Network Terms Links

Walmart now tops the Fortune 500 list. For the last 25 years, the company has outperformed competitors. One of the reasons is Walmart s investment in supply chain management. A competitive advantage is Walmart s building and usage of a supplier network termed Retail Link. Today, you would not think of being a supplier to Walmart without the use of the Walmart Retail Link. 

From the supply chain network perspective, it is expected that the influence of lean supply chains focuses on establishing long-term links among the supply chain units and minimization of number of units and links. The lean supply chains aim towards simplifying and streamlining the supply chain network, while providing a high level of standardization and specialization. 

The central term (polymer) is marked yellow and the network of links becomes more and more complex with increasing distance ffom the term. In the above example, there is a distant link from polymer to the metric term dose, a physicochemical process like gelation and s)meresis, and a mathematical/ theoretical term like geometrical equivalence (in polymers). ... 

The ordinate values, A n and Aj, denote the square root of the components of the molecular deformation tensor parallel and perpendicular to the direction of stretch, respectively. Results are presented in terms of o( for networks cross-linked and stretched in the dry state, i.e., v v = 1. 

The lines between the nodes of the dyad as shown in Figure 3.7, Social Network Terms , have arrowheads that represent the direction of the flow of information between three nodes. In this example, we show two-way communication between the three nodes. In addition, the link can be used to specify other characteristics of the link between the nodes. For example, you can show if the communication is daily or weekly, if it is a positive or negative relationship, or other characteristics that you may want to evaluate. 

Kinship as a network that links people over time and space is difficult to detect at Ebla because such connections between people are so basic, so foundational, that they require no explication. But they may be glimpsed in operation from time to time, as has been seen already with ancestors in this chapter. They are also evident in the use of kinship terms, especially in Eblaite onomastics (Bonechi 1997 Fronzaroli 1998). Thus far this evidence attests primarily... 

We noted above that the presence of monomer with a functionality greater than 2 results in branched polymer chains. This in turn produces a three-dimensional network of polymer under certain circumstances. The solubility and mechanical behavior of such materials depend critically on whether the extent of polymerization is above or below the threshold for the formation of this network. The threshold is described as the gel point, since the reaction mixture sets up or gels at this point. We have previously introduced the term thermosetting to describe these cross-linked polymeric materials. Because their mechanical properties are largely unaffected by temperature variations-in contrast to thermoplastic materials which become more fluid on heating-step-growth polymers that exceed the gel point are widely used as engineering materials. 

Fibers. The principal type of phenoHc fiber is the novoloid fiber (98). The term novoloid designates a content of at least 85 wt % of a cross-linked novolak. Novoloid fibers are sold under the trademark Kynol, and Nippon Kynol and American Kynol are exclusive Hcensees. Novoloid fibers are made by acid-cataly2ed cross-linking of melt-spun novolak resin to form a fuUy cross-linked amorphous network. The fibers are infusible and insoluble, and possess physical and chemical properties that distinguish them from other fibers. AppHcations include a variety of flame- and chemical-resistant textiles and papers as weU as composites, gaskets, and friction materials. In addition, they are precursors for carbon fibers. 

It is somewhat difficult conceptually to explain the recoverable high elasticity of these materials in terms of flexible polymer chains cross-linked into an open network structure as commonly envisaged for conventionally vulcanised rubbers. It is probably better to consider the deformation behaviour on a macro, rather than molecular, scale. One such model would envisage a three-dimensional mesh of polypropylene with elastomeric domains embedded within. On application of a stress both the open network of the hard phase and the elastomeric domains will be capable of deformation. On release of the stress, the cross-linked rubbery domains will try to recover their original shape and hence result in recovery from deformation of the blended object. 

In terms of tonnage the bulk of plastics produced are thermoplastics, a group which includes polyethylene, polyvinyl chloride (p.v.c.), the nylons, polycarbonates and cellulose acetate. There is however a second class of materials, the thermosetting plastics. They are supplied by the manufacturer either as long-chain molecules, similar to a typical thermoplastic molecule or as rather small branched molecules. They are shaped and then subjected to either heat or chemical reaction, or both, in such a way that the molecules link one with another to form a cross-linked network (Fig. 18.6). As the molecules are now interconnected they can no longer slide extensively one past the other and the material has set, cured or cross linked. Plastics materials behaving in this way are spoken of as thermosetting plastics, a term which is now used to include those materials which can in fact cross link with suitable catalysts at room temperature. 

Many properties of silicates can be understood in terms of the type of network lattice formed. In the one-dimensional networks, shown in Figure 17-8, the atoms within a given chain are strongly linked by covalent bonds but the chains interact with each other through much weaker forces. This is consistent with the thread-like properties of many of these silicates. The asbestos minerals are of this type. 

Here, b denotes the Kuhn s statistical segment length. The network is represented by a huge chain internally cross-linked at cross-linking points where it touches and at the surfaces of Mf filler particles. The point-like local cross-hnk constraints are easy to handle and can be represented by the term... 

Elasticity measurements can serve as a measure of the degree of interconnection in gels. Covalently cross-linked networks can be distinguished from physically cross-linked networks by the use of a technique termed mechanical spectroscopy [333]. Compression of gels has also been used to assess the physical structure [28,168,303]. 

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