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  5.     <title>UTas ePrints - Chemical treatment of backsawn Tasmanian Oak with Polyethylene Glycol (PEG) prior to drying</title>
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  13.     <meta content="Ralph, John" name="eprints.creators_name" />
  14. <meta content="thesis" name="eprints.type" />
  15. <meta content="2007-07-19" name="eprints.datestamp" />
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  18. <meta content="Chemical treatment of
  19. backsawn Tasmanian Oak
  20. with Polyethylene Glycol (PEG) prior to drying" name="eprints.title" />
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  25. <meta content="PEG, polyethlene glycol, Tasmania, tasmanian oak, timber, treatment" name="eprints.keywords" />
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  27. <meta content="A series of experiments was conducted with the view of obtaining baseline information
  28. on the use of polyethylene glycol (PEG) on Tasmanian Oak for the purpose of improving
  29. the quality of the seasoned structural timber product. Tasmanian Oak is the marketing
  30. name for a triad of Tasmanian-grown eucalypt species (E. delegatensis, E. obliqua, and E.
  31. regnans). Incubation of freshly-milled timber in aqueous PEG solutions prior to
  32. seasoning follows on from investigations in northern hemispheric timber species such as
  33. hoop pine and spruce in the middle of the 20th Century.
  34. PEG penetrates freshly sawn Tasmanian Oak in a manner which is considerate of
  35. incubation time, temperature, PEG molecular weight/size and timber density.
  36. Histological examination indicated that PEG penetrated completely throughout the
  37. structure of the wood substance in three orientations (transverse, radial and tangential).
  38. During air-drying of PEG soaked timber, further migration of PEG into Tasmanian Oak is
  39. negligible. The rate of moisture content loss in Tasmanian Oak was shown to be retarded
  40. by PEG pre-treatment although the ability to prevent moisture loss was not concomitant
  41. with dimensional stability. An investigation to explain the change in rate of moisture loss
  42. examined effects on the thermodynamic property, water activity. Results indicated that a
  43. change in solution water activity could partly expain changes in the rate of moisture
  44. content loss, but more research is required to better divine this relationship.
  45. Shrinkage in Tasmanian Oak was reduced after treatment with aqueous PEG 400
  46. solutions at or above 30% (v/v), with a greater percentage reduction in tangential
  47. shrinkage compared to reduction in radial shrinkage. This is significant as backsawn (a.k.a. flatsawn) timber, with its broader tangential face, was in particular focus. The
  48. reduction in shrinkage was consistent with PEG concentration in the incubating medium.
  49. A decrease in the formation of drying defect, such as surface and internal checking
  50. accompanied the improvement in keeping sawn dimensions.
  51. Backsawn Tasmanian Oak obtained from young trees (less than 20 years) from plantation
  52. resource presents a challenging profile for commercial timber drying and will become
  53. more prevalent as the logging of old-growth forests is phased out. Timber seasoners may
  54. be faced with options of longer drying times or lower yields due to drying defect unless a
  55. method can be developed to provide added protection to the sawn timber product during
  56. drying. At this stage, pre-treatment of Tasmanian Oak with PEG shows the hallmarks of
  57. providing a solution to this emerging dilemma." name="eprints.abstract" />
  58. <meta content="2006-12" name="eprints.date" />
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  67. <meta content="Ralph, John (2006) Chemical treatment of backsawn Tasmanian Oak with Polyethylene Glycol (PEG) prior to drying. PhD thesis, University of Tasmania." name="eprints.citation" />
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  76. <meta content="Chemical treatment of
  77. backsawn Tasmanian Oak
  78. with Polyethylene Glycol (PEG) prior to drying" name="DC.title" />
  79. <meta content="Ralph, John" name="DC.creator" />
  80. <meta content="270402 Plant Physiology" name="DC.subject" />
  81. <meta content="270400 Botany" name="DC.subject" />
  82. <meta content="A series of experiments was conducted with the view of obtaining baseline information
  83. on the use of polyethylene glycol (PEG) on Tasmanian Oak for the purpose of improving
  84. the quality of the seasoned structural timber product. Tasmanian Oak is the marketing
  85. name for a triad of Tasmanian-grown eucalypt species (E. delegatensis, E. obliqua, and E.
  86. regnans). Incubation of freshly-milled timber in aqueous PEG solutions prior to
  87. seasoning follows on from investigations in northern hemispheric timber species such as
  88. hoop pine and spruce in the middle of the 20th Century.
  89. PEG penetrates freshly sawn Tasmanian Oak in a manner which is considerate of
  90. incubation time, temperature, PEG molecular weight/size and timber density.
  91. Histological examination indicated that PEG penetrated completely throughout the
  92. structure of the wood substance in three orientations (transverse, radial and tangential).
  93. During air-drying of PEG soaked timber, further migration of PEG into Tasmanian Oak is
  94. negligible. The rate of moisture content loss in Tasmanian Oak was shown to be retarded
  95. by PEG pre-treatment although the ability to prevent moisture loss was not concomitant
  96. with dimensional stability. An investigation to explain the change in rate of moisture loss
  97. examined effects on the thermodynamic property, water activity. Results indicated that a
  98. change in solution water activity could partly expain changes in the rate of moisture
  99. content loss, but more research is required to better divine this relationship.
  100. Shrinkage in Tasmanian Oak was reduced after treatment with aqueous PEG 400
  101. solutions at or above 30% (v/v), with a greater percentage reduction in tangential
  102. shrinkage compared to reduction in radial shrinkage. This is significant as backsawn (a.k.a. flatsawn) timber, with its broader tangential face, was in particular focus. The
  103. reduction in shrinkage was consistent with PEG concentration in the incubating medium.
  104. A decrease in the formation of drying defect, such as surface and internal checking
  105. accompanied the improvement in keeping sawn dimensions.
  106. Backsawn Tasmanian Oak obtained from young trees (less than 20 years) from plantation
  107. resource presents a challenging profile for commercial timber drying and will become
  108. more prevalent as the logging of old-growth forests is phased out. Timber seasoners may
  109. be faced with options of longer drying times or lower yields due to drying defect unless a
  110. method can be developed to provide added protection to the sawn timber product during
  111. drying. At this stage, pre-treatment of Tasmanian Oak with PEG shows the hallmarks of
  112. providing a solution to this emerging dilemma." name="DC.description" />
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  238.     <h1 class="ep_tm_pagetitle">Chemical treatment of backsawn Tasmanian Oak with Polyethylene Glycol (PEG) prior to drying</h1>
  239.     <p style="margin-bottom: 1em" class="not_ep_block"><span class="person_name">Ralph, John</span> (2006) <xhtml:em>Chemical treatment of backsawn Tasmanian Oak with Polyethylene Glycol (PEG) prior to drying.</xhtml:em> PhD thesis, University of Tasmania.</p><p style="margin-bottom: 1em" class="not_ep_block"></p><table style="margin-bottom: 1em" class="not_ep_block"><tr><td valign="top" style="text-align:center"><a onmouseover="EPJS_ShowPreview( event, 'doc_preview_1580' );" href="http://eprints.utas.edu.au/1222/1/JRalphthesis_front.pdf" onmouseout="EPJS_HidePreview( event, 'doc_preview_1580' );"><img alt="[img]" src="http://eprints.utas.edu.au/style/images/fileicons/application_pdf.png" class="ep_doc_icon" border="0" /></a><div class="ep_preview" id="doc_preview_1580"><table><tr><td><img alt="" src="http://eprints.utas.edu.au/1222/thumbnails/1/preview.png" class="ep_preview_image" border="0" /><div class="ep_preview_title">Preview</div></td></tr></table></div></td><td valign="top"><a href="http://eprints.utas.edu.au/1222/1/JRalphthesis_front.pdf"><span class="ep_document_citation">PDF (Front Matter)</span></a> - Requires a PDF viewer<br />67Kb</td></tr><tr><td valign="top" style="text-align:center"><a onmouseover="EPJS_ShowPreview( event, 'doc_preview_1581' );" href="http://eprints.utas.edu.au/1222/2/JRalphthesis_complete.pdf" onmouseout="EPJS_HidePreview( event, 'doc_preview_1581' );"><img alt="[img]" src="http://eprints.utas.edu.au/style/images/fileicons/application_pdf.png" class="ep_doc_icon" border="0" /></a><div class="ep_preview" id="doc_preview_1581"><table><tr><td><img alt="" src="http://eprints.utas.edu.au/1222/thumbnails/2/preview.png" class="ep_preview_image" border="0" /><div class="ep_preview_title">Preview</div></td></tr></table></div></td><td valign="top"><a href="http://eprints.utas.edu.au/1222/2/JRalphthesis_complete.pdf"><span class="ep_document_citation">PDF (Whole Thesis)</span></a> - Requires a PDF viewer<br />2934Kb</td></tr><tr><td valign="top" style="text-align:center"><a onmouseover="EPJS_ShowPreview( event, 'doc_preview_1582' );" href="http://eprints.utas.edu.au/1222/3/JRalphAppendix1.pdf" onmouseout="EPJS_HidePreview( event, 'doc_preview_1582' );"><img alt="[img]" src="http://eprints.utas.edu.au/style/images/fileicons/application_pdf.png" class="ep_doc_icon" border="0" /></a><div class="ep_preview" id="doc_preview_1582"><table><tr><td><img alt="" src="http://eprints.utas.edu.au/1222/thumbnails/3/preview.png" class="ep_preview_image" border="0" /><div class="ep_preview_title">Preview</div></td></tr></table></div></td><td valign="top"><a href="http://eprints.utas.edu.au/1222/3/JRalphAppendix1.pdf"><span class="ep_document_citation">PDF (Appendix 1)</span></a> - Requires a PDF viewer<br />354Kb</td></tr><tr><td valign="top" style="text-align:center"><a onmouseover="EPJS_ShowPreview( event, 'doc_preview_1583' );" href="http://eprints.utas.edu.au/1222/4/JRalphAppendix2_1.pdf" onmouseout="EPJS_HidePreview( event, 'doc_preview_1583' );"><img alt="[img]" src="http://eprints.utas.edu.au/style/images/fileicons/application_pdf.png" class="ep_doc_icon" border="0" /></a><div class="ep_preview" id="doc_preview_1583"><table><tr><td><img alt="" src="http://eprints.utas.edu.au/1222/thumbnails/4/preview.png" class="ep_preview_image" border="0" /><div class="ep_preview_title">Preview</div></td></tr></table></div></td><td valign="top"><a href="http://eprints.utas.edu.au/1222/4/JRalphAppendix2_1.pdf"><span class="ep_document_citation">PDF (Appendix 2.1)</span></a> - Requires a PDF viewer<br />273Kb</td></tr><tr><td valign="top" style="text-align:center"><a onmouseover="EPJS_ShowPreview( event, 'doc_preview_1584' );" href="http://eprints.utas.edu.au/1222/5/JRalphAppendix2_2.pdf" onmouseout="EPJS_HidePreview( event, 'doc_preview_1584' );"><img alt="[img]" src="http://eprints.utas.edu.au/style/images/fileicons/application_pdf.png" class="ep_doc_icon" border="0" /></a><div class="ep_preview" id="doc_preview_1584"><table><tr><td><img alt="" src="http://eprints.utas.edu.au/1222/thumbnails/5/preview.png" class="ep_preview_image" border="0" /><div class="ep_preview_title">Preview</div></td></tr></table></div></td><td valign="top"><a href="http://eprints.utas.edu.au/1222/5/JRalphAppendix2_2.pdf"><span class="ep_document_citation">PDF (Appendix 2.2)</span></a> - Requires a PDF viewer<br />525Kb</td></tr><tr><td valign="top" style="text-align:center"><a onmouseover="EPJS_ShowPreview( event, 'doc_preview_1585' );" href="http://eprints.utas.edu.au/1222/6/JRalphAppendix2_3.pdf" onmouseout="EPJS_HidePreview( event, 'doc_preview_1585' );"><img alt="[img]" src="http://eprints.utas.edu.au/style/images/fileicons/application_pdf.png" class="ep_doc_icon" border="0" /></a><div class="ep_preview" id="doc_preview_1585"><table><tr><td><img alt="" src="http://eprints.utas.edu.au/1222/thumbnails/6/preview.png" class="ep_preview_image" border="0" /><div class="ep_preview_title">Preview</div></td></tr></table></div></td><td valign="top"><a href="http://eprints.utas.edu.au/1222/6/JRalphAppendix2_3.pdf"><span class="ep_document_citation">PDF (Appendix 2.3)</span></a> - Requires a PDF viewer<br />515Kb</td></tr><tr><td valign="top" style="text-align:center"><a onmouseover="EPJS_ShowPreview( event, 'doc_preview_1586' );" href="http://eprints.utas.edu.au/1222/7/JRalphAppendix3.pdf" onmouseout="EPJS_HidePreview( event, 'doc_preview_1586' );"><img alt="[img]" src="http://eprints.utas.edu.au/style/images/fileicons/application_pdf.png" class="ep_doc_icon" border="0" /></a><div class="ep_preview" id="doc_preview_1586"><table><tr><td><img alt="" src="http://eprints.utas.edu.au/1222/thumbnails/7/preview.png" class="ep_preview_image" border="0" /><div class="ep_preview_title">Preview</div></td></tr></table></div></td><td valign="top"><a href="http://eprints.utas.edu.au/1222/7/JRalphAppendix3.pdf"><span class="ep_document_citation">PDF (Appendix 3)</span></a> - Requires a PDF viewer<br />324Kb</td></tr></table><div class="not_ep_block"><h2>Abstract</h2><p style="padding-bottom: 16px; text-align: left; margin: 1em auto 0em auto">A series of experiments was conducted with the view of obtaining baseline information
  240. on the use of polyethylene glycol (PEG) on Tasmanian Oak for the purpose of improving
  241. the quality of the seasoned structural timber product. Tasmanian Oak is the marketing
  242. name for a triad of Tasmanian-grown eucalypt species (E. delegatensis, E. obliqua, and E.
  243. regnans). Incubation of freshly-milled timber in aqueous PEG solutions prior to
  244. seasoning follows on from investigations in northern hemispheric timber species such as
  245. hoop pine and spruce in the middle of the 20th Century.
  246. PEG penetrates freshly sawn Tasmanian Oak in a manner which is considerate of
  247. incubation time, temperature, PEG molecular weight/size and timber density.
  248. Histological examination indicated that PEG penetrated completely throughout the
  249. structure of the wood substance in three orientations (transverse, radial and tangential).
  250. During air-drying of PEG soaked timber, further migration of PEG into Tasmanian Oak is
  251. negligible. The rate of moisture content loss in Tasmanian Oak was shown to be retarded
  252. by PEG pre-treatment although the ability to prevent moisture loss was not concomitant
  253. with dimensional stability. An investigation to explain the change in rate of moisture loss
  254. examined effects on the thermodynamic property, water activity. Results indicated that a
  255. change in solution water activity could partly expain changes in the rate of moisture
  256. content loss, but more research is required to better divine this relationship.
  257. Shrinkage in Tasmanian Oak was reduced after treatment with aqueous PEG 400
  258. solutions at or above 30% (v/v), with a greater percentage reduction in tangential
  259. shrinkage compared to reduction in radial shrinkage. This is significant as backsawn (a.k.a. flatsawn) timber, with its broader tangential face, was in particular focus. The
  260. reduction in shrinkage was consistent with PEG concentration in the incubating medium.
  261. A decrease in the formation of drying defect, such as surface and internal checking
  262. accompanied the improvement in keeping sawn dimensions.
  263. Backsawn Tasmanian Oak obtained from young trees (less than 20 years) from plantation
  264. resource presents a challenging profile for commercial timber drying and will become
  265. more prevalent as the logging of old-growth forests is phased out. Timber seasoners may
  266. be faced with options of longer drying times or lower yields due to drying defect unless a
  267. method can be developed to provide added protection to the sawn timber product during
  268. drying. At this stage, pre-treatment of Tasmanian Oak with PEG shows the hallmarks of
  269. providing a solution to this emerging dilemma.</p></div><table style="margin-bottom: 1em" cellpadding="3" class="not_ep_block" border="0"><tr><th valign="top" class="ep_row">Item Type:</th><td valign="top" class="ep_row">Thesis (PhD)</td></tr><tr><th valign="top" class="ep_row">Additional Information:</th><td valign="top" class="ep_row">  </td></tr><tr><th valign="top" class="ep_row">Keywords:</th><td valign="top" class="ep_row">PEG, polyethlene glycol, Tasmania, tasmanian oak, timber, treatment</td></tr><tr><th valign="top" class="ep_row">Subjects:</th><td valign="top" class="ep_row"><a href="http://eprints.utas.edu.au/view/subjects/270402.html">270000 Biological Sciences &gt; 270400 Botany &gt; 270402 Plant Physiology</a><br /><a href="http://eprints.utas.edu.au/view/subjects/270400.html">270000 Biological Sciences &gt; 270400 Botany</a></td></tr><tr><th valign="top" class="ep_row">ID Code:</th><td valign="top" class="ep_row">1222</td></tr><tr><th valign="top" class="ep_row">Deposited By:</th><td valign="top" class="ep_row"><span class="ep_name_citation"><span class="person_name">UTas Digital Archives Librarian</span></span></td></tr><tr><th valign="top" class="ep_row">Deposited On:</th><td valign="top" class="ep_row">19 Jul 2007</td></tr><tr><th valign="top" class="ep_row">Last Modified:</th><td valign="top" class="ep_row">09 Jan 2008 02:30</td></tr><tr><th valign="top" class="ep_row">ePrint Statistics:</th><td valign="top" class="ep_row"><a target="ePrintStats" href="/es/index.php?action=show_detail_eprint;id=1222;">View statistics for this ePrint</a></td></tr></table><p align="right">Repository Staff Only: <a href="http://eprints.utas.edu.au/cgi/users/home?screen=EPrint::View&amp;eprintid=1222">item control page</a></p>
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