Horizontal Fibers Research Articles

Experimental and numerical investigation on shear behavior of concrete beams reinforced with CFRP grid shear reinforcements

This research investigated the shear behavior of concrete beams reinforced with Carbon Fiber Reinforced Polymer (CFRP) bars and grids as longitudinal reinforcements and stirrups, in experiment and finite element (FE) methods. Five concrete beams were tested under a monotonical load and experienced shear failure as expected. The test variables including stirrup ratio and grid dimension were considered to investigate the interaction between grid and concrete, and the influence between the horizontal and vertical fibers of the grid. It found that reducing the grid dimension with the constant stirrup ratio could effectively improve the stress distribution of the grid and the shear capacity of the beam. The grid dimension greatly determined the shear capacity of specimens when the stirrup ratio changed in a small range. The horizontal fibers of the grid had anchoring effects on the vertical fibers and directly carried the tensile stress from concrete at the top and bottom of the beam. In FE analysis, the fiber composite layer was adopted to simulate the CFRP grid. The load-midspan deflection of specimens and strain development of the grid in the FE model showed good agreement with the tests. In parameter analysis, the grid configuration with the horizontal fiber arranged in the middle or upper part of the section was recommended.

Newly revealed anatomy of the bucinator muscle: An anatomical and histological study

BackgroundCurrent anatomical knowledge of the origin of the bucinator muscle (BM), i.e., long thin attachments on the maxilla and mandible and the pterygomandibular raphe (PMR), is not supported by anatomical dissection of this muscle. The aim of this study was therefore to investigate the detailed morphology of the BM and associated structures and to discuss its function. MethodsThe anatomy of the BM and related structures was investigated in 15 cadaveric heads using a surgical microscope and histological analysis. ResultsThe inferior fibers of the BM originated from a small retromolar area (internal oblique line), which shared a common tendon with the deep tendon of the temporalis. The superior fibers of the BM originated from the maxillary tuberosity. The middle fibers originated the pterygoid hamulus. No PMR was identified in any of the specimens, but the border between the BM and superior pharyngeal constrictor muscle (SC) was clear because the muscle fibers followed different directions. Some horizontal fibers were continuous between the BM and SC. ConclusionsOur results suggest the need to revise established accounts of the origins of the bucinator (the maxillary tuberosity, conjoint tendon of the temporalis, and pterygoid hamulus without a pterygomandibular raphe. It also needs to be noted that some of its fibers merge directly with the SC.

Near real-time nautical depth mapping via horizontal optical fibers and distributed acoustic sensing

Safe navigation in ports and waterways subjected to siltation requires nautical depth monitoring. For this purpose, surveying vessels equipped with a zero-offset echo sounder and intrusive point measurements are frequently used. Because these measurements depend on the availability of a surveying vessel and require access to quay walls, such as at the container terminals in seaports, the temporal resolution is limited. Especially at these locations, a high temporal resolution monitoring system could allow for a higher occupancy rate. We propose to use Distributed Acoustic Sensing to monitor the nautical depth using fiber-optical cables. We install five horizontal fibers at different heights between two points and continuously record along the complete installation. Analysing the continuous recordings, we show that horizontal fibers can be used to monitor the water-mud interface depth with a vertical resolution around six mm. Multiple passive sources, like vessel movements and water currents, are used to estimate the water-mud interface.

Lipschitz classification of Bedford-McMullen carpets with locally uniform horizontal fibers

It is well known that the Hausdorff dimension and box dimension of a Bedford-McMullen carpet coincide if and only if the carpet has uniform horizontal fibers. Yang et al. [17] gave a complete Lipschitz classification of such carpets which are totally disconnected and possessing vacant rows. In this paper, we show that if we replace the uniform horizontal fibers condition by a locally uniform horizontal fibers condition, the conclusions of Yang et al. still hold.

Fracture Height Quantification from Vertical and Horizontal Section Fiber Measurements: A Comprehensive Study Using LF-DAS Measurements from HFTS-2 Data Set

Summary Understanding fracture height growth is critical for optimizing hydraulic fracture treatments and field development. In recent years, low-frequency distributed acoustic sensing (LF-DAS) has become a popular tool for monitoring strain changes during hydraulic fracturing. While LF-DAS data from vertical monitoring wells (VMWs) can be used to determine fracture height, measurements from the vertical section of horizontal wells may have the potential to capture fracture height growth. The objectives of this study are (1) to apply three methods—(a) using the vertical section of horizontal fiber measurements, (b) using the vertical fiber measurements, and (c) using the horizontal section of horizontal fiber measurements—to determine the fracture height using the Hydraulic Fracturing Test Site 2 (HFTS-2) data set and (2) to demonstrate the reliability of using LF-DAS measurements from the vertical section of horizontal fibers for fracture height determination. In an effort to determine the fracture height from the HFTS-2 data set using the three methods, we demonstrate the reliability of the height prediction using strain measurements in the vertical section of the horizontal monitoring well (VS-HMW). First, we analyze the measurements from the vertical section of the horizontal fiber (B3H) during the stimulation of the heel-most stages of the horizontal wells (B1H, B2H, and B4H). Second, we analyze the measurements from the VMW (B5PH) during the stimulations of B1H, B2H, and B4H. Third, we use a geomechanical inversion algorithm to obtain height estimates from the horizontal section of the LF-DAS measurements at B3H during B1H, B2H, and B4H stimulations. The fracture height is determined based on the transition of the extension-compression zone in the LF-DAS measurements from the vertical sections. The height estimates obtained using the three methods are compared and found to be consistent in the six well pairs we analyzed. The LF-DAS measurements from the vertical well B5PH provide a complete height profile, while measurements from the vertical section capture fracture growth from the upper tip of the fracture to the landing depth of the horizontal well. The fracture height estimates obtained from our inversion algorithm represent the average height value of all fracture hits at the chosen stage. This study demonstrates the potential to determine fracture height growth using LF-DAS measurements in the vertical section of a horizontal well, thus avoiding the cost associated with drilling VMWs to obtain fracture heights.

Effect of velocity on compression and energy absorption sensitivity of coir fiber

Coir fiber, a natural plant fiber material, is known for its excellent shock absorption ability and potential to improve the performance of composite materials. This paper investigates the compression and energy absorption of coir fibers arranged horizontally and vertically at different speeds to determine their velocity sensitivity. A quasi-static compression speed test was conducted on coir fiber blocks using a universal testing machine. Load displacement changes were observed at speeds of 1 mm/Min, 2 mm/Min, 4 mm/Min, and 50 mm/Min, and Dynamic Increase Factor (DIF) was introduced to evaluate speed sensitivity. The microstructure of the fibers was evaluated using a scanning electron microscope (SEM). According to the results, vertical fibers have better energy absorption characteristics than horizontal fibers, resulting in an increased energy absorption effect ranging from 25.7 % to 45.38 %. On the other hand, horizontal fibers exhibit high sensitivity under low-speed compression, with a significant increase in energy-absorbing effect as speed increases. However, this sensitivity is significantly reduced when compression occurs at high speed. The energy-absorbing effect of horizontal fibers increases from 6.96 % to 33.58 %. Vertically placed fibers, on the other hand, exhibit low sensitivity under low-speed compression but greater sensitivity as speed increases. As speed increases, the energy absorption effect becomes more apparent, resulting in an increase in the energy absorption of vertical fibers from 12.88 % to 17.99 %. This paper presents a methodology for evaluating the compression properties of coir fibers, which can be used as a reference for studying the impact resistance of natural fibers.

Microstructures and electrical conductivity properties of compressed gas diffusion layers using X-ray tomography

Bulk resistance of the gas diffusion layer (GDL) plays an important role in the ohmic loss of proton exchange membrane fuel cells (PEMFCs). This work represents the first direct experimental study and comparison of the bulk resistances during the compression process of commonly used commercial GDLs, carbon paper and carbon felt, from the perspective of the microstructure mechanisms. The in-situ X-ray tomography and a fiber tracing algorithm are used to obtain the microstructure characteristics of compressed GDLs. The through-plane (T-P) and in-plane (I-P) bulk resistances of GDLs are measured by the microelectrode probe measurement method and the four-point probe method, respectively. Then, their resistivities are calculated. For the T-P direction, the arrangement of fibers gradually becomes compact during the compression, arousing the nearly linear increase of fiber contact points. Thus, more and more conductive paths are constructed, inducing a rapid decline of the T-P bulk resistivity. Since the fibers in carbon felt are entangled together, the fibers in the edge areas are arranged loosely at low compression. This uneven distribution of contact points in carbon felt results in much larger T-P bulk resistivity than that of carbon paper at low compressive strain. For carbon paper, binders contribute significantly to the smaller T-P resistivity because they tend to gather at the fiber intersections, which forms more conductive paths with better conductivity. For the I-P direction, the bulk resistivities of GDLs decrease linearly during compression. The nearly horizontal fibers are the key to the I-P bulk resistivity, and both smaller fiber density and higher fiber tortuosity lead to the increase of the I-P bulk resistivity. This study helps to understand the microstructure mechanisms of the bulk resistances of various GDLs during the compression process, which can guide the design and fabrication process of GDLs.

Liquid flow behavior in the concentric mesh packing with novel fiber cross-sectional shape in a rotating packed bed

Mesh packing has been widely exploited in rotating packed beds (RPBs). Fiber cross-sectional shape (CSS) of mesh has exhibited significant influence on liquid flow behavior. The concentric mesh packing outperforms conventional coiled mesh packing in mass transfer. However, in-depth insights into liquid flow characteristics in concentric mesh packing, especially with novel fiber CSS, which is indispensable for mass transfer modelling, are scarce. Herein, the liquid flow behavior in concentric mesh packing composed of vertical quadrangular fibers and horizontal elliptical fibers (VQHE) and the packing composed of circular fibers (VCHC) were investigated via high-speed photography technology in an RPB. Typical liquid flow patterns and their transition in packings were illuminated. The liquid film covered wider regions in VQHE than that in VCHC. The transition criteria for flow patterns has been proposed. The VQHE reduced the average droplet diameter by 19%, enhanced the uniformity of droplet size distribution, and decreased average droplet velocity by 15%, compared to VCHC. Furthermore, correlations to predict the average droplet diameter and velocity were developed with deviations of ±15% and ±20%, respectively.

Major change in morphology of the talofibular ligaments during fetal development and growth.

Ankle sprain is often attributed to damage of theanterior and posterior talofibular ligaments (ATFL, PTFL). We compared the morphology of these ligaments in fetuses of different gestational ages (GAs) with the horizontal configuration in adults. Histological sections of unilateral ankles were examined in22 fetuses, 10 at GA of 9-12weeks and 12 at GA of 26-39weeks. At a GA of 9 to 10weeks,theATFL and PTFL consisted of horizontally running straight fibers. The initial ATFL appeared as a thickening of the capsule of the talocrural joint, although the initial PTFL was distant from this joint. Until a GA of 12weeks, the talus and fibula were separated by an expanding joint cavity. Thus, the initial horizontal ligaments were "pulled" in a distal direction. The distal parts of the ligaments consisted of thin collagenous fibers that had an irregular array, whereas the short proximal parts had thick fibers and a horizontal array. In near-term fetuses, the ligaments contained no horizontal fibers. The ATFL had a wavy course around the thick synovial fold, and was exposed to the joint cavity along the entire course; the distal part was thinner than the proximal part.The PTFLwas bulky and consisted of fibers with an irregular array. Therefore, the morphology in a near-term fetus was quite different from that in adults. The horizontal and straight composite ankle fibers in adults apparently result from postnatal reconstruction, depending on mechanical demand.

TWO NEW SPECIES OF STILLABOTHRIUM (CESTODA: RHINEBOTHRIIDEA) FROM STINGRAYS FROM NORTHERN AUSTRALIA AND ONE NEW COMBINATION.

A study of cestode specimens that were collected during survey work on elasmobranchs collected from Taiwan and Northern Territory, Australia, revealed the presence of 1 new combination into the genus Stillabothrium (Rhinebothriidea: Escherbothriidae) and 2 new species of the genus. Phyllobothrium biacetabulatum, collected from Rhinobatos schlegelii, is transferred to Stillabothrium and its description is emended, as is the diagnosis for the genus Stillabothrium and the family Escherbothriidae. Stillabothrium biacetabulatum n. comb. differs from existing species of the genus in that the face of its bothridia is laced with a network of longitudinal and horizontal muscle fibers that do not contribute to the formation of septa. Stillabothrium lunae n. sp. is described from Himantura leoparda and differs from existing species of the genus in that its bothridium possesses an anterior field of 7-8 loculi that are wider than long. Stillabothrium mariae n. sp. is described from Maculabatis astra. This species differs from all species of Stillabothrium except Stillabothrium campbelli in possessing 10-12 horizontally oriented bothridial loculi. Stillabothrium mariae n. sp. differs from S. campbelli in having longer bothridia and from all other species of Stillabothrium in that it lacks, rather than possesses, conspicuous septa and loculi that are longer than wide in the posterior region of its bothridia. Bayesian and parsimony-bootstrap analysis of 28S rDNA revealed S. biacetabulatum n. comb., S. lunae n. sp., and S. mariae n. sp. to be part of Clade 1 of Stillabothrium, with S. biacetabulatum n. comb. being the sister species to S. mariae n. sp. Stillabothrium lunae n. sp. was found to be the sister species to Stillabothrium borneoense.

Desulfurization performance in a HiGee reactor with packing containing different fiber cross-sectional shapes

HiGee reactors have been utilized for H2S removal from offshore natural gas by chelated iron solution, which exhibits great advantages due to their compact footprint. However, the blockage of packing in HiGee reactor caused by sulfur generation can lead to a decline of desulfurization efficiency. Herein, the fiber cross-sectional shape of mesh packing was optimized for alleviating blockage based on the understanding of liquid flow behavior with various single-layer meshes in our previous studies (Wen et al., Chem. Eng. Sci. 2022, 248, 117147). The novel packing with vertical quadrangular fibers and horizontal elliptical fibers (VQHE) as well as the conventional packing with circular fibers (VCHC) were designed and fabricated by three-dimensional printing technology. A rotating packed bed (RPB) reactor with mesh packing, as one of the typical HiGee reactors, was adopted for H2S removal. Results indicate that H2S removal efficiency of VQHE could reach up to 99.3%. The mass transfer coefficient of VQHE was 25.9% higher than that of VCHC. Meanwhile, the photograph displays that less sulfur solid was deposited on the surface of VQHE. The mass increase ratio of VQHE was smaller by 24.9% than that of VCHC. VQHE realized the integration of enhancing H2S removal efficiency and alleviating blockage in RPB reactor.

Time–space–weight calibrated plastic optical fiber-based pressure sensing carpet

We demonstrate time-, space-, and weight-based calibration techniques for pressure monitoring in the low-cost plastic optical fiber (POF) sensor carpet. It is found that the POF-based pressure sensing platform has several limitations, such as output voltage variations and difference in the sensor response for horizontal and vertical fibers due to convex and concave shapes of bend. To surpass the these limitations, we have developed time-based calibration using time windowing technique to reduce the standard deviation of photodiode output voltage variations by 98%. We have also described space and weight calibration techniques based on the convex and concave shapes of fiber bend. These techniques help in improving the Landweber image reconstruction algorithm to obtain significant clarity and improvement in object pressure images. We also report an artificial intelligence-based algorithm to determine the accuracy of positioning of the load. Experimental results demonstrate that this algorithm gives a mean square error of 0.875 cm in position detection on the carpet. We discuss the potential for a compact and cost-effective pressure sensor carpet, which integrates with the living environment and the outside world.

Optimization and buckling of rupture building beams reinforced by steel fibers on the basis of adaptive improved harmony search-harmonic differential quadrature methods

The optimization and buckling analysis of the rupture beams reinforced by steel fibers are presented in this article. The structure is simulated by hyperbolic shear deformation theory (HSDT). Utilizing Harmonic differential quadrature (HDQ) method, the buckling load is calculated. Utilizing adaptive improved harmony search (AIHS) algorithm, the optimization process of the rupture beam is examined. The mentioned algorithm is improved adaptively utilizing dynamic variables. The harmony memory is corrected at first and second adjustments, respectively on the basis of dynamic bandwidth and step size randomly. The optimum conditions of the rupture beam are evaluated with various harmony existing search methods. The influences of various constants including beam length to thickness ratio, rupture parameter, steel fibers volume fraction, steel fibers orientation angle and boundary supports are shown on the buckling load. The outcomes indicate that the proposed AIHS is performed better with respect to other harmony search methods. Meanwhile, the buckling load is reduced by enhancing the rupture parameter. Furthermore, the buckling load of the rupture beam with horizontal steel fibers is better with respect to other orientation angles.

Strain to ground motion conversion of distributed acoustic sensing data for earthquake magnitude and stress drop determination

Abstract. The use of distributed acoustic sensing (DAS) presents unique advantages for earthquake monitoring compared with standard seismic networks: spatially dense measurements adapted for harsh environments and designed for remote operation. However, the ability to determine earthquake source parameters using DAS is yet to be fully established. In particular, resolving the magnitude and stress drop is a fundamental objective for seismic monitoring and earthquake early warning. To apply existing methods for source parameter estimation to DAS signals, they must first be converted from strain to ground motions. This conversion can be achieved using the waves' apparent phase velocity, which varies for different seismic phases ranging from fast body waves to slow surface and scattered waves. To facilitate this conversion and improve its reliability, an algorithm for slowness determination is presented, based on the local slant-stack transform. This approach yields a unique slowness value at each time instance of a DAS time series. The ability to convert strain-rate signals to ground accelerations is validated using simulated data and applied to several earthquakes recorded by dark fibers of three ocean-bottom telecommunication cables in the Mediterranean Sea. The conversion emphasizes fast body waves compared to slow scattered waves and ambient noise and is robust even in the presence of correlated noise and varying wave propagation directions. Good agreement is found between source parameters determined using converted DAS waveforms and on-land seismometers for both P and S wave records. The demonstrated ability to resolve source parameters using P waves on horizontal ocean-bottom fibers is key for the implementation of DAS-based earthquake early warning, which will significantly improve hazard mitigation capabilities for offshore earthquakes, including those capable of generating tsunami.

Effects of Different Fiber-Reinforced Solutions on Fracture Strength and Pattern in Endodontically Treated Molars.

To evaluate the fracture strength of endodontically treated molars filled with different composite resins with vs without fiber reinforcement. A total of 60 intact mandibular molars were selected and endodontically treated. A standardized mesio-occlusal-distal cavity was prepared with cervical margins 1 mm above the cementoenamel junction and oral and buccal walls with 1.5-mm thickness. Universal adhesive was used in all specimens in etch-and-rinse mode. Specimens were divided into four groups (n = 15 each) according to restoration technique: group CSM = adhesive overlay with hybrid ceramic; group EXP = direct restoration with short fiber-reinforced composite; group ESU = direct restoration with nanohybrid composite; and group EST = direct restoration with nanohybrid composite reinforced with horizontal bidirectional glass fibers placed over the pulpal chamber floor. After 7 days of storage in water, samples were loaded until fracture using a universal testing machine. The maximum breaking loads were recorded in Newtons, and statistical analysis was then conducted with two-way ANOVA and post hoc Tukey test. Fragments were analyzed using scanning electron microscopy. Mean fracture resistance values were: CSM = 1,428.91 ± 316.90 N; EXP = 1,874.57 ± 299.47 N; ESU = 1,557.44 ± 355.65 N; and EST = 1,870.27 ± 145.11 N. The CSM and EXP groups showed the highest strength values when compared to the other groups. The variable fiber insertion did not significantly alter the fracture resistance. The origin of the fracture was always located on the occlusal surface, mainly in the major contact loading area. The use of fiber-reinforced composite showed great improvement in fracture resistance, similar to a cuspal coverage restoration. However, only short fiber-reinforced composites showed a favorable fracture pattern. Int J Prosthodont 2023;36:603-611.

In-situ study of the fracture behavior of SiCf/SiC composite material under three-point bending

The mechanical properties and fracture behavior of a SiCf/SiC composite material were studied by in-situ three-point bending testing. The deformation and cracking behavior of SiCf/SiC composite material was captured by the equipped scanning electron microscope. The experimental results indicate that the fracture property was highly related to the microstructure of the matrix and the SiC fibres. The in-situ observation showed that the composite material exhibited complex crack initiation and propagation process under three-point bending. Vertical microcracks initiated at the root of the preset notch and propagated vertically till blocked by the horizontal fibers. Driven by the large loca stress, horizontal cracks were also found initiated adjacent to the notch root and propagated horizontally along the interface between the fibers and the matrix.

Lipschitz classification of Bedford-McMullen carpets with uniform horizontal fibers

Let Mt,v,r(n,m), 2≤m<n, be the collection of self-affine carpets with expanding matrix diag(n,m) which are totally disconnected, possessing vacant rows and with uniform horizontal fibers. In this paper, we introduce a notion of structure tree of a metric space, and thanks to this new notion, we completely characterize when two carpets in Mt,v,r(n,m) are Lipschitz equivalent.

Personalized Computational Models of Tissue-Rearrangement in the Scalp Predict the Mechanical Stress Signature of Rotation Flaps.

To elucidate the mechanics of scalp rotation flaps through 3D imaging and computational modeling. Excessive tension near a wound or sutured region can delay wound healing or trigger complications. Measuring tension in the operating room is challenging, instead, noninvasive methods to improve surgical planning are needed. Multi-view stereo allows creation of 3D patient-specific geometries based on a set of photographs. The patient-specific 3D geometry is imported into a finite element (FE) platform to perform a virtual procedure. The simulation is compared with the clinical outcome. Additional simulations quantify the effect of individual flap parameters on the resulting tension distribution. Rotation flaps for reconstruction of scalp defects following melanoma resection in 2 cases are presented. Rotation flaps were designed without preoperative FE preparation. Tension distribution over the operated region. The tension from FE shows peaks at the base and distal ends of the scalp rotation flap. The predicted geometry from the simulation aligns with postoperative photographs. Simulations exploring the flap design parameters show variation in the tension. Lower tensions were achieved when rotation was oriented with respect to skin tension lines (horizontal tissue fibers) and smaller rotation angles. Tension distribution following rotation of scalp flaps can be predicted through personalized FE simulations. Flaps can be designed to reduce tension using FE, which may greatly improve the reliability of scalp reconstruction in craniofacial surgery, critical in complex cases when scalp reconstruction is essential for coverage of hardware, implants, and/or bone graft.

Modelling Triaxial Tests on Fibre-Reinforced Sands with Different Fibre Orientations Using the Discrete Element Method

Fibre-reinforced soil has been widely applied as a composite fill material in geotechnical engineering. In this study, triaxial tests of fibre-reinforced specimens with different fibre orientations were performed employing the discrete element method. The approach enables an investigation of some significant micromechanical properties, including the contact orientation distribution, coordination number, particle displacement field, and contact sliding fraction. From the discrete element method (DEM) perspective, fibre orientation affects the contact force distributions and the load-bearing mechanism for this mixture system. More horizontal fibre particles participate in supporting the strong force chains compared with the vertical and random fibres. Fibre orientation also affects the pattern of displacement fields, which shows that horizontal fibres can limit the formation of localised shear bands. Horizontal fibres also cause the largest increase in the normal contact force acting on the fibre-sand interface and the coordination number of the sand-fibre contact type, which leads to an increase of sliding friction between fibres and the sand matrix. The majority of horizontal fibres could also produce tension during triaxial compression, leading to a more effective reinforcement. The results from this study could contribute to improving our knowledge of mechanical behaviours of sand-fibre composites.

Self-propelling droplets on fibres subject to a crosswind

In many situations in which droplets wet fibres, wind is present. Large nets are used to harvest fog transported by coastal breezes from the ocean1,2 and noxious aerosols are contained in chemical plants by driving them across fibrous filters3,4. In glass wool factories, thin fibres are subjected to airflows as they are simultaneously sprayed with resin to glue them together5,6. The control and reconfiguration of the liquid in these situations is essential. It can be set geometrically, as is the case for assemblies of non-parallel fibres6,7 or tapered cylinders8–11, but the wind itself may also be exploited for this purpose4,12,13. Here, we show that a transverse wind can induce directional motion of droplets along horizontal fibres—even upwind if the fibre is tilted—and generate strong repulsive interactions between droplets. All of these effects are interpreted as consequences of asymmetric wakes behind the liquid. A transverse wind is shown to be capable of inciting a droplet to move along a horizontal fibre due to the presence of an asymmetric wake behind the droplet. Such a perturbation can even induce repulsive interactions between droplets.