Fibrous Phase Research Articles

Histogenesis of Dupuytren's disease: An immunohistochemical study of 30 cases

Thirty-seven specimens from the hands of 30 patients with Dupuytren's disease were examined by light microscopy after immunohistochemical staining for the presence of desmin intermediate filaments. Results indicated that desmin-positive cells were present in the proliferative Dupuytren's nodules, and that the number of desmin-positive cells decreased significantly in the fibrous phase of the disease. Also, on the basis of the pattern of distribution of the desmin-positive cells around vessels, we postulate that the desmin-positive cells in Dupuytren's nodules were migrating perivascular smooth muscle cells from the vessel wall. The exact fate of these cells is uncertain, but we hypothesize that these displaced perivascular smooth muscle cells are capable of transforming into collagen-producing, desmin-negative myofibroblasts that form the cellular basis of Dupuytren's lesions.

Novel reinforced polymers based on blends of polystyrene and a thermotropic liquid crystalline polymer

AbstractA thermotropic liquid crystalline polymer (LCP), when added to polystyrene (PS), can function as both a processing aid and a reinforcing filler. Thermal, rheological, and mechanical properties of the pure components and blends containing up to 10 percent LCP are reported. The LCP used is immiscible with PS, and when an extensional component of flow is present during processing, the LCP forms an elongated fibrous phase oriented in the flow direction. This oriented phase lubricates the melt, substantially lowering the viscosity. When the processed blend is cooled, the dispersed fibrous LCP phase is preserved in the solidified material. The LCP microfibers behave like short reinforcing fibers to improve the mechanical properties of the blend; for example, at an LCP concentration of 4.5 percent, the modulus is increased about 40 percent vs. pure PS.

Recent developments in analytic solid modeling

Solid modeling has improved communications among the three major elements of an engineering process: design, analysis and manufacture. Recent developments in analytic solid modeling are reviewed that extend these improvements to conceptual design and to the representation of materials with internal geometry. Vector fields, Boolean operations on sculpted solids and new data links to engineering tomography in the PATRAN system are representative of these developments. Applications are reviewed using new advanced materials that indicate extensions of the current IGES system are needed to define material geometry for solids that include one or more fibrous phases. Working with these materials is a challenge facing an increasing number of designers and analysts in almost all fields of engineering.

Analyse d'une classe de precipites semicoherents fibreux: Cristallographie de l'interface [formula omitted] et champ de deformation

High resolution electron microscopic observations of the interface between V 5Si 3 tetragonal fibrous phase and V 3Si cubic matrix are discussed as regards both structure and elastic strain field. The coherence of the large faces of the fiber, due to the parallelism of (001) V 3Si and (011) V 5Si 3 planes, can be analyzed by means of the C lattice formalism suggested by Bonnet and Durand [ Phil. Mag. 32, 997 (1975)]. The crystallographic orientation and width of the large faces can therefore be related to the orientation relationships between the two phases. The occurrence of a dislocation, the Burgers vector of which ±( l 2 ) [001] V 3Si does not belong to the DSC lattice, at only one of the two tips of each face can also be explained. Such an interphase interface model also predicts a translational dislocation array in each face, which accounts for (i) the singularities due to the microsteps and (ii) the fact that the elastic strain field of the fiber is not strictly the same as that of a dipole of translational dislocations, but rather is that of a dipole of type II Somigliana dislocations, as recently proposed by R.B. An analysis is made of the elastic strain field and of the energy stored by unit length, in both cases of isotropic and anisotropic elasticities. Some numerical applications are given which show strong elastic interaction between the large faces of the fiber.

Microstructure of one of the ternary eutectic alloys in the Bi-In-Sn system

Two ternary eutectic alloys are known to exist in the Bi-In-Sn ternary system. Experiments were conducted to determine the phases present, the structure, and the volume fraction of each phase in one of the two eutectics. The eutectic investigated melted at 332 K and had a composition of 31.6 wt pct Bi, 48.8 wt pct In, and 19.6 wt pct Sn. The phases present are the major phase BiIn2, the β phase of the In-Sn system, and the γ phase of the In-Sn system. The structure consists of the major phase in which are embedded fibers of the two minor phases. The measured volume fractions of the phases are approximately 56 pct BiIn2, 24 pct β, and 20 pct γ. The volume fraction of the two minor phases (44 pct) in the eutectic is well above the percentage of fibrous phase usually found in binary eutectics.

An intergrown perovskite-wollastonite phase in some ferrous blast-furnace slags

During crystallization of silicate liquids, TiO2 tends to form its own mineral. Ferrous blast-furnace slags generally have perovskite as the titanium-rich phase. However, a rounded and fibrous phase, crystallizing instead of perovskite, has been observed in some slag samples: it has an apparently late position in the order of crystallization. Detailed electron microprobe analysis and X-ray diffraction have indicated that this unusual phase is composed of intergrown perovskite and wollastonite. However, wollastonite should not be an equilibrium phase in these slags. Therefore, a series of simple high-temperature furnace experiments were conducted to examine possible origins of this intergrowth. Solid solution, liquid immiscibility, and eutectic growth have all been discounted as possible explanations of the intergrowth. However, blast-furnace slags are non-equilibrium products, and their residual liquids crystallize independently. This intergrown perovskite—wollastonite phase has been accounted for as a product of fractional crystallization within the system CaO-MgO-Al2O3-TiO2-SiO2.

Selective Etching and Laser Melting Studies of Monotectic Composite Structures

Thin slices of directionally solidified, fibrous composite, monotectic alloy samples have been selectively etched to remove the fibrous phase, so to produce fine sieves of filters having pore diameters ≲10μm. Alloys in systems Al-In, Al-Bi and CuAl-Pb have been examined using as etchants aqueous nitric acid (Al-In, Al-Bi) and aqueous citric acid (CuAl-Pb) without applied anode voltages. These alloys and etchants illustrate examples in which fiber and matrix are attacked to different extents (Al-In), the phase interface is selectively attacked (Al-Bi) or only the fibers are attacked (CuAl-Pb). Hole sizes and perfection are compared for etching times, concentrations and anode voltage.Laser melting of the surface of CuAl-Pb samples has been used to screen or frame areas of the composite microstructure and also shows how local melting of the fibrous Pb phase can be used to assess the heat affected zone.

Electron microscopy of fibril-matrix interactions in a natural composite, insect cuticle

The extent and stability of the interactions between the fibrils and the matrix of insect cuticle are shown. Effectively the fibrous phase is a polysaccharide with a very closely attached protein coat. The matrix consists of more loosely bound protein.

New fibrous phase of potassium titanate.

The new phase of potassium titanate was obtained by the water treatment of the blistered solids which were produced by the KDC process of reaction between titanium dioxide and potassium carbonate.The new phase of hydrous potassium titanate is expressed by the empirical formula of 2K2O⋅11TiO2⋅3H2O, and was dehydrated at 110°C and 130°C and decomposed to potassium hexatitanate and potassium oxide at 1100°C. The density of the new phase was measured to be 3.14g/cm3.

Thaumasite in deteriorated soil-cements

Some samples of badly deteriorated soil cement pavement base materials which had been in contact with ground water containing about 2000 ppm SO3 were examined. It appeared that the cause of deterioration was due to formation of thaumasite or possibly of a solid solution between thaumasite and the isostructural phase, ettringite. The deterioration was caused by expansion due to formation of the fibrous phase, apparently the result of prolonged contact of this particular soil-cement with high sulfate content ground water, and possibly affected also by the high dolomite content of the soil.

Wood substance as a water‐reactive fibre‐reinforced composite

SUMMARYA constitutive relation for an elastic fibre composite material consisting of an inert fibrous phase embedded in a water‐reactive matrix has been derived. The relation is determined in terms of the overall stiffness of the composite, the volume proportion of the matrix, and stiffness and sorption functions of the matrix that are dependent on moisture content. The proposed model of the matrix is believed to be appropriate to wood substance. The constitutive relation is, therefore, applicable to a basic element of wood substance and can be applied to models of wood structure to calculate mechanical properties such as shrinkage, moisture‐induced creep and other moisture‐related properties.

Swelling of a fibre reinforced composite in which the matrix is water reactive

The swelling behaviour of an elastic fibre reinforced composite consisting of an inert fibrous phase embedded in a water reactive matrix is described. It is supposed that the addition of water causes the matrix to swell and become more compliant while the fibres passively resist the swelling stresses exerted by the matrix. A concise relation for the shrinkage or swelling strain is derived in terms of moisture content, the volume proportions of the phases, the overall elastic constants of the composite, the elastic constants of the matrix, and the moisture content at which the reinforcing elements are stress free.

Properties of the Group VI B Elements Under Pressure. III. Phase-Diagram Studies of Various Forms of Sulfur

The phase diagram of sulfur has been investigated up to 60 kbar by differential thermal conductivity analysis in piston-cylinder and tetrahedral devices. The data indicate that the melting curve of orthorhombic sulfur rises to a triple point between orthorhombic, fibrous, and liquid sulfur at 37 kbar and 410\ifmmode^\circ\else\textdegree\fi{}C. The solid-solid transformation appears to be irreversible, and the fibrous phase is identical to that produced at high pressure by Geller using annealing techniques. The apparent triple point can be changed to 29 kbar and 380\ifmmode^\circ\else\textdegree\fi{}C by utilizing samples containing an initial nucleation of fibrous sulfur, indicating that the true equilibrium triple point is lower than that determined by ordinary "static" measurements. The pressure dependence of the melting points of fibrous and white (insoluble $\ensuremath{\omega}$) sulfur produced metastably by annealing at high pressure and temperature was also determined. Since melting is found to be reversible above the triple point it is postulated that there exists a transition from the high-viscosity polymerized liquid present between 0.8 and 37 kbar to another liquid form. A possible mechanism for explaining the melting-curve maxima of Group $\mathrm{VI}B$ elements is discussed.

Pressure-Induced Phase of Sulfur-Selenium

Crystals of a fibrous phase of sulfur-selenium obtained at 20 kilobars and 280 degrees C are trigonal, the most probable space groups being P3(1) and P3(2,) with a = 7.85, c = 4.62 +/- 0.01 A. The unit cell contains nine atoms, and the measured density of 3.20 g/cm(3) implies five sulfur and four Se atoms. The structure contains mixed atom helices of 1.54 A pitch and 0.91 A average radius.