<?xml version="1.0" encoding="UTF-8"?><?xml-stylesheet type="text/xsl" href="static/style.xsl"?><OAI-PMH xmlns="http://www.openarchives.org/OAI/2.0/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/ http://www.openarchives.org/OAI/2.0/OAI-PMH.xsd"><responseDate>2026-09-19T22:37:16Z</responseDate><request verb="GetRecord" identifier="oai:dspace.mit.edu:1721.1/31147" metadataPrefix="dim">https://dspace.mit.edu/server/oai/request</request><GetRecord><record><header><identifier>oai:dspace.mit.edu:1721.1/31147</identifier><datestamp>2022-01-13T07:54:23Z</datestamp><setSpec>com_1721.1_7582</setSpec><setSpec>com_1721.1_7581</setSpec><setSpec>col_1721.1_131023</setSpec></header><metadata><dim:dim xmlns:dim="http://www.dspace.org/xmlns/dspace/dim" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:doc="http://www.lyncode.com/xoai" xsi:schemaLocation="http://www.dspace.org/xmlns/dspace/dim http://www.dspace.org/schema/dim.xsd">
   <dim:field mdschema="dc" element="contributor" qualifier="advisor" lang="en_US">Franz-Josef Ulm.</dim:field>
   <dim:field mdschema="dc" element="contributor" qualifier="author" lang="en_US">Bobko, Christopher Philip, 1981-</dim:field>
   <dim:field mdschema="dc" element="contributor" qualifier="other" lang="en_US">Massachusetts Institute of Technology. Dept. of Civil and Environmental Engineering.</dim:field>
   <dim:field mdschema="dc" element="contributor" qualifier="department">Massachusetts Institute of Technology. Department of Civil and Environmental Engineering</dim:field>
   <dim:field mdschema="dc" element="date" qualifier="accessioned">2006-02-02T18:52:48Z</dim:field>
   <dim:field mdschema="dc" element="date" qualifier="available">2006-02-02T18:52:48Z</dim:field>
   <dim:field mdschema="dc" element="date" qualifier="copyright" lang="en_US">2005</dim:field>
   <dim:field mdschema="dc" element="date" qualifier="issued" lang="en_US">2005</dim:field>
   <dim:field mdschema="dc" element="identifier" qualifier="uri">http://hdl.handle.net/1721.1/31147</dim:field>
   <dim:field mdschema="dc" element="identifier" qualifier="oclc" lang="en_US">61186160</dim:field>
   <dim:field mdschema="dc" element="description" lang="en_US">Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2005.</dim:field>
   <dim:field mdschema="dc" element="description" lang="en_US">Includes bibliographical references (p. 183-189).</dim:field>
   <dim:field mdschema="dc" element="description" qualifier="abstract" lang="en_US">The diversity of sandstones and sandstone properties that exist in nature pose a significant problem for engineers who deal with these materials, whether in oil well exploration and exploitation or art and architectural conservation. The solution proposed in this thesis takes a highly reductionist approach to the problem. Properties of the sandstone material are first reduced to material invariant properties of the material phases present in sandstone. These are universal constants which do not vary from one sample to the other. From these material invariants, it is then possible to 'nanoengineer' the properties of a specific sandstone sample based only on a few easily measured properties - the volume fractions of the material phases. To help identify material invariant phases and reconstruct microstructure, a multi-scale think model for sandstone is developed from ESEM images as well as from the results of mineralogy, grain size, and porosimetry experiments. A nanoindentation campaign is performed to characterize sandstones at multiple scales and an innovative technique is used to separate the various indentation responses that can occur on a heterogeneous composite. Material invariant phase properties are obtained for both the sand grains and the clay minerals. A new technique for estimating volume fractions of composite materials using nanoindentation is developed and verified. Clay stiffnesses are found to be highly dependent on microstructure rather than on mineralogy, and material invariant properties are proposed. A comparison of models to estimate elastic and poro-elastic properties reveal shortcomings that motivate the development of a new predictive model.</dim:field>
   <dim:field mdschema="dc" element="description" qualifier="abstract" lang="en_US">(cont.) A multi-scale model employing a self consistent scheme and a double-porosity model is suggested and applied with excellent results predicting poroelastic properties. This model permits the 'nanoengineering' of a specific sandstone sample based only on the volume fractions of the material phases.</dim:field>
   <dim:field mdschema="dc" element="description" qualifier="statementofresponsibility" lang="en_US">by Christopher Philip Bobko.</dim:field>
   <dim:field mdschema="dc" element="description" qualifier="degree" lang="en_US">S.M.</dim:field>
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   <dim:field mdschema="dc" element="publisher" lang="en_US">Massachusetts Institute of Technology</dim:field>
   <dim:field mdschema="dc" element="rights" lang="en_US">M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.</dim:field>
   <dim:field mdschema="dc" element="rights" qualifier="uri">http://dspace.mit.edu/handle/1721.1/7582</dim:field>
   <dim:field mdschema="dc" element="subject" lang="en_US">Civil and Environmental Engineering.</dim:field>
   <dim:field mdschema="dc" element="title" lang="en_US">Material invariant properties and reconstruction of microstructure of sandstones by nanoindentation and microporoelastic analysis</dim:field>
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   	&lt;Title>Material invariant properties and reconstruction of microstructure of sandstones by nanoindentation and microporoelastic analysis&lt;/Title>
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   	&lt;Abstract>The diversity of sandstones and sandstone properties that exist in nature pose a significant problem for engineers who deal with these materials, whether in oil well exploration and exploitation or art and architectural conservation. The solution proposed in this thesis takes a highly reductionist approach to the problem. Properties of the sandstone material are first reduced to material invariant properties of the material phases present in sandstone. These are universal constants which do not vary from one sample to the other. From these material invariants, it is then possible to &amp;apos;nanoengineer&amp;apos; the properties of a specific sandstone sample based only on a few easily measured properties - the volume fractions of the material phases. To help identify material invariant phases and reconstruct microstructure, a multi-scale think model for sandstone is developed from ESEM images as well as from the results of mineralogy, grain size, and porosimetry experiments. A nanoindentation campaign is performed to characterize sandstones at multiple scales and an innovative technique is used to separate the various indentation responses that can occur on a heterogeneous composite. Material invariant phase properties are obtained for both the sand grains and the clay minerals. A new technique for estimating volume fractions of composite materials using nanoindentation is developed and verified. Clay stiffnesses are found to be highly dependent on microstructure rather than on mineralogy, and material invariant properties are proposed. A comparison of models to estimate elastic and poro-elastic properties reveal shortcomings that motivate the development of a new predictive model.&lt;/Abstract>
   	&lt;Abstract>(cont.) A multi-scale model employing a self consistent scheme and a double-porosity model is suggested and applied with excellent results predicting poroelastic properties. This model permits the &amp;apos;nanoengineering&amp;apos; of a specific sandstone sample based only on the volume fractions of the material phases.&lt;/Abstract>
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