Expansion modulus

Part AM This part lists permitted individual constnic tion materials, apphcable specifications, special requirements, design stress-intensity vafues, and other property information. Of particular importance are the ultrasonic-test and tou ness requirements. Among the properties for which data are included are thermal conduc tivity and diffusivity, coefficient of theiTnal expansion, modulus of elasticity, and yield strength. The design stress-intensity values include a safety factor of 3 on ultimate strength at temperature or 1.5 on yield strength at temperature. 

Figure 20. (a) The (dimensionless) lateral compressibility (dilatational modulus, elastic area expansion modulus) (left ordinate) and the dimensionless area per molecule (right ordinate) as a function of the tail length (t) of the PC lipids in equilibrium bilayer membranes. The conversion to real compressibilities and areas per molecule is discussed in the text, (b) The (dimensionless) surface tension and the (dimensionless) lateral compressibility as a function of the relative expansion for the C PC lipid... 

The effectiveness factor is related to the Thiele modulus for different molar expansion modulus 0 [12]. The molar expansion modulus 0 expresses the intensity of the molar expansion, 0=(m-l),X R. Two simple cases may be considered, whether the cracking reaction is initially controlled by diffusion of reactants in the uncoked catalyst, or not. 

The applications and performance characteristics of waterborne epoxy adhesives can be significantly improved by the incorporation of additives and modifiers into the adhesive formulation. Fillers such as calcium carbonate, talc, and silicas are often used to adjust the viscosity of the liquid adhesive and the thermal expansion, modulus, and strength characteristics of the cured adhesive film. 

Density modulus strength to fracture expansion modulus strength resistance... 

Adhesive Percent of thermai expansion Modulus Glass-transition... 

The membrane deformation is calculated from observed macroscopic changes in cell geometry, usually with the use of simple geometric shapes to approximate the cell shape. The membrane force resultants are calculated from force balance relationships. For example, in the determination of the area expansivity modulus of the red cell membrane or the cortical tension in neutrophils, the force resultants in the plane of the membrane of the red cell or the cortex of the white cell are isotropic. In this case, as long as the membrane surface of the cell does not stick to the pipette, the membrane force resultant can be calculated from the law of Laplace ... 

Using a micropipette and a small suction pressure to aspirate a hemispherical projection from a cell body into the pipette, Evans and Yeung measured a value for the cortical tension of 0.035 mN/m. Needham and Eiochmuth [1992] measured the cortical tension of individual cells that were driven down a tapered pipette in a series of equilibrium positions. In many cases the cortical tension increased as the cell moved further into the pipette, which means that the ceU has an apparent area expansion modulus (Equation 60.7). They obtained an average value of 0.04 mN/m for the expansion modulus and an extrapolated value for the cortical tension (at zero area dilation) in the resting state of 0.024 mN/m. The importance of the actin cytoskeleton in maintaining cortical tension was demonstrated by Tsai et al. [ 1994]. Treatment of the cells with a drug that disrupts actin filament structure (CTB = cytochalasin B) resulted in a decrease in cortical tension from 0.027 to 0.022 mN/m at a CTB concentration of 3 /rM and to 0.014 mN/m at 30 /rM. 

Area expansivity modulus A measure of the resistance of a membrane to area dilation. It is the proportionality between the isotropic force resultant in the membrane and the corresponding fractional change in membrane area. (Units 1 mN/m = 1 dyn/cm)... 

Katnik, C. and Waugh, R. 1990. Alterations of the apparent area expansivity modulus of red blood cell membrane by electric fields. Biophys. J. 57 877-882. 

Recently, semirigid-rod diacrylate compounds were investigated by Hikmet et al. in order to obtain densely crosslinked LC network materials [57] as well as loosely crosslinked anisotropic gel [58-60]. Copolymerization of an LC monoacrylate having a chiral group and LC diacrylate led to a ferroelectric LC network. In a series of papers by Broer et al. [48,49,61,62], highly crosslinked LC networks were prepared by the photopolymerization of diacrylate LC monomers. Photo-polymerization allowed control of the initiation of polymerization and, therefore, the temperature of polymerization. Orientation was induced using surface treatment technique as applied in liquid crystal display, such as a rubbed polyimide film. The resulting ordered networks showed anisotropic behavior in a number of physical properties, such as coefficient of thermal expansion, modulus of elasticity, and refractive index. 

Marsh D (1997) Renormalization of the tension and area expansion modulus in fluid membranes. Biophys J 73 865-869... 

The incorporation of PEO-PPO-PEO (Pluronic L31) surfactants into preformed giant PEE-PEO vesicles has been investigated and was found to be weak and reversible (159). The incorporation reduced the area expansion modulus kx by almost a factor of 2, while dramatically increasing the vesicles susceptibility to lysis. Additionally, water permeability was increased by a factor... 

With respect to membrane bending, four different micropipet experiments have been devised that, together with analyses of thermal fluctuations of vesicle contours, and theoretical predictions [9,27,32,96,97,106,116], have shown that the bending modulus for typical lipid bilayers such as SOPC is around 1 x 10 J. These studies have also shown that cholesterol increases the bending modulus in parallel with its increase in area expansion modulus. 

Figure 9.15 ( ) Water permeability and (O) area expansion modulus versus reduced temperature (f = (T/T, ) 1) of unsaturated lipids at 21°C. Highly unsaturated lipids have low transition temperatures (T ), and thus have higher reduced temperatures.

Coefficient of thermal expansion Coefficient of thermal expansion Modulus of elasticity... 

Thermal stress— dependence on coefficient of thermal expansion, modulus of elasticity, and temperature change... 

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