Effects of external environments on the short beam shear strength of filament wound graphite/epoxy

Filament wound graphite/epoxy samples were immersed in seawater, deionized water, and toluene at room temperature and 80 deg C for 5, 15, and 43 days, and in methanol at room temperature for 15 and 43 days. The percent weight gains and short beam shear strengths were determined after environmental exposure. Samples immersed in deionized water and seawater had higher percent weight gains than those immersed in toluene at room temperature and 80 deg C. The percent weight gains for samples immersed in methanol at room temperature were comparable to those of deionized water and seawater immersed samples. A comparison of percent decreases in short beam shear strengths could not be made due to a large scatter in data. This may indicate defects in samples due to machining or variations in material properties due to processing

Mixed Reality Architecture: Concept, Construction, Use

Mixed Reality Architecture (MRA) dynamically links and overlays physical and virtual spaces. This paper investigates the topology of and the relationships between the components of MRA. As a phenomenon, MRA takes its place in a long history of technologies that have influenced conditions for social interaction as well as the environment we build around us. However, by providing a flexible spatial topology spanning physical and virtual environments it presents new opportunities for social interaction across electronic media. An experimental MRA is described that allowed us to study some of the emerging issues in this field. It provided material for the development of a framework describing virtual and physical spaces, the links between those and the types of mixed reality structure that we can envisage it being possible to design using these elements. We propose that by re-introducing a level of spatiality into communication across physical and virtual environments MRA will support everyday social interaction, and may convert digital communication media from being socially conservative to a more generative form familiar from physical space

A review of melt and vapor growth techniques for polydiacetylene thin films for nonlinear optical applications

Methods for the growth of polydiacetylene thin films by melt and vapor growth and their subsequent polymerization are summarized. Films with random orientations were obtained when glass or quartz were used as substrates in the vapor growth process. Oriented polydiacetylene films were fabricated by the vapor deposition of diacetylene monomer onto oriented polydiacetylene on a glass substrate and its subsequent polymerization by UV light. A method for the growth of oriented thin films by a melt-shear growth process as well as a method of film growth by seeded recrstallization from the melt between glass plates, that may be applied to the growth of polydiacetylene films, are described. Moreover, a method is presented for the fabrication of single crystal thin films of polyacetylenes by irradiation of the surface of diacetylene single crystals to a depth between 100 and 2000 angstroms

An algorithmic definition of the axial map

The fewest-line axial map, often simply referred to as the 'axial map, is one of the primary tools of space syntax. Its natural language definition has allowed researchers to draw consistent maps that present a concise description of architectural space; it has been established that graph measures obtained from the map are useful for the analysis of pedestrian movement patterns and activities related to such movement: for example, the location of services or of crime. However, the definition has proved difficult to translate into formal language by mathematicians and algorithmic implementers alike. This has meant that space syntax has been criticised for a lack of rigour in the definition of one of its fundamental representations. Here we clarify the original definition of the fewest-line axial map and show that it can be implemented algorithmically. We show that the original definition leads to maps similar to those currently drawn by hand, and we demonstrate that the differences between the two may be accounted for in terms of the detail of the algorithm used. We propose that the analytical power of the axial map in empirical studies derives from the efficient representation of key properties of the spatial configuration that it captures

Process for producing tris s(n-methylamino) methylsilane

A method of producing tris (N-methylamine) methylsilane is described including the steps of forming and cooling a liquid solution of methylamine in an inert solvent and under an inert atmosphere at a temperature of about -30 C and slowly adding a quantity of methyltricholorosilane while maintaining said temperature. The reaction mixture is then heated for about 60 minutes at a temperature of about 40 C, followed by filtering the solid portion from the liquid portion. The liquid is distilled to remove the solvent, resulting in a high yield of tris (N-methylamine) methylsilane

Determination of life for a polyimide-epoxy alternator insulation system

Tests were conducted to predict remaining electrical insulation life of a polyimide epoxy insulated 60 KW, 208 volt homopolar inductor alternator, following completion of 23,130 hours of turbo-alternator endurance tests. The sectioned armature winding of this alternator stator was used as means to evaluate and measure end-life at several aging temperatures for development of an Arrhenius plot. A one-half life rate of 11.3 C was established from these data with a predicted remaining life of 60,000 hours at an armature winding temperature of 248 C and a total life, including endurance test time, of 61,645 hours

A preliminary review of organic materials single crystal growth by the Czochralski technique

The growth of single crystals of organic compounds by the Czochralski method is reviewed. From the literature it is found that single crystals of benzil, a nonlinear optical material with a d sub 11 value of 11.2 + or - 1.5 x d sub 11 value of alpha quartz, has fewer dislocations than generally contained in Bridgman crystals. More perfect crystals were grown by repeated Czochralski growth. This consists of etching away the defect-containing portion of a Czochralski grown crystal and using it as a seed for further growth. Other compounds used to grow single crystals are benzophenone, 12-tricosanone (laurone), and salol. The physical properties, growth apparatus, and processing conditions presented in the literature are discussed. Moreover, some of the possible advantages of growing single crystals of organic compounds in microgravity to obtain more perfect crystals than on Earth are reviewed