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Vital Spaces
| Article
# : |
15892 |
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Section : |
NATURAL SCIENCE
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| Issue
Date : |
1 / 1989 |
2,972 Words |
| Author
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Douglas Smith and Neal Singer
Douglas Smith is director of the National Science Foundation's
Center for Micro-Engineered Ceramics at the University of New
Mexico, and a UNM associate professor of chemical and nuclear
engineering. Professor Smith has published over 50 articles
on pore structure characteristics.
Neal Singer is a staff writer at the University of New
Mexico's public affairs department. His articles on science
and other subjects have appeared in a wide variety of
magazines and newspapers. |
Anyone who takes the grand perspective of considering the universe a single object, like a blanket or a cheese, would have to conclude that in spite of its mass, the universe is more porous than solid. But humanity is preoccupied with objects rather than voids, and until modern times, for good reason. The caged tiger takes up less room than the empty space behind bars with him, but it is the tiger who carries the threat of action.
However, as scientists probe finer and finer levels of the emptiness that permeates almost every known material, a new science has come into increased prominence. The science of porosity deals with pores, or enclosed empty spaces, of materials, and promises to change the inanimate world as completely as control of DNA promises to change the biological one. By controlling the process of the creation of interior emptiness--its size, its shape, its regularity--an inanimate world can be created that begins at the atomic level to serve humanity's needs.
Consider the importance of pores in everyday life. On the most commonplace level, bakery companies improve the texture of their product by controlling the size of pores by using different yeasts. The rapid dissolution of instant coffee and the mixing of frozen juices depend in large part upon the tiny spaces--technically, pores--that allow water to penetrate as quickly as possible.
Felt-tipped pens use materials permeated by pores that are just big enough to transmit molecules of ink through capillary action, yet not so big that the ink streams through to become a blot upon paper. The rate at which oil and gas is retrieved from the earth, as well as the percentage of it recovered, also depends largely on the regularity of the pore structure of the host formation.
Radioactive storage, similarly, is best accomplished by materials like salt and compacted volcanic ash--composed of the smallest and fewest pores, so that passage of radioactivity through the storage medium is minimized.
Packing Powders
Modern interest in porosity has become even more exacting than these examples suggest. The trend--sparked not by dramatic discoveries but through the evolutionary result of the work of many minds--has tended steadily toward creating material with desired pore characteristics, rather than merely making do with what
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