Fiber stress, mass

Fiber stress, mass Force per unit mass per unit length in grams per linear denier. Used the same way as force per unit area. 

The instrumental aspects and applications of stress mass spectrometry (stress MS) to polymeric materials is reviewed critically from the inception of the technique to the present. Stress MS experiments are performed by mechanically deforming polymeric materials directly in the ion source housing of a time-of-flight mass spectrometer and mass analyzing the evolved volatile compounds. This technique has been applied to the study of stress-induced chemical reactions in polymeric materials, i.e., mechanochemistry, and to the characterization of residual volatile compounds in intractable polymer and composite matrices. Several polymeric systems ranging from polystyrene to fiber-epoxy composites have been studied by this technique. The significance of results achieved to date is assessed, and a systematic framework for further studies is developed. 

The elasticity of a fiber describes its abiUty to return to original dimensions upon release of a deforming stress, and is quantitatively described by the stress or tenacity at the yield point. The final fiber quaUty factor is its toughness, which describes its abiUty to absorb work. Toughness may be quantitatively designated by the work required to mpture the fiber, which may be evaluated from the area under the total stress-strain curve. The usual textile unit for this property is mass pet unit linear density. The toughness index, defined as one-half the product of the stress and strain at break also in units of mass pet unit linear density, is frequentiy used as an approximation of the work required to mpture a fiber. The stress-strain curves of some typical textile fibers ate shown in Figure 5. 

Given the availability of hollow fiber membranes adequately permeable to substrates and products, and the control of fluid flow all around the fibers in the bundle in order to assure uniform flow distribution and to avoid stagnation (in order to reduce mass transfer diffusional resistances), the technique offers several advantages. Enzyme proteins can be easily retained within the core of the fibers with no deactivation due to coupling agents or to shear stresses, and the enzyme solution can be easily recovered and/or recycled. 

B). The dimeric a-actinin, a member of the spectrin family, has a subimit mass of 97 kDa. Found primarily in the Z-discs, it is also present in nonmuscle cells in stress fibers and at other locations in the cyto-skeleton (Chapter 7). It may anchor actin filaments to various structures outside of the sarcomere. In the dense Z-disc of insect flight muscle a regular hexagonal lattice of a-actinin and a large (500-700 kDa) modular profein called bind the thin... 

A final operation is needed to obtain the target product by determining its formulation, so that its properties correspond to its intended uses. These products include plastics, synthetic fibers, fertilizers, solvents, elastomers, insecticides, detergents etc. Figure 1 illustrates the links existing between petroleum raw materials and mass-consumption finished products, and stresses the main processes employed. 

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