Measurements on the Thermal Expansion of Fused Silica (Classic Reprint) PDF Download

Author: Wilmer Souder
Publisher: Forgotten Books
ISBN: 9780428928629
Category : Technology & Engineering
Languages : en
Pages : 34

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Book Description
Excerpt from Measurements on the Thermal Expansion of Fused Silica The vertical position wires are illuminated by 10-watt mazda frosted spherical lamp bul'os. Resistances in the lamp circuit are used to reduce the illumination to a satisfactory intensity. By placing parallel spider lines in the reticle of the microscope to caliper the position wires. An excellent arrangement for high-precision measurements is secured. The air furnace in Figure 2 has external control rheostats for each side and end of the heating chamber. The external heat loss from these rheostats is reduced by using a transformer for the lower temperature tests. With all furnaces it is essential that the horizontal condition of the specimen shall not change during the test. A further precaution. For the bath furnace requires that the readings be made at a known distance above the end of the specimen and that the exact ratio of distances - level of observation to upper support of wires and end of specimens to upper support of wires - be known and maintained. Specimens which have a tendency to warp on heating can be placed in a glass tube or between plates. Tests on such specimens are not considered to be satisfactory. The change in length of materials incident to the heat treatment of the test is recorded as the difference between the room temperature observations before and after the test. Verification of this change is afforded by readings of a micrometer caliper used to secure the length of the specimen before mounting in, and after removal from, the furnace. This value is often of importance in verifying an imperfect annealing of the specimen or establishing the percentage growth or shrinkage due to chemical changes. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.