Fiber Length Variation Research Articles

A high performance distributed optical fiber sensor based on Φ-OTDR for dynamic strain measurement

A high-performance distributed optical fiber sensor based on phase-sensitive optical time-domain reflectometry (Φ-OTDR) for dynamic strain measurement has been proposed. In this newly designed system, ultraweak fiber Bragg gratings (UWFBGs) are sparsely embedded in the sensing fiber. Through an unbalanced 3 × 3 coupler structure, the reflected lights from two adjacent UWFBGs would be mixed with each other and then split into three parts for phase demodulation. Then, a novelty table-look-up scheme is introduced to precisely demodulate the frequency, amplitude, and phase of dynamic strain. Rayleigh back-scattering light is utilized to identify and locate the accurate position of vibration event between two adjacent UWFBGs. The experimental results show that the proposed system is capable of reconstructing the vibration with a linear intensity response of R 2 = 0.9986 and a fiber length variation sensitivity of 117 pm/(Hz)1/2. Meanwhile, a wide frequency response band from 50 to 2075 Hz is achieved with high signal-to-noise ratio above 56 dB.

Line x Tester (Çoklu Dizi) Yöntemi ile Geliştirilen Bazı Pamuk (Gossypium hirsutum L.) Genotiplerinin Elbistan Koşullarına Uyum Yetenekleri-II; Lif Özellikleri

The aim of cotton cultivation is fiber production with high yield and quality. In this study, parental and hybrids adaptability (GCA and SCA) and gene effects were examined in terms of fiber yield and fiber quality characteristics. The study was carried out in Elbistan plain in 2012 year after the fallowing of hybridization which made in Kahramanmaraş conditions in 2011 year. Elbistan is located at high elevation (about 1100 m-1500 m) from sea level in Turkey and junction of Mediterranean, Central and Eastern Anatolia Regions, which has short period for cotton cultivation . Eight cotton ( Gossypium hirsutum L.) varieties and fifteen F 1 hybrid were used as plant material that obtained by Line x Tester mating design were planted in a randomized block design with four replications. As a result of study, while the maximum fiber yields were determined as 113.3 kgda -1 (1x4, Stoneville 468 x Beli İzvor 432) and 102.83 kgda -1 (Fantom) in Elbistan conditions, and non-additive genes was estimated fiber yield and other fiber properties. The testers supported the fiber fineness , strength and refrectance of fiber while the lines have supported fiber yield and yellowness variations. Furthermore, lines x tester interaction have been supported fiber length, uniformity, elangation and short fiber contents variations. The highest broad-sense heritability determined for fiber yield (H=0.91) and fiber fineness (H=75). Moreover, in this study, while the 1x4 (Stoneville 468 x Beli İzvor 432), 1x5 (Stoneville 468 x Primera) and 3x4 (Furkan x Beli İzvor 432) hybrids showed significant SCA values for fiber yield, micronaire and yellowness, respectively, Stoneville 468 (fiber yield, micronaire and yellowness) Beli İzvor 432 (fiber yield), Berke (fiber strenght), Fantom (fiber fineness) cultivars have showed significant GCA values.

Experimental investigation of multiple Raman peak properties in a hundred-meter tellurite fiber

Multiple Raman peak properties in a 130 m tellurite fiber are demonstrated in this paper. When the tellurite fiber is pumped by a nanosecond laser at ∼1545 nm, a second-order Raman shift with multiple Raman peaks is observed. Especially for the first-order Raman shift, six obvious Raman peaks are observed. When the tellurite fiber is pumped by a picosecond laser at ∼1064 nm, a second-order Raman shift with only dual Raman peaks is obtained. Furthermore, the evolution of Raman shift with the variation of fiber length is investigated.

Processing of PLA/sisal fiber biocomposites using direct- and extrusion-injection molding

ABSTRACTThe processing strategy adopted to develop biocomposites plays a significant role in determining their characteristics. The present experimental investigation explores the feasibility of using direct-injection molding (D-IM) process for processing of sisal fiber (3 mm and 8 mm) reinforced poly-lactic acid biocomposites with a fiber weight fraction of 30%. For a comparative analysis, mechanical and morphological behavior of biocomposites developed using D-IM process is compared with biocomposites developed using extrusion-injection molding (E-IM) process. The mechanical behavior in terms of tensile, flexural and impact properties is compared and discussed in relation to extracted fiber morphology and fiber orientation as well as dispersion within the developed biocomposites. Morphological investigation of extracted fibers revealed severe fiber attrition and fiber length variation during E-IM process as compared with D-IM process. However, short sisal fiber (3 mm) reinforced biocomposites developed using both the processes exhibit uniform fiber dispersion and orientation, resulting in comparable mechanical properties. The tensile and flexural strength of D-IM-SF biocomposites increased remarkably by 34.7% and 15.9%, respectively, as compared with D-IM-LF biocomposites. Similarly, the tensile and flexural modulus of D-IM-SF biocomposites increased significantly by 92.5% and 56.7%, respectively, as compared with D-IM-LF biocomposites. However, D-IM process incorporating long fibers exhibit better impact properties.

Performance Analysis of Digital Modulation for Coherent Detection of OFDM Scheme on Radio over Fiber System

Radio over fiber (RoF) system with the coherent detection offers high linearity for the transparent transport of high-frequency microwave signals, and better receiver sensitivity compared with intensity-modulated direct detection systems. The purpose of this paper is to analyze the performance of digital modulation for coherent detection of orthogonal frequency division multiplexing (OFDM) scheme on RoF system at 10 Gbps up to 100 km fiber length. The results show that coherent detection of OFDM-RoF system with 16 quadrature amplitude modulation (16-QAM) has the value of bit error rate (BER) and the symbol error rate (SER) is very low and its constellation is better compared with other modulation formats (4-QAM, quadrature phase shift keying (QPSK), 8-PSK and 16-PSK), which BER 16-QAM is 0.053 and SER is 15.7%. The results also show that BER value of 4-QAM and QPSK relatively similar to fiber length variations. In general, an increasing value of the BER and SER for each modulation format are almost equal to the fiber length of 60-70 km (Region I and II). However, there is a significant increase in the value of BER in fiber length of 80-100 km (Region III. A and III. B) for the modulation of 4-QAM, QPSK, 8-PSK, and 16-PSK.

Performance Analysis of Digital Modulation for Coherent Detection of OFDM Scheme on Radio over Fiber System

Radio over fiber (RoF) system with the coherent detection offers high linearity for the transparent transport of high-frequency microwave signals, and better receiver sensitivity compared with intensity-modulated direct detection systems. The purpose of this paper is to analyze the performance of digital modulation for coherent detection of orthogonal frequency division multiplexing (OFDM) scheme on RoF system at 10 Gbps up to 100 km fiber length. The results show that coherent detection of OFDM-RoF system with 16 quadrature amplitude modulation (16-QAM) has the value of bit error rate (BER) and the symbol error rate (SER) is very low and its constellation is better compared with other modulation formats (4-QAM, quadrature phase shift keying (QPSK), 8-PSK and 16-PSK), which BER 16-QAM is 0.053 and SER is 15.7%. The results also show that BER value of 4-QAM and QPSK relatively similar to fiber length variations. In general, an increasing value of the BER and SER for each modulation format are almost equal to the fiber length of 60-70 km (Region I and II). However, there is a significant increase in the value of BER in fiber length of 80-100 km (Region III. A and III. B) for the modulation of 4-QAM, QPSK, 8-PSK, and 16-PSK.

PERFORMANCE ANALYSIS OF EDFA BASED ON GAIN WITH DIFFERENT PARAMETERS

The optical fiber amplifier in active medium consist of 10-30(m) length of fiber which is lightly doped with the rare earth element, for example, ytterbium(yb) Erbium(Er). For the long distance optical communication , EDFA is used effectively ,the material which is made by doping silica with erbium. For rising pumping efficiency and amplifier gain Yb is added. Standard EDFA normally operated in the 1530-1565nm region. In this paper the variation of fiber length w.r.t various parameter has been analysis and based on gain and noise figure value is analysis with MATLAB software.

Generation of UWB Doublet Pulse Based on Directly Modulated Laser and Chromatic Dispersion

An ultra-wideband (UWB) doublet pulse generation technique in the optical domain for UWB-over-fiber systems is presented. Our solution is based on the direct modulation of a semiconductor laser, optical filtering, and chromatic dispersion in a transmission fiber. When the integration of the transmitter in optical access network infrastructure is considered, the transmission length difference, or the difference in accumulated dispersion, is an issue to exactly obtain the desired pulse shape. To solve this problem, we propose to adjust the transmitter operation point, specifically the laser chirp, with respect to the targeted transmission fiber length. Bit error rate measurements prove that doublet pulses can be achieved with fiber length variation from 15 to 40 km of single-mode fiber.

Simulative analysis of different modulation formats for RoF Transmission System

AbstractThis paper has represented the operating conditions for radio-over-fiber (RoF) transmission system such as Q factor, received optical power and BER at different fiber lengths. This paper also investigated optical loss, optical power spectrum and electrical power spectrum at different frequencies for different modulation formats and optical loss at different radio frequencies for varying fiber length.

Assessing the wood quality of interior spruce (Picea glauca × P. engelmannii): variation in strength, relative density, microfibril angle, and fiber length

Abstract A dynamic interrelationship exists among wood density and fiber traits (tracheid length and microfibril angel, MFA) and the ultimate wood strength properties. Moreover, many of the basic fundamental wood attributes are heavily influenced by crown size and architecture. In an attempt to examine this interplay, we thoroughly characterized 60 interior spruce (Picea glauca × P. engelmannii) trees sampled in three age classes from four sites in central British Columbia. Breast height discs were taken, and relative wood density was measured along two radii. Tracheid length was assessed on isolated 5 years increments from pith to bark at breast height for each tree, as was MFA. Segmented regression was used to identify the “juvenile to mature wood” transition point, which revealed transition ages of 9.4 and 15.1 years for wood density and MFA, respectively, while fiber length continued to elongate until near 60 years of age. The flexural properties, modulus of elasticity (MoE) and modulus of rupture (MoR), were also quantified in the 60 individuals and found to be best predicted by V FV, a measure of tree vigor, and not the basic wood attributes. These findings imply that long crowns carrying large amounts of foliage, V FV, negatively impact wood strength in interior spruce.

Axial variations in anatomical properties and basic density of Eucalypt urograndis hybrid (Eucalyptus grandis × E. urophylla) clones

We studied two clones of Eucalypturograndis hybrid (Eucalyptus grandis × E. urophylla), GR283 and GR330, grown in Tumkur district of Karnataka (India), and felled 5–6 years old three trees of each clone. We recorded axial variations in heartwood content, bark properties, wood density and anatomical characteristics of wood including fibre length, fibre diameter, fibre wall thickness, lumen diameter, vessel frequency, vessel diameter and vessel element length. Clone GR283 had about 10 % heartwood, significantly lower than for clone GR330 (37 %). Basic wood density along the tree height varied significantly within and between the clones. We observed significant variations in fibre length, fibre diameter and wall thickness within and between the two clones. Vessel frequency and vessel element length did not vary but vessel diameter differed significantly between the clones. With a greater proportion of sapwood, clone GR283 can be utilized for paper and pulp applications. Clone GR330 had a higher proportion of heartwood and lower wood density and, hence, is more suitable for light-weight material applications.

Effect of fibre length and weight percentage on mechanical properties of short sisal/polyester composite

The present study investigates the mechanical properties such as tensile, flexural and impact of randomly oriented short sisal fibre reinforced polyester composites. The composites were fabricated using compression moulding method with varying fibre length (3 mm, 4 mm, 5 mm) and varying weight percentages (20%, 30%, 40%, 50%) of fibre in room temperature. The result from the mechanical tests reveals that the fibre length of 3 mm and fibre weight percentage of 50, sisal fibre reinforced composite offers superior properties compared to other fibre lengths and weighting percentages of sisal fibre.

Empirical statistical model for predicting wood properties of Paulownia fortunie: Part 1: Physical and biometrical properties

This paper describes the development of model to predict the within-tree variation of wood density, shrinkage, fiber length, fiber diameter and cell wall thickness from pith-to-bark and bottom-to-top, using data collected from a 13-year-old paulownia (Paulownia fortunie) stand where trees were planted in an experimental plantation in Iran. The sample disks were taken from each tree to examine the wood density, shrinkage, fiber length, fiber diameter and cell wall thickness variation from pith to bark at 5, 25, 50 and 75% of the total tree height. The study was laid out in a randomized complete block design. Linear prediction model were developed using longitudinal direction (bottom-to-top) and radial direction (pith-to-bark) indices as explanatory variables. The results indicated that, the wood density, shrinkage, fiber length, fiber diameter and cell wall thickness, considerably changes from pith to bark and from the base upwards. Based on the final model, it was found that the physical and biometrical properties were significantly influenced by longitudinal and radial directions. The model equation were based on the model used to describe the within-tree variation in the wood density, shrinkage, fiber length, fiber diameter and cell wall thickness of Paulownia, and is functions of radial and longitudinal directions.

Optimisation of the imaging and dosimetric characteristics of an electronic portal imaging device employing plastic scintillating fibres using Monte Carlo simulations

A Monte Carlo model of a novel electronic portal imaging device (EPID) has been developed using Geant4 and its performance for imaging and dosimetry applications in radiotherapy has been characterised. The EPID geometry is based on a physical prototype under ongoing investigation and comprises an array of plastic scintillating fibres in place of the metal plate/phosphor screen in standard EPIDs. Geometrical and optical transport parameters were varied to investigate their impact on imaging and dosimetry performance. Detection efficiency was most sensitive to variations in fibre length, achieving a peak value of 36% at 50 mm using 400 keV x-rays for the lengths considered. Increases in efficiency for longer fibres were partially offset by reductions in sensitivity. Removing the extra-mural absorber surrounding individual fibres severely decreased the modulation transfer function (MTF), highlighting its importance in maximising spatial resolution. Field size response and relative dose profile simulations demonstrated a water-equivalent dose response and thus the prototype’s suitability for dosimetry applications. Element-to-element mismatch between scintillating fibres and underlying photodiode pixels resulted in a reduced MTF for high spatial frequencies and quasi-periodic variations in dose profile response. This effect is eliminated when fibres are precisely matched to underlying pixels. Simulations strongly suggest that with further optimisation, this prototype EPID may be capable of simultaneous imaging and dosimetry in radiotherapy.

Statistics on the fracture strength of bamboo fibers

Tensile strength is a key mechanical property of fibers used as sustainable reinforcements for advanced fiber‐reinforced composites. This study aims to conduct experimental investigation on the fracture strength of bamboo fibers of different dimensions subjected to longitudinal tensile loading. The statistical distributions of the fracture strength in bamboo fibers are correlated with the effects of fiber length and diameter variation. These are described according to Weibull statistics, which exhibit the random nature of fiber strength. The Weibull function parameters used for strength prediction are obtained from the test specimens. A comparison of predicted results and experimental data is presented to assess the accuracy of using weak‐link scaling. Furthermore, the findings of this study also indicate that fiber strength statistics dominate size dependence of tensile strength. POLYM. COMPOS., 221–228, 2016. © 2014 Society of Plastics Engineers

Stable radio-frequency phase distribution over optical fiber by phase-drift auto-cancellation.

We report a new radio-frequency (RF) phase stabilization approach for long-haul optical fiber distribution. The phase drift of an RF signal induced by fiber-length variations can be canceled out automatically via RF mixing without using active phase discrimination and dynamic phase tracking. A key significance of our approach is that no assistant local oscillator (LO) signal is needed. Consequently, frequency estimation of the received RF signal, as well as frequency locking between the LO and the received RF signal, is no longer required, which simplifies the system. A proof-of-concept experiment shows that the phase drift of the received RF signal at 9.6GHz is significantly reduced using the proposed method. The root mean square (RMS) timing jitter is 0.76ps when a tunable optical delay line (TODL) inserted between the remote antenna unit (RAU) and local station is changed from 0 to 300ps.

Synthesis and Characterization of Hardwickia Binata Fiber with Epoxy

For hundreds of year’s composite materials have been playing very crucial role in the field of materials. The applications of composites expanded widely to the aircraft, automotive, sporting goods, and biomedical industries. Today natural fibers like ramie, jowar, sisal, flax, hemp, jute, bamboo, banana, etc. are widely used than the synthetic fibers like glass, carbon, ceramic fibers, etc., because these natural fibres offer several advantages over synthetic fibres. In this project a new natural fiber is introduced to develop Fiber Reinforced Composite. Composite material is fabricated by hand lay-up method by using epoxy resin as the matrix and Hardwickia binata fiber as the reinforcing agent. Mechanical properties such as tensile and impact properties of Hardwickia binata fiber reinforced composites are investigated by varying fiber length and weight fraction. The composite plate is fabricated with different weight fractions of hardwickia binata fiber (5, 10, 15, 20, and 25 wt. %) and different lengths of the fiber (2, 3, 4, 5, and 6 mm). This paper concludes that, the tensile properties increases up to 20 wt. % fiber load with increasing fiber length while the impact properties increases with increasing fiber length and fiber load.

Research on Sliding Wear Behavior of TiO<sub>2</sub> Filled Glass Fiber Reinforced Polymer Composite

In this study, Titanium Oxide (TiO₂) particulate filled e-glass fiber reinforced composites in the unsaturated polyester resin matrix were prepared and its dry sliding wear behavior was optimized. Composites of varying fiber lengths of 1, 2 and 3 cm, respectively with different fiber content of 30, 40 and 50 wt. %, respectively were made. The particulate was varied with 2, 5 and 9 wt. %, respectively. The hybrid reinforced composites were prepared by hand layup method and the wear was measured adopting pin-on-disk system. Taguchi’s experimental design approach was used to make a parametric analysis of the variable fiber length, fiber content and filler material content. The influencing parameter on the wear rate was determined using the Signal-to-Noise (S/N) ratio and Analysis of Variance (ANOVA). The fiber content emerged as the most significant factor affecting the wear rate of the composites. The regression analysis was carried out to determine the nonlinear analysis for the prediction of the optimized model.

Thermal and Mechanical properties of epoxy-jute fiber composite

Chopped jute fiber-epoxy composites with varying fiber length (2-12 mm) and mass fraction (0.05-0.35) had been prepared by a heat press unit. The cross-linked product was characterized in terms of specific gravity, thermal conductivity, tensile strength, Young modulus and elongation at break. The transverse thermal conductivities for randomly oriented fibers in the composite were investigated by Lees and Charlton’s method. The tensile strength, Young modulus and elongation at break were investigated by a Universal Tensile Tester. With an increase in the fiber content (irrespective of the fiber length), the thermal conductivity of the composite decreases; the decreasing rate being highest for the fiber length of 2 mm followed by that for the fiber length of 6 and 12 mm. The decreasing rate of the thermal conductivity of the jute-epoxy composite is comparatively higher to that reported in literature for acrylic polymer hemp fiber composite. The tensile strength also decreases with the increase of the fiber content in the composite. The fiber length does not show to have significant effect on the tensile strength of the composite; the variation in strength being masked within experimental error. The Young modulus increases with the increase of fiber content within elastic limit; showing the highest values for the fiber length of 6 mm followed by those for the fiber length of 2 mm and 12 mm. The elongation at break shows slightly increasing trend up to 15% fiber content, but beyond that it decreases drastically. The specific gravity decreases with the increase in the fiber content and thus the recalculated specific tensile strength is found to keep at a stable level of 36MPa up to the fiber content of 20%, and beyond that the specific tensile strength decreases with the increase in the fiber content. It is concluded that jute fiber-epoxy composite could be used as a good heat-insulating material. Further investigation is recommended on the improvement of the thermal insulation keeping the mechanical properties unchanged or even improved. The TGA study is also required to ascertain the field of application of the material. DOI: http://dx.doi.org/10.3329/jce.v27i2.17807 Journal of Chemical Engineering, IEB Vol. ChE. 27, No. 2, December 2012: 77-82

A comparison of tensile properties of polyester composites reinforced with pineapple leaf fiber and pineapple peduncle fiber

Pineapple fiber which is rich in cellulose, relatively inexpensive, and abundantly available has the potential for polymer reinforcement. This research presents a study of the tensile properties of pineapple leaf fiber and pineapple peduncle fiber reinforced polyester composites. Composites were fabricated using leaf fiber and peduncle fiber with varying fiber length and fiber loading. Both fibers were mixed with polyester composites the various fiber volume fractions of 4, 8 and 12% and with three different fiber lengths of 10, 20 and 30 mm. The composites panels were fabricated using hand lay-out technique. The tensile test was carried out in accordance to ASTM D638. The result showed that pineapple peduncle fiber with 4% fiber volume fraction and fiber length of 30 mm give highest tensile properties. From the overall results, pineapple peduncle fiber shown the higher tensile properties compared to pineapple leaf fiber. It is found that by increasing the fiber volume fraction the tensile properties has significantly decreased but by increasing the fiber length, the tensile properties will be increased proportionally. Minitab software is used to perform the two-way ANOVA analysis to measure the significant. From the analysis done, there is a significant effect of fiber volume fraction and fiber length on the tensile properties.