Arturo Villegas V - Academia.edu (original) (raw)

Papers by Arturo Villegas V

Research paper thumbnail of Identification of Model Particle Mixtures Using Machine-Learning-Assisted Laser Diffraction

Photonics, 2022

We put forward and demonstrate with model particles a smart laser-diffraction analysis technique ... more We put forward and demonstrate with model particles a smart laser-diffraction analysis technique aimed at particle mixture identification. We retrieve information about the size, shape, and ratio concentration of two-component heterogeneous model particle mixtures with an accuracy above 92%. We verify the method by detecting arrays of randomly located model particles with different shapes generated with a Digital Micromirror Device (DMD). In contrast to commonly-used laser diffraction schemes—In which a large number of detectors are needed—Our machine-learning-assisted protocol makes use of a single far-field diffraction pattern contained within a small angle (∼0.26°) around the light propagation axis. Therefore, it does not need to analyze particles of the array individually to obtain relevant information about the ensemble, it retrieves all information from the diffraction pattern generated by the whole array of particles, which simplifies considerably its implementation in compar...

Research paper thumbnail of Characterization of the startup transient electrokinetic flow in rectangular channels of arbitrary dimensions, zeta potential distribution, and time-varying pressure gradient

Electrophoresis, Jan 11, 2014

The solution to the startup transient electroosmotic flow in an arbitrary rectangular micro-chann... more The solution to the startup transient electroosmotic flow in an arbitrary rectangular micro-channel is derived analytically and validated experimentally. This full two dimensional transient solution describes the evolution of the flow through five distinct periods until reaching a final steady state. The derived analytical velocity solution is validated experimentally for different channel sizes and aspect ratios under time-varying pressure gradients. The experiments used a Time Resolved Micro Particle Image Velocimetry technique, TR-μPIV, to calculate the startup transient velocity profiles. The measurements captured the effect of time-varying pressure gradient fields derived in the analytical solutions. This is tested by using small reservoirs at both ends of the channel which allowed a time-varying pressure gradient to develop with a time scale on the order of the transient electroosmotic flow. Results showed that under these common conditions, the effect of the pressure build up...

Research paper thumbnail of Esplenectomia en el tratamiento del linfoma primario de bazo

Rev Invest Clin, Jun 1, 1986

Research paper thumbnail of Instantaneous Aerodynamic Load Calculations in Rotating Airfoils From Time Resolved PIV Measurements at Low Reynolds Number

Volume 7B: Fluids Engineering Systems and Technologies, 2013

ABSTRACT The time-resolved evolution of the instantaneous pressure fields and aerodynamic loads a... more ABSTRACT The time-resolved evolution of the instantaneous pressure fields and aerodynamic loads are obtained for rotating airfoils. This method allows evaluating the fluctuations in the instantaneous aerodynamic loads which cannot be evaluated with averaging methods. It also has the ability of capturing high temporal variations such as vortex shedding in the wake of the rotating blade. Briefly, this method obtains the velocity field from time-resolved particle image velocimetry TR-PIV. This is used to calculate the pressure field around the turbine from the Poisson pressure equation. Then, the forces are obtained using the integral momentum equation in a stationary reference frame. These experimental aerodynamic loads are compared to theoretical predictions from the Blade Element Momentum theory (BEM). Accurately determining instantaneous forces in turbines is needed for safety and understanding of their full range of operation. The standard deviation of the instantaneous forces establishes the limits of the forces expected on the turbine. The uncertainty in the measurements is calculated. The method presented may be used to measure unsteady forces in rotating airfoils, providing useful information not just for computational studies, but also for aerodynamics, material and structural optimization and safety purposes.

Research paper thumbnail of Spatial spectroscopy for high resolution imaging

EPJ Web of Conferences

Quantum estimation theory provides bounds for the precision in the estimation of a set of paramet... more Quantum estimation theory provides bounds for the precision in the estimation of a set of parameters that characterize a system. Two questions naturally arise: Is any of these bounds tight? And if this is the case, what type of measurements can attain such a limit? In this work we show that for phase objects, it is possible to find a tight resolution bound. Moreover one can find a set of spatial modes whose detection provides an optimal estimation of the complete set of parameters for which we propose a homodyne detection scheme. We call this method spatial spectroscopy since it mimics in the spatial domain what conventional spectroscopy methods do in the frequency domain employing many frequencies (hyperspectral imaging).

Research paper thumbnail of Spatial spectroscopy for high resolution imaging

EPJ Web of Conferences

Quantum estimation theory provides bounds for the precision in the estimation of a set of paramet... more Quantum estimation theory provides bounds for the precision in the estimation of a set of parameters that characterize a system. Two questions naturally arise: Is any of these bounds tight? And if this is the case, what type of measurements can attain such a limit? In this work we show that for phase objects, it is possible to find a tight resolution bound. Moreover one can find a set of spatial modes whose detection provides an optimal estimation of the complete set of parameters for which we propose a homodyne detection scheme. We call this method spatial spectroscopy since it mimics in the spatial domain what conventional spectroscopy methods do in the frequency domain employing many frequencies (hyperspectral imaging).

Research paper thumbnail of Identification of Model Particle Mixtures Using Machine-Learning-Assisted Laser Diffraction

Photonics, 2022

We put forward and demonstrate with model particles a smart laser-diffraction analysis technique ... more We put forward and demonstrate with model particles a smart laser-diffraction analysis technique aimed at particle mixture identification. We retrieve information about the size, shape, and ratio concentration of two-component heterogeneous model particle mixtures with an accuracy above 92%. We verify the method by detecting arrays of randomly located model particles with different shapes generated with a Digital Micromirror Device (DMD). In contrast to commonly-used laser diffraction schemes—In which a large number of detectors are needed—Our machine-learning-assisted protocol makes use of a single far-field diffraction pattern contained within a small angle (∼0.26°) around the light propagation axis. Therefore, it does not need to analyze particles of the array individually to obtain relevant information about the ensemble, it retrieves all information from the diffraction pattern generated by the whole array of particles, which simplifies considerably its implementation in compar...

Research paper thumbnail of Characterization of the startup transient electrokinetic flow in rectangular channels of arbitrary dimensions, zeta potential distribution, and time-varying pressure gradient

Electrophoresis, Jan 11, 2014

The solution to the startup transient electroosmotic flow in an arbitrary rectangular micro-chann... more The solution to the startup transient electroosmotic flow in an arbitrary rectangular micro-channel is derived analytically and validated experimentally. This full two dimensional transient solution describes the evolution of the flow through five distinct periods until reaching a final steady state. The derived analytical velocity solution is validated experimentally for different channel sizes and aspect ratios under time-varying pressure gradients. The experiments used a Time Resolved Micro Particle Image Velocimetry technique, TR-μPIV, to calculate the startup transient velocity profiles. The measurements captured the effect of time-varying pressure gradient fields derived in the analytical solutions. This is tested by using small reservoirs at both ends of the channel which allowed a time-varying pressure gradient to develop with a time scale on the order of the transient electroosmotic flow. Results showed that under these common conditions, the effect of the pressure build up...

Research paper thumbnail of Esplenectomia en el tratamiento del linfoma primario de bazo

Rev Invest Clin, Jun 1, 1986

Research paper thumbnail of Instantaneous Aerodynamic Load Calculations in Rotating Airfoils From Time Resolved PIV Measurements at Low Reynolds Number

Volume 7B: Fluids Engineering Systems and Technologies, 2013

ABSTRACT The time-resolved evolution of the instantaneous pressure fields and aerodynamic loads a... more ABSTRACT The time-resolved evolution of the instantaneous pressure fields and aerodynamic loads are obtained for rotating airfoils. This method allows evaluating the fluctuations in the instantaneous aerodynamic loads which cannot be evaluated with averaging methods. It also has the ability of capturing high temporal variations such as vortex shedding in the wake of the rotating blade. Briefly, this method obtains the velocity field from time-resolved particle image velocimetry TR-PIV. This is used to calculate the pressure field around the turbine from the Poisson pressure equation. Then, the forces are obtained using the integral momentum equation in a stationary reference frame. These experimental aerodynamic loads are compared to theoretical predictions from the Blade Element Momentum theory (BEM). Accurately determining instantaneous forces in turbines is needed for safety and understanding of their full range of operation. The standard deviation of the instantaneous forces establishes the limits of the forces expected on the turbine. The uncertainty in the measurements is calculated. The method presented may be used to measure unsteady forces in rotating airfoils, providing useful information not just for computational studies, but also for aerodynamics, material and structural optimization and safety purposes.

Research paper thumbnail of Spatial spectroscopy for high resolution imaging

EPJ Web of Conferences

Quantum estimation theory provides bounds for the precision in the estimation of a set of paramet... more Quantum estimation theory provides bounds for the precision in the estimation of a set of parameters that characterize a system. Two questions naturally arise: Is any of these bounds tight? And if this is the case, what type of measurements can attain such a limit? In this work we show that for phase objects, it is possible to find a tight resolution bound. Moreover one can find a set of spatial modes whose detection provides an optimal estimation of the complete set of parameters for which we propose a homodyne detection scheme. We call this method spatial spectroscopy since it mimics in the spatial domain what conventional spectroscopy methods do in the frequency domain employing many frequencies (hyperspectral imaging).

Research paper thumbnail of Spatial spectroscopy for high resolution imaging

EPJ Web of Conferences

Quantum estimation theory provides bounds for the precision in the estimation of a set of paramet... more Quantum estimation theory provides bounds for the precision in the estimation of a set of parameters that characterize a system. Two questions naturally arise: Is any of these bounds tight? And if this is the case, what type of measurements can attain such a limit? In this work we show that for phase objects, it is possible to find a tight resolution bound. Moreover one can find a set of spatial modes whose detection provides an optimal estimation of the complete set of parameters for which we propose a homodyne detection scheme. We call this method spatial spectroscopy since it mimics in the spatial domain what conventional spectroscopy methods do in the frequency domain employing many frequencies (hyperspectral imaging).