Distribution Of Fibers Research Articles

Numerical assessment of fiber distribution effects on strain-hardening cement composites using a rate-dependent Voronoi-Cell-Lattice-Model

Strain-hardening cementitious composites, also known as high-performance fiber-reinforced cementitious composites, display exceptional strength and toughness not only under static conditions but also under high-speed dynamic loading. The mechanical properties of these composites are greatly influenced by the orientation and dispersion of embedded fibers. However, experimental analysis of complex fiber arrangements in real specimens has limitations, necessitating the development of computational models to understand the impact of fiber distribution. This study examines the effect of fiber distribution conditions on composite behavior using a Voronoi-Cell-Lattice-Model that incorporates reinforcing effects into discrete-type quasi-brittle matrix elements. Firstly, virtual fiber distribution models revealed that as the gauge length of specimens increased, weaknesses in fiber distribution were more likely to form, leading to decreased strength and strain capacity. Secondly, the model demonstrated that favorable fiber orientation relative to the loading direction and minimal sectional deviation in fiber dispersion significantly increased strain capacity and toughness. Finally, the study explored the wall-effect that may arise during specimen fabrication due to the boundary of the casting mold.

Fracture properties of green nano fibrous network with random and aligned fiber distribution: A hierarchical molecular dynamics and peridynamics approach

Polylactic acid (PLA) nanofibrous networks have gained substantial interest across various engineering and scientific disciplines, such as tissue engineering, drug delivery, and filtration, due to their unique and multifunctional attributes, including biodegradability, tuneable mechanical properties, and surface functionality. However, predicting their mechanical behaviour remains challenging due to their structural complexity, multiscale features, and variability in material properties.This study presents a hierarchical approach to investigate the fracture phenomena in both aligned and randomly oriented nanofibrous networks by integrating atomistic modelling and non-local continuum mechanics, peridynamics. At the nanoscale, all-atom molecular dynamics simulations are employed to apply tensile loads to freestanding pristine and silver-doped PLA nanofibres, where key mechanical properties such as Young's modulus, Poisson's ratio, and critical energy release rate are determined using innovative approaches. A new method is introduced to seamlessly transfer data from molecular dynamics to peridynamics by ensuring the convergence of the tensile response of a single fiber in both frameworks. This nano to micro coupling technique is then utilised to examine the Young's modulus, fracture toughness of mode I and II, and crack propagation in PLA nanofibrous networks. The proposed framework can also incorporate the effects of surface coating and fiber arrangements on the measured properties. The current research paves the way for the development of stronger and more durable eco-friendly nanofibrous networks with optimised performance.

Effects of coarse aggregates on 3D printability and mechanical properties of ultra high performance fiber reinforced concrete

3D printing of ultra high performance fiber reinforced concrete (UHPFRC) suffers from high shrinkage and poor interlayer properties. To mitigate these problems, this study develops new mixtures of UHPFRC materials containing coarse aggregates (CA), and critically examines their suitability for 3D printing (3DP). Totally 90 mould-cast and 3DP cylinder and beam specimens with different CA sizes (5–15 mm) and CA-binder ratios (0.3–0.5) were tested under compression and bending in three directions. The internal distribution and volume fractions of steel fibers and pores and the crack trajectories were characterized and analysed by micro X-ray CT scanned 3D images with 37 μm voxel resolution. The results show that adding more and bigger CAs into UHPFRC reduced the flowability but enhanced the buildability with desired extrudability achieved by adjusting 3D printing velocity. Although the compressive strength of the 3DP cylinders was 15–42 % lower than that of the mould-cast ones due to higher porosities, over 100 MPa strength was still achieved for all the 3DP cylinders with less than 10 % anisotropy. The CT images did not show evident interlayers and interlayer delamination under compression, indicating the new 3DP mixtures and printing parameters may have highly promoted cement hydration. The flexural strength of 3DP beams was 3–34 % higher than that of the cast ones, because most fibres were oriented in the printing or beam axis direction as represented by overall orientation indices calculated from CT images, thereby providing significant crack-bridging effects. The developed new mixtures are therefore well suited for 3D printing, particularly for fabrication of structural members with preferred fibre orientation, such as beams, slabs and shells.

Interaction of multiple micro-defects on the strength and failure mechanism of UD composites by computational micromechanics

The mechanical properties of unidirectional fiber-reinforced plastic (UD-FRP) are affected by a variety of micro-defects, such as random fiber arrangement, fiber misalignment and micro-voids. This study aims to investigate how these multiple micro-defects interact with each other and how they affect the strength and failure mechanism of UD-FRP by means of computational micromechanics. The composite behavior was simulated by the finite element analysis of a representative volume element of the composite microstructure in which the random distribution of fibers, the micro-voids, and the fiber misalignment are explicitly included. Both matrix and interface failure were considered for the loadings of transverse tension/compression, longitudinal compression, transverse/longitudinal shear, and their combination. It was found that these three micro-defects significantly weakened the compressive strength of UD-FRP along the longitudinal direction. Especially, the fiber misalignment magnified the effect of fiber arrangement, while the micro-voids reduce the effect. Besides, the fiber arrangement and micro-voids significantly weakened the tensile and compressive strength of UD-FRP along the transverse direction, but their interaction effect was not obvious. Moreover, transverse and longitudinal shear strength are significantly affected by micro-voids, but only longitudinal shear is affected by geometric fiber arrangement, and this effect is also weakened by micro-voids. Finally, the damage envelope under the combined longitudinal compression and transverse loads was obtained and compared with the Tsai-Wu failure criterion. The results showed that the Tsai-Wu criteria can provide an effective estimation for the failure locus under this biaxial loading condition.

Fabrication of tetra‐n‐butylammonium hydrogen sulfate‐based poly(lactic acid)‐poly(ethylene glycol) composite electrospun wound dressing

AbstractIn this study, poly(lactic acid)‐poly(ethylene glycol)‐tetra‐n‐butylammonium hydrogen sulfate (PLA‐PEG‐HS) electrospun mats were fabricated by electrospinning as effective wound dressings against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), which are the most prevalent species of gram‐positive and gram‐negative bacteria, respectively. PLA is a polymer with high biocompatibility and biodegradability, but its structure is fragile. Therefore, we aimed to improve its structural properties using PEG as a plasticizer and to provide antibacterial properties with HS salt. The nanofibers characterized using differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy, thermal gravimetric analysis (TGA), and drying time tests. The addition of HS eliminated the beads in the PLA‐PEG nanofiber and improved the homogeneity of the fiber distribution. Concerning this result, when the liquid absorption capacity (LAC) test was evaluated, PLA‐PEG‐HS nanofiber production was achieved with the highest rate of 480.95%. The thermal properties of nanofibers increased with the addition of HS. Cytotoxicity test results of PLA‐PEG‐HS wound dressings showed high cell viability of 129.05% in L292 mouse fibroblast cells at the end of the 24th hour. PLA‐PEG‐HS nanofibers with 99.99% antibacterial activity against tow bacteria. Considering the modern wound dressing requirements, antibacterial wound dressing production has been successfully achieved.

Dynamic tensile properties of straw fiber reinforced rubber concrete

Rubber concrete (RC) has received a great deal of attention in the field of construction materials, owing to its outstanding mechanical properties and potential for waste recycling. Despite extensive research on the mechanical behavior of RC, there remains a notable gap in understanding the dynamic characteristics of fiber reinforced rubber concrete. This study specifically focuses on the dynamic characteristics of RC with straw fibers as reinforcement. The investigative methodologies employed scanning electron microscope (SEM) analysis, computed tomography (CT) scans, and split Hopkinson pressure bar (SHPB) with a high-speed camera system for dynamic tension tests. The CT experimental findings reveal a uniform distribution of rubber particles and straw fibers within the concrete matrix. The dynamic tensile strength of straw fiber reinforced rubber concrete (SFRC) demonstrates a linear correlation with increasing loading rates. The results showed that SFRC-1.5 had 4.8 % lower static strength and 15 % lower dynamic strength than RC without straw fibers at the load rate of 110 GPa/s. In terms of energy, the dissipated energy density increased by 5.36 % at this loading rate. In addition, at a straw content of 2.5 %, the initial cracking time reached a maximum value of 220 μs. The highest level of shear resistance was observed at this content. This study emphasizes the heightened capability of SFRC under dynamic loading forces, thereby contributing to its potential application in green civil engineering and other related fields.

A design method for continuous fiber-reinforced composite patches

The urgent need for lightweight and high-strength patches in the field of aircraft structural repair has propelled continuous fiber-reinforced thermoset composites into a research hotspot. However, constrained by manufacturing processes, the designs of composite repair structures primarily focus on external shape and ply layup. These approaches presently lack design methods for the internal fiber adaptability of patches driven by in-service loads. In this paper, we proposed a method for fiber distribution and orientation design based on maximum normal stress. The composite simulation model was established based on fracture toughness. The influence of tensile-shear coupling effects on the mechanical response of composites and the fiber orientation design were examined in the study. The orientation-density coupling effects on the enhancement of patch strength were also analyzed. Furthermore, additive manufacturing technology was employed to fabricate thermoset composite patches. The results show that the composite patches designed in this paper exhibit a 10.50 % improvement in strength compared to traditional unidirectional patches.

Bundle-specific tractogram distribution estimation using higher-order streamline differential equation

Streamline tractography locally traces peak directions extracted from fiber orientation distribution (FOD) functions, lacking global information about the trend of the whole fiber bundle. Therefore, it is prone to producing erroneous tracks while missing true positive connections. In this work, we propose a new bundle-specific tractography (BST) method based on a bundle-specific tractogram distribution (BTD) function, which directly reconstructs the fiber trajectory from the start region to the termination region by incorporating the global information in the fiber bundle mask. A unified framework for any higher-order streamline differential equation is presented to describe the fiber bundles with disjoint streamlines defined based on the diffusion vectorial field. At the global level, the tractography process is simplified as the estimation of BTD coefficients by minimizing the energy optimization model, and is used to characterize the relations between BTD and diffusion tensor vector under the prior guidance by introducing the tractogram bundle information to provide anatomic priors. Experiments are performed on simulated Hough, Sine, Circle data, ISMRM 2015 Tractography Challenge data, FiberCup data, and in vivo data from the Human Connectome Project (HCP) for qualitative and quantitative evaluation. Results demonstrate that our approach reconstructs complex fiber geometry more accurately. BTD reduces the error deviation and accumulation at the local level and shows better results in reconstructing long-range, twisting, and large fanning tracts.

Microstructural characteristics and mechanical properties of 3D printed Kevlar fibre reinforced Onyx composite

Abstract The main objective of this study is to develop the Kevlar fibre reinforced Onyx composite (KFRO) material by employing the 3D printing technology and examine the effect of Kevlar fibre reinforcement percentage on microstructural characteristics and mechanical properties of developed composite material. The methodology of continuous fibre reinforced composites (CFRC) was followed and the Kevlar fibre reinforcement % was varied as 10 %, 20 % and 30 % in the composite material fabrication. Results disclosed that the KFRO composite 3D printed using 30 % Kevlar fibre reinforcement in Onyx matrix yielded greater tensile strength of 124 MPa, flexural strength of 105 MPa, impact toughness of 2.4 J and shore hardness of 76 D. The mechanical properties of KFRO composite were significantly improved at 20 % of Kevlar fibre reinforcement compared to 10 % of Kevlar fibre reinforcement. Further increase in Kevlar fibre reinforcement up to 30 % showed slight enhancement in mechanical properties of KFRO composite when compared to 20 % of Kevlar fibre reinforcement. The overall strength improvement is a result of the increased reinforcement, precise alignment of fibres in the loading direction, and the uniform distribution of fibres within the onyx.

Understanding the Structure-Function Relationship through 3D Imaging and Biomechanical Analysis: A Novel Methodological Approach Applied to Anterior Cruciate Ligaments.

Understanding the microstructure of fibrous tissues, like ligaments, is crucial due to their nonlinear stress-strain behavior from unique fiber arrangements. This study introduces a new method to analyze the relationship between the microstructure and function of anterior cruciate ligaments (ACL). We tested the procedure on two ACL samples, one from a healthy individual and one from an osteoarthritis patient, using a custom tensioning device within a micro-CT scanner. The samples were stretched and scanned at various strain levels (namely 0%, 1%, 2%, 3%, 4%, 6%, 8%) to observe the effects of mechanical stress on the microstructure. The micro-CT images were processed to identify and map fibers, assessing their orientations and volume fractions. A probabilistic mathematical model was then proposed to relate the geometric and structural characteristics of the ACL to its mechanical properties, considering fiber orientation and thickness. Our feasibility test indicated differences in mechanical behavior, fiber orientation, and volume distribution between ligaments of different origins. These indicative results align with existing literature, validating the proposed methodology. However, further research is needed to confirm these preliminary observations. Overall, our comprehensive methodology shows promise for improving ACL diagnosis and treatment and for guiding the creation of tissue-engineered grafts that mimic the natural properties and microstructure of healthy tissue, thereby enhancing integration and performance in biomedical applications.

Functional description of fiber orientation in paperboard based on orientation tensors resulting from μ-CT scans

Modern μ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\upmu$$\\end{document}-CT scans offer non-destructive three-dimensional microstructure analysis of various materials. Despite small density contrasts, this technology also accurately captures the complex network structure of paper and paperboard. It provides detailed insight into the fiber orientation distribution in paper, which was previously unattainable with existing measurement methods. The image analysis results are applicable for numerical fiber network models, and simulations based on these models can significantly improve our understanding of the microstructural influence on macrostructural paper properties, such as strength, stiffness, and curl tendency. This work presents a new method for investigating the microstructural fiber orientation in paperboard. Orientation tensors obtained from μ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\upmu$$\\end{document}-CT scan image processing are extracted and evaluated. Based on the direction of the orientation tensor’s first eigenvector, the fiber orientation distribution is determined and then approximated by periodic and non-periodic probability density functions (PDFs). In this study, 40 commercial paperboard samples, each consisting of three plies, were analyzed. From a given set of commonly used PDFs, the best fitting ones have been identified based on their original location in the paper roll and on their ply. It was found that the von Mises PDF provided the most accurate representation of fiber orientation distribution in the middle ply, while the Elliptical PDF was the most suitable for the outer plies. Moreover, a more pronounced fiber orientation anisotropy was observed at the edges of the paper roll than in its center. The best PDFs and their function parameters are provided to allow for direct usage in numerical microstructure models of paperboard, thus enhancing their representativeness.

A Compendium of Research, Tools, Structural Analysis, and Design for Bamboo Structures

Bamboo is known for its ability to grow at a high speed, with strong sustainability indicators and remarkable strength properties. However, despite these qualities, the practice of designing bamboo structures is still in its early stages in many regions. This paper aims to review the current approaches to structural analysis and design for bamboo structures as found in the existing literature. Through this comprehensive review, this study seeks to identify existing research gaps and areas that require further exploration. The limited design philosophy for bamboo structures can be attributed to the scarcity of studies on the characteristics and mechanics of bamboo material. These findings highlight the necessity for more comprehensive guidelines and standards to enhance the structural analysis and design of bamboo structures. This study identifies gaps in the following areas: lack of consideration for bamboo fiber distribution, lack of guidelines for load parameters specific to bamboo structures, inadequate coverage of bamboo culm connections, inadequate coverage on connection stiffness, limited scope on connection types, and species-specific limitations in standards.

Diffusion model predicts the geometry of actin cytoskeleton from cell morphology.

Cells exhibit various morphological characteristics due to their physiological activities, and changes in cell morphology are inherently accompanied by the assembly and disassembly of the actin cytoskeleton. Stress fibers are a prominent component of the actin-based intracellular structure and are highly involved in numerous physiological processes, e.g., mechanotransduction and maintenance of cell morphology. Although it is widely accepted that variations in cell morphology interact with the distribution and localization of stress fibers, it remains unclear if there are underlying geometric principles between the cell morphology and actin cytoskeleton. Here, we present a machine learning system that uses the diffusion model to convert the cell shape to the distribution and alignment of stress fibers. By training with corresponding cell shape and stress fibers datasets, our system learns the conversion to generate the stress fiber images from its corresponding cell shape. The predicted stress fiber distribution agrees well with the experimental data. With this conversion relation, our system allows for performing virtual experiments that provide a visual map showing the probability of stress fiber distribution from the virtual cell shape. Our system potentially provides a powerful approach to seek further hidden geometric principles regarding how the configuration of subcellular structures is determined by the boundary of the cell structure; for example, we found that the stress fibers of cells with small aspect ratios tend to localize at the cell edge while cells with large aspect ratios have homogenous distributions.

Investigation on anisotropic toughness and cracking behavior of woven lay-up Fiber Metal Laminates with two-level customized interfaces

Interlaminar toughening for metal-polymer interfaces in woven lay-up Fiber Metal Laminates (w-FMLs) is a critical concern, demanding isotropic mechanics and higher energy dissipation. Customizing interfaces with interlocking structures like dimples or grooves has proven effective in meeting these requirements, while the resulting two-level features introduce greater complexity in toughening effects, and interfacial mechanics are influenced by factors such as fiber orientation and resin distribution. To understand the anisotropy effect and toughening mechanics induced by different two-level features, three types of two-level customized interfaces of w-FMLs are examined. Edge shear tests are utilized to evaluate interfacial mechanics and toughness, with a focus on tracing crack propagation behaviors. Through numerical simulation and characterization, the toughening effect and its mechanisms are unveiled, revealing that differences in toughness pinning effect and local plastic deformation of the customized interfaces are the primary determinants of interlaminar toughness. Additionally, a coupling effect between the woven core and interfaces is observed, showing that the superposition of the tougher orientation of the woven core on the strong toughness pinning orientation of the interfaces is a crucial factor in determining excellent overall interlaminar toughness.

Schematic construction of carbon fiber tow microstructure models and their effect on tensile strength of carbon fiber tow/epoxy composites: Quantification of carbon fiber distribution, misalignment, and interlacing

Carbon fiber reinforced polymers (CFRPs) are increasingly being used in cutting-edge technologies, thus rendering accurate material characterization essential. However, the unexpected microstructures of carbon fiber (CF) tows, such as random fiber distribution, misalignment, and interlacing, degrade the mechanical properties of CFRPs and render them unpredictable. Hence, the microstructures of CF tows and their effect on the performance of CFRPs must be investigated.Herein, we propose a framework for quantifying the microstructural parameters of three types of T700 grade CF tows and investigate their effects on the tensile strengths of CF tows and CF tow-reinforced composites. CF cross sections are analyzed via microscopy to measure the fiber distribution and misalignment with respect to the location. A two-roll mill experiment is designed to evaluate fiber interlacing by compressing the CF tow in the thickness direction. The tensile strengths of CFs, CF tows, and CF tow-reinforced composites are measured, whereas their interfacial shear strengths are obtained via a micro-droplet test.Two CF tow microstructure models are proposed: the uniform distribution model with a low degree of fiber misalignment resulted in a higher tensile strength ratio of CF tow compared to the core-shell model, as well as a higher tensile strength of CF tow/epoxy composites. Results indicate that the microstructure of the CF tow significantly affects the properties of the composite materials. Therefore, utilizing the framework proposed herein as a tow design parameter is expected to fulfill the varying requirements of important properties in composite material design based on the application field.

Effect of Process Parameters on the Appearance of Defects of Flake-Pigmented Metallic Polymer.

This study investigates the influence of the main process parameters of injection molding(mold temperature, melt temperature, and injection rate) on the appearance of defects of flake-pigmented metallic polymer parts. To understand the influence of process parameters, an appearance defects index (ADI) is proposed to quantify the appearance defects. In this process, we propose a criterion for judging the appearance of defects based on the results of fiber orientation and tensor distribution analyses of the skin layer, which is then verified analytically by simulating experiments from the literature. Using the Taguchi experimental method, we designed an L25 orthogonal array to systematically evaluate the influence of process parameters. For each experimental condition, the signal-to-noise ratio (S/N ratio) was calculated to determine the optimal level of each factor and its influence on the appearance of defects. According to the results, mold temperature has the greatest influence on the appearance of defects, with an influence of 48.7%, followed by injection rate with an influence of 40.8%, and melt temperature with an influence of 10.5%. The optimal process parameters were found to be a mold temperature of 40 °C, a melt temperature of 250 °C, and an injection rate of 10 cm3/s, which resulted in a 12.6% improvement in the Appearance defects index (ADI) compared to the standard injection molding condition of ABS materials. This study confirmed that it is possible to improve the appearance of defects by adjusting the process parameters of injection molding.

Fibre-reinforced geopolymer (FRG) cemented aeolian sand flexural properties and microproduct evolutionary processes

To reveal the flexural behaviour and microproduct evolution mechanism of FRG cemented aeolian sand, four factors, namely, sodium hydroxide dosage, water-solid ratio, fibre dosage, and fibre length, were classified into mutually independent levels and combined to form a set of test matrices for the design of orthogonal tests. Using DIC digital scattering technology to analyze the evolutionary process of specimen ring-breaking and employing scanning electron microscopy to explore the polymerization product micro-morphology, evolutionary process, pore defects, and analyze the fiber endowment morphology and the destruction mode; the use of EDS spectroscopy, X-ray diffraction, Fourier IR spectroscopy, and other technical means to analyze the polymerization product chemical composition, elemental distribution, and evolutionary characteristics. The results of the study show that the 28-day flexural performance of FRG cemented wind-blown sand as a filling material is significantly affected by various factors in the following order of magnitude: sodium hydroxide dosage > water-solid ratio > fibre dosage > fibre length. The optimal combination from the local test is: sodium hydroxide dosage of 1.4 %, the water-solid ratio of 0.32, the fibre dosage of 0.5 %, and the fibre length of 12 mm. With the increase in load, the value of the displacement field increases continuously, indicating a greater degree of specimen damage. As the reaction proceeds, the polymerization product's morphology evolves from rod-like to flaky, ultimately stabilizing into a network structure. The main elements in the product include C, O, Si, Al, and Ca, indicating that the polymerization product is a C-(A)-S-H gel. A reasonable distribution of discrete ductile fibers can play a positive role inside the specimen, acting as a bridge. The damage behavior under bridging can be divided into fiber debonding, producing slippage behavior, and fiber damage, leading to fracture behavior. The results of the study provide a scientific basis for the design, preparation, and application of solid waste filling materials, thereby promoting the development of materials science and engineering.

Composite Pressure Vessel Failure Simulation Considering Spatial Variability

Carbon fiber-reinforced polymers offer lightweight solutions for demanding applications, but material imperfections affect structural reliability. In this study, an efficient uncertainty propagation framework is applied to predict composite behavior. The framework accounts for spatial variability of fiber misalignment, uneven fiber distribution, and single-fiber strength. Spatial variability is represented at both the micro- and mesoscale. Macroscale simulations incorporate this spatial variability indirectly using homogenized material properties. The framework was applied to composite pressure vessels, whose stochastic burst pressure was predicted. The predictions were validated by experimental measurements. These measurements show that the actual burst pressure was underpredicted by an average of 5.8%. Several hypotheses were investigated to explain this discrepancy.

Research Progress on the Regulating Factors of Muscle Fiber Heterogeneity in Livestock: A Review.

The type of muscle fiber plays a crucial role in the growth, development, and dynamic plasticity of animals' skeletal muscle. Additionally, it is a primary determinant of the quality of both fresh and processed meat. Therefore, understanding the regulatory factors that contribute to muscle fibers' heterogeneity is of paramount importance. Recent advances in sequencing and omics technologies have enabled comprehensive cross-verification of research on the factors affecting the types of muscle fiber across multiple levels, including the genome, transcriptome, proteome, and metabolome. These advancements have facilitated deeper exploration into the related biological questions. This review focused on the impact of individual characteristics, feeding patterns, and genetic regulation on the proportion and interconversion of different muscle fibers. The findings indicated that individual characteristics and feeding patterns significantly influence the type of muscle fiber, which can effectively enhance the type and distribution of muscle fibers in livestock. Furthermore, non-coding RNA, genes and signaling pathways between complicated regulatory mechanisms and interactions have a certain degree of impact on muscle fibers' heterogeneity. This, in turn, changes muscle fiber profile in living animals through genetic selection or environmental factors, and has the potential to modulate the quality of fresh meat. Collectively, we briefly reviewed the structure of skeletal muscle tissue and then attempted to review the inevitable connection between the quality of fresh meat and the type of muscle fiber, with particular attention to potential events involved in regulating muscle fibers' heterogeneity.

Quantum key distribution in optical fibers: a comprehensive design view of the overall quantum layer beyond transmission

This paper reports the network operator point of view about the introduction of quantum key distribution (QKD) in optical networks to secure the data plane and/or specific applications, focusing on the design aspects that go beyond pure transmission. The functional architecture of a quantum key distribution network is depicted focusing on the integration in the existing telecommunications infrastructure. Some use cases of the utilization of the QKD layer, presenting results from in-field demonstrations, are reported together with a technology agnostic numerical model about resource sharing in a metropolitan area network environment.