In this work, we present the Poroelastic Relaxation Indentation (PRI) testing approach for quantifying the mechanical and transport properties of thin layers of poly(ethylene glycol) hydrogels with thicknesses on the order of 200 mm. Specifically, PRI characterizes poroelastic relaxation in hydrogels by indenting the material at fixed depth and measuring the contact area-dependent load relaxati...

Constitutive equations of cyclic strain and stress softening for materials with low internal stress levels are derived from the rate theory. The study shows that over the high stress and low temperature range where the description of plastic flow in cyclic softening can be approximated with activation over a single energy barrier, cyclic strain softening is well related to stress relaxation pro...

We created a material with a composition gradient within each grain. Due to the graded composition the ceramic does not show a sharp change in dielectric constant near the relaxation frequency. Instead, we observe gradual decrease in dielectric constant with frequency, with the loss tangent remaining practically unchanged (below 0.02 everywhere within the frequency range 0.0003-3 GHz). The tuna...

Charcoals prepared from certain tropical woods contain stable paramagnetic centers, and these have been characterized by EPR spectroscopy in the absence and presence of oxygen. The EPR-detectable spin density has been determined, as has been the temperature- and frequency-dependence of the oxygen broadening of the EPR signal, which is orders of magnitude larger than that observed with other mat...

Resolving the atomic structure of the surface of ice particles within clouds, over the temperature range encountered in the atmosphere and relevant to understanding heterogeneous catalysis on ice, remains an experimental challenge. By using first-principles calculations, we show that the surface of crystalline ice exhibits a remarkable variance in vacancy formation energies, akin to an amorphou...

We computationally investigate cross-property correlations linking fluid permeability to conductive properties in sedimentary rock for a number of pore size parameters based on three-dimensional digitized rock images. In particular, we focus on correlations based on the pore volume-to-surface-area ratio (V(p)/S), a critical channel diameter (c) associated with mercury porosimetry measurements, ...

While tailoring a garment or a technical textile, relaxation processes of a knitted fabric after production have to be taken into account. Such dimensional changes can occur during a long time of dry relaxation, during wet relaxation, or during washing relaxation, the latter having the strongest infl uence on a fabric. Besides fabric construction and yarn material, the dimensions of a knitted f...

The material behavior of ligament is determined by its constituents, their organization and their interaction with each other. To elucidate the origins of the multiaxial material behavior of ligaments, we investigated ligament response to shear loading under both quasi-static and rate-dependent loading conditions. Stress relaxation tests demonstrated that the tissue was highly viscoelastic in s...

Propagons play an important role in tuning the thermal conductivity of nanostructured amorphous materials. Although advances have been made to quantitatively evaluate relaxation time propagons with molecular dynamics, underlying mechanism remains unexplored. Here, we investigate process silicon, silica, and silicon nitride at room temperature terms Akhiezer model, parameters which were evaluate...