Search results for "Tact"
showing 10 items of 1313 documents
Biosilica electrically-insulating layers by soft lithography-assisted biomineralisation with recombinant silicatein.
2011
On the Elastic Behavior of a Cross-Ply Composite Pin-Joint with Clearance Fits
1999
The effect of pin/hole clearance fits on the elastic membranal behavior of a cross-ply fiber glass-reinforced epoxy laminate plate loaded in tension through a pin is examined by a finite element nonlinear contact analysis. No a priori assumption is made on the distribution of the contact pressure on the surface of the hole. Friction effects are not included. The numerical results correlate well with Hertzian theory of contact. It is demonstrated that clearance increases the peak compressive stress in the plate up to a factor of 3000% with respect to the perfect-fit case. Clearance also shifts the location of the peak tensile stress towards the pin/hole contact arc and decreases its magnitu…
On the Effect of Interference Fits in Composite Pin-Joints
1999
The Finite Element Method is used to determine the effect of pin/hole interference fits on the elastic membranal behavior of an orthotropic plate loaded in tension through a pin. A complete contact analysis is performed to handle the nonlinear contact problem. The study encompasses two levels of interference fits, two degrees of anisotropy of the plate, and two load levels. Friction effects are not included. Experimental results from Digital Speckle Pattern Interferometry are also presented. It is shown that the stress changes in the plate vary linearly with load when no pin/plate separation occurs. It is also shown that interference fits can have beneficial effects on the static and fatig…
A Study on the Effects of Clearance and Interference Fits in a Pin-Loaded Cross-Ply FGRP Laminate
1998
The elastic behavior of a cross-ply fiber glass-reinforced epoxy laminate loaded in tension through a pin fitted with clearance and interference is examined. A nonlinear contact analysis using the Finite Element Method and an experimental study by Speckle Interferometry are performed, showing fairly good correlation. An interesting comparison is performed between FEM results and Hertzian contact theory. Major conclusions are: (I) clearance causes high compressive stress in the bearing area, and does not influence the peak tensile stress; (2) interference has beneficial effects on the joint, as (a) it lowers the peak circumferential stress, and (b) it decreases the change of stress due to t…
Entrapment of charged, nonwetting colloids near oil-water interfaces.
2007
Charged, nonwetting colloids with a contact angle $\ensuremath{\theta}=180\ifmmode^\circ\else\textdegree\fi{}$ are attracted to an oil-water interface due to image charge forces. Near the interface, the attractive image charge forces are balanced by repulsive van der Waals forces, and thus the colloids are trapped at a finite distance from the interface. Electrostatic and van der Waals pressure lead to a deformation of the interface in the equilibrium state. For parameters relevant to experiment, however, the effects of the deformed interface are negligible and thus the mutual interactions of such interfacially trapped colloids should be well characterized by electrostatic dipole repulsions.
Some aspects of formation and tribological properties of silver nanodumbbells.
2013
In this paper, metal nanodumbbells (NDs) formed by laser-induced melting of Ag nanowires (NWs) on an oxidized silicon substrate and their tribological properties are investigated. The mechanism of ND formation is proposed and illustrated with finite element method simulations. Tribological measurements consist in controllable real-time manipulation of NDs inside a scanning electron microscope (SEM) with simultaneous force registration. The geometry of NDs enables to distinguish between different types of motion, i.e. rolling, sliding and rotation. Real contact areas are calculated from the traces left after the displacement of NDs and compared to the contact areas predicted by the contact m…
Carrier transport mechanism in the SnO(2):F/p-type a-Si:H heterojunction
2011
We characterize SnO(2):F/p-type a-Si:H/Mo structures by current-voltage (I-V) and capacitance-voltage (C-V) measurements at different temperatures to determine the transport mechanism in the SnO2:F/p-type a-Si:H heterojunction. The experimental I-V curves of these structures, almost symmetric around the origin, are ohmic for vertical bar V vertical bar< 0:1 V and have a super-linear behavior (power law) for vertical bar V vertical bar < 0:1 V. The structure can be modeled as two diodes back to back connected so that the main current transport mechanisms are due to the reverse current of the diodes. To explain the measured C-V curves, the capacitance of the heterostructure is modeled as the …
Graphene and graphene oxide on Ir(111) are transparent to wetting but not to icing
2021
Anti-icing coatings reduce the freezing onset temperature for water by changing the chemical and physical environment at the water-substrate interface to prevent ice nucleation and growth. Graphene oxide has several attributes that make it attractive as an anti-icing coating and it has been theoretically predicted that graphene oxide has a lower freezing onset temperature than pristine graphene. Here, we test this hypothesis using carefully prepared, well-characterized graphene oxide substrates. We compare the water contact angle for graphene and graphene oxide coatings, both prepared on iridium(111) surfaces. The results show both materials to be transparent to wetting, but indicate a lowe…
Improved hydrophobicity of inorganic–organic hybrid mesoporous silica with cage-like pores
2013
International audience; Hydrophobic ordered mesoporous silica particles with cage-like pores (SBA-1 type) were prepared through co-condensation of phenyltriethoxysilane (PhTES) and tetraethylorthosilicate (TEOS) at different TEOS/PhTES molar ratios. It is shown that the hydrophobic character of the particles is enhanced by increasing the phenyl loading (decreasing the TEOS/PhTES molar ratio) and that it could be further enhanced by subsequent trimethylsilyl (TMS) grafting on remaining silanol groups (TMS-PhSBA-1 sample). This increase of hydrophobicity has been evidenced on the internal surface (mesoporosity) of the particles using water adsorption and, on the external surface of the partic…
Series expansion for the effective conductivity of a periodic dilute composite with thermal resistance at the two-phase interface
2019
We study the asymptotic behavior of the effective thermal conductivity of a periodic two-phase dilute composite obtained by introducing into an infinite homogeneous matrix a periodic set of inclusions of a different material, each of them of size proportional to a positive parameter ?. We assume that the normal component of the heat flux is continuous at the two-phase interface, while we impose that the temperature field displays a jump proportional to the normal heat flux. For ? small, we prove that the effective conductivity can be represented as a convergent power series in ? and we determine the coefficients in terms of the solutions of explicit systems of integral equations.