Call number: LD2668 .T4 1986 C443 / Master of Science / Chemistry

Digitized by Kansas Correctional Industries

This investigation applied the techniques of polarography and controlled potential electrolytic reduction to the study of a series of unsymmetrical benzils. Eleven unsymmetrical benzils were synthesized and studied in 50% ethanol-water (by volume) solvent systems buffered at pH 1, 5, and 13. The results showed that, with unsymmetrical benzils substituted with electron-withdrawing or electrondonating groups, the carbonyl closest to the ring with the least electron-donating power was the preferred reaction site. However, the dicarbonyl system was nevertheless reduced as a unit, and Hammett sigma values of disubstituted symmetrical benzils were approximately additive. This was ascertained by comparing the ease of reduction of eight unsymmetrical benzils to the ease of reduction of the corresponding disubstituted symmetrical benzils. It was proposed that the electrons were added to the oxygen of one carbonyl, and that the second carbonyl was involved in the reduction chiefly through complete polarization of the dicarbonyl system at the electrode. In general, the reduction of unsymmetrical benzils appeared to follow the same path previously reported for symmetrical benzils.

Thesis (M.S.)--University of Missouri, School of Mines and Metallurgy, 1924. / The entire thesis text is included in file. Typescript. Title from title screen of thesis/dissertation PDF file (viewed June 23, 2009) Includes bibliographical references (p. 105).

Thesis (PH. D.)--University of Nebraska. / Bibliography: p. 3-4. Also issued in print.

Thesis (Ph. D.)--Columbia University, 1934. / Vita.

Thesis (PH. D.)--University of Nebraska. / eContent provider-neutral record in process. Description based on print version record. Bibliography: p. 3-4.

No description available.

The object of this thesis is to discuss an experimental composite conservation process and its significance for the future of artifact conservation. Composite artifacts are artifacts comprised of multiple materials such as wood, iron, and brass. The experiment was designed around five Civil War Enfield rifles from the wreck of the Civil War blockade runner Modern Greece. The main conservation difficulty for both metal and wood from a saltwater site is the presence of chlorides. If not removed, the chlorides will cause the metals to further corrode. If the chlorides are left within the wood, once the wood dries the chlorides will crystallize and burst remaining cellular structure. The second major problem for wood is the cellular structure itself. Degraded waterlogged wood loses most of its cellular structure while submerged and this must be reinforced prior to drying or partial to total collapse of the wood will occur. Composite artifacts pose one more serious problem, their composite nature. In most instances treatments for one material type are damaging to the other materials present. Disassembly of an artifact often has detrimental effects on the whole artifact whether through initial damage or the inability to reassemble the artifact after stabilization. In 1979, four Enfield rifles from Modern Greece were compositely conserved using either tetraethyl orthosilicate, sucrose, or isopropyl rosin. All three treatments focused on the conservation of the wood, resulting in the current poor condition of the iron elements. The research of this thesis uses the combined treatments of silicone oil (to treat the wood) and electrolytic reduction [ER] (to stabilize the metals), with minimal disassembly. It was discovered that prolonged exposure of the wood elements during ER had deleterious effects, post the silicone oil treatment. This prompted a re-evaluation of the research strategy. It was determined to do a re-treatment of the wood components of four of the rifles with silicone oil after the ER process. It was apparent during the ER process that iron components had loosened and could be removed allowing the wood to be extracted from the ER process earlier than the iron. Even though the experiment did not go as planned and the initial results were undesirable, valuable information was ascertained for treatment strategies and positive results are expected for the final four rifles. The retreatment of the wood with silicone oil should allow the wood to retain its shape, making reassembly possible.

The object of this thesis is to discuss an experimental composite conservation process and its significance for the future of artifact conservation. Composite artifacts are artifacts comprised of multiple materials such as wood, iron, and brass. The experiment was designed around five Civil War Enfield rifles from the wreck of the Civil War blockade runner Modern Greece. The main conservation difficulty for both metal and wood from a saltwater site is the presence of chlorides. If not removed, the chlorides will cause the metals to further corrode. If the chlorides are left within the wood, once the wood dries the chlorides will crystallize and burst remaining cellular structure. The second major problem for wood is the cellular structure itself. Degraded waterlogged wood loses most of its cellular structure while submerged and this must be reinforced prior to drying or partial to total collapse of the wood will occur. Composite artifacts pose one more serious problem, their composite nature. In most instances treatments for one material type are damaging to the other materials present. Disassembly of an artifact often has detrimental effects on the whole artifact whether through initial damage or the inability to reassemble the artifact after stabilization. In 1979, four Enfield rifles from Modern Greece were compositely conserved using either tetraethyl orthosilicate, sucrose, or isopropyl rosin. All three treatments focused on the conservation of the wood, resulting in the current poor condition of the iron elements. The research of this thesis uses the combined treatments of silicone oil (to treat the wood) and electrolytic reduction [ER] (to stabilize the metals), with minimal disassembly. It was discovered that prolonged exposure of the wood elements during ER had deleterious effects, post the silicone oil treatment. This prompted a re-evaluation of the research strategy. It was determined to do a re-treatment of the wood components of four of the rifles with silicone oil after the ER process. It was apparent during the ER process that iron components had loosened and could be removed allowing the wood to be extracted from the ER process earlier than the iron. Even though the experiment did not go as planned and the initial results were undesirable, valuable information was ascertained for treatment strategies and positive results are expected for the final four rifles. The retreatment of the wood with silicone oil should allow the wood to retain its shape, making reassembly possible.