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Gang Chen. Barron, Kathleen C., 1982- Massachusetts Institute of Technology. Dept. of Mechanical Engineering. Massachusetts Institute of Technology. Department of Mechanical Engineering 2006-05-15T20:33:35Z 2006-05-15T20:33:35Z 2005 2005 http://hdl.handle.net/1721.1/32836 60689207 Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005. Includes bibliographical references (p. 32). Thermoelectric devices allow for direct conversion between thermal and electrical energy. There applications, however, are severely limited by their inefficiency. A reduction in thermal conductivity of a material potentially enhances its overall thermoelectric performance and can improve the efficiency of thermoelectric devices. Thermal conductivity can be reduced by boundary phonon scattering for materials in which the grain size is comparable to or less than the phonon mean free path. Samples of PbTe and PbSe were prepared by hot pressing nano-size and micro-sized particles and the thermal diffusivity, the Seebeck coefficient, and the electric conductivity of the samples were measured. The samples made from the nano-sized particles showed no reduction in thermal conductivity and no enhancement of thermoelectric properties. It is suspected that the grain growth occurred during the hot pressing stage, resulting in grains sizes larger than the original particle. The grains may have grown substantially larger than the phonon mean free path. Grains of this dimension are not effective at scattering phonons. by Kathleen C. Barron. S.B. 32 p. 1419013 bytes 1417964 bytes application/pdf application/pdf eng Massachusetts Institute of Technology 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. http://dspace.mit.edu/handle/1721.1/7582 Mechanical Engineering. Experimental studies of the thermoelectric properties of microstructured and nanostructured lead salts Thesis application/pdf Publication unknown unknown <Publication xmlns="https://www.openaire.eu/cerif-profile/1.1/" id="359295bc-6e75-4059-b55d-9b5f14ded43a"> <Type xmlns="https://www.openaire.eu/cerif-profile/vocab/COAR_Publication_Types">http://purl.org/coar/resource_type/c_1843</Type> <Language>eng</Language> <Title>Experimental studies of the thermoelectric properties of microstructured and nanostructured lead salts</Title> <PublishedIn> <Publication> </Publication> </PublishedIn> <PublicationDate>2005</PublicationDate> <Authors> <Author> <DisplayName>Barron, Kathleen C., 1982-</DisplayName> <Affiliation> <OrgUnit> </OrgUnit> </Affiliation> </Author> </Authors> <Editors> </Editors> <Publishers> <Publisher> <DisplayName>Massachusetts Institute of Technology</DisplayName> <OrgUnit /> </Publisher> </Publishers> <License>http://dspace.mit.edu/handle/1721.1/7582</License> <Keyword>Mechanical Engineering.</Keyword> <Abstract>Thermoelectric devices allow for direct conversion between thermal and electrical energy. There applications, however, are severely limited by their inefficiency. A reduction in thermal conductivity of a material potentially enhances its overall thermoelectric performance and can improve the efficiency of thermoelectric devices. Thermal conductivity can be reduced by boundary phonon scattering for materials in which the grain size is comparable to or less than the phonon mean free path. Samples of PbTe and PbSe were prepared by hot pressing nano-size and micro-sized particles and the thermal diffusivity, the Seebeck coefficient, and the electric conductivity of the samples were measured. The samples made from the nano-sized particles showed no reduction in thermal conductivity and no enhancement of thermoelectric properties. It is suspected that the grain growth occurred during the hot pressing stage, resulting in grains sizes larger than the original particle. The grains may have grown substantially larger than the phonon mean free path. Grains of this dimension are not effective at scattering phonons.</Abstract> <Access xmlns="http://purl.org/coar/access_right" > </Access> </Publication>