Fiber Length Variation Research Articles

The performance comparison of hybrid WDM/TDM, TDM and WDM PONs with 128 ONUs

Abstract Here, we have simulated different unidirectional passive optical networks (PONs) technologies such as wavelength division multiplexing (WDM), time-division multiplexing (TDM) and hybridPONs with different users for varying fiber length, data rate, continuous wave laser power and number of users. Their performances based on the quality-factor (Q-factor) and bit error rate (BER) using OptiSystem software 7.0 with using an Erbium doped-fiber amplifier (EDFA) were compared. Our model used 16 and 128 users, where the performance of the unidirectional Hybrid WDM/TDM PONs with 4 wavelengths and 128 user systems have better high Q-factor and lower BER, compared to that of 128 user WDM PON and 128 user TDM PON systems.

Anatomical Features and Its Radial Variations among Different Catalpa bungei Clones

Research highlights: Annual wood anatomy (xylem) aids our understanding of mature wood formation and the growth strategies of trees. Background and Objectives: Catalpa bungei is an important native species in China that produces excellent quality wood. Herein, we clarified the effects of the genetic origin and cambial age on the anatomical characteristics of C. bungei wood. Materials and Methods: Six new 13-year-old C. bungei clones: ‘1-1’ (n trees = 3), ‘1-3’ (n trees = 3), ‘2-7’ (n trees = 3), ‘2-8’ (n trees = 3), ‘8-1’ (n trees = 4), and ‘9-1’ (n trees = 3) were removed for study from a plantation in Tianshui City, Gansu province, China. Xylem features were observed and the anatomical variables were manually measured via image analysis on (macro- micro-, and ultra-) features cut from radial increments of earlywood and latewood sampled at breast height. Results: Between the age of 1 and 2 years, wood was diffuse-porous; between the age of 3 and 9 years, wood was semi-ring-porous; and between the age of 10 and 13 years, wood was ring-porous. The effect of clones on anatomical characteristics was significant except for the microfibril angle in latewood and ring width. The transition between juvenile and mature wood was between 7 and 8 years based on patterns of radial variation in fiber length (earlywood) and microfibril angle. From the pith to the bark, fiber length, double wall thickness, fiber wall: lumen ratio, vessel diameter in earlywood, proportion of vessel in earlywood, and axial parenchyma in latewood increased significantly, whereas ring width, earlywood vessels, and the proportion of fiber decreased significantly. In addition, other features, such as vessel length, microfibril angle, and ray proportion, did not differ significantly from the pith to the bark. Conclusions: Breeding program must consider both clone and cambial age to improve the economic profitability of wood production.

Evaluation of Mechanical and Water Absorption Behavior of Natural Fiber-Reinforced Hybrid Biocomposites

ABSTRACT The virtues of hybrid composites are higher performances and improved mechanical properties as compared to polymer composites. Hence, it have been extensively used in various applications. However, only a few works reported on the performance of natural fiber-reinforced biocomposite. In this study, the experimental work has been carried out to investigate the mechanical properties, such as tensile, flexural and impact, of randomly oriented Calotropis gigantea Fiber (CGFs) & Palmyra fiber (PFs)-reinforced Phenol-Formaldehyde (PF) hybrid biocomposites. The samples have been prepared by varying the fiber percentages and fiber length by using hand layup method. The fabricated specimens were tested as per ASTM standard. The results illustrate that the addition of palmyra fiber with Calotropis gigantea fiber composites improved the mechanical properties of hybrid composite. Hybridization of Calotropis gigantea Fiber (CGFs) & Palmyra fiber (PFs) was effective at higher fiber volume percentage composites. Variation in fiber length shows effective results in mechanical properties. The water absorption of the composites increased with the increase in the fiber volume percentage, all the composites attained equilibrium state after 120 hours. To understand the failure mechanism of composites during mechanical testing, the failed specimens were examined using Scanning Electron Microscopic (SEM) images. Also, the failure modes and their effects were discussed.

Characterizing the total within-sample variation in cotton fiber length using the High Volume Instrument fibrogram

Within-sample variation in cotton fiber length is important when explaining variation in yarn quality. However, typical High Volume Instrument (HVI) length parameters, the Upper Half Mean Length (UHML) and Uniformity Index (UI), do not characterize the total within-sample variation in fiber length. HVI fiber length measurements are based on the fibrogram principle where the HVI generates a curve called a fibrogram and reports the UHML and UI. Our results, based on 19,628 commercial bales, reveal that the typical HVI length measurements do not characterize unique types of length variation. Fibrograms from a subset of 538 commercial samples suggest that the fibrograms capture additional within-sample variation in fiber length that is not being currently reported. Two additional sets of samples were then used to evaluate the importance of this additional length variation. Partial Least Square Regression models and leave-one-out cross-validation reveal that the HVI fibrogram explains yarn quality better than current HVI length parameters and is comparable with the Advanced Fiber Information System (AFIS) length distribution by number. The validation results show that the models built with the HVI fibrogram are better than models with the current HVI length parameters and at least as good as the AFIS length distribution by number when predicting yarn quality. Fiber length variation captured by the whole fibrogram could provide a new tool to breeders for selecting breeding lines and spinners for purchasing cotton bales.

Introduction of a Methodology to Enhance the Stabilization Process of PAN Fibers by Modeling and Advanced Characterization.

A methodology for designing the oxidative stabilization process of polyacrylonitrile (PAN) fibers is examined. In its core, this methodology is based on a model that describes the characteristic fiber length variation during thermal processing, through the de-convolution of three main contributors (i.e., entropic and chemical shrinkage and creep elongation). The model demonstrated an additional advantage of offering further insight into the physical and chemical phenomena taking place during the treatment. Validation of PAN-model prediction performance for different processing parameters was achieved as demonstrated by Fourier Transform Infrared Spectroscopy (FTIR) and Differential Scanning Calorimetry (DSC). Τensile testing revealed the effect of processing parameters on fiber quality, while model prediction demonstrated that ladder polymer formation is accelerated at temperatures over 200 °C. Additionally, according the DSC and FTIR measurements predictions from the application of the model during stabilization seem to be more precise at high-temperature stabilization stages. It was shown that mechanical properties could be enhanced preferably by including a treatment step below 200 °C, before the initiation of cyclization reactions. Further confirmation was provided via Raman spectroscopy, which demonstrated that graphitic like planes are formed upon stabilization above 200 °C, and thus multistage stabilization is required to optimize synthesis of carbon fibers. Optical Microscopy proved that isothermal stabilization treatment did not severely alter the cross section geometry of PAN fiber monofilaments.

Relation between muscle architecture and first metacarpal morphology, and its implications for human hand evolution.

Previous studies have proposed that our ability to produce and use stone tools was the primary selective pressure explaining the evolution of the human hand. Derived traits in humans include a robust first metacarpal and longer thumbs relative to the other fingers. Along with other anatomical peculiarities, humans can exert forceful precision and have powerful grips, and can resist loads during tool production and use. Despite this biomechanical explanation for the morphology of the human hand, limited work has been done on the soft tissue and, therefore, the relationship between the hand bones and the muscles most heavily relied upon during tool-related behaviours still requires thorough investigation. For this purpose, we have dissected 23 forearms and hands of fresh human cadavers of known sex and age at death, and dissected all the muscles attached at the first metacarpal (the first dorsal interosseous, opponens pollicis, and abductor pollicis longus muscles). Variations in physiological cross-sectional area, muscle mass, and fibre length were compared with metacarpal anatomy. In no case bone traits were a significant predictor of muscle features. In contrast, sex and age predicted muscle architecture in several cases, thus substantially affecting the functional analysis based on linear measurements of this bone. The data, therefore, failed to provide a deductive framework for predicting muscle recruitment based on measurements of bone from the fossil record.

Stability, variation, and application of AFIS fiber length distributions

BackgroundFiber length is one of the primary quality parameters for the cotton industry when considering the textile performance and end-use quality of cotton. Currently, many decisions regarding cotton fiber length utilize the industry standard measurement device, i.e., the High Volume Instrument (HVI). However, it is documented that complete fiber length distributions hold more information than the currently reported HVI length parameters, i.e., upper half mean length (UHML) and uniformity index (UI). An alternative measurement device, the Advanced Fiber Information System (AFIS), is able to capture additional information about fiber length distribution. What is currently not known is how much additional information the AFIS length distribution holds.ResultsThe stability of differences in within-sample variation in fiber length captured by the AFIS length distribution by number characterizing differences between samples was deemed stable across the extended testing period. A diverse breeding population was evaluated and four significant sources of within sample variation in length were identified. A comparison of the ability between HVI length parameters and AFIS fiber length distribution to correctly categorize breeding lines to their family was performed. In all cases, the AFIS fiber length distribution more accurately identified germplasm families.ConclusionsThe long-term stability test of the AFIS fiber length distribution by number shows that the measurement is stable and can be used to assess differences across samples. However, more information about within-sample variation in fiber length than that can be captured by length parameters is needed to assess differences across samples in many applications. Four length parameters outperform two length parameters when trying to identify the familial background of the samples in this set. These parameters characterize distributional shape differences that are not captured by the standard AFIS length parameters, UQL and short fiber content by number (SFCn). These findings suggest that additional types of variation in cotton fiber length are not captured and are therefore not currently used in most cotton breeding programs.

Effects of length and content of natural cellulose fiber on the mechanical behaviors of phenol formaldehyde composites

In this paper the effects of fiber lengths and contents on the mechanical properties of Phenol Formaldehyde (PF) composite reinforced with the Areca Fine Fiber (AFF) and Sisal Fiber (SF) were evaluated. Composites were prepared by hand lay-up technique for varying fiber length (5, 10, and 15 mm) and content (10, 20, 30, 40, and 50 wt%). Mechanical properties such as tensile, flexural and impact, of composite specimen were measured with the content and length of the fibers. The results revealed that the mechanical property values of both the composites increases with the increase in fiber content and length. The highest values of mechanical properties were obtained in the combination of 40 wt% and 10 mm and on the further addition, the mechanical property values were decreased. Therefore, it is observed that the optimum fiber length and content are 49 wt% and 10 mm to obtain best combination of mechanical behaviors with both the composites.

Mechanical Testing of Poly Hydroxy Butyrate Co Valerate and Natural Fiber by Varying Fiber Length

The knowledge of 3D printing material used in 3D printing technique is so abundant. Even though there are many critical issues in practical applications. This paper reports the mechanical properties of Environmental friendly Bio composites. This composite material is intended to be used as a replacement for the current 3D printing material. The composite was prepared in compression molding technique under 150 kg/cm2 pressure. The composite consists of Poly Hydroxy Butyrate co Valerate (PHBV) and Sansevieria Roxburghiana. The tensile strength of the given specimen is found to be increased by the change in the volume fraction of fibers. Initially composite plates composed of both PHBV and Sansevieria Roxburghiana are prepared with different weight percentage of PHBV and different lengths of fiber such as 20mm, 30mm, 40mm and 50mm.

Influence of Fibre Parameters on Mechanical Properties of Sansevieria Cylindrica Polyester Composites

The sansevieria cylindrica polyester composite slabs are made by compression molding technique using virgin fibres for varying fibre length ( 30 mm, 40 mm, 50 mm) and different weight percentage ( 20%wt, 30% wt, 40%wt, 50% wt ) under room curing temperature and their mechanical properties have been studied. The inclusion of sansevieria cylindrica fibre as reinforcement into polyester matrix improves the flexural and tensile strength till a certain weight percentage, then it decreases drastically by further addition of fibre. It is observed that the mechanical properties of the composites increase with increase in fibre length from 30mm to 40 mm and there is decrease in their strengths for fibre length of 50 mm.

Distributed and discrete hydrogen monitoring through optical fiber sensors based on optical frequency domain reflectometry

The potential of discrete and distributed fiber-based sensors exploiting the Rayleigh scattering signature of doped amorphous silica is investigated for the real time monitoring of molecular hydrogen (H2) detection. We showed that the impact of the refractive index changes induced by the H2 diffusion into the silica host matrix can be used to detect and quantify this gas presence through two approaches: first via the related fiber length variation and second through the observed spectral shift. Comparing the obtained results with H2 diffusion calculations, we can estimate the sensor sensitivity thresholds to be ∼1016 nmolecule cm−3 for the distributed measurements (spatial resolution better than 1 mm) and below ∼1019 nmolecule cm−3 for the discrete-one. The presented architecture of the sensor is well adapted to the monitoring of slowly evolving H2 concentrations such as the ones expected in nuclear waste repositories as the time response of the sensor remains limited by the diffusion of the gas within the optical fiber. These threshold values and time responses can be easily improved by optimizing the length, the composition and/or the geometry of the sensing fiber.

Noise reduction and quantification of fiber orientations in greyscale images.

Quantification of the angular orientation distribution of fibrous tissue structures in scientific images benefits from the Fourier image analysis to obtain quantitative information. Measurement uncertainties represent a major challenge and need to be considered by propagating them in order to determine an adaptive anisotropic Fourier filter. Our adaptive filter method (AF) is based on the maximum relative uncertainty δcut of the power spectrum as well as a weighted radial sum with weighting factor α. We use a Monte-Carlo simulation to obtain realistic greyscale images that include defined variations in fiber thickness, length, and angular dispersion as well as variations in noise. From this simulation the best agreement between predefined and derived angular orientation distribution is found for evaluation parameters δcut = 2.1% and α = 1.5. The resulting cumulative orientation distribution was modeled by a sigmoid function to obtain the mean angle and the fiber dispersion. A comparison to a state-of-the-art band-pass method revealed that the AF method is more suitable for the application on greyscale fiber images, since the error of the fiber dispersion significantly decreased from (33.9 ± 26.5)% to (13.2 ± 12.7)%. Both methods were found to accurately quantify the mean fiber orientation with an error of (1.9 ± 1.5)° and (2.3 ± 2.1)° in case of the AF and the band-pass method, respectively. We demonstrate that the AF method is able to accurately quantify the fiber orientation distribution in in vivo second-harmonic generation images of dermal collagen with a mean fiber orientation error of (6.0 ± 4.0)° and a dispersion error of (9.3 ± 12.1)%.

Reinforced concrete mixture using abaca fiber

This research study discusses the reinforcement of concrete mix design using abaca fiber. The process of mixing the abaca fibrous concrete used in this mixing is the dry mixing method. The addition of abaca fiber to concrete mixture was done with abaca fiber composition with fiber variation: 0%; 0.15%; 0.20%; 0,25% and variation of fiber length: 25 mm; 37.5 mm; 50 mm. The specimens of cylindrical material (100mmx200mm) and beam (100mmx100mmx400mm), are tested after the test object reaches the age of 28 days in the Universal Testing Machine (UTM) and are evaluated through the ASTM standard in compressive strength test, splitting tensile strength and flexural strength. The addition of fibers significantly affects the physical properties of the concrete, when the fiber increases the slump value will be smaller so the mixture becomes more difficult to mix. The results obtained by the abaca fiber concrete mixture for the composition (0.15%) and the ideal fiber length (50 mm) by providing an optimum value increase in the compression test of 12.61%, 72.64% tensile test, 98.98% flexural test of the normal concrete mixture.

Stable radio frequency transfer over fiber based on microwave photonic phase shifter.

We demonstrate a radio frequency (RF) phase-stable transmission over fiber based on microwave photonic phase shifter. In the proposed system, both assistant RF signals are applied to drive two arms of a dual-drive Mach-Zehnder modulator (DMZM), respectively. An optical bandpass filter is followed to filter out the first-order sideband of optical modulated signal. Due to the phase independence between two optical sidebands, the phase perturbation caused by fiber-length variations can be compensated automatically via controlling the direct-current bias voltage of the DMZM. We have performed RF transfer in a 155 km single-mode fiber with a frequency instability of 3.05 × 10-17 at 10,000 s averaging time.

Investigation of surface modification and volume content of glass and carbon fibres from fibre reinforced polymer waste for reinforcing concrete

The proportion of composites, mainly glass and carbon fibre-reinforced polymers (FRP) in the material cycle have been increasing for years in many sectors. Landfilling of FRP waste is forbidden and recycling is still an unsolved issue. Aim of this paper is the investigation of a feasible reuse of FRP as reinforcement in concrete as shredded material or as thermally recovered plain carbon fibres.A huge amount of glass fibre polymer waste is generated in the wind energy sector and shows low alkaline resistance which is not directly applicable as a reinforcement in alkaline concrete without any surface protection. Therefore, different surface treatments were conducted: on the one hand the aim is to protect FRP fragments in concrete and on the other hand to improve the adhesion. The results of pull-out tests show that a sanded surface of glass fibre polymers increases the averaged maximum shear strength by 16 %.Investigation of the influence of different volume contents (0.25, 0.5, 1 and 2 Vol.-%) of recycled, pyrolized carbon fibres with a varying fibre length show a maximum flexural strength at 1 Vol.-% in bending tests on fibre reinforced concrete. Compared to plain concrete an increase of +111 % can be observed.

Seasonal variation of wool fibre length in Karagouniko and Chios sheep in relation to meteorological factors

Karagouniko and Chios sheep breeds present a lot of advantages on the implementation of sheep farming in Greece, a country with diverse relief resulting in a microclimatic variety, but nothing is known about the impact of season, as the outcome of important meteorological variables, on the fibre length growth (FLG) of the aforementioned breeds. Thus, the effect of season (Winter, Spring, Summer, Autumn) on the FLG of these breeds (by using analysis of variance) was studied in the Artificial Insemination Center of Karditsa (39021΄18΄΄N, 21054΄19΄΄E), Periphery of Thessaly, Greece, combined with a correlation analysis between FLG of each examined sheep breed and each of the studied meteorological variables, air temperature (AIRT), relative humidity (RH), sunshine (SUNS) and rainfall (R) for a two-year period. It was found that the FLG of Karagouniko sheep was significantly higher than the respective growth of Chios sheep, for each examined season, while the descending order of seasonal FLG for both breeds was Winter>Spring>Autumn>Summer. Fibre length growth of Karagouniko and Chios breeds correlated negatively with AIRT and SUNS and positively with RH, implying a better FLG in cooler, more overcast and wetter time periods. Our study adds new knowledge concerning the effect of season, and particularly, the effect of the aforementioned meteorological variables on the wool growth of two considerable sheep breeds in Greece, Karagouniko and Chios, opening up new horizons for their exploitation.

The Compressive Strength of Post-Fire Concrete Prepared with Bamboo Fiber

The purpose of this research was to identify the compressive strength of the concrete post-fire with the addition of bamboo fiber length variation. This research used quantitative experimental method. The independent variables were bamboo fiber length variation (2 cm, 3 cm and 4 cm by 1.5% proportion of cement weight, and the combustion temperature variation (200 °C, 300 °C and 400 °C). The dependent variable was compressive strength of concrete. The result showed that the addition of bamboo fiber length variation and combustion temperature variation producing the maximum unit of concrete compressive strength was found in bamboo fiber with length of 2 cm and burned at 200 °C. The value decreased with the increase of combustion temperature. The length of 4 cm bamboo fiber produced the highest compressive strength with the maximum compressive strength 20.93 MPa.

Effect of fiber length on the tensile strength of unidirectionally arrayed chopped strands

This study investigates the effect of fiber length on the tensile strength for discontinuous fiber composites. A composite with a staggered structure of fiber bundles were prepared by stacking prepreg sheets with unidirectionally arrayed chopped strands with a predetermined fiber length. The sheets were prepared by introducing fine slits at regular intervals along the fiber direction. The final failure is caused by an unstable growth of delamination from the tip of the bundles. The conventional linear fracture mechanics model cannot explain the reduction in the tensile strength as the fiber length shortens. Consequently, this paper proposes a novel fracture mechanics model that considers a non-linear stress–strain relation for the composite, which incorporates varying fiber length. The results confirm that this model can explain the relation between the tensile strength and fiber length very well, without any fitting parameters.

Evaluation of Chirped Fiber Bragg Grating with APD on Designed Optical Fiber Communication Link

Abstract Application of fiber Bragg grating (FBG) in optical communication is an evolving field. In this research paper, various types of chirped FBG’s (CFBG) have been used with avalanche photodiode (APD) on the designed optical fiber communication (OFC) link. Data rate of 20 Gbps and return-to-zero modulation format has been kept as fixed parameters. The designed link has been evaluated for varying fiber lengths (100, 200, 300, 400 and 500 km), various type of CFBG’s (linear, quadratic, square root and cubic root) with Gaussian apodization function, varying grating lengths (10, 20, 30, 40 and 50 mm) and operating temperatures (5°C, 10°C, 15°C, 20°C, 25°C, 30°C). The designed OFC link has also been evaluated for APD with and without CFBG. The performance evaluation matrix parameters selected are Q-factor, bit error rate and eye diagram. The OFC link employing CFBG with APD has been found to be superior. In compensating chromatic dispersion, optimum results have been observed for linear CFBG with Gaussian apodization function in comparison to other types of CFBG with 50 mm grating length for the maximum transmission distance.

Comparative Analysis of Soaking Time on Hardness and Tensile Strength for Mercerization Treated Raffia Palm Fibre

The paper aims to study the soaking time on hardness and tensile strength for mercerization modified raffia palm fibre, which will be gathered, extracted, retted, processed and treated with 5% and 10% NaOH concentration using a soaking time of 60(1hr), 120(2hrs), 180(3hrs) and 240 minutes(4hrs) at a varying fibre length of 50, 60, 70 and 80mm. From the experiment conducted for hardness, the maximum optimum value of 395 HB was recorded at 60mm fibre length for 2 hours using 10% NaOH concentration. While the strength gave an average optimum value of 768Mpa at 70mm fibre length for 3 hours using 5% NaOH concentration at varying the soaking time for mercerization modified fibre. The fibre was grounded into smaller particles size and reinforced with high-density polyethylene (HDPE). Different test samples for the production of oil and gas facilities like pipes and pipe joints, a storage system (pressure vessel), etc. and also for producing interior paneling for aircraft and automobiles, household tables and chairs, window frames, laptop cases, and another consumer item. Keywords : Raffia Palm, Soaking Time, Mercerization, high-density polyethylene DOI : 10.7176/ISDE/10-6-02 Publication date :July 31st 2019