Mean Fiber Length Research Articles

Multiple Data Set (MDS) weak-link scaling analysis of jute fibres

Jute technical fibres were tested in tension at 10 different gauge lengths between 6 mm and 300 mm (⩾50 or ⩾100 tests at long or short gauge lengths respectively). The Young’s modulus, strain to failure and ultimate tensile strengths were determined individually and then Weibull distribution parameters were estimated using the maximum likelihood method to quantify the variation. Single Data Set (SDS, standard) and Multiple Data Set (MDS) weak-link scaling (WLS) predictions were assessed using Anderson–Darling Goodness of Fit Numbers (GOFN). The use of MDS predictions provides better correlation with the experimental data than the standard weak-link scaling method. The authors recommend the use of MDS weak-link scaling for this problem with at least two points (but preferably three) with fibre lengths at two extremes (and, if used, the third point near the mean fibre length).

Combining ability for fiber quality parameters and within-boll yield components in intraspecific and interspecific cotton populations

The major problem with the simultaneous improvement of yield with higher fiber quality is the negative association due to the linkage and pleiotropic effects between lint yield components and fiber quality parameters. The objectives of this research were to estimate the general combining ability (GCA) of parents and specific combining abilities (SCA) of hybrids for fiber quality parameters and within-boll yield components, and to determine the association of fiber quality parameters with basic within-boll lint yield components. In this study, eight cotton cultivars and 15 F1 hybrids obtained by crossing five lines and three testers in the line x tester mating system during 2006 were planted in a randomized block design with four replications in 2007. The predominance of non-additive gene action was estimated for all traits except for the upper half mean fiber length (UHM), fiber strength, and seeds per boll, which were controlled by an additive type gene action due to the high GCA variance. Among the parents, 'Askabat-100' and 'Carmen' were the best general combiners for fiber length, strength, and uniformity index (UI). Additionally, 'GW Teks' and 'Sahin-2000' were determined to be good combiners for lint weight per seed (L/S) and spinnable fibers per seed (F/S). The SCA effects showed that the best specific combination was 'Sealand-542' x 'Sahin-2000' and 'TAM 94L-25' x 'SG-125' for lint percentage, L/S, and lint weight unit per seed surface area. The most important fiber quality parameters, UHM, fiber strength, and UI, were negatively associated with the most basic within-boll lint yield components, L/S, and F/S.

Effect of the dehairing dromedary hair process on yield, fibre diameter, fibre length and fibre tenacity

In raw materials of dromedary hair, there are two distinct fibre populations: the fine one is of textile relevance and the coarse one is rather worthless and must be as a rule separated prior to spinning and subsequent processing. The paper reports an investigation into the effects of fibre passage sequence throughout the Shirley Analyser on the efficiency, the mean fibre diameter and the mean fibre length of the dehairing dromedary hair. Also, it presents the effect of dehairing dromedary hair process on the yield samples. The results show that the most important effect on percentage yield, mean fibre diameter and mean fibre length is caused by the first passage throughout the Shirley Analyser. Following these experiments, we determined an optimal number of passages which is 4. So, the paper discusses the effect of opening operation for dromedary fleece before dehairing on the percentage yield and efficiency of dehairing.

No change in total length of white matter fibers in Alzheimer's disease

White matter changes have been reported as part of Alzheimer dementia. To investigate this, the total subcortical myelinated nerve fiber length was estimated in postmortem brains from eight females (age 79–88 years) with severe Alzheimer's disease (AD) and compared with brains from 10 female control subjects (age 74–92 years). A stereological method for estimating myelinated brain fibers includes sampling systematically, randomly from the white matter, and counting fibers in unbiased counting frames using light microscopy at approximately 6000× magnification. The diameter of each counted fiber was measured to obtain the diameter distribution of myelinated fibers in both groups. The mean total myelinated fiber length was 81,554 km in the AD group and 78,896 km in the control group ( P=0.63). All other measured parameters were also unaffected in the AD brains: The mean fiber length density was 248 km/cm 3 in the AD group and 247 km/cm 3 in the control group; the volume of white matter was 329 cm 3 (AD) and 321 cm 3 (control) and the volume density of myelinated fibers to white matter tissue volume was 0.30 in AD group and 0.31 in the control group. This is the first study of subcortical brain white matter fiber length using a stereological method on postmortem brains from AD patients and control subjects.

Development of Extra‐Long Staple Upland Cotton

An objective of U.S. cotton breeding programs is to provide raw material that processes efficiently and produces better textile products without compromising yield. Annual domestic consumption dropped from 10.4 million bales in 1998 to 5.5 million bales in 2007. Exports increased from 4.3 to 16.2 million bales. Increased reliance on export markets will require the United States to compete more effectively in price and quality. The desired minimum upper half mean (UHM) fiber length in international markets is 28 mm, while the traditional U.S. minimum is 27 mm. To compete at this higher UHM length expectation, breeding programs should target minimums well above the international base. Extra‐long staple (ELS) upland cotton (Gossypium hirsutum L.) germplasm lines were developed by the Cotton Improvement Lab, Dep. of Soil and Crop Sciences, Texas A&M AgriLife Research, as part of an effort to create germplasm with combinations of improved fiber quality, especially UHM length and fiber bundle strength. These ELS upland lines exhibit high volume instrument UHM length >32.0 mm, and several strains exceed 34.8 mm, which is the minimum UHM length for pima (G. barbadense L.). These ELS strains range in agronomic performance from less than to equal to that of ‘Fiber Max 832’ (PI 603955). TAM 94L‐25 (PI 631440), or its full sib 94L‐2 (unreleased), is the common parent in these ELS strains and is proposed as the major contributor of favorable allelic combinations for this exceptional UHM length.

Applying Quantile Regression to Analysis of AFIS Cotton Fiber Distribution

Varying fiber length distributions of cotton, Gossypium hirsutum L., impacts its spinning performance. Advanced Fiber Information System (AFIS) facilitates the analysis of the length distribution of individual fibers in cotton. Quantile regression is a variant of standard regression with which conditional quantile values can be calculated by minimizing weighted sums of absolute deviations across the entire distribution. Quantile regression was used to analyze AFIS fiber length distribution among five genotypes of upland cotton grown at the Texas Agricultural Experiment Station Research Farm near College Station, TX during 2001 and 2002. The shape of the distribution of ‘CAMD‐E’, a short‐staple variety, was actually similar to ‘Acala 1517‐99’, a long staple variety with good spinning quality, even though CAMD‐E had consistently lower fiber lengths. ‘FM 832’, and ‘TAM 94L‐25’ had similar mean fiber lengths to Acala 1517‐99, but their distribution shape was less skewed. ‘TTU 202’ had high cross entropy values, but little difference was detected in distribution shape by quantile regression. Year had a significant impact on distribution of fiber lengths, affecting distribution scale and location, which may be due to lower fiber fineness and maturity in 2001. Quantile regression was found to be an effective method for analyzing AFIS fiber length distributions, although further testing with a larger set of genotypes and environments with spinning data is needed.

Effect of fiber length on thermomechanical properties of short carbon fiber reinforced polypropylene composites

Carbon fiber reinforced composites have all the ideal properties, leading to their rapid development and successful use for many applications over the last decade. In this paper, short carbon fiber reinforced polypropylene (SCF/PP) composite were prepared with melt blending and hot-pressing techniques. The thermomechanical properties of this composite were investigated taking into account the combined effect of mean fiber length. Thermal stability of the composite was studied via the thermal gravimetric analysis (TGA) and dynamic mechanical analysis (DMA) was used to measure the damping properties of the composites. Finally it can be shown that an increase in fiber length can enhance the thermal stability of SCF/PP composites and improve the damping properties as well.

Registration of TAM 01E‐22 Upland Cotton Germplasm Line with Improved Fiber Bundle Strength

TAM 01E‐22 upland cotton (Gossypium hirsutum L.) germplasm line (Reg. No. GP‐889, PI 652865) was developed by the Cotton Improvement Laboratory, Department of Soil and Crop Sciences and released in 2007 by Texas AgriLife Research. TAM 01E‐22 exhibits high volume instrument (HVI) Upper Half Mean fiber length and HVI fiber bundle strength exceeding the best medium staple uplands commonly grown by Texas producers for these traits. All other HVI fiber properties are within acceptable ranges and lint yield potential is lower than current cultivars.

Study on the Dyed Cotton Fibers Damage in Spinning Processes and its Effect on the Cotton Mélange Yarn Properties

Grey cotton fibers with a mean fiber length and fineness of 29 mm and 4.2 micronair was pretreated, scoured and dyed. Three ring yarns were spun separately from 100% grey cotton (R.R.Y.), 50% dyed and 50% grey cotton blend (M.R.Y.) and 100% dyed cotton (D.R.Y.). The extent of fiber damage was assessed by measuring the length and the mechanical characteristics of cotton fibers after passing the fibers through the lap machine and the draw frame II. Properties of R.R.Y., M.R.Y. and D.R.Y. samples were examined. In terms of tenacity and elongation at break, grey and dyed cotton fibers, which were selected after being processed by the lap machine and the draw frame II, were very similar. The fiber length by number and weight of grey cotton was longer than that of dyed cotton, while the amount of fiber nep and short fiber content of dyed cotton were more than those of grey cotton. The three yarn samples were the same in terms of elongation at break. The tenacity of R.R.Y. was the highest but the yarn sample was the lowest in terms of coefficients of mass variation (Cv%), imperfection and hairiness in comparison with the M.R.Y. and D.R.Y. samples.

Internal Structure and Mechanical Properties of Glass Fibre Reinforced Pc/Abs Injection Mouldings with Different Fibre Surface Treatments

The microstructure (including the morphology, fibre length, and fibre orientation) of injection moulded glass fibre reinforced polycarbonate (PC)/acrylonitrile-butadiene-styrene (ABS) blend was investigated. Three grades of commercially available surface treated glass fibres were used; each grade received a treatment that was specially formulated and optimized to enhance the affinity of the glass fibre surface to PC, ABS or both PC and ABS phases. Morphological evaluation confirms that the glass fibres had a preferential affinity to a particular resin depending on the type of surface treatment applied. This preferential affinity could also be detected through the difference in fibre length distribution in the specimens, although their mean fibre lengths and fibre orientations were quite similar. Flexural modulus, flexural strength and impact strength were all affected by differences in the distribution of fibre lengths. It was also discovered that the resin flowed faster than the glass fibres, especially at the core of the mouldings.

Chronic Inhalation of Short Asbestos: Lung Fiber Burdens and Histopathology for Monkeys Maintained for 11.5 Years after Exposure

In an earlier report, presented the results of an 18-month inhalation exposure of rats and monkeys to short chrysotile asbestos. The mean chamber exposure level was 1.0 mg/m3with an average of 0.79 fibers/ml > 5 μ m in length. Gross and histopathological examination of exposed and control rats indicated no treatment-related lesions. Asbestos bodies adjacent to the terminal bronchioles, but no fibrosis, were found in lung biopsy tissue taken from the exposed monkeys at 10 months post-exposure. Fifteen monkeys (9 exposed and 6 controls) from this study were maintained for 11.5 years following exposure. Lung fiber burdens were determined by transmission electron microscopy. The mean lung burden (± standard deviation) for 59 samples from exposed monkeys was 63 ± 30× 106 fibers/g dry lung (range, 18–139 × 106). The geometric mean fiber length was 3.5 μ m with 35% of the fibers being > 5 μ m in length. These data indicate some chrysotile fibers are durable in vivo for a significant period of time. Lungs were examined grossly and microscopically. No lesions attributable to the inhalation exposure were noted. Asbestos bodies were seen in the lungs of treated monkeys, primarily in the interstitium near bronchioles or small pulmonary blood vessels (which also may have been near to bronchioles just out of the plane of section).

Myofiber Length and Three-Dimensional Localization of NMJs in Normal and Botulinum Toxin–Treated Adult Extraocular Muscles

The density and three-dimensional localization of neuromuscular junctions (NMJs) of normal and botulinum toxin-treated normal adult rabbit and monkey extraocular muscles (EOMs) were analyzed. To demonstrate average myofiber length, randomly selected individual myofibers were reconstructed and compared with total muscle length. Normal adult rabbit and monkey EOM and normal adult rabbit tibialis anterior were dissected in their entirety, frozen, sectioned longitudinally, and immunostained for NMJ localization. In addition, adult rabbit EOMs were injected with 5 U botulinum toxin, and NMJ density was determined after 2 weeks. NMJ locations for the three groups of EOM were reconstructed, and density of NMJ was determined. Individual myofibers were reconstructed from the orbital and global layers to determine mean fiber length. NMJs were dispersed throughout the entire length of all EOMs examined from adult rabbits and monkeys and were visualized by alpha-bungarotoxin staining and three-dimensional reconstruction of serial sections. In leg muscle, two relatively tight bands of NMJs were seen. Botulinum toxin significantly increased total NMJ density. Mean fiber lengths were 1.9 and 4.83 mm in the orbital and global layers, respectively, approximately 10% and 24% of the total origin-to-insertion muscle lengths. In addition, individual myofibers continuously changed their intrafascicular relationships over their lengths. The density and distribution of NMJs in normal EOMs are more extensive than previously described. Individual myofibers are significantly shorter than the tendon-to-tendon muscle length in both muscle layers. Botulinum toxin results in a doubling of NMJ density. NMJ localization in normal EOMs has ramifications for understanding eye movement control, but it is also important when surgical or pharmacologic intervention is used for the treatment of strabismus, nystagmus, or other eye muscle disorders.

Effects of process conditions on Young's modulus and strength of extrudate in short‐fiber‐reinforced polypropylene

AbstractWe examined the effects of process conditions on Young's modulus and tensile strength of extruded short‐fiber reinforced thermoplastics. With increasing extrusion ratio and decreasing extrusion temperature, the fiber alignment increases, the mean fiber length decreases, and the mechanical properties of the matrix are improved. The orientation parameter, mean fiber length, Young's modulus, and tensile strength of the matrix are described as a function of extrusion ratio and extrusion temperature. The models proposed by Fukuda and Kawata, and Fukuda and Chou are applied to predict Young's modulus and tensile strength of the composites using orientation parameter. By comparing the predicted Young's modulus and tensile strength with experimental results, the validity of the models is examined. The prediction of Young's modulus agreed quit with the experimental results. The tensile strength of composite extruded below the melting point nearly matched that of the neat matrix. There is no the strengthening effect of the fiber since the angle between fracture surface and fiber direction is very small. POLYM. COMPOS. 28:29–35, 2007. © 2007 Society of Plastics Engineers

Effect of fiber length of carbon nanotubes on the absorption of erythropoietin from rat small intestine

Erythropoietin (EPO) loaded carbon nanotubes (CNTs) with surfactant as an absorption enhancer were prepared for the oral delivery of EPO using two types of CNTs, long and short fiber length CNTs, and the effect of CNT fiber length on the absorption efficiency of EPO was studied. After Labrasol, PEG-8 caprylic/capric glycerides, as absorption enhancer was adsorbed into long fiber CNTs of which mean fiber length was 20–80 μm, as a carrier, EPO and casein as protease inhibitor and Explotab (sodium starch glycolate) as a disintegrating agent, were mixed. The resulting solid preparation was administered into the rat jejunum and serum EPO levels were measured by ELISA. The dose of EPO, CNTs, casein and Explotab were 100 IU/kg, 5 mg/kg, 25 mg/kg and 2.5 mg/kg, respectively. Serum EPO level reached to C max, 69.0 ± 3.9 mIU/ml, at 3.5 ± 0.1 h and AUC was 175.7 ± 13.8 mIU h/ml. These values were approximately half of that obtained with short fiber length CNTs of which C max was 143.1 ± 15.2 mIU/ml and AUC was 256.3 ± 9.7 mIU h/ml. When amphoteric surfactant, Lipomin LA, sodium β-alkylaminopropionic acid, was used to accelerate the disaggregation of long fiber length CNTs, C max was 36.0 ± 4.9 and AUC was 96.9 ± 11.9, which showed less bioavailability (BA) of EPO. These results suggest that the short fiber length CNTs deliver more both EPO and absorption enhancer to the absorptive cells of the rat small intestine and the aggregation of CNTs is not the critical factor for the oral delivery of EPO.

Pulmonary Effects and Biopersistence of Deposited Silicon Carbide Whisker After 1-Year Inhalation in Rats

Silicon carbide whisker (SiCW) is a durable asbestos substitute. To clarify the biopersistence, the changes of geometrical configurations of deposited whiskers, and potential carcinogenicity and fibrogenicity, 42 Wistar male rats were exposed to SiCW for 6 h/day, 5 days/wk for 1 yr by inhalation. The mass median aerodynamic diameter (geometric standard deviation, GSD), the geometric mean fiber diameter (GSD), and the geometric mean fiber length (GSD) were 2.4 μ m (2.4), 0.5 μ m (1.5) and 2.8 μ m (2.3), respectively. The daily average exposure concentrations were 2.6 ± 0.4 mg/m3 (98 ± 19 fibers/ml) and the rats were sacrificed at 6 days and 3, 6, and 12 mo after the exposure. The SiCW amount deposited in each rat lung at 6 days after the exposure, determined by an x-ray diffraction method, was 5.3 ± 1.4 mg. The biological half-time (BHT) was 16 mo calculated from the deposited SiCW at 6 days and 3, 6, and 12 mo. The BHT was more prolonged than normal physiological clearance. The diameter of SiCW in the lung at each sacrificed time during 12 mo of clearance after the inhalation did not change. However, as for the length of SiCW in the lung, longer SiCW tended to be retained in the lung as the clearance time increased, especially after 6 mo. The histopathological examination revealed bronchoalveolar hyperplasia (BAH) in 2 rats at 1 yr after the exposure and severe fibrotic changes around aggregated SiCW.

Effect of chopped Si–Al–C fiber addition on the mechanical properties of silicon carbide composite

Silicon carbide (SiC) composites containing 0–50 mass% of chopped Tyranno® Si–Al–C (SA) fiber (mean length: 214 μm (SA(214)), 394 μm (SA(394)), and 706 μm (SA(706)) were fabricated using the hot-pressing technique at 1800 °C for 30 min under a uniaxial pressure of 31 MPa in Ar atmosphere. The maximum flexural strength of the SiC composite was 344 MPa for 30 mass% of SA(706) fiber addition, whilst the maximum fracture toughness was 4.7 MPa m1/2 for 40 mass% of SA(706) fiber addition. Increasing the mean fiber length from 214 to 706 μm decreased the flexural strength from 380 to 281 MPa for 30 mass% of fiber addition, whilst the fracture toughness increased from 3.4 to 4.7 MPa m1/2 for 40 mass% of fiber addition. Through use of a treated SA(706) fiber containing an approximately 100 nm surface layer of carbon, the fracture toughness further increased to 6.0 MPa m1/2 for 40 mass% of fiber addition; this value was more than twice that of the monolithic SiC ceramic and is believed to be the highest so far achieved for this type of SiC/SiC composite containing chopped fibers.

Fractionation of fibrous fraction from steam-exploded rice straw

Fractionation of fibrous fraction from steam-exploded rice straw (SERS) of high moisture content have been studied with respect to the separation degree of fibrous tissue from non-fibrous tissue including epidermal, parenchymatous and vessel tissue using a fluidized bed opposed jet mill. Chemical composition and fiber characteristics, such as fiber size and composed cell proportion were studied for the separated fibrous fraction of SERS. 70.4% high cellulose fibrous fraction with 63.1% fiber cell content and 65.6% cellulose content was produced from the fractionation process. The separation degree of fibrous tissue of the fractionated fibrous fraction was 2.04. The mean fiber length was 0.97 mm, slightly longer than the untreated rice straw. The new method is suitable to produce high fiber tissue content fractions without damaging the raw fibers extensively.

Superfine grinding of steam-exploded rice straw and its enzymatic hydrolysis

The combination of low severity steam explosion and superfine grinding has been studied with respect to side products generation and enzymatic hydrolysis efficiency. Chemical compositions, fiber characteristics and composed cells contents in the superfine ground product and the ground residue particles produced by superfine grinding were also studied. At the determined parameters using FJM-200 fluidized bed opposed jet mill, 78% superfine ground steam-exploded rice straw (SERS) products with the mean fiber length of 60 μm were obtained, the particles yield was 179% higher than that from the native rice straw (RS). Enzymatic hydrolysis, chemical composition, fiber characteristics and composed cells proportion of the superfine ground SERS product and the ground residue all show great differences. The difference in enzymatic hydrolysis and structural properties indicates that superfine grinding is a good way to fractionate SERS into easily bio-converted part and difficultly hydrolysed part.

Multivariate modeling of MDF panel properties in relation to wood fiber characteristics

Abstract Properties of medium density fiberboard (MDF) panels in relation to wood and fiber characteristics were investigated. Laboratory MDF panels were manufactured from raw fiber materials from black spruce [Picea mariana (Mill.) BSP.], three hybrid poplar clones (Populus spp.), two exotic larch (Larix gmelinii and Larix sibirica), and a mix of spruce, pine, and fir wood chips. The panels were evaluated for modulus of rupture (MOR), modulus of elasticity (MOE), internal bond (IB), linear expansion (LE), thickness swelling (TS), and water absorption (WA). These properties were analyzed as response variables. As predictor variables, various wood and fiber characteristics were measured, including wood density, pH, base buffering capacity and fiber coarseness. Multiple linear regression analysis was performed to develop functional relationships between panel properties (response variables) and wood fiber characteristics (predictor variables). Ten dummy variables were created and incorporated into the analysis to examine the effects of wood species or type on MDF panel properties. MOR was negatively related to arithmetic fine percentage. MOE was negatively affected by the percentage of small particles (>200 mesh) and wood pH. IB strength was negatively related to arithmetic fine percentage and fiber pH, but positively related to the percentage of small particles (>200 mesh). Wood density affected LE. TS was negatively affected by arithmetic mean fiber length. Arithmetic mean fiber width had a negative effect on panel WA. The presence of dummy variables in the models for MOE, IB and LE indicates that wood fiber characteristics other than those measured in this study significantly affected these panel properties. The study indicates that the refining process can play a significant role in manipulating MDF panel properties.

Effect of Process Conditions on Young's Modulus and Strength of Extrudate in Short-Fiber-Reinforced Polypropylene

In this study, we examined the effects of process conditions on Young's modulus and tensile strength of extruded short-fiber reinforced thermoplastics. With increasing extrusion ratio and decreasing extrusion temperature, the fiber alignment increases, the mean fiber length decreases and the mechanical properties of the matrix are improved. The orientation parameter, mean fiber length, Young's modulus and tensile strength of the matrix are described as a function of extrusion ratio and extrusion temperature. The models proposed by Fukuda and Kawata, and Fukuda and Chou are applied to predict Young's modulus and tensile strength of the composites using the orientation parameter. By comparing the predicted Young's modulus and tensile strength with experimental results, the validity of the models are examined. The prediction of Young's modulus agreed quite well with the experimental results. The tensile strength of composite extruded below the melting point nearly matched that of the neat matrix. There is no strengthening effect of the fiber since the angle between fracture surface and fiber direction is very small.