Search results for "Modulus"
showing 10 items of 491 documents
Atlas for the properties of elemental two-dimensional metals
2018
Common two-dimensional (2D) materials have a layered three-dimensional (3D) structure with covalently bonded, atomically thin layers held together by weak van der Waals forces. However, in a recent transmission electron microscopy experiment, atomically thin 2D patches of iron were discovered inside a graphene nanopore. Motivated by this discovery, we perform a systematic density-functional study on atomically thin elemental 2D metal films, using 45 metals in three lattice structures. Cohesive energies, equilibrium distances, and bulk moduli in 2D are found to be linearly correlated to the corresponding 3D bulk properties, enabling the quick estimation of these values for a given 2D metal a…
Aluminum oxide from trimethylaluminum and water by atomic layer deposition:The temperature dependence of residual stress, elastic modulus, hardness a…
2014
Use of atomic layer deposition (ALD) in microelectromechanical systems (MEMS) has increased as ALD enables conformal growth on 3-dimensional structures at relatively low temperatures. For MEMS device design and fabrication, the understanding of stress and mechanical properties such as elastic modulus, hardness and adhesion of thin film is crucial. In this work a comprehensive characterization of the stress, elastic modulus, hardness and adhesion of ALD aluminum oxide (Al2O3) films grown at 110-300 C from trimethylaluminum and water is presented. Film stress was analyzed by wafer curvature measurements, elastic modulus by nanoindentation and surface-acoustic wave measurements, hardness by na…
Evaluation of Subgrade Resilient Modulus Predictive Model for Use in Mechanistic-Empirical Pavement Design Guide
2006
The characterization of unbound materials in the mechanistic–empirical pavement design guide (MEPDG), also known as the 2002 design guide, is reviewed, and this characterization is applied to Minnesota subgrades. The main emphasis is on the collection of k1-, k2-, and k3-parameters for Minnesota fine-grained soils and the procedure for the interpretation of the resilient modulus test to provide an input to the multilayer elastic theory (MLET) analysis (Level 2 input). This is an important aspect of adaptation of the MEPDG, because the guide recommends measurement of resilient moduli from laboratory testing, but the procedure does not specify how to interpret the test data to obtain an input …
Signal Restoration via a Splitting Approach
2012
International audience; In the present study, a novel signal restoration method from noisy data samples is presented and is termed as "signal split (SSplit)" approach. The new method utilizes Stein unbiased risk estimate estimator to split the signal, the Lipschitz exponents to identify noise elements and a heuristic approach for the signal reconstruction. However, unlike many noise removal techniques, the present method works only in the non-orthogonal domain. Signal restoration was performed on each individual part by finding the best compromise between the data samples and the smoothing criteria. Statistical results are quite promising and suggest better performance than the conventional…
Mappings of finite distortion: The sharp modulus of continuity
2003
We establish an essentially sharp modulus of continuity for mappings of subexponentially integrable distortion.
Tribological properties of commercial optical disks estimated from nanoindentation and scratch techniques
2007
Abstract The structure of optical disks is a complex superposition of several layers with different objectives. The most external layer is usually designed with a protective purpose. When the scratch of the substrate occurs, the optical properties of the device decrease inducing a deficiency in the storage or access of data. Nowadays, the latest commercial optical disks exhibit protective coatings made of polymeric materials (copolymers, and polymeric matrix composite materials). The efficiency of these layers depends on a combination of several mechanical properties like hardness and Young's modulus. In this work, a compositional and mechanical study was carried out on four commercial opti…
Generalized Fatigue Criterion of maximum shear and normal strains on the fracture plane for materials under multiaxial random loadings
1991
A generalized fatigue criterion for materials under multiaxial random loadings is presented. The criterion is based on the assumption that shear and normal strain on the expected fracture plane – shear strain in one direction on this plane is considered – determine the fracture plane. It has been shown that the well known fatigue criteria of maximum normal strain, maximum shear strain and the criterion of maximum shear and normal strains on the critical shear plane result from the newly formulated criterion.
Mechanical Properties of Pore-Spanning Lipid Bilayers Probed by Atomic Force Microscopy
2006
AbstractWe measure the elastic response of a free-standing lipid membrane to a local indentation by using an atomic force microscope. Starting point is a planar gold-coated alumina substrate with a chemisorbed 3-mercaptopropionic acid monolayer displaying circular pores of very well defined and tunable size, over which bilayers composed of N,N,-dimethyl-N,N,-dioctadecylammonium bromide or 1,2-dioleoyl-3-trimethylammonium-propane chloride were spread. Centrally indenting these “nanodrums” with an atomic force microscope tip yields force-indentation curves, which we quantitatively analyze by solving the corresponding shape equations of continuum curvature elasticity. Since the measured respon…
MR2524292 (2010f:26007): Kolyada, V. I.; Lind, M. On functions of bounded p-variation. J. Math. Anal. Appl. 356 (2009), no. 2, 582–604. (Reviewer: Lu…
2009
For p∈(1,+∞), let f∈Lp be a 1-periodic function on the real line, with the norm of f given by ∥f∥p=(∫10|f(x)|pdx)1/p. The Lp-modulus of continuity of f is defined by ω(f,δ)p=sup0≤h≤δ(∫10|f(x+h)−f(x)|pdx)1/p, 0≤δ≤1. A partition of period 1 (or simply a partition) is a set Π={x0,x1,…,xn} of points such that x0<x1<…<xn=x0+1. For a given partition Π={x0,x1,…,xn} let vp(f;Π)=(∑k=0n−1|f(xk+1)−f(xk)|p)1/p. The modulus of p-continuity of f is defined by ω1−1/p(f,δ)=sup∥Π∥≤δvp(f;Π), where the supremum is taken over all partitions Π such that ∥Π∥=maxk(xk+1−xk)≤δ. In this paper, improving a previous estimate given by A. P. Terehin [Mat. Zametki 2 (1967), 289--300; MR0223512 (36 #6560)], it is shown th…
Attendibilità dei modelli per la valutazione dei moduli elastici delle murature suggeriti dalle norme tecniche
2012
In this paper the results of an experimental investigation aimed to the assessment of Young moduli, rigidity moduli and other mechanical properties for different types of masonry are shown. The mechanical characteristics predicted by models proposed by some technical codes were compared against experimental data. This study was motivated by the suggestion of the Masonry Standards Joint Committee's (MSJC) code that, while proposing the use of such models, acknowledges the lack of testing in support of their validation. The experimental investigation has included compressive tests on components (blocks and mortar), diagonal compressive tests and ordinary compressive tests (orthogonally to bed…