Name: gain-compensation methodology for a sinusoidal scan of a galvanometer mirror in proportional-integral-differential control using pre-emphasis techniques
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Description: Watch this Scientific Journal Video about Gain-compensation Methodology for a Sinusoidal Scan of a Galvanometer Mirror in Proportional-Integral-Differential Control Using Pre-emphasis Techniques at Jo

The authors have no acknowledgements.

1. Acquisition of Gain Data for a Galvanometer Mirror
<ol>
	<li>Fix the galvanometer mirror such that it is stabilized to protect it from damage while oscillating. Not only the galvanometer mirror, but also the body of the galvanometer mirror, moves if not fixed in place using a custom-made metal jig with a circular hole for the galvanometer mirror. Fix the jig onto an optical carrier and an optical bench.</li>
	<li>Connect BNC cables from the AD/DA board through a terminal block to the input and position sockets in th...

<ol>
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P., Group, O., Vlaicu, A., Ave, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Advancements+on+galvanometer+scanners+for+high-end+applications.">Advancements on galvanometer scanners for high-end applications.</a> Proc SPIE. 8936, 1-12 (2014).</li><li>Duma, V. -. F., Lee, K., Meemon, P., Rolland, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Experimental+investigations+of+the+scanning+functions+of+galvanometer-based+scanners+with+applications+in+OCT.">Experimental investigations of the scanning functions of galvanometer-based scanners with applications in OCT.</a> Appl Opt. 50 (29), 5735-5749 (2011).</li><li>Wang, C., Shumyatsky, P., Zeng, F., Zevallos, M., Alfano, R. 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J., Li, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+scanning+all-reflective+optical+delay+line+for+real-time+optical+coherence+tomography.">Rapid scanning all-reflective optical delay line for real-time optical coherence tomography.</a> Opt lett. 29 (1), 80-82 (2004).</li><li>Li, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Laser+beam+scanning+by+rotary+mirrors.+II.+Conic-section+scan+patterns.">Laser beam scanning by rotary mirrors. II. Conic-section scan patterns.</a> Appl opt. 34 (28), 6417-6430 (1995).</li><li>Duma, V. I. L., Tankam, P. A., Huang, J. I., Won, J. U., Rolland, J. A. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optimization+of+galvanometer+scanning+for+optical+coherence+tomography.">Optimization of galvanometer scanning for optical coherence tomography.</a> Appl opt. 54 (17), 5495-5507 (2015).</li><li>Hayakawa, T., Watanabe, T., Ishikawa, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Real-time+high-speed+motion+blur+compensation+system+based+on+back-and-forth+motion+control+of+galvanometer+mirror.">Real-time high-speed motion blur compensation system based on back-and-forth motion control of galvanometer mirror.</a> Opt Exp. 23 (25), 31648-31661 (2015).</li><li>Hayakawa, T., Watanabe, T., Senoo, T., Masatoshi, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gain-compensated+sinusoidal+scanning+of+a+galvanometer+mirror+in+proportional-integral-+differential+control+using+the+pre-emphasis+technique+for+motion-blur+compensation.">Gain-compensated sinusoidal scanning of a galvanometer mirror in proportional-integral- differential control using the pre-emphasis technique for motion-blur compensation.</a> Appl opt. 55 (21), 5640-5646 (2016).</li><li>Visioli, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Practical PID Control. , (2006).</li><li>Vilanova, R., Visioli, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> PID Control in the Third Millennium. , (2012).</li><li>Ortega, R., Kelly, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=PID+Self-Tuners:+Some+Theoretical+and+Practical+Aspects.">PID Self-Tuners: Some Theoretical and Practical Aspects.</a> IEEE Transa Ind Electron. 31 (4), 332-338 (1984).</li><li>Mnerie, C., Preitl, S., Duma, V. -. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mathematical+model+of+a+galvanometer-based+scanner:+simulations+and+experiments.">Mathematical model of a galvanometer-based scanner: simulations and experiments.</a> Proc SPIE. 8789, 878915 (2013).</li><li>Mnerie, C. A., Preitl, S., Duma, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Performance+Enhancement+of+Galvanometer+Scanners+Using+Extended+Control+Structures.">Performance Enhancement of Galvanometer Scanners Using Extended Control Structures.</a> 8th IEEE International Symposium on Applied Computational Intelligence and Informatics. , 127-130 (2014).</li><li>Mnerie, C., Preitl, S., Duma, V. -. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Control+architectures+of+galvanometer-based+scanners+for+an+increased+precision+and+a+faster+response.">Control architectures of galvanometer-based scanners for an increased precision and a faster response.</a> Proc of SPIE. 8925, 892500 (2014).</li><li>Farjad-rad, R., Member, S., Yang, C. K., Horowitz, M. A., Lee, T. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+0.4-+m+CMOS+10-Gb/s+4-PAM+Pre-Emphasis+Serial+Link+Transmitter.">A 0.4- m CMOS 10-Gb/s 4-PAM Pre-Emphasis Serial Link Transmitter.</a> IEEE J Solid-State Circuits. 34 (5), 580-585 (1999).</li><li>Buckwalter, J. F., Meghelli, M., Friedman, D. J., Hajimiri, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phase+and+amplitude+pre-emphasis+techniques+for+low-power+serial+links.">Phase and amplitude pre-emphasis techniques for low-power serial links.</a> IEEE Journal of Solid-State Circuits. 41 (6), 1391-1398 (2006).</li><li>Le, S., Blow, K., Turitsyn, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Power+pre-emphasis+for+suppression+of+FWM+in+coherent+optical+OFDM+transmission.">Power pre-emphasis for suppression of FWM in coherent optical OFDM transmission.</a> Opt exp. 22 (6), 7238-7248 (2014).</li></ol>

This article presents a procedure capable of expanding the sine-wave frequency range to achieve high-accuracy trajectory tracking with PID control. Because the responsiveness of a galvanometer mirror is limited by its inertia, it is critical to use a galvanometer mirror when the control path is steep. However, in this research, we propose a method to improve the specification of control and then prove the method by obtaining experimental results.
In our procedure, step 2.5 is the most critical...

Various optical actuators and control methods suitable for various optical applications have been proposed and developed1,2. These optical actuators are able to control the optical path; galvanometer mirrors especially offer a good balance in terms of accuracy, speed, mobility, and cost3,4,5. Actually, the advantage offered by the speed and accuracy of galvanometer mirrors has led to the realization of a variety of optical applications, such as target tracking and drawing, scanning control, and motion-blur compensation6,7,8,9,10,11,12. However, in our previous motion-blur compensation system, a galvanometer mirror using a proportional-integral-differential (PID) controller provided a small gain; hence, it was difficult to achieve a higher frequency and a faster speed11.
On the other hand, PID control is a widely-used method, as it satisfies a certain level of tracking accuracy13. A variety of methods have been proposed to correct the gain in PID control. As a typical solution, PID control parameter tuning is conducted manually. However, it takes time and special skill to maintain. A more sophisticated method, an auto-tuning function to automatically determine the parameters, has been proposed and is widely used14. The tracking accuracy for high-speed operations is improved using the auto-tuning function when the proportional gain value P increases. However, this also increases the convergence time and noise in the low-speed range. Hence, the tracking accuracy is not necessarily improved. Although a self-tuning controller can be tuned to set suitable parameters for PID control, the tuning introduces a delay because of the need to obtain suitable parameters; therefore, it is difficult to adopt this method in real-time applications15. An extended PID controller16,17 and an extended predictive controller18 have been proposed to extend general PID control and to enhance the tracking performance of galvanometer mirrors for a variety of tracking paths, such as triangular waves, sawtooth waves, and sine waves. However, in those systems, the galvanometer system was regarded as a black box, whereas a model of the control system was required, and the control system was not regarded as a black box. Hence, those methods require that their model for each galvanometer mirror be updated. Moreover, although Mnerie et al. validated their method of focusing on a detailed output wave and phase, their research did not include the attenuation of the entire wave. In fact, in our previous research11, the gain was significantly decreased when the sinusoidal frequency was high, thereby indicating the necessity to compensate for the gain of the entire wave.
In this research, our procedure for gain compensation with PID control12 is based on the pre-emphasis technique19,20,21&#8212;a method to enhance the quality or speed of communication in communications engineering&#8212;which enables the construction of an experimental system using existing equipment. Figure 1 shows the flow structure. The pre-emphasis technique is able to obtain in advance the desired output value from an input value, where PID control is not effective, even if the galvanometer mirror and its controller are regarded as black boxes. This enables them to expand the frequency and amplitude range in which a gain of 0 dB can be obtained without tuning the PID control parameters.
When the gain is amplified, the response characteristics of the galvanometer mirror generally differ at different frequencies, and therefore, we need to amplify each frequency with amplification coefficients. Thus, a sine wave is suitable for the pre-emphasis technique, as there is only one frequency in each sine wave. In this research, because we apply gain compensation to accomplish motion-blur compensation, the control signal is limited to sine-wave scanning, and the sine-wave signal constitutes a single frequency, unlike other waves, such as triangular and sawtooth waves. Further, the input signal into the galvanometer mirror is updated immediately within the next cycle because of the open loop after the pre-emphasis coefficients are set. In other words, we need to know only the input-to-output ratio to regard the controller as a black box, and detailed modeling is not required. This simplicity allows our system to be easily embedded in applications.
The overall goal of this method is to establish an experimental procedure of motion-blur compensation as an application by gain compensation using the pre-emphasis technique. Multiple hardware devices are used in these procedures, such as a galvanometer mirror, a camera, a conveyor belt, illumination, and a lens. Central software user-developed programs written in C++ also constitute part of the system. Figure 2 shows a schematic of the experimental setup. The galvanometer mirror rotates with gain-compensated angular velocity, thereby making it possible to evaluate the amount of blur from the images.

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		<col />
		<col />
		<col />
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	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Galvanometer mirror</td>
			<td style="width:71px;">GSI</td>
			<td style="width:119px;">M3s X axis</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Custom-made metal jig</td>
			<td style="width:71px;">ASKK</td>
			<td style="width:119px;">-</td>
			<td>With circular hole for galvanometer mirror</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Optical carrier</td>
			<td style="width:71px;">SIGMAKOKI</td>
			<td style="width:119px;">CAA-60L</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Optical bench</td>
			<td style="width:71px;">SIGMAKOKI</td>
			<td style="width:119px;">OBT-1500LH</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Oscilloscope</td>
			<td style="width:71px;">Tektronix</td>
			<td style="width:119px;">MSO 4054</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">AD/DA board</td>
			<td style="width:71px;">Interface</td>
			<td style="width:119px;">PCI-361216</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">PC</td>
			<td style="width:71px;">DELL</td>
			<td style="width:119px;">Precision T3600</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Galvanometer mirror servo controller</td>
			<td style="width:71px;">GSI</td>
			<td style="width:119px;">Minisax</td>
			<td></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">Lens</td>
			<td style="width:71px;">Nikkor</td>
			<td style="width:119px;">AF-S NIKKOR 200mm f/2G ED VR II&#160;</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">High-speed camera</td>
			<td style="width:71px;">Mikrotron</td>
			<td style="width:119px;">Eosens MC4083</td>
			<td>Discontinued, but sold as MC4087. The cable connection is different from MC4083</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Conveyor belt</td>
			<td style="width:71px;">ASUKA</td>
			<td style="width:119px;">-</td>
			<td>With a speed-control motor(BX5120A-A made by Oriental Motor), iron rubber belt(100-F20-800A-J made by NOK), and so on</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Printable tape</td>
			<td style="width:71px;">A-one</td>
			<td style="width:119px;">F20A4-6</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Photographic texture</td>
			<td style="width:71px;">Shutterstock, Inc.</td>
			<td align="right" style="width:119px;">231357754</td>
			<td>Printed computer motherboard with microcircuit, close up</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Terminal block</td>
			<td style="width:71px;">Interface</td>
			<td style="width:119px;">TNS-6851B</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">CoaXPress board</td>
			<td style="width:71px;">AVALDATA</td>
			<td style="width:119px;">APX-3664</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">MATLAB</td>
			<td style="width:71px;">mathworks</td>
			<td style="width:119px;">MATLAB R2015a</td>
			<td></td>
		</tr>
	</tbody>
</table>

gain-compensation methodology for a sinusoidal scan of a galvanometer mirror in proportional-integral-differential control using pre-emphasis techniques

Galvanometer mirrors are used for optical applications such as target tracking, drawing, and scanning control because of their high speed and accuracy. However, the responsiveness of a galvanometer mirror is limited by its inertia; hence, the gain of a galvanometer mirror is reduced when the control path is steep. In this research, we propose a method to extend the corresponding frequency using a pre-emphasis technique to compensate for the gain reduction of galvanometer mirrors in sine-wave path tracking using proportional-integral-differential (PID) control. The pre-emphasis technique obtains an input value for a desired output value in advance. Applying this method to control the galvanometer mirror, the raw gain of a galvanometer mirror in each frequency and amplitude for sine-wave path tracking using a PID controller was calculated. Where PID control is not effective, maintaining a gain of 0 dB to improve the trajectory tracking accuracy, it is possible to expand the speed range in which a gain of 0 dB can be obtained without tuning the PID control parameters. However, if there is only one frequency, amplification is possible with a single pre-emphasis coefficient. Therefore, a sine wave is suitable for this technique, unlike triangular and sawtooth waves. Hence, we can adopt a pre-emphasis technique to configure the parameters in advance, and we need not prepare additional active control models and hardware. The parameters are updated immediately within the next cycle because of the open loop after the pre-emphasis coefficients are set. In other words, to regard the controller as a black box, we need to know only the input-to-output ratio, and detailed modeling is not required. This simplicity allows our system to be easily embedded in applications. Our method using the pre-emphasis technique for a motion-blur compensation system and the experiment conducted to evaluate the method are explained.

The results presented here were obtained using an AD/DA board and a camera. Figure 1 shows the procedure of the pre-emphasis technique; therefore, it is the core of this article. It is unnecessary to set the parameters of the PID control after the initialization state; hence, the online process is significantly simple.
Figure 10 shows the results obtained by applying the pre-emphasis technique t...

Watch this Scientific Journal Video about Gain-compensation Methodology for a Sinusoidal Scan of a Galvanometer Mirror in Proportional-Integral-Differential Control Using Pre-emphasis Techniques at Jo

Gain-compensation Methodology for a Sinusoidal Scan of a Galvanometer Mirror in Proportional-Integral-Differential Control Using Pre-emphasis Techniques

We propose a method to extend the corresponding frequency by using a pre-emphasis technique. This method compensates for the gain reduction of a galvanometer mirror in sine-wave path tracking using proportional-integral-differential control.

Galvanometer mirrors are used for optical applications such as target tracking, drawing, and scanning control because of their high speed and accuracy. ...

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Liquid crystalline elastomers (LCEs) are smart materials capable of reversible shape-change in response to external stimuli, and have attracted researchers&#39; attention in many fields. Most of the studies focused on macroscopic LCE structures (films, fibers) and their miniaturization is still in its infancy. Recently developed lithography techniques, e.g., mask exposure and replica molding, only allow for creating 2D structures on LCE thin films. Direct laser writing (DLW) opens access to truly 3D fabrication in the microscopic scale. However, controlling the actuation topology and dynamics at the same length scale remains a challenge.
In this paper we report on a method to control the liquid crystal (LC) molecular alignment in the LCE microstructures of arbitrary three-dimensional shape. This was made possible by a combination of direct laser writing for both the LCE structures as well as for micrograting patterns inducing local LC alignment. Several types of grating patterns were used to introduce different LC alignments, which can be subsequently patterned into the LCE structures. This protocol allows one to obtain LCE microstructures with engineered alignments able to perform multiple opto-mechanical actuation, thus being capable of multiple functionalities. Applications can be foreseen in the fields of tunable photonics, micro-robotics, lab-on-chip technology and others.

Free-form Light Actuators &amp;#8212; Fabrication and Control of Actuation in Microscopic Scale

Here, we fabricate 3D polymeric micro/nano structures in which both the shape and the molecular alignment can be engineered with nanometer scale accuracy by the use of direct laser writing. Light induced deformation of several types of liquid crystalline elastomer microstructures can be controlled in the microscopic scale.

Liquid crystalline elastomers (LCEs) are smart materials capable of reversible shape-change in response to external stimuli, and have attracted ...

Study of Siphon Breaker Experiment and Simulation for a Research Reactor

Under the design conditions of a research reactor, the siphon phenomenon induced by pipe rupture can cause continuous outward flow of water. To prevent this outflow, a control device is required. A siphon breaker is a type of safety device that can be utilized to control the loss of coolant water effectively.
To analyze the characteristics of siphon breaking, a real-scale experiment was conducted. From the results of the experiment, it was found that there are several design factors that affect the siphon breaking phenomenon. Therefore, there is a need to develop a theoretical model capable of predicting and analyzing the siphon breaking phenomenon under various design conditions. Using the experimental data, it was possible to formulate a theoretical model that accurately predicts the progress and the result of the siphon breaking phenomenon. The established theoretical model is based on fluid mechanics and incorporates the Chisholm model to analyze two-phase flow. From Bernoulli&#39;s equation, the velocity, quantity, undershooting height, water level, pressure, friction coefficient, and factors related to the two-phase flow could be obtained or calculated. Moreover, to utilize the model established in this study, a siphon breaker analysis and design program was developed. The simulation program operates on the theoretical model basis and returns the result as a graph. The user can confirm the possibility of the siphon breaking by checking the shape of the graph. Furthermore, saving the entire simulation result is possible and it can be used as a resource for analyzing the real siphon breaking system.
In conclusion, the user can confirm the status of the siphon breaking and design the siphon breaker system using the program developed in this study.

The siphon breaking phenomenon was investigated experimentally and a theoretical model was proposed. A simulation program based on the theoretical model was developed and the results of the simulation program were compared with experimental results. It was concluded that the results of the simulation program matched the experimental results well.

Under the design conditions of a research reactor, the siphon phenomenon induced by pipe rupture can cause continuous outward flow of water. To prevent ...

Electric-field Control of Electronic States in WS2 Nanodevices by Electrolyte Gating

A method of carrier number control by electrolyte gating is demonstrated. We have obtained WS2 thin flakes with atomically flat surface via scotch tape method or individual WS2 nanotubes by dispersing the suspension of WS2 nanotubes. The selected samples have been fabricated into devices by the use of the electron beam lithography and electrolyte is put on the devices. We have characterized the electronic properties of the devices under applying the gate voltage. In the small gate voltage region, ions in the electrolyte are accumulated on the surface of the samples which leads to the large electric potential drop and resultant electrostatic carrier doping at the interface. Ambipolar transfer curve has been observed in this electrostatic doping region. When the gate voltage is further increased, we met another drastic increase of source-drain current which implies that ions are intercalated into layers of WS2 and electrochemical carrier doping is realized. In such electrochemical doping region, superconductivity has been observed. The focused technique provides a powerful strategy for achieving the electric-filed-induced quantum phase transition.

Electric-field Control of Electronic States in WS2 Nanodevices by Electrolyte Gating

Here, we present a protocol to control the carrier number in solids by using the electrolyte.

A method of carrier number control by electrolyte gating is demonstrated. We have obtained WS2 thin flakes with atomically flat surface via scotch tape ...

Simultaneous Measurement of Turbulence and Particle Kinematics Using Flow Imaging Techniques

Numerous problems in scientific and engineering fields involve understanding the kinematics of particles in turbulent flows, such as contaminants, marine micro-organisms, and/or sediments in the ocean, or fluidized bed reactors and combustion processes in engineered systems. In order to study the effect of turbulence on the kinematics of particles in such flows, simultaneous measurements of both the flow and particle kinematics are required. Non-intrusive, optical flow measurement techniques for measuring turbulence, or for tracking particles, exist but measuring both simultaneously can be challenging due to interference between the techniques. The method presented herein provides a low cost and relatively simple method to make simultaneous measurements of the flow and particle kinematics. A cross section of the flow is measured using a particle image velocimetry (PIV) technique, which provides two components of velocity in the measurement plane. This technique utilizes a pulsed-laser for illumination of the seeded flow field that is imaged by a digital camera. The particle kinematics are simultaneously imaged using a light emitting diode (LED) line light that illuminates a planar cross section of the flow that overlaps with the PIV field-of-view (FOV). The line light is of low enough power that it does not affect the PIV measurements, but powerful enough to illuminate the larger particles of interest imaged using the high-speed camera. High-speed images that contain the laser pulses from the PIV technique are easily filtered by examining the summed intensity level of each high-speed image. By making the frame rate of the high-speed camera incommensurate with that of the PIV camera frame rate, the number of contaminated frames in the high-speed time series can be minimized. The technique is suitable for mean flows that are predominantly two-dimensional, contain particles that are at least 5 times the mean diameter of the PIV seeding tracers, and are low in concentration.

The technique described herein offers a low cost and relatively simple method to simultaneously measure particle kinematics and turbulence in flows with low particle concentrations. The turbulence is measured using particle image velocimetry (PIV), and particle kinematics are calculated from images obtained with a high-speed camera in an overlapping field-of-view.

Numerous problems in scientific and engineering fields involve understanding the kinematics of particles in turbulent flows, such as contaminants, marine ...

Microfluidic Fabrication Techniques for High-Pressure Testing of Microscale Supercritical CO2 Foam Transport in Fractured Unconventional Reservoirs

Pressure limitations of many microfluidic platforms have been a significant challenge in microfluidic experimental studies of fractured media. As a result, these platforms have not been fully exploited for direct observation of high-pressure transport in fractures. This work introduces microfluidic platforms that enable direct observation of multiphase flow in devices featuring surrogate permeable media and fractured systems. Such platforms provide a pathway to address important and timely questions such as those related to CO2 capture, utilization and storage. This work provides a detailed description of the fabrication techniques and an experimental setup that may serve to analyze the behavior of supercritical CO2 (scCO2) foam, its structure and stability. Such studies provide important insights regarding enhanced oil recovery processes and the role of hydraulic fractures in resource recovery from unconventional reservoirs. This work presents a comparative study of microfluidic devices developed using two different techniques: photolithography/wet-etching/thermal-bonding versus Selective Laser-induced Etching. Both techniques result in devices that are chemically and physically resistant and tolerant of high pressure and temperature conditions that correspond to subsurface systems of interest. Both techniques provide pathways to high-precision etched microchannels and capable lab-on-chip devices. Photolithography/wet-etching, however, enables fabrication of complex channel networks with complex geometries, which would be a challenging task for laser etching techniques. This work summarizes a step-by-step photolithography, wet-etching and glass thermal-bonding protocol and, presents representative observations of foam transport with relevance to oil recovery from unconventional tight and shale formations. Finally, this work describes the use of a high-resolution monochromatic sensor to observe scCO2 foam behavior where the entirety of the permeable medium is observed simultaneously while preserving the resolution needed to resolve features as small as 10 &#181;m.

Microfluidic Fabrication Techniques for High-Pressure Testing of Microscale Supercritical CO2 Foam Transport in Fractured Unconventional Reservoirs

This paper describes a protocol along with a comparative study of two microfluidic fabrication techniques, namely photolithography/wet-etching/thermal-bonding and Selective Laser-induced Etching (SLE), that are suitable for high-pressure conditions. These techniques constitute enabling platforms for direct observation of fluid flow in surrogate permeable media and fractured systems under reservoir conditions.

Pressure limitations of many microfluidic platforms have been a significant challenge in microfluidic experimental studies of fractured media. As a ...

Manufacturing, Control, and Performance Evaluation of a Gecko-Inspired Soft Robot

This protocol presents a method for manufacturing, control, and evaluation of the performance of a soft robot that can climb inclined flat surfaces with slopes of up to 84&#176;. The manufacturing method is valid for the fast pneunet bending actuators in general and might, therefore, be interesting for newcomers to the field of actuator manufacturing. The control of the robot is achieved by means of a pneumatic control box that can provide arbitrary pressures and can be built by only using purchased components, a laser cutter, and a soldering iron. For the walking performance of the robot, the pressure-angle calibration plays a crucial role. Therefore, a semi-automated method for the pressure-angle calibration is presented. At high inclines (&#62; 70&#176;), the robot can no longer reliably fix itself to the walking plane. Therefore, the gait pattern is modified to ensure that the feet can be fixed on the walking plane.

This protocol provides a detailed list of steps to be performed for the manufacturing, control and evaluation of the climbing performance of a gecko-inspired soft robot.

This protocol presents a method for manufacturing, control, and evaluation of the performance of a soft robot that can climb inclined flat surfaces with ...

Computer Numerical Control Micromilling of a Microfluidic Acrylic Device with a Staggered Restriction for Magnetic Nanoparticle-Based Immunoassays

Microfluidic systems have greatly improved immunoassay techniques. However, many microfabrication techniques require specialized, expensive, or complicated equipment, making fabrication costly and incompatible with mass production, which is one of the most important preconditions for point-of-care tests (POCT) to be adopted in low-resource settings. This work describes the fabrication process of an acrylic (polymethylmethacrylate, PMMA) device for nanoparticle-conjugated enzymatic immunoassay testing using the computer numerical control (CNC) micromilling technique. The functioning of the microfluidic device is shown by performing an immunoassay to detect a commercial antibody using lysozyme as a model antigen conjugated to 100 nm magnetic nanoparticles. This device integrates a physical staggered restriction of only 5 &#181;m in height, used to capture magnetic microparticles that make up a magnetic trap by placing an external magnet. In this way, the magnetic force on the immunosupport of conjugated nanoparticles is enough to capture them and resist flow drag. This microfluidic device is particularly suitable for low-cost mass production without the loss of precision for immunoassay performance.

Microfluidics is a powerful tool for the development of diagnostic tests. However, expensive equipment and materials, as well as laborious fabrication and handling techniques, are often required. Here, we detail the fabrication protocol of an acrylic microfluidic device for magnetic micro- and nanoparticle-based immunoassays in a low-cost and simple-to-use setting.