Acoustical Properties of Mud Sediments
Abstract : Goals include the development of models and methods that explain observed material and acoustic properties of different physical types of shallow-ocean mud sediments. Other goals are to assess prior data relating to the acoustic properties of mud and to provide guidance in the development and interpretation of experiments. A related goal is to construct models that will guide inversion techniques for inferring properties of mud sediments, for estimating accuracy of results, and for use in applications. These goals are science relevant to resolving long-term Naval problems of transmission loss and array response in shallow water over mud sediments and of acoustic detection, localization, and classification of objects buried in mud. Develop analytical fundamental-physics models for geoacoustic properties that show their dependence on mud parameters. Properties include material density, porosity, and compressional and shear sound speeds and attenuations, with focus on depth and frequency dependence. Estimate the accuracy of physical mud parameters that is required for acoustic data comparisons and for making predictions in applications. Use modeling results to provide methodologies for inversion methods in order to determine parameters and profiles in mud sediments.
Role of binding energy (edge-to-face contact of mineral platelets) in the acoustical properties of oceanic mud sediments
A theory for mud sediments presumes a card-house model, where the platelets arrange themselves in a highly porous configuration; electrostatic forces prevent face-to-face contacts. The primary type of contact is where the edge of one platelet touches a face of another. Why such is not also prevented by electrostatic forces is because of van der Waals (vdW) forces between the molecular structures within the two platelets. A quantitative assessment is given of such forces, taking into account the atomic composition and crystalline structure of the platelets, proceeding from the London theory of interaction between non-polar molecules. Double-integration over both platelets leads to a quantitative and simple prediction for the potential energy of vdW interaction as a function of the separation distance, edge-from-face. At moderate nanoscale distances, the resulting force is attractive and is much larger than the electrostatic repulsion force. But, at very close (touching) distances, the intermolecular force ...
Unity Identity Text Self
Abstract Understanding the receptivity of literature, how one work admits many readers, begins with an analogy: unity is to text as identity is to self. Unity here means the way all a text’s features can be related through one central theme. Identity describes a person’s sameness within different behaviors as variations on one identity theme (Lichtenstein). To find unity or identity, however, the interpreter himself plays a behavioral variation on his identity theme. In interpreting, his identity re-creates itself as he shapes the text to match his characteristic defenses, fantasies, and coherences. Thus, what a poet says about fictional, political, or scientific texts expresses the same identity theme as the poems he writes. To understand reading, criticism, and any knowing or making in symbols, then, we need to let go the Cartesian craving for objectivity and accept the themes in ourselves with which we construe the world—including literary works.