5.3.2.1

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <title>5.3.2.1</title> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> <script language="JavaScript" type="text/JavaScript">  </script> </head> <body> <div align="justify"> Nanomedicine, Volume I: Basic Capabilities </div> © 1999 <a href="http://www.rfreitas.com">Robert A. Freitas Jr.</a> All Rights Reserved. Robert A. Freitas Jr., Nanomedicine, Volume I: Basic Capabilities, Landes Bioscience, Georgetown, TX, 1999 <hr> <input name="Vol I" type="submit" id="Vol I2" onclick="MM_goToURL('parent','../NMI.htm');return document.MM_returnValue" value="Vol I"> <input name="Backward" type="submit" id="Backward2" onClick="MM_goToURL('parent','5.3.2.htm');return document.MM_returnValue" value="<<<<<"> <input name="Forward" type="submit" id="Forward2" onClick="MM_goToURL('parent','5.3.2.2.htm');return document.MM_returnValue" value=">>>>>"> <input name="Nanomedicine Book Site" type="submit" id="Nanomedicine Book Site" onclick="MM_goToURL('parent','../index.htm');MM_goToURL('parent','../index.htm');return document.MM_returnValue" value="Nanomedicine Book Site"> <input name="Vol IIA" type="submit" id="Vol IIA2" onclick="MM_goToURL('parent','../NMIIA.htm');return document.MM_returnValue" value="Vol IIA"> <input name="Vol IIB" type="submit" id="Vol IIB2" onclick="MM_goToURL('parent','../NMIIB.htm');return document.MM_returnValue" value="Vol IIB"> <input name="Vol III" type="submit" id="Vol III2" onclick="MM_goToURL('parent','../NMIII.htm');return document.MM_returnValue" value="Vol III">   5.3.2.1 Accordion Model <a name="p1"></a>The Accordion Model is characterized by a surface folded in a repeating-W pattern, as in a Japanese fan or butterfly wing pleating; photographic and accordion bellows use what is known in origami* as a "basic fold." Point/line vertices may employ rigid hinges or flexural members.<a href="Refs1200-1299.htm#1251">1251</a> Fold geometry may be double-triangular, triangular-square, or double-square; may consist of segments of varying lengths; or may consist of a series of hinged blocks (<A href="#" onMouseOver="MM_openBrWindow('Figures/5.11.jpg','NanomedicineFigTabWindow','')">Fig. 5.11</A>). This surface remains flexible even near full distension, provided that obtuse angles may be continuously accessed. The main drawback of this model is its likely propensity to surface fouling in vivo due to the large number of concave pockets formed during flexure. <hr> <a name="p2"></a>* The ancient practice of origami (the art of folding three-dimensional objects out of paper without cutting or pasting) has systematically explored the geometries of folded flat sheets;<a href="Refs1100-1199.htm#1102">1102</a>-<a href="Refs1100-1199.htm#1105">1105</a> the mathematics of origami is well-studied.<a href="Refs1100-1199.htm#1106">1106</a>-<a href="Refs1100-1199.htm#1111">1111</a> <hr> <a name="p3"></a>Folding or unfolding may require no sliding surfaces. Treating the model as a simple spherical surface expanding into a watery medium, from <a href="5.3.1.4.htm">Section 5.3.1.4</a> a radial distension velocity of vdrag ~ 0.3 cm/sec may be expected for a 1-micron nanodevice with a 0.1 pW metamorphic power budget. If Nsegment is the total number of segments in a maximally extended surface of area Amax, then for square segments of area L2 and thickness H, Nsegment = Amax / L2 and the fully folded surface has area Amin = L H Nsegment. For L = 10 nm, H = 1 nm, and Amax = 10 micron2 (Nsegment = 105), then Amin = 1 micron2 and a 0.1-pW power budget allows one full-range motion from Amin to Amax in tmotion = (Amax1/2 - Amin1/2) / (2 p1/2 vdrag)~ 0.2 millisec. For the accordion model, areal extensibility earea ~ (L - H) / H = 9.00(900%) in this example.   <input name="Vol I2" type="submit" id="Vol I" onclick="MM_goToURL('parent','../NMI.htm');return document.MM_returnValue" value="Vol I"> <input name="Backward2" type="submit" id="Backward" onClick="MM_goToURL('parent','5.3.2.htm');return document.MM_returnValue" value="<<<<<"> <input name="Forward2" type="submit" id="Forward" onClick="MM_goToURL('parent','5.3.2.2.htm');return document.MM_returnValue" value=">>>>>"> <input name="Nanomedicine Book Site2" type="submit" id="Nanomedicine Book Site2" onclick="MM_goToURL('parent','../index.htm');MM_goToURL('parent','../index.htm');return document.MM_returnValue" value="Nanomedicine Book Site"> <input name="Vol IIA2" type="submit" id="Vol IIA" onclick="MM_goToURL('parent','../NMIIA.htm');return document.MM_returnValue" value="Vol IIA"> <input name="Vol IIB2" type="submit" id="Vol IIB" onclick="MM_goToURL('parent','../NMIIB.htm');return document.MM_returnValue" value="Vol IIB"> <input name="Vol III2" type="submit" id="Vol III" onclick="MM_goToURL('parent','../NMIII.htm');return document.MM_returnValue" value="Vol III"> <div class=Section1></div> <hr> Last updated on 17 February 2003   </body> </html>

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5.3.2.1