Fiber Configuration Research Articles

Ultrahigh-resolution and ultra-simple fiber-optic sensor with resonant Sagnac interferometer.

The resonant fiber-optic sensor (RFOS) is well known for its high sensing resolution but usually suffers from high cost and system complexity. In this Letter, we propose an ultra-simple white-light-driven RFOS with a resonant Sagnac interferometer. By superimposing the output of multiple equivalent Sagnac interferometers, the strain signal is amplified during the resonance. A 3 × 3 coupler is employed for demodulation, by which the signal under test can be read out directly without any modulation. With 1 km delay fiber and ultra-simple configuration, a strain resolution of 28f ε/Hz at 5 kHz is demonstrated in the experiment, which is among the highest, to the best of our knowledge, resolution optical fiber strain sensors.

Highly thermal conductive Csf/Mg composites by in-situ constructing the unidirectional configuration of short carbon fibers

Lightweight, low cost, and high thermal conductivity (TC) are crucial targets for thermal management material development. Short carbon fiber reinforced metal matrix composites (MMCs) have attracted extensive attention due to the aforementioned superiorities. Despite compositing short carbon fibers capable of improving the TC of metals to a certain extent, the enhancement efficiency is not satisfactory till now due to the significant anisotropy of fibers. Inspired by the pressure stacking phenomenon of short fibers and using an independently designed preform-forming mold, combined with the Liquid-solid extrusion following vacuum infiltration (LSEVI) technique, we propose a novel technique that could in situ construct the short carbon fiber unidirectional configuration in the AZ91D matrix. According to micro-CT test results and using image processing technology, the high TC of 106.7 W/mK was achieved due to the highly aligned short carbon fibers, which is equivalent to 122.2% enhancement compared to the AZ91D matrix. And the specific TC enhancement efficiency (σ) is significantly higher than that of the prior reports. Furthermore, the short carbon fiber reinforced magnesium (Csf/Mg) composites possess excellent heat conduction capacity compared to the AZ91D magnesium alloy, according to the thermal management capability test experiment. Our results not only chalk up a record value σ for short carbon fiber reinforced MMCs, but also provide a road map for future employing the Csf/Mg composites in the field of thermal management.

Strain-based forward modeling and inversion of seismic moment tensors using distributed acoustic sensing (DAS) observations

This study used a waveform inversion of distributed acoustic sensing (DAS) data, acquired in two horizontal monitoring wells, to estimate the moment tensor (MT) of two induced microearthquakes. An analytical forward model was developed to simulate far-field tangential strain generated by an MT source in a homogeneous and anisotropic medium, averaged over the gauge length along a fiber of arbitrary orientation. To prepare the data for inversion, secondary scattered waves were removed from the field observations, using f-k filtering and time-windowing. The modeled and observed primary arrivals were aligned using a cut-and-paste approach. The MT parameters were inverted via a least-squares approach, and their uncertainties were determined through bootstrap analysis. Using simulated data with additive noise derived from the field data and the same fiber configuration as the monitoring wells, the inversion method adequately resolved the MT. Despite the assumption of Gaussian noise, which underlies the least-squares inversion approach, the method was robust in the presence of heavy-tailed noise observed in field data. When the inversion was applied to field data, independent inversion results using P-waves, S-waves, and both waves together yielded results that were consistent between the two events and for different wave types. The agreement of the inversion results for two events resulting from the same stress field illustrated the reliability of the method. The uncertainties of the MT parameters were small enough to make the inversion method useful for geophysical interpretation. The variance reduction obtained from the data predicted for the most probable MT was satisfying, even though the polarity of the P-waves was not always correctly reproduced.

Taguchi optimized sliding wear behavior and hardness of novelGrewia optiva/Basalt fiber reinforced hybrid polyester composites

AbstractThis research paper investigated the hardness and tribological performance of novelGrewia optiva/Basalt fiber reinforced hybrid polymer composites. Two different configuration of hybrid composite that is, woven and chopped fiber reinforced composite are considered for the study. The chopped fiber configuration of the composite is further divided into two types based on fiber length and wt%. The fiber lengths studied are 6 and 12 mm while the wt% studied are 0, 6, and 12 wt%. Woven fiber reinforced composite is divided into five configurations based on wt% ofG. optivafiber with 0, 3, 6, 9, and 12 wt%. In all configurations, maximum fiber content of 12 wt% is maintained. B6/GO6 composite exhibits minimum specific wear rate and maximum hardness among all the compositions. Wear experimental results are analyzed by Taguchi optimization technique and based on the five levels and four control factors (sliding velocity, fiber loading, sliding distance, and normal load) L25partial orthogonal array was suggested for the woven fiber reinforced composites. Fiber content is the main control parameter for hardness testing and L9orthogonal array was suggested according to four control factors and three levels.

PULM2: Combining Extracorporeal Lung and Kidney Support: Evaluation of Fibre Configurations on Gas Exchange Preservation for the Development of a Novel Highly Integrated Device (RenOx)

Background: Combined lung and kidney dysfunction are frequent in extracorporeal membrane oxygenation (ECMO) patients affecting up to 70% of them. Current treatment relies on the use of two separate circuits combining ECMO and renal replacement therapy, increasing infection risks and the use of artificial surfaces. Therefore, we aim to develop a novel artificial lung that integrates lung and kidney support in a single device combining oxygenation and hemodialysis fibers. Thus, we analyzed how many oxygenation fibers could be substituted by hemodialysis fibers while still maintaining 90% of the oxygenator’s gas exchange capacity and the effect fiber configuration has on oxygen (O2) and carbon dioxide (CO2) transfer. Methods: Fiber bundles were composed of oxygenation fiber mats (Oxyplus™ 90/200, 3M) stacked perpendicularly at a 90° angle and/or crossed at a 24° angle on top of each other. We manufactured bundles with all oxygenation fibers open and bundles with oxygenation fibers closed in a way that they could not contribute to gas exchange, simulating hemodialysis fibers. Bundles in perpendicular configuration had 100% of fibers open (Oxy100P), 50% of fibers closed (Oxy50P), or 25% of fibers closed (Oxy75P), Figure 1. Bundles in crossed configuration had all fibers open (Oxy100C) or 33% of fibers closed (Oxy67C). Bundles were tested for gas exchange performance following in-vitro blood tests according to ISO 7199:2016. Results: Our results show that bundles with 25% of oxygenation fibers closed in perpendicular configuration were able to still maintain 90% of the O2 exchange and 80% of the CO2 exchange capacity of our oxygenator. Bundles with 25% oxygenation fibers closed had no statistically significant difference in O2 or CO2 transfer compared to a fully open oxygenator with the same fiber configuration, Figure 2. Additionally, Oxy75P bundles were able to keep O2 delivery above 55 mL/LBlood flow and CO2 removal above 52 mL/LBlood flow up to 140 mL/min. Fiber configuration did not affect gas exchange for fully open bundles, however, configuration significantly influenced O2 and CO2 exchange for bundles with closed fiber layers. Closing fibers in perpendicular configuration resulted in a lower decrease in gas transfer. Below 140 mL/min, this was demonstrated by a similar decrease in O2 transfer of 20% when 50% of perpendicular fibers or 33% of crossed fibers were closed Conclusions: We analyzed the effect of replacing oxygenation fibers with hemodialysis fibers on gas exchange efficiency. Our results demonstrate that 25% of oxygenation fibers in a perpendicular configuration could be replaced by hemodialysis fibers while still maintaining 90% of the O2 exchange of our oxygenator. Moreover, this type of bundle kept O2 delivery above 55 mL/LBlood flow up to 140 mL/min. This shows that gas exchange can be preserved to a desirable extent when oxygenation fiber layers are replaced. This is a step towards combining lung and kidney support in a single device.Figure 1. Illustration of a device combining extracorporeal lung and kidney support. Oxygen flows through the lumen of oxygenation fibers and dialysate flows inside hemodialysis fibers. In this work, fiber bundles were manufactured with a perpendicular and/or crossed configuration having a varying number of oxygenation fiber layers closed, simulating hemodialysis fibers (open fibers in white and closed fibers in blue). Perpendicular bundles had 50% of fibers closed (Oxy50P), 25% of fibers closed (Oxy75P), or 100% of fibers open (Oxy100P), while crossed bundles had 33% of fibers closed (Oxy67C), or all fibers open (Oxy100C).Figure 2. Oxygen exchange performance mL/LBlood flow ± standard deviation from the mean (n = 10) for bundles with different fiber configurations. We found no statistically significant difference in mean oxygen exchange between Oxy75P and the fully open oxygenator Oxy100P (ANOVA p > 0.38).

Highly efficient ampere-level CO2 reduction to multicarbon products via stepwise hollow-fiber penetration electrodes

Efficient C2+ production from CO2 electrocatalytic reduction exhibits significant promise but suffers from low selectivity and undesired side reactions. Stepwise electroreductions of CO2 to CO and then to C2+ products can benefit from the perfect cooperation of the first high CO production efficiency and the subsequent favorable C-C coupling kinetics of CO. Herein, by virtue of serial Ag and Cu hollow-fiber penetration electrodes, a high-efficiency CO2 electroreduction to C2+ products is achieved with a partial current density of 1.8 A cm−2 and a faradaic efficiency of 90.5 %. Experimental results and density functional theory calculations demonstrate that the synergetic combination of unique penetration effect induced by hierarchical micro/nanostructured hollow fiber configurations and regulated electronic structures by chloride ion adsorption, is responsible for the superior activity. This work provides a facile tactic and encouraging headway to design applicable efficient CO2 electrocatalytic reduction systems towards high-value C2+ chemicals.

Configuration of elastin fibers in the intra- and extra-capsule ligaments of the elderly cricoarytenoid joint

PurposeTo define the localization and configuration of the elastic fibers of the cricoarytenoid ligament (CAL) and their relationship with the cricoarytenoid joint (CAJ) capsule.MethodsTwenty-four CAJs from twelve cadavers were analyzed using Verhoeff-Van Gieson staining, and immunohistochemistry methods. This is a prospective study.ResultsThe CAL was classified into two parts: an extra-capsular anterior-CAL and an intra-capsular posterior-CAL. The both parts contained rich elastic fibers. The elastic fibers of the anterior-CAL were orientated in both anterior–posterior and superior–inferior directions and under a relaxation status, whereas the elastic fibers of the posterior-CAL were arranged in a lateral–medial direction and under a taut status.ConclusionsThis study defined the fine configuration of the CAL, particularly its elastic fibers, which may help us to better understand the biomechanics of the CAJ motions, and differential diagnosis of CAJ disorders. The results of the study re-confirm that the P-CAL is the key posterior–lateral passive force to limit the mobility of the muscular process of the arytenoid cartilage and stabilize the CAJ, whereas the A-CAL may protect the CAJ from an over superior–lateral–posterior motion.Level of evidence: H/A.

Effect of hollow fiber configuration and replacement on the gas exchange performance of artificial membrane lungs

Artificial membrane lungs are composed of hollow fiber membranes. Blood flows with low velocities in the membrane bundle, forming a laminar boundary layer near the membrane surfaces that limits gas transfer. Passive blood mixing within the fiber array is utilized to overcome this limitation. Nevertheless, it is unclear to which extent blood mixing and fiber configuration contribute to the performance of membrane oxygenators.This study aims to evaluate the effect of fiber configuration and replacement on the gas exchange performance of membrane oxygenators to contribute to a better understanding of the influence of blood mixing to gas transfer and the mechanisms of gas exchange in blood. Furthermore, designs in which hollow fibers of different functions could be combined in highly integrated membrane lungs are provided.We analyzed the gas transfer performance of membrane oxygenators in a perpendicular configuration with 100%, 75%, or 50% of fibers open, and in a crossed configuration with 100% or 67% of fibers open. 95%–100% of the oxygen transfer of a fully open oxygenator could be maintained in our prototypes with 25% of gas exchange fibers closed in a perpendicular configuration, indicating that several fibers contributed to gas exchange by mixing the blood flow. Closing fibers in a perpendicular configuration resulted in a lower decrease in oxygen transfer. This study contributes to the development of novel membrane oxygenators integrating fibers of different functionalities (e.g. oxygenation and dialysis) maintaining high gas exchange efficiency.

The History of Electrospinning: Past, Present, and Future Developments

AbstractElectrospinning has rapidly progressed over the past few decades as an easy and versatile way to fabricate fibers with diameters ranging from micrometers to tens of nanometers that present unique and intricate morphologies. This has led to the conception of new technologies and diverse methods that exploit the basic electrohydrodynamic phenomena of the electrospinning process, which has in turn led to the invention of novel apparatuses that have reshaped the field. Research on revamping conventional electrospinning has principally focused on achieving three key objectives: upscaling the process while retaining consistent morphological traits, developing 3D nanofibrous macrostructures, and formulating novel fiber configurations. This review introduces an extensive group of diverse electrospinning techniques and presents a comperative study based on the apparatus type and output. Then, each process's advantages and limitations are critically assessed to identify the bona fide practicability and relevance of each technological breakthrough. Finally, the outlook on future developments of advanced electrospinning technologies is outlined, with an emphasis on upscaling, translational research, sustainable manufacturing and prospective solutions to current shortcomings.

Modeling of hollow fiber facilitated transport membrane modules for post combustion carbon capture process: Evaluation of non-ideal effect and module characteristic

Membrane separation technology has been regarded as a promising alternative for carbon capture process due to its low consumption and low footprint. Facilitated transported membranes exhibit attractive CO2/N2 separation performance due to the existence of CO2-philic reactive carriers. However, the highly pressure and temperature dependent CO2 permeance of it, as well as non-ideal effect, make the simulation of carbon capture process based on simplifying model challenging. Herein, we established a rigorous model for hollow fiber facilitated transport membrane considering both non-ideal effect and variable permeance. This rigorous model was applied for post-combustion carbon capture, and compared with simple model which only considering variable permeance. It was found that rigorous model has a 44%-55% lower carbon capture capacity due to the declined driving force and permeance. Pressure loss accounts for the deviation at low stage cut (10%), while Joule-Thomson effect and concentration polarization effect become greater at high stage cut (20%). Thanks to the mild condition of post combustion flue gas, the impact of real gas behavior can be neglected. Moreover, the attractive configuration of hollow fiber facilitated transport membrane was found to be with relative short fiber length, moderate packing fraction and large fiber inner diameter.

Macro synthetic fiber pullout behavior in short- and long-term tests

The creep phenomenon in fiber-reinforced composites is particularly important when synthetic macro fibers are used. In addition to the low modulus of elasticity, the polymers used in fibers have pronounced viscoelastic behavior even at room temperature, which can lead to changes in the cracking control over time. The long-term fiber pullout response also results from fiber and interface creep contributions. To understand the above phenomena, pullout tests with short- and long-term loads were conducted on three types of polymeric macro fibers subject to different levels of long-term loads (20, 30, 40 and 50%). The results of the pullout tests were strongly dependent on the fiber configuration, surface corrugation and modulus of elasticity. Macro fibers with crimped surfaces and higher modulus of elasticity achieved higher bond stresses and lower creep deformations. The Burgers model was applied and showed a good agreement with the experimental creep curves, therefore consisting of a promising alternative for modeling long-term behavior. Microtomography and scanning electron microscopy images showed that a large portion of the strain in tension, under sustained load, can be attributed to the creep of the fiber itself, thus making it challenging to estimate the creep of this type of composite, given the considerable variability of fiber configurations.

Adaptive inverse mapping: a model-free semi-supervised learning approach towards robust imaging through dynamic scattering media.

Imaging through scattering media is a useful and yet demanding task since it involves solving for an inverse mapping from speckle images to object images. It becomes even more challenging when the scattering medium undergoes dynamic changes. Various approaches have been proposed in recent years. However, none of them are able to preserve high image quality without either assuming a finite number of sources for dynamic changes, assuming a thin scattering medium, or requiring access to both ends of the medium. In this paper, we propose an adaptive inverse mapping (AIP) method, which requires no prior knowledge of the dynamic change and only needs output speckle images after initialization. We show that the inverse mapping can be corrected through unsupervised learning if the output speckle images are followed closely. We test the AIP method on two numerical simulations: a dynamic scattering system formulated as an evolving transmission matrix and a telescope with a changing random phase mask at a defocused plane. Then we experimentally apply the AIP method to a multimode-fiber-based imaging system with a changing fiber configuration. Increased robustness in imaging is observed in all three cases. AIP method's high imaging performance demonstrates great potential in imaging through dynamic scattering media.

Seismic Behavior of Concrete Bridge Piers Reinforced with Steel or GFRP Bars

This paper evaluates the seismic behavior of eight one-third-scale concrete bridge piers reinforced with various configurations of steel or glass fiber–reinforced polymer (GFRP) bars. Each specimen was tested under a constant axial gravity load, combined with reversed quasistatic cyclic lateral loading. The behavior of the piers was assessed and compared in terms of strength, stiffness, deformability, energy dissipation, and damage. The results indicate that well-detailed hybrid configurations with steel longitudinal bars and GFRP spirals offer a ductile seismic response with reduced postpeak strength degradation. The GFRP spirals were effective in confining the concrete core and restraining longitudinal bar buckling. Piers reinforced with GFRP longitudinal and transverse bars exhibit a stable and deformable seismic response with little residual displacement or strength degradation. However, this behavior was accompanied by a reduction in effective stiffness exceeding 40% and approximately half the hysteretic energy dissipation at an equivalent drift level. All piers reinforced with GFRP bars or spirals exceeded lateral drift requirements set by North American codes.

Investigation of Different Types of Fibers for Roads by CBR Tests

In this study, California Bearing Ratio (CBR) tests in a laboratory were performed to observe the behaviour of granular layer fills reinforced with discrete fibers. Six different fiber types were used in granular road layer by using different methods. Firstly, fibers were added in the road as a layer, then they mixed with soil particles, and as a third method they mixed with soil by laying a geotextile in the road layer, in other words it was used as combine reinforced model. And as the last method only a geotextile was laid and used in the pavement soil. By using these methods, the influence of different type of reinforcements on CBR and bearing capacity ratio values were investigated. Additionally, effects on the pavement layer thickness were calculated and for the best configuration of fiber reinforced sample a cost analysis was conducted. As a result of the study, CBR test values for each fiber type used in the study have different values, and for small penetration levels some test results show no improvement for bearing capacity ratio of the road. It was noticed that when increasing the penetration level, the bearing capacity ratios have larger values. Thus, cost and layer thickness numbers were various for different reinforced road layer models. Therefore, in the real life road projects before using fiber types, cost and performance analysis should be made to determine the more effective one.

Measurement of microfibril angle in plant fibres: Comparison between X-ray diffraction, second harmonic generation and transmission ellipsometry microscopies

The orientation of cellulose microfibrils within plant fibres is one of the main factors influencing their mechanical properties. As plant fibres are more and more used as reinforcement for agro-composites, their mechanical properties have a strong influence on the final composite properties. It is, therefore, of interest to obtain reliable information about the microfibril angle (MFA) to better support the choice of fibres depending on the product requirements. In the present study, the reliability and specificities of three non-destructive methods that allow analysis on the same fibre glued on a holder; X-ray diffraction (XRD), second harmonic generation (SHG) and transmission ellipsometry (TE) microscopy; are investigated. Three types of plant fibres, with both low (nettle), and high (cotton, sisal) MFA values, are compared and their geometry and biochemical composition are characterised. The results obtained on the same fibre confirm that MFA analysis remains tedious and that despite their limitations, the methods are complementary depending on the information requested. Indeed, SHG is recommended for direct, qualitative and plane-selective mapping of heterogeneities in macrofibril orientations at various depths. However, reliable quantitative results with SHG depend on the initial image quality and could benefit from further image processing refinement. On the contrary, XRD and TE measure MFAs over the entire fibre thickness and provide variations along the fibres if a sufficient optical/spatial resolution is reached. Regarding the characterization of intrinsic defects in plant fibres, both SHG and TE suffer from uncertainties induced by the disorganization of the microfibril network and the lack of symmetry between the front and back fibre walls. Finally, all techniques prove to be dependant on the initial fibre alignment and geometry (i.e. twisting, double fibre configuration or form factor) which vary along the fibre length and should be carefully taken into account.

A novel framework for in-vivo diffusion tensor distribution MRI of the human brain

Neural tissue microstructure plays an important role in developmental, physiological and pathophysiological processes. Diffusion tensor distribution (DTD) MRI helps probe subvoxel heterogeneity by describing water diffusion within a voxel using an ensemble of non-exchanging compartments characterized by a probability density function of diffusion tensors. In this study, we provide a new framework for acquiring multiple diffusion encoding (MDE) images and estimating DTD from them in the human brain in vivo. We interfused pulsed field gradients (iPFG) in a single spin echo to generate arbitrary b-tensors of rank one, two, or three without introducing concomitant gradient artifacts. Employing well-defined diffusion encoding parameters we show that iPFG retains salient features of a traditional multiple-PFG (mPFG/MDE) sequence while reducing the echo time and coherence pathway artifacts thereby extending its applications beyond DTD MRI. Our DTD is a maximum entropy tensor-variate normal distribution whose tensor random variables are constrained to be positive definite to ensure their physicality. In each voxel, the second-order mean and fourth-order covariance tensors of the DTD are estimated using a Monte Carlo method that synthesizes micro-diffusion tensors with corresponding size, shape, and orientation distributions to best fit the measured MDE images. From these tensors we obtain the spectrum of diffusion tensor ellipsoid sizes and shapes, and the microscopic orientation distribution function (μODF) and microscopic fractional anisotropy (μFA) that disentangle the underlying heterogeneity within a voxel. Using the DTD-derived μODF, we introduce a new method to perform fiber tractography capable of resolving complex fiber configurations. The results revealed microscopic anisotropy in various gray and white matter regions and skewed MD distributions in cerebellar gray matter not observed previously. DTD MRI tractography captured complex white matter fiber organization consistent with known anatomy. DTD MRI also resolved some degeneracies associated with diffusion tensor imaging (DTI) and elucidated the source of diffusion heterogeneity which may help improve the diagnosis of various neurological diseases and disorders.

Tuning flow-through cu-based hollow fiber gas-diffusion electrode for high-efficiency carbon monoxide (CO) electroreduction to C2+products

Electrochemical carbon monoxide reduction (CORR) to C2+ products has advantages over electrochemical CO2 conversion (CO2RR) as issues such as carbonation, and CO2 loss during CO2RR are omitted in CORR due to the stability of CO in alkaline solutions. Facing common challenges as CO2RR, CORR suffers more from mass transport resistance and intrinsically lower aqueous CO solubility. Therefore gas-diffusion electrodes (GDEs) are desired to boost the formation of triple phases and active sites to obtain higher reaction rates. Herein, for the first time Cu-based hollow fiber GDEs (HFGDEs) are tuned for CORR to C2+ products. By growing a layer of Cu nanocubes as the catalyst layer on HFGDEs, non-selective pristine copper HFGDE became highly selective for C2+ products (FE>90%), with ethylene as the main product (FE>65%), owing to the dominant Cu (100) facet in Cu nanocubes with high C2+ selectivity. In addition, ultra-high ethylene partial current density of > 470 mA cm−2 at − 0.8 V vs. RHE in 5.0 M KOH was obtained, owing to the abundant porosity and surface area available for triple-phase formation on microtubular GDEs and their enhanced mass transport. The electrodes exhibited one of the highest partial current densities achieved for ethylene production, indicating the promises of flow-through hollow fiber configuration for other desired products or gas-phase electrochemical reactions with low aqueous solubility.

High power noise-like pulse at 2 μm and its applications in mid-IR Raman light and flat supercontinuum

Herein, a high-power noise-like (NL) pulse fiber laser system in the 2 μm region and its applications in mid-IR Raman stokes light and flat supercontinuum (SC) were experimentally demonstrated. An all-PM fiber configuration oscillator was constructed as the seed source which can deliver stable NL mode-locked pulse trains centered at ∼1950 nm wavelength with ∼5.37 MHz repetition rate. The pulse envelope and coherence spike widths of the NL pulse can be tunable from ∼2.5 ns to ∼3.4 ns and ∼397 fs to ∼375 fs, respectively. Relying on the magnified NL pulse, the cascaded Raman shifted stokes lights centered at ∼2148 nm and ∼2359 nm were separately achieved. Meanwhile, a flat SC with a 10 dB bandwidth of ∼480 nm (from ∼1940 nm to ∼2420 nm) was obtained after boosting in a large-mode-area fiber amplifier stage, and the average output power of ∼72 W represents the highest output power of the NL pulse in the 2 μm region, to the best of our knowledge. Moreover, we noted that the NL pulse-based spectrum broadening is much more effective than that the picosecond pulse-based. Our experimental results strongly imply that the NL pulse can be severed as an ideal laser source for the application of mid-IR spectroscopy.

LIGHT-TRANSMITTING CONCRETE PROPERTIES OF SHORT WALL PANEL

Consideration of fiber configuration and the distance between the light source or light meter and the LTC specimen in the previous studies is still limited. The incorporation of plastic optical fiber (POF) into concrete with fiber configurations of 5 ´ 5 and 6 ´ 6 grids is investigated in terms of short wall panel application to study its light intensity and strength properties. The light-transmitting concrete (LTC) short wall panel of 300 mm wide ´ 400 mm high ´ 75 mm thick is cast using self-compacting concrete (SCC) to ensure the flowability of the concrete during mixing. The fresh SCC is tested under slump flow, V-funnel, and L-box to verify its fresh properties, while compression test is carried out at 28-days on cube specimens to determine its compressive strength. Then, light transmittance and axial load test under compression are conducted for the LTC wall panel. The findings show that the light intensity of the LTC wall panel increased with the increased number of fiber configurations. However, regardless of fiber configurations, the light intensity reduced with the increase of both light source and light meter distances. In addition, the ultimate axial load of the LTC wall panel with fiber configurations of 5 ´ 5 and 6 ´ 6 grids are 662 kN and 643 kN, respectively. It implies that the fiber configuration does not affect the axial compression load. Furthermore, both LTC wall panels failed solely under pure compression load.

The impact of specimen size and alteration of fiber configuration on the flexural performance of high-performance concrete

This study examines the impact of fiber configuration and specimen size on the flexural performance and thus the energy absorption capacity of moderate and high-performance fiber reinforced concrete (FRC). A total of 180 specimens were produced using hooked-end steel fibers in lengths of 30-mm and 60-mm, and 54-mm long macro synthetic fibers. The specimens, in the form of small beams (75 × 75 × 320 mm3), large beams (150 × 150 × 750 mm3), and square panel specimens (600 × 600 × 100 mm3), were tested in accordance with EN14488-5 and ASTM C1609 standards. The results showed that as the amount of fibers increased, the flexural performance of FRC improved significantly, provided that precautions were taken to avoid mixing and placement issues when using higher amounts of fibers. 60-mm hooked-end steel fibers had the best performance among all the fibers tested with higher ultimate and post-cracking flexural strengths. 54-mm synthetic fibers seemed to be a cost-effective alternative with comparable energy absorption performance when compared to 30-mm hooked-end steel fibers. Small beams had a slightly higher ultimate (∼15% more) and post-cracking (∼35% more) flexural strengths than large beams, but the equivalent flexural strength ratio was not significantly affected by the specimen size. No clear relationship between fiber dosage and ultimate flexural strength was observed, but a relationship was observed between the fiber dosage and the equivalent flexural strength ratio, with R2 values ranging from 65% to 93% depending on the concrete matrix and the fiber type. The study also showed strong correlations (R2>91%) between the energy absorption capacity of plate specimens and beam specimens, suggesting that plate specimens can be used to reduce the time and effort required in testing during trial batches and product development. Finally, the use of high-performance concrete does not seem to be necessary, when the target is to improve the energy absorption capacity of FRC, particularly at low fiber volumes.