Appearance of the samples

Three different types of feature have been observed on the coupons surfaces — uneven oxidation, even oxidation and pitting — as is shown in 

Evolution of chemical variables in the RA3 DP. TSS total soluble solids. 

The first type of feature, uneven oxidation, relates to the internal sides of sandwiches (either crevices or galvanic couples). The inhomogeneous coloration indicates uneven matching of the two surfaces, which leaves zones with more or less access of water in these surfaces only small pits have been found. 

The results indicate a much better water quality in both the RA6 RP and the RA6 DP than in the CSF lines. 

Corrosion effects have been encountered. They are mainly related to the water quality of the sites studied. The three main consequences are oxidation, crevice attack, and galvanic corrosion and pitting. 

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Decolorisation by Animal Charcoal. It sometimes hap pens (particularly with aromatic and heterocyclic compounds) that a crude product may contain a coloured impurity, which on recrystallisation dissolves in the boiling solvent, but is then partly occluded by crystals as they form and grow in the cooling solution. Sometimes a very tenacious occlusion may thus occur, and repeated and very wasteful recrystallisation may be necessary to eliminate the impurity. Moreover, the amount of the impurity present may be so small that the melting-point and analytical values of the compound are not sensibly affected, yet the appearance of the sample is ruined. Such impurities can usually be readily removed by boiling the substance in solution with a small quantity of finely powdered animal charcoal for a short time, and then filtering the solution while hot. The animal charcoal adsorbs the coloured impurity, and the filtrate is usually almost free from extraneous colour and deposits therefore pure crystals. This decolorisation by animal charcoal occurs most readily in aqueous solution, but can be performed in almost any organic solvent. Care should be taken not to use an excessive quantity... 

Concentration of TEOS in all these cases has been restricted up to 50 wt% with respect to the mbber. Beyond 50 wt%, all the hybrids show phase separation which may be due to higher amount of water condensate that is continuously generated and acts as nonsolvent for the mbbers. This is easily understood from the visual appearance of the samples phase-separated composites slowly turn opaque in the course of gelation. 

Samples are generally prepared and analyzed in sets of 30 that include at least one control and one fortified control water sample. Optima-grade bottled water may be used as the matrix for the controls and the laboratory-fortified samples for all water types. Depending on the appearance of the samples, filtration may be required. 

At pH 3, ketoprofen is mostly in an uncharged state in solution. The dashed curve in Fig. 7.16 corresponding to pH 3 shows a rapid decline of the sample in the donor well in the first half-hour this corresponds to the membrane loading up with the drug, to the extent of 56%. The corresponding appearance of the sample in the acceptor well is shown by the solid line at pH 3. The solid curve remains at zero for t < xLAG. After the lag period, the acceptor curve starts to rise slowly, mirroring in shape the donor curve, which decreases slowly with time. The two curves nearly meet at 16 h, at a concentration ratio near 0.22, far below the value of 0.5, the expected value had the membrane retention not taken a portion of the material out of the aqueous solutions. 

When a sample is received it should have a unique identification, i.e. a number or code. All details about the sample should be recorded. This will include storage conditions and, if it is necessary to transfer the sample from person to person, this should be fully documented. Details of the container and closures should also be recorded. These may have been inappropriate and influence the analytical result. The appearance of the sample on receipt should also be documented. 

Initially the q phase was assigned as the nonmolecular form of nitrogen, assuming the cubic gauche structure suggested by Mailhiot as the most likely [324]. However, the value of the band gap and the opaque appearance of the sample are not suited for an extended array of N-N single bonds. As a matter of... 

Thermal/humidity stress testing involves exposing samples to various conditions of temperature and humidity. Once the conditions are chosen, the samples are placed in either ovens which control the conditions or saturated solutions of salts in desiccators. The physical appearance of the sample is important and should be monitored throughout the study. In addition, any loss or gain of water should be noted as well. 

Place (he bottle with contents in a chamber maintained at 65.5°il°C (See Fig oa p 28 of Ref 12 and on p 49 of Ref 13), the air in which is preferably maintained in constant circulation After (he bottle with contents has been heated for 24 hrs, reseat (he stopper. Make daily observation of the appearance of the sample and note the number of days required to cause (he liberation of visible reddish or brownish fumes of oxides of nitrogen Note It has been customary to consider any proplnt having a test value of 90 days or less to be of definitely impaired stability and any proplnt having a test value of 20 days or less to be sufficiently unstable as to require destruction or salvage... 

The experiments were conducted as follows the sample was loaded into the sample loop of the injection valve and a valve at the cell outlet was opened to allow fluid from the pump to flow through the cell. The sample loop was then switched in line and the absorbance monitored to detect the appearance of the sample in the cell. The solute (probe) concentration was diluted by introduction of additional solvent to obtain the desired concentration (and... 

To address a concern that there might be substantial quantities of unobserved elements, the total accountable mass of each sample was computed. Only one sample (804) had an accountable mass close to 100%. This mass was calculated without corrections for the possible corrosion of copper and iron that contributes oxygen. The corroded appearance of the sample would... 

Last, but not least, all phases and details of sampling and sample treatment in the field must be faithfully and exhaustively recorded along with details of storage and transport to the laboratory. Description of the appearance of the samples, weather conditions, temperature, devices and materials used and unexpected... 

The appearance of the sample was quite different from that in Procedure 7. After only one exposure, the sample was dark in color, indicating a more uniform deposition of polyacetylene throughout. Multiple exposures gave an even darker membrane. 

K. Phase IV, on the other hand, is obtained by heating either phase III below 23 GPa, or phase II at higher pressures. These transformations can be readily observed by abrupt changes in the visual appearance of the sample and in the Raman spectrum, similarly to the case of CO2 phases. 

As in the case of the Sieverts technique, the appearance of the sample density on the bottom line in Eq. (7.13) implies a sensitivity of the result to sample density and increased buoyancy forces with samples of low density. Equation (7.14) shows that the best outcome is with matched sample and tare-weight densities as well as matched masses, thus cancelling the buoyancy force on the sample. At the opposite extreme, the single-sided balance (or a double-sided balance with grossly mismatched sample and tare-weight densities) requires careful calibration with an inert gas as discussed in Section... 

Tomy et al. (1997) introduced the numerical correction factor, average molar mass (AMM), to correct for differences in the appearance of the sample and standard [11]. Using the AMM, the authors demonstrated that the error in quantifying one technical mixture using another as an external standard was less than 40% [62],... 

The true colors of some minerals can only be seen when the sample is finely powdered. Rather than grinding up a specimen, a small area is rubbed against a hard porcelain surface until a streak of the mineral is obtained. The color obtained in this streak test can be quite different from the appearance of the sample itself. For example, samples of specular hematite (the word specular refers to the mirror-like surface) have a very shiny black appearance due to the reflective nature of the naturally polished surface. The streak test reveals the true color of hematite—a red-brown. 

The first step in the identification of polymers is a critical visual examination. While the appearance of the sample may indicate whether it is essentially a raw polymer or a compounded and processed item, learning about its form, feel, odor, color, transparency or opacity, softness, stiffiiess, brittleness, bounce, and surface texture may be important in the process of the identification of the polymer. For example, polystyrene, the general purpose polymer, is transparent and brittle, and produces a characteristic metallic tinkle when objects molded from it are dropped or struck. 

In order to quantitatively evaluate the smoothness of a surfaee, which has considerable influence on the total gloss appearance of the sample, it is necessary to objectively measure this phenomena. The measurement of specular gloss and reflection haze does not take into account the visual impression of orange peel. Also the measurement of image clarity correlates poorly with the visual ranking of orange peel. 

The experiments in POW resemble the conditions of the NMR experiments. Based on the appearance of the samples at the end of the experiments (disintegrated in the case of PVA and rodlike brittle in the case of PVAc) it was postulated that PVA dissolves faster, while PVAc dissolves slower than the cementitious matrix establishes. This is exactly backed up by the XRD measurements in the case of PVA, less than 10% of the clinker phases had hydrolysed at the time the sample disintegrated (8h), while after 48h, the time of full sample saturation, more than 40% of the clinker had reacted in the c/PVAc sample. 

We note here also that, unlike collective diffusion coefficients, molecular self-diffusion coefficients are unaffected by critical effects, which is a significant advantage for systems with critical points, a typical situation in this context. We also note that self-diffusion studies are very general and that the NMR approach places little demand on the appearance of the sample (turbidity, color, rheology, etc.)... 

To eonelude this seetion we summarize the main advantages of the NMR diffusion method as applied to emulsion droplet sizing. It is nonperturbing, requiring no sample manipulation (such as dilution with the continuous phase) and, as noted above, it is nondestructive. It is insensitive to the physical appearance of the sample, and can be applied to nontransparent samples. It requires small amounts of sample (typically of the order of a few hundred milligrams) and is normally quite rapid (of the order of 10 min per sample). 

Figure 1 provides several examples of the changes in appearance of the sample-surfactant-solvent mixtures which occured as water content increased. 

Precursor Precursor concentration in the feed (wt%) Solvent Temperature of the gelation process (°C) Appearance of the samples after the gel formation process References... 

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