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High frequency travelling surface acoustic waves for microparticle separation
Ghulam Destgeer,Anas Alazzam,성형진 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.9
In this study, we have demonstrated a particle separation device taking advantage of the high frequency sound waves. The sound waves, in the form of surface acoustic waves, are produced by an acoustofluidic platform built on top of a piezoelectric substrate bonded to a microfluidic channel. The particles’ mixture, pumped through the microchannel, is focused using a sheath fluid. A Travelling surface acoustic wave (TSAW), propagating normal to the flow, interacts with the particles and deflects them from their original path to induce size-based separation in a continuous flow. We initially started the experiment with 40 MHz TSAWs for deflecting 10 µm diameter polystyrene particles but failed. However, larger diameter particles (~ 30 µm) were successfully deflected from their streamlines and separated from the smaller particles (~ 10 µm) using TSAWs with 40 MHz frequency. The separation of smaller diameter particles (3, 5 and 7 µm) was also achieved using an order of magnitude higher-frequency (~ 133 MHz) TSAWs.
Abdur Rosyid,Bashar El-Khasawneh,Anas Alazzam 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.21 No.6
This paper presents the implementation of nonlinear least squares and iterative linear least squares algorithms for external kinematic calibration of a hybrid kinematics machine composed of two 3PRR planar parallel kinematics mechanisms by utilizing a laser tracker. First the hand-eye and robot-world transformations were obtained by a separable closed-form solution and refi ned by the nonlinear least squares. Subsequently, the geometric parameters of the machine’s mechanisms were estimated using the two algorithms. Due to the rank defi ciency, we implemented the nonlinear least squares algorithm through a subset selection approach in which we performed the estimation in two steps. We iterated the closed-form solution of the linear least squares until the solution converges to the actual values. We have shown that the nonlinear least squares algorithm successfully refi ned the hand-eye and robot-world transformations and outperformed the iterative linear squares algorithm in the estimation of the geometric parameters of the mechanisms.
Destgeer, Ghulam,Ha, Byung Hang,Park, Jinsoo,Jung, Jin Ho,Alazzam, Anas,Sung, Hyung Jin American Chemical Society 2015 ANALYTICAL CHEMISTRY - Vol.87 No.9
<P>We demonstrate a miniaturized acoustofluidic device composed of a pair of slanted interdigitated transducers (SIDTs) and a polydimethylsiloxane microchannel for achieving size-selective separation and exchange of medium around polystyrene particles in a continuous, label-free, and contactless fashion. The SIDTs, deposited parallel to each other, produce tunable traveling surface acoustic waves (TSAWs) at desired locations, which, in turn, yield an anechoic corner inside the microchannel that is used to selectively deflect particles of choice from their streamlines. The TSAWs with frequency <I>f</I><SUB>R</SUB> originating from the right SIDT and propagating left toward the microchannel normal to the fluid flow direction, laterally deflect larger particles with diameter <I>d</I><SUB>1</SUB> from the hydrodynamically focused sample fluid that carries other particles as well with diameters <I>d</I><SUB>2</SUB> and <I>d</I><SUB>3</SUB>, such that <I>d</I><SUB>1</SUB> > <I>d</I><SUB>2</SUB> > <I>d</I><SUB>3</SUB>. The deflected particles (<I>d</I><SUB>1</SUB>) are pushed into the top-left corner of the microchannel. Downstream, the TSAWs with frequency <I>f</I><SUB>L</SUB>, such that <I>f</I><SUB>L</SUB> > <I>f</I><SUB>R</SUB>, disseminating from the left SIDT, deflect the medium-sized particles (<I>d</I><SUB>2</SUB>) rightward, leaving behind the larger particles (<I>d</I><SUB>1</SUB>) unaffected in the top-left anechoic corner and the smaller particles (<I>d</I><SUB>3</SUB>) in the middle of the microchannel, thereby achieving particle separation. A particle not present in the anechoic corner could be deflected rightward to realize twice the medium exchange. In this work, the three-way separation of polystyrene particles with diameters of 3, 4.2, and 5 μm and 3, 5, and 7 μm is achieved using two separate devices. Moreover, these devices are used to demonstrate multimedium exchange around polystyrene particles ∼5 μm and 7 μm in diameter.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancham/2015/ancham.2015.87.issue-9/acs.analchem.5b00525/production/images/medium/ac-2015-00525e_0004.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ac5b00525'>ACS Electronic Supporting Info</A></P>