Showing papers on "Fiber published in 1973"

Prosthetic device having a porous fiber metal structure

Abstract: Prosthetic devices for replacement, attachment and reconstruction of bone structure in the skeletal systems of humans and animals. The prosthetic devices may be a fiber metal structure of sufficient section to support loads adequately or may include a solid load carrying member having a fiber metal structure secured to the surface thereof. The fiber metal structure is sintered and open-pored so that the bone and tissue into which the prosthetic device is implanted will grow into such fiber metal structure. To provide the proper interlock between fibers, the individual fiber strands are prekinked prior to cutting into the desired length. The kink pattern should be substantially sinusoidal. Preferably such kink pattern should have an amplitude (H) to period (W) relationship, H/W of 0.24 or greater.

Research toward optical-fiber transmission systems

Abstract: The fundementals of optical fiber transmission systems including the fiber transmission medium, sources suitable for use as a carrier, modulation and detection techniques, and some system design considerations are reviewed. The advent of low-loss optical fibers brings new dimensions to optical communication prospects. Fibers may soon be used much as wire pairs of coaxial cable are now used in communication systems. Transmission losses as low as 2 dB/km have been achieved. Experimental repeaters for fiber systems with 10-9error rate at about 300-Mb/s pulse rate have been reported. Fiber cabling and splicing are among the problems requiring new ideas in order to make feasible an operable system.

Ballistic Impact of Textile Structures

Abstract: Previous work on transverse impact of single textile fibers is reviewed and extended to model orthogonal weaves in which fiber crossovers are simplified as pin. joints. A dynamic finite-element computer technique previously developed for single fibers is extended to model the woven panel, and this method is shown to produce results which are in sub stantial agreement with experimental observations of ballistic nylon panels. Impact of a woven textile panel is shown to exhibit substantial differences compared to the equivalent impact of a single fiber, primarily in that the propagating strain waves experience pervasive and complex interactions due to the influence of the fiber crossovers. The vast majority of ballistic energy is seen to be deposited in the orthogonal fibers passing through the impact point, while the other fibers are essentially ineffective, which suggests possible improvements in the design of textile structures intended for dynamic impact applications.

Nylon 6 fibers: Changes in structure between moderate and high draw ratios

Abstract: The in-phase modulus and coefficient of diffusion of nylon 6 fibers are analyzed in terms of wide-and small-angle X-ray diffraction data. Both properties are examined in directions parallel and perpendicular to the fiber axis. The anisotropy in diffusion and mechanical coupling between the crystalline and amorphous phase reaches its maximum at relatively low draw ratios of about 2.5 to 3.0X. With increasing draw ratio the anisotropy in these properties decreases monotonically and reaches its minimum value with the fibers of the highest draw ratio (5.35X). The diffusion analysis yields a heretofore undetermined structural parameter, the separation of the microfibrils. The results indicate that increases in draw ratio lead to an increase in the distance between the microfibrils, a decrease in the diameter to length of the crystallite, and a decrease in the diffusion constant of the permeable phase. The longitudinal structure of the microfibril is not affected significantly during this phase of draw...

Production of shaped articles of homogeneous mixtures of silicon carbide and nitride

Abstract: A shaped article such as a fiber comprising a homogeneous mixture of silicon carbide and nitride is produced by pyrolyzing at about 200* to 800*C a silazane to produce a fusible carbosilazane resin, forming the resin into fiber and heating the fiber in an inert atmosphere to about 800 to 2,000*C. The fiber or other shaped article prior to final pyrolysis may be rendered infusible. Various additives may be incorporated into the fusible carbosilazane prior to shaping.

The Influence of Glycosaminoglycans on the Formation of Fibers from Monomeric Tropocollagen in vitro

Abstract: Well-characterized, monomeric, lathyritic tropocollagen and a variety of well-characterized glycosaminoglycan preparations have been used in turbidimetric studies on collagen fiber formation in vitro. The experiments have been performed under physiological ionic conditions and at 37°C. It has been shown by others that the fibrillogenetic process consists of two stages, a nucleation phase and a fiber growth phase. By addition of polysaccharides before and after the nucleation phase it was possible to differentiate between the effects of the polysaccharides on the nucleation and on the fiber-growth, respectively. Chondroitin sulphate, dermatan sulphate, heparan sulphate, heparin and proteoglycans of chondroitin sulphate and dermatan sulphate, which at 4°C form complexes with tropocollagen, in most cases accelerated the fiber formation, when they were added before the nucleation phase. This phenomenon was ascribed to an effect on the nucleation process. When added after the nucleation phase chondroitin sulphate, a heparan sulphate fraction and especially the proteoglycans delayed the fiber formation. This observation was ascribed to an inhibition of fiber growth from the nuclei. Hyaluronic acid, which increases the activity of the tropocollagen molecules by steric exclusion, accelerated both the nucleation and the fiber growth processes. Keratan sulphate, which does not form complexes with collagen, had no or a slightly decelerating effect, either when added before or after the nucleation. It could be demonstrated by light-scattering technique that certain glycosaminoglycans influenced the properties of the collagen fibrils formed during the early fiber formation process. The observation that certain polysaccharides had different effects on collagen fiber formation, when added before or after the nucleation, shows that the state of aggregation (nucleation) of collagen is of prime importance in determining the effects exerted by the polysaccharides. This finding may explain some of the contradictory data in the literature. Chemical and physical heterogeneity of the glycosaminoglycans also influenced their mode of interaction with collagen during fiber formation.

High modulus, high strength carbon fibers produced from mesophase pitch

Abstract: High modulus, high strength carbon fibers, having a highly oriented structure characterized by the presence of carbon crystallites preferentially aligned parallel to the fiber axis, are produced from carbonaceous pitches which have been transformed, in part, to a liquid crystal or so-called "mesophase" state. When heated to graphitizing temperatures, these fibers develop the three-dimensional order characteristic of polycrystalline graphite.

Process for spinning naphthalate polyester fibers

Abstract: A filament, fiber or yarn consisting of a naphthalate polyester containing at least 85 mol % of ethylene-2,6-naphthalate units and having an intrinsic viscosity of 0.45 to 1.0, said filament, fiber or yarn having a diffrection intensity ratio (R) between a bragg refection angle 2θ = 187.7° and 2θ = 15.6°, as determined by the X-ray diffraction method, being in the range of more than 1.73 and up to 5.00. Electrically insulating material can be produced by heat-treating a fabric consisting mainly of the above naphthalate polyester fibers and with a sleeve consisting mainly of the above naphthalate polyester fibers.

Synthetic fibers and pile fabrics made therefrom

Abstract: A cut pile fabric is produced using a grass-like fiber and, optionally, a crimped or crimpable fiber of lower denier than said grass-like fiber plied therewith. The pile fabric made from such fibers has improved aesthetics (e.g., appearance) and mechanical (e.g., frictional) properties, and closely simulates natural turf.

Separable optical fiber connector and the method of manufacturing the same

Abstract: A separable optical fiber connector and method for manufacturing the connector are disclosed. The end portion of a thermoplastic coated optical fiber is inserted into an axial through hole in a terminal member. The through hole includes a first portion of a relatively large diameter equal to the diameter of the thermoplastic-coated optical fiber. The axial through hole tapers down to a narrow-diameter second portion which has a diameter equal to that of the optical fiber without the thermoplastic coating. The fiber is heated to remove the thermoplastic coating from the fiber, and the end of the fiber from which the coating is thus removed is inserted into the narrow-diameter second portion of the through hole. The protruding end of the fiber is then fixed to the end surface of the terminal member and is polished.

Method for forming wet-laid non-woven webs

Abstract: A method of producing textile-like non-woven essentially binderless webs from fiber furnishes at least about 70% of which comprise man made non-fibrillatable low denier fibers having no large area flat surfaces and which are at least about 1/4 inch in length with a length to diameter ratio of between about 400:1 and 700:1. The method includes a wet laying system in which sufficient wetting agent is added to the water used in dispersing the fibers to wet the fibers completely and reduce the surface tension of the water to between about 30-35 dynes. It also includes agitating the dispersion vigorously to create tumbling water surface conditions in which up to, but less than about 4% by volumeof air is entrained in the water in the form of tiny air bubbles to create a water/air emulsion in which the fibers are dispersed without generating any substantial amount of surface foam. A viscosity modifier in the form of a natural or synthetic gum is also added to stabilize the emulsion and help prevent the dispersed fibers from reflocculating.

Method for forming refractory fibers by laser energy

Abstract: Method and apparatus for forming fibers of refractory materials. A melt volume is continuously formed on a feed rod of the material to be fiberized and a fiber drawn therefrom. The melt volume is formed by introducing the feed rod at a predetermined velocity into a heating zone. The fiber diameter is determined by the relative velocities at which the feed rod is moved and the fiber drawn, and by the fractional density of the feed rod material.

Method and apparatus for producing fiber reinforced organic foam

Abstract: Urethane plastic foam reinforced with glass fibers is provided, the glass fibers being combined with the plastic foam material prior to foaming. The foaming of the plastic material is physically controlled and restrained to achieve particular desired physical characteristics of the final product. By restricting the extent of foaming, and by using particular layers of fibers, high fiber concentration and more dense skin areas can be obtained in the foam; the fibers can also be initially distributed in a manner to increase their concentration near the surfaces of the foam body. Apparatus is provided for producing reinforced foam in a continuous manner and a method is also provided for combining the fiber reinforcement and the foamable plastic material in a manner such that the plastic material is disposed between two layers of the fiber reinforcement to assure proper distribution of the fibers in the foam. In a preferred form, the fibers are initially disposed in the foamable material in a manner to lie generally perpendicular to the primary direction of growth or rise of the foamable material so that the fibers are also generally perpendicular to the resulting elongate cells. The fibers also preferably are of particular lengths and diameters and present in optimum concentrations to achieve maximum reinforcement and strength in the final product.

Hollow fiber reverse osmosis systems analysis and design

Abstract: A predictive model of hollow fiber reverse osmosis systems is developed using the equivalent annulus assumption. The fraction of feed recovered Φ depends on five parameters. Optimum values exist for the ratio of the inside to outside fiber radius ri/ro and for the outside fiber radius ro. For dilute systems, a simple closed form expression is obtained for Φ which enables one to determine optimum values easily. The effects of pressure, temperature, flow rate, concentration, viscosity of the feed, system length, membrane rejection parameter, and number of fibers are studied. Countercurrent is superior to concurrent operation.

Microfiber reinforcement of an arthropod cuticle. Laminated composite material in biology.

Abstract: 1. According to its fine structure arthropod cuticle is a laminated composite material. The exoskeleton of a spider is surveyed in an electron microscopical study as to the characteristics of its fiber reinforcement. 2. Five types of fiber arrangement are distinguished, ranging from unidirectional to continuously rotating fiber orientation and with three types combining elements of both of these extreme cases. The unidirectional type is rare and its occurrence confined to the innermost part of the walking leg endocuticle and to parts of articular membranes. Quite contrary a continuous and regular rotation of fiber direction is common. In hard cuticle (exocuticle) this type of reinforcement is found exclusively. 3. Lamellar width, indicating a 180° rotation of the fiber direction, varies within wide limits. Variation is due to varying numbers of fiber layers and the amount of directional change between them (ca. 0.6–24°, type E). 4. The diameter of the chitin/protein microfiber amounts to ca. 35 A. Its length measured up to 1,5 μm in the preparations. A periodicity of ca. 80 A is noted. The precision of fiber alignment within the cuticle is high. 5. In the cuticle of the opisthosoma and the articular membranes endocuticular lamellae are taking a wavy course, which is interpreted to be in relation to the cuticle's softness. 6. The mechanical implications of both an increasing number of fiber directions in a composite material and of the different types of fiber reinforcement found in the spider cuticle are demonstrated by a calculation of the directional properties of the moduli of elasticity in tension and shear. The predictable strong influence of both the fiber content and the binder material's E-modulus on the mechanical properties of cuticle is illustrated. 7. Instead of a trajectorial design a continuous rotation of the fiber orientation is found in all exocuticles. Thus the spider does not make use of the special advantage (high strength/weight ratio) of unidirectional fiber arrangement in places where it seemed most likely.

Permeable flexible plastic tubing

Abstract: Flexible tubing, particularly suitable for irrigation purposes, consists of a plurality of superposed, elongated, flexible strips, heat sealed along their longitudinal edges and is substantially flat when empty. At least one of said strips is thermoplastic and at least one has a permeable, fibrous structure and is preferably formed from a non-woven fabric such as spun-bonded polyethylene fiber.

Apparatus for producing nonwoven fabric

Abstract: A method of treating a layer of fibers to form a fibrous web having various areas of fiber concentration and opacity. The fiber layer is supported on an impermeable member and moving forces are applied to the supported layer. The forces move the fibers into areas of varying opacity and fiber concentration while maintaining substantially uniform density throughout these areas.

Screw Disclinations in Nematic Samples with Cylindrical Symmetry

Abstract: In order to verify experimentally some recent calculations on screw disclination lines in nematics we have observed with a polarizing microscope, in a meridian section, nematic filled capillary tubes with homeotropic boundary conditions, with or without inserted fibers. In the simple case with no fiber we observe non-singular S = + 1 lines and the point singularities associated with them. The lines of force of the directors are visualized by the flickering of the fluctuations of the molecules and correspond well to the shape predicted theoretically. When a glass fiber (which also imposes a perpendicular orientation on the nematic) is inserted along the cylinder axis, the Frank planar solution is stable above a critical ratio r0/R of the fiber radius to the capillary radius. This instability appears experimentally by slightly displacing the tube. With two fibers, S = − 1 lines are created which appear to have no singular points.

Fiber toration; method, equipment and product

Abstract: Method and apparatus for the production of fibrous materials from attenuable substances, particularly molten glass, are disclosed, along with the fiber products which result. In the disclosed system the material to be fiberized flows into a region established as a result of the interaction of a jet transversely oriented with respect to a larger blast, the material being acted upon in the interaction zone to produce a highly attenuated fiber.

Optical film-fiber coupler

Abstract: There is disclosed an arrangement for coupling guided optical waves from thin-film waveguides to fiber waveguides, and vice versa. The thin film in the former type of guide is provided with an end region which is gradually tapered in thickness along the path of the wave to be guided therein to a cut-off value for the wave. This tapered region of the film causes the wave to propagate out of the film into the lower refractive index substrate of the guide along a small angle with respect to the film-substrate interface. Situated in the substrate slightly below the film-substrate interface is a cavity having a crosssectional shape and cross-sectional dimensions adapted for receiving an end of the fiber waveguide. By properly selecting the orientation and position of the cavity in the substrate, and of the fiber in the cavity, the fiber can be made to intercept the wave coupled out of the film. To insure efficient coupling of the wave into the fiber, the cavity is provided with a hemispherical end shape and is filled with a transparent material having a refractive index exceeding that of the substrate. A hemispherical lens is thereby formed which focuses and directs the wave into the fiber. Efficient coupling of the guided wave from the thin film to the fiber, or from the fiber to the thin film, is thus possible.

Random fiber webs and method of making same

Abstract: Random fiber webs are made from fibers, having different coefficients of heat shrinkage. When the web is subjected to heat the shrinking of the heat-shrinkable fibers causes the lower shrinkage fibers to buckle and loop so that air spaces are created and the bulk and texture of the web is improved. Various types of fibers, natural, synthetic, mineral, etc., may be employed. Also composite synthetic filaments may be used in which the core and sheath have different coefficients of heat shrinkage.

Method for producing nonwoven fabric

Abstract: A method of treating a layer of fibers to form a fibrous web having various areas of fiber concentration and opacity. The fiber layer is supported on an impermeable member and moving forces are applied to the supported layer. The forces move the fibers into areas of varying opacity and fiber concentration while maintaining substantially uniform density throughout these areas.