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Chong-wen Yu – 1st expert on this subject based on the ideXlab platform
Simulating the motion of a flexible fiber in 3D tangentially injected swirling airflow in a straight pipe—Effects of some parametersInternational Journal of Heat and Mass Transfer, 2020Co-Authors: Bingang Xu, Chong-wen Yu, Sheng-yan LiAbstract:
A numerical model for particle-level simulation of fiber suspensions has been used to simulate fiber dynamics in three-dimensional tangentially injected swirling airflow in Air-Jet Spinning nozzles. The fiber is modeled as chains of beads connected through massless rods, and its flexibility is defined by the bending and twisting displacements. The effects of some parameters, such as fiber initial position, the injection angle and the injector diameter on fiber motion and yarn properties are discussed. The springy, snake-like and week helical regimes of fiber motion are observed under the most cases. The far from the tube center the fiber release position, the smaller the fiber flexibility is. For a smaller injection angle, the self-entanglement regimes of fiber motion are observed in the downstream of the injectors. The model also predicted the complex helical configuration in the nozzle with a small injector diameter. The predictions of yarn properties coincide with the experimental results reported by several researchers.Institute of Textiles and Clothin
3D tangentially injected swirling recirculating flow in a nozzle with a slotted‐tube—Effects of groove parametersInternational Journal for Numerical Methods in Fluids, 2020Co-Authors: Zhiyong Chen, Chong-wen YuAbstract:
A numerical prediction for 3D swirling recirculating flow in an Air-Jet Spinning nozzle with a slotted-tube is carried out with the realizable k-e turbulence model. The effects of the groove parameters on the flow and yarn properties are investigated. The simulation results show that some factors, such as reverse flow upstream of the injector, vortex breakdown downstream of the injector, comer recirculation zone (CRZ) behind the step and vortex ring in the groove caused by the groove geometric variation, are significantly related to fluid flow, and consequently to yarn properties. With increasing groove height, the length of the CRZ increases, while the initial vortex ring in the groove decreases and a same direction rotating vortex forms in the bottom of the groove. Similarly, as the groove width increases, the extent of both vortex breakdown in downstream of the injectors and the vortex ring in the groove increases slightly, whereas the CRZ lengths in stream-wise direction decrease. Some factors, such as the negative tangential velocities, the size of the vortex rings in the grooves and the CRZ, are constant for nozzles with different groove lengths.
Dynamics of the Ramie Yarn Hair in the Nozzle of the JetWind Process and Effects of Some Nozzle ParametersJournal of Natural Fibers, 2015Co-Authors: Ge Chen, Chong-wen YuAbstract:
The technique of reducing yarn hairiness using an Air-Jet nozzle on the winder (JetWind) is a combination of the ring and Air-Jet Spinning technologies. The dynamics of the hair inside the nozzle plays an important role in the JetWind process. In this study, a dynamical model for the coupling between a protruding surface hair on the ramie yarn and the airflow in the JetWind process is developed. Based on the model, numerical simulation of the dynamics of the hair in the nozzle is performed and the principle of reducing yarn hairiness is theoretically shown. The simulation result is validated by the experimentally captured motional configurations of the hair in the nozzle using high-speed photography technique. The effects of two nozzle parameters—the injector angle and yarn passage diameter on the dynamics of the hair and in turn, yarn hairiness are investigated by both numerical simulation and experiments.
Abdalla Abdal-hay – 2nd expert on this subject based on the ideXlab platform
Engineering of electrically-conductive poly(ε-caprolactone)/ multi-walled carbon nanotubes composite nanofibers for tissue engineering applicationsCeramics International, 2019Co-Authors: Abdalla Abdal-hay, Mohamed Taha, Hamouda M. Mousa, Michal Bartnikowski, Mohammad L. Hassan, Montasser Dewidar, Saso IvanovskiAbstract:
In this communication, air jet Spinning (AJS)was used to successfully fabricate nanofibers of poly (e-caprolactone)(PCL)onto which Multi-Walled Carbon Nanotubes (MWCNTs)were loaded at 0.5 to 1.0 wt % using a cost-effective fabrication technique. SEM images indicated that the incorporation of MWCNTs resulted in the production of larger fiber sizes with a more uniform size distribution than plain PCL. TEM observation showed the MWCNTs were parallel and oriented along the axes of the nanofibers. Specific interfacial interactions between the PCL and the MWCNTs enhanced the mechanical properties of the nanofibers in terms of tensile modulus and tensile strength. The electrical conductivity improved at the higher (1.0%)MWCNT concentration, alongside improved hydrophilicity, demonstrated through decreases in contact angle measurements. Moreover, in vitro studies with human bone osteosarcoma cells (Saos-2)revealed that MWCNT scaffolds displayed desired cell attachment and spreading. These high performance MWCNT-PCL nanocomposite fiber mats have been demonstrated as good candidates for modern microelectronics and tissue engineering applications.
Rapid fabrication of highly porous and biocompatible composite textile tubular scaffold for vascular tissue engineeringEuropean Polymer Journal, 2017Co-Authors: Abdalla Abdal-hay, Yi Seul Oh, Adnan Memic, Kamal Hany Hussein, Mohamed Fouad, Fawzi F. Al-jassir, Yosry Morsi, Xiumei Mo, Saso IvanovskiAbstract:
Abstract Three dimensional (3D) constructs for vascular tissue engineering applications require scaffolds with highly porous architectures, high biocompatibility and mechanical stability. In this paper, composite fibrous tubular scaffolds composed of different ratios of poly(epsilon-caprolactone) (PCL) and polyamide-6 (PA-6) were simultaneously deposited layer by layer by employing the air jet Spinning (AJS) textile technique. Specifically, we report on the optimal parameters for the fabrication of composite porous scaffolds that allow for precise control over the general scaffold architecture, as well as the physical and mechanical properties of the scaffolds. In vitro cell culture study was performed to investigate the influence of polymer composition and scaffold architecture on the adhesion of EA.hy926 human endothelial cells onto the fabricated scaffolds. The cell culture results indicated that a composite scaffold with low PA-6 fibrous content is the most promising substrate for EA.hy926 adhesion and proliferation. Based on the present findings, these highly porous composite tubular constructs support endothelial cell migration and cellular infiltration, and hence represent promising nano-fibrous scaffolds for vascular tissue engineering.
Biocorrosion behavior of biodegradable nanocomposite fibers coated layer-by-layer on AM50 magnesium implant.Materials Science and Engineering: C, 2015Co-Authors: Abdalla Abdal-hay, Abdel Salam Hamdy, Anwarul Hasan, Yu-kyoung, Khalil Abdelrazek KhalilAbstract:
This article demonstrates the use of hybrid nanofibers to improve the biodegradation rate and biocompatibility of AM50 magnesium alloy. Biodegradable hybrid membrane fiber layers containing nano-hydroxyapatite (nHA) particles and poly(lactide)(PLA) nanofibers were coated layer-by-layer (LbL) on AM50 coupons using a facile single-step air jet Spinning (AJS) approach. The corrosion performance of coated and uncoated coupon samples was investigated by means of electrochemical measurements. The results showed that the AJS 3D membrane fiber layers, particularly the hybrid membrane layers containing a small amount of nHA (3 wt.%), induce a higher biocorrosion resistance and effectively decrease the initial degradation rate compared with the neat AM50 coupon samples. The adhesion strength improved highly due to the presence of nHA particles in the AJS layer. Furthermore, the long biodegradation rates of AM50 alloy in Hank’s balanced salt solution (HBSS) were significantly controlled by the AJS-coatings. The results showed a higher cytocompatibility for AJS-coatings compared to that for neat Mg alloys. The nanostructured nHA embedded hybrid PLA nanofiber coating can therefore be a suitable coating material for Mg alloy as a potential material for biodegradable metallic orthopedic implants.
Jae Kyoo Lim – 3rd expert on this subject based on the ideXlab platform
In vitro deposition of Ca-P nanoparticles on air jet Spinning Nylon 6 nanofibers scaffold for bone tissue engineeringApplied Surface Science, 2014Co-Authors: Abdalla Abdal-hay, Yi Seul Oh, Ayman Yousef, Hem Raj Pant, Pablo Vanegas, Jae Kyoo LimAbstract:
Microporous, non-woven nylon 6 (N6) scaffolds were prepared with an air jet Spinning (AJS) approach. In this process, polymer fibers with diameters down to the nanometer range (nanofibers) were formed by subjecting a fluid jet to high pressure air. The effects of the solution conditions on the morphological appearance and average diameter of the as-spun N6 fibers and crystal structure were investigated. The morphological properties of the AJS membrane mats could easily be tailored by adjusting the concentration of the polymer solution. Solutions at high concentrations were necessary to form well-defined fibers without beads. The production rate (viz. solvent evaporation rate) had the greatest effect on the chain structure conformation of N6. The predominant structure phase of the N6 fibers fabricated by AJS was a thermodynamically stable α-form while the electroSpinning fibers induced the metastable γ-form. AJS significantly enhanced the mechanical properties of the N6 mat. The bone formation ability of AJS fibers was evaluated by incubating the fibers in biomimetic simulated body fluid for 5 and 10 days at 37 °C. Overall, the new AJS approach developed for membrane structures has great potential for the fabrication of hard and soft tissue engineering scaffolds. © 2014 Elsevier B.V. All rights reserved.