Paper material properties

It is a pleasure for us who are friends, colleagues, and collaborators, to offer this contribution to a volume published in honor of Yngve Ohm s bS " birthday. For most of his career, Yngve has been interested in response properties of various systems to various probes, and we offer this contribution in that spirit. The Generalized Oscillator Strength, the subject of this paper, is the materials property that describes the response of a medium to swift particle, and thus, perhaps, an appropriate subject for this volume. Mostly, we are happy to take this opportunity to thank Yngve for his help, inspiration, and friendship over the years. 

These effects, specialized for the geometries and materials properties of the collagen-rich stroma and sclera, have been calculated in a paper by Edwards and Prausnitz [197], They also modeled diffusion across the corneal endothelium assuming that the major path was... 

The penetration of fluids into paper is also a very important material property for many product types. It is influenced by a number of factors, not least of which is the sheet structure and porosity. In... 

The characterization of what can be considered as material properties is part of any routine in the studies of new polymers. Thus, any major research paper on new silicone materials should be accounted for in this section. And that is, unfortunately, impossible. 

Table 4.1 shows some of the parameters and properties of the most common carbon fiber paper materials being produced commercially for use in PEM and DLFCs. Figure 4.3 shows an SEM (scanning electron microscope) picture of a carbon fiber paper without any coating. In the following subsection we will briefly discuss the fabrication process of carbon fibers and carbon fiber papers. 

Compost bags PE o o Paper Material selection depends on desired property profilee.gPE-LD-orPE-HD-like... 

In the present paper, the approach chosen at our institute to study the phenomenon of attrition is briefly presented. In the results section, the link between bulk solids material properties and attrition results is discussed. The findings document the suitability of our approach for identifying material specific attrition mechanisms. 

The development of biomechanical models derived from continuum formulations for transport of water and charged species in porous media has been carried out for various soft tissues [1-3] and implemented using finite element models (FEMs) [4-8], Such models provide quantitative views of the response of these complex structures that is especially useful in the study of orthopedic, vascular, ocular, and soft tissue substitutes developed by tissue engineering. In this paper a formulation and FEM are described that incorporate and extend these works in a very general model that identifies physical material properties and allows transient analyses of both natural and artificial soft tissue structures. 

Two types of contributions to dielectric and piezoelectric properties of ferroelectric ceramics are usually distinguished [6], [9-12], One type is called an intrinsic contribution, and it is due to the distortion of the crystal lattice under an applied electric field or a mechanical stress. The second type is called an extrinsic contribution, and it results from the motion of domain walls or domain switching [8], To provide an understanding of material properties of pzt, several methods to separate the intrinsic and extrinsic contributions were proposed. These methods are indirect, and are based on measurements of the dielectric and piezoelectric properties of ferroelectric ceramics [8], [10-12], In the experiments reported in this paper a different approach is adopted, which is based on measurements of high-resolution synchrotron X-ray powder diffraction. The shift in the positions of the diffraction peaks under applied electric field gives the intrinsic lattice deformation, whereas the domain switching can be calculated from the change in peak intensities [13,14],... 

Attempts to take into account both localization and percolation or, in other words, to allow for quantum effects in percolation go back to Khmel-nitskii s pioneer paper [68]. The experimental attempts to study quantum effects in conductivity close to the percolation threshold have been undertaken in Refs. [69-71]. The physical sense of these results is stated in Ref. [71] and could be described as follows. The percolation cluster is non-uniform it includes both big conductive regions ( lakes ) and small regions (weak links or bottlenecks) which connect lakes to each other. On approaching the percolation threshold from the metallic side of the transition, these weak links become thinner and longer, and at x = xc the cluster breaks or tears into pieces just in such areas. As a result, exactly these conditions start to be sufficient for the electron localization. Thus, a percolation provokes an Anderson localization in bottlenecks of the percolation cluster. Sheng and collaborators [36,37,72] tried to take into account the influence of tunneling on conductivity for systems in the vicinity of the percolation transition. Similar attempts have been made in papers [38,56]. The obtained results prove that the possibility of tunneling shifts the percolation threshold toward smaller x values and affects material properties in its vicinity. 

Charles P. Sturrock and Edwin F. Begley, Computerization and Networking of Materials Databases Fourth Volume, Papers presented at the Fourth International Symposium on the Computerization and Use of Materials Property Data held in Gaithersburg, Maryland, 6-8 October 1993, in ASTM Spec. Tech. Publ., STP 1257, ASTM, Philadelphia, 1995. 

Analysis of these effects is difficult and time consuming. Much recent work has utilized two-dimensional, finite-difference computer codes which require as input extensive material properties, e.g., yield and failure criteria, and constitutive laws. These codes solve the equations of motion for boundary conditions corresponding to given impact geometry and velocities. They have been widely and successfully used to predict the response of metals to high rate impact (2), but extension of this technique to polymeric materials has not been totally successful, partly because of the necessity to incorporate rate effects into the material properties. In this work we examined the strain rate and temperature sensitivity of the yield and fracture behavior of a series of rubber-modified acrylic materials. These materials have commercial and military importance for impact protection since as much as a twofold improvement in high rate impact resistance can be achieved with the proper rubber content. The objective of the study was to develop rate-sensitive yield and failure criteria in a form which could be incorporated into the computer codes. Other material properties (such as the influence of a hydrostatic pressure component on yield and failure and the relaxation spectra necessary to define viscoelastic wave propagation) are necssary before the material description is complete, but these areas will be left for later papers. 

There are two general methods for determining numerical values for [/ , [/ , Va, and U . One is by analysis of actual operating data. Values so obtained are used on geometrically similar systems of a size not too different from the equipment from which the data were obtained. The second method is predictive and is based on the material properties and certain operating parameters. Relative values of the coefficients for the various modes of heat transfer at temperatures up to 980°C (1800°F) are as follows (Holt, Paper 11, Fourth National Heat Transfer Conference, Buffalo, 1960) ... 

In conclusion this paper has tried to focus on some of the analytical techniques which ceui be utilized In the study and correlation of molecular phenomena with material failure. An understanding which Is Important because of the Inherent complexity of the molecular structure of polymers and the effect It has on material properties. 

In Older to calculate the temperature distribution and the thermal stress distribution in the FGM cylinder, effective material properties such as heat expansion coefficient a(r), heat conduct on coefficient k(r), the volume modulus K(r), the shear elasticity G(r) and Young s modi u., E(r) for intermediate composition of the FGM are required. This paper assumes that. ach layer of FGM is simple macroscopicaUy isotropic two-phase system with spherical particles.We utilize formula proposed by K.WakashimaWto calculate effective properties in each layer. 

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