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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
141

The effect of uniaxial orientation upon the structural properties of polvaniline films

Laughlin, Paul Jonathan January 1996 (has links)
The effects of elongation upon the structural and electronic properties of the conducting polymer polyaniline have been investigated. In particular, the properties of high molecular weight (ca. 150 000 Daltons) polyaniline have been examined, and the effects of increased molecular weight assessed. A method has been found to elongate the emeraldine base (EB) form up to 700% (l/l(_o)=8). This induces partial molecular alignment in the polymer which, upon doping, exhibits electrical conductivity of up to 700 Scm(_-1) and electrical anisotropy of almost 4.The mechanical properties of high molecular weight emeraldine base have been investigated as a function of elongation. The breaking stress has been observed to increase by almost one order of magnitude for a 500% elongated film compared with its unoriented counterpart. The breaking strain is found to decrease initially with increasing elongation, though no noticeable change is evident for samples elongated to more than 300%. Similarly, Young's modulus increases by a factor of 2 with increased elongation, but above 300% remains approximately constant. The behaviour has been interpreted in terms of the crystalline fraction of the samples. X-ray diffraction experiments have enabled the crystalline fraction of emeraldine base and emeraldine salt (ES) to be assessed. 300% elongated EB samples exhibit increased crystalhnity compared with as-cast samples. However, no further increase in crystallmity is evident for 600% elongated samples. Unoriented ES samples have a crystalline fraction of approximately 0.3. The crystallinity of 300% and 600% elongated ES samples is slightly less than for unoriented ES. The polarised reflectance spectra of EB and ES have been measured in the region 0.5- 5.6 eV. The results show increased optical anisotropy with increasing elongation for EB samples, but no change in anisotropy for ES samples above 300% elongation. A Kramers-Kronig analysis of the reflectance data reveals near metallic behaviour parallel to the dkection of elongation, and a high degree of localisation perpendicular to this direction.
142

Experimental Study of Acid Fracture Conductivity of Austin Chalk Formation

Nino Penaloza, Andrea 03 October 2013 (has links)
Acid fracture conductivity and the effect of key variables in the etching process during acid fracturing can be assessed at the laboratory scale. This is accomplished by using an experimental apparatus that simulates acid injection fluxes comparable to those in actual acid fracture treatments. After acid etching, fracture conductivity is measured at different closure stresses. This research work presents a systematic study to investigate the effect of temperature, rock-acid contact time and initial condition of the fracture surfaces on acid fracture conductivity in the Austin Chalk formation. While temperature and rock-acid contact are variables normally studied in fracture conductivity tests, the effect of the initial condition of the fracture surface has not been extensively investigated. The experimental results showed that there is no significant difference in acid fracture conductivity at high closure stress using smooth or rough fracture surfaces. In addition, we analyzed the mechanisms of acid etching and resulting conductivity creation in the two types of fracture surfaces studied by using surface profiles. For smooth surfaces, the mechanism of conductivity creation seems connected to uneven etching of the rock and roughness generation. For rough surfaces, acid conductivity is related to smoothing and deepening of the initial features on the sample surface than by creating more roughness. Finally, we compared the experimental results with Nirode-Kruk correlation for acid fracture conductivity.
143

The ionic conductivity of p(2-hydroxyethyl methacrylate) hydrogels / Darren A. Miller.

Miller, Darren A. January 1995 (has links)
Errata pasted on front end cover. / Bibliography: leaves 194-210. / xi, 210 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / The aim of this study is to investigate the conductivity of pHEMA gel electrolytes and improve the understanding of the absorbed water in such hydrogels. The effect of the variation of the water content on conductivity is investigated in two ways ; the introduction of OED cross linkers yields hydrogels of reduced EWC through alteration of the nature of the polymer network and progressive dehydration enables a study of the conductivity with decreasing water content for individual copolymers. / Thesis (Ph.D.)--University of Adelaide, Dept. of Physical and Inorganic Chemistry, 1996
144

Preparation and characterization of metal soap nanofilms/

Öztürk, Serdar. Balköse, Devrim January 2005 (has links) (PDF)
Thesis (Master)--İzmir Institute of Technology, İzmir, 2005. / Keywords: Electrical conductivity, langmuir blodgett technique, metal soaps, nanofilms, moisture adsorption. Includes bibliographical references (leaves. 127-132).
145

Thermal and electrical conductivities of the alkali metals

Hornbeck, John Wesley, January 1913 (has links)
Thesis (Ph. D.)--University of Illinois, 1913. / Biographical. "Reprinted from the Physical review, n.s., vol. II., no. 3, September, 1913."
146

The electrical conductivity of binary mixtures of iron blast furnace slag minerals

Lorig, Clarence Herman, January 1928 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1928. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 76-80).
147

Thermal conductivity of metal oxide nanofluids

Beck, Michael Peter. January 2008 (has links)
Thesis (Ph.D)--Chemical Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Teja, Amyn S.; Committee Member: Abdel-Khalik, Said I.; Committee Member: Meredith, Carson; Committee Member: Nair, Sankar; Committee Member: Skandan, Ganesh. Part of the SMARTech Electronic Thesis and Dissertation Collection.
148

Electron drift, diffusion, and ionization measurements in hydrogen with crossed electric and strong magnetic fields

Bernstein, Melvin J. January 1961 (has links)
Thesis (Ph.D.)--University of California, Berkeley, 1961. / "UC-34 Physics" -t.p. "TID-4500 (16th Ed.)" -t.p. Includes bibliographical references (p. 67-68).
149

Une conception nouvelle de la supraconductibilité ...

London, Fritz, Bauer, Edmond, Winter, J., January 1937 (has links)
Thèse--Université de Paris. / At head of title: ... F. London. Published also as no. 458 in series Actualités scientifiques et industrielles. Translated by Edmond Bauer and J. Winter. "Rèfèrences": p. [79]-80. Includes bibliographical references.
150

A study of bond-length fluctuations in transition metal oxides /

Yan, Jiaqiang, Goodenough, John B. January 2004 (has links) (PDF)
Thesis (Ph. D.)--University of Texas at Austin, 2004. / Supervisor: John B. Goodenough. Vita. Includes bibliographical references.

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