Open Access. Powered by Scholars. Published by Universities.®
- Keyword
-
- Atomic force microscopy (3)
- Attractors (2)
- Liquid surfaces (2)
- Periodic solutions (2)
- Surface dynamics (2)
-
- Adhesion (1)
- Atom surface interactions (1)
- Coffee ring pattern (1)
- Colloidal drops (1)
- DVLO interaction (1)
- Hydrophilic interactions (1)
- Hydrophobic interactions (1)
- Lagrangian framework (1)
- Marangoni stresses (1)
- Microscopy (1)
- Nucleation (1)
- Numerical solutions (1)
- Profilmoetry (1)
- Rheology and fluid dynamics (1)
- Surface finishing (1)
- Surface patterning (1)
Articles 1 - 9 of 9
Full-Text Articles in Mechanical Engineering
Mercuric Ionic Liquids: [Cnmim][Hgx3], Where N = 3, 4 And X = Cl, Br, Bert Mallick, Andreas Metlen, Mark Nieuwenhuyzen, Robin D. Rogers, Anja V. Mudring
Mercuric Ionic Liquids: [Cnmim][Hgx3], Where N = 3, 4 And X = Cl, Br, Bert Mallick, Andreas Metlen, Mark Nieuwenhuyzen, Robin D. Rogers, Anja V. Mudring
Anja V. Mudring
A series of mercury(II) ionic liquids, [Cnmim][HgX3], where [Cnmim] = n-alkyl-3-methylimidazolium with n = 3, 4 and X = Cl, Br, have been synthesized following two different synthetic approaches, and structurally characterized by means of single-crystal X-ray structure analysis ([C3mim][HgCl3] (1), Cc (No. 9), Z = 4, a = 16.831(4) Å, b = 10.7496(15) Å, c = 7.4661(14) Å, β = 105.97(2)°, V = 1298.7(4) Å3 at 298 K; [C4mim][HgCl3] (2), Cc (No. 9), Z = 4, a = 17.3178(28) Å, b = 10.7410(15) Å, c = 7.4706(14) Å, β = 105.590(13)°, V = 1338.5(4) Å3 at 170 K; [C3mim][HgBr3] …
Manufacturing Self-Assembled Coatings Of Micro- And Nano-Particles By Controlled Evaporation Of Drops And Thin Films, Junfeng Xiao, Rajneesh Bhardwaj, Daniel Attinger
Manufacturing Self-Assembled Coatings Of Micro- And Nano-Particles By Controlled Evaporation Of Drops And Thin Films, Junfeng Xiao, Rajneesh Bhardwaj, Daniel Attinger
Daniel Attinger
The engineered deposition of self-assembled coatings of micro- and nano-particles on solid surfaces has applications in photonic crystals, optoelectronic devices, sensors, waveguides and antireflective coatings. Besides lithographic, etching or vapor deposition methods, these coatings can be self-assembled on small (
Do Surfaces With Mixed Hydrophilic And Hydrophobic Areas Enhance Pool Boiling?, Amy Rachel Betz, Jie Xu, Huihe Qiu, Daniel Attinger
Do Surfaces With Mixed Hydrophilic And Hydrophobic Areas Enhance Pool Boiling?, Amy Rachel Betz, Jie Xu, Huihe Qiu, Daniel Attinger
Daniel Attinger
We demonstrate that smooth and flat surfaces combining hydrophilic and hydrophobicpatterns improve pool boiling performance. Compared to a hydrophilicsurface with 7° wetting angle, the measured critical heat flux and heat transfer coefficients of the enhanced surfaces are, up to respectively, 65% and 100% higher. Different networks combining hydrophilic and hydrophobic regions are characterized. While all tested networks enhance the heat transfer coefficient, large enhancements of critical heat flux are typically found for hydrophilic networks featuring hydrophobic islands. Hydrophilic networks indeed are shown to prevent the formation of an insulating vapor layer.
Self-Assembly Of Colloidal Particles From Evaporating Droplets: Role Of Dlvo Interactions And Proposition Of A Phase Diagram, Rajneesh Bhardwaj, Xiaohua Fang, Ponisseril Somasundaran, Daniel Attinger
Self-Assembly Of Colloidal Particles From Evaporating Droplets: Role Of Dlvo Interactions And Proposition Of A Phase Diagram, Rajneesh Bhardwaj, Xiaohua Fang, Ponisseril Somasundaran, Daniel Attinger
Daniel Attinger
The shape of deposits obtained from drying drops containing colloidal particles matters for technologies such as inkjet printing, microelectronics, and bioassay manufacturing. In this work, the formation of deposits during the drying of nanoliter drops containing colloidal particles is investigated experimentally with microscopy and profilometry, and theoretically with an in-house finite-element code. The system studied involves aqueous drops containing titania nanoparticles evaporating on a glass substrate. Deposit shapes from spotted drops at different pH values are measured using a laser profilometer. Our results show that the pH of the solution influences the dried deposit pattern, which can be ring-like or …
Dynamic Reversibility Of Hydrodynamic Focusing For Recycling Sheath Fluid, Nicole N. Hashemi, Peter B. Howell Jr., Jeffrey S. Erickson, Joel P. Golden, Francis S. Ligler
Dynamic Reversibility Of Hydrodynamic Focusing For Recycling Sheath Fluid, Nicole N. Hashemi, Peter B. Howell Jr., Jeffrey S. Erickson, Joel P. Golden, Francis S. Ligler
Nastaran Hashemi
The phenomenon of "unmixing" has been demonstrated in microfluidic mixers, but here we manipulate laminar flow streams back to their original positions in order to extend the operational utility of an analytical device where no mixing is desired. Using grooves in the channel wall, we passively focus a sample stream with two sheath streams to center it in a microchannel for optical analysis. Even though the sample stream is completely surrounded by sheath fluid, reversing the orientation of the grooves in the channel walls returns the sample stream to its original position with respect to the sheath streams. We demonstrate …
Pattern Formation During The Evaporation Of A Colloidal Nanoliter Drop: A Numerical And Experimental Study, Rajneesh Bhardwaj, Xiaohua Fang, Daniel Attinger
Pattern Formation During The Evaporation Of A Colloidal Nanoliter Drop: A Numerical And Experimental Study, Rajneesh Bhardwaj, Xiaohua Fang, Daniel Attinger
Daniel Attinger
An efficient way to precisely pattern particles on solid surfaces is to dispense and evaporate colloidal drops, as for bioassays. The dried deposits often exhibit complex structures exemplified by the coffee ring pattern, where most particles have accumulated at the periphery of the deposit. In this work, the formation of deposits during the drying of nanoliter colloidal drops on a flat substrate is investigated numerically and experimentally. A finite-element numerical model is developed that solves the Navier–Stokes, heat and mass transport equations in a Lagrangian framework. The diffusion of vapor in the atmosphere is solved numerically, providing an exact boundary …
Basins Of Attraction Of Tapping Mode Atomic Force Microscopy With Capillary Force Interactions, Nicole N. Hashemi, Reza Montazami
Basins Of Attraction Of Tapping Mode Atomic Force Microscopy With Capillary Force Interactions, Nicole N. Hashemi, Reza Montazami
Nastaran Hashemi
We perform a large number of simulations over a wide range of system parameters to approximate the basins of attraction of steady oscillating solutions. We find that the basins of attraction vary as a function of system parameters and initial conditions. For large equilibrium separations, the basin of attraction is dominated by the low-amplitude solution. The location of the fixed point is shifted toward the higher values of instantaneous displacement and velocity for larger equilibrium separations. We show that the basin of attraction in the neighborhood of the fixed point is dominated by low-amplitude solutions as relative humidity is increased.
The Nonlinear Dynamics Of Tapping Mode Atomic Force Microscopy With Capillary Force Interactions, Nicole N. Hashemi, H. Dankowicz, M.R. Paul
The Nonlinear Dynamics Of Tapping Mode Atomic Force Microscopy With Capillary Force Interactions, Nicole N. Hashemi, H. Dankowicz, M.R. Paul
Nastaran Hashemi
We study the nonlinear dynamics of a tapping mode atomic force microscope with tip-surface interactions that include attractive, repulsive, and capillary force contributions using numerical techniques tailored for hybrid or discontinuous dynamical systems that include forward-time simulation with event handling and numerical pseudo-arclength continuation. We find four branches of periodic solutions that are separated by windows of complex and irregular dynamics. The branches of periodic solutions end where the cantilever comes into grazing contact with event surfaces in state space, corresponding to the onset of capillary interactions and the onset of repulsive forces associated with contact. These windows of irregular …
The Dissipated Power In Atomic Force Microscopy Due To Interactions With A Capillary Fluid Layer, Nicole N. Hashemi, M.R. Paul, H. Dankowicz, W. Jhe
The Dissipated Power In Atomic Force Microscopy Due To Interactions With A Capillary Fluid Layer, Nicole N. Hashemi, M.R. Paul, H. Dankowicz, W. Jhe
Nastaran Hashemi
We study the power dissipated by the tip of an oscillating micron-scale cantilever as it interacts with a sample using a nonlinear model of the tip-surface force interactions that includes attractive, adhesive, repulsive, and capillary contributions. The force interactions of the model are entirely conservative and the dissipated power is due to the hysteretic nature of the interaction with the capillary fluid layer. Using numerical techniques tailored for nonlinear and discontinuous dynamical systems we compute the exact dissipated power over a range of experimentally relevant conditions. This is accomplished by computing precisely the fraction of oscillations that break the fluid …