type, the growing use of the flexible plastics in the rubber factory, shortages of rubber, and military demands for low temperature Briefly, the collective compounder is largely responsible for the cost and quality of all rubber products, he controls the sale of raw materials to the rubber manufacturer, and he coordinates the technical progress of the industry. He has available a host of materials, a number of rather well-developed theories, and the support Of people in It is UP to the individual compounder to use these resources with skill, judgment, and tact in order to get the best results on his service. In addition to the classes of materials in general use, there are a number of materials, such as antiseptics, blowing agents for sponge rubber, odorants, peptizing agents, and retarders, which are used in special cases.In latex compounding all materials must be used as solutions or dispersions in water. This requires not only knowledge of colloidal Dhenomena but also a number of special types of materials. Some Miscellaneous Materials.phases Of the bf the more important types are antifoam agents, coagulants, dis-own particular problems. persing and wetting agents, gelling agents, and preservatives.

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The results of this investigation strongly support previous conclusions by the authors that the softening of reinforced rubber when it is stressed to moderate extensions owes little to breakdown of filler chain structure and is due primarily to rupture of attachments between the filler and the rubber molecules. This means that the stiffness of reinforced rubber is influenced greatly by the mode of attachment of filler to rubber, and the conclusion reached is that such stiffening by finely divided fillers is largely a consequence of linkages between rubber molecules formed through the filler particles by rubber-filler bonds and assisted by the presence of coherent chain structure of the filler particles themselves. The work further suggests that the linkages formed through carbon particles are of two kinds : one a relatively weak type linkage due to physical (van der Waals) attachments, the other a strong type linkage due to chemisorptive attachments which remain unbroken by stressing. The strong linkages are relatively few and have not been found with fillers other than carbon black, but the strength distribution of the weaker type does not depend on the chemical nature or type of filler, although differences are found in the total number of such relatively weak attachments. The weak linkages are substantially all broken in the course of stressing to high elongations and the stiffening at the highest elongations is a consequence of the relatively small number of strong linkages. It is to be expected that among the fully reinforcing carbon blacks, where the particle sizes of the different types are roughly equivalent, those providing the greatest number of strong linkages will have the greatest reinforcing ability, and it may be significant in this connection that HAF black vulcanizates are recognized to have better abrasion resistance than MPC vulcanizates, in keeping with a larger number of strong linkages.

Malignant transformation of wounds is a rare complication that if missed can lead to loss of life or limb. This case report presents a rare invasive variant of squamous cell carcinoma presenting in the setting of a chronic wound complicated by osteomyelitis. This aggressive form of squamous cell carcinoma has a high growth rate and a high propensity for metastasis and recurrence. Early intervention greatly decreases the risk of metastasis and recurrence. We present the systematic evaluation and surgical management of an aggressive primary tumor occurring in the forefoot.