Abstract. We designed a low-cost expandable current profiler including software and hardware. An expendable current profiler (XCP) is an observation instrument that rapidly measures currents based on the principle that currents cut the geomagnetic field to induce electric fields. It is important to reduce the cost of an XCP because it is a single-use device. The digitization of the previously developed XCP is carried out underwater, which requires the probe to contain not only analogue circuits for acquiring signals but also digital circuits and digital chips, which are relatively expensive. In this study, an XCP has been developed that adopts signal modulation and demodulation to transmit analogue signals on an enamelled wire, and the signal digitization occurs above the surface of the water. The cost of the instrument is effectively reduced by half while maintaining the ability to measure parameters such as sea current and temperature in real-time. After comparison with data processed from laboratory tests, the acquisition circuit showed accuracy within one-thousandth of one per cent, and the XCP analogue circuit developed for the overall system was stable and reliable. The system exhibited an acquisition accuracy higher than 50 nV for 16 Hz, and the quality of the acquired signal met the requirements for an XCP instrument.
{"title":"Development of an Expendable Current Profiler Based on Modulation and Demodulation","authors":"Keyu Zhou, Qisheng Zhang, Guangyuan Chen, Zucan Lin, Yunliang Liu, Pengyu Li","doi":"10.5194/gi-2022-22","DOIUrl":"https://doi.org/10.5194/gi-2022-22","url":null,"abstract":"<strong>Abstract.</strong> We designed a low-cost expandable current profiler including software and hardware. An expendable current profiler (XCP) is an observation instrument that rapidly measures currents based on the principle that currents cut the geomagnetic field to induce electric fields. It is important to reduce the cost of an XCP because it is a single-use device. The digitization of the previously developed XCP is carried out underwater, which requires the probe to contain not only analogue circuits for acquiring signals but also digital circuits and digital chips, which are relatively expensive. In this study, an XCP has been developed that adopts signal modulation and demodulation to transmit analogue signals on an enamelled wire, and the signal digitization occurs above the surface of the water. The cost of the instrument is effectively reduced by half while maintaining the ability to measure parameters such as sea current and temperature in real-time. After comparison with data processed from laboratory tests, the acquisition circuit showed accuracy within one-thousandth of one per cent, and the XCP analogue circuit developed for the overall system was stable and reliable. The system exhibited an acquisition accuracy higher than 50 nV for 16 Hz, and the quality of the acquired signal met the requirements for an XCP instrument.","PeriodicalId":48742,"journal":{"name":"Geoscientific Instrumentation Methods and Data Systems","volume":"55 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2022-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138538563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Brady P. Strabel, L. Regoli, M. Moldwin, L. Ojeda, Yining Shi, J. Thoma, Isaac Narrett, Bret Bronner, Matthew Pellioni
Abstract. The design, characteristics, and performance of a CubeSat magnetometer board (Quad-Mag) equipped with four PNI RM3100 magnetometers is presented. The low size, weight, power, and cost of the RM3100 enables the inclusion of four sensors on a single board, allowing a potential factor of 2 reduction in the noise floor established for an individual sensor via oversampling with multiple sensors. The instrument experimentally achieved a noise floor of 5.34 nT (individual axis), averaging across each axis of the four magnetometers, at a 65 Hz sampling rate. This approaches the theoretically established limit for the system of 4.37 nT at 40 Hz. A single onboard Texas Instrument MSP430 microcontroller handles synchronization of the magnetometers and facilitates data collection through a simple UART-based command interface to a host system. The Quad-Mag system has a mass of 59.05 g and total power consumption of 23 mW while sampling and 14 mW while idle. The Quad-Mag enables nearly 1 nT magnetic field measurements at 1 Hz using commercial off-the-shelf sensors for space applications under optimal conditions.
{"title":"Quad-Mag board for CubeSat applications","authors":"Brady P. Strabel, L. Regoli, M. Moldwin, L. Ojeda, Yining Shi, J. Thoma, Isaac Narrett, Bret Bronner, Matthew Pellioni","doi":"10.5194/gi-11-375-2022","DOIUrl":"https://doi.org/10.5194/gi-11-375-2022","url":null,"abstract":"Abstract. The design, characteristics, and performance of a CubeSat magnetometer board (Quad-Mag) equipped with four PNI RM3100 magnetometers is presented. The low size, weight, power, and cost of the RM3100 enables the inclusion of four sensors on a single board, allowing a potential factor of 2 reduction in the noise floor established for an individual sensor via oversampling with multiple sensors. The instrument experimentally achieved a noise floor of 5.34 nT (individual axis), averaging across each axis of the four magnetometers, at a 65 Hz sampling rate. This approaches the theoretically established limit for the system of 4.37 nT at 40 Hz. A single onboard Texas Instrument MSP430 microcontroller handles synchronization of the magnetometers and facilitates data collection through a simple UART-based command interface to a host system. The Quad-Mag system has a mass of 59.05 g and total power consumption of 23 mW while sampling and 14 mW while idle. The Quad-Mag enables nearly 1 nT magnetic field measurements at 1 Hz using commercial off-the-shelf sensors for space applications under optimal conditions.\u0000","PeriodicalId":48742,"journal":{"name":"Geoscientific Instrumentation Methods and Data Systems","volume":" ","pages":""},"PeriodicalIF":1.8,"publicationDate":"2022-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42960954","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Stefano Gianessi, Matteo Polo, Luca Stevanato, Marcello Lunardon, Till Francke, Sascha Oswald, Hami Ahmed, Arsenio Tolosa, Georg Welting, Gerd Dercon, Emil Fulajtar, Lee Heng, Gabriele Baroni
Abstract. Cosmic-ray neutron sensing (CRNS) has emerged as a reliable method for soil moisture and snow estimation. However, the applicability of this method beyond research has been limited due to, among others, the use of relatively large and expensive sensors. This paper presents the tests conducted to a new scintillator-based sensor especially designed to jointly measure neutron counts, total gamma-rays, and muons. The neutron signal is firstly compared against two conventional gas-tube-based CRNS sensors at two locations (Austria and Germany). The estimated soil moisture is further assessed at four agricultural sites in Italy based on gravimetric soil moisture collected within the sensor footprint. The results show that the signal detected by the new scintillator-based CRNS sensor is well in agreement with the conventional CRNS sensors and with the gravimetric soil moisture measurements. In addition, the muons and the total gamma-rays simultaneously detected by the sensor show promising features for a better correction of the incoming variability and for discriminating irrigation and precipitation events, respectively. Further experiments and analyses should be conducted, however, to better understand the added value of these additional data for soil moisture estimation. Overall, the new scintillator design shows to be a valid and compact alternative to conventional CRNS sensors for non-invasive soil moisture monitoring that can open the path to a wide range of applications.
{"title":"Testing a novel sensor design to jointly measure cosmic-ray neutrons, muons and gamma rays for non-invasive soil moisture estimation","authors":"Stefano Gianessi, Matteo Polo, Luca Stevanato, Marcello Lunardon, Till Francke, Sascha Oswald, Hami Ahmed, Arsenio Tolosa, Georg Welting, Gerd Dercon, Emil Fulajtar, Lee Heng, Gabriele Baroni","doi":"10.5194/gi-2022-20","DOIUrl":"https://doi.org/10.5194/gi-2022-20","url":null,"abstract":"<strong>Abstract.</strong> Cosmic-ray neutron sensing (CRNS) has emerged as a reliable method for soil moisture and snow estimation. However, the applicability of this method beyond research has been limited due to, among others, the use of relatively large and expensive sensors. This paper presents the tests conducted to a new scintillator-based sensor especially designed to jointly measure neutron counts, total gamma-rays, and muons. The neutron signal is firstly compared against two conventional gas-tube-based CRNS sensors at two locations (Austria and Germany). The estimated soil moisture is further assessed at four agricultural sites in Italy based on gravimetric soil moisture collected within the sensor footprint. The results show that the signal detected by the new scintillator-based CRNS sensor is well in agreement with the conventional CRNS sensors and with the gravimetric soil moisture measurements. In addition, the muons and the total gamma-rays simultaneously detected by the sensor show promising features for a better correction of the incoming variability and for discriminating irrigation and precipitation events, respectively. Further experiments and analyses should be conducted, however, to better understand the added value of these additional data for soil moisture estimation. Overall, the new scintillator design shows to be a valid and compact alternative to conventional CRNS sensors for non-invasive soil moisture monitoring that can open the path to a wide range of applications.","PeriodicalId":48742,"journal":{"name":"Geoscientific Instrumentation Methods and Data Systems","volume":"4 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138538542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Thermohaline staircases are stepped structures of alternating thick mixed layers and thin high-gradient interfaces. These structures can be up to several tens of metres thick and are associated with double-diffusive mixing. Thermohaline staircases occur across broad swathes of the Arctic and tropical and subtropical oceans and can increase rates of diapycnal mixing by up to 5 times the background rate, driving substantial nutrient fluxes to the upper ocean. In this study, we present an improved classification algorithm to detect thermohaline staircases in ocean glider profiles. We use a dataset of 1162 glider profiles from the tropical North Atlantic collected in early 2020 at the edge of a known thermohaline staircase region. The algorithm identifies thermohaline staircases in 97.7 % of profiles that extend deeper than 300 m. We validate our algorithm against previous results obtained from algorithmic classification of Argo float profiles. Using fine-resolution temperature data from a fast-response thermistor on one of the gliders, we explore the effect of varying vertical bin sizes on detected thermohaline staircases. Our algorithm builds on previous work by adding improved flexibility and the ability to classify staircases from profiles with noisy salinity data. Using our results, we propose that the incidence of thermohaline staircases is limited by strong background vertical gradients in conservative temperature and absolute salinity.
{"title":"Glider observations of thermohaline staircases in the tropical North Atlantic using an automated classifier","authors":"Callum Rollo, Karen J. Heywood, Rob A. Hall","doi":"10.5194/gi-11-359-2022","DOIUrl":"https://doi.org/10.5194/gi-11-359-2022","url":null,"abstract":"Thermohaline staircases are stepped structures of alternating thick mixed layers and thin high-gradient interfaces. These structures can be up to several tens of metres thick and are associated with double-diffusive mixing. Thermohaline staircases occur across broad swathes of the Arctic and tropical and subtropical oceans and can increase rates of diapycnal mixing by up to 5 times the background rate, driving substantial nutrient fluxes to the upper ocean. In this study, we present an improved classification algorithm to detect thermohaline staircases in ocean glider profiles. We use a dataset of 1162 glider profiles from the tropical North Atlantic collected in early 2020 at the edge of a known thermohaline staircase region. The algorithm identifies thermohaline staircases in 97.7 % of profiles that extend deeper than 300 m. We validate our algorithm against previous results obtained from algorithmic classification of Argo float profiles. Using fine-resolution temperature data from a fast-response thermistor on one of the gliders, we explore the effect of varying vertical bin sizes on detected thermohaline staircases. Our algorithm builds on previous work by adding improved flexibility and the ability to classify staircases from profiles with noisy salinity data. Using our results, we propose that the incidence of thermohaline staircases is limited by strong background vertical gradients in conservative temperature and absolute salinity.","PeriodicalId":48742,"journal":{"name":"Geoscientific Instrumentation Methods and Data Systems","volume":"93 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2022-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138538540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xinhua Zhou, Tian Gao, Ning Zheng, Bai Yang, Yanlei Li, Fengyuan Yu, Tala Awada, Jiaojun Zhu
Ecosystem CO<span><sub>2</sub></span>–H<span><sub>2</sub></span>O data measured by infrared gas analyzers in open-path eddy-covariance (OPEC) systems have numerous applications, such as estimations of CO<span><sub>2</sub></span> and H<span><sub>2</sub></span>O fluxes in the atmospheric boundary layer. To assess the applicability of the data for these estimations, data uncertainties from analyzer measurements are needed. The uncertainties are sourced from the analyzers in zero drift, gain drift, cross-sensitivity, and precision variability. These four uncertainty sources are individually specified for analyzer performance, but so far no methodology exists yet to combine these individual sources into a composite uncertainty for the specification of an overall accuracy, which is ultimately needed. Using the methodology for closed-path eddy-covariance systems, this overall accuracy for OPEC systems is determined from all individual uncertainties via an accuracy model and further formulated into CO<span><sub>2</sub></span> and H<span><sub>2</sub></span>O accuracy equations. Based on atmospheric physics and the biological environment, for EC150 infrared CO<span><sub>2</sub></span>–H<span><sub>2</sub></span>O analyzers, these equations are used to evaluate CO<span><sub>2</sub></span> accuracy (<span>±1.22</span> mgCO<span><sub>2</sub></span> m<span><sup>−3</sup></span>, relatively <span>±0.19</span> %) and H<span><sub>2</sub></span>O accuracy (<span>±0.10</span> gH<span><sub>2</sub></span>O m<span><sup>−3</sup></span>, relatively <span>±0.18</span> % in saturated air at 35 <span><sup>∘</sup></span>C and 101.325 kPa). Both accuracies are applied to conceptual models addressing their roles in uncertainty analyses for CO<span><sub>2</sub></span> and H<span><sub>2</sub></span>O fluxes. For the high-frequency air temperature derived from H<span><sub>2</sub></span>O density along with sonic temperature and atmospheric pressure, the role of H<span><sub>2</sub></span>O accuracy in its uncertainty is similarly addressed. Among the four uncertainty sources, cross-sensitivity and precision variability are minor, although unavoidable, uncertainties, whereas zero drift and gain drift are major uncertainties but are minimizable via corresponding zero and span procedures during field maintenance. The accuracy equations provide rationales to assess and guide the procedures. For the atmospheric background CO<span><sub>2</sub></span> concentration, CO<span><sub>2</sub></span> zero and CO<span><sub>2</sub></span> span procedures can narrow the CO<span><sub>2</sub></span> accuracy range by 40 %, from <span>±1.22</span> to <span>±0.72</span> mgCO<span><sub>2</sub></span> m<span><sup>−3</sup></span>. In hot and humid weather, H<span><sub>2</sub></span>O gain drift potentially adds more to the H<span><sub>2</sub></span>O measurement uncertainty, which requires more attention. If H<span><sub>2</sub></span>O zero and H<span><sub>2</sub></span>O span procedures can be performed
开放路径涡旋协方差(OPEC)系统中红外气体分析仪测量的生态系统CO2 - H2O数据有许多应用，例如大气边界层中CO2和H2O通量的估计。为了评估这些估计的数据的适用性，需要从分析仪测量的数据不确定度。不确定性来自于分析仪的零漂移、增益漂移、交叉灵敏度和精度变异性。这四个不确定度源是为分析仪性能单独指定的，但到目前为止还没有方法将这些单独的不确定度源组合成一个综合的不确定度，以规范总体精度，这是最终需要的。使用封闭路径涡流协方差系统的方法，欧佩克系统的总体精度通过精度模型从所有个体不确定性中确定，并进一步制定为二氧化碳和h2o精度方程。基于大气物理和生物环境，对EC150红外CO2 - H2O分析仪，使用这些方程来评估CO2精度(±1.22 mgCO2 m - 3，相对±0.19%)和H2O精度(±0.10 gH2O m - 3，相对±0.18%，在35°C和101.325 kPa的饱和空气中)。这两种精度都适用于概念模型，解决了它们在CO2和h2o通量不确定性分析中的作用。对于由H2O密度、声波温度和大气压力导出的高频空气温度，H2O精度在其不确定性中的作用也同样得到了解决。在四个不确定性来源中，交叉灵敏度和精度变化是次要的，虽然不可避免，不确定性，而零漂移和增益漂移是主要的不确定性，但在现场维护期间通过相应的零和跨度程序可以最小化。准确度方程为评估和指导程序提供了依据。对于大气背景CO2浓度，CO2零和CO2跨度程序可以将CO2精度范围缩小40%，从±1.22到±0.72 mgCO2 m - 3。在炎热潮湿的天气中，H2Ogain漂移可能会增加H2O测量的不确定度，需要引起更多的注意。如果能在5到35°C范围内实际进行H2O零点和H2O跨度测量，H2O精度至少可以提高30%:从±0.10到±0.07 gH2O m - 3。在冻结条件下，水跨度过程是不切实际的，但可以忽略，因为它对总体不确定性的贡献微不足道。然而，在这些条件下，H2O和CO2的零程序作为一种操作和有效的选择是必要的，以最大限度地减少H2O测量的不确定性。
{"title":"Accuracies of field CO2–H2O data from open-path eddy-covariance flux systems: assessment based on atmospheric physics and biological environment","authors":"Xinhua Zhou, Tian Gao, Ning Zheng, Bai Yang, Yanlei Li, Fengyuan Yu, Tala Awada, Jiaojun Zhu","doi":"10.5194/gi-11-335-2022","DOIUrl":"https://doi.org/10.5194/gi-11-335-2022","url":null,"abstract":"Ecosystem CO<span><sub>2</sub></span>–H<span><sub>2</sub></span>O data measured by infrared\u0000gas analyzers in open-path eddy-covariance (OPEC) systems have numerous\u0000applications, such as estimations of CO<span><sub>2</sub></span> and H<span><sub>2</sub></span>O fluxes in the\u0000atmospheric boundary layer. To assess the applicability of the data for\u0000these estimations, data uncertainties from analyzer measurements are needed.\u0000The uncertainties are sourced from the analyzers in zero drift, gain drift,\u0000cross-sensitivity, and precision variability. These four uncertainty sources\u0000are individually specified for analyzer performance, but so far no methodology\u0000exists yet to combine these individual sources into a composite uncertainty\u0000for the specification of an overall accuracy, which is ultimately needed.\u0000Using the methodology for closed-path eddy-covariance systems, this overall\u0000accuracy for OPEC systems is determined from all individual uncertainties\u0000via an accuracy model and further formulated into CO<span><sub>2</sub></span> and H<span><sub>2</sub></span>O\u0000accuracy equations. Based on atmospheric physics and the biological\u0000environment, for EC150 infrared CO<span><sub>2</sub></span>–H<span><sub>2</sub></span>O analyzers, these\u0000equations are used to evaluate CO<span><sub>2</sub></span> accuracy (<span>±1.22</span> mgCO<span><sub>2</sub></span> m<span><sup>−3</sup></span>, relatively <span>±0.19</span> %) and H<span><sub>2</sub></span>O accuracy (<span>±0.10</span> gH<span><sub>2</sub></span>O m<span><sup>−3</sup></span>, relatively <span>±0.18</span> % in saturated air at 35 <span><sup>∘</sup></span>C and 101.325 kPa). Both accuracies are applied to conceptual\u0000models addressing their roles in uncertainty analyses for CO<span><sub>2</sub></span> and\u0000H<span><sub>2</sub></span>O fluxes. For the high-frequency air temperature derived from\u0000H<span><sub>2</sub></span>O density along with sonic temperature and atmospheric pressure, the\u0000role of H<span><sub>2</sub></span>O accuracy in its uncertainty is similarly addressed. Among\u0000the four uncertainty sources, cross-sensitivity and precision variability\u0000are minor, although unavoidable, uncertainties, whereas zero drift and gain\u0000drift are major uncertainties but are minimizable via corresponding zero and\u0000span procedures during field maintenance. The accuracy equations provide\u0000rationales to assess and guide the procedures. For the atmospheric\u0000background CO<span><sub>2</sub></span> concentration, CO<span><sub>2</sub></span> zero and CO<span><sub>2</sub></span> span\u0000procedures can narrow the CO<span><sub>2</sub></span> accuracy range by 40 %, from <span>±1.22</span> to <span>±0.72</span> mgCO<span><sub>2</sub></span> m<span><sup>−3</sup></span>. In hot and humid weather, H<span><sub>2</sub></span>O\u0000gain drift potentially adds more to the H<span><sub>2</sub></span>O measurement uncertainty,\u0000which requires more attention. If H<span><sub>2</sub></span>O zero and H<span><sub>2</sub></span>O span procedures\u0000can be performed ","PeriodicalId":48742,"journal":{"name":"Geoscientific Instrumentation Methods and Data Systems","volume":"21 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2022-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138538543","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-06DOI: 10.5194/egusphere-2022-1004
Shae McLafferty, Haley Bix, Kyle Bogatz, Jacqueline E. Reber
Abstract. Multiphase deformation, where a solid and fluid phase deform simultaneously, play a crucial role in a variety of geological hazards, such as landslides, glacial slip, and the transition from earthquakes to slow slip. In all these examples a continuous, viscous or fluid-like phase is mixed with a granular or brittle phase where both phases deform simultaneously when stressed. Understanding the interaction between the phases and how they will impact deformation dynamics is essential to improve hazard assessments for a wide variety of geo-hazards. Here, we present the design and first experimental results from a ring shear deformation apparatus capable of deforming multiple phases simultaneously. The experimental design allows for three dimensional observations during deformation in addition to unlimited shear strain, controllable normal force, and a variety of boundary conditions. To impose shear deformation, either the experimental chamber or lid rotate around its central axis while the other remains stationary. Normal and pulling force data are collected with force gauges located on the lid of the apparatus and between the pulling motor and the experimental chamber. Experimental materials are chosen to match the light refraction index of the experimental chamber, such that 3D observations can be made throughout the experiment with the help of a laser light sheet. We present experimental results where we deform hydropolymer orbs and cubes (brittle phase) and Carbopol® hydropolymer gel (fluid phase). Preliminary results show variability in force measurements and deformation styles between solid and fluid end member experiments. The ratio of solids to fluids and their relative competencies in multiphase experiments control deformation dynamics, which range from stick-slip to creep. The presented experimental strategy has the potential to shed light on multi-phase processes associated with multiple geo-hazards.
{"title":"New ring shear deformation apparatus for three-dimensional multiphase experiments: First results","authors":"Shae McLafferty, Haley Bix, Kyle Bogatz, Jacqueline E. Reber","doi":"10.5194/egusphere-2022-1004","DOIUrl":"https://doi.org/10.5194/egusphere-2022-1004","url":null,"abstract":"<strong>Abstract.</strong> Multiphase deformation, where a solid and fluid phase deform simultaneously, play a crucial role in a variety of geological hazards, such as landslides, glacial slip, and the transition from earthquakes to slow slip. In all these examples a continuous, viscous or fluid-like phase is mixed with a granular or brittle phase where both phases deform simultaneously when stressed. Understanding the interaction between the phases and how they will impact deformation dynamics is essential to improve hazard assessments for a wide variety of geo-hazards. Here, we present the design and first experimental results from a ring shear deformation apparatus capable of deforming multiple phases simultaneously. The experimental design allows for three dimensional observations during deformation in addition to unlimited shear strain, controllable normal force, and a variety of boundary conditions. To impose shear deformation, either the experimental chamber or lid rotate around its central axis while the other remains stationary. Normal and pulling force data are collected with force gauges located on the lid of the apparatus and between the pulling motor and the experimental chamber. Experimental materials are chosen to match the light refraction index of the experimental chamber, such that 3D observations can be made throughout the experiment with the help of a laser light sheet. We present experimental results where we deform hydropolymer orbs and cubes (brittle phase) and Carbopol® hydropolymer gel (fluid phase). Preliminary results show variability in force measurements and deformation styles between solid and fluid end member experiments. The ratio of solids to fluids and their relative competencies in multiphase experiments control deformation dynamics, which range from stick-slip to creep. The presented experimental strategy has the potential to shed light on multi-phase processes associated with multiple geo-hazards.","PeriodicalId":48742,"journal":{"name":"Geoscientific Instrumentation Methods and Data Systems","volume":"51 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2022-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138538553","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
William Colgan, Christopher Shields, Paval Talalay, Xiaopeng Fan, Austin P. Lines, Joshua Elliott, Harihar Rajaram, Kenneth Mankoff, Morten Jensen, Mira Backes, Yunchen Liu, Xianzhe Wei, Nanna B. Karlsson, Henrik Spanggård, Allan Ø. Pedersen
Abstract. We introduce the design and performance of a melt-tip ice-drilling system designed to insert a temperature sensor cable into ice. The melt tip is relatively simple and low cost, designed for a one-way trip to the ice-bed interface. The drilling system consists of a melt tip, umbilical cable, winch, interface, power supply, and support items. The melt tip and the winch are the most novel elements of the drilling system, and we make the hardware and electrical designs of these components available open access. Tests conducted in a laboratory ice well indicate that the melt tip has an electrical energy to forward melting heat transfer efficiency of ~35 % with a theoretical maximum penetration rate of ~12 m/hr at maximum 6.0 kW power. In contrast, ice-sheet testing suggests the melt tip has an analogous heat transfer efficiency of ~15 % with a theoretical maximum penetration rate of ~6 m/hr. We expect the efficiency gap between laboratory and field performance to decrease with increasing operator experience. Umbilical freeze-in due to borehole refreezing is the primary depth-limiting factor of the drilling system. Enthalpy-based borehole refreezing assessments predict refreezing below critical umbilical diameter in ~4 hours at -20 ˚C ice temperatures and ~20 hours at -2 ˚C. This corresponds to a theoretical depth limit of up to ~200 m, depending on firn thickness, ice temperature and operator experience.
{"title":"Design and Performance of the Hotrod Melt-Tip Ice-Drilling System","authors":"William Colgan, Christopher Shields, Paval Talalay, Xiaopeng Fan, Austin P. Lines, Joshua Elliott, Harihar Rajaram, Kenneth Mankoff, Morten Jensen, Mira Backes, Yunchen Liu, Xianzhe Wei, Nanna B. Karlsson, Henrik Spanggård, Allan Ø. Pedersen","doi":"10.5194/gi-2022-18","DOIUrl":"https://doi.org/10.5194/gi-2022-18","url":null,"abstract":"<strong>Abstract.</strong> We introduce the design and performance of a melt-tip ice-drilling system designed to insert a temperature sensor cable into ice. The melt tip is relatively simple and low cost, designed for a one-way trip to the ice-bed interface. The drilling system consists of a melt tip, umbilical cable, winch, interface, power supply, and support items. The melt tip and the winch are the most novel elements of the drilling system, and we make the hardware and electrical designs of these components available open access. Tests conducted in a laboratory ice well indicate that the melt tip has an electrical energy to forward melting heat transfer efficiency of ~35 % with a theoretical maximum penetration rate of ~12 m/hr at maximum 6.0 kW power. In contrast, ice-sheet testing suggests the melt tip has an analogous heat transfer efficiency of ~15 % with a theoretical maximum penetration rate of ~6 m/hr. We expect the efficiency gap between laboratory and field performance to decrease with increasing operator experience. Umbilical freeze-in due to borehole refreezing is the primary depth-limiting factor of the drilling system. Enthalpy-based borehole refreezing assessments predict refreezing below critical umbilical diameter in ~4 hours at -20 ˚C ice temperatures and ~20 hours at -2 ˚C. This corresponds to a theoretical depth limit of up to ~200 m, depending on firn thickness, ice temperature and operator experience.","PeriodicalId":48742,"journal":{"name":"Geoscientific Instrumentation Methods and Data Systems","volume":"17 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2022-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138538541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Robert M. Broadfoot, D. Miles, Warren Holley, A. Howarth
Abstract. CASSIOPE/e-POP, now known as Swarm-Echo, was launched in 2013 to study polar plasma outflow, neutral escape, and the effects of auroral currents on radio propagation in the ionosphere. The e-POP suite contains an array of eight instruments, including two fluxgate magnetometers on a shared boom. Until now, the two magnetometers relied on a set of preflight calibrations, which limited the accuracy of the magnetic field product and the magnetometers' utility for some applications. Here we present the results of an in situ calibration performed on data from 3 January 2014 to 30 January 2021 and a case study showing the improvements the calibration has made to the data utility. Periodic vector–vector calibration using the CHAOS magnetic field model results achieves an estimated root-mean-square (rms) uncertainty of 9 nT during nominal operation. This data product is now openly available through the ESA Swarm repository.
{"title":"In situ calibration of the Swarm-Echo magnetometers","authors":"Robert M. Broadfoot, D. Miles, Warren Holley, A. Howarth","doi":"10.5194/gi-11-323-2022","DOIUrl":"https://doi.org/10.5194/gi-11-323-2022","url":null,"abstract":"Abstract. CASSIOPE/e-POP, now known as Swarm-Echo, was launched in 2013 to study polar\u0000plasma outflow, neutral escape, and the effects of auroral currents on radio\u0000propagation in the ionosphere. The e-POP suite contains an array of eight\u0000instruments, including two fluxgate magnetometers on a shared boom. Until\u0000now, the two magnetometers relied on a set of preflight calibrations, which\u0000limited the accuracy of the magnetic field product and the magnetometers' utility for\u0000some applications. Here we present the results of an in situ calibration\u0000performed on data from 3 January 2014 to 30 January 2021 and a case\u0000study showing the improvements the calibration has made to the data utility.\u0000Periodic vector–vector calibration using the CHAOS magnetic field model\u0000results achieves an estimated root-mean-square (rms) uncertainty of 9 nT during nominal\u0000operation. This data product is now openly available through the ESA Swarm\u0000repository.","PeriodicalId":48742,"journal":{"name":"Geoscientific Instrumentation Methods and Data Systems","volume":" ","pages":""},"PeriodicalIF":1.8,"publicationDate":"2022-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47021604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Greene, C. Hansen, B. Narod, R. Dvorský, D. Miles
Abstract. Accurate high-precision magnetic field measurements are a significant challenge for many applications, including constellation missions studying space plasmas. Instrument stability and orthogonality are essential to enable meaningful comparison between disparate satellites in a constellation without extensive cross-calibration efforts. Here we describe the design and characterization of Tesseract – a fluxgate magnetometer sensor designed for low-noise, high-stability constellation applications. Tesseract's design takes advantage of recent developments in the manufacturing of custom low-noise fluxgate cores. Six of these custom racetrack fluxgate cores are securely and compactly mounted within a single solid three-axis symmetric base. Tesseract's feedback windings are configured as a four-square Merritt coil to create a large homogenous magnetic null inside the sensor where the fluxgate cores are held in a near-zero field, regardless of the ambient magnetic field, to improve the reliability of the core magnetization cycle. A Biot–Savart simulation is used to optimize the homogeneity of the field generated by the feedback Merritt coils and was verified experimentally to be homogeneous within 0.42 % along the racetrack cores' axes. The thermal stability of the sensor's feedback windings is measured using an insulated container filled with dry ice inside a coil system. The sensitivity over temperature of the feedback windings is found to be between 13 and 17 ppm ∘C−1. The sensor's three axes maintain orthogonality to within at most 0.015∘ over a temperature range of −45 to 20 ∘C. Tesseract's cores achieve a magnetic noise floor of 5 pT √Hz−1 at 1 Hz. Tesseract will be flight demonstrated on the ACES-II sounding rockets, currently scheduled to launch in late 2022 and again aboard the TRACERS satellite mission as part of the MAGIC technology demonstration which is currently scheduled to launch in 2023.
{"title":"Tesseract – a high-stability, low-noise fluxgate sensor designed for constellation applications","authors":"K. Greene, C. Hansen, B. Narod, R. Dvorský, D. Miles","doi":"10.5194/gi-11-307-2022","DOIUrl":"https://doi.org/10.5194/gi-11-307-2022","url":null,"abstract":"Abstract. Accurate high-precision magnetic field measurements are a\u0000significant challenge for many applications, including constellation missions studying space plasmas. Instrument stability and orthogonality are essential\u0000to enable meaningful comparison between disparate satellites in a\u0000constellation without extensive cross-calibration efforts. Here we describe\u0000the design and characterization of Tesseract – a fluxgate magnetometer\u0000sensor designed for low-noise, high-stability constellation applications.\u0000Tesseract's design takes advantage of recent developments in the\u0000manufacturing of custom low-noise fluxgate cores. Six of these custom racetrack fluxgate cores are securely and compactly mounted within a single\u0000solid three-axis symmetric base. Tesseract's feedback windings are\u0000configured as a four-square Merritt coil to create a large homogenous\u0000magnetic null inside the sensor where the fluxgate cores are held in a near-zero field, regardless of the ambient magnetic field, to improve the\u0000reliability of the core magnetization cycle. A Biot–Savart simulation is used to optimize the homogeneity of the field generated by the feedback Merritt\u0000coils and was verified experimentally to be homogeneous within 0.42 % along the racetrack cores' axes. The thermal stability of the sensor's\u0000feedback windings is measured using an insulated container filled with dry\u0000ice inside a coil system. The sensitivity over temperature of the feedback\u0000windings is found to be between 13 and 17 ppm ∘C−1. The sensor's three axes maintain orthogonality to within\u0000at most 0.015∘ over a temperature range of −45 to 20 ∘C. Tesseract's cores achieve a magnetic noise floor of 5 pT √Hz−1 at 1 Hz. Tesseract will be flight demonstrated on the\u0000ACES-II sounding rockets, currently scheduled to launch in late 2022 and\u0000again aboard the TRACERS satellite mission as part of the MAGIC technology\u0000demonstration which is currently scheduled to launch in 2023.\u0000","PeriodicalId":48742,"journal":{"name":"Geoscientific Instrumentation Methods and Data Systems","volume":" ","pages":""},"PeriodicalIF":1.8,"publicationDate":"2022-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45104191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. Cloud computing is becoming increasingly popular in the IT business because of its higher performance, widespread access, cheap cost, and other benefits. It is also a pay-as-you-go approach; hence, anyone can access cloud data from anywhere, and it is employed in education platforms for online classes due to its ease of use. However, many educational institutions hesitate to use the cloud educational platform due to security and privacy issues. Hence in this study, the performance analysis of various cryptographic algorithms such as Elliptic Curve Cryptography (ECC), Advanced encryption standard (AES), Two Fish, Blowfish, Data Encryption Standard (DES), Triple Data Encryption Standard (TDES) and role-based access control (RBAC) was analyzed and compared with each other in a view to ensuring the protection of cloud data storage used for educational purpose in the NPTEL database. Encryption time, decryption time, and retrieval time with different data sizes were used as performance evaluation factors to figure out the best End-To-End Encryption security in a network system. Moreover, an ElGamal SBO with Delta Competitive NN Cryptography has been proposed in which ElGamal Stag beetle optimization performs ElGamal encryption with the generation of an optimized key with low execution time, thereby allowing only authorized users to access the educational data in the cloud and the data transmission has been secured using Delta Competitive NN that minimizes vulnerable attacks while controlling the decryption activity. Results showed that the proposed ElGamal SBO with Delta Competitive NN Cryptography performs better than all other techniques in terms of retrieval time, encryption time, communication cost, computational overhead and decryption time and hence when applied in a security scenario, it can improve the encryption effectiveness.
{"title":"An Analytical approach for optimal secured data storage on cloud server for online education platform","authors":"R. Soundhara Raja Pandian, Christopher Columbus","doi":"10.5194/gi-2022-15","DOIUrl":"https://doi.org/10.5194/gi-2022-15","url":null,"abstract":"<strong>Abstract.</strong> Cloud computing is becoming increasingly popular in the IT business because of its higher performance, widespread access, cheap cost, and other benefits. It is also a pay-as-you-go approach; hence, anyone can access cloud data from anywhere, and it is employed in education platforms for online classes due to its ease of use. However, many educational institutions hesitate to use the cloud educational platform due to security and privacy issues. Hence in this study, the performance analysis of various cryptographic algorithms such as Elliptic Curve Cryptography (ECC), Advanced encryption standard (AES), Two Fish, Blowfish, Data Encryption Standard (DES), Triple Data Encryption Standard (TDES) and role-based access control (RBAC) was analyzed and compared with each other in a view to ensuring the protection of cloud data storage used for educational purpose in the NPTEL database. Encryption time, decryption time, and retrieval time with different data sizes were used as performance evaluation factors to figure out the best End-To-End Encryption security in a network system. Moreover, an ElGamal SBO with Delta Competitive NN Cryptography has been proposed in which ElGamal Stag beetle optimization performs ElGamal encryption with the generation of an optimized key with low execution time, thereby allowing only authorized users to access the educational data in the cloud and the data transmission has been secured using Delta Competitive NN that minimizes vulnerable attacks while controlling the decryption activity. Results showed that the proposed ElGamal SBO with Delta Competitive NN Cryptography performs better than all other techniques in terms of retrieval time, encryption time, communication cost, computational overhead and decryption time and hence when applied in a security scenario, it can improve the encryption effectiveness.","PeriodicalId":48742,"journal":{"name":"Geoscientific Instrumentation Methods and Data Systems","volume":"92 10","pages":""},"PeriodicalIF":1.8,"publicationDate":"2022-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138505351","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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