Shrink mark

However, when the temperature increases further, the PNIPA network shrinks markedly, followed by a concomitant slowing down of the diffusion of reactants within the network. This in turn will lower the rate of reaction catalyzed by the metal nanoparticles. It is obvious that the increase of kapp by the raise of temperature is overcompensated by the diffusional barrier. Hence, the reaction rate must reach its minimum at the transition temperature. If the increase of temperature continues, the PNIPA network will not shrink any more and the density within the network stays constant. Now, the strong increase of kaW with T will be predominant and the... 

Finishing Wool Fabrics. The fundamental chemical structure of the wool fiber, together with its fiber morphology, impose an entirely different procedure in finishing wool fabrics than that outlined for the cellulosic fiber fabrics. Wool is sensitive to strong alkali, the fiber shrinks markedly with wetting, and the fiber felts under a suitable combination of mechanical work, chemical action, moisture, and heat. 

Forging produces parts with no flash or trim, sprue marks, weld lines, or shrink marks. This reduces scrap and permits good surface finish. 

Bosses are used to reinforce holes in the part and to provide mounting locations. Solid bosses are called studs. Bosses must be molded with rounded corners and adequate fillet radii. They usually are located in a corner or juncture of two or more surfaces to minimize the effects of sinking. The problem of shrink marks is lessened with GRTP because of their reduced shrinkage. It is generally recommended that the height of the boss be limited to twice its diameter. Vertical surfaces should have at least a 1 deg draft per side. Recommended designs are shown in Fig. 6-5. 

Some types of soils, particularly so-called expansive clays, expand and shrink markedly as they become saturated with water and dry out. Although essentially never life-threatening, Ihe movement of structures and the damage caused to them by expansive clays can be very high. Aside from years when catastrophic floods and earthquakes occur, the monetary damage done by the action of expansive soil exceeds that of earthquakes, landslides, floods, and coastal erosion combined. 

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