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About RF Cafe
1996 - 2022
BSEE - KB3UON
RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The Internet was still largely an unknown entity at the time and not much was available in the form of WYSIWYG ...
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In a Scientific American article titled "Elemental Urgency," Jennifer Hackett reported on a paper published in 2013 by Yale University's Thomas Graedel et al regarding the availability (or unavailability) of the raw elements - and suitable substitutes - used extensively in modern manufacturing. Unlike half a century ago when most products were made from relatively common and easily obtainable elements like lead, iron, tin, nickel, aluminum, carbon, zinc, silicon, and even silver and gold, many more elements are now regularly included in mass manufacturing processes. Rhenium (Re), used in high strength, temperature alloys to applications like jet engine turbine blades and as a catalyst in chemical processes, is one of the most critically rated elements for uniqueness. Ditto for titanium. Yttrium (Y), used in the familiar YIG oscillator and YAG laser, is another critical element. Keep in mind that this chart rates elements not solely according to scarcity, but how critical they are in processes where no other element can be substituted in the event of a shortage. Lead (Pb) is a clear example of an element that is abundantly available, but the materials in which it is used cannot be easily replaced with another element. Compounding the issue is the rate at which product manufacturing is increasing over time, which requires a rapidly expanding availability of raw materials.
Whereas a paid SciAm subscription is required to view Graedel's "The Periodic Table of Substitute Performance" graphic (thumbnail to the upper right), the original is freely accessed in "On the materials basis of modern society." This abstract statement in the paper sums up the situation alarmingly well:
"It is indisputable that modern life is enabled by the use of materials in its technologies. Those technologies do many things very well, largely because each material is used for purposes to which it is exquisitely fitted. The result over time has been a steady increase in product performance. We show that this materials complexity has markedly increased in the past half-century and that elemental life cycle analyses characterize rates of recycling and loss. A further concern is that of possible scarcity of some of the elements as their use increases. Should materials availability constraints occur, the use of substitute materials comes to mind. We studied substitution potential by generating a comprehensive summary of potential substitutes for 62 different metals in all their major uses and of the performance of the substitutes in those applications. As we show herein, for a dozen different metals, the potential substitutes for their major uses are either inadequate or appear not to exist at all. Further, for not 1 of the 62 metals are exemplary substitutes available for all major uses."
You might be interested in a report I wrote in 2011 titled, "Afghanistan's Buried Riches - Rare Earths & More," that helped to shed light on why it is countries are so invested (literally) in obtaining access to even the most dangerous regions on Earth in order to mine valuable elements and minerals. It is no doubt a large part of the reason troops are still there after more than a decade - they are protecting the investments of political donor companies (to Democrat, Republican, and Independent).
These items are an archive of past Topical Smorgasbord items that have appeared on the RF Cafe homepage. In keeping with the "cafe" genre, these tidbits of information are truly a smorgasbord of topics. They all pertain to topics that are related to the general engineering and science theme of RF Cafe. Note: There is also a huge collection of my 'Factoids' (aka 'Kirt's Cogitations') that might interest you as well.
Posted May 31, 2016