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High speed very thin films with reverse roll coatings. An experimental investigation of reverse roll coating of fluids using rigid and deformable rolls at high speeds.Shibata, Yusuke January 2012 (has links)
The objective of a coating operation is to transfer a defect free liquid film
onto a continuous substrate in order to meet the requirements of the final products.
Mainly two concerns govern the process. The first concern is the economics of the
process and the second concern is the quality of the coated film. The economics of
the process are dictated by the speed of coating and the film thickness. Clearly,
higher speeds mean better productivity hence less cost of operation and thinner
films are desirable because less material is being used. Quality is governed by film
uniformity and integrity, indicating that the film will perform as designed. Film
defects such as streaks or tiny air bubbles are indication that the film properties are
not uniform rendering it unacceptable to customers. One of the most versatile
coating systems to achieve thin films at high speeds is reverse roll coating which has
been used for a long time all over the world. At low speed, typically 1m/s, this
coating operation is inherently stable and with small gaps of order 100 microns can
ii
lead to film thickness of order 30-50 microns. Much research, theoretical and
experimental, has been devoted to this coating flow but only at low speeds and for
large gaps (>100 microns). There are no comprehensive data how very thin films, 20
microns and less (particularly lower limits in the region of 5 microns) can be
achieved at high speeds, of 2 or more metres per second. This study is concerned
precisely with this aim, that of investigating the effect of large speeds and small
roller gaps (rollers nearly touching or in elastohydrodynamic contact) to achieve the
very thin films desired by modern applications (electronics, medical and others). In
order to achieve this aim, a rig was designed and built to enable to understand the
effect of various coating conditions and liquid properties on the metered film
thickness and coating instability. To achieve thin films at high speeds, small roll gap
and low viscosity are needed, however flow instabilities will develop under these
conditions. To achieve stable coating window at high speeds high surface tension is
needed. It was found that the roll gap and the viscosity have complicated effect on
the coating window. In the case of low viscosity liquid (7mPa.s), small roll gaps are
needed, whereas in the case of high viscosity liquid (more than 30mPa.s), large gaps
are needed. It was found that Weber number is better describer for ribbing
instability in rigid reverse roll coating unlike in rigid forward roll coating in which
capillary number is the one.
In addition the potential of reverse deformable roll coating (rolls in
elastohydrodynamic contact) was investigated in order to achieve much thinner
films at higher speeds. As a result of the investigation of reverse deformable roll
coating, it was found that there is a possibility to get much thinner stable films at
much higher speeds compared to reverse rigid roll coating. The liquid transfer from an applicator roller to a PET film was investigated in
this study. It was found that air stagnation at downstream meniscus and air
entrainment at upstream meniscus depend on the liquid properties such as viscosity
and surface tension and coating conditions such as web tension and wrap angle of
web. As a result, wet film instability also depends on liquid properties and coating
conditions. It was found that air stagnation causes streaks on the wet film and air
entrainment caused bubbles on the wet film. To get a stable wet film, it was found
that suitable viscosity and high surface tension were needed. / TOYOBO
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Predicting Moment and Rotation Capacity of Semi-rigid Composite Joints with Precast Hollowcore Slabs.Lam, Dennis, Ye, J., Fu, F. January 2009 (has links)
No description available.
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Variational Calculations of Lambda Binding Energies In Hypernuclei / Lambda Binding Energies in HypernucleiHo, Tze-Chien Hazel 10 1900 (has links)
<p> Variational calculations for hypernuclei and their corresponding nuclear cores have been performed with phenornenological effective Ʌ -N and N-N interactions. Effects of deformation and Majorana exchange on the Ʌ binding energies have been studied. The influence of density dependence in both the Ʌ-N and N-N force has been investigated . The three-body ɅNN interaction has also been considered qualitatively. All these effects help to reduce the Ʌ binding energies in hypernuclei. </p> <p> In addition to the variational calculations, the rigid alpha model has been used to determine the Ʌ binding energy in (5 Ʌ - He). A comparison of the methods is given. </p> Finally, excited states of some hypernuclei have been calculated using the variational ground state equilibrium size. </p> / Thesis / Doctor of Philosophy (PhD)
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Analytical Investigation of the Effect of Partially-Restrained Connections on Hybrid Moment-Resisting Steel FramesKozma Thomas, Mathias A. 13 October 2014 (has links)
No description available.
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Variable-Geometry Extrusion Die Synthesis and Morphometric Analysis Via Planar, Shape-Changing Rigid-Body MechanismsLi, Bingjue 24 August 2017 (has links)
No description available.
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Identification of Multi-Dimensional Elastic and Dissipation Properties of Elastomeric Vibration IsolatorsRamesh, Ram S. 02 August 2018 (has links)
No description available.
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STRENGTH DETERMINATION OF HEAVY CLIP-ANGLE CONNECTION COMPONENTSGAO, XIAOJIANG January 2002 (has links)
No description available.
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MODELING OF SLIP AND BEARING INTERACTIONS IN BOLTED CONNECTIONS SUBJECTED TO CYCLIC LOADINGOLTMAN, JONATHAN A. 08 October 2007 (has links)
No description available.
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Molecular/Nano Level Approaches for the Enhancement of Axial Compressive Properties of Rigid-Rod PolymersDang, Thuy Dinh 03 November 2009 (has links)
No description available.
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Field performance of dowel barsWalters, Shane A. January 1999 (has links)
No description available.
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