Thesis (M.S.)--West Virginia University, 2001. / Title from document title page. Document formatted into pages; contains xxxiv, 312 p. : ill. (some col.), col. map. Includes abstract. Includes bibliographical references (p. 305-312).

Thesis (M.S.)--West Virginia University, 2003. / Title from document title page. Document formatted into pages; contains xvi, 167 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 144-148).

Thesis (M.S.) in Civil Engineering--University of Maine, 2002. / Includes vita. Includes bibliographical references (leaves 65-68).

Nonwovens represent one of the booming sectors in the textile industry today with a significant projected growth both domestically and globally. At present, cotton is supplanted by synthetic fibers in nonwovens, thereby limiting its utilization in an important market sector. One of the major challenges for cotton is the high variability and lack of uniformity associated with fiber properties. Currently, manufacturers do not take this variability into account while selecting cotton for nonwovens. Therefore, it is essential to understand the effect of fiber properties on the nonwoven fabric characteristics in order to address this problem of variability. Bridging this knowledge gap can help increase cotton’s market share in the nonwoven sector and maintain its competitiveness in the fiber market. This project was an exploratory study to investigate the effect of cotton fiber properties on nonwoven fabric properties. Twenty different samples of Upland cotton with various combinations of fiber length and maturity parameters were used for this research. The fabric mechanical properties – tensile and burst strength, pore structure characteristics and permeability were measured and investigated in this study. The relationships between various raw fiber properties and the measured fabric characteristics were analyzed. The breaking strength of the fabric showed significant relations with fiber length and maturity. Using multiple regression analysis, an equation was derived to predict the specific breaking strength of the fabric from the mean fiber length and maturity ratio values of its constituent fibers. Though bursting strength and permeability showed significant single relations with several fiber properties, the multiple regression analysis returned a single significant predictor in each case – fiber length and fabric density respectively. Results observed from this study show that the constituent fiber attributes have significant relationships with the nonwoven fabric characteristics. Taking these fiber properties into account during raw material selection for cotton nonwovens would be advantageous as manufacturers can optimize quality, and also predict final product characteristics. Future studies focusing on the inter-fiber interactions in cotton nonwovens, comparisons between 100% cotton and synthetic blended nonwovens etc. will help gain better understanding, and contribute towards improving cottons marketability and utilization in the nonwoven industry. / text

published_or_final_version / abstract / toc / Mechanical Engineering / Master / Master of Philosophy

An interferometric method for measuring the total dispersion of short lengths of optical single mode fiber has been demonstrated. An analysis of the system in terms of linear system theory has also been carried out. The experiments were performed using a multimode GaAlAs semiconductor laser to measure the total dispersion of a borosilicate single mode optical fiber at a wavelength of approximately .873 μm. The experiments were conducted using various combinations of laser spectral width and fiber length. Changing the drive current to the laser enabled its spectral width to be varied from 2.3 nm to 5.8 nm FWHM. The fiber length was varied from approximately 0.2 m to 1.0 m. An analysis was also carried out to explain the effects on the interferograms of the unequal mode spacing of the multimode GaAlAs laser. Two methods of approximating the amount of variation of the laser mode spacing were also developed based on analysis of the interferograms. Analysis of the auto-correlation interferogram allowed the GaAlAs laser spectral width to be determined. This data was then used to compute a cross-correlation interferogram and then compared with the measured cross-correlation interferogram. The value of the fiber dispersion used in calculating the cross-correlation interferogram was varied until the computed interferogram agreed with the measured interferogram, this determined the value of the dispersion for the fiber that was used in that experiment. The experimentally determined value of the total dispersion of the single mode optical fiber used in these experiments agreed very well with published results.

No description available.

The work embodied in this dissertation is specifically focused on the evanescent interaction of light with thin-films which has lead to two related instrument based projects: i) the Electroactive Fiber-Optic Chip (EA-FOC) and ii) Attenuated Total Reflectance (ATR) spectroscopy of novel materials. The EA-FOC combines the sensitivity of an electroactive total internal reflection element (20 to 50 times more sensitive than a transmission experiment) with the ease of use of fiber-optic based CCD spectrometers. A side-polished optical fiber, in a V-groove glass mount, forms the planar platform, which allows access to the evanescent field escaping from the fiber core. The exposed evanescent field, which was used to probe molecules or molecular assemblies supported by the platform, has an interaction area ca. 0.05 cm squared. Thin-film and bulk absorbing samples, and waveguide modeling calculations were initially used to evaluate the sensitivity of the FOC platform, which was found to be analogous to ATR instrumentation. The wavelength range of the FOC platform was increased to include the near-UV and applied to monitor adsorption of a protein film. Fluorescence applications of the FOC were demonstrated using a fluorescence bioassay and a drop cast nanoparticle film. Finally, a transparent conducting oxide film, ITO, was added to the surface of the platform to complete the EA-FOC for spectroelectrochemical applications. A methylene blue redox couple and an electrodeposited ultra-thin PEDOT film were used to probe the capabilities of the EA-FOC. The EA-FOC was shown to be a multifunctional platform for advanced sensor technologies requiring absorbance, fluorescence, and electrochemical detection or a combination thereof.ATR spectroscopy of novel materials included the evaluation of two architectures: i) a pH sensitive polyelectrolyte film and ii) surface capture of a nanoparticle film. Absorbance spectra of a polyaniline/polyacetic acid self-assembled bilayer were evaluated with respect to pH and potential using ATR spectroscopy; the ultimate application of the polymer signal transduction layer was to monitor proton transport across a lipid-bilayer. Additionally, ATR spectroscopy was used to monitor adsorption of pyridine capped nanoparticles on a silyl-propyl-thiol modified surface.

No description available.

No description available.