Search results for "elastic modulus"
showing 10 items of 189 documents
The effects of the additive of Eu ions on elastic and electric properties of BaTiO3ceramics
2016
ABSTRACTThe BaTiO3 and BaTiO3+X%wt.Eu2O3 (X = 1, 2, 3) ceramics were prepared by a solid phase reaction. The structural and morphology studies were carried out by means of an X-ray diffraction technique and scanning electron microscopy, respectively. Elastic moduli were determined with the use of an ultrasonic method. The dielectric permittivity (ϵ′) and tanδ as a function of composition and temperature were investigated. The increasing concentration of Eu ions leads to a slight shift of the Curie temperature and changes the characteristics of ϵ′ and tanδ. The structural, mechanical and dielectric properties of the BTEX ceramics were discussed in terms of microstructure and dopants contents.
Investigation of mechanical and electrical properties of Li doped sodium niobate ceramic system
2016
ABSTRACTThe Na0.96Li0.04NbO3 ceramic solid solution was prepared by means of a two-stage hot-pressing technology. The X-ray diffraction analysis showed the formation of a single perovskite phase with an orthorhombic symmetry in the investigated composition. The microstructure and EDS measurements were performed. They confirmed the high purity and the expected qualitative composition. A good homogeneity of the microstructures and a small degree of porosity were observed. The elastic modulus (the Young's modulus E, shear modulus G, and Poisson's ratio ν) of Na0.96Li0.04NbO3 were determined with the use of an ultrasonic method. The electrical properties of Na0.96Li0.04NbO3 ceramics were invest…
Mechanical characterisation of pentagonal gold nanowires in three different test configurations: A comparative study.
2019
Abstract Mechanical characterisation of individual nanostructures is a challenging task and can greatly benefit from the utilisation of several alternative approaches to increase the reliability of results. In the present work, we have measured and compared the elastic modulus of five-fold twinned gold nanowires (NWs) with atomic force microscopy (AFM) indentation in three different test configurations: three-point bending with fixed ends, three-point bending with free ends and cantilevered-beam bending. The free-ends condition was realized by introducing a novel approach where the NW is placed diagonally inside an inverted pyramid chemically etched in a silicon wafer. In addition, all thre…
Determination of elastoplastic properties of TiO2 thin films deposited on dual phase stainless steel using nanoindentation tests
2010
International audience; In recent years, the extraction of mechanical behaviour of thin films by nanoindentation using sharp indenter geometry has been extensively studied. This work investigates the mechanical properties of TiO2 thin film (1 µm thickness) deposited by spin coating on dual phase Duplex stainless steel and glass substrates. Experiments are carried out with different sharp triangular pyramids (a Cube corner and a Berkovich indenter) using a commercial Nano Indenter® XP apparatus. The substrate effect has been counteracted and an inverse method proposed in literature for bulk material has been adapted to assess the elastoplastic parameters of the tested thin film directly from…
Atomic layer deposition of aluminum oxide on modified steel substrates
2016
Abstract Al 2 O 3 thin films were grown by atomic layer deposition to thicknesses ranging from 10 to 90 nm on flexible steel substrates at 300 °C using Al(CH 3 ) 3 and H 2 O as precursors. The films grown to thicknesses 9–90 nm covered the rough steel surfaces uniformly, allowing reliable evaluation of their dielectric permittivity and electrical current densities with appreciable contact yield. Mechanical behavior of the coatings was evaluated by nanoindentation. The maximum hardness values of the Al 2 O 3 films on steel reached 12 GPa and the elastic modulus exceeded 280 GPa.
Resveratrol-Induced Temporal Variation in the Mechanical Properties of MCF-7 Breast Cancer Cells Investigated by Atomic Force Microscopy
2019
Atomic force microscopy (AFM) combined with fluorescence microscopy has been used to quantify cytomechanical modifications induced by resveratrol (at a fixed concentration of 50 µ
The effects of fractional CO2 laser, Nano-hydroxyapatite and MI paste on mechanical properties of bovine enamel after bleaching
2017
Background This study investigated the effect of post bleaching treatments to the change of enamel elastic modulus and microhardness after dental bleaching in- vitro. Material and Methods Fifty bovine incisor slab were randomly assigned into five groups (n=10). The samples were bleached for three times; 20 minutes each time, by 40% hydrogen peroxide. Next it was applied fractional CO2 laser for two minutes, Nano- hydroxy apatite (N-HA) and MI-paste for 7 days and 2 minutes per day. The sound enamel and bleached teeth without post treatment remained as control groups. The elastic modulus and microhardness were measured at three times; 24 hours, 1 and 2 months. Data were statistically analyze…
COMBINATION OF ARGAN OIL AND PHOSPHOLIPIDS FOR THE DEVELOPMENT OF AN EFFECTIVE LIPOSOME-LIKE FORMULATION ABLE TO IMPROVE SKIN HYDRATION AND ALLANTOIN…
2016
Allantoin is traditionally employed in the treatment of skin ulcers and hypertrophic scars. In the present work, to improve its local deposition in the skin and deeper tissues, allantoin was incorporated in conventional liposomes and in new argan oil enriched liposomes. In both cases, obtained vesicles were unilamellar, as confirmed by cryo-TEM observation, but the addition of argan oil allowed a slight increase of the mean diameter (∼130nm versus ∼85nm). The formulations, especially those containing argan oil, favoured the allantoin accumulation in the skin, in particular in the dermis (∼8.7μg/cm(2)), and its permeation through the skin (∼33μg/cm(2)). The performances of vesicles as skin d…
InBO3 and ScBO3 at high pressures: an ab initio study of elastic and thermodynamic properties
2016
We have theoretically investigated the elastic properties of calcite-type orthoborates ABO(3) (A= Sc and In) at high pressure by means of ab initio total-energy calculations. From the elastic stiffness coefficients, we have obtained the elastic moduli (B, G and E), Poisson's ratio (nu), B/G ratio, universal elastic anisotropy index (A(U)), Vickers hardness, and sound wave velocities for both orthoborates. Our simulations show that both borates are more resistive to volume compression than to shear deformation (B > G). Both compounds are ductile and become more ductile, with an increasing elastic anisotropy, as pressure increases. We have also calculated some thermodynamic properties, like D…
Age-related muscle activation profiles and joint stiffness regulation in repetitive hopping
2011
Abstract It is well documented that increasing effort during exercise is characterized by an increase in electromyographic activity of the relevant muscles. How aging influences this relationship is a matter of great interest. In the present study, nine young and 24 elderly subjects did repetitive hopping with maximal effort as well as with 50%, 65%, 75% and 90% intensities. During hopping joint kinematics were measured together with electromyographic activity (EMG) from the soleus, gastrocnemius medialis, gastrocnemius lateralis and tibialis anterior muscles. The results showed that agonist activation increased in both age groups with increasing intensity. The highest jumping efficiency (E…