Reconstruction of Ovine Trachea with a Biomimetic Composite Biomaterial

The aim of this study was to evaluate a novel composite material for tracheal reconstruction in an ovine model. A polymer containing various forms of carbon fibers (roving, woven, and nonwoven fabric) impregnated with polysulfone (PSU) was used to create cylindrical tracheal implants, 3 cm in length and 2.5 cm in diameter. Each implant, reinforced with five rings made of PSU-impregnated carbon-fiber roving, had three external layers made of carbon-fiber woven fabric and the inner layer formed of carbon-fiber nonwoven fabric. The inner surface of five implants was additionally coated with polyurethane (PU), to promote migration of respiratory epithelium. The implants were used to repair tracheal defects (involving four tracheal rings) in 10 sheep (9-12 months of age; 40-50 kg body weight). Macroscopic and microscopic characteristics of the implants and tracheal anastomoses were examined 4 and 24 weeks after implantation. At the end of the follow-up period, outer surfaces of the implants were covered with the tissue which to various degree resembled histological structure of normal tracheal wall. In turn, inner surfaces of the prostheses were covered only with vascularized connective tissue. Inner polyurethane coating did not improve the outcomes of tracheal reconstruction and promoted excessive granulation, which contributed to moderate to severe stenosis at the tracheal anastomoses. The hereby presented preliminary findings constitute a valuable source of data for future research on a tracheal implant being optimally adjusted for medical needs.

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Pitch-based carbon fiber reinforced cements: structure, performance, applications, and research needs

Canadian Journal of Civil Engineering ◽

10.1139/l92-003 ◽

1992 ◽

Vol 19 (1) ◽

pp. 26-38 ◽

Cited By ~ 10

Author(s):

Nemkumar Banthia

Keyword(s):

Carbon Fiber ◽

Physical Properties ◽

Mechanical Behavior ◽

Key Words ◽

Carbon Fibers ◽

Fiber Reinforcement ◽

Performance Characteristics ◽

Future Research ◽

Cement Composites ◽

Research Needs

The improvements in the performance characteristics of cements due to carbon fiber reinforcement are described. In particular, the structure, the physical properties, the mechanical behavior, and the durability aspects of carbon–cement composites using pitch-based fibers are discussed. The various possible applications of these composites in structural and nonstructural applications are enumerated. The future research needs are identified. Key words: cements, carbon fibers, microstructure, strength, toughness, durability, applications.

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Current overview of carbon fiber: Toward green sustainable raw materials

BioResources ◽

10.15376/biores.15.3.xu ◽

2020 ◽

Vol 15 (3) ◽

pp. 7234-7259

Author(s):

Yongjian Xu ◽

Yan Liu ◽

Shenglin Chen ◽

Yonghao Ni

Keyword(s):

Carbon Fiber ◽

Carbon Fibers ◽

Melt Spinning ◽

Raw Materials ◽

Future Research ◽

Process Conditions ◽

Preparation Methods ◽

Advantages And Disadvantages ◽

Solution Spinning ◽

And Performance

Lignin, as a potential precursor of carbon fiber, has the characteristics of abundant reserves, renewable and high carbon content, and its application in the preparation of carbon fibers has substantial cost advantages if some important processing and quality hurdles can be overcome. This paper reviews the preparation process of lignin-based carbon fibers, and moreover, describes the characteristics of carbon fiber prepared by different precursors compared with the presently used precursors. Three preparation methods for lignin-based carbon fibers are introduced: melt spinning, solution spinning, and electrospinning. The applicability, advantages, and disadvantages of the three preparation methods are analyzed from the aspects of process conditions and performance characteristics. Possible directions for future research are considered, with the goal of providing a reference for further study of lignin-based carbon fibers.

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An investigation into self-sensing property of hat-shaped 3D orthogonal woven composite under bending test

Journal of Reinforced Plastics and Composites ◽

10.1177/0731684418808093 ◽

2018 ◽

Vol 38 (4) ◽

pp. 149-166 ◽

Cited By ~ 1

Author(s):

Xiaoying Cheng ◽

Hongshui Zhou ◽

Zhenyu Wu ◽

Xudong Hu

Keyword(s):

Carbon Fiber ◽

Carbon Fibers ◽

Sensor Arrays ◽

Woven Fabric ◽

Bending Test ◽

Fiber Array ◽

Reinforced Composite ◽

Resistance Variation ◽

Deformation Distribution ◽

3D Orthogonal Woven

In this paper, the influence of damage and deformation on the electrical property of carbon fibers in the hat-shaped 3D orthogonal woven fabric-reinforced composite structure is studied. A method of producing parallel sensor arrays was proposed, in which the warp yarns made of carbon fibers were separated by isolated Kevlar fibers as weft yarns and Z-yarns. The sensor array unitized the self-sensing property of carbon fiber and could detect the damage and deformation distribution along the transverse direction of the composite under bending tests. Both the experiments and simulations had been conducted to analyze the mechanical and electrical responses of the carbon fiber array. By comparing the experimental results and simulation data, the method was validated and the influences of damage and deformation distribution on the resistance variation of carbon fibers were revealed.

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Image Processing Algorithm for Calculating Uniformity of Carbon Surface Image Heating Element

International Journal of Engineering & Technology ◽

10.14419/ijet.v7i3.34.19378 ◽

2018 ◽

Vol 7 (3.34) ◽

pp. 547

Author(s):

Hyung Soo Hwang ◽

Joon Ho Cho

Keyword(s):

Image Processing ◽

Carbon Fiber ◽

Carbon Fibers ◽

Nonwoven Fabric ◽

Heating Element ◽

Carbon Surface ◽

Image Processing Algorithm ◽

Manufacturing Method ◽

Nonwoven Fabrics ◽

Numerical Calculation Method

Background/Objectives: In this paper, numerical calculation method using image processing technology for percentage and uniformity of carbon fibers of planar heating element was proposed.Methods/Statistical analysis: The manufacturing method of the planar heating element is made by chopping the carbon fiber in small size and bonding it again via the dispersing agent. Filter the carbon fiber solution bound using a dispersant on the next nonwoven fabric. The last step is to obtain planar carbon fibers in the form of nonwoven fabrics for drying the filtered carbon fibers.Findings: n the planar heating element, electricity may be applied to the carbon fiber on the surface produced in this manner. Calculation of the ratio and uniformity of the planar heating element in this paper addressed four sample images (0.2 wt.%, 0.4 wt.%, 0.8 wt.%, 2.4 wt.%). In this method, the image of the planar heating element was divided into 5 × 5, converted into a binary image, and then the ratio and uniformity were numerically calculated.Improvements/Applications: The image analysis of the planar heating element proposed in this paper can be interpreted more accurately by combining it with the conventional method.

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Integration of rCF in resin transfer pressing process

Journal of Reinforced Plastics and Composites ◽

10.1177/0731684420906879 ◽

2020 ◽

Vol 39 (9-10) ◽

pp. 361-372

Author(s):

C Goergen ◽

D May ◽

P Mitschang

Keyword(s):

Carbon Fiber ◽

Carbon Fibers ◽

Nonwoven Fabric ◽

Stacking Sequence ◽

Composite Manufacturing ◽

Saturation Degree ◽

Nonwoven Fabrics ◽

Thermoset Resin ◽

Pressing Process

A new composite manufacturing process, resin transfer pressing, is introduced in this paper. In this process, nonwoven fabrics made of recycled carbon fibers are oversaturated with thermoset resin, i.e. they contain excess resin. The oversaturated nonwoven fabrics are prefabricated and used as resin carrier in a press process, where they are placed in a heated mold together with a dry textile-based preform. During pressing, the resin is pressed out and transferred from the nonwoven into the non-impregnated preform and hence impregnates the whole reinforcement. This study examines the oversaturation of nonwoven fabrics, the resin transfer pressing laminate manufacturing and the surface quality of the laminates. The ability of a nonwoven fabric to be oversaturated with resin is defined by the saturation degree, which was determined as up to 12 for glass fiber nonwoven fabrics and up to 60 for recycled carbon fiber nonwoven fabrics. Different laminates are manufactured by resin transfer pressing, and the impregnation quality is evaluated. With an optimized stacking sequence, a pore content <1% was achieved. The use of recycled carbon fiber nonwovens in the resin transfer pressing process leads to a less wavy surface compared to a wet compression molding manufactured laminate, showing a decrease of waviness Wz25 of 11% minimum.

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A Digital Twin Approach to a Quantitative Microstructure-Property Study of Carbon Fibers through HRTEM Characterization and Multiscale FEA

Materials ◽

10.3390/ma13194231 ◽

2020 ◽

Vol 13 (19) ◽

pp. 4231

Author(s):

Rebekah Sweat ◽

Jin Gyu Park ◽

Richard Liang

Keyword(s):

Carbon Fiber ◽

Carbon Fibers ◽

Focused Ion Beam ◽

Ion Beam ◽

Scale Model ◽

X Ray ◽

Digital Twin ◽

X Ray Scattering ◽

Forms Of Carbon ◽

Ray Scattering

Microstructures of typical carbon fibers (CFs) from polyacrylonitrile (PAN) and pitch-based precursors were studied using a novel digital twin approach with individual carbon fibers for a local crystal scale model. The transmission electron microscopy (TEM) samples were prepared using a focused-ion beam (FIB) for both longitudinal and transverse directions of carbon fibers. Measurements of the crystal size and orientation were estimated from X-ray scattering. TEM imaging of graphitic packing facilitated further comprehension of associations between processing and final material properties, which could enable customization of microstructures for property targets. Then the detailed microstructural information and their X-ray scattering properties were incorporated into the simulation model of an individual carbon fiber. Assuming that graphene properties are the same among different forms of carbon fiber, a reasonable physics-based explanation for such a drastic decrease in strength is the dislocations between the graphitic units. The model reveals critical defects and uncertainty of carbon fiber microstructures, including skin/core alignment differences and propagating fracture before ultimate failure. The models are the first to quantify microstructures at the crystal scale with micromechanics and to estimate tensile and compressive mechanical properties of carbon fiber materials, as well as potentially develop new fundamental understandings for tailoring carbon fiber and composites properties.

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A new method of grafting multi-walled carbon nanotubes on carbon fibers for improving the mechanical and thermal properties of woven fabric composites

Journal of Composite Materials ◽

10.1177/0021998321991615 ◽

2021 ◽

pp. 002199832199161

Author(s):

Mingrui Liu ◽

Qiong Rao ◽

Yingyu Wang ◽

Xiongqi Peng

Keyword(s):

Mechanical Properties ◽

Carbon Nanotubes ◽

Carbon Fiber ◽

Carbon Fibers ◽

Acid Treatment ◽

Woven Fabrics ◽

Woven Fabric ◽

Carboxyl Groups ◽

Multi Walled Carbon Nanotubes ◽

Walled Carbon Nanotubes

A new method of grafting multi-walled carbon nanotubes (MWCNTs) onto carbon fiber surface to improve the thermo-mechanical properties of woven carbon fabric reinforced composites was proposed. In this method, both carbon woven fabrics and MWCNTs were oxidized by sulfuric acid to generate carboxyl groups on their surfaces, respectively. Then silane coupling agent was used to react with the carboxyl groups to graft MWCNTs onto the carbon fiber surfaces of the woven fabric. The untreated, acid treated and MWCNTs grafted carbon woven fabrics were separately combined with polypropylene films to form composite plates by thermal-stamping. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy were conducted to estimate the changes of element contents and functional groups on surfaces of carbon fibers and MWCNTs. Atomic force microscope was used to estimate the roughness of carbon fiber surfaces. Scanning electron microscopy, differential scanning calorimeter, dynamic mechanical thermal analysis and tensile tests were carried out to analyze the surface morphology, thermal, and mechanical properties of carbon fabrics and their composites. Testing results showed that MWCNTs could be successfully grafted onto the carbon fibers by using silane as an intermediate bridge. Compared with the untreated and acid treated composites, the in-plane shearing stiffness and fracture strength of the composites were increased significantly by MWCNTs grafting. In terms of thermal properties, acid treatment and MWCNTs grafting have little effect on melting point of composites. MWCNTs can promote the recrystallization process of the PP and reduce the numbers of imperfect crystals. As for thermo-mechanical properties, acid treatment deteriorated the bending storage modulus of the composite, while MWCNTs grafting could compensate it.

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A Pilot Study of Mobile Telephone Message Interventions with Suicide Attempters in China

Crisis ◽

10.1027/0227-5910/a000017 ◽

2010 ◽

Vol 31 (2) ◽

pp. 109-112 ◽

Cited By ~ 35

Author(s):

Hui Chen ◽

Brian L. Mishara ◽

Xiao Xian Liu

Keyword(s):

Pilot Study ◽

Effective Means ◽

Text Message ◽

Text Messages ◽

Mobile Telephone ◽

Future Research ◽

Quick Method ◽

Suicide Attempters ◽

To Receive

Background: In China, where follow-up with hospitalized attempters is generally lacking, there is a great need for inexpensive and effective means of maintaining contact and decreasing recidivism. Aims: Our objective was to test whether mobile telephone message contacts after discharge would be feasible and acceptable to suicide attempters in China. Methods: Fifteen participants were recruited from suicide attempters seen in the Emergency Department in Wuhan, China, to participate in a pilot study to receive mobile telephone messages after discharge. All participants have access to a mobile telephone, and there is no charge for the user to receive text messages. Results: Most participants (12) considered the text message contacts an acceptable and useful form of help and would like to continue to receive them for a longer period of time. Conclusions: This suggests that, as a low-cost and quick method of intervention in areas where more intensive follow-up is not practical or available, telephone messages contacts are accessible, feasible, and acceptable to suicide attempters. We hope that this will inspire future research on regular and long-term message interventions to prevent recidivism in suicide attempters.

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Post Discharge Clinically Overt Venous Thromboembolism in Orthopaedic Surgery Patients with Negative Venography -an Overview Analysis

Thrombosis and Haemostasis ◽

10.1055/s-0038-1650681 ◽

1996 ◽

Vol 76 (06) ◽

pp. 0887-0892 ◽

Cited By ~ 32

Author(s):

Serena Ricotta ◽

Alfonso lorio ◽

Pasquale Parise ◽

Giuseppe G Nenci ◽

Giancarlo Agnelli

Keyword(s):

Venous Thromboembolism ◽

Orthopaedic Surgery ◽

Diagnostic Methods ◽

Future Research ◽

Post Discharge ◽

Pharmacological Prophylaxis ◽

Vein Thrombosis ◽

Overview Analysis ◽

Major Orthopaedic Surgery

SummaryA high incidence of post-discharge venous thromboembolism in orthopaedic surgery patients has been recently reported drawing further attention to the unresolved issue of the optimal duration of the pharmacological prophylaxis. We performed an overview analysis in order to evaluate the incidence of late occurring clinically overt venous thromboembolism in major orthopaedic surgery patients discharged from the hospital with a negative venography and without further pharmacological prophylaxis. We selected the studies published from January 1974 to December 1995 on the prophylaxis of venous thromboembolism after major orthopaedic surgery fulfilling the following criteria: 1) adoption of pharmacological prophylaxis, 2) performing of a bilateral venography before discharge, 3) interruption of pharmacological prophylaxis at discharge in patients with negative venography, and 4) post-discharge follow-up of the patients for at least four weeks. Out of 31 identified studies, 13 fulfilled the overview criteria. The total number of evaluated patients was 4120. An adequate venography was obtained in 3469 patients (84.1%). In the 2361 patients with negative venography (68.1%), 30 episodes of symptomatic venous thromboembolism after hospital discharge were reported with a resulting cumulative incidence of 1.27% (95% C.I. 0.82-1.72) and a weighted mean incidence of 1.52% (95% C.I. 1.05-1.95). Six cases of pulmonary embolism were reported. Our overview showed a low incidence of clinically overt venous thromboembolism at follow-up in major orthopaedic surgery patients discharged with negative venography. Extending pharmacological prophylaxis in these patients does not appear to be justified. Venous thrombi leading to hospital re-admission are likely to be present but asymptomatic at the time of discharge. Future research should be directed toward improving the accuracy of non invasive diagnostic methods in order to replace venography in the screening of asymptomatic post-operative deep vein thrombosis.

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Cytocompatibility of Carbon Nanofiber Materials for Neural Applications

MRS Proceedings ◽

10.1557/proc-774-o7.35 ◽

2003 ◽

Vol 774 ◽

Author(s):

Janice L. McKenzie ◽

Michael C. Waid ◽

Riyi Shi ◽

Thomas J. Webster

Keyword(s):

Carbon Fiber ◽

Surface Energy ◽

Carbon Nanofibers ◽

Carbon Fibers ◽

Carbon Nanofiber ◽

Fiber Composite ◽

Scar Tissue ◽

Pc 12 Cells ◽

Low Surface Energy ◽

Poly Carbonate

AbstractSince the cytocompatibility of carbon nanofibers with respect to neural applications remains largely uninvestigated, the objective of the present in vitro study was to determine cytocompatibility properties of formulations containing carbon nanofibers. Carbon fiber substrates were prepared from four different types of carbon fibers, two with nanoscale diameters (nanophase, or less than or equal to 100 nm) and two with conventional diameters (or greater than 200 nm). Within these two categories, both a high and a low surface energy fiber were investigated and tested. Astrocytes (glial scar tissue-forming cells) and pheochromocytoma cells (PC-12; neuronal-like cells) were seeded separately onto the substrates. Results provided the first evidence that astrocytes preferentially adhered on the carbon fiber that had the largest diameter and the lowest surface energy. PC-12 cells exhibited the most neurites on the carbon fiber with nanodimensions and low surface energy. These results may indicate that PC-12 cells prefer nanoscale carbon fibers while astrocytes prefer conventional scale fibers. A composite was formed from poly-carbonate urethane and the 60 nm carbon fiber. Composite substrates were thus formed using different weight percentages of this fiber in the polymer matrix. Increased astrocyte adherence and PC-12 neurite density corresponded to decreasing amounts of the carbon nanofibers in the poly-carbonate urethane matrices. Controlling carbon fiber diameter may be an approach for increasing implant contact with neurons and decreasing scar tissue formation.

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