Static analysis of rectangular nanoplates using trigonometric shear deformation theory based on nonlocal elasticity theory

• Mohammad Rahim Nami and
• Maziar Janghorban

Beilstein J. Nanotechnol. 2013, 4, 968–973, doi:10.3762/bjnano.4.109

• Mohammad Rahim Nami Maziar Janghorban School of Mechanical Engineering, Shiraz University, Shiraz, Iran 10.3762/bjnano.4.109 Abstract In this article, a new higher order shear deformation theory based on trigonometric shear deformation theory is developed. In order to consider the size effects

• , the nonlocal elasticity theory is used. An analytical method is adopted to solve the governing equations for static analysis of simply supported nanoplates. In the present theory, the transverse shear stresses satisfy the traction free boundary conditions of the rectangular plates and these stresses

• isotropic, orthotropic and anisotropic nanoplates. Keywords: nonlocal elasticity theory; rectangular nanoplate; static analysis; trigonometric shear deformation theory; Introduction In recent years, some new higher-order shear deformation theories have been adopted for studying macro structures such as

Dynamic nanoindentation by instrumented nanoindentation and force microscopy: a comparative review

• Sidney R. Cohen and
• Estelle Kalfon-Cohen

Beilstein J. Nanotechnol. 2013, 4, 815–833, doi:10.3762/bjnano.4.93

• -dependent shear modulus can vary with the ultimate force applied because of a deviation from linear viscoelastic behavior [30]. Because of their small size and the fine control over force and displacement, the point probes are particularly amenable to dynamic loading, in which a small modulation of several

• indenter. It has been noted that these relations hold strictly only for shear between two parallel plates and the application to nanoindentation experiments should be used with caution [75]. By using the dynamic model shown in Figure 4c, an analytical solution for the resulting displacement amplitude, h0

Size-dependent characteristics of electrostatically actuated fluid-conveying carbon nanotubes based on modified couple stress theory

• Mir Masoud Seyyed Fakhrabadi,
• Abbas Rastgoo and
• Mohammad Taghi Ahmadian

Beilstein J. Nanotechnol. 2013, 4, 771–780, doi:10.3762/bjnano.4.88

• Timoshenko beam model, which considers the rotational inertia and shear deformation, to investigate the effects of internal fluid flow on the transverse vibration [26]. They reported the natural frequencies of the system for different aspect ratios. Despite some studies concerning the effects of fluid flow

Deformation-induced grain growth and twinning in nanocrystalline palladium thin films

• Aaron Kobler,
• Jochen Lohmiller,
• Jonathan Schäfer,
• Michael Kerber,
• Anna Castrup,
• Ankush Kashiwar,
• Patric A. Gruber,
• Karsten Albe,
• Horst Hahn and
• Christian Kübel

Beilstein J. Nanotechnol. 2013, 4, 554–566, doi:10.3762/bjnano.4.64

• twinning/detwinning processes, stress-driven grain boundary migration and the formation of shear bands [4][5][6][7]. When studying the mechanical properties of nc metals and the associated deformation mechanisms, it is important to consider the preparation technique for the corresponding bulk nc metal

• Schmid-factor (the highest resolved shear stress). Here, randomly oriented twin boundaries can act as barriers to dislocation motion. In nano-twinned Pd, however, partial dislocations nucleate preferentially at twin boundaries. The twin boundaries then act as nucleation site and do not hinder successive

• for the remaining strain that does not come from dislocation/twin activity. Lohmiller et al. has already reported other mechanisms, such as GB shear and slip, as well as GB migration resulting in grain growth [28][45]. Conclusion NcPd thin films with a grain size of about 35 nm (plane view) were

Nanoglasses: a new kind of noncrystalline materials

• Herbert Gleiter

Beilstein J. Nanotechnol. 2013, 4, 517–533, doi:10.3762/bjnano.4.61

• enhanced free volume in shear bands [9][10], the average free volume content of a glass was found to increase [10][11] with increasing plastic deformation. However, despite the similarity between the microstructural features of a nanoglass produced by consolidating nanometer-sized glassy spheres and a

• nanoglass produced by introducing a high density of shear bands, the results of recent studies by molecular dynamics (MD) [12][13] and Mössbauer spectroscopy of a ball-milled melt-quenched Fe90Sc10 glassy ribbon and a Fe90Sc10 nanoglass suggest that the atomic structure of both kinds of nanoglass differ

• the nanoglass. In structurally homogenous ribbons, only one (or a few) shear bands are known to be nucleated under sufficiently high applied stresses. Plastic flow is limited to these shear bands and frequently results in fracture after an overall plastic deformation of less than 1%. However, in the

Molecular dynamics simulations of mechanical failure in polymorphic arrangements of amyloid fibrils containing structural defects

• Hlengisizwe Ndlovu,
• Alison E. Ashcroft,
• Sheena E. Radford and
• Sarah A. Harris

Beilstein J. Nanotechnol. 2013, 4, 429–440, doi:10.3762/bjnano.4.50

•  5. All three fibril polymorphs demonstrate an anisotropic response to mechanical probing. Similar mean peak forces are required to break the fibrils when the hydrogen-bond networks are probed (“shear” and “stretch”). There are however, very distinct responses in the SMD simulations that probe the

• demonstrates how the details imposed by polymorphic arrangements of the peptides in the fibril can determine the mechanical characteristics when a force is applied in a particular direction. Hydrogen-bond-network response: In the two pulling geometries (“shear” and “stretch”) that primarily interrogate the

• hydrogen-bond networks, similar mean peak forces were recorded for all three polymorphs. The stretch and shear simulations probe the interpeptide hydrogen networks in directions parallel and perpendicular to the fibril axis respectively. Figure 4 shows that pulling parallel to the hydrogen bond network

Optimal geometry for a quartz multipurpose SPM sensor

• Julian Stirling

Beilstein J. Nanotechnol. 2013, 4, 370–376, doi:10.3762/bjnano.4.43

• through an angle θ is given by where J and G are the torsion constant and shear modulus of the beam. In the case of a cantilever beam with a tip of length Ltip (measured from the central axis of the beam), the lateral displacement of the tip apex, Alat, is Ltipθ. Replacing the torque with the lateral tip

Plasticity of Cu nanoparticles: Dislocation-dendrite-induced strain hardening and a limit for displacive plasticity

• Antti Tolvanen and
• Karsten Albe

Beilstein J. Nanotechnol. 2013, 4, 173–179, doi:10.3762/bjnano.4.17

• high tensile strain rates by amorphisation [2] attributed to the kinetic energy of atoms exceeding the enthalpy of fusion [3]. Also, a near-surface nanodisturbance path, where, instead of conventional displacive plasticity, nanoscopic areas of plastic shear accommodate the stress, was reported for Ag

• File 2). We start our analysis by presenting the details of the displacive case. The maximum shear component (the maximum eigenvalue of the atomic stress tensor) in the initial system and at the onset of plasticity for different orientations for a 15.6 Å orifice is illustrated in Figure 2a–Figure 2c

• . For all the orientations, larger than average values of maximum shear are roughly localised on inverted spherical caps joining the edge of the circular orifice. The most extreme values of the atomic shear (parallel 2.4 MPa, orthogonal 2.3 MPa, and tilted 2.3 MPa) are almost the same and are located at

Functionalization of vertically aligned carbon nanotubes

• Eloise Van Hooijdonk,
• Carla Bittencourt,
• Rony Snyders and
• Jean-François Colomer

Beilstein J. Nanotechnol. 2013, 4, 129–152, doi:10.3762/bjnano.4.14

• remarkable self-cleaning abilities and the same properties, i.e., high shear and peeling forces (Figure 5) [64][65][66]. A further step in patterning VA-CNTs is the engineering of 3D-architectures. The formation of 3D-aligned carbon nanotube patterns is obtained by growing VA-MWCNTs with different lengths

Plasmonic oligomers in cylindrical vector light beams

• Mario Hentschel,
• Jens Dorfmüller,
• Harald Giessen,
• Sebastian Jäger,
• Andreas M. Kern,
• Kai Braun,
• Dai Zhang and
• Alfred J. Meixner

Beilstein J. Nanotechnol. 2013, 4, 57–65, doi:10.3762/bjnano.4.6

• microscopes, in combination with a home-built shear force AFM system and the use of sharp gold or glass-fiber tips, we operate a versatile scanning near-field optical microscope (SNOM) system. To measure the near field generated from the plasmonic oligomers, one single oligomer is placed inside the radially

• spatial arrangements imaginable. Schematic of two optical microscopic configurations using a parabolic mirror for focusing (a, adapted from [27]) and an objective lens for focusing (b). Shear-force SNOM configurations can be obtained by integrating a glass fiber (c) or a gold tip (d) to the confocal

Growth behaviour and mechanical properties of PLL/HA multilayer films studied by AFM

• Cagri Üzüm,
• Johannes Hellwig,
• Narayanan Madaboosi,
• Dmitry Volodkin and
• Regine von Klitzing

Beilstein J. Nanotechnol. 2012, 3, 778–788, doi:10.3762/bjnano.3.87

• exposed to a faster initial load and gives a hint about a non-Newtonian, shear-thinning behaviour [50]. Conclusion Mechanical properties of layer-by-layer assembled PLL/HA films with varied bilayer number were studied by scanning- and colloidal-probe atomic force microscopy. Detailed measurement and data

• . Both relaxation times decrease with increasing initial indentation velocity, suggesting a non-Newtonian, shear-thinning fluid character. Frequency-dependent AFM force [41] and quartz crystal microbalance measurements are planned for a better understanding of shear and friction effects on the mechanical

Effect of spherical Au nanoparticles on nanofriction and wear reduction in dry and liquid environments

• Dave Maharaj and
• Bharat Bhushan

Beilstein J. Nanotechnol. 2012, 3, 759–772, doi:10.3762/bjnano.3.85

• use with Au nanoparticles suspended in DI water. In addition to the fact that Au nanoparticles are provided already suspended in DI water, the low viscosity of water and its ability to provide a surface of low shear strength [35] for sliding, makes it a good candidate as an operating fluid. Water is

• contact pressure is reduced, leading to undeformed nanoparticles, which may roll between the surfaces. In water, the presence of a liquid film between the glass sphere and the silicon substrate provides an interface of low shear strength resulting in a lower coefficient of friction [35]. In addition

• contact pressure is reduced. This increases the chances of rolling for the undeformed nanoparticles as part of the friction-reduction mechanism. In the case of DI water without Au nanoparticles, a surface of low shear strength is obtained, which makes it easier for the sapphire ball to slide [35

Friction and durability of virgin and damaged skin with and without skin cream treatment using atomic force microscopy

• Bharat Bhushan,
• Si Chen and
• Shirong Ge

Beilstein J. Nanotechnol. 2012, 3, 731–746, doi:10.3762/bjnano.3.83

• . Liquid films (lipid and condensed water vapor) present on the skin surface reduce the interfacial shear strength leading to lower friction; however, a thicker film forms meniscus bridges at asperity contacts leading to higher friction [34][35][40]. Cream treatment moistens and softens the skin, which

• reformation of meniscus bridges. As the velocity increases, the meniscus bridges cannot be fully reformed, resulting in a drop in adhesive force and coefficient of friction. In the case of cream-treated skin, the skin cream is typically a shear-thinning fluid, and the viscosity decreases with the increasing

• shear rate leading to a decrease in the coefficient of friction [6][36]. Figure 6b shows the coefficient of friction as a function of normal load. The data shows that the friction for untreated skin samples first decreases then levels off, whereas, for the treated skin samples, it first decreased then

Assessing the plasmonics of gold nano-triangles with higher order laser modes

• Laura E. Hennemann,
• Andreas Kolloch,
• Andreas Kern,
• Josip Mihaljevic,
• Johannes Boneberg,
• Paul Leiderer,
• Alfred J. Meixner and
• Dai Zhang

Beilstein J. Nanotechnol. 2012, 3, 674–683, doi:10.3762/bjnano.3.77

• sample surface or parallel to it. The parameters varied in the Fischer patterns were the size of the triangles, their height and the substrate material (which was either silicon or glass). Using integrated shear-force microscope, we can collect the topography from the sample surface and compare the

• denominations). Not all combinations of sphere size and film thickness could be produced since the film thickness has to be distinctly smaller than the polystyrene spheres in order to obtain flat triangles. Thicker triangles would have the form of a truncated pyramid [26]. By shear-force topographical

• . Plenty of water was used to rinse the surface in order to get rid of the physically adsorbed multilayers. Results and Discussion 1. Topography Investigating the triangle arrays with the shear-force topographical method implemented in our setup [22] and SEM characterisations, we find well aligned

Repulsive bimodal atomic force microscopy on polymers

• Alexander M. Gigler,
• Christian Dietz,
• Maximilian Baumann,
• Nicolás F. Martinez,
• Ricardo García and
• Robert W. Stark

Beilstein J. Nanotechnol. 2012, 3, 456–463, doi:10.3762/bjnano.3.52

• reported for the same sample based on the results of a resonant shear force experiment [29]. Thus, when imaging flat samples that present such varying elastic properties, topographic contrast is enhanced by the repulsive-imaging process. At a given setpoint, the softer component is substantially deformed

Conducting composite materials from the biopolymer kappa-carrageenan and carbon nanotubes

• Ali Aldalbahi,
• Jin Chu,
• Peter Feng and
• Marc in het Panhuis

Beilstein J. Nanotechnol. 2012, 3, 415–427, doi:10.3762/bjnano.3.48

• flow-curve analysis. The viscosity was measured as a function of shear rate for KC solutions over a concentration range of 0.2–1.2% w/v at 21 °C (Figure 1a). All KC solutions displayed shear-thinning behaviour, i.e., decreasing viscosity (η) with increasing shear rate (). These flow curves were fitted

• to the well-known power-law model [44]: where K and n indicate the “consistency” and power-law index, respectively. Figure 1a shows that the viscosity of KC solutions increased with increasing concentration. For example, the apparent viscosity of the KC solution (at shear rate 21 s−1) increased from

• general [47]. Table 1 shows that KC solutions with a concentration <0.5% w/v have power-index values of ~0.8. However, for higher concentrations the solutions become more shear-thinning (n decreases), and thicker (K increases). Figure 1c shows a sharp increase in the apparent viscosity of the KC solution

Pulse-response measurement of frequency-resolved water dynamics on a hydrophilic surface using a Q-damped atomic force microscopy cantilever

• Masami Kageshima

Beilstein J. Nanotechnol. 2012, 3, 260–266, doi:10.3762/bjnano.3.29

• hydration layer and its shear property, and thus complicates the data analysis [19]. In the case of the pulse-response measurement, the effect of such a flow is expected to be weaker. In the present measurement the feedback loop for regulation of the tip–sample gap must be suspended during the period of

Manipulation of gold colloidal nanoparticles with atomic force microscopy in dynamic mode: influence of particle–substrate chemistry and morphology, and of operating conditions

• Samer Darwich,
• Karine Mougin,
• Akshata Rao,
• Enrico Gnecco,
• Shrisudersan Jayaraman and
• Hamidou Haidara

Beilstein J. Nanotechnol. 2011, 2, 85–98, doi:10.3762/bjnano.2.10

• intermittent tapping mode. The first mode used in AFM was the contact mode. Manipulation of large C60 islands on NaCl was performed by Lüthi et al. using contact AFM [11]. Even if the shear between islands and crystal surface can be derived from the frictional forces experienced by the AFM tip while scanning

• coefficient, τ is the shear strength, C the contact area, and α and β are the angles which are defined in Scheme 1. The subscripts tp and ps as of τ , C and μ represent the tip–particle and particle–substrate contacts, respectively. These results thus display the dependence of the movement of the particle on

Biomimetics inspired surfaces for drag reduction and oleophobicity/philicity

• Bharat Bhushan

Beilstein J. Nanotechnol. 2011, 2, 66–84, doi:10.3762/bjnano.2.9

• and hierarchical structure. Bechert et al. [19] showed that a turbulent boundary layer on the shark skin surface with ribs can help to reduce turbulent shear stress (also see Dean and Bhushan [22]). The results of experimental measurements on shark skin replica showed that a reduction of pressure drop

• generally known that surfaces with a streamlined body can produce dramatic reductions of the fluid pressure drag with only a slight increase in shear stress in air flow [60]. It is also known that as the Reynolds number increases, the pressure drop becomes very large, resulting in larger pressure drag. The

Switching adhesion forces by crossing the metal–insulator transition in Magnéli-type vanadium oxide crystals

• Bert Stegemann,
• Matthias Klemm,
• Siegfried Horn and
• Mathias Woydt

Beilstein J. Nanotechnol. 2011, 2, 59–65, doi:10.3762/bjnano.2.8

• general formulae (Ti,V)nO2n-1 or (W,Mo)nO3n-1 [4][5][6]. In a simplified way, the Magnèli phase structure can be derived from a perfect V2O5 crystal, which has one missing oxygen layer, i.e., the (121) plane, which is called the crystallographic shear (CS) plane and compensates for the non-stoichiometry

Defects in oxide surfaces studied by atomic force and scanning tunneling microscopy

• Thomas König,
• Georg H. Simon,
• Lars Heinke,
• Leonid Lichtenstein and
• Markus Heyde

Beilstein J. Nanotechnol. 2011, 2, 1–14, doi:10.3762/bjnano.2.1

• are decoupled from the microscope. The dual mode NC-AFM/STM sensor (Figure 2c) is situated on a tripod scanner opposite the sample. The scanner, in turn, is mounted onto a coarse approach unit (walker). The microscope stage is shown in Figure 2b. The coarse approach is driven by the shear stack piezos

• defects such as color centers, which are preferably situated at lower coordinated sites, are sketched as bright clouds. Experimental setup. a) Schematic of an Eigler-style bath cryostat. b) The walker unit is situated on three shear stack piezos for the coarse approach. The x, y and z piezos are used

• ) sensor carrier, (F) tuning fork assembly, (G) sample (not fully drawn), (H) sample holder (not fully drawn), (I) sample stage (not fully drawn), (J) microscope stage, (K) walker support and (L) shear stack piezos. The base plate has a diameter of 10 cm. c) The NC-AFM/STM tuning fork sensor is glued onto

The description of friction of silicon MEMS with surface roughness: virtues and limitations of a stochastic Prandtl–Tomlinson model and the simulation of vibration-induced friction reduction

• W. Merlijn van Spengen,
• Viviane Turq and
• Joost W. M. Frenken

Beilstein J. Nanotechnol. 2010, 1, 163–171, doi:10.3762/bjnano.1.20

• surface asperities [26]. The static shear strength itself is determined by OH-bridging forces between the surfaces, direct chemical Si–O–Si bonds between the surfaces (the rupturing of these bonds leads to wear of the surfaces in the long run), and/or possibly liquid water meniscus strain or even gluing

Review and outlook: from single nanoparticles to self-assembled monolayers and granular GMR sensors

• Alexander Weddemann,
• Inga Ennen,
• Anna Regtmeier,
• Camelia Albon,
• Annalena Wolff,
• Katrin Eckstädt,
• Nadine Mill,
• Michael K.-H. Peter,
• Jochen Mattay,
• Carolin Plattner,
• Norbert Sewald and
• Andreas Hütten

Beilstein J. Nanotechnol. 2010, 1, 75–93, doi:10.3762/bjnano.1.10

• order [49]. Additionally, friction and shear forces can arise between the particles on the one hand and between particles and substrate on the other hand [57][58]. In the latter case, the forces strongly depend on the surface properties such as structure and roughness. Thus, the choice of substrate is