Pressure Dependent Volume Change in Some Nanomaterials Using an Equation of State

Volume change versus pressure is expressed through an equation of state (EOS) such as the well-known Mie-Gruneisen equation. Equation of state is an essential requirement to be defined for numerical simulation of high rate events such as impact. All EOSs have some coefficients which are identified by experiment and are usually considered constant and strain rate independent. In this study, the effect of strain rate on the coefficients of Mie-Gruneisen equation is obtained for polyethylene by experiment and numerical simulation. The low and high strain rate compression tests are conducted using Instron testing machine and Hopkinson bar, respectively. The load-displacement and load-volume change curves are obtained from the experiments. The strain rate dependent constants of Mie-Gruneisen equation of state are obtained through a combined experimental/numerical/optimization technique. The compression test is simulated using Ls-dyna hydrocode. The results show that the coefficient γ is not affected by strain rate but the coefficients C and S1 are severely strain rate dependent. The latter varies with strain rate in a linear fashion and the former varies cubically with strain rate.

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Artifacts caused by dehydration and epoxy embedding in TEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010008599x ◽

1991 ◽

Vol 49 ◽

pp. 338-339

Author(s):

Hilton H. Mollenhauer

Keyword(s):

Electron Microscopy ◽

Electron Beam ◽

Volume Change ◽

Tissue Damage ◽

Beam Specimen ◽

Chemical Fixation ◽

Resin Impregnation ◽

Storage Vesicles ◽

A Cell ◽

Tissue Shrinkage

Various means have been devised to preserve biological specimens for electron microscopy, the most common being chemical fixation followed by dehydration and resin impregnation. It is intuitive, and has been amply demonstrated, that these manipulations lead to aberrations of many tissue elements. This report deals with three parts of this problem: specimen dehydration, epoxy embedding resins, and electron beam-specimen interactions. However, because of limited space, only a few points can be summarized.Dehydration: Tissue damage, or at least some molecular transitions within the tissue, must occur during passage of a cell or tissue to a nonaqueous state. Most obvious, perhaps, is a loss of lipid, both that which is in the form of storage vesicles and that associated with tissue elements, particularly membranes. Loss of water during dehydration may also lead to tissue shrinkage of 5-70% (volume change) depending on the tissue and dehydrating agent.

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Short-term volume and turgor regulation in yeast

Essays in Biochemistry ◽

10.1042/bse0450147 ◽

2008 ◽

Vol 45 ◽

pp. 147-160 ◽

Cited By ~ 12

Author(s):

Jörg Schaber ◽

Edda Klipp

Keyword(s):

Dynamic Model ◽

Volume Change ◽

Volume Regulation ◽

Time Course ◽

Osmotic Shock ◽

Intracellular Concentration ◽

Short Term ◽

Hydrodynamic Property ◽

Turgor Regulation ◽

Thermodynamic Framework

Volume is a highly regulated property of cells, because it critically affects intracellular concentration. In the present chapter, we focus on the short-term volume regulation in yeast as a consequence of a shift in extracellular osmotic conditions. We review a basic thermodynamic framework to model volume and solute flows. In addition, we try to select a model for turgor, which is an important hydrodynamic property, especially in walled cells. Finally, we demonstrate the validity of the presented approach by fitting the dynamic model to a time course of volume change upon osmotic shock in yeast.

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