Separation of a diastereomeric diol pair using the mechanical properties of crystals

CrystEngComm ◽

10.1039/d1ce01055g ◽

2021 ◽

Author(s):

Rama Krishna Gamidi ◽

Monica Dandawate ◽

Srinu Tothadi ◽

Rahul Choudhury ◽

Ashwini K. Nangia ◽

...

Keyword(s):

Mechanical Properties ◽

Mechanical Response ◽

Diastereomeric Pair

The visually indistinguishable acicular crystals of a (2S,3R/S)-3-ethyl-1-phenylhex-5-ene-2,3-diol (ephd) diastereomeric pair are separated via the mechanical response based on elastic (2S,3R, right) and brittle (2S,3S, left) crystals.

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The Effect of Different Annealing Strategies on the Microstructure Development and Mechanical Response of Austempered Steels

Metals ◽

10.3390/met11071041 ◽

2021 ◽

Vol 11 (7) ◽

pp. 1041

Author(s):

Eliseo Hernandez-Duran ◽

Luca Corallo ◽

Tanya Ros-Yanez ◽

Felipe Castro-Cerda ◽

Roumen H. Petrov

Keyword(s):

Mechanical Properties ◽

Retained Austenite ◽

Mechanical Response ◽

Steel Grade ◽

The Other ◽

Microstructure Development ◽

Microstructural Refinement ◽

Heterogeneous Distribution ◽

Parent Austenite ◽

Conventional Annealing

This study focuses on the effect of non-conventional annealing strategies on the microstructure and related mechanical properties of austempered steels. Multistep thermo-cycling (TC) and ultrafast heating (UFH) annealing were carried out and compared with the outcome obtained from a conventionally annealed (CA) 0.3C-2Mn-1.5Si steel. After the annealing path, steel samples were fast cooled and isothermally treated at 400 °C employing the same parameters. It was found that TC and UFH strategies produce an equivalent level of microstructural refinement. Nevertheless, the obtained microstructure via TC has not led to an improvement in the mechanical properties in comparison with the CA steel. On the other hand, the steel grade produced via a combination of ultrafast heating annealing and austempering exhibits enhanced ductility without decreasing the strength level with respect to TC and CA, giving the best strength–ductility balance among the studied steels. The outstanding mechanical response exhibited by the UFH steel is related to the formation of heterogeneous distribution of ferrite, bainite and retained austenite in proportions 0.09–0.78–0.14. The microstructural formation after UFH is discussed in terms of chemical heterogeneities in the parent austenite.

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Evolution of Meniscal Biomechanical Properties with Growth: An Experimental and Numerical Study

Bioengineering ◽

10.3390/bioengineering8050070 ◽

2021 ◽

Vol 8 (5) ◽

pp. 70

Author(s):

Marco Ferroni ◽

Beatrice Belgio ◽

Giuseppe M. Peretti ◽

Alessia Di Giancamillo ◽

Federica Boschetti

Keyword(s):

Mechanical Properties ◽

Stress Relaxation ◽

Developmental Stage ◽

Mechanical Response ◽

Numerical Study ◽

Numerical Models ◽

Mechanical Stimulus ◽

Specific Response ◽

Mechanical Parameters ◽

Biochemical Analyses

The menisci of the knee are complex fibro-cartilaginous tissues that play important roles in load bearing, shock absorption, joint lubrication, and stabilization. The objective of this study was to evaluate the interaction between the different meniscal tissue components (i.e., the solid matrix constituents and the fluid phase) and the mechanical response according to the developmental stage of the tissue. Menisci derived from partially and fully developed pigs were analyzed. We carried out biochemical analyses to quantify glycosaminoglycan (GAG) and DNA content according to the developmental stage. These values were related to tissue mechanical properties that were measured in vitro by performing compression and tension tests on meniscal specimens. Both compression and tension protocols consisted of multi-ramp stress–relaxation tests comprised of increasing strains followed by stress–relaxation to equilibrium. To better understand the mechanical response to different directions of mechanical stimulus and to relate it to the tissue structural composition and development, we performed numerical simulations that implemented different constitutive models (poro-elasticity, viscoelasticity, transversal isotropy, or combinations of the above) using the commercial software COMSOL Multiphysics. The numerical models also allowed us to determine several mechanical parameters that cannot be directly measured by experimental tests. The results of our investigation showed that the meniscus is a non-linear, anisotropic, non-homogeneous material: mechanical parameters increase with strain, depend on the direction of load, and vary among regions (anterior, central, and posterior). Preliminary numerical results showed the predominant role of the different tissue components depending on the mechanical stimulus. The outcomes of biochemical analyses related to mechanical properties confirmed the findings of the numerical models, suggesting a specific response of meniscal cells to the regional mechanical stimuli in the knee joint. During maturation, the increase in compressive moduli could be explained by cell differentiation from fibroblasts to metabolically active chondrocytes, as indicated by the found increase in GAG/DNA ratio. The changes of tensile mechanical response during development could be related to collagen II accumulation during growth. This study provides new information on the changes of tissue structural components during maturation and the relationship between tissue composition and mechanical response.

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Role of Interfacial Interactions on Mechanical Properties of Biomimetic Composites for Bone Tissue Engineering

MRS Proceedings ◽

10.1557/proc-0898-l08-03 ◽

2005 ◽

Vol 898 ◽

Cited By ~ 1

Author(s):

Devendra Verma ◽

Rahul Bhowmik ◽

Bedabibhas Mohanty ◽

Dinesh R Katti ◽

Kalpana S Katti

Keyword(s):

Mechanical Properties ◽

Tissue Engineering ◽

Bone Tissue Engineering ◽

Bone Tissue ◽

Mechanical Response ◽

Density Ratio ◽

Interfacial Interactions ◽

Porous Composites ◽

Properties Of Composites

AbstractInterfaces play an important role in controlling the mechanical properties of composites. Optimum mechanical strength of scaffolds is of prime importance for bone tissue engineering. In the present work, molecular dynamics simulations and experimental studies have been conducted to study effect of interfacial interactions on mechanical properties of composites for bone replacement. In order to mimic biological processes, hydroxyapatite (HAP) is mineralized in presence of polyacrylic acid (PAAc) (in situ HAP). Further, solid and porous composites of in situ HAP with polycaprolactone (PCL) are made. Mechanical tests of composites of in situ HAP with PAAc have shown improved strain recovery, higher modulus/density ratio and also improved mechanical response in simulated body fluid (SBF). Simulation studies indicate potential for calcium bridging between –COO− of PAAc and surface calcium of HAP. This fact is also supported by infrared spectroscopic studies. PAAc modified surfaces of in situ HAP offer means to control the microstructure and mechanical response of porous composites. Nanoindentation experiments indicate that apatite grown on in situ HAP/PCL composites from SBF has improved elastic modulus and hardness. This work gives insight into the interfacial mechanisms responsible for mechanical response as well as bioactivity in biomaterials.

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Mechanical Response of Al-1.09Mg2Si Alloy under Varying Mould and Thermal Ageing Conditions

Journal of Metallurgy ◽

10.1155/2012/921235 ◽

2012 ◽

Vol 2012 ◽

pp. 1-7

Author(s):

O. I. Sekunowo ◽

G. I. Lawal ◽

S. O. Adeosun

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Ultimate Tensile Strength ◽

Ambient Temperature ◽

Mechanical Response ◽

Ageing Time ◽

Thermal Ageing ◽

Alloy Ingot ◽

Solution Treated ◽

Crucible Furnace

Samples of the 6063 (Al-1.09Mg2Si) alloy ingot were melted in a crucible furnace and cast in metal and sand moulds, respectively. Standard tensile, hardness, and microstructural test specimens were prepared from cast samples, solution treated at 520∘C, soaked for 6 hrs, and immediately quenched at ambient temperature in a trough containing water to assume a supersaturated structure. The quenched specimens were then thermally aged at 175∘C for 3–7 hrs. Results show that at different ageing time, varied fractions of precipitates and intermetallics evolved in the specimens’ matrices which affect the resulting mechanical properties. The metal mould specimens aged for four hours (MTA-4) exhibited superior ultimate tensile strength of 247.8 MPa; microhardness, 68.5 HV; elongation, 28.2% . It is concluded that the extent of improvement in mechanical properties depends on the fractions, coherence, and distribution of precipitates along with the type of intermetallics developed in the alloy during ageing process.

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Enhancing Mechanical Response of Monolithic Magnesium Using Nano-NiTi (Nitinol) Particles

Metals ◽

10.3390/met8121014 ◽

2018 ◽

Vol 8 (12) ◽

pp. 1014 ◽

Cited By ~ 20

Author(s):

Gururaj Parande ◽

Vyasaraj Manakari ◽

Saif Wakeel ◽

Milli Kujur ◽

Manoj Gupta

Keyword(s):

Mechanical Properties ◽

Mechanical Response ◽

Hot Extrusion ◽

Nickel Titanium ◽

Structure Property ◽

Microstructural Characteristics ◽

Magnesium Matrix ◽

Melt Deposition ◽

Synthesized Materials ◽

Minimal Adverse Effect

The present study focuses on investigating the effects of Nickel-Titanium (NiTi) nanoparticles on the microstructure and properties of pure Mg. Mg composites containing varying weight percentages (0.5, 1, 1.5, 3) of NiTi nanoparticles were fabricated using Disintegrated Melt Deposition (DMD), followed by hot extrusion. The synthesized materials were characterized in order to investigate their physical, microstructural and mechanical properties. Synthesized materials were characterized for their density and porosity levels, microstructural characteristics, and mechanical response. Superior grain refinement was realized by the presence of NiTi nanoparticles in the magnesium matrix. The addition of NiTi nanoparticles resulted in strength property enhancements of pure Mg with minimal adverse effect on the ductility. Structure-property evaluations are detailed in the current study.

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Determination of Cellular Mechanical Properties by Cell Poking, With an Application to Leukocytes

Journal of Biomechanical Engineering ◽

10.1115/1.2891186 ◽

1990 ◽

Vol 112 (3) ◽

pp. 283-294 ◽

Cited By ~ 104

Author(s):

G. I. Zahalak ◽

W. B. McConnaughey ◽

E. L. Elson

Keyword(s):

Mechanical Properties ◽

Final Section ◽

Mechanical Response ◽

Living Cells ◽

Micropipette Aspiration ◽

Current Status ◽

Technical Description ◽

Analytical Results ◽

Simple Models

In this paper we review the cell-poking technique as an approach for investigating the mechanical properties of living cells. We first summarize the rationale for the technique and the mainly qualitative results obtained so far. Then we provide a technical description of the instrument as it is configured at present. This is followed by a discussion of the current status of analytical results available for interpreting cell-poking measurements. In the final section we apply these results to an analysis of unmodulated and modulated lymphocytes and neutrophils, and conclude that the mechanical response of these leukocytes to indentation is not consistent with simple models developed by previous investigators on the basis of micropipette-aspiration experiments.

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Preliminary study on the mechanical behavior of friction spot welds

Soldagem & Inspeção ◽

10.1590/s0104-92242009000300007 ◽

2009 ◽

Vol 14 (3) ◽

pp. 238-247 ◽

Cited By ~ 27

Author(s):

José Antônio Esmerio Mazzaferro ◽

Tonilson de Souza Rosendo ◽

Cíntia Cristiane Petry Mazzaferro ◽

Fabiano Dornelles Ramos ◽

Marco Antônio Durlo Tier ◽

...

Keyword(s):

Mechanical Properties ◽

Mechanical Behavior ◽

Spot Welding ◽

Mechanical Response ◽

Analysis Procedure ◽

Research Centre ◽

Friction Stir ◽

Lap Shear ◽

State Process ◽

Welding Processes

The Friction Spot Welding - FSpW is a solid-state process that allows joining two or more metal sheets in lap configuration with no residual keyhole as occurs in the Friction Stir Welding - FSW process. The present work reports part of the efforts made at GKSS Research Centre to better understand the complex phenomena that take place during FSpW of aluminum alloys and establish the mechanical response of the resulting joints. Over the recent years the research on modeling friction based welding processes has increased considerably. Most of the works related to this subject deal with the process mechanics. On the other hand, some investigations have shown how the process variables affect the mechanical properties of the joints, but it is very difficult to find quantitative results that can be readily used for mechanical design purposes. The aim of this work is to develop an analysis procedure based on the process characteristics that allows evaluating how the resulting geometry and microstructure affect the joint mechanical behavior. For this, the results of the mechanical tests obtained on AA2024-T3 aluminum alloy were used to calibrate and validate a numerical model that was used to predict the joint failure mode. The model reproduced the specimen geometry and load conditions adopted in the lap-shear and cross-tensile tests. The joint was considered as formed by three main regions (SZ - stir zone, TMAZ - thermo mechanically affected zone and HAZ - heat affected zone) whose properties and dimensions were based in microhardness evaluation and macrographic analysis of welded specimens. It was observed a good agreement between the simulation results and experimental data. The numerical modeling of the joints allows the prediction of the joint mechanical properties, as well as to understand how a change in geometry and property of each region affects the final mechanical behavior. Based in the obtained results, the analysis procedure can be easily extended to the related friction based spot processes as Friction Stir Spot Welding - FSSW.

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Effects of dynamic indentation on the mechanical response of materials

Journal of Materials Research ◽

10.1557/jmr.2008.0205 ◽

2008 ◽

Vol 23 (6) ◽

pp. 1604-1613 ◽

Cited By ~ 21

Author(s):

M.J. Cordill ◽

N.R. Moody ◽

W.W. Gerberich

Keyword(s):

Thin Films ◽

Mechanical Properties ◽

Mechanical Response ◽

Length Scale ◽

Polycrystalline Nickel ◽

Dynamic Indentation ◽

Crystalline Materials ◽

Fused Quartz ◽

Hardness Values ◽

Measured Hardness

Dynamic indentation techniques are often used to determine mechanical properties as a function of depth by continuously measuring the stiffness of a material. The dynamics are used by superimposing an oscillation on top of the monotonic loading. Of interest was how the oscillation affects the measured mechanical properties when compared to a quasi-static indent run at the same loading conditions as a dynamic. Single crystals of nickel and NaCl as well as a polycrystalline nickel sample and amorphous fused quartz and polycarbonate have all been studied. With respect to dynamic oscillations, the result is a decrease of the load at the same displacement and thus lower measured hardness values of the ductile crystalline materials. It has also been found that the first 100 nm of displacement are the most affected by the oscillating tip, an important length scale for testing thin films, nanopillars, and nanoparticles.

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Friction and Mechanical Properties of AFM-Scan-Induced Ripples in Polymer Films

Frontiers in Mechanical Engineering ◽

10.3389/fmech.2021.672898 ◽

2021 ◽

Vol 7 ◽

Author(s):

Sebastian Friedrich ◽

Brunero Cappella

Keyword(s):

Mechanical Properties ◽

Polymer Films ◽

Mechanical Response ◽

Butyl Methacrylate ◽

Clear Correlation ◽

Contact Mode ◽

Cantilever Deflection ◽

Atomic Force ◽

Volume Measurements ◽

Force Volume

When compliant samples such as polymer films are scanned with an atomic force microscope (AFM) in contact mode, a periodic ripple pattern can be induced on the sample. In the present paper, friction and mechanical properties of such ripple structures on films of polystyrene (PS) and poly-n-(butyl methacrylate) (PnBMA) are investigated. Force volume measurements allow a quantitative analysis of the elastic moduli with nanometer resolution, showing a contrast in mechanical response between bundles and troughs. Additionally, analysis of the lateral cantilever deflection when scanning on pre-machined ripples shows a clear correlation between friction and the sample topography. Those results support the theory of crack propagation and the formation of voids as a mechanism responsible for the formation of ripples. This paper also shows the limits of the presented measuring methods for soft, compliant, and small structures. Special care must be taken to ensure that the analysis is not affected by artefacts.

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