Scratch analysis

An accurate determination of critical load Wcr is sometimes difficult. Several techniques, such as (1) microscopic observation (optical or SEM) during the test, (2) chemical analysis of the bottom of the scratch channel (with electron microprobes), and (3) acoustic emission, have been used to obtain the critical load. 

The framework, however, as introduced so far is of little help for our purpose since the shift from any subspace to its immediate in hierarchy would require to change entirely the set of basis functions. Although j x) are all created by the same function, they are different functions and, consequently, the approximation problem has to be solved from scratch with any change of subspace. The theory of wavelets and its relation to multiresolution analysis provides the ladder that allows the transition from one space to the other. 

Conformation analysis methods. In many cases in the process of building a 3D structure from scratch, decisions have to be made between multiple alternatives with similar energy. A typical example is an sp -sp torsion angle with similar energies for the alternatives of -i-60°, -60° and 180°. In many cases, rules are used to decide (e.g. stretch an open chain portion as much as possible to avoid clashes). Sometimes, the best result cannot be determined without a conformation analysis (e.g. complex ring systems with exocycHc substituents). Despite conformation analysis being a topic of its own covered in the next chapter, many automatic 3D structure generators have to fall back in certain situations to a limited conformation search in order so solve a specific problem and to come up with a reasonable solution. 

A variety of public and proprietary checklists are available that vary in comprehensiveness. There is no reason for an organization to start from scratch in developing a checklist. A human factors checklist and tables are included in Chapter 6. The Systematic Cause Analysis Technique (SCAT)< > is an example of a proprietary checklist. The accompanying CD-ROM also contains examples of checklists which can be modified for the readers use. 

Ten of 12 workers experienced acute irritant contact dermatitis of the hands after 2 days of direct contact. In the most severe case, a woman with no previous skin problems, who wore latex gloves intermittently, had painful swelling of the fingers of both hands with redness and vesicles on the palms. The affected skin later became thickened and showed a brownish discoloration. Another worker noticed small vesicles on the forehead, probably due to scratching with contaminated fingers. All cutaneous reactions cleared within 3 weeks of termination of exposure. Gas chromatograph analysis of the NMP used at the factory did not reveal any contaminating compounds. 

Diffuse reflectance is an excellent sampling tool for powdered or crystalline materials in the mid-IR and near-IR spectral ranges. Heated reaction chambers for diffuse reflectance allow the study of catalysis and oxidation reactions in situ, and can evaluate the effects of temperature and catalyst behavior. Scratching sample surfaces with abrasive paper and then measuring the spectra of the particles adhering to the paper allows for analysis of intractable solids. Perhaps one of the greatest additional benefits is that this system is amenable to automation. 

Evolvability and adaptability are usually crucial, but an additional dependability challenge. A particular problem is that, just as with ordinary systems, whatever analysis was undertaken in order to establish that an infrastructure is likely to be adequately dependable, may have to be redone virtually from scratch for a modified version of the infrastructure. (Ideally the amount of reworking of the dependability analysis would be commensurate with the extent of the change.)... 

For certain clearcoat systems a partial healing of scratches can be observed on the time scale. In literature this is known as the reflow effect [21], Thermal relaxation phenomena may be used for a physical explanation of this effect. In connection with scratch resistance the cross-linking density of clearcoats is also a decisive factor. Meanwhile, dynamic mechanical analysis (DMA) has been established as a method to determine cross-linking density [21-23],... 

---