The structure of mitotic chromosomes in cultured newt lung cells was investigated by a quantitative study of their deformability, using micropipettes. Metaphase chromosomes are highly extensible objects that return to their native shape after being stretched up to 10 times their normal length. Larger deformations of 10 to 100 times irreversibly and progressively transform the chromosomes into a...

The stress vs. strain relation of hygroscopic aerogels was tested in a controlled humidity chamber to study how the Young s modulus and non-recoverable strain are affected by the adsorption of water in the gel. Mass gains over desiccated conditions varied from 4% at 32% relative humidity (RH) to 12% at 70% RH. Above 70% RH, the samples failed catastrophically. The Young s modulus increased from...

The main aim of this work was to study the effect of sisal fiber surface treatments on water uptake behavior of composites based on untreated and treated fibers. For this purpose, sisal fibers were treated with different chemical treatments. All surface treatments delayed the water absorption of fibers only for a short time of period. No significant differences were observed in water uptake pro...

We show by atomistic simulations that, in the thermodynamic limit, the in-plane elastic moduli of graphene at finite temperature vanish with system size L as a power law L(-η(u)) with η(u)≃0.325, in agreement with the membrane theory. We provide explicit expressions for the size and strain dependence of graphene's elastic moduli, allowing comparison to experimental data. Our results explain the...

A very simple optical setup for the measurement of the modulus and the phase of the two-point correlation function of a partially coherent light field is presented. The system consists of a slightly modified version of a Young interferometer and requires a single Young mask in order to determine the correlation function at any pairs of points. Experimental results are presented for the case of ...

Short banana fiber reinforced composites have been prepared in laboratory to determine mechanical properties. It has been observed that as soon as the percentage of the banana fiber increases slightly there is a tremendous increase in ultimate tensile strength, % of strain and young modulus of elasticity. Reinforcement of banana fibers in epoxy resin increases stiffness and decreases damping pr...

In this paper, a new model for resonance frequency of clamped circular corrugated diaphragm has been presented. First, an analytical analyzes has been carried out to derive mathematic expressions for mechanical sensitivity of diaphragm with residual stress. Next by using Rayleigh's method we present mathematical model to calculate the resonance frequency of corrugated diaphragm and investigate ...