Search results for "deformation"

Triblock copolymers, mesogels and deformation behavior in poor solvents

2007

A fundamental distinction between the mesophases formed by ABA triblock copolymers and by AB diblock copolymers is the bridging of A domains by B blocks. The ABA mesophases form physically crosslinked networks characterized by non-uniform spatial distribution of high-functionality crosslinks. The swelling of these networks by selective solvents gives rise to novel "mesogels". Three theoretical aspects of these systems, focusing on the lamellar case, are considered: i) The SCF theory of the equilibrium fraction of bridging chains in mesophases formed by a melt of ABA triblock copolymers. ii) The swelling equilibrium and the deformation behavior of mesogels swollen by a selective solvent for …

Elementary Deformations and the HyperKähler-Quaternionic Kähler Correspondence

2014

The hyperKahler-quaternionic Kahler correspondence constructs quaternionic Kahler metrics from hyperKahler metrics with a rotating circle symmetry. We discuss how this may be interpreted as a combination of the twist construction with the concept of elementary deformation, surveying results of our forthcoming paper. We outline how this leads to a uniqueness statement for the above correspondence and indicate how basic examples of c-map constructions may be realised in this context.

Linear pseudo-fermions

2012

In a recent series of papers we have analyzed a certain deformation of the canonical commutation relations producing an interesting functional structure which has been proved to have some connections with physics, and in particular with quasi-hermitian quantum mechanics. Here we repeat a similar analysis starting with the canonical anticommutation relations. We will show that in this case most of the assumptions needed in the former situation are automatically satisfied, making our construction rather {\em friendly}. We discuss some examples of our construction, again related to quasi-hermitian quantum mechanics, and the bi-coherent states for the system.

Micro- to macro-scale internal structures, diagenesis and petrophysical evolution of injectite networks in the Vocontian Basin (France): implications…

2015

27 pages; International audience; This study discusses the characteristics of two Lower Cretaceous injectite networks in the Vocontian Basin (SE France) using combined structural, sedimentary, diagenetic, and petrophysical analyses. Internal structures, at both the macro- and micro-scale, and diagenetic phases characterising these injectite networks have been described. Simultaneously, precementation porosity values were estimated and parameters controlling the geographical distributions of these values were analysed and statistically tested. All of the data were integrated so as to reconstruct the spatial evolution of the porosity from the time of injection to modern times through five maj…

Deformation Quantization by Moyal Star-Product and Stratonovich Chaos

2012

We make a deformation quantization by Moyal star-product on a space of functions endowed with the normalized Wick product and where Stratonovich chaos are well defined.

Surface effects, boundary conditions and evolution laws within second strain gradient plasticity

2014

Abstract The principle of the virtual power (PVP) is used in conjunction with the concepts of “energy residual” and “insulation condition” to address second strain gradient plasticity. The energy residual with its typical divergence format is an extra stress power playing the role of basic state variable to describe the gradient effects, whereas the insulation condition constitutes a global energy characterization of the body as part of the body/environment system. The microstructure of a second strain gradient material (but not of a first strain gradient one) is shown to exhibit surface effects with the formation of a thin boundary layer. This boundary layer is in local (and global) equili…

Stress induced grain boundary migration in very soluble brittle salt

1999

Abstract Grain boundary migration (GBM) was studied in-situ at room temperature, atmospheric pressure and an applied diffmfwerential stress of ∼9.5 MPa under the optical microscope, in a wet aggregate of an elastic-brittle salt (sodium chlorate). The aggregate was previously deformed predominantly by a combination of grain boundary sliding, pressure solution and cataclastic solution creep. After deformation, but when the sample was still under differential stress, undeformed, fracture-free grains were observed to grow at the cost of deformed, intensely fractured grains. GMB rates typically fell in the range 2--10 μm/day. GBM took place only as long as the sample was under stress. Boundaries…

Effect of microcracking on pressure-solution strain rate: The Gratz grain-boundary model

1998

Different, but reasonable and well-accepted assumptions made about grain-boundary structure during pressure-solution (PS) creep may easily have an effect of more than 10 orders of magnitude on the calculated PS deformation rate. Understanding of grain-boundary structure during PS creep is therefore extremely important. Experimental evidence is presented in support of a grain-boundary model previously proposed by A. J. Gratz on the basis of observations on naturally deformed rocks. In this model, boundaries are assumed to have a static island-channel network structure. Channels are located where microcracks intersect the boundary. The rate of material transport is governed by thin-film diffu…

<title>Indentation creep and stress relaxation in amorphous As-S-Se and As-S films</title>

2001

The indentation creep in as-deposited and photopolymerized As- S-Se and As-S films has been investigated. The results show pronounced relaxation of mechanical stresses in the films at room temperature. The relationship (sigma) equals B (epsilon) m between the deformation rate and the stress is observed and the values of the deformation rate sensitivity exponent m < 1 are found. The creep rate was found to be dependent on deposition conditions of layers, applied indentation load, structural state of the material and light irradiation during the creep test.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

1980

A phenomenological theory of the Phase Distribution Chromatography (PDC)-separation effect is outlined and a theoretical equation for the measured PDC-calibration curves is given. Assuming a reversible-thermodynamical equilibrium in the polystyrene-PDC-column, only a relatively small part of the measured PDC-calibration curves could be explained: namely those running below their tangents. In order to explain the whole sigmoidal shape of the experimental curves, a theory of steady state in the system sol/gel was developed assuming deformation of the polymer coil near the gel front due to the stress related to the velocity gradient. The resulting dynamical flow-equilibrium differs highly from…