This work was supported in part by the National Natural Science Foundation of China under Grant 62103308 and Grant 62073247, in part by the Fundamental Research Funds for the Central Universities under Grant 2042023kf0095, in part by the China Postdoctoral Science Foundation under Grant 2022T150496, and in part by Wuhan University Experiment Technology Project Funding under Grant WHU-2022-SYJS-10.

This study met the guidelines of the Human Research Ethics Committee at Wuhan University, and informed consent was obtained for all experimental data. In this paper, the experimental steps for the double-inverted pendulum system are discussed, and all the steps are performed in the WebVR-based NCSLab.
1. Access WebVR-based NCSLab system
<ol>
	<li>Open a web browser that supports WebVR. Enter the Uniform Resource Locator (URL) of the WebVR-based NCSLab to access the system.</li>
	<li>Click the Start Experiment button to log into the NCSLab system. If it is the first-time logging into the system, do an account registration.</li>
	<li>Log into the NCSLab system, select different experiments from the left menu bar, and choose the double inverted pendulum experiment in this case.</li>
	<li>Access the 3D sub-page on the main page. 
	NOTE: There are five sub-pages on the main page, beginning with the first one, which is the introduction of the equipment model. It contains a 3D model animation as well as documentation. By visiting this page, users can grasp the principle of the double inverted pendulum system, enabling convenient execution of subsequent experiments.</li>
	<li>Apply for experiment control by clicking the Request Control button to ensure efficient use of resources. This will grant users 30 min of experiment time. 
	NOTE: For virtual experiments, 500 users can be allowed to conduct experiments at the same time.</li>
	<li>Enter the plant information sub-page to gain access to comprehensive details regarding the experimental apparatus. This encompasses information on equipment that is currently in use, equipment that remains unused, and maintenance-related equipment.</li>
	<li>Choose the system default control algorithm to download on the Experimental Algorithm sub-page. Alternatively, proceed to the Algorithm Design sub-page to design a different algorithm.
	<ol>
		<li>To design a new control algorithm, click the Create New Model button on the algorithm design sub-page to enter the design interface. 
		NOTE: The process of algorithm design closely mirrors that of MATLAB/Simulink, whereby users construct the control algorithm block diagram through an intuitive drag-and-drop approach, employing various modules to craft the desired control logic.</li>
		<li>Build the complete control algorithm block diagram, as depicted in Figure 1, and follow the steps described below.</li>
		<li>Select the Double Inverted Pendulum System Module from the device model on the left.</li>
		<li>Choose the Gain Module to design the feedback matrix for the Linear Quadratic Regulator (LQR) controller.</li>
		<li>Select the Step Signal as input and add other modules. Double-click the module to view detailed information and modify the parameter configuration. For example, double-click the Constant Signal Module to modify the value of the constant signal.</li>
	</ol>
	</li>
	<li>Click the Start Simulation button upon completing the control algorithm design. Upon completion of the simulation, observe the control effectiveness of the designed algorithm. If unsatisfied with the simulation results, fine-tune the parameters of the LQR controllers until a control algorithm with improved performance is achieved.</li>
	<li>Click the Compile button to generate the control algorithm. After compilation, the algorithm is stored in the private algorithm area of the experimental algorithm sub-page and the algorithm design sub-page.</li>
	<li>Download the control algorithm on the experimental algorithm sub-page by clicking the Download Algorithm button located on the right side of the control algorithm section.</li>
	<li>Select an experimental configuration and conduct experiments on the Monitoring Configuration sub-page. The system provides a pre-defined configuration to meet the general experimental requirements of users. 
	NOTE: Users have the flexibility to click the Create New monitor button to craft a customized monitoring setup tailored to their specific experimental demands.</li>
	<li>Customize the monitoring configuration and choose from a variety of components available in the editing interface of the monitoring configuration sub-page, as depicted in Figure 2. These components include input variable components, output variable curve display components, and 3D model components.</li>
	<li>For VR experiments, select the 3D model component. The 3D model component allows users to integrate a 3D model into the monitoring configuration.</li>
	<li>To facilitate parameter configuration, adjust the parameters for each component, which are directly linked to system parameter variables. Double-click on a component and access the window to select the relevant optional parameters within the experimental system.</li>
	<li>Users have the flexibility to optimize the layout of the monitoring configuration by resizing components. To do this, drag the edges of the respective components to the desired dimensions.</li>
	<li>Click the Save button to save the designed monitoring configuration for future use in subsequent experiments, saving time and effort for setting up the monitoring system repeatedly. 
	NOTE: The monitoring configuration can only be performed after the control algorithm has been correctly downloaded.</li>
	<li>Click the Start Experiment button on the window to initiate the experiment. Click the VR Button in the bottom right corner of the 3D model component to launch the VR experiment. 
	NOTE: The VR experiment is embedded on the web page. When users use it for the first time, the browser may prompt them in the top left corner to allow the browser to use VR functionality, select Allow to proceed.</li>
</ol>
2. Selecting the access method
<ol>
	<li>Use a WebVR emulator extension. To engage in experimentation using this method, install the WebVR emulator extension, which is readily available for search and download from the browser&#39;s extension store. 
	NOTE: The WebVR emulator extension helps users run WebVR content in a web browser and provides the virtual VR headset and the handles controller environment without the need to use the real VR device.</li>
	<li>Use VR devices that support WebVR. If VR devices are used for the first time, the basic environment configuration is needed. First, turn ON the power of the headset and controller to start the system. Set up the initial ROOM program in the headset. Following the visual cues displayed on the headset screen, use the handle controllers to carefully calibrate the boundaries and orientation of the virtual space environment. Finally, establish a streaming connection between the headset and the computer. 
	NOTE: This is the second method to access the proposed system. VR devices generally include a headset and a pair of handle controllers. VR devices have built-in stores where users can download WebVR-enabled browsers. Alternatively, users can use the built-in browser, which generally supports WebVR. It is noteworthy that various VR devices may employ distinct methods for connectivity.</li>
</ol>
3. Experimental procedure
<ol>
	<li>Adjust the perspective to find the optimal position for conducting the double inverted pendulum system experiment.
	<ol>
		<li>For users utilizing the WebVR emulator extension, open the Developer Tools, locate the WebVR extension, and manipulate the virtual VR device using the mouse to adjust the perspective, as shown in Figure 3.</li>
		<li>For users employing VR devices, immerse in the virtual experimental environment and ascertain the optimal experimental position through physical movements.</li>
	</ol>
	</li>
	<li>Interact with the double inverted pendulum system using the handle controller as described below.
	<ol>
		<li>Move the handle closer to the cube. Press the Trigger button to pick up the cube and the double-inverted pendulum system will stop moving.</li>
		<li>By moving the handle, control the position of the cube. Release the cube once it is in the desired position by releasing the trigger button. The position is now designated as the subsequent setpoint for the cart, as depicted in Figure 3.</li>
	</ol>
	</li>
	<li>Observe the motion process of the double inverted pendulum system. By manipulating the Alternating Current (AC) servo motor, set the belt in motion. Under the impetus of the belt, the inverted pendulum can move along the guide rail, The system structure of the double inverted pendulum is elucidated in Figure 4. Eventually, the double inverted pendulum will stabilize at the setpoint.</li>
	<li>Encourage users to iteratively manipulate the cube&#39;s position, continuously adjust the cart&#39;s setpoint, and meticulously observe the dynamic behavior of the double inverted pendulum system.</li>
</ol>

WebVR-Based Virtual Reality Laboratory System for Immersive Online Experiments

<ol>
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The authors have nothing to disclose.

The presented protocol describes a virtual laboratory system that enables users to conduct VR experiments online but also uses a low-cost PC controller28, which is conducive to large-scale application promotion. Users can gain knowledge about the entire experimental process, from principles and algorithms to practical experimental operations. This system allows users to immerse themselves in the experiments, eliminating the reliance on traditional mouse and keyboard input. This system provides an ...

With the advancement of the Internet and the popularity of mobile devices, the demand for online education is increasing1. In particular, during periods of widespread epidemics, traditional educational institutions often face challenges in conducting in-person instruction effectively, which highlights the importance of online education as an important pedagogical approach2. Theoretical courses are relatively easy to transfer to online platforms. They can be conducted with the help of tools such as remote video conferencing software and massive open online courses (MOOCs)3. However, practical courses face greater challenges as they require users to perform hands-on experiments in traditional laboratories.
Researchers have made significant contributions to addressing the challenge of making experimental equipment available online. Over the past two decades, extensive studies have been conducted on the concepts and technologies of online laboratories4,5. Online laboratories typically encompass remote laboratories6, virtual laboratories7, and hybrid laboratories8. These online laboratory approaches have found widespread application in various engineering disciplines, including control engineering9, mechanical engineering10, and software engineering11.
While significant progress has been made in terms of the convenience of experimental operations in online laboratories12, users still perceive a lack of realism and similar hands-on practical operations compared to traditional laboratory environments, which affects their overall experience13. This discrepancy in user experience motivates further research and development efforts to enhance realism and engagement in online laboratory environments.
To solve the above problems, virtual reality (VR) technology has been applied in virtual laboratories14 to improve the immersiveness and interactivity of virtual laboratories15. VR-based virtual laboratories provide users with a close-to-realistic experimental experience. Users can complete group assignments in the architectural education process through avatars16, performing the architectural surveying process together immersively, just as they would in a traditional classroom environment. Furthermore, the VR-based virtual laboratories allow users to enter the immersive environment of virtual laboratories and interact with virtual experimental equipment by wearing VR headsets and handles17, improving users' hands-on abilities18. For different educational purposes, we can design different virtual environments. For example, VR can be combined with gamification theory to enhance engineering education for the general public and to improve the efficiency of disseminating difficult-to-understand knowledge such as sustainable development19.
Similar to online laboratories, particularly virtual laboratories, WebVR-based virtual laboratories have many advantages. Firstly, they break through the time and space limitations of traditional laboratories, and users can conduct experiments anytime and anywhere20. Secondly, online laboratories can provide a safer experimental environment to avoid possible dangers and accidents in experimental operations21. Thirdly, virtual laboratories can also provide more experimental resources and simulation situations to extend users' experimental scope and experience22. Most importantly, WebVR-based virtual laboratories can stimulate users' learning interest and initiative and enhance their experimental experience and participation23.
Compared with other VR-based virtual laboratories, WebVR-based virtual laboratory seamlessly combines the merits of VR-based virtual laboratories with web-based online laboratories. Virtual Instrument Systems in Reality (VISIR)24 builds a basic analog electronic remote laboratory by constructing real circuit boards. Users can perform simulated experiments on the web interface to complete real circuit board experiments. Weblab-Deusto8 builds the water tank Field Programmable Gate Array (FPGA) laboratory where users can interact with the three-dimensional (3D) model of the water tank in the web platform without relying on other plug-ins. The system proposed in this paper introduces the capability to seamlessly integrate WebVR as a modular component into the existing virtual laboratory infrastructure. This integration can be achieved without destroying the original architectural framework of the laboratory, thus preserving the basic structure and function of the laboratory. This integration is also applicable to the framework of an online laboratory with separate front end and back end.
The system proposed in this paper is implemented based on Networked Control System Laboratory (NCSLab)25, which inherits the flexibility, interactivity, modularity, and cross-platform features of the NCSLab system. Users can conduct experiments according to different modules and can also customize algorithms and configuration interfaces, providing users with enough space for self-realization. Online experiments are driven in real-time according to the algorithms run by the user. Users can interact with the virtual model to change the inputs of the experimental algorithm when conducting VR experiments and can even change the parameters of the control algorithm through the components so that users can experience the principle of the control algorithm more realistically.
WebVR-based virtual laboratories bring great potential for online education. It can provide an immersive experimental experience, overcome the limitations of traditional laboratories, and promote hands-on practical skills and innovative thinking among users.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>3DS Max</td>
			<td>Autodesk</td>
			<td></td>
			<td>3ds Max professional 3D modeling, rendering, and animation software enables you to create expansive worlds and premium designs. 
			https://www.autodesk.com/ca-en/products/3ds-max/overview</td>
		</tr>
		<tr>
			<td>Meta Quest 2</td>
			<td>Meta Platforms</td>
			<td>10036728220341</td>
			<td>meta quest 2 is a standalone virtual reality headset that allows users to experience WebVR content. 
			https://www.meta.com/it/quest/products/quest-2/</td>
		</tr>
		<tr>
			<td>Unity</td>
			<td>Unity Technologies</td>
			<td></td>
			<td>Unity is the platform for real-time 3D interactive content creation and operation. 
			All creators, including game developers, artists, architects, automotive designers, film and television, use Unity to bring their ideas to life. 
			The Unity platform offers a complete suite of software solutions for creating, operating, and realizing any real-time interactive 2D and 3D content 
			on cell phones, tablets, PCs, game consoles, augmented reality, and virtual reality devices. 
			https://unity.com/cn</td>
		</tr>
	</tbody>
</table>

online virtual reality networked control laboratory applied in control engineering education

Online laboratories play an important role in engineering education. This work discusses a WebVR-based virtual laboratory system. The user enters the simulated laboratory environment through a virtual reality (VR) device and interacts with the experimental equipment, similar to hands-on experiments in a physical laboratory. In addition, the proposed system allows users to design their own control algorithms and observe the effects of different control parameters to enhance their understanding of the experiment. To illustrate the features of the proposed virtual laboratory, an example is provided in this paper, which is an experiment on a double inverted pendulum system. The experimental results show that the proposed system allows users to conduct experiments in an immersive and interactive manner and provides users with a complete experimental process from principal design to experimental operation. A solution is also provided to change any virtual laboratory into a WebVR-based virtual laboratory for education and training.

The VR experiment system presented provides users with the capability to engage in immersive experiments using VR devices, thereby enhancing the interaction between users and the experimental equipment. Furthermore, the system is web-based, eliminating the need for users to configure local environments. This design allows for the system&#39;s scalability, making it suitable for large-scale applications and training and educational purposes.
In traditional laboratory environments, users are req...

Read this Scientific Article Protocol about Enhancing Engineering Education via WebVR-Based Online Laboratories at JoVE.com

Author Spotlight: Enhancing Engineering Education via WebVR-Based Online Laboratories

This study describes a WebVR-based online virtual reality (VR) laboratory system that provides users with immersive and interactive experimentation capabilities supported by VR devices. The proposed system not only helps to enhance the realism of user participation in online experiments but is also applicable to a wide range of online laboratory frameworks.

Online Virtual Reality Networked Control Laboratory Applied in Control Engineering Education

Online laboratories play an important role in engineering education. This work discusses a WebVR-based virtual laboratory system. The user enters the ...

online-virtual-reality-networked-control-laboratory-applied-control

Research

Education

JoVE Core

JoVE Journal

Electrical Engineering

Engineering

Unit 1

Design of Control Systems

SCIENTISTS IN ACTION

848 Views.  Wuhan University. This study describes a WebVR-based online virtual reality (VR) laboratory system that provides users with immersive and interactive experimentation capabilities supported by VR devices. The proposed system not only helps to enhance the realism of user participation in online experiments but is also applicable to a wide range of online laboratory frameworks.

Video: Author Spotlight: Enhancing Engineering Education via WebVR-Based Online Laboratories

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

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.

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 ...

Hand Controlled Manipulation of Single Molecules via a Scanning Probe Microscope with a 3D Virtual Reality Interface

Considering organic molecules as the functional building blocks of future nanoscale technology, the question of how to arrange and assemble such building blocks in a bottom-up approach is still open. The scanning probe microscope (SPM) could be a tool of choice; however, SPM-based manipulation was until recently limited to two dimensions (2D). Binding the SPM tip to a molecule at a well-defined position opens an opportunity of controlled manipulation in 3D space. Unfortunately, 3D manipulation is largely incompatible with the typical 2D-paradigm of viewing and generating SPM data on a computer. For intuitive and efficient manipulation we therefore couple a low-temperature non-contact atomic force/scanning tunneling microscope (LT NC-AFM/STM) to a motion capture system and fully immersive virtual reality goggles. This setup permits &#34;hand controlled manipulation&#34; (HCM), in which the SPM tip is moved according to the motion of the experimenter&#39;s hand, while the tip trajectories as well as the response of the SPM junction are visualized in 3D. HCM paves the way to the development of complex manipulation protocols, potentially leading to a better fundamental understanding of nanoscale interactions acting between molecules on surfaces. Here we describe the setup and the steps needed to achieve successful hand-controlled molecular manipulation within the virtual reality environment.

We demonstrate the precise manipulation of individual organic molecules on a metal surface with the tip of a scanning probe microscope driven in 3D by the experimenter's hand using a motion capture system and fully immersive virtual reality goggles.

Considering organic molecules as the functional building blocks of future nanoscale technology, the question of how to arrange and assemble such building ...

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.

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. ...

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 ...

Generation and Coherent Control of Pulsed Quantum Frequency Combs

We present a method for the generation and coherent manipulation of pulsed quantum frequency combs. Until now, methods of preparing high-dimensional states on-chip in a practical way have remained elusive due to the increasing complexity of the quantum circuitry needed to prepare and process such states. Here, we outline how high-dimensional, frequency-bin entangled, two-photon states can be generated at a stable, high generation rate by using a nested-cavity, actively mode-locked excitation of a nonlinear micro-cavity. This technique is used to produce pulsed quantum frequency combs. Moreover, we present how the quantum states can be coherently manipulated using standard telecommunications components such as programmable filters and electro-optic modulators. In particular, we show in detail how to accomplish state characterization measurements such as density matrix reconstruction, coincidence detection, and single photon spectrum determination. The presented methods form an accessible, reconfigurable, and scalable foundation for complex high-dimensional state preparation and manipulation protocols in the frequency domain.

A protocol is presented for the practical generation and coherent manipulation of high-dimensional frequency-bin entangled photon states using integrated micro-cavities and standard telecommunications components, respectively.

We present a method for the generation and coherent manipulation of pulsed quantum frequency combs. Until now, methods of preparing high-dimensional ...

Generation and Control of Electrohydrodynamic Flows in Aqueous Electrolyte Solutions

To drive electrohydrodynamic (EHD) flows in aqueous solutions, the separation of cation and anion transport pathways is essential because a directed electric body force has to be induced by ionic motions in liquid. On the other hand, positive and negative charges attract each other, and electroneutrality is maintained everywhere in equilibrium conditions. Furthermore, an increase in an applied voltage has to be suppressed to avoid water electrolysis, which causes the solutions to become unstable. Usually, EHD flows can be induced in non-aqueous solutions by applying extremely high voltages, such as tens of kV, to inject electrical charges. In this study, two methods are introduced to generate EHD flows induced by electrical charge separations in aqueous solutions, where two liquid phases are separated by an ion-exchange membrane. Due to a difference in the ionic mobility in the membrane, ion concentration polarization is induced between both sides of the membrane. In this study, we demonstrate two methods. (i) The relaxation of ion concentration gradients occurs via a flow channel that penetrates an ion-exchange membrane, where the transport of the slower species in the membrane selectively becomes dominant in the flow channel. This is a driving force to generate an EHD flow in the liquid. (ii) A long waiting time for the diffusion of ions passing through the ion-exchange membrane enables the generation of an ion-dragged flow by externally applying an electric field. Ions concentrated in a flow channel of a 1 x 1 mm2 cross-section determine the direction of the liquid flow, corresponding to the electrophoretic transport pathways. In both methods, the electric voltage difference required for an EHD flow generation is drastically reduced to near 2 V by rectifying the ion transport pathways.

The rectification of ion transport pathways is an effective method to generate one-directional ion-dragged electrohydrodynamic flows. By setting an ion-exchange membrane in a flow channel, an electrically polarized condition is generated and causes a liquid flow to be driven when an electric field is externally applied.

To drive electrohydrodynamic (EHD) flows in aqueous solutions, the separation of cation and anion transport pathways is essential because a directed ...

Radio Frequency Magnetron Sputtering of GdBa2Cu3O7&#8722;&#948;/ La0.67Sr0.33MnO3 Quasi-bilayer Films on SrTiO3 (STO) Single-crystal Substrates

Here, we demonstrate a method of coating ferromagnetic La0.67Sr0.33MnO3 (LSMO) nanoparticles on (001) SrTiO3 (STO) single-crystal substrates by radio frequency (RF) magnetron sputtering. LSMO nanoparticles were deposited with diameters from 10 to 20 nm and heights between 20 and 50 nm. At the same time, (Gd) Ba2Cu3O7&#8722;&#948; ((Gd) BCO) films were fabricated on both undecorated and LSMO nanoparticle decorated STO substrates using RF magnetron sputtering. This report also describes the properties of GdBa2Cu3O7&#8722;&#948;/ La0.67Sr0.33MnO3 quasi-bilayer films structures (e.g., crystalline phase, morphology, chemical composition); magnetization, magneto-transport, and superconducting transport properties were also evaluated.

Radio Frequency Magnetron Sputtering of GdBa2Cu3O7ÃƒÆ’Ã‚Â¢Ãƒâ€¹Ã¢â‚¬Â 'ÃƒÆ’Ã…Â½ Â´/ La0.67Sr0.33MnO3 Quasi-bilayer Films on SrTiO3 STO Single-crystal Substrates

Here, we present a protocol to grow LSMO nanoparticles and (Gd) BCO films on (001) SrTiO3 (STO) single-crystal substrates by radio frequency (RF)-sputtering.

Here, we demonstrate a method of coating ferromagnetic La0.67Sr0.33MnO3 (LSMO) nanoparticles on (001) SrTiO3 (STO) single-crystal substrates by radio ...

A 100 KW Class Applied-field Magnetoplasmadynamic Thruster

Applied-field magnetoplasmadynamic thrusters (AF-MPD thrusters) are hybrid accelerators in which electromagnetic and gas dynamic processes accelerate plasma to high speed; they have considerable potential for future space applications with the significant advantages of high specific impulse and thrust density. In this paper, we present a series of protocols for designing and manufacturing a 100 kW class of AF-MPD thruster with water-cooling structures, a 130 V maximum discharge voltage, a 800 A maximum discharge current, and a 0.25 T maximum strength of magnetic field. A hollow tantalum tungsten cathode acts as the only propellant inlet to inhibit the radial discharge, and it is positioned axially at the rear of the anode in order to relieve anode starvation. A cylindrical divergent copper anode is employed to decrease anode power deposition, where the length has been reduced to decrease the wall-plasma connecting area. Experiments utilized a vacuum system that can achieve a working vacuum of 0.01 Pa for a total propellant mass flow rate lower than 40 mg/s and a target thrust stand. The thruster tests were carried out to measure the effects of the working parameters such as propellant flow rates, the discharge current, and the strength of applied magnetic field on the performance and to allow appropriate analysis. The thruster could be operated continuously for significant periods of time with little erosion on the hollow cathode surface. The maximum power of the thruster is 100 kW, and the performance of this water-cooled configuration is comparable with that of thrusters reported in the literature.

The goal of this protocol is to introduce the design of a 100 kW class applied-field magnetoplasmadynamic thruster and relevant experimental methods.

Applied-field magnetoplasmadynamic thrusters (AF-MPD thrusters) are hybrid accelerators in which electromagnetic and gas dynamic processes accelerate ...

O-cresol Concentration Online Measurement Based On Near Infrared Spectroscopy Via Partial Least Square Regression

Unlike macroscopic process variables, near-infrared spectroscopy provides process information at the molecular level and can significantly improve the prediction of the components in industrial processes. The ability to record spectra for solid and liquid samples without any pretreatment is advantageous and the method is widely used. However, the disadvantages of analyzing high-dimensional near-infrared spectral data include information redundancy and multicollinearity of the spectral data. Thus, we propose to use partial least squares regression method, which has traditionally been used to reduce the data dimensionality and eliminate the collinearity between the original features. We implement the method for predicting the o-cresol concentration during the production of polyphenylene ether. The proposed approach offers the following advantages over component regression prediction methods: 1) partial least squares regression solves the multicollinearity problem of the independent variables and effectively avoids overfitting, which occurs in a regression analysis due to the high correlation between the independent variables; 2) the use of the near-infrared spectra results in high accuracy because it is a non-destructive and non-polluting method to obtain information at microscopic and molecular scales.

The protocol describes a method of predicting o-cresol concentration during the production of polyphenylene ether using near-infrared spectroscopy and partial least squares regression. To describe the process more clearly and completely, an example of predicting the o-cresol concentration during the production of polyphenylene is used to clarify the steps.

Unlike macroscopic process variables, near-infrared spectroscopy provides process information at the molecular level and can significantly improve the ...

Online Virtual Reality Networked Control Laboratory Applied in Control Engineering Education

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Free-form Light Actuators — Fabrication and Control of Actuation in Microscopic Scale