{"id":6591,"date":"2010-09-18T03:00:29","date_gmt":"2010-09-18T08:00:29","guid":{"rendered":"http:\/\/blogs.scienceforums.net\/swansont\/?p=6591"},"modified":"2010-09-18T03:00:29","modified_gmt":"2010-09-18T08:00:29","slug":"popping-the-kids-balloons","status":"publish","type":"post","link":"http:\/\/blogs.scienceforums.net\/swansont\/archives\/6591","title":{"rendered":"Popping the Kids&#039; Balloons"},"content":{"rendered":"<p>Minister for Home Affairs:  <em>I&#8217;d like to answer this question if I may in two ways. Firstly in my normal voice and then in a kind of silly high-pitched whine<\/em><\/p>\n<p><a href=\"http:\/\/twistedphysics.typepad.com\/cocktail_party_physics\/2010\/09\/helium.html\">Cocktail Party Physics:  helium: a weighty question<\/a><\/p>\n<blockquote><p>One-fifth of the world&#8217;s helium supply is used in MRIs. The typical MRI requires superconducting magnets and, since we haven&#8217;t figured out room-temperature superconductivity yet, they require liquid nitrogen or liquid helium to keep them in the superconducting state.  Most systems use a closed cycle &#8211; helium cools the magnet, warms up in the process, turns to a gas, and is re-liquefied.  A typical MRI magnet, however, requires 1700-2000 liters of liquid helium.  Older models have to be refilled on a timescale from months to years, while newer models advertise that they &#8220;never&#8221; need to be refilled.  (I&#8217;m about to buy a system like that.  We&#8217;ll see how long &#8216;never&#8217; is.)  MRI resolution gets better the larger the magnetic field.  Larger magnetic fields require larger magnets and thus more liquid helium.<\/p><\/blockquote>\n","protected":false},"excerpt":{"rendered":"<p>Minister for Home Affairs: I&#8217;d like to answer this question if I may in two ways. Firstly in my normal voice and then in a kind of silly high-pitched whine Cocktail Party Physics: helium: a weighty question One-fifth of the &hellip; <a href=\"http:\/\/blogs.scienceforums.net\/swansont\/archives\/6591\">Continue reading <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[39],"tags":[],"class_list":["post-6591","post","type-post","status-publish","format-standard","hentry","category-physics"],"_links":{"self":[{"href":"http:\/\/blogs.scienceforums.net\/swansont\/wp-json\/wp\/v2\/posts\/6591","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/blogs.scienceforums.net\/swansont\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/blogs.scienceforums.net\/swansont\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/blogs.scienceforums.net\/swansont\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"http:\/\/blogs.scienceforums.net\/swansont\/wp-json\/wp\/v2\/comments?post=6591"}],"version-history":[{"count":0,"href":"http:\/\/blogs.scienceforums.net\/swansont\/wp-json\/wp\/v2\/posts\/6591\/revisions"}],"wp:attachment":[{"href":"http:\/\/blogs.scienceforums.net\/swansont\/wp-json\/wp\/v2\/media?parent=6591"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/blogs.scienceforums.net\/swansont\/wp-json\/wp\/v2\/categories?post=6591"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/blogs.scienceforums.net\/swansont\/wp-json\/wp\/v2\/tags?post=6591"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}