Nonsymmetrical modified chemical vapor deposition (N-MCVD) process (optical fibres)

Doupovec, J.; Yarin, Alexander L.

doi:10.1109/50.81970

Cited by 12 publications

(5 citation statements)

References 10 publications

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“…The time evolution of the surface-tension-driven collapse process is shown in figure 7. The resulting bow-tie-like shape (figure 7f) is in qualitative agreement with the one found experimentally (figure 6 in Doupovec & Yarin 1991). Unfortunately, in this experiment the exact parameters of the deposited layer are unknown, which does not allow us to make a quantitative check of the theory in this case.…”

Section: Methods Of Surface-tension-driven Collapsesupporting

confidence: 86%

“…The non-symmetrical modified chemical vapour deposition (N-MCVD) process, with the subsequent surface-tension-driven collapse, makes it possible to fabricate preforms with bow-tie shaped claddings (see the photograph in figure 6 in Doupovec & Yarin 1991). In this case the boundaries 4 and 4 in figure 2 may be taken approximately as circles, and the interface & as an ellipse with a semi-axes ratio 6 = CJC, satisfying the inequality (4.8) (see (3.94 e)).…”

Section: Methods Of Surface-tension-driven Collapsementioning

confidence: 99%

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Surface-tension-driven flows at low Reynolds number arising in optoelectronic technology

Yarin

1995

J. Fluid Mech.

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Some methods of formation of preforms for drawing of polarization-maintaining optical fibres are based on utilization of the surface tension of glass in the liquid state. Under the action of surface tension non-circular glass articles begin to flow, which results in formation of an anisotropic internal structure of the preforms. The hydrodynamic analysis of two such methods is given in the paper. Analytical solutions of the Stokes equations with linearized boundary conditions for the corresponding creeping surface-tension-driven flows of liquid glass are obtained. By means of these solutions a processing strategy may be predetermined with a view to a specific internal structure of the fibre, as well as to the required value of birefringence. The theoretical results are compared with experimental data and agreement is fairly good.

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Section: Methods Of Surface-tension-driven Collapsesupporting

confidence: 86%

Section: Methods Of Surface-tension-driven Collapsementioning

confidence: 99%

Surface-tension-driven flows at low Reynolds number arising in optoelectronic technology

Yarin

1995

J. Fluid Mech.

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“…In a sense, coelectrospinning may be viewed as a reincarnation or modification of established techniques in textile and optical fiber spinning, or ink-jet printing. [12][13][14][15] Co-electrospinning requires a polymer solution in the shell and either a polymer solution or a nonpolymeric Newtonian liquid or even a powder to fill the inner core. [6][7][8] The physical pattern of co-electrospinning comprises a compound droplet sustained at the edge of a coreshell nozzle; this compound droplet transforms into a compound Taylor cone with a core-shell jet issuing from its tip.…”

mentioning

confidence: 99%

“…Core−shell polymer nano- and microfibers were first manufactured in a two-stage process, which started with ordinary (single-nozzle) electrospinning of the core polymer (stage 1) and was followed by the coating deposition of the shell polymer (stage 2). − A reverse process of filling carbon nanotubes with pure liquids and suspensions also has resulted in core−shell nanostructures. , More recently, a single-stage process, called co-electrospinning, was introduced; it employed a compound coannular nozzle issuing core polymer solution from the inner tube and an annular coflow of a shell polymer solution. − Nano/micro fibers were produced with this process. In a sense, co-electrospinning may be viewed as a reincarnation or modification of established techniques in textile and optical fiber spinning, or ink-jet printing. − Co-electrospinning requires a polymer solution in the shell and either a polymer solution or a nonpolymeric Newtonian liquid or even a powder to fill the inner core. − The physical pattern of co-electrospinning comprises a compound droplet sustained at the edge of a core−shell nozzle; this compound droplet transforms into a compound Taylor cone with a core−shell jet issuing from its tip . As in the ordinary electrospinning process (reviewed in refs −23), the jet is simultaneously pulled, stretched, elongated, and bent by the electric forces.…”

mentioning

confidence: 99%

Co-electrospinning of Core−Shell Fibers Using a Single-Nozzle Technique

2007

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Co-electrospinning is ideally suited for fabricating continuous fibers encasing materials within a polymer sleeve, but requires relatively complex coannular nozzles. A single-nozzle co-electrospinning technique is demonstrated using blends of poly(methyl methacrylate) (PMMA)/polyacrylonitrile (PAN) solutions in dimethylformamide (DMF). The as-spun fibers have outer diameters in the range of 0.5-5 microm and possess a core-shell structure similar to that attained via coannular nozzles. The technique relies on the precipitation of PMMA solution droplets, which become trapped at the base of the Taylor cone issuing the PAN solution jet from its tip. A theoretical analysis shows that the outer shell flow is sufficiently strong to stretch the inner droplet into the Taylor cone, thus forming a core-shell jet. The method seems attractive for technological applications involving macroscopically long and radially inhomogeneous or hollow nano/micro fibers.

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“…5͒ or a nonsymmetric deposition process ͑N-MCVD͒. 6 Molten glass is a Newtonian fluid with a strong dependence of viscosity on temperature. Drawing of glass fibers is typically dominated by viscous forces modified by heating and cooling of the threadline.…”

Section: Introductionmentioning

confidence: 99%

Newtonian glass fiber drawing: Chaotic variation of the cross-sectional radius

et al. 1999

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A model of Newtonian glass fiber drawing at fixed temperature in the unsteady range ͑the draw ratio EϾ20.22) is considered. In this range under steady boundary conditions, as is well known, the draw resonance instability sets in, resulting in self-sustained oscillations. These oscillations lead to a periodic variation of the cross-sectional radius of the fiber. In the present work we consider the case where the spinline radius varies periodically. Such a variation may result from flow oscillations in the fiber forming channels in the direct-melt process, or from the variation of the preform cross-sectional radius in drawing of optical fibers. When this variation takes place in the range E Ͼ20.22, the self-sustained periodic oscillations of the draw resonance are replaced by quasiperiodic and periodic ͑mode-locked͒ subharmonic or ͑under the appropriate conditions͒ chaotic oscillations ͑strange attractors͒. The routes to chaos found in the present work include ͑1͒ smooth period doubling bifurcation of ͑any͒ mode-locked periodic solution, ͑2͒ abrupt explosions of quasiperiodic solutions. The predicted chaotic variation of the spinline radius at the winding mandrel may result in a similar variation of the cross-sectional radius of the solidified fibers.

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Nonsymmetrical modified chemical vapor deposition (N-MCVD) process (optical fibres)

Cited by 12 publications

References 10 publications

Surface-tension-driven flows at low Reynolds number arising in optoelectronic technology

Surface-tension-driven flows at low Reynolds number arising in optoelectronic technology

Co-electrospinning of Core−Shell Fibers Using a Single-Nozzle Technique

Newtonian glass fiber drawing: Chaotic variation of the cross-sectional radius

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