Pitch definition

A plasticizer is a substance the addition of which to another material makes that material softer and more flexible. This broad definition encompasses the use of water to plasticize clay for the production of pottery, and oils to plasticize pitch for caulking boats. A more precise definition of plasticizers is that they are materials which, when added to a polymer, cause an increase in the flexibiUty and workabiUty, brought about by a decrease in the glass-transition temperature, T, of the polymer. The most widely plasticized polymer is poly(vinyl chloride) (PVC) due to its excellent plasticizer compatibility characteristics, and the development of plasticizers closely follows the development of this commodity polymer. However, plasticizers have also been used and remain in use with other polymer types. 

With regard to coal-derived tar and pitch, the following definitions are appropriate to distinguish them from ostensibly similar materials from other sources and from cmde oil in particular. 

Two other terms need definition transverse pitch a and longitudinal pitch b. For a drawing of these dimensions see the source article. For our purposes appropriate lengths are shown in Table 3. 

Figure 4.9. Flame speed-distance relationship of methane-air fiames in adoubie piate geometry (2.5 X 2.5 m) as found by Moen et al. (1980b). Tube spirals (diameter H = 4 cm) were introduced between the plates (plate separation D). The pitch P (see Figure 4.8 for definition) was held constant. P = 3.8 cm. (a) H/D = 0.34 (b) HID = 0.25 (c) H/D = 0.13.

Twenty years ago, Walter Riidorff wrote a review for this series entitled "Graphite Intercalation Compounds Oil). It was one of four definitive articles to come out in 1959 and 1960 (HI, Cl, Ul), a period of intense activity in graphite research. We have now again reached the "fever pitch, with not only the appearance of several new articles El, H2, Wl) but also the convening of the first international conference dedicated exclusively to graphite compounds (H3). In the following, we shall concentrate on work performed between 1974 and the present. 

What we argue (of course it is tme) is that the Laplace-domain function Y(s) must contain the same information as y(t). Likewise, the function G(s) contains the same dynamic information as the original differential equation. We will see that the function G(s) can be "clean" looking if the differential equation has zero initial conditions. That is one of the reasons why we always pitch a control problem in terms of deviation variables.1 We can now introduce the definition. 

A quantitative study of the cholesteric induction and of the chiral transfer from dopant to phase requires the definition of the helical twisting power 3. This quantity expresses the ability of a chiral dopant to twist a nematic phase and can be numerically expressed in Eq. (2) where p is the cholesteric pitch, c the dopant molar fraction, and r its enantiomeric excess its sign is taken to be positive or negative for right-handed (P), or left-handed (M) cholesterics, respectively. This relation holds for molar fractions <0.01-0.05 ... 

FIGURE 5.11 Supramolecular, helical architecture and definition of pitch length p of chiral nematic liquid crystals. 

The fuel oils coming out of olefin plants are also characterized by an abundance of polynuclear aromatic molecules, (Same definition as for Figure 2—1). They are sometimes inaccurately referred to as having a high aromatics content. Nomenclature aside, because of this, the burning characteristics of pyrolysis gas oil and pyrolysis pitch are poor. They are smoky, sooty, and gum formers they rend to be more viscous, and because of their polynuclear aromatic concent, they are suspected carcinogens. They are basically a witchs brew of unsavory hydrocarbons.. ... 

These rather crude relations could easily be improved but they go as far as the flat crests warrant and they seem definitely to exclude any other pitch. Thus occurs 6 times, 4 times and d not at all, even when this is the telephone pitch. Finally the double crests in figures 9 and 10 are the octaves 6, stimulated by the d (c.f. survey of pipe crests,... 

The arming vane may drive a gear train which, after a definite interval, removes safety blocks or aligns the detonator with the next element in the explosive train. Standard arming vanes have blade pitches of 30°, 60°or 90°, but there are also "special" vane assemblies with different blade pitches (Ref 51a, p 5-38)... 

Fig. 12. Definition of solid state structural parameters for tris chelate complexes with D3 symmetry 0 is the twist angle and is the projection of the bite angle a onto the plane which is perpendicular to the C3 symmetry axis, 0 is the pitch angle and is the angle subtended by the plane of the chelate ring and the C3 symmetry axis r, d, s and h are the metal ligand distance, bite distance, triangle edge, and the distance between the triangles, respectively. From Ref.82 ...

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