Material parameters, determination

The dependences of r on Mw, T and y can all be treated separately, with the exception of polymers of very low Mn where the key material parameters determining the temperature... 

The viscosities of polymer solutions and of polymer melts have some very important common features, which are related to the fundamental nature of the motions of polymer chain segments [4,8,10] resulting in the flow of macromolecular chains. At an empirical level, one manifestation of these interrelationships is that Mcp which is the key material parameter determining the molecular weight dependence of the melt viscosity, can be estimated from the intrinsic viscosity of the polymer under 0 conditions, which was discussed in Chapter 12. If K -Mci.0-5 is expressed in units of cc/grams, then Mcr can be predicted [7] (but only to within a factor of two) by using Equation 13.6. 

Pupeza, J., Wilk, R., and Koch, M. (2007) Highly accurate optical material parameter determination with THz time-domain spectroscopy. Opt. Express, 15, 4335. 

I liis simulation provides the quantitative measures required for evaluation of the extent of deviation from a perfect viscometric flow. Specifically, the finite element model results can be used to calculate the torque corresponding to a given set of experimentally determined material parameters as... 

The interface region in a composite is important in determining the ultimate properties of the composite. At the interface a discontinuity occurs in one or more material parameters such as elastic moduli, thermodynamic parameters such as chemical potential, and the coefficient of thermal expansion. The importance of the interface region in composites stems from two main reasons the interface occupies a large area in composites, and in general, the reinforcement and the matrix form a system that is not in thermodynamic equiUbhum. 

The atoms and molecules at the interface between a Hquid (or soHd) and a vacuum are attracted more strongly toward the interior than toward the vacuum. The material parameter used to characterize this imbalance is the interfacial energy density y, usually called surface tension. It is highest for metals (<1 J/m ) (1 J/m = N/m), moderate for metal oxides (<0.1 J/m ), and lowest for hydrocarbons and fluorocarbons (0.02 J /m minimum) (4). The International Standards Organization describes weU-estabHshed methods for determining surface tension, eg, ISO 304 for Hquids containing surfactants and ISO 6889 for two-Hquid systems containing surfactants. 

Indexings and Lattice Parameter Determination. From a powder pattern of a single component it is possible to determine the indices of many reflections. From this information and the 20-values for the reflections, it is possible to determine the unit cell parameters. As with single crystals this information can then be used to identify the material by searching the NIST Crystal Data File (see "SmaU Molecule Single Stmcture Determination" above). 

In Equation (2) E(0) is the energy gap at 7 = 0, while a and P are materials parameters to be evaluated from experiment. Once the GaAs substrate temperature is measured from the position of Eo(GaAs), the A1 composition of an epilayer can be determined readily from the position of Eq (GaAlAs) at that temperature. 

Physical properties involve tests of the physical index parameters of the materials. For spent foundry sand, these parameters include particle gradation, unit weight, specific density, moisture content, adsorption, hydraulic conductivity, clay content, plastic limit, and plastic index. These parameters determine the suitability of spent foundry sand for uses in potential applications. Typical physical properties of spent green foundry sand are listed in Table 4.5. 

The water-to-silicate molar ratio (R) is an another important technological parameter determining the final form of produced material. For example, fibers can be formed from hydrolysates with R l, for monodisperse spheres R 50 while bulk samples can be obtained from hydrolysates with R ranging broadly from 5 to 15. The hydrolysis process is also strongly influenced by such factors as temperature, time and character of the catalyst used. 

Acrylonitrile is both readily volatile in air (0.13 atm at 23° C) (Mabey et al. 1982) and highly soluble in water (79,000 mg/L) (Klein et al. 1957). These characteristics dominate the behavior of acrylonitrile in the environment. While present in air, acrylonitrile has little tendency to adsorb to particulate matter (Cupitt 1980), so air transport of volatilized material is determined mainly by wind speed and direction. Similarly, acrylonitrile dissolved in water has only a low tendency to adsorb to suspended soils or sediments (Roy and Griffin 1985), so surface transport is determined by water flow parameters. Based on its relatively high water solubility, acrylonitrile is expected to be higly mobile in moist soils. In addition, acrylonitrile may penetrate into groundwater from surface spills or from contaminated surface water. The high vapor pressure indicates that evaporation from dry soil samples is expected to occur rapidly (EPA 1987). 

Use the data below for the erosive wear for alnmina particles impacting on a graphite-fiber-reinforced epoxy resin composite material to determine the four parameters Uf,Us,vi, and Vp in Eq. (P8.1). You may need to look up some additional data and make appropriate assumptions to solve this problem. You may also find a spreadsheet helpful for solving the fom equations with four unknowns. 

Structural analysis of the solid rocket case-grain system using experimentally determined propellant response properties may permit a complete description of the combined stresses and resultant deformations, but a statement expressing the ability of the propellant to withstand these stresses is also required. Such a statement, which relates the physical state at which failure occurs to some material parameters, is called a failure criterion. The criterion for failure permits a prediction of safety margins expected under motor operation and handling and defines the loading regimes where abnormal operations will occur with intolerable frequency. 

Gereg and Capolla developed process parameters determined by a model laboratory bench scale Carver press, model C (Carver Inc. Savannah, Georgia, U.S.A.), which were translated to production scale compactor parameters (6). Their study provided a method to predict whether a material is suitable for roller compaction. Their study objectives were to characterize properties of the material to identify process parameters suitable to achieve the necessary particle size and density using the dry granulation process and then translate laboratory information to a production scale roller compactor. Actually, information developed from a Carver press was correlated and scaled-up to a production scale Fitzpatrick roller compactor. Model IR 520 (Fitzpatrick Co., Elmhurst, Illinois, U.S.A.) The compactor produced very similar powder granule characteristics as the Carver press. Various lactose materials, available as lactose monohydrate or spray dried lactose monohydrate, were used as the model compounds. Results indicated that a parametric correlation could be made between the laboratory bench Carver press and the production scale compactor, and that many process parameters can be transferred directly. 

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