Inherent defects

With few exceptions, stains used in wood finishing are formulated to improve the appearance of the substrate. Unlike paints, sealers, and topcoats, stains are utilized either to accentuate the natural beauty of the wood or to hide inherent defects found in most species of wood. 

M. Birch, R. G. Brown and J. E. Brocklehurst, Dcfinning the Effective Inherent Defect Si/c of Graphite for Fracture Mechanics Applications, Extended Abstracts and Program-16 Biennial Conference on Carbon, Pub. American Carbon Society, 1983, pp 404405. 

One important feature in some of the new examination regulations is the recognition of the candidate s signed record of laboratory work. We are, in fact, beginning to discover an inherent. defect in practical chemistry as an examination subject, namely, its resistance to compression into a compact and convenient examination form. 

Inherent defects in either the system or the equipment, or infant mortality (see below) cause a low MTTF. Inherent defects will result in units failing more frequently than is desirable. These defects can be corrected by locating and correcting them or by taking action to reduce their effects, thus improving machine life. 

Infant mortality results in repaired units failing shortly after their return to service. It can be corrected by simplifying repair techniques, quality control of repairs and repair parts, improved starting techniques, etc. Units which have persistent abnormally short lives may have an inherent defect which cannot be corrected by the previous methods. However, the usual characteristic of infant mortality is its variability. Very good pumps of last year become the very bad ones this year and vice versa. Any pump is a potential bad actor. 

Fracture Mechanics Tests One problem of both sustained load and slow strain-rate tests is that they do not provide a means of predicting the behaviour of components containing defects (other than the inherent defect associated with the notch in a sustained load test). Fracture mechanics provides a basis for such tests (Section 8.9), and measurements of crack velocity as a function of stress intensity factor, K, are widely used. A typical graph of crack velocity as a function of K is shown in Fig. 8.48. Several regions may be seen on this curve. At low stress intensity factors no crack growth is... 

The resonance-mediated coupling mechanisms described above involve subtle quantal intramolecular/intermolecular donor-acceptor effects that tend to be inadequately described by current-generation empirical potentials. Simulations based on these potentials are therefore likely to be inherently defective for describing realistic folding processes in proteins. However, approximations such as those illustrated in Example 5.8 may ultimately make it feasible to incorporate additional resonance-mediated effects into empirical force fields of tractable form. 

Collectively, the inherent defects outlined above allow mechanisms by which electrons, heat and other substances can penetrate and move through a lattice, thereby enhancing the reactivity of pyrotechnic compositions. 

Trivial examples of metastability are solid solutions. Because these are inherently defect systems, they cannot be thermodynamically stable at low temperatures. Most of our high Tc superconductors need to be regarded as solid solutions which are then necessarily metastable phases. We could dismiss this as an irrelevant observation on the basis that solid solutions are merely required in order to adjust the carrier concentration to appropriate levels. However, we seem unable to generally make stable high Tc superconductors. One could even suggest that there is a correlation between Tc and metastability the higher the Tc, the more unstable. 

Aside from these inherent defects the fermentation method of resolution in particular is experimentally difficult since it requires large volumes of dilute solutions (1 to 5%) and periods of time ranging from 2 to 60 days. The facilities and technique for isolating pure cultures of micro-... 

The inherent defects of VB theory in its classical semi-empirical form are closely related to the premises listed above. They are ... 

We shall start with the basic concept that in the oxides formed on metals, (the same also applies to sulfides and halides) transport of material particles occurs only by the motion of inherent defects (Eigen-Storstellen) present in the lattice these defects are assumed to consist essentially of simple particles in interstitial lattice sites or vacancies of the particles constituting the crystal. The free electrons or holes which are present for reasons of electrical neutrality are coupled to the migrating defects and move considerably more rapidly. 

In this book, we try to present the basic concepts in order to understand the mechanical and electrical failures of solid materials containing inherent defects or disorders. Our emphasis has been on the question why , rather than on the question when , and we concentrate mainly on the statistical aspects of their failure strength distribution. 

CNDO/2 presents no comparable inherent defect. The main conclusions referring to the electronic displacements upon hydrogen bond formation emerged immediately in a very clearcut fashion and have not been changed by more recent calculations ). They are as follows 9 > ... 

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