracy as on reproducibility and practicability of a method. Though these last two factors are for the most part the only ones of importance in the control of processing procedures and in standardization of products of commerce, the factor of accuracy is, nevertheless, of extreme importance to the research worker who endeavors to establish broad quantitative generalizations for the conditions that govern the stability of foods. 

The standard test method for proximate analysis (ASTM D-3172) covers the methods of analysis associated with the proximate analysis of coal and coke and is, in fact, a combination of the determination of each of three of the properties and calculation of a fourth. Moisture, volatile matter, and ash are all determined by subjecting the coal to prescribed temperature levels for prescribed time intervals. The losses of weight are, by stipulation, due to loss of moisture and, at the higher temperature, loss of volatile matter. The residue remaining after ignition at the final temperature is called ash. Fixed carbon is the difference of these three values summed and subtracted from 100. In low-volatile materials such as coke and anthracite coal, the fixed-carbon value equates approximately to the elemental carbon content of the sample. 

Individuals with sensitive skin often have associated dry skin. In a recent study of subjects with sensitive hands, no difference in skin hydration was seen macroscopically between normal subjects and sensitive hand subjects (who had self-perceived dry skin). However, measurement with the corneometer confirmed reduced skin surface moisture in the group with sensitive hands, and D-squame analysis showed greater loss of cohesiveness between corneocytes harvested from the... 

Spectral analysis techniques to study the behavior of pol3rmers subjected to dynamic mechanical loads and/or deformation is called Fourier Transform Mechanical Analysis (FTMA). FTMA measures the complex moduli over a range of frequencies in one test by exciting the sample by a random signal (band limited white noise) (13.14). FTMA overcomes or circumvents problems inherent in other test methods because it measures dynamic mechanical properties over a wide range of frequency with minimal temperature and moisture changes within the sample. 

The first batch of sodium silicofluoride was sampled and subjected to particle-size analysis (see Section 4.3) with the following results 3% retained on 100-mesh sieve, 9% passes through the 325-mesh sieve. The moisture content was 0.05%. Applying the feedability formula yields ... 

Baobab seed kernels have an energy value of 1803 kJ/100 g (Arnold et al, 1985, cited in (11)). Arnold et al, cited in (11), provided data on chemical composition moisture 8.1%, protein 33.7%, fat 30.6%, carbohydrates 4.8%, fibre 16.9% and ash 5.9%. However, higher levels of carbohydrates have been recorded (Palmer and Pitman, 1972, cited in (11)). According to (55), the seed contains relatively high amounts of protein, crude fat, and crude fibre, and low levels of carbohydrates. The baobab seeds have been subjected to extensive research, a the proximate analysis of the seeds are provided (Table VI). 

Depending in part on the preparation method, humic substances may be subject to these problems. However, since oxygen is a major constituent of humic substances, it is important to know its true value. As discussed above, careful accounting of the moisture content of the sample is critical. One should also have information on the composition of the ash so that its effect on the oxygen analysis can be considered. If HF has been used to remove ash constituents, the sample should be analyzed for fluorine residues. 

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