<?xml version='1.0' encoding='utf-8'?>
<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:contributor>D. D. Eberl</dc:contributor>
  <dc:creator>D. E. Kile</dc:creator>
  <dc:date>2003</dc:date>
  <dc:description>&lt;p&gt;&lt;span&gt;rystal growth experiments were conducted using potassium alum and calcite crystals in aqueous&lt;/span&gt;&lt;span&gt;solution under both non-stirred and stirred conditions to elucidate the mechanism for size-dependent&lt;/span&gt;&lt;span&gt;(proportionate) and size-independent (constant) crystal growth. Growth by these two laws can be dis-&lt;/span&gt;&lt;span&gt;tinguished from each other because the &lt;/span&gt;&lt;span&gt;r&lt;/span&gt;&lt;span&gt;elative&lt;/span&gt;&lt;span&gt;size difference among crystals is maintained during&lt;/span&gt;&lt;span&gt;proportionate growth, leading to a constant crystal size variance (&lt;/span&gt;&lt;span&gt;b&lt;/span&gt;&lt;span&gt;2&lt;/span&gt;&lt;span&gt;) for a crystal size distribution&lt;/span&gt;&lt;span&gt;(CSD) as the mean size increases. The &lt;/span&gt;&lt;span&gt;absolute&lt;/span&gt;&lt;span&gt;size difference among crystals is maintained during&lt;/span&gt;&lt;span&gt;constant growth, resulting in a decrease in size variance. Results of these experiments show that for&lt;/span&gt;&lt;span&gt;centimeter-sized alum crystals, proportionate growth occurs in stirred systems, whereas constant growth&lt;/span&gt;&lt;span&gt;occurs in non-stirred systems. Accordingly, the mechanism for proportionate growth is hypothesized&lt;/span&gt;&lt;span&gt;to be related to the supply of reactants to the crystal surface by advection, whereas constant growth is&lt;/span&gt;&lt;span&gt;related to supply by diffusion. Paradoxically, micrometer-sized calcite crystals showed proportionate&lt;/span&gt;&lt;span&gt;growth both in stirred and in non-stirred systems. Such growth presumably results from the effects of&lt;/span&gt;&lt;span&gt;convection and Brownian motion, which promote an advective environment and hence proportionate&lt;/span&gt;&lt;span&gt;growth for minute crystals in non-stirred systems, thereby indicating the importance of solution veloc-&lt;/span&gt;&lt;span&gt;ity relative to crystal size. Calcite crystals grown in gels, where fluid motion was minimized, showed&lt;/span&gt;&lt;span&gt;evidence for constant, diffusion-controlled growth. Additional investigations of CSDs of naturally&lt;/span&gt;&lt;span&gt;occurring crystals indicate that proportionate growth is by far the most common growth law, thereby&lt;/span&gt;&lt;span&gt;suggesting that ad&lt;/span&gt;&lt;span&gt;ection, rather than diffusion, is the dominant process for supplying reactants to crystal surfaces.&amp;nbsp;&lt;/span&gt;&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.2138/am-2003-1014</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>Walter de Gruyter</dc:publisher>
  <dc:title>On the origin of size-dependent and size-independent crystal growth: Influence of advection and diffusion</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>