Electrochemical Seismometer Research Articles

A Field Self-Adjusting Method for Electrochemical Seismometer Based on Dynamic Feedback Network

Based on the dynamic force feedback network, a fast self-adjusting method with field working ability is designed for the electrochemical seismometer. Dynamic feedback network provides the characteristics of adaptability in complex environments for the seismometer. And the reusage of feedback source provides a very low-cost self-testing ability without a laboratory environment or any external equipment. To implement this method, an analytical adjusting algorithm is derived. The simulation shows the adjusting adaptability for arbitrary targets and multiple electrochemical seismometers. A prototype is developed to verify the method, the prototype can be adjusted to the optimal second-order system under arbitrarily cutoff frequency between 0.5Hz and 1Hz, and the self-adjusting process finished within 10 minutes.

MEMS-Based Integrated Triaxial Electrochemical Seismometer.

This paper presents a micro-electromechanical systems (MEMS)-based integrated triaxial electrochemical seismometer, which can detect three-dimensional vibration. By integrating three axes, the integrated triaxial electrochemical seismometer is characterized by small volume and high symmetry. The numerical simulation results inferred that the integrated triaxial electrochemical seismometer had excellent independence among three axes. Based on the experimental results, the integrated triaxial electrochemical seismometer had the advantage of small axial crosstalk and could detect vibration in arbitrary directions. Furthermore, compared with the uniaxial electrochemical seismometer, the integrated triaxial electrochemical seismometer had similar sensitivity curves ranging from 0.01 to 100 Hz. In terms of random ground motion response, high consistencies between the developed integrated triaxial electrochemical seismometer and the uniaxial electrochemical seismometer could be easily observed, which indicated that the developed integrated triaxial electrochemical seismometer produced comparable noise levels to those of the uniaxial electrochemical seismometer. These results validated the performance of the integrated triaxial electrochemical seismometer, which has a good prospect in the field of deep geophysical exploration and submarine seismic monitoring.

MEMS-Based Electrochemical Seismometer with a Sensing Unit Integrating Four Electrodes.

This paper presents a new process to fabricate a sensing unit of electrochemical seismometers using only one silicon–glass–silicon bonded wafer. By integrating four electrodes on one silicon–glass–silicon bonded wafer, the consistency of the developed sensing unit was greatly improved, benefiting from the high alignment accuracy. Parameter designs and simulations were carried out based on this sensing unit, which indicated that the sensitivities of the developed electrochemical seismometer decreased with the decrease in the number of flow holes in the sensing unit, and the initial stabilization time decreased gradually with the decrease in the thickness of the glass layer. Based on experimental results of four devices, the peak sensitivity was quantified as 5345.45 ± 43.78 V/(m/s) at 2 Hz, which proved high consistency of the fabricated electrochemical seismometer. In terms of the responses to random ground motions, high consistencies between the developed electrochemical seismometer and the commercial counterpart of CME6011 (R-sensors, Moscow, Russia) were found, where the developed electrochemical seismometer produced comparable noise levels to those of CME6011. These results validated the performance of the device and it may function as an effective tool for a variety of applications.

MEMS-Based Electrochemical Seismometer Relying on a CAC Integrated Three-Electrode Structure

This study developed a MEMS-based electrochemical seismometer relying on a cathode–anode–cathode (CAC) integrated three-electrode structure where two cathodes were positioned on two surfaces of a silicon wafer, while one anode was positioned on the sidewalls of the through holes of the silicon wafer. Device design and numerical simulations were conducted to model the functionality of the three-electrode structure in detecting vibration signals with the key geometrical parameters optimized. The CAC integrated three-electrode structure was then manufactured by microfabrication, which demonstrated a simplified fabrication process in comparison with conventional four-electrode structures. Device characterization shows that the sensitivity of the CAC microseismometer was an order of magnitude higher than that of the CME6011 (a commercially available four-electrode electrochemical seismometer), while the noise level was comparable. Furthermore, in response to random vibrations, a high correlation coefficient between the CAC and the CME6011 (0.985) was located, validating the performance of the developed seismometer. Thus, the developed electrochemical microseismometer based on an integrated three-electrode structure may provide a new perspective in seismic observations and resource explorations.

The Electrochemical Seismometer Based on Fine-Tune Sensing Electrodes for Undersea Exploration

This paper developed micro-electro-mechanical system (MEMS) based electrochemical seismometers featured with new structures of sensing electrodes for undersea exploration. In comparison to previously reported counterparts, the proposed sensing electrodes were featured with 1) simplification of the fabrication processes and 2) convenient control of the tiny space between anodes and cathodes by the adoption of insulating annuluses and make an increase in the sensitivities (e.g. 5200 V/(m/s) @1Hz). Based on forced-balanced feedback systems, the broadband seismometers were developed with the final bandwidth of 0.0083Hz-20Hz and achieves the sensitivity of 2000V/(m/s) with the noise level of 1.26(nm/s)/Hz <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1/2</sup> @1Hz (-178dB). Under the detection of a nature earthquake, the cross-correlation coefficients between the proposed seismometers and a local seismic station reach 0.95. As a proof-of-concept demonstration, the seismometers developed in this study were tested in a sea-trial, and shown to function well on a sea bed (e.g. 1000 m in depth) with cross-correlation coefficients between two devices quantified as 0.94.

Special Issue No. – 10, June, 2020 Journal &gt; Special Issue &gt; Special Issue No. – 10, June, 2020 &gt; Page 5 “Quantative Methods in Modern Science” organized by Academic Paper Ltd, Russia MORPHOLOGICAL AND ANATOMICAL FEATURES OF THE GENUS GAGEA SALISB., GROWING IN THE EAST KAZAKHSTAN REGION Authors: Zhamal T. Igissinova,Almash A. Kitapbayeva,Anargul S. Sharipkhanova,Alexander L. Vorobyev,Svetlana F. Kolosova,Zhanat

Special Issue No. – 10, June, 2020 Journal &gt; Special Issue &gt; Special Issue No. – 10, June, 2020 &gt; Page 5 “Quantative Methods in Modern Science” organized by Academic Paper Ltd, Russia MORPHOLOGICAL AND ANATOMICAL FEATURES OF THE GENUS GAGEA SALISB., GROWING IN THE EAST KAZAKHSTAN REGION Authors: Zhamal T. Igissinova,Almash A. Kitapbayeva,Anargul S. Sharipkhanova,Alexander L. Vorobyev,Svetlana F. Kolosova,Zhanat

Microelectromechanical System-Based Electrochemical Seismometers with Two Pairs of Electrodes Integrated on One Chip.

This paper presents microelectromechanical system (MEMS)-based electrochemical seismometers with two pairs of electrodes integrated on one chip. Both theoretical analysis and numerical simulations were conducted to reveal the working principle of the proposed electrochemical seismometers, finding that flow holes distributed on cathodes rather than anodes can produce significantly higher sensitivities. The proposed electrochemical seismometers were fabricated based on conventional micromachined processes with high fabrication repeatability. Sensitivity measurements of the proposed seismometers and their commercial counterpart of CME6011 were conducted, indicating the sensitivities of the proposed seismometer with flow holes on cathodes were two orders higher than the counterpart with flow holes on anodes and one order higher than CME6011 at dominant frequencies. Measurements of random ground motions based on the proposed seismometer with flow holes on cathodes and CME6011 were conducted, producing comparable noise levels without observable ground motions and high correlations in response to random events of ground motions. These results validated the functionality of the proposed electrochemical seismometers, which may contribute to seismic monitoring in the near future.

An Electrochemical, Low-Frequency Seismic Micro-Sensor Based on MEMS with a Force-Balanced Feedback System.

Electrochemical seismic sensors are key components in monitoring ground vibration, which are featured with high performances in the low-frequency domain. However, conventional electrochemical seismic sensors suffer from low repeatability due to limitations in fabrication and limited bandwidth. This paper presents a micro-fabricated electrochemical seismic sensor with a force-balanced negative feedback system, mainly composed of a sensing unit including porous sensing micro electrodes immersed in an electrolyte solution and a feedback unit including a feedback circuit and a feedback magnet. In this study, devices were designed, fabricated, and characterized, producing comparable performances among individual devices. In addition, bandwidths and total harmonic distortions of the proposed devices with and without a negative feedback system were quantified and compared as 0.005–20 (feedback) Hz vs. 0.3–7 Hz (without feedback), 4.34 ± 0.38% (without feedback) vs. 1.81 ± 0.31% (feedback)@1 Hz@1 mm/s and 3.21 ± 0.25% (without feedback) vs. 1.13 ± 0.19% (feedback)@5 Hz@1 mm/s (ndevice = 6, n represents the number of the tested devices), respectively. In addition, the performances of the proposed MEMS electrochemical seismometers with feedback were compared to a commercial electrochemical seismic sensor (CME 6011), producing higher bandwidth (0.005–20 Hz vs. 0.016–30 Hz) and lower self-noise levels (−165.1 ± 6.1 dB vs. −137.7 dB at 0.1 Hz, −151.9 ± 7.5 dB vs. −117.8 dB at 0.02 Hz (ndevice = 6)) in the low-frequency domain. Thus, the proposed device may function as an enabling electrochemical seismometer in the fields requesting seismic monitoring at the ultra-low frequency domain.

A High-Consistency Broadband MEMS-Based Electrochemical Seismometer With Integrated Planar Microelectrodes

This paper presents a broadband micro-electromechanical systems-based electrochemical seismometer with a new sensing unit composed of planar microelectrodes and perpendicular flow channels. The proposed sensing unit only needs three main microfabrication steps, leading to high consistency among devices which was quantified as 0.9978 ± 0.00050. Moreover, due to the new structure of the propose sensing unit, the raw device was featured with higher sensitivity [215.5 V/(m/s)], lower central working frequency (1 Hz), and wider working bandwidth (0.12–10.5 Hz) than previous reports. Based on the wide raw bandwidth, a broadband electrochemical seismometer was developed by the force balancing negative feedback with the final working bandwidth of 4.2 decades (0.0071–113 Hz). The linearity error and total harmonic distortion were both decreased by the feedback technology. In addition, the proposed devices demonstrated comparable self-noise level with the high-performance commercial counterpart “Trillium Compact.” Random seismic recording test was also conducted where the proposed device recorded a local earthquake with high consistency with the STS-2.5 deployed in the permanent station.

A MEMS Based Electrochemical Seismometer with Low Cost and Wide Working Bandwidth

This paper reports a MEMS based electrochemical seismometer featured with low cost and wide working bandwidth. In this study, a new sensing unit was proposed, in which a pair of ultra-thin electrodes with large reactive surface areas were integrated on corresponding silicon substrates, leading to 1) an decrease in cost and an increase in yield due to the simplified fabrication processes (e.g., only three standard microfabrication steps); and 2) an increase in the working bandwidth (0.14Hz -26.81Hz) based on the optimized geometrical parameters, compared to conventional electrochemical seismometers (0.47Hz -18.24Hz).

A micro electrochemical seismic sensor based on MEMS technologies

This paper presents the first-of-its-kind electrochemical seismic sensor where, a liquid proof mass (e.g., electrolyte solution) was used as the sensing element to translate environmental vibrations into active ion imbalances between electrodes, and therefore producing electrical current outputs. Theoretical analysis and numerical simulations were conducted to confirm the feasibility of the device concept and the proposed micro seismic sensor was fabricated by conventional MEMS technologies. Device characterization based on a vibration table recorded a linear relationship between applied velocities and output voltage amplitudes with a calculated sensitivity of 274V/(m/s) (20–80Hz). The performance of the proposed micro device was compared with a commercially available macro counterpart (MET2003), indicating strong correlations of these two types of devices in response to random vibrations while the proposed micro seismic sensor was capable of producing a lower power spectrum compared to MET2003. In summary, the electrochemical micro seismic sensor developed in this study is featured with mass fabrication capabilities due to MEMS technologies, comparable performance and lower power spectrum compared to conventional electrochemical seismometers. This newly developed micro sensor can be potentially used in the field of seismology, enabling the ground motion monitoring to locate earthquakes, volcanic eruptions, and other seismic sources.