Longer Fiber Length Research Articles

Enhancement of mechanical strength in lightweight EPS geopolymer composites using coconut fiber

This study examines the effect of coconut fiber (CF) on the mechanical properties of a sustainable building material known as lightweight ambient-cured geopolymer composites (CFLWGC). Coconut fibers, with mean diameter 0.4 mm and lengths of 2, 4, and 6 cm, were incorporated into the composite at varying contents (0.5%, 1%, 1.5%, and 2% by binder mass) to study their effect on CFLWGC. The resulting CFLWGC was thoroughly charaffigcterized for its physical and mechanical attributes, including density, workability, compressive strength, and splitting tensile strength. Results showed that incorporating coconut fibers significantly improved mechanical properties with optimal compressive strength of 11.265 MPa (30% increase) and highest split tensile strength of 1.464 MPa (35% improvement) at 4 cm fiber length and 1% content. However, excessive fiber volume or length reduced compressive strength to 7.821 MPa (25% decrease) and split tensile strength to 0.548 MPa (62.5% reduction). Longer fiber lengths (6 cm) and higher fiber contents generally decreased tensile strength, indicating that while moderate fiber addition enhances performance, excessive fiber volume or length negatively impacts the composites’ mechanical properties.

Transient gas-induced differential refractive index effects in as-drawn hollow core optical fibers

When a hollow core fiber is drawn, the core and cladding holes within the internal cane geometry are pressurized with an inert gas to enable precise control over the internal microstructure of the fiber and counteract surface tension forces. Primarily by considering the temperature drop as the fiber passes through the furnace and the geometrical transformation of the internal microstructure from preform-to-fiber, we recently established that the gas pressure within the final ‘as-drawn’ fiber is substantially below atmospheric pressure. We have also established that slight changes in the gas refractive index within the core and surrounding cladding holes induced by changes in gas pressure are sufficient to significantly affect both the modality and loss of the fiber. Here we demonstrate, through both simulations and experimental measurements, that the combination of these effects leads to transient changes in the fiber’s attenuation when the fibers are opened to atmosphere post-fabrication. It is important to account for this phenomenon for accurate fiber characterization, particularly when long lengths of fiber are drawn where it could take many weeks for every part of the internal microstructure to reach atmospheric pressure.

Three stage HCF fabrication technique for high yield, broadband UV-visible fibers.

Hollow-core optical fibers can offer broadband, single mode guidance in the UV-visible-NIR wavelength range, with the potential for low-loss, solarization-free operation, making them desirable and potentially disruptive for a wide range of applications. To achieve this requires the fabrication of fibers with <300nm anti-resonant membranes, which is technically challenging. Here we investigate the underlying fluid dynamics of the fiber fabrication process and demonstrate a new three-stage fabrication approach, capable of delivering long (∼350m) lengths of fiber with the desired thin-membranes.

Effects of fiber properties on flexural and fracture characteristics of manufactured sand concrete based on acoustic emission

Fiber-reinforced concrete (FRC) with natural sand (NS) as fine aggregate has been regarded as an favorable cementitious composites in engineering application due to its superior mechanical and fracture properties, etc. As a promising substitution for NS in conventional concrete, manufactured sand (MS) presents great potential in minimizing environmental impacts and increasing economic benefits. This paper presents the effects of fiber type (steel fiber, basalt fiber, glass fiber), fiber content (0 %, 1 %, 2 %) and fiber length (6 mm, 13 mm, 20 mm) on mechanical and fracture characteristics of manufactured sand concretes (MSCs) with 100 % replacement ratio of NS with MS. The entire fracture processes of MSCs were monitored using acoustic emissions (AE) in real time. The results showed that flexural strength of MSC increases with the addition of three different fibers, and steel fiber exhibits the best reinforcement effect. MSC with 1 % steel fiber content exhibits the highest flexural strength. Meanwhile, the longer the fiber length is, the smaller the flexural strength presents. The effects of fiber properties on AE parameters (count, b-value, information entropy) revealed that the addition of fibers reduces the fluctuation of counts and information entropy. The MSC with 2 % steel fiber content exhibits more dramatic fluctuations of b-value and information entropy after post-peak, which reveals greater internal damage in specimen. The longer the steel fiber is, the more dramatic the AE signal fluctuations and the more severe the damage inside the specimen emerge. Parametric analysis of rise angle (RA) and average frequency (AF) for classifying fracture modes (tensile and shear cracks) show that the incorporation of fibers can reduce the tensile cracks of MSC specimen under four-point bending. With the increase of fiber content, the tensile cracks first decrease and then increase. The longer fiber length is, the more tensile cracks generate during the fracture process.

Evaluation of Equivalent Thermal Conductivity for Carbon Fiber-Reinforced Bentonite through Experimental and Numerical Analysis

Bentonite is widely used as a water-proof material in engineering, and fibers are added to reduce the crack development of bentonite after drying. Carbon fiber can reinforce bentonite in heat-sensitive projects because of its high thermal conductivity and potential inhibition of bentonite cracking. Thus, it is important to determine the thermal conductivity of carbon fiber-reinforced bentonite. This study evaluated the thermal conductivity of carbon fiber-reinforced bentonite by analytical solution, experiment, and finite element method (FEM) simulation and discussed the effects of carbon fiber content, fiber length, fiber distribution, and the porosity of bentonite on the thermal conductivity of reinforced bentonite. The results show that the addition of carbon fiber can effectively improve the thermal conductivity of bentonite, and the thermal conductivity of the mixture is positively correlated with the content of fibers and the dry density of bentonite. When the content of carbon fiber with a thermal conductivity of 1000 W/(m K) is 1.0 %, and the porosity of bentonite is 0.4, the thermal conductivity of the composite can be increased by up to 390 %. At the same time, the distribution of fibers plays a vital role in thermal conductivity, and the thermal conductivity in the case of parallel distribution is 1.48 and 2.91 times that of random distribution and serial distribution. In addition, longer fiber length will help improve the thermal conductivity of the mixture. The thermal conductivity of the mixture for 1-inch fibers is 1.11 and 1.29 times that of 1/2-inch and 1/4-inch fibers. This study provides evidence of the possibility of improving the thermal conductivity of carbon fiber-reinforced bentonite.

Geographical provenance variation of growth and wood properties of 18-year-old Schima superba.

We analyzed the variation patterns of growth and wood properties of 24 different provenances of 18-year-old Schima superba in Jian'ou, Fujian Province. A total of 11 growth and wood indices were measured, including tree height, diameter at breast height, wood basic density and anatomical structure. We analyzed the geographical variation patterns of growth and wood properties, and the provenance areas were divided. Further, the excellent timber provenances were selected according to different uses. The results showed that the variation of growth traits, which was 17.6%-27.3% with mean value of 22.4%, was larger than that of wood properties (7.0%-21.0%, mean 12.7%). Growth properties and some wood properties (fiber length, fiber lumen diameter and fiber cell wall thickness) had significant differences among provenances. Growth traits were not correlated with fiber traits, and they could be selected independently without emphasis on other traits. There was significant correlation between the longitudinal and radial growth indicators of wood properties, but they were not correlated with the wood basic density, which could be selected independently. In addition, the growth and wood properties were significantly influenced by temperature and precipitation, which showed a latitudinal variation pattern. According to Q-type clustering analysis, 24 provenances could be divided into four categories, of which southern provenances from distribution area of S. superba had vigorous growth and supper wood properties. They had smaller microfibril angle, higher maturity, longer fiber length, and thicker fiber cell wall. Finally, five excellent provenances were selected according to pulpwood and building use.

Low soil available phosphorus level reduces cotton fiber length via osmoregulation.

Phosphorus (P) deficiency hinders cotton (Gossypium hirustum L.) growth and development, seriously affecting lint yield and fiber quality. However, it is still unclear how P fertilizer affects fiber length. Therefore, a two-year (2019-2020) pool-culture experiment was conducted using the split-plot design, with two cotton cultivars (CCRI-79; low-P tolerant and SCRC-28; low-P sensitive) as the main plot. Three soil available phosphorus (AP) contents (P0: 3 ± 0.5, P1: 6 ± 0.5, and P2 (control) with 15 ± 0.5 mg kg-1) were applied to the plots, as the subplot, to investigate the impact of soil AP content on cotton fiber elongation and length. Low soil AP (P0 and P1) decreased the contents of the osmotically active solutes in the cotton fibers, including potassium ions (K+), malate, soluble sugar, and sucrose, by 2.2-10.2%, 14.4-47.3%, 8.7-24.5%, and 10.1-23.4%, respectively, inhibiting the vacuoles from facilitating fiber elongation through osmoregulation. Moreover, soil AP deficiency also reduced the activities of enzymes participated in fiber elongation (plasma membrane H+-ATPase (PM-H+-ATPase), vacuole membrane H+-ATPase (V-H+-ATPase), vacuole membrane H+-translocating inorganic pyrophosphatase (V-H+-PPase), and phosphoenolpyruvate carboxylase (PEPC)). The PM-H+-ATPase, V-H+-ATPase, V-H+-PPase, and PEPC were reduced by 8.4-33.0%, 7.0-33.8%, 14.1-38.4%, and 16.9-40.2%, respectively, inhibiting the transmembrane transport of the osmotically active solutes and acidified conditions for fiber cell wall, thus limiting the fiber elongation. Similarly, soil AP deficiency reduced the fiber length by 0.6-3.0 mm, mainly due to the 3.8-16.3% reduction of the maximum velocity of fiber elongation (VLmax). Additionally, the upper fruiting branch positions (FB10-11) had higher VLmax and longer fiber lengths under low soil AP. Cotton fibers with higher malate content and V-H+-ATPase and V-H+-PPase activities yielded longer fibers. And the malate and soluble sugar contents and V-H+-ATPase and PEPC activities in the SCRC-28's fiber were more sensitive to soil AP deficiency in contrast to those of CCRI-79, possibly explaining the SCRC-28 fiber length sensitivity to low soil AP.

Wideband High-Speed and High-Accuracy Instantaneous Frequency Measurement System

A new photonic-assisted instantaneous frequency measurement system is presented. It overcomes the latency problem in the reported structures based on the frequency-to-time mapping technique or the frequency-to-power mapping technique that involves a long length of fiber, and at the same time, enables the incoming microwave signal frequency to be measured over a wide frequency range with only small errors. The system generates three low-frequency signals. The phases of the three low-frequency signals are compared. One of the two low-frequency signal phase differences is used to estimate the incoming microwave signal frequency unambiguously over a wide frequency range and the other is used to provide accurate microwave signal frequency measurement. A proof-of-concept experiment is set up. Experimental results show, by measuring the phase difference of two low-frequency signals, the frequency of the input microwave signal can be determined unambiguously in 15 GHz and 500 MHz frequency ranges with errors below ±220 MHz and ±10 MHz respectively. Hence, by using two low-frequency signal phase differences, the input microwave signal frequency can be determined accurately over a wide frequency range. The new photonic-assisted frequency measurement system has a fast response time, which is an order of magnitude shorter than that of the systems based on the frequency-to-time mapping technique and the frequency-to-power mapping technique with a kilometer-long fiber.

High bandwidth performance of multimode graded-index microstructured polymer optical fibers

The investigation of the bandwidth in multimode graded-index microstructured polymer optical fiber (GI mPOF) with a solid core is proposed using a modal diffusion approach. For a variety of launch radial offsets of multimode GI mPOF, bandwidth is reported by numerically solving the time-dependent power flow equation (TD PFE) using the explicit finite difference method (EFDM) and physics-informed neural networks (PINN). The decline in bandwidth with fiber length becomes slower at fiber lengths close to the coupling length Lc at which an equilibrium mode distribution (EMD) is attained, showing that mode coupling enhances bandwidth at longer fiber lengths. As fiber length is increased, bandwidth approaches complete independence from radial offset, suggesting the steady-state distribution (SSD) has been reached. We compare multimode GI mPOF performance in terms of bandwidth with that of traditional multimode GI POFs made of the same material. Higher bandwidth performance and quicker bandwidth improvement are displayed by the GI mPOF. To enhance fiber performance in GI mPOF links, such a fiber characterization can be used.

Dispersion turning point-enhanced photothermal interferometry gas sensor with an optical microfiber interferometer

Photothermal interferometry (PTI) spectroscopy is a background-free and ultrasensitive gas or chemical sensing method. To date, most works have focused on applying different techniques to improve the sensitivity of PTI gas sensors via enhancing the photothermal (PT) phase modulation. Herein, we develop an all-fiber dispersion turning point (DTP)-enhanced PTI gas sensor with a taper-based mode interferometer in which the PT phase detection sensitivity of the interferometer is enhanced in a millimeter-long single fiber PTI configuration, which has not been studied yet. The design is demonstrated by conducting the measurement of acetylene with a 3-mm-long, 2.29-μm-diamter microfiber interferometer. A lower detection limit of 965 parts per billion (ppb) acetylene is achieved when the probe wavelength is operating near DTP, showing 16 times enhancement. Besides, theoretical analysis shows that the sensitivity of phase detection would be enormously enhanced when the dispersion factor approaching zero. By optimal design of the taper-based mode interferometer, together with thinner fiber diameter and longer fiber length, gas detection may be further improved by double enhancement of both PT phase generation and phase detection. With advantages of high sensitivity, compact size and low cost, the proposed all-fiber DTP-enhanced PTI gas sensor is potentially promising for ultra-sensitive trace chemical or biochemical sensing.

Unique morphological architecture of the hamstring muscles and its functional relevance revealed by analysis of isolated muscle specimens and quantification of structural parameters.

The structural and functional differences of individual hamstrings have not been sufficiently evaluated. This study aimed to clarify the morphological architecture of the hamstrings including the superficial tendons in detail using isolated muscle specimens, together with quantification of structural parameters of the muscle. Sixteen lower limbs of human cadavers were used in this study. The semimembranosus (SM), semitendinosus (ST), biceps femoris long head (BFlh), and biceps femoris short head (BFsh) were dissected from cadavers to prepare isolated muscle specimens. Structural parameters, including muscle volume, muscle length, fiber length, sarcomere length, pennation angle, and physiological cross-sectional area (PCSA) were measured. In addition, the proximal and distal attachment areas of the muscle fibers were measured, and the proximal/distal area ratio was calculated. The SM, ST, and BFlh were spindle-shaped with the superficial origin and insertion tendons on the muscle surface, and the BFsh was quadrate with direct attachment to the skeleton and BFlh tendon. The muscle architecture was pennate in the four muscles. The four hamstrings possessed either of two types of structural parameters, one with shorter fiber length and larger PCSA, as in the SM and BFlh, and the other with longer fiber length and smaller PCSA, as in the ST and BFsh. Sarcomere length was unique in each of the four hamstrings, and thus the fiber length was suitably normalized using the average sarcomere length for each, instead of uniform length of 2.7μm. The proximal/distal area ratio was even in the SM, large in the ST, and small in the BFsh and BFlh. This study clarified that the superficial origin and insertion tendons are critical determinants of the unique internal structure and structural parameters representing the functional properties of the hamstring muscles.

100 years of Brillouin scattering: Historical and future perspectives

The Year 2022 marks 100 years since Leon Brillouin predicted and theoretically described the interaction of optical waves with acoustic waves in a medium. Accordingly, this resonant multi-wave interaction is referred to as Brillouin scattering. Today, Brillouin scattering has found a multitude of applications, ranging from microscopy of biological tissue, remote sensing over many kilometers, and signal processing in compact photonic integrated circuits smaller than the size of a thumbnail. What allows Brillouin scattering to be harnessed over such different length scales and research domains are its unique underlying properties, namely, its narrow linewidth in the MHz range, a frequency shift in the GHz range, large frequency selective gain or loss, frequency tunability, and optical reconfigurability. Brillouin scattering is also a ubiquitous effect that can be observed in many different media, such as freely propagating in gases and liquids, as well as over long lengths of low-loss optical glass fibers or short semiconductor waveguides. A recent trend of Brillouin research focuses on micro-structured waveguides and integrated photonic platforms. The reduction in the size of waveguides allows tailoring the overlap between the optical and acoustic waves and promises many novel applications in a compact footprint. In this review article, we give an overview of the evolution and development of the field of Brillouin scattering over the last one hundred years toward current lines of active research. We provide the reader with a perspective of recent trends and challenges that demand further research efforts and give an outlook toward the future of this exciting and diverse research field.

Simulation Assessment of Inlet Parameters and Membrane-Surface-Structure Effects on CO2 Absorption Flux in Membrane Contactors

The management of global carbon dioxide (CO2) emissions is considered one of the main environmental problems facing the modern world. One of the potential techniques for CO2 capture is absorption, using membrane contactor modules. Most of the previous research that dealt with membrane contactor simulations considered the whole membrane surface as the active reaction surface. However, in this paper, a more realistic model of the membrane-contactor module is presented, taking into account the effects of the pore size and surface porosity. CO2 absorption into the monoethanolamine (MEA) solution in hollow fiber membrane-contactor modules was numerically investigated. A computational fluid dynamics simulation was established using essential basic fluid dynamics and mass transfer equations in reactive mode. An algorithmic function was used to present the relations between the CO2 absorption flux and the hollow fiber length, membrane surface pore size, and porosity. The simulation results were compared to previously obtained experimental results without using any fitting parameters, and a good agreement was found with an average error of 8.5%. The validated simulation was then used to predict the effects of the MEA inlet velocity and concentration, the membrane surface pore size, and porosity on the total CO2 absorption flux. A maximum absorption flux of about 1.8 mol/m2·s was achieved at an MEA concentration of 4 M with a pore size of 0.2 microns, a surface porosity of 1%, and an inlet velocity of 0.25 m/s. The extrapolation technique was then used to predict the values of the absorption flux at longer fiber lengths. The concentration profiles around the pores at the gas–liquid contact surface of the membrane were obtained and presented. The proposed model exhibited excellent potential to evaluate the effective reaction surface in hollow fiber membrane contactors. This model could be considered the first step to obtaining accurate predictions of the membrane contactor gas absorption performance based on its surface structure.

Influence of the Width of Launch Beam Distribution on the Transmission Performance of Seven-Core Polymer-Clad Silica Fibers

We propose a space division multiplexing (SDM) in a newly constructed multicore polymer-clad silica fiber (PCSF) with seven cores arrayed in a hexagonal array, each carrying a centrally launched beam. This enables a higher SDM capacity at longer fiber lengths in the proposed seven-core PCSF if compared with previously proposed angular division multiplexing (ADM) in single-core (SC) PCSF. As a result, the SDM is not limited to short fiber lengths in the proposed seven-core PCSF, as it is in the case of the ADM channels due to mode coupling in the SC PCSF. In addition, the time-independent power flow equation (TI PFE) is used to analyze the effect of the width of the launch beam distribution on the equilibrium mode distribution (EMD) and steady state distribution (SSD) in each of the seven cores of the investigated PCSF. The width of the launch beam distribution has a considerable impact on the fiber length at which the EMD and SSD are attained, according to our numerical results. Thus, by decreasing the full width at half maximum (FWHM) of the launch beam distribution from 20 to 2°, the length at which EMD is established increases from Lc = 1020 to 1250 m, and the length at which SSD is attained increases from zs = 2650 to 3250 m. A narrow launch beam distribution leads to higher bandwidth at small and intermediate fiber lengths. On the other hand, at shorter fiber lengths, a wider launch beam distribution induces a bandwidth change from 1/z proportional to 1/z1/2 proportional curve, e.g., a slower bandwidth reduction. When building a multicore optical fiber transmission system for SDM, such characterization of multicore PCSFs under various launch conditions should be taken into account.

Manufacturing of Fluff Pulp Using Different Pulp Sources and Bentonite on an Industrial Scale for Absorbent Hygienic Products

In this study, for the first time, a composite fluff pulp was produced based on the combination of softwood (i.e., long-length fiber), hardwood (i.e., short-length fiber), non-wooden pulps (i.e., bagasse) and bentonite, with specific amounts to be used in hygienic pads (e.g., baby diapers and sanitary napkins). After the defibration process, the manufactured fluff pulp was placed as an absorbent mass in diapers and sanitary napkins. Therefore, tests related to the fluff pulp, such as grammage, thickness, density, ash content, humidity percentage, pH and brightness, tests related to the manufactured baby diapers, such as absorption capacity, retention rate, retention capacity, absorption time and rewet, and tests related to the sanitary napkin, such as absorption capacity and rewet, were performed according to the related standards. The results demonstrated that increasing the amount of bagasse pulp led to increasing the ash content, pH and density of fluff pulp and decreasing the brightness. The addition of bentonite as a filler also increased ash content and pH of fluff pulp. The results also demonstrated that increasing of bagasse pulp up to 30% in combination with softwood pulp led to increasing absorption capacity, retention rate, retention capacity, absorption time and rewet of baby diapers and of sanitary napkins.

Effects of Fiber Volume Fraction and Length on the Mechanical Properties of Milled Glass Fiber/Polyurea Composites.

Composites of polyurea (PU) reinforced with milled glass fiber (MGf) were fabricated. The volume fraction and length of the milled glass fiber were varied to study their effects on the morphological and mechanical properties of the MGf/PU composites. The morphological attributes were characterized with scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. The SEM investigations revealed a uniform distribution and arbitrary orientation of milled glass fiber in the polyurea matrix. Moreover, it seems that the composites with longer fiber exhibit better interfacial bonding. It was found from the FTIR studies that the incorporation of milled glass fiber into polyurea leads to more phase mixing and decreases the hydrogen bonding of the polyurea matrix, while having a negligible effect on the H-bond strength. The compression tests at different strain rates (0.001, 0.01, 0.1, 1, 2000 and 3000 s−1) and dynamic mechanical properties over the temperature range from −30 to 100 °C at 1 Hz were performed. Experimental results show that the compressive behavior of MGf/PU composites is nonlinear and strain-rate-dependent. Both elastic modulus and flow stress at any given strain increased with strain rate. The composites with higher fiber volume fraction and longer fiber length are more sensitive to strain rate. Furthermore, the elastic modulus, stress at 65% strain and energy absorption capability were studied, taking into account both the effect of fiber volume fraction and mean fiber length. It is noted that an increase in fiber volume fraction and fiber length leads to an increase in elastic modulus, stress at 65% strain and absorbed energy up to ~103%, 83.0% and 137.5%, respectively. The storage and loss moduli of the composites also increase with fiber volume fraction and fiber length. It can be concluded that the addition of milled glass fiber into polyurea not only improves the stiffness of the composites but also increases their energy dissipative capability.

Fabrication and Properties of Tree-Branched Cellulose Nanofibers (CNFs) via Acid Hydrolysis Assisted with Pre-Disintegration Treatment.

In this paper, the novel morphology of cellulose nanofibers (CNFs) with a unique tree-branched structure was discovered by using acid hydrolysis assisted with pre-disintegration treatment from wood pulps. For comparison, the pulps derived from both softwood and hardwood were utilized to extract nanocellulose in order to validate the feasibility of proposed material fabrication technique. The morphology, crystalline structures, chemical structures, and thermal stability of nanocellulose were characterized by means of transmission electron microscopy (TEM), X-ray diffraction (XRD) analysis, Fourier transform infrared spectroscopy (FTIR), as well as thermogravimetric analysis (TGA). Prior to acid hydrolysis, softwood and hardwood pulps underwent the disintegration treatment in the fiber dissociator. It has been found that nanocellulose derived from disintegrated pulps possesses much longer fiber length (approximately 5–6 μm) and more evident tree-branched structures along with lower degree of crystallinity when compared with those untreated counterparts. The maximum mass loss rate of CNFs takes place at the temperature level of approximately 225 °C, and appears to be higher than that of cellulose nanowhiskers (CNWs), which might be attributed to an induced impact of amorphous content. On the other hand, disintegration treatment is quite beneficial to the enhancement of tensile strength of nanocellulose films. This study elaborates a new route of material fabrication toward the development of well-tailored tree-branched CNFs in order to broaden the potential widespread applications of nanocellulose with diverse morphological structures.

Novel Measurement-Based Efficient Computational Approach to Modeling Optical Power Transmission in Step-Index Polymer Optical Fiber

Polymer optical fibers (POFs) are playing an important role in industrial applications nowadays due to their ease of handling and resilience to bending and environmental effects. A POF can tolerate a bending radius of less than 20 mm, it can work in environments with temperatures ranging from −55 °C to +105 °C, and its lifetime is around 20 years. In this paper, we propose a novel, rigorous, and efficient computational model to estimate the most important parameters that determine the characteristics of light propagation through a step-index polymer optical fiber (SI-POF). The model uses attenuation, diffusion, and mode group delay as functions of the propagation angle to characterize the optical power transmission in the SI-POF. Taking into consideration the mode group delay allows us to generalize the computational model to be applicable to POFs with different index profiles. In particular, we use experimental measurements of spatial distributions and frequency responses to derive accurate parameters for our SI-POF simulation model. The experimental data were measured at different fiber lengths according to the cut-back method. This method consists of taking several measurements such as frequency responses, angular intensity distributions, and optical power measurements over a long length of fiber (&gt;100 m), then cutting back the fiber while maintaining the same launching conditions and repeating the measurements on the shorter lengths of fiber. The model derivation uses an objective function to minimize the differences between the experimental measurements and the simulated results. The use of the matrix exponential method (MEM) to implement the SI-POF model results in a computationally efficient model that is suitable for POF-based system-level studies. The efficiency gain is due to the independence of the calculation time with respect to the fiber length, in contrast to the classic analytical solutions of the time-dependent power flow equation. The robustness of the proposed model is validated by calculating the goodness-of-fit of the model predictions relative to experimental data.

Development and Utilization of Functional Kompetitive Allele-Specific PCR Markers for Key Genes Underpinning Fiber Length and Strength in Gossypium hirsutum L.

Fiber length (FL) and fiber strength (FS) are the important indicators of fiber quality in cotton. Longer and stronger fibers are preferred for manufacturing finer yarns in the textile industry. Functional markers (FMs) designed from polymorphic sites within gene sequences attributing to phenotypic variation are highly efficient when used for marker-assisted selection (MAS) in breeding superior varieties with longer FL and higher FS. The aims of this study were to develop FMs via kompetitive allele-specific PCR (KASP) assays and to validate the efficacy of the FMs for allele discrimination and the potential value in practice application. We used four single-nucleotide polymorphism markers and 360 cotton accessions and found that two FMs, namely, D11_24030087 and A07_72204443, could effectively differentiate accessions of different genotypes with higher consistency to phenotype. The appeared frequencies of varieties harbored Hap2 (elite alleles G and T) with longer FL (> the mean of accessions with non-elite allele, 28.50 mm) and higher FS (> the mean of accessions with non-elite allele, 29.06 cN•tex–1) were 100 and 72.7%, respectively, which was higher than that of varieties harbored only on a single elite allele (G or T, 77.9 or 61.9%), suggesting a favorable haplotype for selecting varieties with superior FL and FS. These FMs could be valuable for the high-throughput selection of superior materials by providing genotypic information in cotton breeding programs.

Extraction and Isolation of Cellulose Nanofibers from Carpet Wastes Using Supercritical Carbon Dioxide Approach.

Cellulose nanofibers (CNFs) are the most advanced bio-nanomaterial utilized in various applications due to their unique physical and structural properties, renewability, biodegradability, and biocompatibility. It has been isolated from diverse sources including plants as well as textile wastes using different isolation techniques, such as acid hydrolysis, high-intensity ultrasonication, and steam explosion process. Here, we planned to extract and isolate CNFs from carpet wastes using a supercritical carbon dioxide (Sc.CO2) treatment approach. The mechanism of defibrillation and defragmentation caused by Sc.CO2 treatment was also explained. The morphological analysis of bleached fibers showed that Sc.CO2 treatment induced several longitudinal fractions along with each fiber due to the supercritical condition of temperature and pressure. Such conditions removed th fiber’s impurities and produced more fragile fibers compared to untreated samples. The particle size analysis and Transmission Electron Microscopes (TEM) confirm the effect of Sc.CO2 treatment. The average fiber length and diameter of Sc.CO2 treated CNFs were 53.72 and 7.14 nm, respectively. In comparison, untreated samples had longer fiber length and diameter (302.87 and 97.93 nm). The Sc.CO2-treated CNFs also had significantly higher thermal stability by more than 27% and zeta potential value of −38.9± 5.1 mV, compared to untreated CNFs (−33.1 ± 3.0 mV). The vibrational band frequency and chemical composition analysis data confirm the presence of cellulose function groups without any contamination with lignin and hemicellulose. The Sc.CO2 treatment method is a green approach for enhancing the isolation yield of CNFs from carpet wastes and produce better quality nanocellulose for advanced applications.