Types Of Fiber Materials Research Articles

Preparation of superhydrophobic and superoleophilic polypropylene fibers with application in oil/water separation

A novel type of fiber material for the separation of oil/water mixed liquids has been prepared by the chemical vapor deposition of hydrophobic silanes on commercially available polypropylene (PP) fiber. To achieve this, the PP fiber materials were first etched by concentrated H2SO4. Then, the as-prepared PP fiber materials were immersed in highly concentrated suspension of graphene oxide modified by amine-functionalized SiO2 nanoparticles (SiO2–GO). Finally, the as-prepared PP fiber materials were treated by the chemical vapor deposition of hydrophobic silane (octyltrichlorosilane) to form a superhydrophobic surface with a water contact angle more than 156o. The hydrophobic lightweight PP fiber materials are almost instantly filled with the oil phase when selectively absorbing oil from water. The oil can also be drained from the absorbed PP fiber materials. Moreover, the PP fiber material shows the good performance for repeated use.

Structural analysis of continuous fiber wound composite impellers of a multistage high-speed counter rotating axial compressor for compressing water vapor (R-718) as refrigerant using Finite Element Analysis

In this study a low cost, light weight and high performance novel filament wound axial impeller of a multistage counter rotating axial compressor for compressing water vapor (R718) as refrigerant is investigated structurally. Three different fiber types were chosen as suitable materials for this study (Kevlar-49, S-Glass & Carbon fiber) with a standard epoxy resin for the composite matrix. Through means of FEA (Finite Element Analysis) method; stress, displacement and vibration analysis procedure is developed to assess the maximum stress, change in dimensions and natural frequencies of these impellers under constant operating conditions. The finite element modeling was performed on commercially available software Abaqus. The modeling technique is explained in detail with regards to static structural and dynamic analysis of the impellers. Operating stresses, maximum shroud deflections, modal frequencies and effect of centrifugal stiffening is calculated and discussed in detail along with Campbell plots for each fiber material type. The study provides critical details about the structural behavior of the impellers and aims to provide a methodology to the compressor designer to support his decision in choosing the type of impeller and designing the housing.

실내장식용 섬유소재의 흡음성에 관한 연구

The purpose of this study is to help to prevent daily noises by measuring the noise absorption coefficient of the non-woven fabrics and wallpapers which are commonly used in lining and noise absorption coefficient of lining curtain. Seven types of fiber materials for the interior decoration, one non-woven fabric for the wallpaper linings, and two types of textiles for curtain linings are used as the experimental materials in this study. The noise absorption coefficient of the noise absorbents were measured by using impedance tube. And the thermal transmittance were measured by using thermal transmittance tester. The results of this study are as follows; Observing the noise absorption efficiency of each experimental materials, the combination of fiber materials and linings, the noise absorption efficiency of cotton, polyester and silk were similar and for the experimental materials of flax, rayon, acrylic and nylon were resulted the similar noise absorption efficiency. The result of combination of fiber material and black fabric was highest among the combined linings. For the combination of fiber material and non-woven fabric, double layers of non-woven fabric resulted slightly higher noise absorption coefficient result than single layer of non-woven fabric. The thermal transmittance and the sound absorbents of experimental materials were affected by the thickness, density and layer of air of the experimental materials.

Frictional Behavior of Plain Woven Fabrics Constructed from Polyester and Cotton Yarns in Different Environmental Conditions

Frictional characteristics of woven fabrics can determine smoothness and softness values of the fabric. Moreover different environmental conditions can leads to change the properties of the weaves. In this paper, we studied the effect of temperature and relative humidity variations on the frictional properties of cotton and polyester fabrics. Plain woven fabrics were produced with polyester warp yarn and two different weft yarns (cotton and polyester). Each fabric was examined in various temperatures and relative humilities; then the frictional forces measurement was carried out on the fabrics in warp over warp direction. The results show that there is a statistically significant difference between the frictional parameters. This difference relates to the type of fiber material (weft yarns), temperature, and relative humidity. In addition, the data reveal that cotton fabrics have more static and kinetic forces than polyester fabrics in all environmental conditions. Moreover, polyester fabrics exposed to a temperature of nearly 45°C and 100% RH, have the maximum smoothness. The highest roughness values for cotton fabrics were under conditions of 45°C and 20% RH.

Nonlinear free vibration of a composite rectangular specially-orthotropic plate with variable fiber spacing

The geometrically nonlinear free vibration of a composite rectangular plate with variable fiber spacing is investigated. The investigation is limited to a single ply composite having straight and parallel fibers. The fibers are distributed more densely in the central region where high stiffness is needed than in other regions. The assumptions of von Karman’s nonlinear thin plate theory are made. The problem is solved numerically using the hierarchical finite element method. The nonlinear equations of free motion are mapped from the time domain to the frequency domain using the harmonic balance method. The resultant nonlinear equations are solved iteratively using the linearized updated mode method. Results for the fundamental linear and nonlinear frequencies are obtained for simply supported and clamped composite square plates with three variable distributions of E-Glass, Graphite, and Boron fibers in Epoxy matrices. The efficiency of the hierarchical finite element procedure is demonstrated through convergence and comparison with published data. The variable fiber spacing, fiber volume fraction, type of fiber material, and boundary conditions are shown to influence the hardening behavior.

Modeling and optimizing the frictional behavior of woven fabrics in climatic conditions using response surface methodology

Frictional characteristics of woven fabrics can determine smoothness and softness values of textiles. In this paper, we have studied the influence of factors such as temperature, relative humidity, fabric structure, type of fiber material, and direction of motion on roughness properties of fabric surface using response surface method (RSM). For this purpose, woven fabrics with plain, rib2/2, twill2/2, twill1/3, twill3/1, twill1/7, and twill7/1 were produced with polyester warp yarn and two different weft yarns (cotton and polyester). Then, a statistical model (RSM) was used for the experimental plan (with these variables) to determine the runs of experiment (or selected points). Next, the frictional forces measurement was carried out on the fabrics in those directions. The experimental results showed that fabric-to-fabric friction (static frictional resistance, kinetic frictional resistance, and smoothness of woven fabrics) is highly sensitive to factors like relative humidity, fabric structure, type of fiber material, and direction of motion while temperature factor (in the range 0–50°C) has no sensitive effect on frictional parameters.

Effective strain of RC beams strengthened in shear with FRP

The failure modes of Reinforced Concrete (RC) beams strengthened in shear with Fiber Reinforced Polymer (FRP) sheets or strips are not well understood as much as those of RC beams reinforced with steel stirrups. When the beams are strengthened in shear with FRP composites, beams may fail due to crushing of the concrete before the FRP reaches its rupture strain. Therefore, the effective strain of the FRP plays an important role in predicting the shear strength of such beams. This paper presents the results of an analytical and experimental study on the performance of reinforced concrete beams strengthened in shear with FRP composites and internally reinforced with conventional steel stirrups. Ten RC beams strengthened with varying FRP reinforcement ratio, the type of fiber material (carbon or glass) and configuration (continuous sheets or strips) were tested. Comparisons between the observed and calculated effective strains of the FRP in the tested beams failing in shear showed reasonable agreement.

FRP로 보강된 철근콘크리트 보의 유효 변형률 예측에 대한 실험적 연구

The shear failure modes of FRP strengthened concrete beams are quite different to those of the beams strengthened with steel stirrups. When the beams are externally wrapped with FRP composites, many beams fail in shear due to concrete crushing before the FRP reaches its rupture strain. In order to predict the shear strength of such beams, the effective strain of the FRP must be blown. This paper presents the results of an experimental study on the performance of reinforced concrete beams externally wrapped with FRP composites and infernally reinforced with steel stirrups. The main parameters of the tests were FRP reinforcement ratio, the type of fiber material (carbon or glass) and configuration (continues sheets or strips). The experimentally observed effective strain of the FRP was compared with the strain calculated using a proposed method.

Utilization of a chemical-mechanical pulp with improved properties from poplar wood in the composition of packing papers

The aim of the present work is to obtain a chemical-mechanical pulp (CMP) from poplar wood with improved properties, to be used in packing papers in place of more expensive softwood or hardwood pulp. For improving the CMP quality indicators, a preliminary treatment of the pulp has been carried out with a mixture of oxidizing enzymes produced from Phanerochaete chrysosporium, including lignin peroxidase, manganese peroxidase, and laccase. The two types of fiber materials obtained were double-stage bleached and then ground to 30oSR. It was found that preliminary enzyme treatment yielded CMP with improved physical, mechanical, and optical properties. The enzyme-pretreated CMP also refined faster, thus reducing the electricity consumption. Bleached CMP from poplar wood, obtained after preliminary enzyme treatment, could be successfully utilized at levels up to 40% in the composition of various packaging papers.

Determining the 3D permeability of fibrous media using the Newton method

This work explores the reliability and sensitivity of using the Newton method to determine the elements of a fiber mat's permeability tensor. The goal of this work is to determine the extent to which experimental errors affect the numerical results and to provide general guidelines on which types of fiber materials are appropriate for this method. The sensitivity analysis reveals that employing the Newton method is a rather robust approach, applicable to a wide range of materials. The sensitivity analysis also reveals robustness with regard to experimental error as well.

Analysis of Variables Influencing the Average-Residual Strength of Fiber-Reinforced Concrete

Abstract The ASTM C 1399, Test Method for Obtaining Average Residual-Strength of Fiber-Reinforced Concrete, became a standard of ASTM International in December 1999. The test method was developed to provide a practical method, both functionally and economically, for evaluating the performance of fiberreinforced concrete (FRC) of any mixture design. The method is a flexure test and the result, the average residual strength (ARS), is a useful parameter in design and quality control testing. The current standard requires a third-point flexural loading-configuration that complies with ASTM C 78, Standard Test Method for Flexural Strength of Concrete (Using Simple Beam With Third-Point Loading), and net-deflection data analysis. Five factors, consisting of loading configuration, deflection measurement, support apparatus, testing machinery and fiber material type are used as test variables in this research in a testing program suited to the application of a statistical analysis of variance procedure, ANOVA, for their affect on ARS. The results of the test program show that no significant effect is found on the value of ARS computed according to ASTM C 1399 for the modified ASTM C 78, MC78, test apparatus when using either gross or net deflection, or when using third-point or centerpoint loading. There is a significant effect on the value of ARS computed according to ASTM C 1399 for the ASTM C 78 test apparatus when comparing the same test variables.

Prospects for use of microbial raw material for fabrication of fibre and film materials. Review

The potential capacity of microorganisms to form fibre structures, fibre- and film-forming polymers, and the monomers for their chemical synthesis was analyzed. The applied aspects of fabrication of oriented polymer materials (fibres and films) from the cellular biomass of fungi, bacteria, individual products of cell metabolism (organic acids, amino acids), and biopolymers (enzymes) were examined. The role of microbial technologies in utilization of the new raw material resources for fabrication of fibres and films, in improving production of existing types of fibres, and in creating new types of fibre materials of natural origin was evaluated.

Method of measuring the strain of fibres in tension with the scanning electron microscope

This study consisted of developing and testing a method for determining the strain of fibre materials in tension. The method is based on a microtensile testing machine, built into a scanning electron microscope, that produces a tensile stress on the fibre. The strain caused by the effecting force is measured from a picture on video tape. The method has been tested with different types of fibre materials. With different fibre glass types the values of elongation at fracture were 0.5–.0%, for Kevlar fibre 1·5–6·0% and for carbon fibre 0.3–0.7%. It was noted that the deformation of glass fibres is not permanent. The method was noted to be practicable for testing different dry fibre materials and the method can be used to measure deformations (from 0·1% to as large deformations as there are). In principle the method is suitable for testing any fibre material, if the fibre properties do not change in vacuum.

Infrared Optical Fibers

A state of the art review of nonsilica based infrared fibers is presented. Two types of fiber materials have been investigated--crystals and glasses. Crystal fiber work appears to be focused on development of short haul CO/sub 2/ laser power delivering lines at 10.6 µm. The maximum delivering power of the CW CO/sub 2/ laser has reached up to about 100 W by the polycrystalline KRS-5 fiber. A number of glass fibers are being developed in fluorides, sulfides and heavy metal oxides. The best optical attenuation of each glass fiber has been respectively reduced to 21 dB/km at 2.55 µm for ZrF/sub 4/-based glass fiber with a core-clad structure, 78 dB/km at 2.4 µm for As-S unclad glass fiber, and 13 dB/km at 2.05 µm (70 dB/km at 2.40 µm) for GeO/sub 2/-Sb/sub 2/O/sub 3/ glass fiber with a core-clad structure. Recent progress of these infrared fibers offers great potential for new wavelength fiber finks operating in the 2-10 µm region which have not been realized by silica-based fiber.

Infrared optical fibers

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Laundering Conditions for Improved Wash-and-Wear Appearance

A method for creasing and measurement of crease recovery angles in water has been developed. Creasing and crease recovery of fabrics of polyester, cotton, blends of polyester/cotton, acrylic, and nylon have been studied under conditions similar to those present in the washing process. The following parameters which influence wash wrinkling have been investigated: degree of swelling at the time of creasing, temperatures and times during creasing and crease recovery. The effects of these factors vary widely with the type of fiber material. The degree of swelling at the time of creasing affects the crease recovery angles of cotton. The temperature level and the duration of creasing and crease recovery are of great importance for polyester and acrylic materials.