Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
5.2
3.0
Journals
Micromachines
Special Issues
Ocean MEMS and Related Technology
share announcement

Ocean MEMS and Related Technology

A special issue of Micromachines (ISSN 2072-666X). This special issue belongs to the section "E：Engineering and Technology".

Deadline for manuscript submissions: closed (30 June 2022) | Viewed by 39067

Special Issue Editors

Prof. Dr. Shizhi Qian

E-Mail Website
Guest Editor
Department of Mechanical and Aerospace Engineering, Old Dominion University, Norfolk, VA 23529, USA
Interests: micro/nanofluidics; non-Newtonian fluidics; transport phenomena in micro and nanoscales
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Teng Zhou

E-Mail Website
Guest Editor
Mechanical and Electrical Engineering College, Hainan University, Haikou 570228, China
Interests: micro/nanofluidics; electrokinetics; ocean microfluidic application
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Ocean MEMS is a fast-expanding field with many applications ranging from various MEMS sensors to energy-conversion devices. Ocean MEMS is important because of its miniaturization, low power consumption, and high integration. For example, MEMS-based instruments have been developed for measuring the conductivity, temperature, and pressure of seawater in real time. Some MEMS devices have been used to detect and separate heavy metal ions, ocean microorganisms, and other components in seawater. In addition, some systems have been developed to extract minerals such as sodium, potassium, and uranium, and to desalinate seawater. Ocean MEMS has also been used for ocean energy conversion. We invite papers related to ocean MEMS, including both fundamental studies and those on device/system development. We look forward to receiving your papers.

Prof. Dr. Shizhi Qian
Prof. Dr. Teng Zhou
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Micromachines is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • ocean MEMS
  • microsensors
  • ions/microorganisms detection
  • energy conversion
  • microfluidics

Benefits of Publishing in a Special Issue

  • Ease of navigation: Grouping papers by topic helps scholars navigate broad scope journals more efficiently.
  • Greater discoverability: Special Issues support the reach and impact of scientific research. Articles in Special Issues are more discoverable and cited more frequently.
  • Expansion of research network: Special Issues facilitate connections among authors, fostering scientific collaborations.
  • External promotion: Articles in Special Issues are often promoted through the journal's social media, increasing their visibility.
  • e-Book format: Special Issues with more than 10 articles can be published as dedicated e-books, ensuring wide and rapid dissemination.

Further information on MDPI's Special Issue polices can be found here.

Published Papers (16 papers)

Download All Papers
Order results
Result details
Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:

Research

11 pages, 1945 KiB  
Article
Design and Modeling of a Microfluidic Coral Polyps Culture Chip with Concentration and Temperature Gradients
by Shizheng Zhou, Edgar S. Fu, Bingbing Chen and Hong Yan
Micromachines 2022, 13(6), 832; https://doi.org/10.3390/mi13060832 - 26 May 2022
Cited by 3 | Viewed by 2293
Abstract
Traditional methods of cultivating polyps are costly and time-consuming. Microfluidic chip technology makes it possible to study coral polyps at the single-cell level, but most chips can only be analyzed for a single environmental variable. In this work, we addressed these issues by [...] Read more.
Traditional methods of cultivating polyps are costly and time-consuming. Microfluidic chip technology makes it possible to study coral polyps at the single-cell level, but most chips can only be analyzed for a single environmental variable. In this work, we addressed these issues by designing a microfluidic coral polyp culture chip with a multi-physical field for multivariable analyses and verifying the feasibility of the chip through numerical simulation. This chip used multiple serpentine structures to generate the concentration gradient and used a circuit to form the Joule effect for the temperature gradient. It could generate different temperature gradients at different voltages for studying the growth of polyps in different solutes or at different temperatures. The simulation of flow field and temperature showed that the solute and heat could be transferred evenly and efficiently in the chambers, and that the temperature of the chamber remained unchanged after 24 h of continuous heating. The thermal expansion of the microfluidic chip was low at the optimal culture temperature of coral polyps, which proves the feasibility of the use of the multivariable microfluidic model for polyp culture and provides a theoretical basis for the actual chip processing. Full article
(This article belongs to the Special Issue Ocean MEMS and Related Technology)
►▼ Show Figures

Figure 1

16 pages, 4398 KiB  
Article
Automatic Walking Method of Construction Machinery Based on Binocular Camera Environment Perception
by Zhen Fang, Tianliang Lin, Zhongshen Li, Yu Yao, Chunhui Zhang, Ronghua Ma, Qihuai Chen, Shengjie Fu and Haoling Ren
Micromachines 2022, 13(5), 671; https://doi.org/10.3390/mi13050671 - 25 Apr 2022
Cited by 5 | Viewed by 2108
Abstract
In this paper, we propose an end-to-end automatic walking system for construction machinery, which uses binocular cameras to capture images of construction machinery for environmental perception, detects target information in binocular images, estimates the relative distance between the current target and cameras, and [...] Read more.
In this paper, we propose an end-to-end automatic walking system for construction machinery, which uses binocular cameras to capture images of construction machinery for environmental perception, detects target information in binocular images, estimates the relative distance between the current target and cameras, and predicts the real-time control signal of construction machinery. This system consists of two parts: the binocular recognition ranging model and the control model. Objects within 5 m can be quickly detected by the recognition ranging model, and at the same time, the distance of the object can be accurately ranged to ensure the full perception of the surrounding environment of the construction machinery. The distance information of the object, the feature information of the binocular image, and the control signal of the previous stage are sent to the control model; then, the prediction of the control signal of the construction machinery can be output in the next stage. In this way, the automatic walking experiment of the construction machinery in a specific scenario is completed, which proves that the model can control the machinery to complete the walking task smoothly and safely. Full article
(This article belongs to the Special Issue Ocean MEMS and Related Technology)
►▼ Show Figures

Figure 1

16 pages, 4834 KiB  
Article
Effect of Combustion Chamber Geometrical Parameters on the Decomposition and Combustion Characteristics of an ADN-Based Thruster
by Yangyang Hou, Yusong Yu, Xuhui Liu and Jie Cao
Micromachines 2022, 13(4), 605; https://doi.org/10.3390/mi13040605 - 12 Apr 2022
Cited by 10 | Viewed by 2285
Abstract
In this paper, numerical simulations were used to study the decomposition and combustion processes inside the 0.2 N-class ADN-based thruster, and the effects of two geometrical parameters (length and diameter) of the combustion chamber on the combustion performance were evaluated. The decomposition and [...] Read more.
In this paper, numerical simulations were used to study the decomposition and combustion processes inside the 0.2 N-class ADN-based thruster, and the effects of two geometrical parameters (length and diameter) of the combustion chamber on the combustion performance were evaluated. The decomposition and combustion processes of the thruster were simulated using a reduced chemical reaction mechanism with 22 components and 20 reactions steps. According to the distribution of the basic physical fields, the variation patterns of the pressure field, velocity field, temperature field, and key component parameters caused by different combustion chamber geometrical parameters were observed and analyzed. The results show that the specific impulse and thrust of the thruster increased and then decreased with the increase of the combustion chamber diameter. When the combustion chamber diameter is 7.9 mm, the specific impulse reaches the maximum value of 206.6 s. Additionally, the specific impulse increased from 186 s to 206 s when the combustion chamber length was changed from 7 mm to 11 mm; the specific impulse increased gradually but not significantly, and the growth trend started to flatten out. The results from the paper can serve as a reference for the design and vacuum testing of an ADN-based thruster. Full article
(This article belongs to the Special Issue Ocean MEMS and Related Technology)
►▼ Show Figures

Figure 1

13 pages, 5034 KiB  
Article
Effects of Heat Reflux on Two-Phase Flow Characteristics in a Capillary of the ADN-Based Thruster
by Zhuan Yan, Xuhui Liu, Yusong Yu, Jie Cao, Xiaodan Liu and Shurui Zhang
Micromachines 2022, 13(4), 597; https://doi.org/10.3390/mi13040597 - 10 Apr 2022
Cited by 4 | Viewed by 2036
Abstract
During the working process of the ADN-based thruster, continuously, heat generated by the chemical reaction in the combustion chamber will transfer along the upstream capillary, the propellant in the capillary continuously absorbs heat under the effect of heat transfer from the wall and [...] Read more.
During the working process of the ADN-based thruster, continuously, heat generated by the chemical reaction in the combustion chamber will transfer along the upstream capillary, the propellant in the capillary continuously absorbs heat under the effect of heat transfer from the wall and undergoes a phase change when the saturation temperature is reached. In this study, effects of the downstream heating temperature (623 K to 923 K) on mass flow rate and pressure change in the capillary were investigated based on the established test platform. Simultaneously, the VOF (volume of fraction) model, and the Lee phase transition model coupled with the Navier–Stokes method was utilized to simulate the spatial distribution of the gas-liquid propellant in the capillary. The results show that the ADN-based propellant firstly formed bubbles on the inner wall surface near the exit of the capillary, and these vapor bubbles moved and grew upstream along the capillary. Due to the cooling effect of the ADN-based propellant inflow, the temperature distribution of the front chamber and capillary gradually reached equilibrium. Bubbles were constantly generated in the capillary, and as the heat reflux intensified, the total volume of bubbles in the capillary continued increasing. Single-phase flow, annular flow, wave flow, and segment plug flow appeared sequentially along the axial direction of the capillary, and the proportion of gas phase volume fraction at the capillary outlet section gradually increased. Full article
(This article belongs to the Special Issue Ocean MEMS and Related Technology)
►▼ Show Figures

Figure 1

8 pages, 1949 KiB  
Article
A Microfluidic PET-Based Electrochemical Glucose Sensor
by Linda Yang, Zheng Zhang and Xin Wang
Micromachines 2022, 13(4), 552; https://doi.org/10.3390/mi13040552 - 30 Mar 2022
Cited by 6 | Viewed by 3176
Abstract
Paper-based microfluidic sensors have gained increased attention in the field of analytical assays in recent years due to their self-driven nature, ease of preparation, high integration, low reagent consumption, and low cost. However, paper-based microfluidic sensors still have many deficiencies when it comes [...] Read more.
Paper-based microfluidic sensors have gained increased attention in the field of analytical assays in recent years due to their self-driven nature, ease of preparation, high integration, low reagent consumption, and low cost. However, paper-based microfluidic sensors still have many deficiencies when it comes to the detection of some specific detectors such as blood glucose. For example, the processing procedure for microfluidic channels is tedious, the sensor electrodes are easily damaged by bending, and they can only be used as disposable products. To solve the above problems, a PET-based microfluidic sensor was proposed in this paper, the performance of which was tested with glucose as the target detector. The experimental results showed that the analytical performance of this sensor is comparable to that of existing commercial glucose meters. This work provides implications for the substrate selection of microfluidic chips for some biochemical analyses. Full article
(This article belongs to the Special Issue Ocean MEMS and Related Technology)
►▼ Show Figures

Figure 1

11 pages, 3382 KiB  
Article
In Situ Sensor for the Detection of Oil Spill in Seawater Using Microwave Techniques
by Aliyu Dala and Tughrul Arslan
Micromachines 2022, 13(4), 536; https://doi.org/10.3390/mi13040536 - 29 Mar 2022
Cited by 6 | Viewed by 2320
Abstract
Nearly 30% of oil drilled globally is done offshore. Oil spillage offshore has far-reaching consequences on the environment, aquatic lives, and livelihoods as it was evident in the Deepwater Horizon and Bonga oil spills. A novel microwave in situ oil spill sensor was [...] Read more.
Nearly 30% of oil drilled globally is done offshore. Oil spillage offshore has far-reaching consequences on the environment, aquatic lives, and livelihoods as it was evident in the Deepwater Horizon and Bonga oil spills. A novel microwave in situ oil spill sensor was developed in this work. The device is comprised of two polydimethylsiloxane (PDMS)-encapsulated ultra-wideband underwater microwave trefoil antennas enclosed in a Faraday cage with one serving as the receiving antenna and the other as the transmitting antenna. Heavy aromatic-naphthenic Azeri crude oil was used as an inclusion in the seawater host medium. Substantial changes in the measured reflection (S11) and transmission (S21) coefficients were observed as the medium was adulterated with crude oil starting from 200 MHz to around 2500 MHz. The changes in the dielectric properties of the media resulted in changes in both the S11 and S21 signifying and detecting an occurrence of the oil spillage. Thus, by employing radio frequencies, oil spillage was detected using the in situ monitoring device in seawater. Full article
(This article belongs to the Special Issue Ocean MEMS and Related Technology)
►▼ Show Figures

Figure 1

16 pages, 7984 KiB  
Article
Pipeline Vibration Control Using Magnetorheological Damping Clamps under Fuzzy–PID Control Algorithm
by Fei Gong, Songlin Nie, Hui Ji, Ruidong Hong, Fanglong Yin and Xiaopeng Yan
Micromachines 2022, 13(4), 531; https://doi.org/10.3390/mi13040531 - 28 Mar 2022
Cited by 10 | Viewed by 2678
Abstract
Aiming at the problem of low-frequency vibration of the hydraulic pipeline, a new type of semi-active damping magnetorheological (MR) damping clamp structure is designed. The structure size and material of the MR damping clamp were determined. The control model of the vibration damping [...] Read more.
Aiming at the problem of low-frequency vibration of the hydraulic pipeline, a new type of semi-active damping magnetorheological (MR) damping clamp structure is designed. The structure size and material of the MR damping clamp were determined. The control model of the vibration damping system was established, and the control method combining fuzzy control and Proportional-Integral-Derivative (PID) control was used to carry out the numerical simulation, which proved that the fuzzy–PID control algorithm is effective and stable. The results show that the MR damping clamp proposed in this paper can effectively suppress the axial displacement and acceleration of the hydraulic pipeline in the excitation frequency range of 1 Hz~10 Hz. This research provides a new technical approach for low-frequency vibration control of hydraulic pipelines. Full article
(This article belongs to the Special Issue Ocean MEMS and Related Technology)
►▼ Show Figures

Figure 1

12 pages, 7655 KiB  
Article
Effect of Upstream Valve Opening Process on Dynamic Spray Atomization of Bipropellant Thruster Injector
by Zhen Zhang, Yusong Yu and Jie Cao
Micromachines 2022, 13(4), 527; https://doi.org/10.3390/mi13040527 - 27 Mar 2022
Cited by 2 | Viewed by 2302
Abstract
In order to develop a new generation of intelligent satellites, fast-response bipropellant thrusters are required to work in minimum impulse mode without limitation. When a valve is opening, the fluctuation affects downstream spray atomization at the injector, which determines the thruster’s impulse performance, [...] Read more.
In order to develop a new generation of intelligent satellites, fast-response bipropellant thrusters are required to work in minimum impulse mode without limitation. When a valve is opening, the fluctuation affects downstream spray atomization at the injector, which determines the thruster’s impulse performance, involving combustion efficiency and impulse repeatability. Accordingly, the spray atomization under impulse working condition was investigated to optimize the thruster’s dynamic response. The effects of propellant property, switch speed, valve stroke, and throttle orifice layout are respectively compared in simulation cases using OpenFOAM. The fluctuating flowrate caused by valve opening was simulated and then used as boundary conditions for downstream spray. Among these factors, orifice layout plays the most significant roles in transient spray development. Compared with MMH spray, NTO spray from outer swirl injector is more sensitive to upstream fluctuation. When the upstream flowrate stabilizes faster, the atomization stability can also be enhanced, thereby improving the impulse repeatability of thrusters in combustion. This experimental result was in good agreement with the simulation, thereby showing that only when atomization of MMH spray and NTO spray both develop into a steady state within 5 ms after valve opening can the impulse performance be reliably achieved. Full article
(This article belongs to the Special Issue Ocean MEMS and Related Technology)
►▼ Show Figures

Figure 1

11 pages, 40291 KiB  
Article
Experimental Research on Microwave Ignition and Combustion Characteristics of ADN-Based Liquid Propellant
by Jiannan Shen, Yusong Yu, Xuhui Liu and Jie Cao
Micromachines 2022, 13(4), 510; https://doi.org/10.3390/mi13040510 - 25 Mar 2022
Cited by 10 | Viewed by 2604
Abstract
Microwave ignition has attracted much attention due to its advantages of reliable ignition, large ignition area and cold-start capability. In this paper, the experimental method is used to explore the ignition ability of the microwave device to ADN-based liquid propellant. Additionally, we discuss [...] Read more.
Microwave ignition has attracted much attention due to its advantages of reliable ignition, large ignition area and cold-start capability. In this paper, the experimental method is used to explore the ignition ability of the microwave device to ADN-based liquid propellant. Additionally, we discuss the influence of the inlet power and rate of propellant injected into the ignition system on the height of the combustion jet and the combustion temperature. In the experiment, a microwave-assisted ignition system was established based on a special microwave resonant cavity. The liquid propellant and working gas were sprayed into the resonator cavity through the hollow straight tube beneath the resonant cavity. The test results show that the device can ignite the propellant under the condition of 800 W input power, which proves the feasibility of the microwave ignition device for ADN-based liquid propellant. Microwave power has some influence on the flame spray height at the initial stage of combustion. The spray height at 2000 W is increased by 55.7% in comparison to 1000 W. In the stable combustion stage, the input power has a very significant increase in the average temperature of the flame, which is increased by 25%. The combustion is relatively better when the propellant flow rate is 30 mL/min, and the height of the flame spray increases by 25.2%. The increase in throughput did not have a significant impact on the flame temperature. Full article
(This article belongs to the Special Issue Ocean MEMS and Related Technology)
►▼ Show Figures

Figure 1

16 pages, 4940 KiB  
Article
Quality Study and Numerical Simulation Analysis of Solid–Liquid Two-Phase Magnetic Fluid Polishing Seven-Order Variable-Diameter Pipe
by Jing Guo, Lin Gui, Wei Hou, Liwei Sun, Yang Liu and Junye Li
Micromachines 2022, 13(4), 500; https://doi.org/10.3390/mi13040500 - 23 Mar 2022
Cited by 1 | Viewed by 1702
Abstract
Variable-diameter pipe parts have been widely used in the automobile industry, aerospace industry, and other fields. To enhance the surface quality of variable-diameter pipe and explore the effect of solid–liquid two-phase magnetic fluid (SLTPMF) on polishing, in this paper, the seven-order variable-diameter pipe [...] Read more.
Variable-diameter pipe parts have been widely used in the automobile industry, aerospace industry, and other fields. To enhance the surface quality of variable-diameter pipe and explore the effect of solid–liquid two-phase magnetic fluid (SLTPMF) on polishing, in this paper, the seven-order variable-diameter pipe with symmetrical structure is taken as the research object to carry out experimental research and numerical simulation. The experimental research shows that the best surface roughness is reduced by an order of magnitude to Ra 0.054 μm. The solid–liquid two-phase magnetic fluid polishing (SLTPMFP) technology has reliability and superiority in improving the roughness of variable-diameter pipe parts. The simulation results show that the wall shear stress of solid–liquid two-phase magnetic fluid on the wall surface of the workpiece affects the improvement of roughness. The greater the wall shear force, the better the surface roughness can be obtained. The velocity and dynamic pressure cloud diagram show that the velocity and dynamic pressure on the center axis of the workpiece first increase and then decrease with the flow of the magnetic fluid. The velocity and dynamic pressure on the near wall surface are reduced due to the shear collision with the workpiece. This work can provide technical and theoretical support for the actual production of SLTPMF precision polishing. Full article
(This article belongs to the Special Issue Ocean MEMS and Related Technology)
►▼ Show Figures

Figure 1

21 pages, 8749 KiB  
Article
Adaptive Sliding Mode Disturbance Observer and Deep Reinforcement Learning Based Motion Control for Micropositioners
by Shiyun Liang, Ruidong Xi, Xiao Xiao and Zhixin Yang
Micromachines 2022, 13(3), 458; https://doi.org/10.3390/mi13030458 - 17 Mar 2022
Cited by 5 | Viewed by 2861
Abstract
The motion control of high-precision electromechanitcal systems, such as micropositioners, is challenging in terms of the inherent high nonlinearity, the sensitivity to external interference, and the complexity of accurate identification of the model parameters. To cope with these problems, this work investigates a [...] Read more.
The motion control of high-precision electromechanitcal systems, such as micropositioners, is challenging in terms of the inherent high nonlinearity, the sensitivity to external interference, and the complexity of accurate identification of the model parameters. To cope with these problems, this work investigates a disturbance observer-based deep reinforcement learning control strategy to realize high robustness and precise tracking performance. Reinforcement learning has shown great potential as optimal control scheme, however, its application in micropositioning systems is still rare. Therefore, embedded with the integral differential compensator (ID), deep deterministic policy gradient (DDPG) is utilized in this work with the ability to not only decrease the state error but also improve the transient response speed. In addition, an adaptive sliding mode disturbance observer (ASMDO) is proposed to further eliminate the collective effect caused by the lumped disturbances. The micropositioner controlled by the proposed algorithm can track the target path precisely with less than 1 μm error in simulations and actual experiments, which shows the sterling performance and the accuracy improvement of the controller. Full article
(This article belongs to the Special Issue Ocean MEMS and Related Technology)
►▼ Show Figures

Figure 1

17 pages, 7117 KiB  
Article
Machine Vision-Based Method for Measuring and Controlling the Angle of Conductive Slip Ring Brushes
by Junye Li, Jun Li, Xinpeng Wang, Gongqiang Tian and Jingfeng Fan
Micromachines 2022, 13(3), 447; https://doi.org/10.3390/mi13030447 - 16 Mar 2022
Cited by 5 | Viewed by 2292
Abstract
The conductive slip ring is used for power or signal transmission between two objects rotating relative to each other. It has become an essential part of modern industrial development. In traditional automated production measurements, the typical method is to use calipers, goniometers, or [...] Read more.
The conductive slip ring is used for power or signal transmission between two objects rotating relative to each other. It has become an essential part of modern industrial development. In traditional automated production measurements, the typical method is to use calipers, goniometers, or angle gauges to measure a parameter of the workpiece several times and then average it. These inspection means have low measurement accuracy and slow measurement speed, and measurement data cannot be processed in a timely manner. A machine vision-based method for measuring and controlling the angle of the brushes is proposed for this problem. First, the brush angle forming device was built for the conductive slip ring brush wire, forming the principle and rebound characteristics. Then, machine vision and image processing algorithms were applied to measure the key parts of the conductive slip ring brushes. The data of the forming angle value and rebound angle value were obtained during the forming process of the brush wire angle. Finally, a pre-compensation model for the brush filament rebound was developed and validated based on the curve fitting method. The test results show that the error of the angle measurement is within 0.05°. The average error of the measured rebound angle and the calculated rebound angle of the brush filament pre-compensation model was 0.112°, which verifies the correctness of the pre-compensation model. The forming angle can be controlled more precisely, and the contact performance between the brush wire and the ring body can be improved effectively. This method has the potential to be extended to engineering applications. Full article
(This article belongs to the Special Issue Ocean MEMS and Related Technology)
►▼ Show Figures

Figure 1

19 pages, 136474 KiB  
Article
Study on the Mechanical Properties of Monocrystalline Germanium Crystal Planes Based on Molecular Dynamics
by Linsen Song, Juncheng Song, Junye Li, Tiancheng Wang and Zhenguo Zhao
Micromachines 2022, 13(3), 441; https://doi.org/10.3390/mi13030441 - 15 Mar 2022
Cited by 4 | Viewed by 2177
Abstract
Nanoindentation and atomistic molecular dynamics simulations of the loading surface of monocrystalline germanium were used to investigate the evolution of the key structure, the force model, the temperature, the potential, and the deformable layer thickness. The mechanical characteristics of typical crystal planes (001), [...] Read more.
Nanoindentation and atomistic molecular dynamics simulations of the loading surface of monocrystalline germanium were used to investigate the evolution of the key structure, the force model, the temperature, the potential, and the deformable layer thickness. The mechanical characteristics of typical crystal planes (001), (110), and (111) of the crystal system were compared under load. It was observed that the hardness and stiffness of the (110) plane were greatest among the three crystal planes, whereas the hardness and stiffness of the (111) plane were lowest. Moreover, the deformation layers at the ends of both planes were basically flat. The processing efficiency of the (111) surface was higher; thus, the (111) surface was considered the best loading surface. It was concluded that the subsurface defects of the monocrystalline germanium (111) plane were smaller and the work efficiency was higher during the processing of monocrystalline germanium, making it ideal for monocrystalline germanium ultra-precision processing. Full article
(This article belongs to the Special Issue Ocean MEMS and Related Technology)
►▼ Show Figures

Figure 1

18 pages, 8660 KiB  
Article
Numerical Analysis of Multi-Angle Precision Microcutting of a Single-Crystal Copper Surface Based on Molecular Dynamics
by Jianhe Liu, Liguang Dong, Junye Li, Kun Dong, Tiancheng Wang and Zhenguo Zhao
Micromachines 2022, 13(2), 263; https://doi.org/10.3390/mi13020263 - 6 Feb 2022
Cited by 2 | Viewed by 1697
Abstract
The molecular dynamics method was used to study the removal mechanism of boron nitride particles by multi-angle microcutting of single-crystal copper from the microscopic point of view. The mechanical properties and energy conversion characteristics of single-crystal copper during microcutting were analyzed and the [...] Read more.
The molecular dynamics method was used to study the removal mechanism of boron nitride particles by multi-angle microcutting of single-crystal copper from the microscopic point of view. The mechanical properties and energy conversion characteristics of single-crystal copper during microcutting were analyzed and the atomic displacement and dislocation formation in the microcutting process are discussed. The research results showed that during the energy transfer between atoms during the microcutting process of boron nitride particles, the crystal lattice of the single-crystal copper atom in the cutting extrusion region was deformed and displaced, the atomic temperature and thermal motion in the contact area between boron nitride particles and Newtonian layer of workpiece increased, the single-crystal copper atom lattice was defective, and the atomic arrangement structure was destroyed and recombined. The interface of different crystal structures formed a dislocation structure and produced plastic deformation. With the increase of the impact cutting angle, the dislocation density inside the crystal increased, the defect structure increased and the surface quality of the workpiece decreased. To protect the internal structure of the workpiece and improve the material removal rate, a smaller cutting angle should be selected for the abrasive flow microcutting function, which can reduce the formation of an internal defect structure and effectively improve the quality of abrasive flow precision machining. The research conclusions can provide a theoretical basis and technical support for the development of precision abrasive flow processing technology. Full article
(This article belongs to the Special Issue Ocean MEMS and Related Technology)
►▼ Show Figures

Figure 1

13 pages, 5301 KiB  
Article
An Impedance Sensor for Distinguishing Multi-Contaminants in Hydraulic Oil of Offshore Machinery
by Haotian Shi, Dian Huo, Hongpeng Zhang, Wei Li, Yuqing Sun, Guobin Li and Haiquan Chen
Micromachines 2021, 12(11), 1407; https://doi.org/10.3390/mi12111407 - 17 Nov 2021
Cited by 4 | Viewed by 2326
Abstract
The cleanliness of hydraulic oil can reflect the service life of the oil and the wear state of hydraulic machinery. An impedance sensor is proposed to distinguish multi-contaminants in hydraulic oil. The impedance sensor has two detection modes: the inductance-resistance mode is used [...] Read more.
The cleanliness of hydraulic oil can reflect the service life of the oil and the wear state of hydraulic machinery. An impedance sensor is proposed to distinguish multi-contaminants in hydraulic oil. The impedance sensor has two detection modes: the inductance-resistance mode is used to detect metal debris, and the capacitance mode is used to distinguish water droplets and air bubbles. By adding a built-in silicon steel strip and an external silicon steel strip with high magnetic permeability, the distribution area, strength, and uniformity of the magnetic field are enhanced to improve the detection sensitivity under inductance and resistance parameters. In addition, the silicon steel strips are used as electrode plates to introduce capacitance parameter detection. The experimental results show that the resistance detection method based on coil successfully improves the detection ability for non-ferromagnetic metal debris. The impedance sensor for distinguishing multi-contaminants in hydraulic oil can provide technical support for fault diagnosis of offshore hydraulic machinery. Full article
(This article belongs to the Special Issue Ocean MEMS and Related Technology)
►▼ Show Figures

Graphical abstract

10 pages, 2779 KiB  
Article
Enzyme Method-Based Microfluidic Chip for the Rapid Detection of Copper Ions
by Binfeng Yin, Xinhua Wan, Changcheng Qian, A. S. M. Muhtasim Fuad Sohan, Teng Zhou and Wenkai Yue
Micromachines 2021, 12(11), 1380; https://doi.org/10.3390/mi12111380 - 10 Nov 2021
Cited by 14 | Viewed by 2326
Abstract
Metal ions in high concentrations can pollute the marine environment. Human activities and industrial pollution are the causes of Cu2+ contamination. Here, we report our discovery of an enzyme method-based microfluidic that can be used to rapidly detect Cu2+ in seawater. [...] Read more.
Metal ions in high concentrations can pollute the marine environment. Human activities and industrial pollution are the causes of Cu2+ contamination. Here, we report our discovery of an enzyme method-based microfluidic that can be used to rapidly detect Cu2+ in seawater. In this method, Cu2+ is reduced to Cu+ to inhibit horseradish peroxidase (HRP) activity, which then results in the color distortion of the reaction solution. The chip provides both naked eye and spectrophotometer modalities. Cu2+ concentrations have an ideal linear relationship, with absorbance values ranging from 3.91 nM to 256 μM. The proposed enzyme method-based microfluidic chip detects Cu2+ with a limit of detection (LOD) of 0.87 nM. Other common metal ions do not affect the operation of the chip. The successful detection of Cu2+ was achieved using three real seawater samples, verifying the ability of the chip in practical applications. Furthermore, the chip realizes the functions of two AND gates in series and has potential practical implementations in biochemical detection and biological computing. Full article
(This article belongs to the Special Issue Ocean MEMS and Related Technology)
►▼ Show Figures

Figure 1

Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:
 
Displaying articles 1-16
Back to TopTop