Browsing by Subject "Particle tracking"

Now showing 1 - 4 of 4

Open Access
Intracavity optical trapping with ytterbium doped fiber
(SPIE, 2013) Laser, R.; Sayed, R.; Kalantarifard, Fatemeh; Elahi P.; İlday, F. Ömer; Volpe, Giovanni; Marago O.M.
We propose a novel approach for trapping micron-sized particles and living cells based on optical feedback. This approach can be implemented at low numerical aperture (NA=0.5, 20X) and long working distance. In this configuration, an optical tweezers is constructed inside a ring cavity fiber laser and the optical feedback in the ring cavity is controlled by the light scattered from a trapped particle. In particular, once the particle is trapped, the laser operation, optical feedback and intracavity power are affected by the particle motion. We demonstrate that using this configuration is possible to stably hold micron-sized particles and single living cells in the focal spot of the laser beam. The calibration of the optical forces is achieved by tracking the Brownian motion of a trapped particle or cell and analysing its position distribution. © 2013 SPIE.
Open Access
A multi-domain direct boundary element formulation for particulate flow in microchannels
(Elsevier Ltd, 2021-11-01) Topuz, Alper; Baranoğlu, B.; Çetin, Barbaros
In the present study, a multi-domain boundary element formulation is developed for high surface-area-to-volume ratio problems (i.e. particulate flow in high aspect ratio microfluidic channels, in a porous medium or in microfluidic devices with repetitive structures). The solution domain is decomposed into subdomains and the variable condensation technique is implemented. The solution matrices are built for each subdomain, and the matrices are updated at each time step only for the subdomains in which the particles move at each time step. Ghost domains, which are fictitious domains encapsulating the interfaces between the subdomains, are also introduced in the formulation to treat the particles crossing the interfaces between the subdomains. The formulation reveals that the computation of the subdomain matrices is further simplified for solution domains composed of periodic structures. The results of our study revealed that speed-up values as high as 50 is achievable with the current formulation.
Open Access
A multi-domain direct boundary element formulation for particulate flow in microchannels
(2021-08) Topuz, Alper
In the present study, a multi-domain boundary element formulation is developed for high surface-area-to-volume ratio problems (i.e. particulate ﬂow in high as-pect ratio microﬂuidic channels, in a porous medium or in microﬂuidic devices with repetitive structures). The solution domain is decomposed into subdomains and the variable condensation technique is implemented. The solution matrices are built for each subdomain, and the matrices are updated at each time step only for the subdomains in which the particles move at each time step. Ghost domains, which are ﬁctitious domains encapsulating the interfaces between the subdomains, are also introduced in the formulation to treat the particles cross-ing the interfaces between the subdomains. The formulation reveals that the computation of the subdomain matrices is further simpliﬁed for solution domains composed of periodic structures. The results of our study revealed that speed-up values as high as 50 for 2D structures and 80 for 3D structures is achievable with the current formulation.
Open Access
A parallel boundary element formulation for tracking multiple particle trajectories in Stoke's flow for microfluidic applications
(Tech Science Press, 2015) Karakaya, Z.; Baranoʇlu, B.; Çetin B.; Yazici, A.
A new formulation for tracking multiple particles in slow viscous flow for microfluidic applications is presented. The method employs the manipulation of the boundary element matrices so that finally a system of equations is obtained relating the rigid body velocities of the particle to the forces applied on the particle. The formulation is specially designed for particle trajectory tracking and involves successive matrix multiplications for which SMP (Symmetric multiprocessing) parallelisation is applied. It is observed that present formulation offers an efficient numerical model to be used for particle tracking and can easily be extended for multiphysics simulations in which several physics involved. Copyright © 2015 Tech Science Press.