Field Instrument Research Articles

Enhancing jointed plain concrete pavement performance analysis through remote data collection on oversize/overweight vehicles: evaluating damage costs and reduced service life

ABSTRACT A large gap exists between actual performance of in-situ Jointed Plain Concrete Pavement (JPCP) and mechanistic models for predicting performance under environmental and traffic loads. JPCP response measurement using instrumented sensors and data acquisition systems is one of the most reliable approaches to bridging the gap. Field instrumentation plays a significant role in validating mechanistic models and establishing correlations between input variables related to JPCP distresses. This paper details the steps and methodology of field instrumentation for installing a remote data-acquisition system in conjunction with JPCP reconstruction conducted in Monona County, Iowa. The data acquisition system installed on-site includes a portable weigh-in-motion system and state-of-the-art sensors for evaluating environmental and traffic impacts on the reconstructed JPCP section by measuring pavement responses related to structural distress. A Finite-Element-Method (FEM)-based JPCP model was also developed and validated using in situ data, ensuring that the model accurately reflects in situ conditions of JPCP and can be reliably used for JPCP analysis under Oversize/Overweight (OSOW) vehicle loads. A life-cycle cost analysis was then conducted to quantify the service-life reduction and the associated costs of JPCP damage due to OSOW vehicle traffic, thereby demonstrating economic implications of accommodating OSOW vehicles on JPCP system.

Field measurements and modelling of climate driven hydraulic flux, water content and suction in a loess slope

Rainfall-triggered shallow slope failures are common in New Zealand loess. While often unsaturated, rainfall infiltration reduces suction in the loess as the water content increases, resulting in reduction in shear strength and increased potential for slope instability. Here the hydraulic response of an in-situ loess slope to natural rainfall and evapotranspiration is examined using long term field instrumentation. Data from a 19-month monitoring period show that the loess’ hydraulic behaviour responds to change in seasonal climatic conditions, highlighting the relationship between moisture content and suction with evapotranspiration and infiltration. To simulate the field response, a one-dimensional steady infiltration/evapotranspiration model has been developed, exploiting the unique power laws which interrelate water content, suction and hydraulic conductivity which arise from a loess’s fractal particle and pore size distributions. Hydraulic hysteresis is also accounted for. Closed form expressions are derived for the subsurface suction profile, from which profiles of moisture content, hydraulic conductivity and the suction’s contribution to strength may be obtained. Simulated subsurface water contents are in good agreement with field observations. Furthermore, fluxes across the loess surface used to obtain the modelled quantities are in general agreement with local climatic conditions and their variations during the monitoring period. Modelled and measured data are strongly correlated at shallow depths, having a Pearson correlation coefficient of 0.53.

Size Distribution of Small Grains in the Inner Zodiacal Cloud

The Parker Solar Probe (PSP) spacecraft has transited the innermost regions of the zodiacal cloud and detects impacts to the spacecraft body via its electric field instrument. Multiple dust populations have been proposed to explain the PSP dust impact rates. PSP’s unique orbit allows us to identify a region where the impact rates are likely dominated by α-meteoroids, small zodiacal grains on approximately circular, bound orbits. From the distribution of voltage signals generated by dust impacts to PSP in this region, we find the cumulative mass index for grains with radii of ∼0.6–1.4 μm (masses of 3 × 10−15 kg to 3 × 10−14 kg) to be α = 1.1 ± 0.3 from 0.1 to 0.25 au. The cumulative mass index increases toward the Sun, with even smaller fragments generated closer to the Sun. The derived size distribution is steeper than previously estimated, and in contrast to expectations, we find that most of the dust mass resides in the smallest fragments and not in large grains inside 0.15 au. As the innermost regions of the zodiacal cloud are likely collisionally evolved, these results place new constraints on how the solar system’s zodiacal cloud and, by extension, astrophysical debris disks are partitioned in mass.

The Role of Micro Propulsion in Enabling Autonomous Operations of Nanosatellites

Micro-Electro-Mechanical Systems (MEMS)-based propulsion devices have significant potential for providing high specific power. The application of Micro Power Generation technology to space propulsion systems can enhance orbit and station-keeping capabilities, potentially at lower costs. New-generation spacecraft and satellites are becoming smaller and require micro-propulsion systems for all aspects of their operations. The development of micro-propulsion systems with associated combustors for micro-electricity generation, utilizing liquid fuel, presents major challenges in fuel injection, mixing, combustion, and chemical reactor systems. A micro-spacecraft with high-accuracy station-keeping and attitude control capabilities needs to have low mass and deliver small impulses. Each nanosatellite will weigh a maximum of 10 kg, including the propellant mass. Provisions for orbital manoeuvres, attitude control, multiple sensors, and instruments, along with full autonomy, will result in a highly capable miniaturized satellite. All onboard electronics will endure a total radiation dose of 100 k rads over a two-year mission lifetime. Nanosatellites designed for in-situ measurements will be spin-stabilized and equipped with a complement of particles and fields instruments. Nanosatellites intended for remote measurements will be three-axis stabilized and equipped with imaging and radio wave instruments. Key technologies under development include: advanced, miniaturized chemical propulsion systems; miniaturized sensors; highly integrated, compact electronics; autonomous onboard and ground operations; miniaturized onboard orbit determination methods; onboard RF communications capable of transmitting data to Earth from significant distances; lightweight and efficient solar array panels; lightweight, high-output battery cells; a miniaturized heat transport system; lightweight yet strong composite materials for nano-satellite and deployer-ship structures; and simple, reusable ground systems.

A Neurosurgical Instrument Segmentation Approach to Assess Microsurgical Movements.

The ability to recognize anatomical landmarks, microsurgical instruments, and complex scenes and events in a surgical wound using computer vision presents new opportunities for studying microsurgery effectiveness. In this study, we aimed to develop an artificial intelligence-based solution for detecting, segmenting, and tracking microinstruments using a neurosurgical microscope. We have developed a technique to process videos from microscope camera, which involves creating a segmentation mask for the instrument and subsequently tracking it. We compared two segmentation approaches: (1) semantic segmentation using Visual Transformers (pre-trained domain-specific EndoViT model), enhanced with tracking as described by Cheng Y. et al. (our proposed approach), and (2) instance segmentation with tracking based on the YOLOv8l-seg architecture. We conducted experiments using the CholecSeg8k dataset and our proprietary set of neurosurgical videos (PSNV) from microscope. Our approach with tracking outperformed YOLOv8l-seg-based solutions and EndoViT model with no tracking on both CholecSeg8k (mean IoT = 0.8158, mean Dice = 0.8657) and PSNV (mean IoT = 0.7196, mean Dice = 0.8202) datasets. Our experiments with identifying neurosurgical instruments in a microscope's field of view showcase the high quality of these technologies and their potential for valuable applications.

Shared decision-making in long-term care: A systematic review of assessment instruments

This systematic review explored the instruments used to measure Shared Decision Making (SDM) within long-term care (LTC) settings. Relevant publications from the period between January 2000 and October 2022 were searched across five databases. Thirty-six SDM assessment instruments were identified, which encompassed those measuring SDM for LTC recipients/family caregivers and/or healthcare providers. These instruments were either specifically tailored for LTC settings or more broadly applicable across healthcare contexts, including LTC. In terms of psychometric properties of the instruments, internal consistency reliability, content validity, structural validity, and hypothesis testing were commonly tested. The findings of this research can aid health researchers, managers, and scholars in choosing suitable instruments for assessing SDM in specific LTC scenarios, considering factors such as measurement scope, assessment methods, and instrument reliability. Additionally, these findings offer valuable insights for the future development of high-quality SDM assessment instruments in LTC field.

LANDSLIDE DETECTION AND MONITORING TECHNIQUES: A BIBLIOMETRIC ANALYSIS AND FUTURE DIRECTIONS

The devastating consequences of landslides demand rigorous assessment and effective management strategies to minimise risks. In this context, landslide detection and monitoring are crucial in identifying potential hazards and implementing proactive mitigation measures. This study uses the Scopus database to present a bibliometric analysis of 1,112 peer-reviewed journal articles on landslide detection and monitoring techniques published between 2002 and 2022. The analysis reveals a remarkable surge in publications, from 4 in 2002 to 180 in 2022, with the last five years (2018-2022) accounting for over 60% of the total publications. Over 3,259 unique researchers from 75 countries contributed to this field, with a significant portion originating from Asia, Europe, and North America. China and Italy emerged as the leading countries, producing over half of the articles. Nicola Casagli, from Italy, authored the most publications and garnered the highest number of citations. Remote Sensing emerged as the most preferred journal for authors, while Landslides garnered the highest total citations, and Geomorphology has the most normalised citations per article. The Chinese Academy of Sciences, China University of Geosciences, and the University of Florence in Italy were the most productive research institutions. The Natural Science Foundation of China (NSFC) emerged as the top funding agency. “Landslide”, “landslide monitoring”, and “early warning systems” were the top three most frequently used keywords. Keyword analysis identified landslide detection and monitoring advancements in remote sensing, analytical methods, and in-situ techniques. Co-occurrence analysis of trending research terms highlighted three distinct thematic clusters: remotely sensed data with machine learning and image analysis for landslide detection, field instrumentation for continuous deformation monitoring, and development of early warning systems for landslide hazard assessment and mitigation.

Deriving iceberg ablation rates using an on-iceberg autonomous phase-sensitive radar (ApRES)

Abstract The increase in iceberg discharge into the polar oceans highlights the importance of understanding how quickly icebergs are deteriorating and where the resulting freshwater injection is occurring. Recent advances in quantifying iceberg deterioration through combinations of modeling, remote sensing and direct in situ measurements have successfully calculated overall ablation rates, and surface and sidewall ablation; however, in situ measurements of basal melt rates have been difficult to obtain. Radar has successfully measured iceberg thickness, but repeat measurements, which would capture a change in iceberg thickness with time, have not yet been collected. Here we test the applicability of using an on-iceberg autonomous phase-sensitive radar (ApRES) to quantify basal ablation rates of a large (~800 m long) non-tabular Arctic iceberg during an intensive 2019 summer field campaign in Sermilik Fjord, southeast Greenland. We find that ApRES can be used to measure basal ablation even over a short deployment period (10 d), and also provide a lower bound on sidewall melt. This study fills a critical gap in iceberg research and pushes the limits of field instrumentation.

A CRITICAL ANALYSIS OF THE THEMATIC CONCERNS ADDRESSED BY THE AUTHORS THAT REVEAL THE GENDER ISSUES IN THE RIVER BETWEEN AND THE RIVER AND THE SOURCE

<p>The study focuses on two novels that were written by a premier first-generation writer and another authored by a third-generation one. The study examines thematic concerns that reveal the images of women in Kenyan literature. The study involves the analysis of the language used by characters and the writers' view on gendered societal paradigms that embody characterization as a backdrop for the analysis of the said texts, more so on the position of women in Kenyan society through the two writers’ eyes. The study objective is to explore the thematic concerns addressed by the authors that reveal the gender issues in <em>The River Between</em> and <em>The River and The Source</em>. The study adopted liberal feminism. The methodology was confined to a contextual approach that was conducted in the library search modalities. As such, no field instruments were used.</p><p> </p><p><strong> Article visualizations:</strong></p><p><img src="/-counters-/soc/0699/a.php" alt="Hit counter" /></p>

Two‐Spacecraft Observations of Asymmetric Martian Bow Shock: Conjunctions of Tianwen‐1 and MAVEN

AbstractThe Martian bow shock has been extensively studied through magnetic field and plasma instrument observations from various Mars space missions. However, prior investigations primarily involve statistical analyses based on single spacecraft crossings, leaving the asymmetry of the Martian bow shock unstudied through simultaneous two‐spacecraft observations. In this study, utilizing simultaneous observations from Tianwen‐1 and MAVEN, we examine the instantaneous asymmetry of the Martian bow shock. We present the asymmetry of the Martian bow shock in the Mars‐Solar‐Electric and Mars‐Solar‐Orbital reference frames, possibly influenced by the solar wind motional electric field and Martian crustal magnetic field, respectively. Moreover, we suggest that the bow shock exhibits increased asymmetry under stronger solar wind motional electric field conditions. This study highlights how a two‐point observation approach offers valuable insights into the dynamic behavior of the Martian induced magnetosphere.

Prevalence and Propagation of Lightning‐Generated Whistlers in Van Allen Probes EFW Burst Data

AbstractWe assess the prevalence of ducted and non‐ducted whistler propagation using burst mode data from the Van Allen Probes Electric Field and Waves instrument (EFW). We have identified burst periods containing lightning‐generated whistlers (LGWs), resulting in a data set available for future use. The entire burst data set is filtered through an analysis of the search coil magnetometer (SCM) noise, identifying signals in frequency space that exceed an adaptive noise threshold. We implement DBSCAN (Density‐Based Spatial Clustering of Applications with Noise) to identify individual whistlers and clusters of whistlers. With magnetic spectral analysis, we calculate the mean wave normal angle (WNA) for each LGW group. We use ray tracing to estimate the expected WNA distributions for non‐ducted LGWs to compare to the data and determine methods for identifying potentially ducted LGWs. The ray‐tracing results provide a clear threshold in WNA for ducted whistlers. Using this threshold, we estimate that at least of LGWs in this data set are ducted. We find that the majority of potentially ducted whistlers are below and nearly half of LGWs below and within 9–18 MLT may be ducted.

Electrostatic Modeling of Dust Impact Signals Based on the Expanding Plasma Cloud

Signals generated by dust impacting spacecraft can be detected by electric field instruments. These signals have been simulated by numerous models. However, few models can accurately characterize the expansion of the plasma cloud generated by dust impact. The COMSOL model presented in this paper provides a way to understand the expansion properties of ions and electrons. The model can also be used to analyze the various expected waveforms of dust impact signals as a function of different parameters, such as the spacecraft voltage and the ambient plasma temperature. The results show that close to 50% of ions and electrons in the impact plasma cloud are collected by spacecraft at weak spacecraft potentials and that a fraction of the ions is still collected rather than all of them streaming away from the impact location at V SC > 0 V. The model also confirms that in the expanding plasma cloud, ions are in the form of plumes, while electrons diffuse in an isotropic manner.

Time Profile Study of Type III Solar Radio Bursts Using Parker Solar Probe

Solar type III radio bursts are crucial indicators of energetic electron activity in the solar corona and interplanetary space. Our assessment of 43 interplanetary type III bursts, recorded by the FIELDS instrument on board the Parker Solar Probe during Encounters 05 to 11, has led to significant and complex findings. We have analyzed time profile features across a frequency range of 19–0.5 MHz, revealing dependencies on frequency and providing insights into duration, burst speeds, bandwidths, and drift rates. This novel analysis has unveiled a spectral index of −0.63 ± 0.04 for rise, −0.69 ± 0.03 for decay time, and −0.68 ± 0.03 for the total duration. We have determined the average electron beam velocities for front, middle, and back as 0.15c, 0.13c, and 0.08c, respectively. Our findings show that faster electron beams generate emissions with shorter duration. The average ratio of the front-to-back velocity is 1.87, and the ratio of front-to-middle velocity is 1.23. We have also discovered a strong relationship between burst duration with rise, peak, and decay times, particularly pronounced with decay time (correlation coefficient = 0.95). This indicates that the entire temporal profile, including rise, peak, and decay phases, collectively contributes to event duration and is not solely influenced by external factors like plasma conditions or electron beam dynamics but also by internal burst processes. These complex findings shed light on the physical mechanisms governing burst dynamics, revealing intricate interactions between electron beam characteristics and observed temporal and spectral traits of type III solar radio bursts.

Investigation of the global climatologic performance of ionospheric models utilizing in-situ Swarm satellite electron density measurements

The Swarm constellation is a triplet of satellites, flying, since their final configuration reached in April 2014, at altitudes of about 420 to 490 km (the lower pair) and about 500 to 530 km (the upper satellite). All the three satellites provide in-situ measurements of the plasma density in the topside ionosphere using Langmuir Probe sensors onboard the Electrical Field Instrument. The present study is a comprehensive investigation into the climatologic performance of three ionospheric models when compared to the Swarm satellite in-situ measurements. The models are the International Reference Ionosphere (IRI) model, a quick run ionospheric electron density model (NeQuick), and a 3-dimensional electron density model based on artificial neural network training of COSMIC (Constellation Observing System for Meteorology, Ionosphere, and Climate) satellites radio occultation measurements (3D-NN). The mean monthly quiet-time latitudinal profile of Swarm measurements was computed by binning the Swarm electron density measurements in 15-degree longitudes starting from longitude −180° in steps of 15° to 180°, and corresponding model predictions were obtained. The data used in the study covers the years 2014, 2016, 2019, and 2022, capturing various phases of the solar activity cycle. Results from the study show that modelled electron density predictions from all three climatologic models are fairly good representations of the Swarm satellite measurements, with some exceptions in which the models underestimate or overestimate the Swarm satellite values. The IRI model performed best at the northern hemisphere mid latitude, and it overestimated the Swarm measurements at altitudes of ∼ 450 km, especially at the southern hemisphere mid and high latitudes. The NeQuick performed best during the night times, and it overestimated the Swarm measurements, especially at the mid latitudes. The NeQuick was also observed to overestimate the Swarm measurements during the winter solstices at both hemispheres, which is June solstice in the southern hemisphere and December solstice in the northern hemisphere. Overall, the 3D-NN model most often performed better than the IRI model and the NeQuick, especially during the day times and during the high solar activity year (2014), but it underestimated the Swarm measurements, especially at the low and mid latitudes. For all categories explored in the study, the 3D-NN consistently performed better than the other two models. The NeQuick performed better than the IRI model at altitude of satellite B, while the IRI model performed slightly better than the NeQuick at altitude of satellites A and C. The NeQuick also performed better than the IRI model in the local time category, whereas the IRI model performed better than the NeQuick in categories of season, solar activity, and longitudinal sector.

Smart IoT SCADA System for Hybrid Power Monitoring in Remote Natural Gas Pipeline Control Stations

A pipeline network is the most efficient and rapid way to transmit natural gas from source to destination. The smooth operation of natural gas pipeline control stations depends on electrical equipment such as data loggers, control systems, surveillance, and communication devices. Besides having a reliable and consistent power source, such control stations must also have cost-effective and intelligent monitoring and control systems. Distributed processes are monitored and controlled using supervisory control and data acquisition (SCADA) technology. This paper presents an Internet of Things (IoT)-based, open-source SCADA architecture designed to monitor a Hybrid Power System (HPS) at a remote natural gas pipeline control station, addressing the limitations of existing proprietary and non-configurable SCADA architectures. The proposed system comprises voltage and current sensors acting as Field Instrumentation Devices for required data collection, an ESP32-WROOM-32E microcontroller that functions as the Remote Terminal Unit (RTU) for processing sensor data, a Blynk IoT-based cloud server functioning as the Master Terminal Unit (MTU) for historical data storage and human–machine interactions (HMI), and a GSM SIM800L module and a local WiFi router for data communication between the RTU and MTU. Considering the remote locations of such control stations and the potential lack of 3G, 4G, or Wi-Fi networks, two configurations that use the GSM SIM800L and a local Wi-Fi router are proposed for hardware integration. The proposed system exhibited a low power consumption of 3.9 W and incurred an overall cost of 40.1 CAD, making it an extremely cost-effective solution for remote natural gas pipeline control stations.

Investigation of ground subsidence response to an unconventional longwall panel layout

Ground subsidence caused by extraction of longwall panels has always been a great concern all over the world. Conventional longwall mining system (CLMS) gives rise to wavy subsidence causing great damage to surface structures. A coal mine in Shanxi, China, utilizes a split-level longwall layout (SLL) for a sub-horizontal No. 8 coal seam to improve the cavability of mudstone interlayer and top coal. This layout, however, also produced unexpectedly favorable surface subsidence. Subsidence of No. 6 and No. 8 longwall panels was monitored while mining was conducted. Field instrumentation and numerical simulation were carried out. It is demonstrated that an asymmetric subsidence profile with stepped subsidence and cracks occurred on the tailgate side but relatively mild and smooth deformation on the other. Due to elimination of conventional parallelepiped gate pillar, No. 6 and No. 8 gobs were connected. Extraction of two SLL panels acted as one supercritical panel. The maximum possible subsidence was reached which lowers the likelihood of potential future secondary subsidence as underground gob fractures and voids have closed. Therefore, SLL is more favorable for post-mining land reuse as gobs are more consolidated underground.

Whistler Waves in the Young Solar Wind: Statistics of Amplitude and Propagation Direction from Parker Solar Probe Encounters 1–11

In the interplanetary space solar wind plasma, whistler waves are observed in a wide range of heliocentric distances (from ∼20 solar radii (RS) to Jupiter’s orbit). They are known to interact with solar wind suprathermal electrons (strahl and halo) and to regulate the solar wind heat flux through scattering the strahl electrons. We present the results of applying the technique to determine the whistler wave propagation directions to the spectral data continuously collected by the FIELDS instruments on board Parker Solar Probe (PSP). The technique was validated based on the results obtained from burst mode magnetic and electric field waveform data collected during Encounter 1. We estimated the effective length of the PSP electric field antennas for a variety of solar wind conditions in the whistler wave frequency range and utilized these estimates for determining the whistler wave properties during PSP Encounters 1–11. Our findings show that (1) the enhancement of the whistler wave occurrence rate and wave amplitudes observed between 25 and 35 RS is predominantly due to the sunward-propagating whistler wave population associated with the switchback-related magnetic dips; (2) the antisunward or counterpropagating cases are observed at 30–40 RS; (3) between 40 and 50 RS, sunward and antisunward whistlers are observed with comparable occurrence rates; and (4) almost no sunward or counterpropagating whistlers were observed at heliocentric distances above 50 RS.

Statistics and Models of the Electron Plasma Density From the Van Allen Probes

AbstractWe use the full NASA Van Allen Probes mission (2012–2019) to extract the electron plasma density from the Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) and Electric Field and Waves (EFW) instruments and discuss the evolution of the plasmasphere. We generate new statistics including mean and standard deviations of the plasma density with respect to L‐shell, magnetic local time (MLT), and various geomagnetic indices. These statistics are generated to be applied in radiation belt physics and space weather codes (with fits provided). The mean plasmasphere is circular around Earth with respect to MLT for Kp < 1. The mean 100 cm−3 level line is above L = 5 and mean 10 cm−3 level expands above the Van Allen Probes apogee for Kp < 1. The outer electron belt lies within the plasmasphere for 60% of all times. As activity increases (Kp > 2), a gradual MLT asymmetry forms with higher mean density in the afternoon sector due to plumes expanding outward. Conversely, the mean density decreases on the dawn and night sectors. The mean density is between ∼500 and ∼50 cm−3 between L ∼ 4 and L ∼ 6 during quiet and moderately active times (Kp < 3), representing ∼80% of all times. Statistics in regions of high density below L = 2 are underdefined for intense activity. The highest standard deviation of density represents a factor 2.5 to 3 times the mean above L = 5 and for active times. We find the percent difference between the EFW and EMFISIS densities is bounded by ±20% for quiet and moderate activity (Kp < 5) and goes up to ±100% for extreme activity.

Design and development of a scanning magnet for high-resolution mass spectrometry

The magnets play a crucial role in sector mass spectrometers, directly influencing the resolution, sensitivity, and stability of these instruments. This study is based on the design requisites for high-resolution scanning magnet, alongside the optical layout schematics for mass spectrometer instrumentation. The analysis is conducted on the design parameters encompassing magnetic structure, field quality, and response dynamics. Utilizing Opera-3D simulation software, optimization designs are executed for the magnetic structure and performance, resulting in a magnet design exhibiting commendable attributes such as response time, magnetic field distortion characteristics, field range, linearity, and homogeneity. Following the completion of magnet fabrication and assembly, comprehensive evaluations of magnetic field performance and instrument testing are conducted. Results demonstrate good magnetic field linearity and minimal eddy current distortion, with a magnetic field homogeneity reaching up to ±0.05 % within the desired field region. The magnet exhibits versatility across a scan range spanning 7 to 238 u, with a scanning speed of 140 ms. Sensitivity and resolution tests, conducted using In-115, validated the magnet's compliance with the stringent design requirements of high-resolution mass spectrometry scanning magnets.

DS 35 - Preventing Contaminated Surgical Instruments in the Sterile Field: Early Intervention with Operating Room Involvement

DS 35 - Preventing Contaminated Surgical Instruments in the Sterile Field: Early Intervention with Operating Room Involvement