Showing papers on "Fiber published in 1985"

Effective thermal conductivity of a misoriented short fiber composite

Abstract: This paper examines the effective thermal conductivity of a misoriented short fiber composite The analysis is based on the equivalent inclusion method for steady‐state heat conduction in composite which we have recently proposed The present approach is unique in that it takes into account the interaction among fibers at different orientations Closed form solutions are given for the thermal conductivity of a misoriented short fiber composite Then, numerical results are presented to demonstrate the effects of volume fraction, fiber aspect ratio, and distribution function of fiber orientation on the thermal conductivity

Selective layering of superabsorbents in meltblown substrates

Abstract: The invention generally provides for formation of meltblown material containing wood fiber on to a continuous foraminous belt. During formation a polymer and wood fiber first layer is applied to a moving belt from at least one bank of meltblown forming apparatus. This first layer does not contain superabsorbent. The belt carrying the first layer passes beneath at least one further source of meltblown fiber into which superabsorbent is added along with the wood fibers. This provides at least one additional layer integrally connected to the first-formed layer and having superabsorbent properties. The first layer acts to aid in trapping of any superabsorbent which is not immediately entangled in the meltblown and wood fibers and prevents it passing through the forming belt.

Stress Field in a Coated Continuous Fiber Composite Subjected to Thermo-Mechanical Loadings

Abstract: The stress field in a coated continuous fiber composite subjected to thermo- mechanical loadings is calculated by use of four concentric circular cylinders model. The target material is Ni- or SiC-...

Mercerization of cellulose. II. Alkali–cellulose intermediates and a possible mercerization mechanism

Abstract: Continued study of the five crystalline Na–celluloses, previously shown to occur as intermediates during the mercerization of cellulose and exhibiting two types of crystallographic fiber repeats, further indicates that they fall into three classes based on their unit cells and NaOH contents. In one class are Na–celluloses I and III, both containing up to 34% NaOH; in the second class are Na–celluloses IIA and IIB, marked by ca.15 A fiber repeat and containing up to 65% NaOH; and in the third class is Na–cellulose IV which is likely to be a hydrated form of cellulose II. Na–cellulose I was found to be the common first alkali–cellulose structure produced in the NaOH treatment of both cellulose I and cellulose II. Further study of this conversion step suggested a mercerization mechanism in which the alkali begins the conversion of cellulose to Na–cellulose I in the amorphous parts of the fiber. The conversion of the parallel-chain cellulose I structure to an antiparallel one is likely to occur already in this first step.

Exhaust gas filter

Abstract: An exhaust gas filter for diesel particulates, comprising a row of a plurality of channels of honeycomb structure of porous sintered ceramic fiber composite sheet, the ceramic fiber composite sheet being produced by a paper-forming method from a slurry of alumino-silicate fiber and fire clay. The honeycomb structure of the ceramic fiber composite sheet is formed by stacking plane sheets and corrugated sheets one atop the other. The filter exhibits low pressure drop yet highly efficient operation by having a bulk density of the ceramic fiber composite sheet in the range of 0.1 g/cm3 to 0.8 g/cm3.

BN coating of ceramic fibers for ceramic fiber composites

Abstract: A ceramic fiber composite material comprised of boron nitride coated cera fibers embedded in a ceramic matrix. The boron nitride coating limits both physical bonding and chemical reaction between the fibers and matrix to improve both strength and toughness of the composite material.

Fluid flow sensing apparatus for in vivo and industrial applications employing novel differential optical fiber pressure sensors

Abstract: An optical fiber fluid flow device is provided for in vivo determination of blood flow in arteries. The device includes a fiber optical fluid pressure measuring device having at least first and second optical fiber sensors which optical fiber sensors are positioned in the blood passage and in a restricted flow area in the blood passage and the two fiber optical pressure fluid sensors are connected to an interferometer associated with an opto-electronic demodulator which has an output signal representing the differential pressure between the two sensed area. The device also has utility in industrial applications.

Stimulation of Absorption of Volatile Fatty Acids and Minerals in the Cecum of Rats Adapted to a Very High Fiber Diet

Abstract: The effects of a high fiber diet containing about 50% pectin, gum, crude potato starch and the fiber components of wheat bran and soya seed cake on the cecal absorption of substrates were studied by parallel measurements of cecal arteriovenous differences and blood flows. Rats fed the high fiber diet had heavier cecae and higher cecal wall weight and blood flow than rats fed a fiber-free diet. Very high arteriovenous differences in volatile fatty acids (VFA) were observed and VFA absorption in cecal vein reached 17.5 mumol/min in the high fiber diet group. This process was concomitant to a moderate absorption of Na+ and partly offset by a secretion of Cl-. In contrast, K+, Mg2+ and Ca2+ were absorbed in large amounts along a favorable concentration gradient. About 10% of arterial urea was removed, and there was a substantial reabsorption of ammonia, despite the lower cecal ammonia and the acidic pH in the cecum when the high fiber diet was fed. The present study suggests that rats may tolerate large amounts of diversified fibers or related compounds in the diet. Such a model could contribute to the assessment of the role of VFA in the effect of fiber.

Extensible microfine fiber laminate

Abstract: An extensible water impervious laminated material having an improved hydrostatic head at higher extension is described. A preferred embodiment comprises an inner creped hydrophobic microfine fiber structure sandwiched between and bonded to two reinforcing layers of nonwoven fibers, said microfine fiber structure comprising at least one ply of microfine fibers having a fiber diameter of up to 10 microns. This material is especially useful as an operating room gown.

Electret fiber sheet and method of producing same

Abstract: An electret fiber sheet has polarized charges on its surface and preferably has charges in ordered orientation across it. The polarized charges are present in an amount of at least 7 × 10 -11 C/cm 2 . Such sheets are found to have a high dust collecting efficiency. Sheets having an amount of polarized charge even as high as this are nevertheless stable when they have a maximum activation energy of depolarization of at least 0.2 eV. Such an electret sheet can be obtained by a process comprising placing a fiber sheet between a non-contact type voltage-application electrode and an earth electrode confronting each other and supplying electricity (voltage > 3 kV; current density > 1 x 10 -6 mA/cm 2 ) between the electrodes, provided that the fiber sheet has a weight no more than 80 g/m 2 and a covering factor of at least 60%. The electret fiber sheets are useful in a variety of applications, such as filter materials, especially for collection of micro dust; clothing and furniture apparel for industrial clean rooms; adsorbing materials; and medical materials such as masks and collectors of bacilli.

Composite materials for thermal energy storage

Abstract: The present invention discloses composite material for thermal energy storage based upon polyhydric alcohols, such as pentaerythritol, trimethylol ethane (also known as pentaglycerine), neopentyl glycol and related compounds including trimethylol propane, monoaminopentaerythritol, diamino-pentaerythritol and tris(hydroxymethyl)acetic acid, separately or in combinations, which provide reversible heat storage through crystalline phase transformations. These phase change materials do not become liquid during use and are in contact with at least one material selected from the group consisting of metals, carbon siliceous, plastic, cellulosic, natural fiber, artificial fiber, concrete, gypsum, porous rock, and mixtures thereof. Particulate additions, such as aluminum or graphite powders, as well as metal and carbon fibers can also be incorporated therein. Particulate and/or fibrous additions can be introduced into molten phase change materials which can then be cast into various shapes. After the phase change materials have solidified, the additions will remain dispersed throughout the matrix of the cast solid. The polyol is in contact with at least one material selected from the group consisting of metals, carbon siliceous, plastic, cellulosic, natural fiber, artificial fiber, concrete, gypsum, and mixtures thereof.

Fiber-reinforced syntactic foam composites and method of forming same

Abstract: Fiber-reinforced syntactic foam composites having a low specific gravity and a low coefficient of thermal expansion suitable for forming lightweight structures for spacecraft applications are prepared from a mixture of a heat curable thermosetting resin, hollow microspheres having a diameter of about 5 to 200 micrometers and fibers having a length less than or equal to 250 micrometers.

Pulsed laser damage to optical fibers.

Abstract: This paper describes some observations of pulsed laser damage to optical fibers with emphasis on a damage mode characterized as a linear fracture along the outer core of a fiber. Damage threshold data are presented which illustrate the effects of the focusing lens, end-surface preparation, and type of fiber. An explanation based on fiber-beam misalignment is given and is illustrated by a simple experiment and ray trace.

Microfine fiber laminate

Abstract: A water impervious laminated material is described A preferred embodiment comprises a three-ply hydrophobic microfine fiber structure (20) sandwiched between and fuse bonded to two layers (10, 30) of conjugate fibers having a low melting sheath and a high melting core The inner ply (14) of the hydrophobic microfine fiber structure (20) is relatively high melting while the two outer plies (13, 15) of the hydrophobic microfine fiber structure (20) are low melting The sheaths of the conjugate fibers have been fuse bonded to the hydrophobic microfine fiber structure (20) at a temperature below the melt temperature of the cores of the conjugate fibers so that the cores retain their initial fiber-like integrity

Adenovirus 3 fiber polypeptide gene: implications for the structure of the fiber protein.

Abstract: The nucleotide sequence of a 1,330-base-pair-long DNA segment located between map coordinates 88.5 and 92.3 in the adenovirus type 3 (Ad3) genome was determined. Transcripts from the r-strand of the region were mapped by S1 nuclease analysis and by in vitro translation of RNA, selected by filter hybridization. The results revealed that the sequenced region encodes the Ad3 fiber polypeptide with a molecular weight of 34,800. A comparison between the predicted amino acid sequences of the Ad3 and the Ad2 fiber polypeptides revealed that they have almost identical secondary structures, consisting of a tail, a shaft, and a knob. A striking difference between Ad2 and Ad3 fibers was that the shaft of the Ad3 fiber was significantly shorter, containing only 6 repeat units compared with 22 in the Ad2 fiber. The secondary structure suggests that the fiber is a dimeric structure, as proposed earlier (N.M. Green, N.G. Wrigley, W.C. Russell, S.R. Martin, and A.D. McLachlan, EMBO J. 2:1357-1365, 1983), with the size of the polypeptide determining the length of the fiber protein.

Overview Of Radiation Effects In Fiber Optics

Abstract: The optical properties of fiber waveguides can be degraded by exposure to nuclear radiation, primarily through the generation of color centers in the fiber core. This paper will review recent studies of the radiation-induced absorption in state-of-the-art fiber optics. Particular emphasis is placed on the development of more radiation resistant pure and doped silica core waveguides and on the understanding of the damage processes in these materials. The results of studies of radiation damage in high birefringent, polarization-maintaining fibers and in heavy metal fluoride glasses and fibers will also be reviewed.

Underwater-mateable optical fiber connector.

Abstract: A low-loss, underwater-mateable optical fiber connector which permits connection between a pair of optical fibers (227, and 281) through a fiber-to-fiber butt junction effected by a pair of connector units (201, and 202). Each connector unit houses a fluid-tight interior chamber (208, and 266). A fiber junction contained in one chamber (208) includes an alignment device (277) holding the terminal end of one fiber (281). The other interior chamber (208) contains a fiber guide and transport mechanism (237) which, actuated by the joinder of the connector units, (201, and 202) provides a fluid-resistant, pressure compensated channel between the chambers (208, and 266) and advances the terminal end of the other fiber (281) through the channel to the junction where it is guided into the alignment device (277) to be butt-joined with the one fiber.

Coconut-fiber-reinforced thermosetting plastics

Abstract: Thermosetting plastic composites have been prepared with phenol–formaldehyde resins as well as unsaturated polyesters as binders and coconut hair as fibrous reinforcement Using resole-type phenol–formaldehyde resins, the effect of coconut fiber pretreatment by NaOH, the precondensation time of the impregnated fibrous press material, the resin–fiber ratio, and pressing parameters have been studied Especially advantageous press-material has been obtained using 60–65 wt % linear novolac type phenol-formaldehyde resin as binder and 35–40 wt % of coconut hair Applying unsaturated polyester (UP) as binder, BMC (bulk molding compound)-type press material can be prepared using coconut fiber reinforcement instead of glass fibers To achieve better coupling between coconut fiber and UP matrix, coconut fiber was pretreated by NaOH and/or gamma-preirradiation It has been found that in glass-fiber-reinforced UP press materials a significant part of glass fiber could be changed for short-cut coconut fiber

Thermal conductivity and thermopower of vapor-grown graphite fibers.

Abstract: Values for the thermal conductivity and thermopower of graphite fibers grown by pyrolysis of natural gas are reported between 10 and 370 K. The measurements were made along the fiber axis on both as-grown fibers and fibers heat treated to 3000 \ifmmode^\circ\else\textdegree\fi{}C. It is shown that heat treatment improves the thermal conductivity by a factor of 50: at room temperature highly heat-treated fibers rank among the very best thermal conductors available. We quantitatively interpret our low-temperature thermal conductivity data using the phonon dispersion relation for graphite. Remarkable agreement is achieved between the phonon mean free paths we deduce from our measurements and defect structures we identify in electron micrographs. The thermopower data we report on the highly heat-treated fibers are very similar to those obtained on single-crystal graphite.

Fiber-reinforced materials

Abstract: Fiber-reinforced materials are produced by a process in which a heat-stable thermoplastic aromatic polyether A which contains reactive groups, preferably nitrile groups and/or sulfur bridges and/or arylthio or alkylthio groups, if necessary together with a heat-stable thermoplastic polymer B which does not contain any reactive groups, is applied onto reinforcing fibers, the resulting semi-finished product is molded and, in the molding obtained, the plastic matrix is crosslinked so that the glass transition temperature increases and it becomes virtually insoluble.

Mechanical degradation of glass fibers during compounding with polypropylene

Abstract: The objective was to study the fiber length degradation during compounding of glass fiber with polypropylene. The effect of parameters such as viscosity, total work, concentration on fiber length and dispersion was studied using an automatic particle size analyzer. The length degradation is most severe during the very first stage of the process, i.e., when fiber bundles are being filamentized. The mode of glass fiber incorporation into the melt (fiber addition to the molten resin versus to polypropylene powder prior to compounding) was found to have no effect on the final fiber length. Matrix resin viscosity affects the fiber length significantly. Concentration dependencies of fiber length for different times of compounding suggest that the degradation results from both fiber-fiber and fiber-melt interactions.

Glasses and glass-ceramics from gels

Abstract: The present state and the future of glasses anf glass-ceramics synthesized by the sol-gel method from metal alkoxides have been critically reviewed and discussed. Glasses and glass-ceramics can be prepared in forms of bulk, fiber, sheet, coating film and particulate. Advantages and disadvantages in applying the sol-gel method for each form are discussed. It is shown that this method is very prospective and many materials will be manufactured by this method in the year 2004.

Effect of matrix's type on the dynamic properties for short fiber-elastomer composite

Abstract: The dynamic moduli, E′ and E″, and tan δ for PET–CR, PET–EPDM, and PET–UR composites with unidirectional short fibers were studied as a function of temperature by using a Rheovibron. The temperature dependence of tan δ showed three peaks for PET–elastomer composites. The peaks at the low temperature corresponded to the main dispersion of the respective matrixes and the peak at about 140°C to the α-dispersion of PET fiber. A small and broad peak observed at a temperature between 60 and 120°C may be caused by the relaxation of the interface region between fibers and matrix. The longitudinal storage modulus for the composite E was given by the parallel model as , where E and E are the storage moduli for fiber and matrix and Vf and Vm are the volume fraction of fiber and matrix, respectively. In the transverse direction of fibers, the composite modulus E was expressed by the logarithmic law of mixing as follows: . The peak values of tan δ from the main dispersion of the respective matrixes were given by the equation, (tan δ⊥max)c/(tan δmax)m 1 − β · Vf, where (tan δ⊥max)c and (tan δmax)m are the maximum values of the loss tangent for the composite and matrix, respectively, and β is coefficient depending on matrix's type. The β value of PET–CR composite is the largest one among those of the composites.