Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.

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The research of this work describes the degradation and conservation of archaeological hair fibers. Chapter I will be a brief overview, with Chapter II following with a literary review and definition of terms. Chapter III focuses on research centered on the structure of hair fibers and their physical and chemical attributes. It will also focus on the archaeological and historical evidence of hair fiber use by humans. This research will help form the backbone of the paper and experiments performed. The next chapter focuses on the degradation of hair fibers in different environments. Hair fibers left in underwater, open air, burial, and arid environments are monitored for degree of degradation and brittleness. The hair fiber types used are four commonly found hair fibers types: coarse wool, fine wool, mohair, and human hair. After deposition, conservation using silicone oil treatment is tested on the degraded hair fibers. When silicone oil treatment proves to be a viable conservation method, the technique is then be applied to two artifacts. The two artifacts used are a Victorian era watch fob made from human hair and hair fibers mixed with tar from the excavation of Kittern in Bulgaria. Chapter VII deals with the conclusions of the experiments as a whole. The degradation of the fibers in different environmental conditions show that burial in acidic sandy clay is the most detrimental to hair fibers, while hair fibers from arid, dry environments are brittle, but well preserved aesthetically. The silicone oil treatments are shown to be viable treatment methods with positive results for all of the fibers tested, including two artifacts, a Victorian watch fob made from human hair fibers and hair fibers mixed with a tar-like substance from the shipwreck Kittern in Bulgaria.

As the photonic crystal fibers (PCFs) are fabricated, it is hard to modulate their optical characteristics to function as tunable optical devices. To introduce tunable optical characteristics into the PCF structures, one can infiltrate liquids into the air holes of the PCFs to form the liquid-filled PCFs. However, the propagation losses become larger due to the finite liquid-hole layers and the lossy liquids infused in all the air holes of the cladding. In this thesis, an efficient full-vector finite-difference frequency-domain (FDFD) mode solver cooperated with the PMLs is utilized to investigate the propagation characteristics of the selectively liquid-filled PCFs. The propagation constants and the propagation losses of the guided modes on the selectively liquid-filled PCFs can be successfully obtained. From our numerical results, the propagation losses of both the internally liquid-filled PCFs and externally liquid-filled PCFs can be efficiently reduced by the outer or inner air-hole layers, and the useful tunablility characteristics for optical device applications can be maintained. Besides, the dispersion-related devices based on the selectively liquid-filled PCFs are also investigated. It is demonstrated that a DFPCF with the flatten dispersion value D within 0 ¡Ó 1 ps/nm/km over £f = 1.45 £gm to 1.65 £gm or a DCPCF with a high negative dispersion value D = -3100 ps/nm/km at £f = 1.55 £gm can be achieved by infiltrating the liquid into all air holes or specified air-hole layers. In the experiment, a simple selectively blocking technique using the microscopy, the tool fiber and the alignment technique is employed to fabricate the internally and externally liquid-filled PCFs. The measurement of the optical characteristics of these selectively liquid-filled PCFs is carried out and compared with the simulation results.

Thesis (Ph. D.)--Lehigh University, 2000. / Includes bibliographical references and vita.

Thesis (Ph. D.)--Lehigh University, 2000. / Includes vita. Includes bibliographical references (leaves 210-212).

Thesis (M.S.)--West Virginia University, 1999. / Title from document title page. Document formatted into pages; contains xviii, 177 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 140-141).