scholarly journals Active Manipulation of ECM Stiffness

Author(s):  
Peter C. Y. Chen ◽  
Sahan C. B. Herath ◽  
Dong-an Wang ◽  
Kai Su ◽  
Kin Liao ◽  
...  

The mechanical properties of the microstructures surrounding cells influence the behavior of cells in differentiation, proliferation, and apoptosis, etc. The stiffness of the extra-cellular microenvironment has been shown to be one such mechanical property [1][2]. Studies reported in the literature concerning the stiffness of the extracellular microenvironment mainly sought to understand the scientific principles and mechanisms underlying its effect on cell-environment interaction [3]. This paper describes an approach that achieves such manipulation, and reports experimental results that demonstrate the effectiveness of this proposed approach.

2010 ◽  
Vol 146-147 ◽  
pp. 310-313
Author(s):  
Ying Peng ◽  
Jian Hua Liu

The synergistic toughening of UPR composite by rigid particles of organic PA6 and inorganic nano-SiO2 was studied. The effects of PA6 and SiO2 on the notched impact and tensile strength of the UPR composite were studied by means of the mechanical properties test. The experimental results indicated that the notched impact strength was improved and its effect was evident when 7-9%rigid particles were applied and the tensile strength was improved when the 2-5% rigid particles were applied. The composite of PA6/SiO2 ( 2/1) exhibited good mechanical property in the synergistic toughening. By the micromechanical analysis of composite, we thought that the stiffness of composite materials was determined by the stress suffered the rigid particles and the deformation of UPR polymer phase.


2020 ◽  
Vol 13 ◽  
Author(s):  
V. Arumugaprabu ◽  
K.Arun Prasath ◽  
S. Mangaleswaran ◽  
M. Manikanda Raja ◽  
R. Jegan

: The objective of this research is to evaluate the tensile, impact and flexural properties of flax fiber and basalt powder filled polyester composite. Flax fiber is one of the predominant reinforcement natural fiber which possess good mechanical properties and addition of basalt powder as a filler provides additional support to the composite. The Composites are prepared using flax fiber arranged in 10 layers with varying weight percentage of the basalt powder as 5 wt.%, 10 wt.%, 15 wt.%, 20 wt.%, 25 wt.% and 30 wt.% respectively. From the results it is inferred that the composite combination 10 Layers of flax / 5 wt.%, basalt Powder absorbs more tensile load of 145 MPa. Also, for the same combination maximum flexural strength is about 60 MPa. Interestingly in the case of impact strength more energy was absorbed by 10 layers of flax and 30 wt.% of basalt powder. In addition, the failure mechanism of the composites also discussed briefly using SEM studies.


Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 799
Author(s):  
Dingkun Xie ◽  
Lixiong Cai ◽  
Jie Wang

Adverse side-effects occurred in slurry foaming and thickening process when carbide slag was substituted for quicklime in HCS-AAC. Cement accelerators were introduced to modify the slurry foaming and coagulating process during pre-curing. Meanwhile, the affiliated effects on the physical-mechanical properties and hydration products were discussed to evaluate the applicability and influence of the cement accelerator. The hydration products were characterized by mineralogical (XRD) and thermal analysis (DSC-TG). The results indicated that substituting carbide slag for quicklime retarded slurry foaming and curing progress; meanwhile, the induced mechanical property declination had a negative effect on the generation of C–S–H (I) and tobermorite. Na2SO4 and Na2O·2.0SiO2 can effectively accelerate the slurry foaming rate, but the promoting effect on slurry thickening was inconspicuous. The compressive strength of HCS-AAC obviously declined with increasing cement coagulant content, which was mainly ascribed to the decrease in bulk density caused by the accelerating effect on the slurry foaming process. Dosing Na2SO4 under 0.4% has little effect on the generation of strength contributing to hydration products while the addition of Na2O·2.0SiO2 can accelerate the generation and crystallization of C–S–H, which contributed to the high activity gelatinous SiO2 generated from the reaction between Na2O·2.0SiO2 and Ca(OH)2.


2013 ◽  
Vol 770 ◽  
pp. 308-311 ◽  
Author(s):  
Ming Dong Yi ◽  
Chong Hai Xu ◽  
Zhao Qiang Chen ◽  
Guang Yong Wu

A new nanomicro composite self-lubricating ceramic tool material was prepared with vacuum hot pressing technique. The effect of nanoAl2O3 powders on the microstructure and mechanical properties of nanomicro composite self-lubricating ceramic tool material was investigated. With the increase of nanoAl2O3 content, the hardness and fracture toughness first up then down. When the nanoAl2O3 content is 4 vol.%, the flexural strength, hardness and fracture toughness reaches 562 MPa, 8.46 MPa·m1/2 and 18.95 GPa, respectively. The microstructure and mechanical property of nanomicro composite self-lubricating ceramic tool material can be improved by the grain refinement strengthening of nanoAl2O3.


2013 ◽  
Vol 405-408 ◽  
pp. 1616-1622
Author(s):  
Guo Hui Cao ◽  
Jia Xing Hu ◽  
Kai Zhang ◽  
Min He

In order to research on mechanical properties of flexible suspension bridges, a geometric nonlinear analysis method was used to simulate on the experimental results, and carried on static loading test finally. In the loading test process, the deformations were measured in critical section of the suspension bridge, and displacement values of measured are compared with simulation values of the finite element simulation. Meanwhile the deformations of the main cable sag are observed under classification loading, the results show that the main cable sag increment is basically linear relationship with the increment of mid-span loading and tension from 3L/8 and 5L/8 to L/2 section, the main cable that increasing unit sag required mid-span loads and tension are gradually reduce in near L/4 and 3L/4 sections and gradually increase in near L/8 and 7L/8 sections and almost equal in near L/2, 3L/8 and 5L/8 sections. From the experimental results, the flexible suspension bridge possess good mechanical properties.


1998 ◽  
Vol 520 ◽  
Author(s):  
Y. H. Zhang ◽  
K. C. Gong

ABSTRACTHybrids of quaternary ammonium-modified montmorillonites and polypropylene were prepared by melting intercalation. Results of mechanical property measurements show that, tensile strength, modulus and impact strength of PP composites are greatly enhanced simultaneously by a small addition amount of modified montmorillonites.


2017 ◽  
Vol 10 (2) ◽  
pp. 477-508 ◽  
Author(s):  
C. F.R. SANTOS ◽  
R. C. S. S. ALVARENGA ◽  
J. C. L. RIBEIRO ◽  
L. O CASTRO ◽  
R. M. SILVA ◽  
...  

Abstract This work developed experimental tests and numerical models able to represent the mechanical behavior of prisms made of ordinary and high strength concrete blocks. Experimental tests of prisms were performed and a detailed micro-modeling strategy was adopted for numerical analysis. In this modeling technique, each material (block and mortar) was represented by its own mechanical properties. The validation of numerical models was based on experimental results. It was found that the obtained numerical values of compressive strength and modulus of elasticity differ by 5% from the experimentally observed values. Moreover, mechanisms responsible for the rupture of the prisms were evaluated and compared to the behaviors observed in the tests and those described in the literature. Through experimental results it is possible to conclude that the numerical models have been able to represent both the mechanical properties and the mechanisms responsible for failure.


2006 ◽  
Vol 321-323 ◽  
pp. 1070-1073
Author(s):  
Ye Yeon Won ◽  
Myong Hyun Baek ◽  
Wen Quan Cui ◽  
Kwang Kyun Kim

This study investigates micro-structural and mechanical properties of trabecular bone in human femoral head with and without osteoporosis using a micro-CT and a finite element model. 15 cored trabecular bone specimens with 20 of diameter were obtained from femoral heads with osteoporosis resected for total hip arthroplasty, and 5 specimens were removed from femoral head of cadavers, which has no history of musculoskeletal diseases. A high-resolution micro-CT system was used to scan each specimen to obtain histomorphometry indexes. Based on the micro-images, a FE-model was created to determine mechanical property indexes. While the non-osteoporosis group had increases the trabecular thickness, the bone volume, the bone volume fraction, the degree of anisotropy and the trabecular number compared with those of osteoporotic group, the non-osteoporotic group showed decreases in trabecular separation and structure model index. Regarding the mechanical property indexes, the reaction force and the Young's modulus were lower in the osteoporotic group than in non-osteoporotic group. Our data shows salient deteriorations in trabecular micro-structural and mechanical properties in human femoral head with osteoporosis.


2016 ◽  
Vol 850 ◽  
pp. 671-678
Author(s):  
Jian Wei Niu ◽  
Lie Jun Li ◽  
Hai Jun Liu ◽  
Ji Xiang Gao ◽  
Chuan Dong Ren

The inoculation and fading behavior of Sr-modified aluminum alloy A356. 2 were studied for air bag bracket produced by squeeze casting. The effects of Sr, P, B contents and casting temperature on the microstructure and eutectic silicon morphology in different periods of inoculation were investigated by SEM and direct-reading Spectrometer. The influence of inoculation fading rate and addition of Sr on the casting mechanical properties and hydrogen absorption was studied. The experimental results showed that the inoculation process was completed in 1 h, and the eutectic silicon morphology can be maintained in almost subsequent 40 h after the addition of Sr. The fading rate decreased appreciably with the increase of casing temperature, P and B contents. The deleterious effect of the inoculation fading of Sr on the casting mechanical property can be compensated by the squeeze casting.


Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 423
Author(s):  
Thorsten Michler ◽  
Frank Schweizer ◽  
Ken Wackermann

It is well-documented experimentally that the influence of hydrogen on the mechanical properties of structural alloys like austenitic stainless steels, nickel superalloys, and carbon steels strongly depends on temperature. A typical curve plotting any hydrogen-affected mechanical property as a function of temperature gives a temperature THE,max, where the degradation of this mechanical property reaches a maximum. Above and below this temperature, the degradation is less. Unfortunately, the underlying physico-mechanical mechanisms are not currently understood to the level of detail required to explain such temperature effects. Though this temperature effect is important to understand in the context of engineering applications, studies to explain or even predict the effect of temperature upon the mechanical properties of structural alloys could not be identified. The available experimental data are scattered significantly, and clear trends as a function of chemistry or microstructure are difficult to see. Reported values for THE,max are in the range of about 200–340 K, which covers the typical temperature range for the design of structural components of about 230–310 K (from −40 to +40 °C). That is, the value of THE,max itself, as well as the slope of the gradient, might affect the materials selection for a dedicated application. Given the current lack of scientific understanding, a statistical approach appears to be a suitable way to account for the temperature effect in engineering applications. This study reviews the effect of temperature upon hydrogen effects in structural alloys and proposes recommendations for test temperatures for gaseous hydrogen applications.


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