Knots density

Definitions of the commonly measured tensile properties are as follows Unear density (tex) is the weight in grams of 1000 m of yam. Tenacity is the tensile stress at break and is expressed in force-per-unit linear density of unstrained specimen, N /tex. Knot tenacity is the tensile stress required to mpture a single strand of yam with an overhand knot tied in the segment of sample between the testing clamps. It is expressed as force-per-unit linear density and is an approximate measure of the britdeness of the yam. Toop tenacity is the tensile stress required to mpture yam when one strand of yam is looped through... 

Latex balloons are made of polymers. The latex near the knot and top of the balloon are not stretched as tightly as latex on the side. This can be seen by observing the transparency of the different parts of the balloon. The knot and top areas of the balloon have a greater polymer density. Therefore, the balloon in these areas has a greater ability to stretch and partially seal itself around the skewer. On the sides of the balloon, the tightly stretched latex cannot seal around the needle and the balloon pops. 

Fine-grained TNT of density 0.8, in a chge 4.9 mm diam, initiated with "Knotted Primacord had an initial vel of 1400 m/sec at a distance from initiator 53cm then, at... 

TNT , 50% fine 50% coarse (-6+8 mesh) of density 1.12 and chge diam 4.8 mm, initiated with "Knotted Primacord" had initial vel of 2070 at the distance from initiator of 5.0 cm, then at the distance of 7.4 cm the vel was 3190 and after this a stable regime was established with vel 5150m/sec. The three-regime transient phenomena are also illustrated by framing-camera results for cast TNT shown in Fig 3.13, p 55. Here... 

It can be seen in this expression how the knot spreads, its energy density going to zero. 

Figure 9.4 Schematic representation of the macromolecular architecture of a large gel-forming respiratory mucin. Two mucin subunits, each about 500 nm in length, are joined end to end via disulfide bonds (S-S) and consist of oligosaccharide-rich regions (represented by the thickened line) and folded domains stabilized by disulfide bonds (represented by the knots). An expanded portion of one of the oligosaccharide-rich regions (not drawn to scale) shows the variety and density of the attached O-linked glycans...

The beauty of a molecular knot is naturally related to its representation and to the shape of the molecule itself [18] and, in all walks of chemistry, there are more and less beautiful representations of knotted structures. Few people envisage these beautiful molecules as the clouds of electron density and atomic nuclei that they are, but with computer-aided design it is likely that these attractive molecules will find renewed interest from those eager to attempt totally synthetic challenges in synthesis through template methods. One has simply to behold the remarkable and... 

Therefore, the time-dependent density F j (t) of initial knots in the blend is proportional to the relaxation function of each species involved in the knot, that is to say ... 

From that relation, it can be shown that the density of (i, j) knots is equal to the geometric average of the density of knots between similar chains ... 

A hierarchical succession of steps marks out the wood quality chain, beginning with the intrinsic characteristics and features of the wood cell (Table 5.1). The spatial arrangement hints at the relationships between characteristics, properties and product specifications, but they are less obvious than is usually acknowledged. For furniture one would expect adequate density (revealed in properties such as stiffness, strength and hardness), straight grain, absence of reaction wood and tight knots... 

As one might anticipate, the two key characteristics influencing the strength of clearwood are density and MFA. However, a further effect is that of branches/knots on the local strength in their immediate vicinity. Discussion on the role of knots is deferred to Chapter 10. 

The attraetion of machine grading lies in the fact that individual pieces are tested so that the defleetion in bending (the usual method for alloeating a pieee to a grade) reflects both the natural defects (knots etc) and the intrinsie features (density, MFA etc.) of that piece. 

Another method of sorting maehine-graded timber is to use density to estimate knot size and frequency. X-ray sources in eonjunetion with a series of deteetors gather density profiles in the timber, which are sensitive to knots. This information is then used to assign the graded pieee to a not to exeeed grade eategory. 

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