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- Edvardsson, Sverker, et al.
(författare)
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A Note on Wet Paper Web Adhesion Strength
- 2012
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Ingår i: Journal of Testing and Evaluation. - 0090-3973 .- 1945-7553. ; 40:4, s. 682-686
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Tidskriftsartikel (refereegranskat)abstract
- This work is concerned with the determination of the adhesion strength between a paper web and an adhesive surface. Edvardsson et al. [Edvardsson, S., Gradin, P., and Isaksson, P., "On Dissipative Effects of Paper Web Adhesion Strength," Int. J. Solids Struct., Vol. 48(1), 2011, pp. 24-30] suggested recently a model that takes into account the energy dissipation caused by elastic plastic deformation in the bent structure of a paper specimen. This model is further developed and investigated in the present work. A linear relation in plastic dissipation is discovered facilitating a novel analysis of the peeling tension and a more convenient determination of the proper adhesion strength. Industrial relevant examples are made with wet newsprint and kraft stock. A straightforward experimental procedure for determining the consistent adhesion strength is suggested. It is found that the agreement between the model and the experimental observations is good.
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| 2. |
- Edvardsson, Sverker, et al.
(författare)
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On dissipative effects of paper web adhesion strength
- 2011
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Ingår i: International Journal of Solids and Structures. - : Elsevier BV. - 0020-7683 .- 1879-2146. ; 48:1, s. 24-30
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Tidskriftsartikel (refereegranskat)abstract
- This work is concerned with the adhesion strength between a paper web and a metal roll surface, which is a common situation in paper machines world-wide. It is shown that the classic expression relating the work of adhesion to the peeling angle and web tension is, in general, insufficient. An improved model is suggested to take into account the energy dissipation due to elastic-plastic deformation behavior of wet paper materials. To judge the model, an industrially relevant example of wet newsprint and a mild steel surface is studied. It is found that the agreement between theory and experimental observations is excellent. A key result is that elastic-plastic material behavior must always be included for wet paper materials in peeling processes.
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| 3. |
- Edvardsson, Sverker, et al.
(författare)
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System dynamics of the open draw with web adhesion: Particle approach
- 2010
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Ingår i: Journal of applied mechanics. - : ASME International. - 0021-8936 .- 1528-9036. ; 77:2, s. 1-11
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Tidskriftsartikel (refereegranskat)abstract
- In the present work we propose a particle approach, which is designedto treat complex mechanics and dynamics of the open-draw sections thatare still present in many of today's paper machines. First, knownsteady-state continuous solutions are successfully reproduced. However,it is shown that since the boundary conditions depend on the solutionitself, the solutions for web strain and web path in the open-drawsection are generally time-dependent. With a certain set of systemparameters, the nonsteady solutions are common. A temporal fluctuationof Young's modulus, for example, destabilizes the system irreversibly,resulting in the continuous growth of web strain, i.e., break. Finallywe exemplify with some strategic draw countermeasures how to prevent adangerous evolution in the web strain.
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| 4. |
- Edvardsson, Sverker, 1964-, et al.
(författare)
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The dynamical functional particle method: an approach for boundary value problems
- 2012
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Ingår i: Journal of applied mechanics. - : ASME International. - 0021-8936 .- 1528-9036. ; 79:2, s. art. no. 021012-
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Tidskriftsartikel (refereegranskat)abstract
- The present work is concerned with new ideas of potential value for solving differential equations. First, a brief introduction to particle methods in mechanics is made by revisiting the vibrating string. The full case of nonlinear motion is studied and the corresponding nonlinear differential equations are derived. It is suggested that the particle origin of these equations is of more general interest than usually considered. A novel possibility to develop particle methods for solving differential equations in a direct way is investigated. The dynamical functional particle method (DFPM) is developed as a solution method for boundary value problems. DFPM is based on the concept of an interaction functional as a dynamical force field acting on quasi particles. The approach is not limited to linear equations. We exemplify by applying DFPM to several linear Schrödinger type of problems as well as a nonlinear case. It is seen that DFPM performs very well in comparison with some standard numerical libraries. In all cases, the convergence rates are exponential in time. © 2012 American Society of Mechanical Engineers.
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| 5. |
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| 6. |
- Hellström, Lisbeth M., et al.
(författare)
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A theoretical and experimental study of the circular sawing process
- 2014
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Ingår i: Holzforschung. - : Walter de Gruyter GmbH. - 0018-3830 .- 1437-434X. ; 68:3, s. 307-312
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Tidskriftsartikel (refereegranskat)abstract
- To gain further insight into the energy dissipation during the wood sawing process, a theoretical model has been developed. The model is based on the assumption that there are two basic causes for energy dissipation during sawing: the creation of a new surface and the compression of material below a saw tooth. It is assumed that both contributions can be dependent on the cutting angle (the angle between the fiber direction and the tangent to the path followed by a saw tooth) because a saw tooth changes its angle of attack during its way through a log. To determine this dependence of the dissipation on the cutting angle, a series of experiments with pine plank sawing were performed by means of different feeding rates and cutting angles while the electrical power supplied to the saw was measured. The parameters in the theoretical model were derived from the experimental findings. Finally, two tests were carried out under different conditions with respect to thickness and cutting angles and the validity of the model was confirmed concerning the prediction of the electrical power consumption.
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| 7. |
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| 8. |
- Zhang, Renyun, et al.
(författare)
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High-speed deposition of multilayer nanofilms using soap-film coating
- 2013
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Konferensbidrag (refereegranskat)abstract
- High-speed deposition of multilayer nanofilms using soap-film coatingRenyun Zhang, Henrik A. Andersson, Mattias Andersson, Britta Andres, Per Edström, Sverker Edvardsson, Sven Forsberg, Magnus Hummelgård, Niklas Johansson, Kristoffer Karlsson, Hans-Erik Nilsson, Martin Olsen, Tetsu Uesaka, Thomas Öhlund & Håkan OlinDepartment of Applied Science and Design, Mid Sweden University, SE-85170 Sundsvall, SwedenEmail: renyun.zhang@miun.se or hakan.olin@miun.seCoating1 of thin films is of importance for making functionalized surfaces with applications in many fields from electronics to consumer packaging. To decrease the cost, large scale roll-to-roll2 coating techniques are usually done at high speed, for example, ordinary printing paper is coated at a speed of tens of meters per second by depositing micrometer thick layers of clay. However, nanometer thin films are harder to coat at high speed by wet-chemical methods, requiring special roll-to-roll vacuum techniques3 with the cost of higher complexity.Here, we report a simple wet chemical method for high-speed coating of films down to molecular thicknesses, called soap-film coating (SFC)4. The technique is based on forcing a substrate through a soap film that contains nanomaterials. In the simplest laboratory version, the films can be deposited by a hand-coating procedure set up in a couple of minutes. The method is quite general molecules or nanomaterials or sub-micrometer materials (Figure 1) with thicknesses ranging from less than a monolayer to several layers at speeds up to meters per second. The applications of soap-film coating is quite wide an we will show solar cells, electrochromic devices, optical nanoparticle crystals, and nano-film devices. We believe that the soap-film coating method is potentially important for industrial-scale nanotechnology.Fig. 1. Soap film coating of nanoparticles, layered materials, nanowires, and molecules. a sub-monolayer 240 nm silica nanoparticle (scale bar 2 µm) b monolayer c double layer. d monolayer gold nanoparticles. e single layer TiO2 nanoparticles. f sub-monolayer polystyrene (scale 2 µm), g monolayer of polystyrene. h triple-layer of polystyrene. i monolayer of Ferritin. j AFM image of <1.5 layer GO film (3 µm x 2 µm). k clay on glass (scale 2 µm). l SFC coated nanocellulose. m Absorbance spectra Rhodamine B on a glass slide. AFM of SDS layers n (2 µm x 1.5 µm) and o (20 µm x 15 µm).ReferencesTracton, A. A. Coating Technology Handbook (CRC Press, Boca Raton, 2006).Ohring, M. Materials science of thin films. (Academic press., 2001).Charles, B. Vacuum deposition onto webs, films and foils. (William Andrew, 2011).Zhang, R. Y., Andersson, H. A., Andersson, M., Andres, B., Edström, P., Edvardsson, S., Forsberg, S., Hummelgård, M., Johansson, N., Karlsson, K., Nilsson, H.-E., Olsen, M., Uesaka, T., Öhlund, T., Olin H. Soap film coating: High-speed deposition of multilayer nanofilms. Submitted.
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| 9. |
- Zhang, Renyun, et al.
(författare)
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Piezoelectric gated ZnO nanowire diode studied by in situ TEM probing
- 2014
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Ingår i: Nano Energy. - : Elsevier. - 2211-2855. ; 3, s. 10-15
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Tidskriftsartikel (refereegranskat)abstract
- The piezoelectricity of ZnO nanowires has shown rising interests during the last few years and fields such as piezotronics and piezophotonics are emerging with a number of applications and devices. One such device is the piezoelectric gated ZnO nanowire diode, where the p–n junction is replaced by a dynamically created potential barrier created simply by bending the otherwise homogeneously doped nanowire. To further study this type of diode we used in situ transmission electron microscope (TEM) probing, where one electrode was fixed at the end of a ZnO nanowire and another moveable electrode was used both for bending and contacting the wire. Thereby we were able to further characterise this diode and found that the diode characteristics depended on whether the contact was made to the stretched (p-type) surface or to the compressed (n-type) surface of the wire. When the neutral line of the wire contacted, between the stretched and the compressed side, the I–V characteristics were independent on the current direction. The performance of the diodes upon different bending intensity showed a rectifying ratio up to the high value of 60:1. The diode ideality factor was found to be about 5. Moreover, the reverse breakdown voltages of the diode were measured and a local but permanent damage to the diode action was found when the voltage went over the reverse breakdown voltage.
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| 10. |
- Zhang, Renyun, et al.
(författare)
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Soap-film coating : High-speed deposition of multilayer nanofilms
- 2013
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Ingår i: Scientific Reports. - Nature Publishing Group : Springer Science and Business Media LLC. - 2045-2322. ; 3, s. Art. no. 1477-
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Tidskriftsartikel (refereegranskat)abstract
- The coating of thin films is applied in numerous fields and many methods are employed for the deposition of these films. Some coating techniques may deposit films at high speed; for example, ordinary printing paper is coated with micrometre-thick layers of clay at a speed of tens of meters per second. However, to coat nanometre thin films at high speed, vacuum techniques are typically required, which increases the complexity of the process. Here, we report a simple wet chemical method for the high-speed coating of films with thicknesses at the nanometre level. This soap-film coating technique is based on forcing a substrate through a soap film that contains nanomaterials. Molecules and nanomaterials can be deposited at a thickness ranging from less than a monolayer to several layers at speeds up to meters per second. We believe that the soap-film coating method is potentially important for industrial-scale nanotechnology.
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