Effects of hydrogen peroxide solution on the biomechanics of porcine cornea

2021 ◽  
pp. 112067212199664
Author(s):  
Zuoxiang Pang ◽  
Lijun Wang ◽  
Chunxiao Zhang ◽  
Jia Wang ◽  
Zhipeng Gao ◽  
...  

Objectives: To determine the biomechanical changes of porcine corneas after the application of hydrogen peroxide(H2O2) solution. Methods: Fifty-five porcine eyeballs with similar sizes were divided into 11 groups based on the H2O2 application. The eyeballs were treated with the following concentrations of H2O2 solution: 1 mol/L, 500 mmol/L, 250 mmol/L, 125 mmol/L, 62.5 mmol/L, 31.25 mmol/L, 15.63 mmol/L, 7.81 mmol/L, 3.91 mmol/L, 0.9% saline, or blank. The eyeballs were immersed into the solution for 30 min. The biomechanics of each cornea in the different groups was determined soon after the indentation and tensile tests. We calculated the average Young’s modulus of the different groups to determine the effects of H2O2 solution on porcine corneas. The comparison between the groups was conducted using ANOVA analysis. Moreover, the safety of each concentration of H2O2 solution on the corneal tissues was determined by histopathological examination. Results: The Young’s modulus was significantly different among all the groups ( p = 0.003). The modulus was the highest in the group treated with 3.91 mmol/L H2O2 and it was significantly different from that in the group treated with 0.9% saline or the blank group, for both the indentation and tensile tests. Histopathological examination showed that H2O2 at a concentration of ⩾62.5 mmol/L damaged the epithelium, stroma, or both, while H2O2 at a concentration ⩽31.25 mmol/L did not change the morphology of the epithelium or stroma. Conclusions: Treatment with 3.91 mmol/L H2O2 solution can safely and effectively increase the biomechanical strength of the cornea.

2011 ◽  
Vol 146 ◽  
pp. 12-26 ◽  
Author(s):  
A. Gherissi ◽  
R.Ben Cheikh ◽  
E. Dévaux ◽  
Fethi Abbassi

In this study, we present the manufacturing process of two new composites materials in the form of long fibers of polylactic-acid (PLA) or polypropylene (PP), reinforced by cellulose whiskers micro-fibers loads. In order to evaluate the mechanical properties of these advanced materials, a several uniaxial tensile tests were carried out. The PP and the PLA have initially been spinning without the addition of cellulose whiskers micro-fibers. In order to study the effects of cellulose whiskers micro-fibers reinforcements in the Mechanical behavior of the PLA and PP filaments, we determinate the proprieties of these advanced material from the tensile results. For the PP composite filaments material case, the whiskers reinforcement increases Young's modulus and failure resistance, but it reduces the limit strength failure. For the PLA composites the addition of 1% wt of cellulose whiskers from the total volume fraction of the material, increase the Young’s modulus more than 50% and a decrease of the failure resistance and the limit strength of composite. The obtained composites fibers are very rigid and brittle. What follows, that the addition of cellulose whiskers micro fibers in PP matrix, provides mechanical properties more convenient compared to the PLA matrix.


2001 ◽  
Vol 702 ◽  
Author(s):  
Shigeyasu Amada

ABSTRACTBamboo is a typical composite material which is axially reinforced by very strong fibers. So that, the fibers play an important role for the bamboo structure. The elastic properties of the bamboo culm have been measured only by tensile test so far, which needs a large specimen. Recently ultra-sonic technique, which has a simple procedure and uses a small specimen, has been applied to woods as well as metals. This report reviews about the elastic properties of bamboo and Hemp palm fibers. The Young's modulus and Poisson's ratio of the bamboo fibers are measured by ultra-sonic method with a transmitting wave. On the other hand, the strength of the bamboo and Hemp palm fibers are measured by the tensile tests. Using the volume fraction of fibers in the specimen and mixture principle, the Young's modulus and strength of the fibers and parenchyma were obtained. The fiber has a high strength up to 1GPa and an strong anisotropic property because its axial Young's modulus has 7 times higher than the one in the transverse direction.


Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1491 ◽  
Author(s):  
Vasile Danut Cojocaru ◽  
Anna Nocivin ◽  
Corneliu Trisca-Rusu ◽  
Alexandru Dan ◽  
Raluca Irimescu ◽  
...  

The influence of complex thermo-mechanical processing (TMP) on the mechanical properties of a Ti-Nb-Zr-Fe-O bio-alloy was investigated in this study. The proposed TMP program involves a schema featuring a series of severe plastic deformation (SPD) and solution treatment (STs). The purpose of this study was to find the proper parameter combination for the applied TMP and thus enhance the mechanical strength and diminish the Young’s modulus. The proposed chemical composition of the studied β-type Ti-alloy was conceived from already-appreciated Ti-Nb-Ta-Zr alloys with high β-stability by replacing the expensive Ta with more accessible Fe and O. These chemical additions are expected to better enhance β-stability and thus avoid the generation of ω, α’, and α” during complex TMP, as well as allow for the processing of a single bcc β-phase with significant grain diminution, increased mechanical strength, and a low elasticity value/Young’s modulus. The proposed TMP program considers two research directions of TMP experiments. For comparisons using structural and mechanical perspectives, the two categories of the experimental samples were analyzed using SEM microscopy and a series of tensile tests. The comparison also included some already published results for similar alloys. The analysis revealed the advantages and disadvantages for all compared categories, with the conclusions highlighting that the studied alloys are suitable for expanding the database of possible β-Ti bio-alloys that could be used depending on the specific requirements of different biomedical implant applications.


2005 ◽  
Vol 475-479 ◽  
pp. 4097-4102 ◽  
Author(s):  
I. Kaplan-Ashiri ◽  
S.R. Cohen ◽  
K. Gartsman ◽  
R. Rosentsveig ◽  
V. Ivanovskaya ◽  
...  

The Young’s modulus of WS2 nanotubes is an important property for various applications. Measurements of the mechanical properties of individual nanotubes are challenging because of the small size of the tubes. Lately, measurements of the Young’s modulus by buckling of an individual nanotube using an atomic force microscope1 resulted in an average value of 171GPa. Tensile tests of individual WS2 nanotubes were performed experimentally using a scanning electron microscope and simulated tensile tests of MoS2 nanotubes were performed by means of a densityfunctional tight-binding (DFTB) based molecular dynamics (MD) scheme. Preliminary results for WS2 nanotubes show Young’s modulus value of ca.162GPa, tensile strength value of ca. 13GPa and average elongation of ca. 12%. MD simulations resulted in elongation of 19% for zigzag and 17% for armchair MoS2 single wall nanotubes. Since MoS2 and WS2 nanotubes have similar structures the same behavior is expected for both, hence there is a good agreement regarding the elongation of WS2 nanotubes between experiment and simulation.


Author(s):  
Joselyn Cardenas ◽  
Calvin M. Stewart

In the advancement of Additive Manufacturing (AM) technologies, 3D desktop printers have become an accessible solution to address the current manufacturing practices for most industries and the general public. This study explores the effect default build parameters have on the tensile properties of additive manufactured parts by comparing the Young’s Modulus and tensile strength of polylactic acid (PLA) in the elastic region before and after the AM process through experiments and numerical simulations. The build parameters are specified via MakerBot Desktop — the file preparation software for the MakerBot Replicator 3D printer used to create the specimens tested herein. This work presents the tensile mechanical properties for specimens built using low infill rate, low layer resolution, and standard build speed and extrusion temperature to recreate the worst possible part quality attainable using MakerBot 3D Desktop printers. Using these build parameters results in a part with a hollow honeycomb interior structure, and due to its heterogeneous cross sectional area, experimental stress-strain curves do not accurately represent its physical response to tensile loading. Therefore in this case, an experimental-numerical study of the 3D printed specimens is performed, using the load-displacement experimental data acquired from tensile tests to calibrate the ANSYS Structural Mechanics simulations. The goal is to optimize the material properties in our simulation such that the equivalent strain magnitude matches the experiments. This is an approach to determine the experimental Young’s modulus of PLA additive manufactured parts where the AM process, heterogeneous structure, and size greatly influence the part strength. This is completed by studying the worst part quality possible first to better understand this effect. Tensile tests are performed using an ADMET 5603 Universal Test Machine (UTM) synched with a Correlated Solutions 3D Digital Image Correlation (DIC) system. A fine heterogeneous speckle pattern is sprayed on the specimens and used by the DIC system to obtain surface contours of deformation. This data is compared to the displacement fields in the finite element analysis (FEA) simulation of the specimen. When compared to the pre-manufacturing PLA, additive manufactured parts exposed that the post-processed stiffness of the material is increased when tested under this loading condition. The Poisson’s ratio for printed PLA was also noted to decrease when compared to pre-manufactured PLA, due to the larger longitudinal deformation compared to the transverse. Specimens failed by brittle fracture across the hex pattern, showing limited deformation and failing short after. The failure location based on the influence interior geometry has on failure showed that specimens failed by brittle fracture across the hex pattern, initiating fracture in the same region of all specimens.


2009 ◽  
Vol 2009 ◽  
pp. 1-6 ◽  
Author(s):  
Qinhua Jin ◽  
Tie Li ◽  
Ping Zhou ◽  
Yuelin Wang

Nanostructures of SingleCrystalSilicon (SCS) with superior electrical, mechanical, thermal, and optical properties are emerging in the development of novel nanodevices. Mechanical properties especially Young's modulus are essential in developing and utilizing such nanodevices. In this paper, experimental researches including bending tests, resonance tests, and tensile tests on Young' s modulus of nanoscaled SCS are reviewed, and their results are compared. It was found that the values ofEmeasured by different testing methods cannot match to each other. As the differences cannot be explained as experimental errors, it should be understood by taking surface effect into account. With a simplified model, we qualitatively explained the difference inEvalue measured by tensile test and by resonance test for Si nanobeams.


2014 ◽  
Vol 28 (07) ◽  
pp. 1450051 ◽  
Author(s):  
Y. Y. WANG ◽  
M. TIAN ◽  
H. X. XU ◽  
P. FAN

This paper aims to investigate the impact of moisture on mechanical properties of insulation paper. According to the molecular modeling approach proposed by Theodorou, the amorphous cellulose models of insulation paper with different moisture contents were built up to calculate mechanical parameters and hydrogen bond networks. And relevant conclusions could be drawn through further analysis on these calculation results: water molecules can destroy hydrogen bond network between the neighboring cellulose molecules, which might be responsible for the significant decrease of Young's modulus and other mechanical parameters, while no appreciable effect of intramolecular hydrogen bonds on mechanical properties was detected. Thus tensile tests were also carried out to study the moisture influence on the Young's modulus, by which the result of the simulation was approved.


Hitherto, investigations into the elastic properties of metals have been confined to comparatively low temperatures. Gray, Dunlop, and Blyth have measured the modulus of rigidity and Young’s modulus for wires up to temperatures of 100° C., and found that both these quantities decrease as the temperature rises. Martens determined the influence of heat on the strength of iron up to temperatures of 600° C., but his experiments were the ordinary tensile tests carried to rupture, and though he also found a substantial diminution of Young’s modulus with rise of temperature, he did not go into the point fully, being mainly concerned with breaking stress and elongation. In the experiments here described the elastic properties of steel and iron have been investigated at higher temperatures, ranging up to 800° C., and for stresses greatly below that required to rupture the material. We have found that as the temperature rises the stress-strain relations undergo a remarkable change, which may best be expressed by saying that what is variously called the “time-effect,” or “elastische nachwirkung,” or “creeping,” increases greatly with the temperature. Steel, at high temperatures, behaves like indiarubber or glass; if it is stressed for a time, and the stress removed, it does not at once recover, but after the immediate elastic recovery there is a slow contraction perceptible for many minutes. Such “creeping” can be detected at ordinary temperatures, but at a red heat it attains a different order of magnitude, becoming (in its total amount) a substantial fraction of the whole deformation.


Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1175
Author(s):  
Pavel A. Somov ◽  
Eugene S. Statnik ◽  
Yuliya V. Malakhova ◽  
Kirill V. Nyaza ◽  
Alexey I. Salimon ◽  
...  

Recent years witnessed progressive broadening of the practical use of 3D-printed aluminium alloy parts, in particular for specific aerospace applications where weight saving is of great importance. Selective laser melting (SLM) is an intrinsically multi-parametric fabrication technology that offers multiple means of controlling mechanical properties (elastic moduli, yield strength, and ductility) through the control over grains size, shape, and orientation. Targeted control over mechanical properties is achieved through the tuning of 3D-printing parameters and may even obviate the need of heat treatment or mechanical post-processing. Systematic studies of grain structure for different printing orientations with the help of EBSD techniques in combination with mechanical testing at different dimensional levels are the necessary first steps to implement this agenda. Samples of 3D-printable Al-Mg-Si RS-333 alloy were fabricated in three orientations with respect to the principal build direction and the fast laser beam scanning direction. Sample structure and proper-ties were investigated using a number of techniques, including EBSD, in situ SEM tensile testing, roughness measurements, and nanoindentation. The as-printed samples were found to display strong variation in Young’s modulus values from nanoindentation (from 43 to 66 GPa) and tensile tests (from 54 to 75 GPa), yield stress and ultimate tensile strength (100–195 and 130–220 MPa) in different printing orientations, and almost constant hardness of about 0.8 GPa. A further preliminary study was conducted to assess the effect of surface finishing on the mechanical performance. Surface polishing was seen to reduce Young’s modulus and yield strength but improves ductility, whereas the influence of sandblasting was found to be more controversial. The experimental results are discussed in connection with the grain morphology and orientation.


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