Linjin Shi, Mengjiao Qu, Dongze Lv, Weiting Liu, Jin Xie
{"title":"A Two-channel Ultrasonic Flowmeter Based on AlN Piezoelectric Micromachined Ultrasonic Transducers Arrays with Improved Cross-correlation Method","authors":"Linjin Shi, Mengjiao Qu, Dongze Lv, Weiting Liu, Jin Xie","doi":"10.1088/1361-6439/ad0307","DOIUrl":"https://doi.org/10.1088/1361-6439/ad0307","url":null,"abstract":"Abstract This paper presents a highly accurate two-channel ultrasonic flowmeter based on AlN piezoelectric micromachined ultrasonic transducers (PMUTs) to measure flow rate in small-diameter pipes (9.6 mm). The ultrasonic transducers consist of four 10 by 10 PMUTs arrays with resonant frequency of 1 MHz in air. The ultrasonic transducers are excited by continuous sine voltage, and the transmitted and received signals are subjected to cross-correlation operation to obtain the time delay of the ultrasonic wave in the liquid. A dual-channel design of the flowmeter can reduce measurement errors by taking the average value. To reduce errors in the cross-correlation operation, an iterative algorithm is proposed, which effectively improves the measurement accuracy. The flowmeter is evaluated in flow range of 3.5–10 l min −1 , and has a small relative error of 0.7%.","PeriodicalId":16346,"journal":{"name":"Journal of Micromechanics and Microengineering","volume":"72 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135514436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Melinda A Lake-Speers, SINDHU PREETHAM BURUGUPALLY, David John Hoelzle
{"title":"Statics and dynamics of an underwater electrostatic curved electrode actuator with rough surfaces","authors":"Melinda A Lake-Speers, SINDHU PREETHAM BURUGUPALLY, David John Hoelzle","doi":"10.1088/1361-6439/acfa0b","DOIUrl":"https://doi.org/10.1088/1361-6439/acfa0b","url":null,"abstract":"Abstract Here, we present a model, design, static and dynamic testing, and analysis of an electrostatic curved electrode actuator in deionized water. The actuator is integrated within a microfluidic device designed for high throughput cell sorting. The actuator shifts the bifurcation point of a Y-shaped microfluidic channel to simultaneously increase the width of one channel while decreasing the width of another channel, thus changing the bias in hydrodynamic resistance between outlet channels. The actuator is modeled as a clamped-roller beam and the static displacement is calculated based on Rayleigh–Ritz energy methods. The model accounts for oxide growth and surface roughness that occurs during fabrication. We observe that modeling a rough contact surface improves the maximum displacement prediction to within less than 20% error from the experimental value. Additionally, the model predicts a release voltage within less than 8% error of the experimental value. We also present dynamic experiments to test the actuator displacement at frequencies from 1 to 4096 Hz and show that the actuator achieves large displacements ( <?CDATA $gt$?> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" overflow=\"scroll\"> <mml:mo>></mml:mo> </mml:math> 8 µ m) at high frequencies ( <?CDATA $gt$?> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" overflow=\"scroll\"> <mml:mo>></mml:mo> </mml:math> 100 Hz).","PeriodicalId":16346,"journal":{"name":"Journal of Micromechanics and Microengineering","volume":"53 70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135823308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Gaurav Anand, Samira Safaripour, Jaynie Tercovich, Jenna Capozzi, Mark Griffin, Nathan Schin, Nicholas Mirra, Craig Snoeyink
{"title":"A Simple Electrode Insulation and Channel Fabrication Technique for High-Electric Field Microfluidics","authors":"Gaurav Anand, Samira Safaripour, Jaynie Tercovich, Jenna Capozzi, Mark Griffin, Nathan Schin, Nicholas Mirra, Craig Snoeyink","doi":"10.1088/1361-6439/acffd5","DOIUrl":"https://doi.org/10.1088/1361-6439/acffd5","url":null,"abstract":"Abstract A simple and robust electrode insulation technique that can withstand a voltage as high as <?CDATA $mathrm{1000,V}$?> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" overflow=\"scroll\"> <mml:mrow> <mml:mn>1000</mml:mn> <mml:mi mathvariant=\"normal\">V</mml:mi> </mml:mrow> </mml:math> , which is equivalent to an electric field strength of <?CDATA ${sim}1$?> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" overflow=\"scroll\"> <mml:mrow> <mml:mo>∼</mml:mo> </mml:mrow> <mml:mn>1</mml:mn> </mml:math> MV m −1 across a <?CDATA $10,mumathrm{m}$?> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" overflow=\"scroll\"> <mml:mn>10</mml:mn> <mml:mi>μ</mml:mi> <mml:mrow> <mml:mi mathvariant=\"normal\">m</mml:mi> </mml:mrow> </mml:math> channel filled with an electrolyte of conductivity <?CDATA ${sim}0.1$?> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" overflow=\"scroll\"> <mml:mrow> <mml:mo>∼</mml:mo> </mml:mrow> <mml:mn>0.1</mml:mn> </mml:math> S m −1 , i.e. higher than sea water’s conductivity, is introduced. A multi-dielectric layers approach is adopted to fabricate the blocked electrodes, which helps reduce the number of material defects. Dielectric insulation with an exceptional breakdown electric field strength for an electrolyte confined between electrodes can have a wide range of applications in microfluidics, like high electric field strength-based dielectrophoresis. The voltage-current characteristics are studied for various concentrations of sodium chloride solution to estimate the insulation strength of the proposed materials, and the breakdown strength is calculated at the point where the electrical insulation failed. A detailed adhesion technique is also demonstrated, which will reduce the ambiguity around the fabrication of a sealed channel using SU-8.","PeriodicalId":16346,"journal":{"name":"Journal of Micromechanics and Microengineering","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136078074","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Review Paper: MEMS Audio Speakers","authors":"Meera Vikas Garud, Rudra Pratap","doi":"10.1088/1361-6439/acfe86","DOIUrl":"https://doi.org/10.1088/1361-6439/acfe86","url":null,"abstract":"Abstract Miniaturization of electro-mechanical sensors and actuators has benefited from an advancement in CMOS technology over the years. However, miniaturization of audio speakers has seen considerable development only in the recent times. This paper reviews the developments in MEMS audio speaker research and the initial commercial products available in the market. At first glance, it appears that the relatively slow development of MEMS speakers can be attributed to the fact that the principle of actuation has remained unchanged for several decades. Unfortunately, the physics behind audible sound production holds us back from exclusively adopting miniaturized speakers — sound pressure level is directly proportional to the area of the sound radiating surface. Nevertheless, researchers are continuing to explore new avenues for designing and developing MEMS speakers, without limiting themselves to the existing actuation principles. With newly discovered materials and improving technology, the research in MEMS speakers is gaining attention and new products are emerging. A speaker design based on piezoelectric actuation or electrostatics actuation is favourable at MEMS scale. Indian research community is also contributing to advances in MEMS speakers and near-ultrasonic devices. This paper reviews the development in MEMS audio speakers in India and in the world. The tabulated review findings aim to offer readers an overview of the development of micro-speakers and to provide guidance for designing new micro-speakers.","PeriodicalId":16346,"journal":{"name":"Journal of Micromechanics and Microengineering","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135193488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"MXene (Ti3C2Tx)/TMD (ReSe2) Nanohybrid-based Flexible Electromechanical Sensors for Cervical Collar Strain and Shoulder Load Detection Applications","authors":"Vivek Adepu, Manav Tathacharya, Raghuram CS, Parikshit Sahatiya","doi":"10.1088/1361-6439/acfc52","DOIUrl":"https://doi.org/10.1088/1361-6439/acfc52","url":null,"abstract":"Abstract The possibly complex impacts of volunteer’s heavy backpacks, chronic neck pain are significant concerns and must be considered by the scientific and academic community. However already existing several alert systems can tackle these issues, but the evaluation approaches are costly and complicated. In this regard, ReSe 2 /Ti 3 C 2 T x nanohybrid based flexible sensors were fabricated by low-cost vacuum filtration technique and integrated into cervical collar strain and shoulder load detection alert systems to tackle these issues. The fabricated sensor displayed an excellent gauge factor of 14.38 and an improved sensitivity of 14.06 kPa −1 . The response and recovery time of the pressure and strain sensor were 288 and 90 msec at 15% strain and 95 and 182 msec at 1.477 kPa pressure. There was a negligible degradation in performance when the pressure sensor was assessed for 5000 and the strain sensor for 4500 cycles, proving that the fabricated sensors are highly durable. The comprehensive underlying transduction mechanism is elucidated by intrinsic piezoresistive properties of nanohybrid (ReSe 2 /Ti 3 C 2 T x ) and Schottky barrier height mechanism with complete electronic bandstructure realization using real-time ultraviolet photoelectron spectroscopy. Also, to transfer/receive data wirelessly on an Android/ios based smartphone, the fabricated sensors were connected to an electrical circuit with a microcontroller and Bluetooth module. The effective corroboration of the ReSe 2 /Ti 3 C 2 T x nanohybrid based physical sensors initiates innovative prospects in the field of flexible electronics.","PeriodicalId":16346,"journal":{"name":"Journal of Micromechanics and Microengineering","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135131304","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ye Wang, Shengshun Duan, Jiachen Liu, Fangzhi Zhao, Pinzhen Chen, Qiongfeng Shi, Jun Wu
{"title":"Highly-sensitive expandable microsphere-based flexible pressure sensor for human-machine interaction","authors":"Ye Wang, Shengshun Duan, Jiachen Liu, Fangzhi Zhao, Pinzhen Chen, Qiongfeng Shi, Jun Wu","doi":"10.1088/1361-6439/acfdb5","DOIUrl":"https://doi.org/10.1088/1361-6439/acfdb5","url":null,"abstract":"Abstract Flexible microstructural pressure sensors (FMPSs) have been widely used in different areas including health monitoring, human-machine interaction and electronic skin for their good reliability, easy fabrication, and highly sensitive sensing performance. Although the use of a sensing layer with microstructure improves the sensor sensitivity, it also results in limited sensitive pressure range, slow response and poor cyclic stability, which prevents the sensors from being utilized in applications requiring wide detect range, real-time response and high durability. Here, we propose an advanced micro-structured sensing layer through doping thermally expandable microspheres (EP) into the screen-printing carbon black (CB) slurry to enhance its mechanical properties. An FMPS is then developed based on this enhanced micro-structured sensing layer. Benefiting from the expanded microsphere-like microstructure, the as-prepared sensor features high sensitivity (37.16 kPa-1), fast response/recovery time (126 / 52 ms), and good mechanical stability (over 3000 cycles). In addition, a home-made and effective collision avoidance system consisting of a robotic arm, the pressure sensor, a MEGA2560 microcontroller unit (MCU) and a computer is constructed to indicate the sensor’s outstanding tactile perception characteristic, making it a promising candidate for intelligent robotic applications such as human-robot collaboration (HRC). Furthermore, we develop a pressure sensor array and demonstrate its ability to spatial pressure distribution perception. The developed microsphere-based pressure sensor and its array show great potential to be adopted in various monitoring and interactive applications such as humanoid robots, smart home, human-machine interaction, etc.","PeriodicalId":16346,"journal":{"name":"Journal of Micromechanics and Microengineering","volume":"99 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135534350","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nianqiang Zhang, Jin Ji, Jilai Wang, Zhenyu Shi, Chengpeng Zhang
{"title":"Experimental and simulation investigation for imprinting and buckling of V-groove/wrinkles hierarchical array","authors":"Nianqiang Zhang, Jin Ji, Jilai Wang, Zhenyu Shi, Chengpeng Zhang","doi":"10.1088/1361-6439/acf93f","DOIUrl":"https://doi.org/10.1088/1361-6439/acf93f","url":null,"abstract":"Abstract With the in-depth development and continuous innovation of micro and nano manufacturing technology, flexible strain sensors are more and more widely used in various fields, including soft robots, smart clothing and so on, and high-performance sensors are more in demand. An efficient tactic for enhancing the performance of flexible strain sensors is to design and create hierarchical structures, and its efficient and controllable manufacturing is a key problem. The controllable manufacturing of V-groove/wrinkles hierarchical structure is realized by nano-imprint and prestretch-release process, which provides an effective method for large-area controllable preparation of hierarchical structure, and provides a foundation for the construction of high-performance flexible strain sensor. Single-factor experiments were carried out on the slope of the primary structure, pre-strain and substrate thickness, and response surface analysis was carried out by Box–Behnken experiments. The results of the structure’s formation are significantly influenced by the slope and substrate thickness, and the optimal process parameters are obtained by response surface analysis. Then the impact of each process parameter was investigated using a process simulation model. Finally, the forming conditions of hierarchical structure are analyzed. This study can provide guidance for the efficient and controllable manufacturing of micro/nano hierarchical structures.","PeriodicalId":16346,"journal":{"name":"Journal of Micromechanics and Microengineering","volume":"328 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134903936","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Development of Multi-depth Probing 3D Microelectrode Array to Record Electrophysiological Activity within Neural Cultures","authors":"Neeraj Yadav, Donatella Di Lisa, Flavio Giacomozzi, Alessandro Cian, Damiano Giubertoni, Sergio Martinoia, Leandro Lorenzelli","doi":"10.1088/1361-6439/acf940","DOIUrl":"https://doi.org/10.1088/1361-6439/acf940","url":null,"abstract":"Abstract Microelectrode arrays (MEAs) play a crucial role in investigating the electrophysiological activities of neuronal populations. Although two-dimensional neuronal cell cultures have predominated in neurophysiology in monitoring in-vitro the electrophysiological activity, recent research shifted toward culture using three-dimensional (3D) neuronal network structures for developing more sophisticated and realistic neuronal models. Nevertheless, many challenges remain in the electrophysiological analysis of 3D neuron cultures, among them the development of robust platforms for investigating the electrophysiological signal at multiple depths of the 3D neurons’ networks. While various 3D MEAs have been developed to probe specific depths within the layered nervous system, the fabrication of microelectrodes with different heights, capable of probing neural activity from the surface as well as from the different layers within the neural construct, remains challenging. This study presents a novel 3D MEA with microelectrodes of different heights, realized through a multi-stage mold-assisted electrodeposition process. Our pioneering platform allows meticulous control over the height of individual microelectrodes as well as the array topology, paving the way for the fabrication of 3D MEAs consisting of electrodes with multiple heights that could be tailored for specific applications and experiments. The device performance was characterized by measuring electrochemical impedance, and noise, and capturing spontaneous electrophysiological activity from neurospheroids derived from human induced pluripotent stem cells. These evaluations unequivocally validated the significant potential of our innovative multi-height 3D MEA as an avant-garde platform for in vitro 3D neuronal studies.","PeriodicalId":16346,"journal":{"name":"Journal of Micromechanics and Microengineering","volume":"41 9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136011678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kangning Zhang, Xinyu Wu, Dazuo Wang, Xinyuan Hua, Ze Zhang, Peng Li, Bing Tian, Hairong Wang, Jianhai Sun
{"title":"Micro gas chromatography column coated with ionic liquid/metal-organic framework composites as the stationary phase","authors":"Kangning Zhang, Xinyu Wu, Dazuo Wang, Xinyuan Hua, Ze Zhang, Peng Li, Bing Tian, Hairong Wang, Jianhai Sun","doi":"10.1088/1361-6439/acf93e","DOIUrl":"https://doi.org/10.1088/1361-6439/acf93e","url":null,"abstract":"Abstract In this paper, the μ GC-IL/MOF and the μ GC-IL were prepared using [P66614][NTf 2 ]/ZIF-8 and [P66614][NTf 2 ] as the stationary phase, respectively. [P66614][NTf 2 ]/ZIF-8 composite stationary phase material has high specific surface area and porous structure, which increases the diffusion of gas molecules in the column. Compared to μ GC-IL, μ GC-IL/MOF can separate n-alkanes mixture (C5–C12) and lung cancer biomarkers (pentane, isoprene, acetone, benzene, 2-pentanone) with higher resolution, and the resolution ( R ) of pentane and isoprene was increased by 257.00% in particular. The μ GC-IL/MOF can separate lung cancer biomarkers in about 5 min with optimal carrier gas velocity and column temperature. The retention times of pentane, isoprene, acetone, benzene, and 2-pentanone were 0.884 min, 1.246 min, 1.634 min, 2.204 min, and 3.049 min, respectively. The resolutions of adjacent peaks were 1.785, 1.525, 2.521, and 3.514, respectively. Which meets the requirements of quantitative analysis ( R > 1.5). Therefore, the μ GC-IL/MOF is expected to be integrated into portable devices for environmental monitoring and medical diagnosis in the future.","PeriodicalId":16346,"journal":{"name":"Journal of Micromechanics and Microengineering","volume":"80 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136011680","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R Scott Downen, Quan Dong, Julius Lee Chen, Zhenyu Li
{"title":"Design and fabrication of a low-cost microfluidic cartridge with integrated pressure-driven check valve for molecular diagnostics platforms","authors":"R Scott Downen, Quan Dong, Julius Lee Chen, Zhenyu Li","doi":"10.1088/1361-6439/acf8d2","DOIUrl":"https://doi.org/10.1088/1361-6439/acf8d2","url":null,"abstract":"Abstract This paper describes the design, fabrication, and preliminary testing of a low-cost, easy to manufacture microfluidics cartridge capable of fluid storage and manipulation through a custom pressure-driven check valve. Cartridge components are fabricated using a desktop CNC and laser cutter, the check valve is fabricated using PDMS in a custom acrylic mold, and the components are assembled using a thermal diffusion welder. Following assembly, preliminary testing of the cartridge, including fluid manipulation and use for molecular diagnostics, was performed. To pull a sample into the lysing chamber, a vacuum over 1.4PSI was required. No opening of the valve to the reaction chamber was observed. Moving fluid across the custom valve from the lysing chamber to the reaction chamber then required a vacuum over 4.5PSI. Finally, a proof-of-concept demonstration of one potential application was performed using a custom benchtop LAMP system for molecular diagnostic testing. The low-cost nature of the design, ease of manufacturing, fluid storage and manipulation demonstrated make this design ideal for research and high-volume testing in low resource environments.","PeriodicalId":16346,"journal":{"name":"Journal of Micromechanics and Microengineering","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136060368","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}