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1
Lyytik�inen, Katja Johanna. "Control of complex structural geometry in optical fibre drawing." University of Sydney. School of Physics and the Optical Fibre Technology Centre, 2004. http://hdl.handle.net/2123/597.
Full textAbstract:
Drawing of standard telecommunication-type optical fibres has been optimised in terms of optical and physical properties. Specialty fibres, however, typically have more complex dopant profiles. Designs with high dopant concentrations and multidoping are common, making control of the fabrication process particularly important. In photonic crystal fibres (PCF) the inclusion of air-structures imposes a new challenge for the drawing process. The aim of this study is to gain profound insight into the behaviour of complex optical fibre structures during the final fabrication step, fibre drawing. Two types of optical fibre, namely conventional silica fibres and PCFs, were studied. Germanium and fluorine diffusion during drawing was studied experimentally and a numerical analysis was performed of the effects of drawing parameters on diffusion. An experimental study of geometry control of PCFs during drawing was conducted with emphasis given to the control of hole size. The effects of the various drawing parameters and their suitability for controlling the air-structure was studied. The effect of air-structures on heat transfer in PCFs was studied using computational fluid dynamics techniques. Both germanium and fluorine were found to diffuse at high temperature and low draw speed. A diffusion coefficent for germanium was determined and simulations showed that most diffusion occurred in the neck-down region. Draw temperature and preform feed rate had a comparable effect on diffusion. The hole size in PCFs was shown to depend on the draw temperature, preform feed rate and the preform internal pressure. Pressure was shown to be the most promising parameter for on-line control of the hole size. Heat transfer simulations showed that the air-structure had a significant effect on the temperature profile of the structure. It was also shown that the preform heating time was either increased or reduced compared to a solid structure and depended on the air-fraction.
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Lyytikäinen, Katja Johanna. "Control of complex structural geometry in optical fibre drawing." Thesis, The University of Sydney, 2004. http://hdl.handle.net/2123/597.
Full textAbstract:
Drawing of standard telecommunication-type optical fibres has been optimised in terms of optical and physical properties. Specialty fibres, however, typically have more complex dopant profiles. Designs with high dopant concentrations and multidoping are common, making control of the fabrication process particularly important. In photonic crystal fibres (PCF) the inclusion of air-structures imposes a new challenge for the drawing process. The aim of this study is to gain profound insight into the behaviour of complex optical fibre structures during the final fabrication step, fibre drawing. Two types of optical fibre, namely conventional silica fibres and PCFs, were studied. Germanium and fluorine diffusion during drawing was studied experimentally and a numerical analysis was performed of the effects of drawing parameters on diffusion. An experimental study of geometry control of PCFs during drawing was conducted with emphasis given to the control of hole size. The effects of the various drawing parameters and their suitability for controlling the air-structure was studied. The effect of air-structures on heat transfer in PCFs was studied using computational fluid dynamics techniques. Both germanium and fluorine were found to diffuse at high temperature and low draw speed. A diffusion coefficent for germanium was determined and simulations showed that most diffusion occurred in the neck-down region. Draw temperature and preform feed rate had a comparable effect on diffusion. The hole size in PCFs was shown to depend on the draw temperature, preform feed rate and the preform internal pressure. Pressure was shown to be the most promising parameter for on-line control of the hole size. Heat transfer simulations showed that the air-structure had a significant effect on the temperature profile of the structure. It was also shown that the preform heating time was either increased or reduced compared to a solid structure and depended on the air-fraction.
3
Callister, Richard D. C. "The in-situ manufacture of a metal-loaded, anisotropically conductive adhesive." Thesis, Brunel University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.286803.
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Lyyttkäinen, Katja Johanna. "Control of complex structural geometry in optical fibre drawing /." Connect to full text, 2004. http://setis.library.usyd.edu.au/adt/public_html/adt-NU/public/adt-NU20041011.120247.
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Lyytikäinen, Katja Johanna. "Control of complex structural geometry in optical fibre drawing." Connect to full text, 2004. http://hdl.handle.net/2123/597.
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Thesis (Ph. D.)--University of Sydney, 2004.Title from title screen (viewed 14 May 2008). Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the School of Physics, Faculty of Science. Includes bibliographical references. Also available in print form.
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Shi, Hong. "Condition monitoring in the optical fibre drawing process through the use of neural networks." Thesis, Southampton Solent University, 1996. http://ssudl.solent.ac.uk/2422/.
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It is well understood that optical fibre quality can be affected by the conditions present during fibre drawing. fibre tension , drawing speed, furnace temperature, the atmosphere within the ddrawing zone, viscosity of the glass, pre-form neck down shape and vibration in the drawn fibre are all factors which may affect the drawing process, and consequently the properties of the optical fibre. Most of these factors can be affected by the behaviour of the drawing furnace. Therefor monitoring furnace condition and predicting furnace decay are very important to the optical fibre manufacturing process. However, furnace conditions are very complicated and cannot be described by traditional mathematical models. In order to implement condition monitoring more effectively, the effects of process parameters and vibrations on the porperties and geometry of germanium-doped silica-core single-mode fibre, the subject of the current study were investigated by experiments and literature survey. These results can be used to determine the optimum processing conditions and select feature parameters for a condition monitoring system. Sources of vibration were analysed in order to provide information on which subsequent work to minimise vibrations on the drawn fibre could be based. The feature parameters which relate to furnace decay were extracted from the selected drawing parameters and are presented in this thesis. A new non-contact tension measurement system was devised. Different kinds of neural networks and their application in the furnace condition monitoring systems were investigated and the results are reported. A neural network software with fast training speed and a data exchange interface was developed to meet the needs of this furnace monitoring system. This thesis oresents a novel on-line condition monitoring system for drawing furnaces in the optical fibre drawing process. This system utilises the feature parameters extracted from drawing parameters and a neural network as the learning and decision making component. It can monitor the performance of the drawing process and give a pre-warning when furnace decay occurs or drawing parameters exceed the allowed working range. Hence, fibre properties can be enhanced, the production yield can be improved and machine utilities can be increased. This system has been used on a production optical fibre drawing tower at Pirelli Cables Limited and a high success rate for recognising furnace condition was achieved.
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Alkoles, Omar M. S. "Mechanical behaviour and fracture toughness of unfilled and short fibre filled polypropylene both drawn and undrawn. Experimental investigation the effect of fibre content and draw ratio on the mechanical properties of unfilled and short glass fibre filled polypropylene." Thesis, University of Bradford, 2011. http://hdl.handle.net/10454/5510.
Full textAbstract:
The goal of this research is to investigate the combined effects of glass fibre reinforcement and molecular orientation in polypropylene-short glass fibre composites. Specimens have been fabricated using the injection moulding process and drawn using a small die drawing rig. The effects of die drawing on the fibre composites are complex, with the drawing process orienting both the polymer molecules and the glass fibres. This may be accompanied by the creation of voids in the polymer matrix and their destruction in the compressive stress field thus restoring the interfacial contact area between fibre and matrix. Unfilled and short glass fibre filled polypropylene specimens, with fibre content 7% wt, 13%wt, 27%wt, and 55%wt, were injection moulded prior to the die drawing process. An experimental program of die drawing within an oven at elevated temperature was conducted for polypropylene filled to various levels and at different strain rates. The specimens drew to draw ratios in the range ¿=1.41 to ¿=5.6. Mechanical characterization of the test materials has been conducted by examining the tensile stress strain and fracture behaviour under uniaxial conditions. The influence of glass fibre content and drawing conditions (draw ratio) on the fracture toughness and crack propagation was investigated using the double edge notched fracture test. The notch lengths ranged from 1.5 to 2.5 mm for 10 mm wide specimens. The critical stress intensity factor increased as the fibre content increased up to a limiting filler level. The fracture toughness of both unfilled and fibre filled polypropylene were found to be highly dependent on draw ratio. The results were analysed to find out the optimal draw ratio and fibre content that yielded the maximum modulus, strength and fracture toughness. Data showed that, at a given draw ratio, modulus, strength and fracture toughness increased with increasing fibre content to a maximum and then decreased. The optimum material was obtained at a draw ratio of 2.5 and filler loading 13wt%.
8
Walker, Trevor John. "The use of primitives in the calculation of radiative view factors." Thesis, The University of Sydney, 2013. http://hdl.handle.net/2123/10275.
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Compilations of radiative view factors (often in closed analytical form) are readily available in the open literature for commonly encountered geometries. For more complex three-dimensional (3D) scenarios, however, the effort required to solve the requisite multi-dimensional integrations needed to estimate a required view factor can be daunting to say the least. In such cases, a combination of finite element methods (where the geometry in question is sub-divided into a large number of uniform, often triangular, elements) and Monte Carlo Ray Tracing (MC-RT) has been developed, although frequently the software implementation is suitable only for a limited set of geometrical scenarios. Driven initially by a need to calculate the radiative heat transfer occurring within an operational fibre-drawing furnace, this research set out to examine options whereby MC-RT could be used to cost-effectively calculate any generic 3D radiative view factor using current vectorisation technologies.
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Bam, T. J. "A computer-based justification for using the simple bend test as the basis for predicting the performance of steel hooked-end fibres in reinforced concrete." Diss., University of Pretoria, 2019. http://hdl.handle.net/2263/75657.
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The classical test to confirm the performance of a given fibre design for use in reinforced concrete is the pull-out test. While attempts have been made to simulate the performance of such pull-out tests, in practice it has been found that there is a significant disparity between prediction and real-life performance.
The high strength of steel reinforcing fibres is a consequence of the cold wire drawing process and subsequent fabrication. Residual stresses exist in cold drawn wire as a consequence of the elastic response to a non-uniform distribution of plastic strain. This also introduces a yield strength profile where yield strength varies radially through the wire. The question arises as to whether fibre design should use a starting material model that considers these properties.
This thesis examines whether the tensile test, simple bend test and pull-out test provide enough information to define a starting material model that may be used for further design and simulation of such fibres.
Since the details of the wire drawing process and material specification are proprietary and therefore unknown, a sensitivity study was conducted to determine which aspects of the wire drawing process have the greatest effect on the pull-out curve and the following were established as being significant:
• Plastic strain due to wire drawing was shown to be the most important factor.
• The bilinear curve was shown to be a suitable approximation for the stress-strain curve.
• Replacing the plastic strain profile with a single value of average equivalent plastic strain is practical.
The following were established as having negligible effect:
• The consequences of the hooked-end forming process.
• The residual stress profiles due to wire drawing provided that the above was also excluded.
• The hardening law
While inverse analysis demonstrated that all tests provide sufficient information to determine the required properties for this bilinear material model, the pull-out test was shown to provide more accurate approximations of the maximum pull-out force at the first and second peaks and the bend test was shown to produce more accurate approximations of the energy associated with pull-out. Good correlation with the baseline pull-out curve was found for both the isotropic and the kinematic hardening laws and it is concluded that behaviour during pull-out is insensitive to the hardening law.
Sensitivity analysis and characterisation of the material model using an experimental pull-out curve demonstrated the importance of the coefficient of friction. Full characterisation using the pull-out curve therefore requires the solution to a three-variable problem: yield strength, tangent modulus and coefficient of friction. This was a suggested topic for further study.Dissertation (MEng)--University of Pretoria, 2019.
Mechanical and Aeronautical Engineering
MEng (Mech)
Unrestricted
10
Alkoles, Omar M. "Mechanical behaviour and fracture toughness of unfilled and short fibre filled polypropylene both drawn and undrawn : experimental investigation of the effect of fibre content and draw ratio on the mechanical properties of unfilled and short glass fibre filled polypropylene." Thesis, University of Bradford, 2011. http://hdl.handle.net/10454/5510.
Full textAbstract:
The goal of this research is to investigate the combined effects of glass fibre reinforcement and molecular orientation in polypropylene-short glass fibre composites. Specimens have been fabricated using the injection moulding process and drawn using a small die drawing rig. The effects of die drawing on the fibre composites are complex, with the drawing process orienting both the polymer molecules and the glass fibres. This may be accompanied by the creation of voids in the polymer matrix and their destruction in the compressive stress field thus restoring the interfacial contact area between fibre and matrix. Unfilled and short glass fibre filled polypropylene specimens, with fibre content 7% wt, 13%wt, 27%wt, and 55%wt, were injection moulded prior to the die drawing process. An experimental program of die drawing within an oven at elevated temperature was conducted for polypropylene filled to various levels and at different strain rates. The specimens drew to draw ratios in the range γ=1.41 to γ=5.6. Mechanical characterization of the test materials has been conducted by examining the tensile stress strain and fracture behaviour under uniaxial conditions. The influence of glass fibre content and drawing conditions (draw ratio) on the fracture toughness and crack propagation was investigated using the double edge notched fracture test. The notch lengths ranged from 1.5 to 2.5 mm for 10 mm wide specimens. The critical stress intensity factor increased as the fibre content increased up to a limiting filler level. The fracture toughness of both unfilled and fibre filled polypropylene were found to be highly dependent on draw ratio. The results were analysed to find out the optimal draw ratio and fibre content that yielded the maximum modulus, strength and fracture toughness. Data showed that, at a given draw ratio, modulus, strength and fracture toughness increased with increasing fibre content to a maximum and then decreased. The optimum material was obtained at a draw ratio of 2.5 and filler loading 13wt%.
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Chiloyan, Vazrik. "Polyethylene fiber drawing optimization." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/68829.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2011."June 2011." Cataloged from PDF version of thesis.
Includes bibliographical references (p. 33).
Polymer fiber drawing creates fibers with enhanced thermal conductivity and strength compared to bulk polymer because drawing aligns the molecular chains. I optimize the polymer fiber drawing method in order to achieve polymer fibers that are drawn to lengths exceeding 1cm and develop a method to cut and store them for future experimental purposes. With lengths exceeding 1cm, starting with lengths near 0.5mm, these fibers undergo very large tensile deformations. This ensures the fibers obtained have been ultra drawn, and the polymer chains have aligned, thus enhancing the tensile strength and thermal conductivity of the fiber. By storing these fibers, I can perform experimental measurements in the future to obtain thermal conductivity values for polyethylene fibers and notice the effect of aligning the molecular chains.
by Vazrik Chiloyan.
S.B.
12
GALLICHI, NOTTIANI DUCCIO. "Advanced phosphate glasses for photonics: from materials to applications." Doctoral thesis, Politecnico di Torino, 2021. http://hdl.handle.net/11583/2903486.
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Hou, Chong Ph D. Massachusetts Institute of Technology. "Fiber drawing : beyond the scaling paradigm." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/104183.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2016.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 93-97).
The emergence of multimaterial fibers that combine a multiplicity of solid materials with disparate electrical, optical, and mechanical properties into a single fiber presents new opportunities for extending fiber applications. Different functional fiber devices have been fabricated with a thermal co-draw approach. In order to make the thermal co-draw feasible, only materials with similar viscosity at the draw temperature are used, which excludes a wide range of metal and semiconductors that have good electrical property but not compatible viscosity profile. From the fiber structure point of view, the nature of the fiber drawing process makes fabricating a large quantity of fiber with identical inner structures feasible. The scalability of thermal drawing approach offers access to large quantities of devices however constrains the devices to be translational symmetric. Lifting this symmetry to create discrete devices in fibers will increase the utility of fiber devices. Also, the surface of the fiber is rarely studied though complex inner structure have been fabricated for different functionalities. Functionalize the fiber surface would give fiber the ability to better interact with the outer environment. This thesis seeks to address the abovementioned considerations, i.e. to expand materials selection for the fiber co-draw process and to explore variance of the fiber structure including breaking the inner structure translational symmetry and functionalize the outer surface. On the material side, a chemical reaction phenomenon is observed and studied in two different fiber drawing situations. In both cases, new composition is formed during the draw and play an important role in the formed fiber devices. On the structure side, relying on the principle of Plateau-Rayleigh instability, the fiber inner structure is designed to form a series of discrete semiconductor spheres contacting two metal buses after a thermal selective breakup process. This gives rise to photodecting devices in a silica-cladding fiber which shows a large working bandwidth. The fiber surface is also studied and successfully patterned with micron-scale features during the draw process. The formed patterned fiber surface shows potential in structural coloration and directional wetting.
by Chong Hou.
Ph. D.
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Hauptmann, Marek. "Neue Einsatzpotentiale naturfaserbasierter Materialien in der Konsumgüterproduktion durch die technologische Entwicklung des Ziehverfahrens am Beispiel der Verpackung." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-226715.
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Die Produktion verschiedener Arten von Gütern ist im globalen Kontext gesellschaftlicher Entwicklung fortwährend an die Verfügbarkeit von Ressourcen gebunden und durch diese zunehmend begrenzt. In den bis heute entstandenen Wertschöpfungsketten basiert die verlustarme und effiziente Verteilung von Produkten, Zwischenprodukten, Halbzeugen sowie auch Rohstoffen auf den spezifisch auf die jeweiligen Erfordernisse eingestellten Funktionen ihrer Verpackungen. Als Bindeglied in nahezu allen Teilen der Produktion werden die Verpackung und ihre Herstellung innerhalb des mit Abstand größten Teils ihrer Anwendung, den Konsumgüterverpackungen als Beispiel für die Diskussion von Einsatzpotentialen naturfaserbasierter Materialien verwendet. Die Habilitationsschrift stellt die Ausgangssituation in der weltweiten Konsumgüterproduktion und Ressourcenverfügbarkeit dar und ordnet die Position naturfaserbasierter Packmittel in diese ein. Es werden Technologien zur Formgebung naturfaserbasierter Materialien zu Packmitteln zusammenfassend dargestellt. Die Ziehtechnik wird im Speziellen in Form eines Leitfadens in ihren Wirkmechanismen und Prozessvarianten sowie in Bezug auf ihre technische Umsetzung dargestellt. Es werden Beispiele konkreter Anwendungsmöglichkeiten diskutiert.
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Yadav, Seemant. "Modeling of material response during fiber drawing of semicrystalline pet." Texas A&M University, 2003. http://hdl.handle.net/1969.1/5763.
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Accurate constitutive modeling of polymeric fibers presents a difficult and distinct
challenge. While significant progress has been made in constructing models
applicable for small strains and limited strain-rate and temperature regimes, much
less has been made for more general conditions. This is due in part to the
complexity of polymeric behavior. In this work, experimental results of uniaxial
extension tests on Polyethylene terephthalate (PET) were obtained from Dr.
S.Bechtel, were analyzed, and were formulated into a new model which explains
the behavior of PET at different temperatures and strains. The biggest impediment
in the determining the behavior of polymeric was the difference in the behavior of
PET above and below its glass transition temperature. Consequently, well
established (from microstructural considerations) constitutive models and concepts
for rubber elasticity and plasticity were not directly transferable to modeling PET
fibers. In the model, the PET fibers were assumed to be constituted by amorphous
and crystallization segments and the response of the material during stretching was
the combined response of simultaneous stretching of the amorphous and the crystalline segments. The strengthening mechanism is due to orientation of the
amorphous segments during stretching. The model involves a friction element
which took account of the plastic behavior below the glass transition temperature.
The model was used to predict the response of PET at different temperatures and
the results from the model showed good agreement with the experimental data. The
results from the research will be further used to increase the overall efficiency of
the fiber drawing process.
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Tchikanda, Serge William. "Modeling for high-speed high-strength precision optical fiber drawing." Diss., Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/20051.
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Marcille, David Francis. "Thermal model for drawing optical fibers in the post-melt region." Thesis, Georgia Institute of Technology, 1985. http://hdl.handle.net/1853/15922.
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Reeve, Hayden Matane. "Effect of natural convection heat transfer during polymer optical fiber drawing /." Thesis, Connect to this title online; UW restricted, 2003. http://hdl.handle.net/1773/7032.
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Litchfield, David W. "The Manufacture and Mechanical Properties of Poly(ethylene terephthalate) Fibers Filled with Organically-Modified Montmorillonite." Diss., Virginia Tech, 2008. http://hdl.handle.net/10919/27175.
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This work is concerned with mechanical property improvements to poly(ethylene terephthalate), PET, fibers by the addition of layered silicate nanoparticles and by drawing the un-oriented nanocomposite filaments in a second step. No previous studies on PET fibers filled with montmorillonite (MMT) nanoclay examined fiber drawability at temperatures above the glass transition. Therefore, the primary objective of this research was to determine 1) if PET nanocomposite fibers could be drawn to finer diameters and 2) whether drawing imparted improved Young's modulus and tenacity (i.e. strength) relative to un-filled PET fibers. Of equal importance to this work, the subsequent objective was to discern and understand the role of nanoclay in 1) the production of improved or reduced mechanical properties and 2) the ability to draw PET to lower or higher than normal draw ratios.
In the first part of this thesis, the improvements in Young's modulus and tenacity of PET fibers filled with various types of organically modified montmorillonite is shown and the method to produce them is discussed. Greater improvements in mechanical properties occurred when the MMT stacks were intercalated with PET. A nominal 1 wt% loading of dimethyl-dehydrogenated tallow quaternary ammonium surface modified MMT in drawn PET fiber showed a 28% and 63% increase in Young's modulus and strength, respectively. Relative to an un-filled PET fiber, these results exceeded the upper-bound of the rule of mixtures estimate. Therefore, both the type of surface modification and concentration of MMT were shown to affect the degree of PET orientation and crystallinity. Furthermore, drawability above Tg and elongation-at-break increased upon the addition of organically modified MMT to un-oriented PET fibers, which was a key distinction of this work from others examining similar systems.
Interestingly, the mechanical properties of modulus and tenacity showed a maximum with concentration of alkyl modified clay, but drawability did not show significant variation with increasing nanoclay content. Thermal analysis and Raman spectroscopy was used to examine the role of nanoclay in creating this maximum in mechanical properties. At low loadings, nanoclay was shown to intercalate with PET and enhance amorphous orientation. At higher concentrations of nanoclay the presence of large agglomerates prevented efficient orientation to the fiber axis and acted as stress concentrators to aid in cavitation and failure during testing. Raman spectroscopy showed that the as-spun unfilled PET fibers possessed significantly more trans conformer content of the ethylene glycol moiety than the nanocomposite fibers. The greater gauche content of the nanocomposite fibers delayed crystalline development during non-isothermal DSC scans to higher temperatures was associated with the increased drawability.Ph. D.
20
Wei, Zhiyong. "Thermo-fluid modeling and robust control of modern optic fiber drawing processes." Diss., Available online, Georgia Institute of Technology, 2004, 2004. http://etd.gatech.edu/theses/available/etd-04092004-135913/unrestricted/wei%5Fzhiyong%5F200405%5Fphd.pdf.
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Thesis (Ph. D.)--Mechanical Engineering, Georgia Institute of Technology, 2004.Kok-Meng Lee, Committee Chair ; Andrei G. Fedorov, Committee Member ; William E. Singhose, Committee Member ; David G. Taylor, Committee Member ; Zhi Zhou, Committee Member. Includes bibliographical references.
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Parise, Ronald J. "A heat transfer and fluid flow model for the drawing of optical fibers." Diss., Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/18221.
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Floyd, Adam R. "Synthesis and Characterization of Si, Ge, and SixGe1-x Nanowires by Fiber Drawing." Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/91179.
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This research provides a method of using a mixed powder in tube approach for producing and characterizing large quantities of highly oriented, high aspect ratio semiconductor nanowires in an inherently safe and contained manner. This work modifies the previously used mixed powder method to produce significantly smaller features below 100nm in diameter. For the first time SiGe alloys are produced in optical fiber from a mixture of the two powders across the entire compositional range.
A discussion of the properties of silicon and germanium and their alloys is given with emphasis on the differences between properties at the bulk scale and at the nanoscale. The limitations of silicon and germanium for photonic applications, due to their indirect band gap nature, is removed when these materials are reduced to the nanoscale. A brief discussion of ways that these properties can be modified is given with size, composition, and strain all being viable factors of control.
The optical and electrical properties of these nanowire arrays is evaluated as a function of the size, number of wires, and composition. A clear dependence between size and quantity of wires was observed with respect to composition. The nanowires were found to have complex interactions with light showing high absorption as well as unique transmission characteristics. Arrays of these fibers were able to create a measurable photocurrent and provide potential uses for detection of light and other photonic applications.
An understanding of the etching necessary to both expose these nanowires for analysis as well as completely remove them from the glass matrix was developed. Etch rates in these areas was observed to be higher than reported etch values. Etching with dilute solutions was found to allow removal of the wires cleanly and allow recovery of them for other applications.Master of Science
This research provides a method of using a mixed powder in tube approach for producing and characterizing large quantities of highly oriented, high aspect ratio semiconductor nanowires in an inherently safe and contained manner. These wires are over 1000 times smaller than thickness of a human hair are made using traditional fiber drawing methods or pulling at high temperatures. These fibers differ from traditional optical fibers in that they are produced from a tube filled with powder instead of a solid glass rod. This is similar to the same method used to produce wires in other materials such as copper. The use of the glass to contain the semiconductor material allows us to increase the temperature it is pulled at above the melting point. The liquid material is then drawn into the very small sizes using pores in the glass powder it is mixed with. This allows these wires to be produced in much longer lengths, larger quantities, and easier than previous methods. These nanowires are produced from silicon and germanium, which are two of the most important materials currently used in electronics. These semiconductors are used in most electronics, solar cells, and LEDs that are used in everyday life. Silicon and germanium while very important materials have limitations in photonic applications, interactions with light. The properties of the materials for these applications can be improved by reducing them in size to the nanoscale. The wires produced in this research were evaluated to determine if they possessed the more ideal properties. The wires were found to have detectable photocurrent, electricity generated from light. This is the primary property that is needed in solar cells. The wires produced in this method are an important early step to improving solar cells efficiency and reliability. These v wires have benefits over other forms of silicon because they are produced with protective glass coating in a single step.
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Hsiao, Hsien-Fu. "Mechanical behavior and heat transfer in polymer fiber melt-spinning and drawing processes." Connect to resource, 1997. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osuosu1243349868.
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Vermillac, Manuel. "Nanoparticules dans les fibres optiques en silice dopées aux ions luminescents et leur évolution au cours de l’étirage." Thesis, Université Côte d'Azur (ComUE), 2017. http://www.theses.fr/2017AZUR4098/document.
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Le développement de nouvelles fibres optiques en silice repose sur l’insertion des ions luminescents (ions de terres rares) dans des nanoparticules diélectriques. Dans ce contexte, la taille des particules est un paramètre clef qu’il convient de contrôler afin de bénéficier des nouvelles propriétés. Pour répondre à cet impératif, l’objectif de cette thèse était double. Premièrement, dans un objectif de structuration, il a été important d’étudier l’évolution des caractéristiques du matériau au cours de la fabrication, et deuxièmement, l’évolution des propriétés de luminescence avec les caractéristiques du matériau. La première partie de ce manuscrit décrit les différents types d’évolution des nanoparticules qui ont été observées au cours de ce travail de thèse. La réaction chimique de nanoparticules avec la matrice en silice est abordée dans l’étude du dopage par des nanoparticules de LaF3. Une observation originale de l’allongement et de la fragmentation de particules durant l’étirage en fibre optique est présentée. L’évolution thermodynamique des particules au cours de l’étirage, ainsi que l’influence des paramètres de l’étirage sont abordées. Enfin, la seconde partie de ce manuscrit se focalise sur le lien entre le matériau et ses propriétés spectroscopiques (Tm3+, Er3+). Les résultats montrent notamment que l’ajout de lanthane dans les fibres optiques dopées aux ions thulium augmente les pertes optiques, mais permet aussi d’augmenter la durée de vie du niveau 3H4 du Tm3+ jusqu’à un record de 58 μs pour une fibre transparente (pertes inférieures à 0,1 dB.m−1). Ces résultats confirment ainsi la nécessité d’un compromis sur la taille des particules et l’importance de ces travaux sur leurs possibilités de structurationThe development of new silica-based optical fibers is relies on the insertion of luminescent ions (rare-earth ions) in dielectric nanoparticles. In this context, particle size is a key parameter that should be controlled in order to benefit from the new properties. To reach this goal, the objective of this thesis was twofold. Firstly, it was important to understand, to engineer its structuration, the evolution of the characteristics of the material during its fabrication process, and secondly, the evolution of the spectroscopic properties with the characteristics of the material. The first part of this manuscript describes the different types of evolution of the nanoparticles that were observed during this thesis work. The chemical reaction of nanoparticles with the silica matrix is discussed in the study of LaF3-nanoparticles doping. Also, an original observation of the elongation and the break-up of particles during the fiber drawing are presented. The thermodynamic evolution of the particles during the fabrication process as well as the influence of its parameters are discussed. Finally, the second part of this manuscript focuses on the link between the material and its spectroscopic properties (Tm3+, Er3+). In particular, the addition of lanthanum in the Tm3+-doped fibers increased the optical losses, but also enabled the increase of the lifetime of the 3H4 level up to a record in silica of 58 μs (optical losses below 0,1 dB.m−1). These results highlight the need for a compromise on particle size and the importance of this work on structuring possibilities
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Bradshaw, Anne. "State of Being." VCU Scholars Compass, 2006. http://scholarscompass.vcu.edu/etd/1233.
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My work speaks to the processes of adaptation and assimilation, phenomena that explain the way in which we transform life experience and incorporate the effects of such experience into the daily workings of our psyche. To this extent my work is a self-analysis, an autobiographical reckoning, a non-verbal representation of collective experiences rendered in forms upon which images are spontaneously drawn or painted with fiber. The process of making art as a means of accessing creative instincts is a manifestation of the way in which I experience life. Adapting and assimilating to our human condition is an art, a form of survival that allows for self-expression as a technique of understanding, a way of translating beauty into collective consciousness, a means of transforming atrocity too enormous for words, an offer of conversation that transcends human reason, a sharing of imagination that embraces the past, the present and the future. As the world grows increasingly complex, our very existence is threatened by terrorist attacks, natural disasters, and socioeconomic confusion. A culture driven by consumerism responds to global competition for technology that races against the speed of light. Human misunderstanding is relegated to war, courts of law and bi-partisan politics. Adapting and assimilating life circumstances and experiences with a sensitivity to the interplay of intensely colorful fiber in my hands affects an optimistic and energetic reinterpretation of life's complexity. In a time of uncertainty, art is a reason for hope.
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何中芳 and Chung-fong Jonathan Ho. "Poly(methylmethacrylate) dentures reinforced with highly drawn polyethylene fibres: dimensional changesduring processing and in service." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1998. http://hub.hku.hk/bib/B29968008.
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Cheng, Yi-yung, and 鄭而容. "Denture base resin reinforced with highly drawn linear polyethylene fibres: dimensional changes and dentureconstruction technique." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1994. http://hub.hku.hk/bib/B38627991.
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Cheng, Yi-yung. "Denture base resin reinforced with highly drawn linear polyethylene fibres dimensional changes and denture construction technique /." Click to view the E-thesis via HKUTO, 1994. http://sunzi.lib.hku.hk/HKUTO/record/B38627991.
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Ho, Chung-fong Jonathan. "Poly(methylmethacrylate) dentures reinforced with highly drawn polyethylene fibres : dimensional changes during processing and in service /." Hong Kong : University of Hong Kong, 1998. http://sunzi.lib.hku.hk/hkuto/record.jsp?B21129563.
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Gregg, Ashley. "Holler." Digital Commons @ East Tennessee State University, 2020. https://dc.etsu.edu/etd/3712.
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The artist discusses her Master of Fine Arts thesis exhibition Holler, held at Tipton Gallery March 2ndto March 13th, 2020. The exhibition features an installation of works on fiber, paper, and found objects tied to her upbringing in Southern Appalachia. A variety of collected materials including bedsheets, chalkboards, and barbwire are taken out of their traditional contexts and brought into a new vantage point through the artist’s alterations.
Gregg re-contextualizes materials, language, and signifiers as a process of decoding formative experiences in domestic and academic spaces. Themes examined in the work include rote learning, tradition, indoctrination, identity, and cultural psychology. Literary references include writings on critical pedagogy by educators Paulo Freire and Bell Hooks. The influence of conceptually driven artworks by Adrian Piper and Bruce Nauman and their relation to language and repetition are discussed, as well as the themes of identity and domesticity as seen in the works of Tracey Emin and Mona Hatoum.
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Schiffnederová, Markéta. "LABYRINT." Master's thesis, Vysoké učení technické v Brně. Fakulta výtvarných umění, 2017. http://www.nusl.cz/ntk/nusl-295736.
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In the past, my work was focused on transferring the flat visual element into the space. I turn away from this concept, because as my Master's thesis I chose a Labyrinth. A labyrinth is not primary flat visual element. My final work is free artistic interpretation of this theme. My work based on classical craftsmanship techniques, which I am using in the new way in my work. I understood this theme labyrinth as an something very personal and individual. Because of this, I decide to create sculpture which will fit in to the gallery space and also the space of everyday life. My expression of the Labyrinth has cube shape. The entire sculpture is stitched inside, this stitch create the inside space. In one way this inner space is open and we are free to look inside, in the other hand center of the sculpture is hidden. I want to express a feeling of secrecy, and create tension between outside and inside space of the sculpture.
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Heyl, Hanna Verena. "Phase Relations in the YBa2Cu3O7-x - SiO2 System and the Impact on Superconducting Fibers." Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/95058.
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This dissertation presents the first reported identification and analyses of the phase relations in the YBa2Cu3O7-x (YBCO)-SiO2 system at elevated temperatures. In this regard, a rigorous characterization study of the reaction phases within YBCO glass fibers, heat-treated YBCO+SiO2 pellets, rapid thermally annealed YBCO+SiO2 rods and rapid thermally annealed YBCO powder inside a fused silica tube is provided. These analyses are based on a vast set of generated novel results obtained using energy dispersive spectroscopy analyses on an environmental scanning electron microscope, X-Ray diffraction analyses, Raman spectroscopy, X-ray photoelectron spectroscopy analyses and a cross-polarized light study.
First, original drawings of YBCO into glass fibers using the molten-core approach on a fiber draw tower in air and oxygen atmospheres are presented and analyzed. The performed analyses reveal the occurrence of reactions between the YBCO core and the silica cladding in as-drawn fibers as well as after additional heat-treatments. A detailed analysis and characterization of the occurring dissolution and diffusion based reaction processes is, then, provided along with the identification of the arising phase separation. Moreover, in order to analyze drawing YBCO glass fibers at lower temperatures, the use of borosilicate as the preform material is also investigated.
This varied set of experiments and associated analyses reveal that the as-drawn YBCO fibers contain an amorphous core and that cuprite (Cu2O) is the first phase to crystallize out of the amorphous silicate matrix upon heat-treatment. Furthermore, the obtained results demonstrate the dissolution of the fused silica cladding into Si4+ and O2- ions and their subsequent diffusion into the molten YBCO core, leading to phase separation due to an occurring miscibility gap in the YBCO-SiO2 system as well as to silicate formation and amorphization of the YBCO core. This, as a result, prohibits the formation of the superconductive YBCO (Y-123) phase upon annealing. In addition, heat-treatment analyses show that higher temperatures or prolonged dwelling times at lower temperatures lead to the formation of barium copper and yttrium barium silicates. The analysis focusing on the use of borosilicate as the preform material reveals that drawing at lower temperatures reduces the dissolution and diffusion based reactions, but does not prevent them. Furthermore, the analysis on YBCO glass fibers with a fused silica cladding drawn in oxygen atmosphere shows that a higher oxygen content increases the dissolution of the fused silica cladding into its ions and their subsequent diffusion into the molten YBCO core.
In addition, the performed heat-treatments on YBCO+SiO2 pellets in air and oxygen atmospheres demonstrate the gradual decomposition of the Y-123 phase with an increase in SiO2 content. Moreover, the rapid thermal annealing experiments with a subsequent quenching step on YBCO+SiO2 rods and on YBCO powder inserted inside a fused silica tube show the decomposition of the Y-123 phase and the formation of phases similar to the phases obtained in the YBCO glass fiber study, thus corroborating the results thereof.
In summary, this dissertation enables the determination of the phase relations and reaction processes within the YBCO-SiO2 system, the identification of the direct effects of the silicon content on the Y-123 phase decomposition, as well as a rigorous characterization of the dissolution and diffusion based reactions within the YBCO-SiO2 glass-clad fiber system. The generated results and drawn conclusions build a fundamental understanding of phase relations in the YBCO-SiO2 system, which enables a definite assessment of the feasibility of manufacturing long-scale purely superconductive YBCO glass fibers using the molten-core approach and introduces advanced contributions to general glass-clad fiber systems manufactured using this method.Doctor of Philosophy
This dissertation provides the first reported identification and analysis of the phase relations in the YBa2Cu3O7-x (YBCO)-SiO2 system at high temperatures. In this regard, a thorough characterization study of the reaction phases within YBCO glass fibers drawn using the molten-core approach on a fiber draw tower is provided. In addition, heat-treatment analyses considering YBCO+SiO2 pellets, rapid thermally annealed YBCO+SiO2 rods and rapid thermally annealed YBCO powder inside a fused silica tube are performed to gain further fundamental insights. The performed analyses are based on a wide set of characterization methods including energy dispersive spectroscopy on an environmental scanning electron microscope, X-Ray diffraction analyses, Raman spectroscopy, X-ray photoelectron spectroscopy and a cross-polarized light study. Our experimental results and performed analyses identify the phase relations and reaction processes within the YBCO-SiO2 system at elevated temperatures, demonstrate the direct effects of the silicon content on the superconductive YBCO phase decomposition, enable drawing definite conclusions regarding the feasibility of manufacturing long-scale purely superconductive YBCO glass fibers using the molten-core approach, and, characterize the dissolution and diffusion based reactions occurring within the YBCO-SiO2 glass-clad fiber system. In a nutshell, this dissertation provides a fundamental understanding of phase relations in the YBCO-SiO2 glass-clad system as well as key insights covering general glass-clad fibers drawn using the molten-core approach, paving the way for improved glass-clad fiber manufacturing using this method.
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Jain, Vibhor. "Analysis of structural development during superdrawing of poly(ethylene terephthalate) fibers." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/28185.
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Thesis (M. S.)--Polymer, Textile and Fiber Engineering, Georgia Institute of Technology, 2009.Committee Chair: Wang, Youjiang; Committee Co-Chair: Jacob, K.I.; Committee Member: Aneja, A.P.; Committee Member: Garmestani, Hamid; Committee Member: Thio, Yonathan S.; Committee Member: Yao, Donggang
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Zápotočný, David. "Návrh betonové konstrukce s ohledem na požární odolnost." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2020. http://www.nusl.cz/ntk/nusl-409785.
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Diploma thesis deals with design of selected parts of reinforced concrete construction of a multi-storey building with respect of fire resistance. The proposed elements are reinforced concrete locally suported ceiling slab, selected column and wall. These structures are located in the storage hall on the 1st underground floor. Different variants of structural design are consulted and compared in this work. The calculation of internal forces is performed in the calculation software Scia Engineer 19.1. The thesis includes a structural design as well as drawings. The construction is designed according to ČSN EN standarts.
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Hu, Cheng-Bin, and 胡正彬. "Study of fiber-drawing process and Yb-doped fiber laser." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/46865555576196541476.
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碩士國立聯合大學
光電工程學系碩士班
98
In this thesis, we focus on three main works , firstly, we modified the fiber drawing tower and increased the fiber diameter monitoring devices and UV coating devices. During the drawing process , we wrote a LabVIEW program to read and control the diameter of fiber. We could well control the diameter of drawing fiber within the range of 125μm±5μm. Secondly, we arranged the 915nm laser diode 、modulated chopper 、lock-in amplifier and optical spectrum analyzer to set up a fluorescence spectrum measurement system. The results showed that the fluorescence spectrum of the Ytterbium-doped fiber was from 960nm to 1100nm, and four peaks were located at 970nm, 995nm, 1020nm and 1048nm. Finally, a 915nm semiconductor laser as the pumping source was coupled into the Triple-core Ytterbium-doped double clad optical fiber. Simultaneously, a pair of the fiber gratings that have high reflection at 1064nm was used to form the resonator of the fiber laser. Due to the poor coupling between the pumping source fiber and the pumping guide fiber, the conversion efficiency of fiber laser power to pumping power was only about 4% .
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Huang, Yu-ming, and 黃昱銘. "Fabrication of Cr-Doped Fiber by Drawing Tower." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/29806075607776021736.
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碩士國立中山大學
光電工程研究所
94
Abstract The breakthrough technology in dry fiber fabrication has opened the possibility for using fiber bandwidths all the way from 1.3 to 1.6 μm. The fiber amplifier that is in common use can not fully cover the whole, which its range is from 1.3 to 1.6 μm. Recently, the Cr4+-doped fiber has shown a broadband emission from 1.3 to 1.6 μm. Therefore, it is eminently suitable for super-wideband optical source. In this study, we first propose and fabricate a Cr4+-doped fiber by employing a commercial drawing-tower method, which has good core diameter uniformity, the growth speed is up to 200 m/min, and the core diameter is less than 10 μm. The central wavelength of the ASE spectrum is at 1310 nm, and a 3-dB bandwidth is 300 nm. The divergent angle of the Cr-doped fiber is 17 o × 15 o and it’s also similar to a single mode fiber of 16 o × 16 o. Low-loss fusion splice can readily be done with the standard single mode fiber, and is beneficial when integrated with the broadband WDM couplers. Therefore, it is good for commercial production and application to light wave systems.
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Yang, Jing. "Numerical modeling of hollow optical fiber drawing process." 2008. http://hdl.rutgers.edu/1782.2/rucore10001600001.ETD.17240.
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Shr, Ren-chin, and 施仁親. "Drawing of silica photonic crystal fiber by LHPG method." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/03718817353118235709.
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碩士國立中山大學
光電工程研究所
94
Semiconductor has electronic bandgap because of the periodic potential barriers. Similarly, as shown in Yablonovitch and John’s original idea in 1987, and the optical bandgap can be formed by arranging the dielectric material periodically, named photonic crystal. The innovation promotes vigorous development in the last twenty years. Many applications were discovered by using the idea of photonic crystal, such as waveguide, left-hand material, slow light, optical register, etc. Conventional fibers guide light in the core by the total internal reflection principle, but Russel and co-workers demonstrated fibers with a so-called photonic crystal cladding in 1996, and these fibers guide light by a new physical mechanism different from traditional fibers. Photonic crystal fibers can be simply divided into two groups, one is index guiding fiber and the other is photonic bandgap fiber. Both of them have 2D periodic structures with designed defect structure in the center. Hence light can be confined and guided by special defect modes. We have successfully demonstrated microstructured fibers which have 2D periodic structure by LHPG method. During the fabrication processes, capillaries may collapse due to the surface tension. We discuss the hole-collapse issue and our solution. Besides, the quality of fiber extremely depends on the stability of laser power of the LHPG system, so we design an efficient feedback control to improve it. We also discuss the fibers’ SEM images and optical properties. Finally the future work refers to the drawing of 3D photonic crystal fiber and improving the sharp thermal gradient by using a sapphire tube.
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HUANG, CHI-FEI, and 黃頎菲. "Microstructure Changes of 316L Stainless Steel Fiber after Multi-pass Drawing." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/wjvd5k.
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博士逢甲大學
纖維與複合材料學系
106
In recent years, 316L stainless steel wire is frequently applied in intelligent and communicative textile structures of wearable devices and smart clothing. Due to 316L stainless steel is the medical grade and biocompatible material in series of austenitic stainless steel, and its non-toxic, conductivity, rustproof, chemical resistance, and heat resistance. In order to light the wearable devices and improve comfortableness and soft hand feel of 316L stainless steel fabrics. The diameter of 316L stainless steel wire is reduced to the size in micrometer by multi-pass drawing process and form 316L stainless steel fiber. However, a few of studies discussed about the effect to the microstructure and properties of 316L stainless steel fiber by multi-pass drawing process. Therefore, three parts in this study are discussed: (1) Crystalline phase and mechanical property of austenite stainless steel fibers after multipath cold drawing and heat treatment processes; (2) Magnetic anisotropy of ultrafine 316L stainless steel fibers; (3) Characterization of microtexture of 316L stainless steel fiber after multi-pass drawing by electron backscatter diffraction. The first part: The crystalline phase and mechanical property of 316L stainless steel fibers after two bundle drawing paths and heat treatment at 800 °C were discussed. The identification and quantification of 316L stainless steel fibers were analyzed by an X-ray diffractometer. Results show that 316L stainless steel fiber has γ-austenite and α'-martensite phases. The strain-induced martensitic transformation took place after a drawing process at room temperature. The α'-martensite phase of the fiber was increased with an increase of specific strength and a decrease of elongation of the fiber after a drawing process; whereas the α'-martensite phase of the fiber was decreased with a decrease of specific strength and an increase of elongation of the fiber after heat treatment at 800 °C. It can be seen that the process of heat treatment benefits the plastic deformation of austenite stainless steel fiber. The second part: The grain sizes of γ-austenite and α′-martensite were reduced to nanoscale sizes after the drawing process. XRD analysis and FIB-SEM observations showed that the newly formed α′-martensitic grains were closely arrayed in the drawing direction. The magnetic property was measured using a SQUID-VSM sample magnetometer. The magnetic anisotropy of the fibers was observed by applying a magnetic field parallel and perpendicular to the fiber axis. The results showed that the microstructure anisotropy including the shape anisotropy, magnetocrystalline anisotropy, and the orientation of the crystalline phases strongly contributed to the magnetic anisotropy. The third part: The microstructure and microtexture of 316L stainless steel fibers after multi-pass cold drawing with intermediate heat treatment were investigated in this study. The crystalline phases of SSFs were identified and quantified using X-ray diffraction analysis. Grain orientation and boundary characterization in the mantle and core regions of drawing direction (DD) were analyzed through electron backscatter diffraction (EBSD). The coincident site lattice approach provides beneficial information for defining twin boundary and analyzing the orientation relationship between neighboring grains on the Σ3 segment. Three crystalline phases, γ, α, and σ, could be seen in XRD profiles. The formation mechanism of deformation twins was found, and two types of twin boundaries were observed in the drawn fibers by EBSD. The twin boundary generated between a {112}〈111〉 grain and a 〈100〉//DD grain is believed to nucleate at a high-angle grain boundary and then bulge into the {112}〈111〉grain.
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Chang, Chia-Shou, and 張家壽. "Development and Analysis of Micro Wavelength-Division Multiplexer with Improved Fiber-Drawing Process." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/77339537509527821440.
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碩士國立臺灣大學
光電工程學研究所
95
Minimizing the waveguide is very important in optical communications as the semiconductor components become smaller and smaller, but the fabrication of low-loss optical waveguides with sub-wavelength diameters remains challenging. In this work, we utilized an improved drawing tower to obtain the silica micro/nano optical wires (MNOWs) with several micrometers or several hundred micrometers. The MNOWs had extremely good diameter uniformity with long length up to tens of centimeters, and they were properly handled with a tungsten needle. The tip of a fiber taper could be attached to a guiding silica wire because of van der Waals attraction between the two, and the power was launched into these wires by evanescent wave. Also, the wires had an average optical loss of less than 1.0dB/mm. Furthermore, we successfully assembled the connection between a fiber taper and an MNOW by UV glue in air to simplify the package process. We used the waveguide simulation software to design the micro wavelength division multiplexer (MWDM) suitable for 980/1550nm light wave, and the MWDM had a high wavelength separation ratio.
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Chang, Chia-Shou. "Development and Analysis of Micro Wavelength-Division Multiplexer with Improved Fiber-Drawing Process." 2007. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-2007200716120800.
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Jiang, Hung-Bin, and 江宏斌. "Drawing Properties of Ultrahigh Molecular Weight Polyethylene Fiber Prepared at Varying Formation Temperatures." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/64907726730521435189.
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碩士國立臺灣科技大學
纖維及高分子工程系
90
The research investigated the influence of formation temperature on the spinning and extensible properties of the UHMWPE/LMWPE gel fibers. At the first we discussed when the formation temperature about 10℃ the achievable draw ratio approached the maximum. When formation temperature cool down the birefringence, crystallinity, thermal and tensile properties of the as-spun fiber sample were changed. It is interesting the achievable draw ratio of the sample by two section different temperature extended and the first draw ratio （D1r）and the second extended temperature （Tsec）were correlate in the optimum formation temperature. The optimum sample UL10℃ by the optimum D1r and Tsec to got the optimum achievable draw ratio（Draop）was higher about 25﹪than first extended in the same temperature 95℃（161 vs 126）and the tensile data about 130g/d.We can discussed those interesting state by the birefringence, crystallinity, thermal and tensile properties.
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Wu, Bo-Shen, and 吳博申. "Applying Taguchi Method to Improve Experimental Efficiency of Polyacrylonitrile Fiber Hot Drawing Process." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/3w59pu.
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碩士國立虎尾科技大學
工業工程與管理研究所
102
Now technology is increasingly developed, experiments in various domains are increasingly complex, thus relatively experimental cost and time used are increasingly getting higher, so the study aims at using Taguchi method applied to experiment for synthetic fiber process to reduce experiment times and enhance experimental efficiency. The study takes acrylic strand hot drawing process as example, applies Taguchi orthogonal table to experimental process, by means of setting control factors and levels, to evaluate their importance of effect in acrylic strand hot elongation process, and considering interaction effect among factors, so that accuracy of experimental prediction can be enhanced, and further conducts small range experiment with evaluated experimental combinations, to find out possible preferred parameter combinations in the process, thereby effect of reducing experimental cost can be achieved. The study considers interaction effects among factors, the prediction results in the study has enhanced prediction accuracy comparing to that of interaction effects among factors not considered. From experiment, it is found that prediction with interaction effects among factors considered is more accurate, the same experimental results of 30 times of experiments are the same as results of 48 time, through the experiments, it is found that Taguchi method is capable of effectively enhancing experimental efficiency, reducing experiment cost, and thereby it can be provided for reference in experiments of other processes in synthetic fiber processing plants.
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Chuang, Yu-kuei, and 莊玉桂. "The Research of Censorship on Architectural Fire Engineering Equipment Design Drawings and Fire BIM built." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/2327n9.
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碩士國立臺北科技大學
土木與防災研究所
101
Architectural engineering design become increasingly diversified, with the highly developed city, the population density and the floor increased use of improved demand and importance for the lives and property, fire-fighting equipment in the project occupies a very important position, and fire-fighting equipment planning and design stage drawings carefully considered, tend to project the overall execution results have a dramatic effect, a good planning and design of the case, allow the job to be smooth to conduct; Conversely, it may allow the construction phase problem in an endless stream, we can see construction life cycle, planning and design stage is the key to project success. Planning and design professionals such as architects, fire protection equipment engineer, each focused on building codes, fire safety regulations set standards in different areas, resulting in architectural design results often appear with fire-fighting equipment engineering interface integration issues, fire and fire BIM (building Information Modeling) drawings review the building, in order to ensure that the construction project planning and design quality, effective interface coordination, engineering changes designed to reduce the risk, can effectively eliminate the inconsistent planning design, omission, conflict or wrong question, to avoid extension of time, performance controversy and generate mediation, arbitration or litigation circumstances. Construction planning and design of fire-fighting equipment and fire BIM drawings examine the building to the CPA (Construction and Planning Agency) 100 to 101 years of professional agents throughout the construction, for example, according to the latest revised "set of Fire Safety Equipment Standards", accompanied by reviewing case construction interface checks, collection and fire operation unit examined the differences, and BIM explore equipment and pipelines collisions, serve free project contracts after processing design changes affect the quality of construction, I hope this paper the relevant information and recommendations, to provide construction project planning, design and review of fire-fighting equipment by reference.
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Hu, Chun-chieh, and 胡俊傑. "Structure and Mechanical Property of Ni-Cu Alloy Fiber after Drawing and Annealing Treatments." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/55279378581978325582.
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Chuo, Shih-Min, and 卓士閔. "Fabrication of Micro/Nano Optical Wires Using the Miniaturization of Fiber Drawing Tower and Their Applications." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/61614863010016669514.
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博士國立臺灣大學
光電工程學研究所
100
Micro/nano optical wires (MNOWs) were fabricated from an optical fiber preform drawn down to several micrometers (0.5~10 μm) in diameter by the modified fiber drawing tower. MNOWs are flexible, low propagation loss and capable of being mass producted, which can be used to substitute the waveguiding media in various optical devices to miniaturize their size or change their performance. The fiber preform was passed through the furnace with the temperature of 1400~1600℃ and then attached to the feeding and drawing mechanisms. When it was melted by the furnace, different diameters of MNOWs can be drawn by changing the speed ratio of feeding and drawing sides with the calculation of principle of mass conservation. This method can draw the MNOW with 165 cm in length, much longer than other methods (10 cm). Besides, theoretically the MNOW can have the minimal diameter variation after the drawing process becomes stable, providing the possibility of achieving the lowest propagation loss. The effective indices, intensity distribution, optical characteristics and degradation of microfiber were simulated and measured, respectively. The propagation loss of MNOWs we made nowadays is about 0.002 dB/mm, which does not reach the value of conventional optical fiber but can be improved. Furthermore, such an MNOW can be applied to microfiber-based devices with various performances. The MNOW has the strong guiding mechanism and can be easily influenced by the surrounding contaminations. Therefore we tried to use polydimethylsiloxane (PDMS) as the coating material to embed it into a cylindrical layer. It was found that there was no observable degradation after the fabrication of 18 hours. These experimental results imply that the MNOW has the potential to be fabricated to fiber-like devices with mass production capability and long-term reliability. After the fabrication of various microfiber-based devices, we need a technique to connect one another to realize complete functions and performances. Therefore the splicing technique of MNOWs is the best choise. Two MNOWs were attached to each other by van der Waals force and then the coupling region was heated by electric arc. Under the condition of suitable distance, electric current and time, two MNOWs could be melted and form an MNOW. The splicing loss could be down to 0.16 dB, enough for the demand of connecting two devices. Considering microfiber-based devices, we tried to apply MNOWs to optical interconnects. MNOW has the propagation loss lower than that of the silicon waveguide (0.1 dB/mm) and could be used as optical waveguide in photonic integrated circuit. The positions of MNOWs were patterned by optical lithography and therefore the performance could be controlled exactly and repeatability could be obtained. Moreover, due to the way of placement, it had the potential of achieving three dimensional optical interconnect. The patterned grooves were fabricated on PDMS and the MNOWs were placed into it to form the micro-ring resonator with the Q value of 104. This result was similar to that made from silicon as guiding medium, implying the MNOW is feasible of replacing silicon waveguide Another application of MNOW is corrugated long period microfiber grating (C-LPMFG). Fiber sensors have the characteristic of electromagnetic immunity, i.e., many sensors can be placed together without interfering each other. However, the size of fiber sensor limits its application to be placed into small region. Hence we need a microfiber-based grating. The optical fiber was fabricated with surface corrugated periodical structures by using semiconductor process. Due to strong guiding characteristic the MNOW can become C-LPMFG, which can be used as refractive index and temperature sensors. In particular, because of the modes in MNOW is different from that of optical fiber, it has higher sensitivity of approximately 2100 nm/RIU when sensing surrounding refractive index. Besides, the fabrication method of C-LPMFG enables it to be simultaneously made for a large amount, representing mass production ability. Microfiber, as a burgeoning research topic, is studied for its characteristics and applications by many research groups, and we are one of them. We developed the fabrication method using modified fiber drawing tower to make much longer MNOW and the coating method was also presented. For the applications, we tried the feasibility of using MNOW into optical interconnect and, on the other hand, made it into C-LPMFG with high sensitivity. These results show that MNOW can be used in various optical devices with good properties, which is the future star in the field of optoelectronics.
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CHIANG, MEI-CHUAN, and 江美娟. "The Investigation on the Influence of Auxiliary Application in Auditing Fire Drawings - Based on Carbon Dioxide Fire Extinguishing System." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/a3vm85.
Full textAbstract:
碩士大葉大學
環境工程學系碩士在職專班
105
Despite the fire drawing auditing in Taiwan has already included internet registration in order to utilise computer to proceed auditing, however the auditing process are still relied on human power which is a waste thus its accuracy cannot be ensured. This investigation is based on carbon dioxide fire extinguishing equipment, aiding by Autocad re-programmed software to help the authorities in fire drawing flaw detecting , calculation examine and facilities check up. The study has referred to Technology Acceptance Model 2 (TAM2) to develop its structure and made customised surveys with North region fire department, fire protection technician and dealer together with interviews done by ex-fire-fighting expertise and authorities on duty. The feasibility of application mentioned turns out to be verified as the result brings out that they all agree with the investigation's advantages. According to the study, the auditing of auxiliary application’s steps are standardisation, stylised and digitisation according to sequence. Although information technology are matured enough to deal with flaw detection, statistics, calculation and verification of original file, there is no scale on the calculation of flow, piping friction loss in presence law. The efficiency of fire drawing auditing shall be improved as the auxiliary application is applied when the circumstances is well-developed. Key Words : fire drawings auditing, auxiliary application, carbon dioxide fire extinguish equipment
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劉俊宏. "An application of the neural network system to the control and tune-up of optical fiber drawing process." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/72220774284219204343.
Full textAbstract:
碩士國立交通大學
科技管理所
90
The drawing process of optical fiber is a sequential process. Because of its high production speed, when running, every second is very important to fiber drawing or there will be lots of wastes produced. It is not only time and money waste but also, what is more important, many other costs that can’t be estimated. Therefore, it is absolutely important to be able to predict the quality of products and to know the relationship between parameter tuning and quality. The purpose of this research is to predict the statuses of process, then make use of the results we get to make a 1st-step quality certification and take a reference of parameter tuning and control, so that we can ensure the best condition of the process and get the best quality of products. The whole processes can be regarded as one process; in short, there is no one parameter interacts with no other parameter, but we can only say different level of interactions. Therefore, in the beginning in order to find proper methodology to deal with this sequential process problem, after considering the actual problems we encountered and comparing the other methodologies, we decided to use the neural network system. Although the advantages of the neural network system include very good abilities in accuracy and error tolerance, but taking time to train and regarding as a "black box" methodology, made it is not easy to get information during the process, are its defects; however, in process prediction and parameter tuning and control, there are also advantages to use neural network. We can get suitable accuracy by applying the neural network proposed in this research to drawing process. We can get the MError value under 0.001 between the desired and expected value in the drawing process. When we input the input signal with half of its whole range as noise into trained neural network, there are still 4 input parameters'' MError less than 0.001, and 1 less than 0.0013, and the remaining one less than 0.003 in the sensitivity analysis. After comparing with actual process circumstance, the accuracy is quite enough, hence, if we can restrict the input parameter to the half of whole range of the values, we can surely produce good quality products, and in fact this kind of control is achievable without doubt.
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Xu, Yue-Ji, and 許耀基. "The study on the physical properties and structure of melting spinning and multistage drawing high density polyethylene fiber." Thesis, 1989. http://ndltd.ncl.edu.tw/handle/40550294370473943413.
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GUO, SONG-LIN, and 郭松林. "A study ofthe structure development and physical properties of polypropylene fiber by melting spinning under multi-step drawing process." Thesis, 1992. http://ndltd.ncl.edu.tw/handle/89898131260540773937.
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