scholarly journals The influence of the stiffness of GelMA substrate on the outgrowth of PC12 cells

2019 ◽  
Vol 39 (1) ◽  
Author(s):  
Yibing Wu ◽  
Yang Xiang ◽  
Jiehua Fang ◽  
Xiaokeng Li ◽  
Zunwen Lin ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Pc12 Cells ◽  
Young's Modulus ◽  
Neurite Length ◽  
Tissue Engineering Scaffolds ◽  
Design And Optimization ◽  
Critical Range ◽  
Neuronal Outgrowth ◽  
Cell Substrate ◽  
The Matrix

Abstract Recent studies have shown the importance of cell–substrate interaction on neurone outgrowth, where the Young’s modulus of the matrix plays a crucial role on the neurite length, migration, proliferation, and morphology of neurones. In the present study, PC12 cells were selected as the representative neurone to be cultured on hydrogel substrates with different stiffness to explore the effect of substrate stiffness on the neurone outgrowth. By adjusting the concentration of gelatin methacryloyl (GelMA), the hydrogel substrates with the variation of stiffnesses (indicated by Young’s modulus) from approximately 3–180 KPa were prepared. It is found that the stiffness of GelMA substrates influences neuronal outgrowth, including cell viability, adhesion, spreading, and average neurite length. Our results show a critical range of substrate’s Young’s modulus that support PC12 outgrowth, and modulate the cell characteristics and morphology. The present study provides an insight into the relationship between the stiffness of GelMA hydrogel substrates and PC12 cell outgrowth, and helps the design and optimization of tissue engineering scaffolds for nerve regeneration.

scholarly journals Cu Precipitation Behaviors and Microscopic Mechanical Characteristics of a Novel Ultra-Low Carbon Steel

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3571
Author(s):  
Mingxue Sun ◽  
Yang Xu ◽  
Tiewei Xu
Keyword(s):  
Cooling Rate ◽  
Young’S Modulus ◽  
Vickers Hardness ◽  
Young's Modulus ◽  
Low Carbon Steel ◽  
Carbon Steels ◽  
Precipitation Strengthening ◽  
Low Carbon ◽  
Cooling Rates ◽  
The Matrix

We studied the effect of Cu addition on the hardness of ultra-low carbon steels heat treated with different cooling rates using thermal simulation techniques. The microstructural evolution, Cu precipitation behaviors, variations of Vickers hardness and nano-hardness are comparatively studied for Cu-free and Cu-bearing steels. The microstructure transforms from ferritic structure to ferritic + bainitic structure as a function of cooling rate for the two steels. Interphase precipitation occurs in association with the formation of ferritic structure at slower cooling rates of 0.05 and 0.2 °C/s. Coarsening of Cu precipitates occurs at 0.05 °C/s, leading to lower precipitation strengthening. As the cooling rate increases to 0.2 °C/s, the interphase and dispersive precipitation strengthening effects are increased by 63.9 and 50.0 MPa, respectively. Cu precipitation is partially constrained at cooling rate of 5 °C/s, resulting in poor nano-hardness and Young’s Modulus. In comparison with Cu-free steel, the peak Vickers hardness, nano-hardness and Young’s Modulus are increased by 56 HV, 0.61 GPa and 55.5 GPa at a cooling rate of 0.2 °C/s, respectively. These values are apparently higher than those of Cu-free steel, indicating that Cu addition in steels can effectively strengthen the matrix.

Fabricating high mechanical strength γ-Fe2O3 nanoparticles filled poly(vinyl alcohol) nanofiber using electrospinning process potentially for tissue engineering scaffold

2016 ◽  
Vol 32 (4) ◽  
pp. 411-428 ◽  
Author(s):  
Nor Hasrul Akhmal Ngadiman ◽  
Noordin Mohd Yusof ◽  
Ani Idris ◽  
Denni Kurniawan ◽  
Ehsan Fallahiarezoudar
Keyword(s):  
Tissue Engineering ◽  
Mechanical Strength ◽  
Young’S Modulus ◽  
Flow Rate ◽  
Vinyl Alcohol ◽  
Young's Modulus ◽  
Electrospinning Process ◽  
Poly Vinyl Alcohol ◽  
Tissue Engineering Scaffolds ◽  
Rotating Speed

The use of electrospinning has gained substantial interest in the development of tissue engineering scaffolds due to its ability to produce nanoscale fibers which can mimic the geometry of extracellular tissues. Besides geometry, mechanical property is one of the main elements to be considered when developing tissue engineering scaffolds. In this study, the electrospinning process parameter settings were varied in order to find the optimum setting which can produce electrospun nanofibrous mats with good mechanical properties. Maghemite (γ-Fe2O3) was mixed with poly(vinyl alcohol) and then electrospun to form nanofibers. The five input variable factors involved were nanoparticles content, voltage, flow rate, spinning distance, and rotating speed, while the response variable considered was Young’s modulus. The performance of electrospinning process was systematically screened and optimized using response surface methodology. This work truly demonstrated the sequential nature of designed experimentation. Additionally, the application of various designs of experiment techniques and concepts was also demonstrated. Results revealed that electrospun nanofibrous mats with maximum Young’s modulus (273.51 MPa) was obtained at optimum input settings: 9 v/v% nanoparticle content, 35 kV voltage, 2 mL/h volume flow rate, 8 cm spinning distance, and 3539 r/min of rotating speed. The model was verified successfully by performing confirmation experiments. The nanofibers characterization demonstrated that the nanoparticles were well dispersed inside the nanofibers, and it also showed that the presence of defects on the nanofibers can decrease their mechanical strength. The biocompatibility performance was also evaluated and it was proven that the presence of γ-Fe2O3 enhanced the cell viability and cell growth rate. The developed poly(vinyl alcohol)/γ-Fe2O3 electrospun nanofiber mat has a good potential for tissue engineering scaffolds.

Improvement of Young's modulus and tensile strength of polymer impregnation and pyrolysis processed SiC/SiC composite by improved continuity of matrix

2004 ◽  
Vol 19 (8) ◽  
pp. 2377-2388 ◽  
Author(s):  
S. Ochiai ◽  
H. Okuda ◽  
S. Kimura ◽  
K. Morishita ◽  
M. Tanaka ◽  
...  
Keyword(s):  
Monte Carlo Simulation ◽  
Tensile Strength ◽  
Monte Carlo ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Shear Lag ◽  
Pyrolysis Method ◽  
The Matrix ◽  
Barium Magnesium Aluminosilicate ◽  
Polymer Impregnation

Influences of the continuity of the matrix on Young's modulus and tensile strength of unidirectional SiC/SiC mini-composite prepared by the polymer impregnation and pyrolysis method were studied experimentally by observation of appearance of matrix and tensile test and analytically by a shear lag–Monte Carlo simulation. The continuity of the matrix was improved by the addition of particles such as ZrSiO4, barium magnesium aluminosilicate, and Pyrex (borosilicate glass) into the matrix. The improved continuity of the matrix led to the increase in stress carrying capacity of the matrix and therefore to the increase in Young's modulus and tensile strength of the composite. Such a correlation between the continuity of the matrix and the property of the composite was verified numerically by the shear lag–Monte Carlo simulation.

Microscopic Methods for Characterization of Selected Surface Properties of Biodegradable, Nanofibrous Tissue Engineering Scaffolds

2017 ◽  
Vol 890 ◽  
pp. 213-216 ◽  
Author(s):  
Adrian Chlanda ◽  
Ewa Kijeńska ◽  
Wojciech Święszkowski
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Force Spectroscopy ◽  
Operating Mode ◽  
Tissue Engineering Scaffolds ◽  
Force Microscopy ◽  
Atomic Force

Biodegradable polymeric fibers with nanoand submicron diameters, produced by electrospinning can be used as scaffolds in tissue engineering. It is necessary to characterize their mechanical properties especially at the nanoscale. The Force Spectroscopy is suitable atomic force microscopy mode, which allows to probe mechanical properties of the material, such as: reduced Young's modulus, deformation, adhesion, and dissipation. If combined with standard operating mode: contact or semicontact, it will also provide advanced topographical analysis. In this paper we are presenting results of Force Spectroscopy characterization of two kinds of electrospun fibers: polycaprolactone and polycaprolactone with hydroxyapatite addition. The average calculated from Johnson-Kendall-Roberts theory Young's modulus was 4 ± 1 MPa for pure polymer mesh and 20 ± 3 MPa for composite mesh.

Recycled HDPE-tetrapack composites. Isothermal crystallization, light scattering and mechanical properties

2012 ◽  
Vol 1485 ◽  
pp. 77-82 ◽  
Author(s):  
A Parada-Soria ◽  
HF Yao ◽  
B Alvarado-Tenorio ◽  
L Sanchez-Cadena ◽  
A Romo-Uribe
Keyword(s):  
Mechanical Properties ◽  
Light Scattering ◽  
Young’S Modulus ◽  
Tensile Deformation ◽  
Young's Modulus ◽  
Ultimate Tensile Stress ◽  
Uniaxial Tensile ◽  
Scanning Calorimetry ◽  
Slow Cooling ◽  
The Matrix

ABSTRACTIn this research the thermal and mechanical properties of composites based on recycled high-density polyethylene (HDPE) and recycled Tetrapak have been investigated. The matrix and filler are recovered from landfills. Multicolor HDPE mixtures, with varying concentration of tetrapack flakes, are hot pressed, as well as single color HDPE flakes. Previous studies determine that the nature of the pigment (organics vs. inorganics) strongly influence the mechanical behavior of multicolor HDPE-tetrapack composites. Thus, this research focuses on single color HDPE hot pressed plaques. The kinetics of crystallization under isothermal conditions is determined by differential scanning calorimetry (DSC). The results show that the crystallization kinetics obeys the Avrami theory, and that the Avrami exponent is 1, irrespective of the pigment in use. Small-angle light scattering is applied to investigate the internal structure of the pigmented HDPE. SALS patterns show that the samples exhibited oriented morphologies. However, after melting and slow cooling under pressure the samples exhibit an isotropic morphology. This is confirmed by polarized optical microscopy. Mechanical properties such as Young’s modulus, yield stress and ultimate tensile stress are obtained under uniaxial tensile deformation at room temperature. For the single color HDPE plaques the Young’s modulus is reduced (after melting), suggesting that the anisotropic molecular chains contribute to the higher value of Young’s modulus.

Effective Stiffness of Nano and Transformation Composite Ceramics

2007 ◽  
Vol 336-338 ◽  
pp. 2528-2531
Author(s):  
Xiao Bo Lu ◽  
Xie Quan Liu ◽  
Xin Hua Ni ◽  
Shu Qin Zhang
Keyword(s):  
Young’S Modulus ◽  
Poisson’S Ratio ◽  
Young's Modulus ◽  
Effective Stiffness ◽  
Poisson's Ratio ◽  
High Fracture Toughness ◽  
Composite Ceramics ◽  
Average Value ◽  
Volume Average ◽  
The Matrix

The composite ceramics that contains nano-fibers and transformation particles, fabricated through SHS process, is performed with high fracture toughness and high plasticity. The matrix of composite ceramics was mainly composed of fiber eutectics with nano-fibers. The transformation particles were distributed along boundaries of the fiber eutectic structures. First, Mori-Tanaka method was used to predict the stiffness of the fiber eutectic. The fiber eutectic is transverse isotropy and has five independent elastic constants. Then considering random orientation of the fiber eutectic, the Young’s modulus and Poisson’s ratio of the matrix is determined by even strain. The matrix is isotropy. Finely, assuming the transformation particles as spheres distributed in the matrix, the effective stiffness for composite ceramics was computed. When the volume fraction of fibers and particles increase, the Young’s modulus of composite ceramics decrease and are little smaller than the volume average value, the Poisson’s ratio of composite ceramics decrease and are little bigger than the volume average value.

A Numerical Method for Predicting the Young’s Modulus of Ceramic

2010 ◽  
Vol 97-101 ◽  
pp. 638-641
Author(s):  
Xin Zhu Zhou ◽  
Jian Jun Zheng
Keyword(s):  
Pore Structure ◽  
Numerical Method ◽  
Young’S Modulus ◽  
Lattice Model ◽  
Young's Modulus ◽  
Experimental Results ◽  
Reasonable Accuracy ◽  
Maximum Element ◽  
The Matrix

This paper presents a numerical method that can predict the Young’s modulus of ceramic with reasonable accuracy. By introducing periodic conditions, the distribution of pores in the matrix phase is simulated. The lattice model is then employed for the analysis of stress in the pore structure and for the determination of the maximum element length. Finally, the validity of the proposed numerical method is preliminarily verified with the experimental results obtained from the literature.

Finite Element Analysis of Cylindrical Inclusions in Polycrystalline Nickel Alloys

2018 ◽  
Vol 09 (02) ◽  
pp. 1850003
Author(s):  
E. A. Bonifaz ◽  
A. Alban ◽  
A. Czekanski
Keyword(s):  
Finite Element ◽  
Single Crystal ◽  
Young’S Modulus ◽  
Applied Load ◽  
Elastic Limit ◽  
Young's Modulus ◽  
The Matrix ◽  
Cylindrical Inclusions ◽  
The Difference ◽  
Curve Extension

Inspired by nanotubes, a 3D finite element model was developed to simulate the influence of cylindrical inclusions on the polycrystalline mechanical behavior of Nickel alloys. A dislocation based strain hardening model, constructed in the so-called Kocks–Mecking framework, is used as the main strategy for the constitutive modeling of individual bulk grains. To determine the influence of the inclusions distribution, the direction of applied load and the size of the matrix phase on the inelastic stress–strain distribution, the digital microstructure code DREAM.3D was coupled to ABAQUS[Formula: see text] finite element code through a MatLab[Formula: see text] program. Four affordable computational representative volume elements (RVEs) meshes of two different edge sizes and two different inclusion distributions were tested to investigate the relation between micro and macro deformation and stress variables. The virtual specimens, subjected to continuous monotonic strain loading conditions, were constrained with random periodic boundary conditions. The difference in crystallographic orientation, which evolves in the process of straining, and the incompatibility of deformation between neighboring grains were accounted for by the introduction of single crystal averaged Taylor factors, single crystal Young’s modulus, single phase elastic modulus and the evolution of geometrically necessary dislocation density. The effects of single crystal Young’s modulus, inclusion distribution and direction of the applied load upon the aggregate local response are clearly observed. Results demonstrate a strong dependence of flow stress and plastic strain on phase type, Young’s modulus values and direction of the applied load, but slightly on matrix grain size. The stress–strain curve extension and the variation in the elastic limit of the individual inclusions depend on the inclusion-matrix Young’s modulus difference and applied load direction. The difference in curve extension and the difference in elastic limit decrease as the Young’s modulus of the single crystal inclusion approach the Young’s modulus of the matrix majoritary phase, while the resistance to flow increases when the applied load is perpendicular to the inclusion longitudinal axis.

Interfacial Effect on Mechanical Properties of Polypropylene Ternary Nanocomposites

2018 ◽  
Vol 913 ◽  
pp. 564-570 ◽  
Author(s):  
Wei Wang ◽  
Wei Wang ◽  
Dong Lv ◽  
Jing Shen Wu
Keyword(s):  
Mechanical Properties ◽  
Yield Stress ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Vital Role ◽  
Enhancement Effect ◽  
Weak Interface ◽  
The Matrix ◽  
Grafted Nanoparticles ◽  
The Impact

The matrix/filler interface plays a vital role in mechanical properties of polypropylene (PP)/rigid nanoparticles composites. In general, the use of spherical stearic acid modified CaCO3 (SA-CaCO3) can induce a weak interfacewhich facilitatesparticle debonding from the matrix under loading and reduces plastic resistance, enhancing the toughness of nanocomposites, while the use of polymer-grafted nanoparticles (PGS) can improve the Young’s modulus and yield stress because of strong interfacial binding between particle and matrix. With the objective to simultaneously improve the modulus, yield stress and toughness, the ternary nanocomposites, PP/PGS/CaCO3 (PPSC), were prepared and the morphology, crystallization, and mechanical behavior were investigated and compared to their binary nanocomposites. The results show that Young’s modulus is enhanced as the particle loading, and the yield stress is balanced by two interactions, i.e. the decreasing effect of the weak interface and the enhancement effect of the strong interface. The impact strength of the ternary nanocomposites shows insignificant improvement compared with neat PP, which is attributed to the brittle effect of the weak interface in the particle cluster of SA-CaCO3 and PGS.

Numerical Investigation of the Overall Stiffness of Carbon Nanotube-Based Composite Materials

2011 ◽  
Vol 13 ◽  
pp. 47-59 ◽  
Author(s):  
Seyedmehdi Mavalizadeh ◽  
Moones Rahmandoust ◽  
Andreas Öchsner
Keyword(s):  
Carbon Nanotube ◽  
Young’S Modulus ◽  
Case Studies ◽  
Elastic Properties ◽  
Representative Volume Element ◽  
Volume Fraction ◽  
Young's Modulus ◽  
Volume Element ◽  
Matrix Volume ◽  
The Matrix

In this study, a finite element model of a representative volume element that contains a hollow and filled single-walled Carbon nanotube (SWCNT) in two case studies was generated. It was assumed that the nanocomposites have geometric periodicity with respect to local length scale and the elastic properties can be represented by those of the representative volume element (RVE). Elastic properties in agreement with existing literature values for the Carbon nanotube and the matrix were assigned. Then for the two case studies, the tensile test was simulated to find the effect of the geometry, i.e. the volume fraction of matrix and SWCNT's properties variation, on the effective Young's modulus of the structure. In another approach, by applying perpendicular loading to the tube direction, the effect of matrix volume fraction on the transverse Young's modulus was studied. The investigations showed that for both RVEs with filled SWCNT and hollow SWCNT, the effective Young's modulus of the structure decreases approximately linear as the matrix volume fraction increases. The value of Young's modulus of the RVE with a filled Carbon nanotube was obtained to be higher than the RVE with the hollow Carbon nanotube. In addition, by increasing the tube diameter, the effective Young's modulus of the structure increases and the transverse Young's modulus decreases approximately linear for filled tubes but this parameter remains rather constant in the case of the hollow tube by increasing the matrix volume fraction.

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