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1. Geometric Mechanics of Curved Crease Origami.

Author

Dias, Marcelo A., Dudte, Levi H., Mahadevan, L., and Santangelo, Christian D.

Subjects
*COMPUTER simulation, *PAPER, *ASYMPTOTIC expansions, *CURVATURE, *OSCILLATIONS, *SYMMETRY breaking, *TORSION
Abstract

Folding a sheet of paper along a curve can lead to structures seen in decorative art and utilitarian packing boxes. Here we present a theory for the simplest such structure: an annular circular strip that is folded along a central circular curve to form a three-dimensional buckled structure driven by geometrical frustration. We quantify this shape in terms of the radius of the circle, the dihedral angle of the fold, and the mechanical properties of the sheet of paper and the fold itself. When the sheet is isometrically deformed everywhere except along the fold itself, stiff folds result in creases with constant curvature and oscillatory torsion. However, relatively softer folds inherit the broken symmetry of the buckled shape with oscillatory curvature and torsion. Our asymptotic analysis of the isometrically deformed state is corroborated by numerical simulations that allow us to generalize our analysis to study structures with multiple curved creases. [ABSTRACT FROM AUTHOR]

Published
2012
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2. Scaling and Noise in Slow Combustion of Paper

Author

J. Timonen, Tapio Ala-Nissila, J. Maunuksela, Mikko J. Alava, Markko Myllys, Perustieteiden korkeakoulu, School of Science, Teknillisen fysiikan laitos, Department of Applied Physics, Aalto-yliopisto, and Aalto University

Subjects
Physics, paper, General Physics and Astronomy, High resolution, Function (mathematics), Kinetic energy, Combustion, Amplitude, Range (statistics), Statistical physics, kinetic roughening, Scaling, Noise (radio)
Abstract

We present results of high resolution experiments on kinetic roughening of slow combustion fronts in paper, focusing on short length and time scales. Using three different grades of paper, we find that the combustion fronts show apparent spatial and temporal multiscaling at short scales. The scaling exponents decrease as a function of the order of the corresponding correlation functions. The noise affecting the fronts reveals short range temporal and spatial correlations, and non-Gaussian noise amplitudes. Our results imply that the overall behavior of slow combustion fronts cannot be explained by standard theories of kinetic roughening.

Published
2000

3. Kinetic Roughening in Slow Combustion of Paper

Author

Mikko J. Alava, J. Maunuksela, Markko Myllys, Juha Merikoski, Tapio Ala-Nissila, J. Timonen, Perustieteiden korkeakoulu, School of Science, Teknillisen fysiikan laitos, Department of Applied Physics, Aalto-yliopisto, and Aalto University

Subjects
Physics, Statistical Mechanics (cond-mat.stat-mech), paper, Crossover, FOS: Physical sciences, General Physics and Astronomy, Disordered Systems and Neural Networks (cond-mat.dis-nn), Fixed point, Renormalization group, Condensed Matter - Disordered Systems and Neural Networks, Kinetic energy, Noise (electronics), Amplitude, Condensed Matter::Statistical Mechanics, Statistical physics, interface dynamics, slow combustion, kinetic roughening, Constant (mathematics), Scaling, Condensed Matter - Statistical Mechanics
Abstract

Results of experiments on the dynamics and kinetic roughening of one-dimensional slow-combustion fronts in three grades of paper are reported. Extensive averaging of the data allows a detailed analysis of the spatial and temporal development of the interface fluctuations. The asymptotic scaling properties, on long length and time scales, are well described by the Kardar-Parisi-Zhang (KPZ) equation with short-range, uncorrelated noise. To obtain a more detailed picture of the strong-coupling fixed point, characteristic of the KPZ universality class, universal amplitude ratios, and the universal coupling constant are computed from the data and found to be in good agreement with theory. Below the spatial and temporal scales at which a cross-over takes place to the standard KPZ behavior, the fronts display higher apparent exponents and apparent multiscaling. In this regime the interface velocities are spatially and temporally correlated, and the distribution of the magnitudes of the effective noise has a power-law tail. The relation of the observed short-range behavior and the noise as determined from the local velocity fluctuations is discussed., RevTeX v3.1, 13 pages, 12 Postscript figures (uses epsf.sty), 3 tables; submitted to Phys. Rev. E

Published
1997

4. Modifications of the mesoscopic structure of cellulose in paper degradation

Author

Agostina Congiu Castellano, Ralf Schweins, Marina Bicchieri, Giuseppe Arcovito, Mauro Missori, Carlo Castellano, Marco De Spirito, Massimiliano Papi, and Claudia Mondelli

Subjects
Paper, Materials science, Neutron diffraction, General Physics and Astronomy, DISCOLORATION, Neutron scattering, Microscopy, Atomic Force, Small-angle neutron scattering, Sizing, chemistry.chemical_compound, Neutron Diffraction, chemistry, Chemical engineering, Scattering, Small Angle, Degradation (geology), Cellulose, Small-angle scattering, Biological small-angle scattering, NEUTRON SCATTERING, ANCIENT
Abstract

Paper is the main component of a huge quantity of cultural heritage. It is primarily composed of cellulose that undergoes significant degradation with the passage of time. By using small angle neutron scattering (SANS), we investigated cellulose's supramolecular structure, which allows access to degradation agents, in ancient and modern samples. For the first time, SANS data were interpreted in terms of water-filled pores, with their sizes increasing from 1.61 nm up to 1.97 nm in natural and artificially aged papers. The protective effect of gelatine sizing was also observed.

Published
2006

5. Modifications of the mesoscopic structure of cellulose in paper degradation.

Author

Missori M, Mondelli C, De Spirito M, Castellano C, Bicchieri M, Schweins R, Arcovito G, Papi M, and Castellano AC

Subjects
Microscopy, Atomic Force, Neutron Diffraction, Scattering, Small Angle, Cellulose chemistry, Paper
Abstract

Paper is the main component of a huge quantity of cultural heritage. It is primarily composed of cellulose that undergoes significant degradation with the passage of time. By using small angle neutron scattering (SANS), we investigated cellulose's supramolecular structure, which allows access to degradation agents, in ancient and modern samples. For the first time, SANS data were interpreted in terms of water-filled pores, with their sizes increasing from 1.61 nm up to 1.97 nm in natural and artificially aged papers. The protective effect of gelatine sizing was also observed.

Published
2006
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