Modelling and Simulation in Materials Science and Engineering, Dec 13, 2018
This paper concerns uniaxial compression of anisotropic fibre network, as typically seen in the e... more This paper concerns uniaxial compression of anisotropic fibre network, as typically seen in the end use of nonwoven and textile fibre assemblies. The constitutive relationship and deformation mecha ...
Nano-cellulose fibres in suspension/gel states are known to have complex structures, depending on... more Nano-cellulose fibres in suspension/gel states are known to have complex structures, depending on, e.g., concentration and ionic strength. These complex structures pose both opportunity (creating novel functional structures) and challenges (difficult rheology and processability). To better assess their impacts on the formation of nano-cellulose structures, a novel particle-based method has been proposed based on Smoothed Dissipative Particle Dynamics. This numerical approach treats both fluid and solid phases, in a unified way, as a set of particles exchanging momentum and/or interacting through Derjaguin-Landau-Verwey-Overbeek (DLVO) potentials. Additionally, nano-cellulose fibres are represented as strings of solid particles connected through extensional/bending springs. Brownian motion is also accounted for as a dissipative term. Preliminary results already showed that self-assembled structures created by the nano-cellulose fibres are extremely sensitive to the type of interactions (e.g., electrostatic force interactions), the intensity and spatial distance of the interactions, and the concentration and configuration of nano-cellulose fibres. By using this method, it is thus possible to investigate the Figure 2-Simulation predictions of the viscosity increase as a function of fibre content for two different double layer thicknesses (κ-1). The data can be well fitted by Krieger-Dougherty correlation, showing that the method is able to reproduce expected trends.
One of the most well-known theories in the area of paper is probably Page's theory of tensile... more One of the most well-known theories in the area of paper is probably Page's theory of tensile strength. The article was published in Tappi Journal in 1969 [1], and written, in a very articulate way ...
Print quality is highly dependent on the interactions of paper, ink and printing plate at the len... more Print quality is highly dependent on the interactions of paper, ink and printing plate at the length scales of half-tone dot size and floc size. Knowledge of the details of the micro-structure is needed to predict these interactions, but it is difficult to obtain experimentally. One way to recreate the micro-structures of paper and to gain understanding of the mechanisms behind their formation is to systematically model each unit process of papermaking at particle level. The output of such simulations is numerical descriptions of the three-dimensional paper structure, from which any structural data can be accessed. Consequently, the simulations relate process parameters and particle properties directly to the micro-structures of paper. Many characteristics of the fiber network structure and the distribution of fillers and fines are determined in the headbox and during drainage in the forming section. A model for fiber suspensions, which couples the Navier-Stokes equations to a mechanical model of discretely represented flexible fibers, has been developed. Its performance allows for the study of large particle systems at very high Reynolds numbers (20000 particles at Re=40000), which is enough to model the conditions prevalent in the forming section of a modern paper machine.
History-dependent dimensional behavior of paper has been formulated within the framework of the g... more History-dependent dimensional behavior of paper has been formulated within the framework of the general linear theory of viscoelasticity and the classical lamination theory. The effect of the drying history of the papermaking process was incorporated by introducing the "residual stress" in the reference configuration which was taken at the final drying stage in this study. This permits us to account for complex dimensional and form changes of paper in the converting and end use processes. In order to determine the prediction performance of the computer simulation model developed, in-plane and out-of-plane dimensional responses under cyclic humidity changes were predicted on the basis of hygroviscoelastic data of paper. The simulation examples demonstrated typical irreversible dimensional responses of paper both for the in-plane dimensional change and the curvature change (curl). The computer code can easily deal with the non-uniform distribution of 1) anisotropic viscoelastic properties, 2) hygrothermal properties, and 3) moisture and temperature through the thickness.
This keynote speech was given at the "Progress in Paper Physics Seminar", which was hel... more This keynote speech was given at the "Progress in Paper Physics Seminar", which was held in Montreal, Canada in 2010. This was Derek's last speech at an international paper physics conference. The ...
The validity of accelerated aging tests to predict and rank papers on their permanence has been u... more The validity of accelerated aging tests to predict and rank papers on their permanence has been under question, preventing the development of performance-based standards for permanent paper. We conducted a general kinetic analysis to investigate the aging process of paper. A general kinetic model is proposed to describe the depolymerization of cellulose. Experimentally it was shown that in the case of aging, cellulose degradation follows classic first-order kinetics as a special case of our general kinetic model. The Arrhenius equation was critically re-examined for the case of a multiple reaction system. It was shown analytically that the Arrhenius equation is still applicable when certain conditions are met. This was convincingly supported by experimental results. We also analysed the dependence of the degradation rate on the moisture content and hydrogen ion concentration. By conducting systematic experiments on these two factors, a general and quantitative relationship was established to explain the contribution of each factor and their interactions. Finally, based on this kinetic analysis, the effects of storage conditions on the life expectancy of paper were estimated.
This keynote speech was given at the "Progress in Paper Physics Seminar", which was hel... more This keynote speech was given at the "Progress in Paper Physics Seminar", which was held in Montreal, Canada in 2010. This was Derek's last speech at an international paper physics conference. The ...
Nano-cellulose fibres in suspension/gel states are known to have complex structures, depending on... more Nano-cellulose fibres in suspension/gel states are known to have complex structures, depending on e.g. concentration and ionic strength. These complex structures pose both opportunity and challenges: creating novel functional structures is challenged by difficult rheology and processability of NFC suspensions. To better assess the chemical and rheological impacts on the formation of nano-cellulose structures, we propose a novel particle-based method based on smoothed dissipative particle hydrodynamics. This numerical approach treats both fluid and solid phases in a unified way. Both fluid and solid phases are described as a set of particles exchanging momentum and/or interacting through Derjaguin-Landau-Verwey-Overbeek (DLVO) potentials. Additionally, nano-cellulose fibres are represented as strings of solid particles connected through extensional/bending springs. Brownian motion is also accounted for as a dissipative term. We used this model to simulate the micro rheology of NFC su...
Modelling and Simulation in Materials Science and Engineering, Dec 13, 2018
This paper concerns uniaxial compression of anisotropic fibre network, as typically seen in the e... more This paper concerns uniaxial compression of anisotropic fibre network, as typically seen in the end use of nonwoven and textile fibre assemblies. The constitutive relationship and deformation mecha ...
Nano-cellulose fibres in suspension/gel states are known to have complex structures, depending on... more Nano-cellulose fibres in suspension/gel states are known to have complex structures, depending on, e.g., concentration and ionic strength. These complex structures pose both opportunity (creating novel functional structures) and challenges (difficult rheology and processability). To better assess their impacts on the formation of nano-cellulose structures, a novel particle-based method has been proposed based on Smoothed Dissipative Particle Dynamics. This numerical approach treats both fluid and solid phases, in a unified way, as a set of particles exchanging momentum and/or interacting through Derjaguin-Landau-Verwey-Overbeek (DLVO) potentials. Additionally, nano-cellulose fibres are represented as strings of solid particles connected through extensional/bending springs. Brownian motion is also accounted for as a dissipative term. Preliminary results already showed that self-assembled structures created by the nano-cellulose fibres are extremely sensitive to the type of interactions (e.g., electrostatic force interactions), the intensity and spatial distance of the interactions, and the concentration and configuration of nano-cellulose fibres. By using this method, it is thus possible to investigate the Figure 2-Simulation predictions of the viscosity increase as a function of fibre content for two different double layer thicknesses (κ-1). The data can be well fitted by Krieger-Dougherty correlation, showing that the method is able to reproduce expected trends.
One of the most well-known theories in the area of paper is probably Page's theory of tensile... more One of the most well-known theories in the area of paper is probably Page's theory of tensile strength. The article was published in Tappi Journal in 1969 [1], and written, in a very articulate way ...
Print quality is highly dependent on the interactions of paper, ink and printing plate at the len... more Print quality is highly dependent on the interactions of paper, ink and printing plate at the length scales of half-tone dot size and floc size. Knowledge of the details of the micro-structure is needed to predict these interactions, but it is difficult to obtain experimentally. One way to recreate the micro-structures of paper and to gain understanding of the mechanisms behind their formation is to systematically model each unit process of papermaking at particle level. The output of such simulations is numerical descriptions of the three-dimensional paper structure, from which any structural data can be accessed. Consequently, the simulations relate process parameters and particle properties directly to the micro-structures of paper. Many characteristics of the fiber network structure and the distribution of fillers and fines are determined in the headbox and during drainage in the forming section. A model for fiber suspensions, which couples the Navier-Stokes equations to a mechanical model of discretely represented flexible fibers, has been developed. Its performance allows for the study of large particle systems at very high Reynolds numbers (20000 particles at Re=40000), which is enough to model the conditions prevalent in the forming section of a modern paper machine.
History-dependent dimensional behavior of paper has been formulated within the framework of the g... more History-dependent dimensional behavior of paper has been formulated within the framework of the general linear theory of viscoelasticity and the classical lamination theory. The effect of the drying history of the papermaking process was incorporated by introducing the "residual stress" in the reference configuration which was taken at the final drying stage in this study. This permits us to account for complex dimensional and form changes of paper in the converting and end use processes. In order to determine the prediction performance of the computer simulation model developed, in-plane and out-of-plane dimensional responses under cyclic humidity changes were predicted on the basis of hygroviscoelastic data of paper. The simulation examples demonstrated typical irreversible dimensional responses of paper both for the in-plane dimensional change and the curvature change (curl). The computer code can easily deal with the non-uniform distribution of 1) anisotropic viscoelastic properties, 2) hygrothermal properties, and 3) moisture and temperature through the thickness.
This keynote speech was given at the "Progress in Paper Physics Seminar", which was hel... more This keynote speech was given at the "Progress in Paper Physics Seminar", which was held in Montreal, Canada in 2010. This was Derek's last speech at an international paper physics conference. The ...
The validity of accelerated aging tests to predict and rank papers on their permanence has been u... more The validity of accelerated aging tests to predict and rank papers on their permanence has been under question, preventing the development of performance-based standards for permanent paper. We conducted a general kinetic analysis to investigate the aging process of paper. A general kinetic model is proposed to describe the depolymerization of cellulose. Experimentally it was shown that in the case of aging, cellulose degradation follows classic first-order kinetics as a special case of our general kinetic model. The Arrhenius equation was critically re-examined for the case of a multiple reaction system. It was shown analytically that the Arrhenius equation is still applicable when certain conditions are met. This was convincingly supported by experimental results. We also analysed the dependence of the degradation rate on the moisture content and hydrogen ion concentration. By conducting systematic experiments on these two factors, a general and quantitative relationship was established to explain the contribution of each factor and their interactions. Finally, based on this kinetic analysis, the effects of storage conditions on the life expectancy of paper were estimated.
This keynote speech was given at the "Progress in Paper Physics Seminar", which was hel... more This keynote speech was given at the "Progress in Paper Physics Seminar", which was held in Montreal, Canada in 2010. This was Derek's last speech at an international paper physics conference. The ...
Nano-cellulose fibres in suspension/gel states are known to have complex structures, depending on... more Nano-cellulose fibres in suspension/gel states are known to have complex structures, depending on e.g. concentration and ionic strength. These complex structures pose both opportunity and challenges: creating novel functional structures is challenged by difficult rheology and processability of NFC suspensions. To better assess the chemical and rheological impacts on the formation of nano-cellulose structures, we propose a novel particle-based method based on smoothed dissipative particle hydrodynamics. This numerical approach treats both fluid and solid phases in a unified way. Both fluid and solid phases are described as a set of particles exchanging momentum and/or interacting through Derjaguin-Landau-Verwey-Overbeek (DLVO) potentials. Additionally, nano-cellulose fibres are represented as strings of solid particles connected through extensional/bending springs. Brownian motion is also accounted for as a dissipative term. We used this model to simulate the micro rheology of NFC su...
Uploads
Papers by Tetsu Uesaka