Loop strength

The loop strength ratio on the other hand is defined as the ratio of the loop breaking strength as measured in accordance with BS 1932. Part 2 to twwe the yarn breaking strength measured in accordance with ISO 2062,... 

The knot configuration in BS 1932, Part 2, as shown in Fig. 29, is for a Z twist yarn, and a different configuration is shown for an S twist yarn, but no configuration is show n for the loop strength test. 

Loop strength tenacity The tenacity or loop strength value obtained by pulling two loops against each other that can cause the fibrous (particularly glass) material to be cut and/ or crushed. 

Thus the hysteresis loop should close at a relative pressure determined by the tensile strength of the liquid adsorptive, no matter whether the pore system extends to finer pores than those characterized by or not. 

Fig. 3.24 Test of the tensile strength hysteresis of hysteresis (Everett and Burgess ). TjT, is plotted against — Tq/Po where is the critical temperature and p.. the critical pressure, of the bulk adsorptive Tq is the tensile strength calculated from the lower closure point of the hysteresis loop. C), benzene O. xenon , 2-2 dimethyl benzene . nitrogen , 2,2,4-trimethylpentane , carbon dioxide 4 n-hexane. The lowest line was calculated from the van der Waals equation, the middle line from the van der Waals equation as modified by Guggenheim, and the upper line from the Berthelot equation. (Courtesy Everett.)...

For the measurement of magnetisation in hysteresis-loop measurements, a search coil consisting of several-turn windings around a specimen is coimected to a fluxmeter whose output can be recoded on thejy-axis of an x,y plotter. The x-axis records the field strength of the primary coil around the specimen. The whole procedure can be done conveniendy in a hysteresigraph, whereby the induction is recorded automatically as the field is varied continuously. 

Because of its high strength and toughness, spun nylon yams tend to form unsightiy pihs, ie, balls of fiber on the fabric surface containing some short lengths of fiber, in flat woven and apparel fabrics. This is also why bulked continuous-filament yam (BCE) is preferred over spun yams for loop pile carpets. 

There is also evidence for stable 3,4-adducts from the X-ray analysis of 2-amino-4-ethoxy-3,4-dihydropteridinium bromide, the nucleophilic addition product of 2-aminopteridine hydrobromide and ethanol (69JCS(B)489). The pH values obtained by potentiometric titration of (16) with acid and back-titration with alkali produces a hysteresis loop, indicating an equilibrium between various molecular species such as the anhydrous neutral form and the predominantly hydrated cation. Table 1 illustrates more aspects of this anomaly. 2-Aminop-teridine, paradoxically, is a stronger base than any of its methyl derivatives each dimethyl derivative is a weaker base than either of its parent monomethyl derivatives. Thus the base strengths decrease in the order in which they are expected to increase, with only the 2-amino-4,6,7-trimethylpteridine out of order, being more basic than the 4,7-dimethyl derivative. 

With years of research and development in the field of static drives, it is now possible to identify and separate the.se two parameters (f, and /, ) and vary them individually, as in a d.c. machine, to achieve extremely accurate speed control, even slightly better than in d.c. machines. In d.c. machines the armature current and the field strength arc also varied independently. A.C. machines can now be used to provide very precise speed control, as accurate as 0.001% of the set speed, with closed-loop feedback controls. This technique of speed control is termed I ield-oriented control (FOC) and is discussed below. 

The functional reaction center contains two quinone molecules. One of these, Qb (Figure 12.15), is loosely bound and can be lost during purification. The reason for the difference in the strength of binding between Qa and Qb is unknown, but as we will see later, it probably reflects a functional asymmetry in the molecule as a whole. Qa is positioned between the Fe atom and one of the pheophytin molecules (Figure 12.15). The polar-head group is outside the membrane, bound to a loop region, whereas the hydrophobic tail is... 

Typically, the level of glycol required in a HW heating system is only 15 to 25% v/v or so (less than the 35 15% usually employed in cold and chilled-water closed-loop systems). Where glycols are added, the system must be cleaned and flushed first. The system can be partly drained to accommodate the volume of 100% glycol required or alternatively filled with a prediluted mix. If a 20% v/v strength is required, 25% v/v should be specified to allow for inaccuracies in mixing. 

---