Teeth, contact angle

In this report, these concepts are applied to real proteins to collagen, an important structural material in tendons, bones, teeth, and skin, and to gelatin, the denatured product of collagen that is so important industrially. These materials are complex because of their 18 different, component amino acid side chains in addition, they present experimental difficulties because of their water solubility— they cannot be washed (e.g., with an aqueous detergent) to assure surface cleanliness. Furthermore, they are often of unknown purity. They do have the common polyamide backbone, and it is possible to transform the molecular configuration. The data are indicative of the potential utility of contact angle measurements of important, natural materials. No claim is made for adequate attention to the complex biochemistry of these materials. 

Baier also conducted preliminary contact-angle studies on human teeth in situ (14). He determined values of critical surface tension to be approximately 32 dynes/cm for teeth which had been recently cleaned with toothpaste. A similar value was obtained for teeth not as recently cleaned. Taking other factors into consideration, a surface energy of 30 to 40 ergs/cm represents the natural situation. The exact values are contingent upon individual eating and oral hygiene practices. 

Water Absorption and Contact Angle of Water Droplets and Glucose Absorption to PC Teeth Irradiated up to 7.0 kGy at 150°C in Nj Atmosphere... 

With large ratios, the angle of contact becomes smaller and the number of teeth engaged with the chain decreases. For angles less than 120°, 0 increasingly becomes a critical factor in the design of chain drives. 

Two important characteristics of gear teeth are the profile and the pressure angle. In particular, special tooth profiles must be used for higher gear speeds. As speeds increase, friction increases the heat released because of sliding contact between the teeth. 

Generally each tooth in contact on a sprocket should share the load. Therefore, sprockets with few teeth should have small pressure angles, and sproekets with many teeth should have much... 

Figure 3 shows the results of the rigid body analysis. The slip path ABCD is elliptical and has maximum interference at point A. There is no contact possible along the path BCD because the surfaces are separated. It is noted that the displacements depend only on the orientation of the tooth with respect to its local pressure angle and of the instantaneous misalignment vector. Therefore, all teeth in the coupling experience the same displacement history as the shaft rotates under a constant misalignment. 

Worm-gear reducers are very compact, requiring less space than belts, chains, or trains of open gearing. The right-angle drive often permits compact placement of the driving and driven machines. Since three or more teeth are always in contact. 

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