Cryogenics And The Future :: essays research papers

cryogeny and the Future     Cryogenics is a study that is of great importance to the human induce andhas been a major project for engineers for the last 100 years. Cryogenics,which is derived from the Greek word kryos meaning " nippy Cold," is the study ofmatter at low temperatures. However low is not even the right word for thetemperatures involved in cryogenics, seeing as the highest temperature dealtwith in cryogenics is 100 (C (-148 (F) and the lowest temperature used, is theunattainable temperature -273.15 (C (-459.67 (F). Also, when speaking ofcryogenics, the terms Celsius and Fahrenheit are rarely used. Insteadscientists use a opposite measurement called the Kelvin (K). The Kelvin scalefor Cryogenics goes from 173 K to a fraction of a Kelvin above absolute zero.There are also two main sciences used in cryogenics, and they areSuperconductivity and Superfluidity.     Cryogenics first came about in 1877, when a Swiss Physicist named RasulPictet and a French Engineer named Louis P. Cailletet liquefied oxygen for thefirst time. Cailletet created liquid oxygen in his lab using a process cognize asadiabatic expansion, which is a "thermodynamic process in which the temperatureof a gas is expand without adding or extracting heat from the gas or thesurrounding system"(Vance 26). At the same time Pictet used the "Joule-ThompsonEffect," a thermodynamic process that states that the "temperature of a fluid isreduced in a process involving expansion below a certain temperature andpressure"(McClintock 4). After Cailletet and Pictet, a third method, known ascascading, was developed by Karol S. Olszewski and Zygmut von Wroblewski inPoland. At this point in history Oxygen was now able to be liquefied at 90 K,then soon after liquid Nitrogen was obtained at 77 K, and because of theseadvancements scientist all over the world began competing in a race to lower thetemperature of matter to Absolute Z ero (0 K) Vance, 1-10.     Then in 1898, throng DeWar mad a major advance when he succeeded inliquifying total heat at 20 K. The reason this advance was so spectacular wasthat at 20 K hydrogen is also boiling, and this presented a very operosehandling and transshipment center problem. DeWar solved this problem by inventing a double-walled storage container known as the DeWar flask, which could contain and holdthe liquid hydrogen for a few days. However, at this time scientists realizedthat if they were going to make whatever more advances they would have to have betterholding containers. So, scientists came up with insulant techniques that westill use today.