Polyacrylonitrile (PAN)/carbon nanotube (CNT) composite fibers were made using various processing methods such as conventional solution spinning, gel spinning, and bi-component gel spinning. The detailed characterization exhibited that the smaller and longer CNT will reinforce polymer matrix mostly in tensile strength and modulus, respectively. Gel spinning combined with CNT also showed the promising potential of PAN/CNT composite fiber as precursor fiber of the next generation carbon fiber. High resolution transmission electron microscopy showed the highly ordered PAN crystal layer on the CNT, which attributed to the enhanced physical properties. The subsequent carbonization study revealed that carbonized PAN/CNT fibers have at least 50% higher tensile strength and modulus as compared to those of carbonized PAN fibers. Electrical conductivity of CNT containing carbon fiber was also 50% higher than that of carbonized PAN fiber. In order to have carbon fiber with high tensile strength, the smaller diameter precursor fiber is preferable. Bi-component gel spinning produced 1-2 µm precursor fiber, resulting in ~1 µm carbon fiber. The tensile strength of the carbonized bi-component fiber (islands fibers) is as high as 6 GPa with tensile modulus of ~500 GPa. Further processing optimization may lead to the next generation carbon fiber.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

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Brassica napus L., which is commonly known as canola, is the largest sources of edible oil in Canada. The remaining plant material, such as the stem, remains unused for any immediate application and is returned to the soil for decomposition. An investigation has been conducted to extract, characterize and modify the fibre materials from B. napus stems for textile and apparel applications. In order to find the optimum retting conditions for retting time, four different retting parameters were evaluated including, retting temperature, material liquor ratio, water exchange and the reuse of retted water. It was discovered that the virgin-retted fibres from Brassica plants exhibit most of the required textile properties including dye absorbency, strength, and thermal behaviour. However, the virgin-retted fibres do not exhibit the required spinning (yarn transformation) properties (softness, flexibility and individual fibre entity). In order to modify the Brassica fibres for spinnability, three treatment methods were applied: 1) alkali, acid and softener treatment; 2) pectinase enzyme treatment; and 3) enhanced enzyme treatment. According to Method 5 of the American Association of Textile Chemists and Colorists (AATCC), Brassica fibers obtained from treatments 2 and 3 showed similar spinning properties, and demonstrated superior spinning properties to Brassica fibres obtained from treatment one. To determine the variability of the cultivars upon textile and spinning properties, seeds from twenty different Brassica cultivars consisting of three different species, B. napus, B. juncea L. and B. rapa L., were collected, planted, and harvested upon reaching physiological maturity. The virgin water-retted fibre samples were then treated with pectinase enzyme, and different spinning properties (stiffness, softness, individual fibre entity) and textile properties (fibre decomposition temperature, tenacity and dye absorbency) of enzyme-treated samples were evaluated. The current research suggests that producing fibers from canola stubble and stems could be an additional income source for canola growers. / October 2016

Faculty of Health Sciences Degree of Master of Science in Physiotherapy 9601486g / A study was conducted to determine the optimum position of the handlebar on the Johnny G. Spinning® bicycle to reduce low back pain in cyclists participating in a Spinning® class. A three period open label cross over design, involving thirty six subjects was conducted. Each subject participated in three Spinning® classes with a different handlebar height at each session. The saddle angle, saddle post height and fore/aft position of the saddle remained fixed to eliminate variability. The cyclists’ pain perception was measured via the Visual Analogue Scale, Lickert Scale and the McGill Pain Questionnaire. The results were analysed with respect to the change in the mean and standard deviation of the Visual Analogue Scale, the Lickert scale and the McGill Pain Questionnaire. The significance of the study was set at the 0.05 level. A zero value was recorded with respect to pain experienced by the cyclists during a Spinning® class on the VAS, Lickert scale and on the McGill Pain scale, when the handlebars were placed in the high handlebar height position on the Spinning® bicycle; this is the most important outcome of the study conducted. In conclusion, there is a statistically meaningful difference (p<0.001) between the mean values of pain recorded by participants of the low handlebar height compared to the normal handlebar height, with the normal handlebar height being the better position. The standard deviation remains relatively constant. No pain was recorded on the VAS, Lickert scale and on the McGill Pain scale when the handlebars were placed in the high handlebar height position on the Spinning® bicycle. The results of the study indicate that the high handlebar height position is the best position for participants in a Spinning® class.

The thesis presents the development of force controller to maintain desired normal forces during a very stiff contact operation conducted in a Computer Numerical Control (CNC) machine. Force controller approach described in this thesis requires the accurate knowledge of the nominal tool path a priori. Obtaining the nominal tool path accurately is carried out by a vision based profile tracking system presented in this thesis. Both the force control and visual profile tracking systems require the development of an active control system to respond to force and vision signals. To facilitate the active control, a two-stage approach has been taken. The first stage is to bring the CNC machine under real-time control of an external computer. The second stage is the design of the active axis controller. This is achieved by adding sensor feedback loops to the external axis controller. The purpose of the active vision based profile tracking system is to automatically generate the tool path accurately. Emphasis is on combining low resolution vision with visual control of the precision CNC machine to attain the accuracy required for metal spinning. Combination of visual profile tracking and an edge detection method that gives sub-pixel accuracy were used to obtain the required tool path. A curvature detection algorithm was developed to identify segments of the tool path by assuming that the tool path consists of circular and straight line segments. The developed active force controller operates in a dynamic setup and is used to maintain tool forces at desired levels. The complete control system operates in a manner similar to reaction compensation and the force controller can be viewed as an integrating on-off controller with minimum integral wind-up effect. As a result, a direct dependency of the control efforts on error signals has been eliminated. In addition, the force controller brings in artificial damping that ensures the stability of the control system. To demonstrate the effect of the force controller, spun component qualities were assessed.

Yarn hairiness affects not only the quality of products, but also the productivity in spinning and weaving. Too much yarn hairiness is undesirable for many end uses as well as the spinning and post spinning processes. The main aims of this project are to examine the hairiness features of various yarns and to reduce yarn hairiness. The thesis covers five related areas – hairiness assessment, factors affecting yarn hairiness, the hairiness of newly developed yarns, yarn hairiness reduction, and effect of yarn hairiness on the energy consumption in ring spinning. The worsted cashmere, pure wool and wool/cashmere blend yarns were employed to investigate the effect of some fibre parameters on the yarn hairiness. A single exponential distribution of the hair-length was confirmed first, using the data from the Zweigle G565 Hairiness Meter. A linear relationship was observed between the blend ratio and the hairiness indexes. In particular, the effect of fibre crimp or curvature on yarn hairiness is examined. The theory of yarn hairiness composition was also developed further. The effect of draft ratio and spindle speed on the hairiness of worsted wool yarn was examined next with a factorial experiment design. Several new hairiness indexes, namely the relative hairiness indexes, have been used to explain the results obtained. In the investigation of the hairiness of newly developed yarns, the hairiness of the Compact Spun and Roller-Jet-Spun yarns was examined first. The composition of the yarn hairiness, the hair-length distribution, and the effect of test speed on yarn hairiness were then studied. An important finding is that for both yarns, the predominant hairiness feature is the looped hairs. A comparison of the hairiness of Solospun yarns and the equivalent ring spun wool yarns was undertaken. The hair-length distribution of the Solospun yarn was examined first. The Solospun yarns used had fewer hairs in most hair-length groups and lower variations in hairiness. In addition, the effect of twist level and spindle speed on the hairiness of Solospun and conventional ring spun yarns has also been discussed. A novel approach of reducing yarn hairiness – spinning with a ‘Diagonal’ yarn path was examined next. Both ‘Left Diagonal’ and ‘Right Diagonal’ yarn arrangements were studied. A new finding is that the ‘Right Diagonal’ yarn path leads to reduced hairiness for the Z-twist yarn, while yarn evenness and tenacity are not as sensitive to the modified yarn path. The mechanism of hairiness reduction with the ‘Diagonal’ yarn path has been discussed. The spinning performance of “Right Diagonal” yarn arrangement has also been evaluated. Finally, the effect of yarn hairiness on the energy consumption in ring spinning has been investigated theoretically and experimentally. A theoretical model has been developed, which represents the first attempt at theoretically investigating the influence of yarn hairiness on energy consumption during the winding stage of ring spinning. The experimental results have generally confirmed predictions of this model. Recommendations for further research in this area have also been made in the concluding chapter of this thesis.

Dissertation (Ph. D.)--University of Akron, Dept. of Polymer Engineering, 2006. / "May, 2006." Title from electronic dissertation title page (viewed 10/11/2006) Advisor, Erol Sancaktar; Committee members, James L. White, Kyonsuku Min, Darrell H. Reneker, Wieslaw Binienda; Department Chair, Sadhan C. Jana; Dean of the College, Frank N. Kelley; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.

Thesis (Ph. D.)--Chemistry and Biochemistry, Georgia Institute of Technology, 2004. / Collard, David, Committee Co-Chair ; Schiraldi, David, Committee Member ; Liotta, Charles, Committee Member ; Weck, Marcus, Committee Member ; Srinivasarao, Mohan, Committee Member ; Kumar, Satish, Committee Co-Chair. Vita. Includes bibliographical references.

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