Induction Measurements Research Articles

Hydrogen production capabilities of lichens micro-ecosystem under extreme salinity, crystalline salt exposure, and simulated Mars-like conditions

This work aims to demonstrate the extremophilic behavior of the lichen Pleurosticta acetabulum at extreme salinities, while maintaining its metabolic capacity to produce hydrogen. Lichen is a special micro-ecosystem that includes mostly a fungus and a green alga or cyanobacterium, as well as a microbiome. The peculiarity of this symbiotic system is its ability to dry out completely and stay inactive to survive harsh conditions. Lichens that had been dehydrated for six months revived quickly when rehydrated, restoring their photosynthetic efficiency and ability to produce hydrogen. The lichen microbiome was crucial for hydrogen production, especially through dark fermentation. The experiments of this work showed that lichen during its exposure to different salinity conditions (0%NaCl – control, 3,5%NaCl – sea salt concentration, 36%NaCl – saturated salt concentration), but also after exposure to crystalline salt (100%NaCl) could maintain the structure and the functionality of its photosynthetic apparatus. This was tested using chlorophyll a fluorescence induction measurements. Based on the results of thermal conductivity gas chromatography (GC-TCD) for the determination of hydrogen production, it was shown that despite being exposed to extreme salinity conditions, lichens maintained its ability to produce hydrogen. The experimental combination of lichen exposure to extreme salinities (up to 100% NaCl), with an extreme atmosphere (100% CO2) and low atmospheric pressure (<10mbar), simulating Mars conditions, highlighted the functional potential of the lichen for survival in a Mars-like environment. This lichen’s ability to withstand extreme conditions and to produce large amounts of hydrogen, makes it a promising candidate for future biotechnological applications, even in challenging environments like Mars, opening new astrobiological and astrobiotechnological perspectives.

Aluminum dust concentration detection based on LSTM-Kalman filter

Industrial dust emissions present serious hazards, including respiratory issues and explosion risks. Traditional dust concentration detection methods are often compromised by environmental factors. This study introduces a novel FFT-KF-LSTM-NET model to predict high-concentration aluminum powder levels, utilizing 128 sets of electrostatic induction measurement data. By applying the Fast Fourier Transform (FFT) to eliminate low-frequency interference, integrating Long Short-Term Memory (LSTM) networks for advanced time series analysis, and using the Kalman Filter (KF) for rapid model convergence, this approach significantly enhances prediction accuracy. The model achieves an 82% improvement in Mean Squared Error (MSE), reducing it to 0.1336, outperforming traditional methods. Furthermore, by modeling the voltage signal generated by charged dust particles in the electrostatic induction sensor's sensing area and using the first derivative of the voltage signal as a learning feature, the model's prediction speed is increased from 1.5 s-2 s–0.5 s, with improved anti-interference capabilities. These advancements position the FFT-KF-LSTM-NET model as a crucial tool for real-time, reliable dust concentration detection in industrial environments.

Performance of a Radio-Frequency Two-Photon Atomic Magnetometer in Different Magnetic Induction Measurement Geometries.

Measurements monitoring the inductive coupling between oscillating radio-frequency magnetic fields and objects of interest create versatile platforms for non-destructive testing. The benefits of ultra-low-frequency measurements, i.e., below 3 kHz, are sometimes outweighed by the fundamental and technical difficulties related to operating pick-up coils or other field sensors in this frequency range. Inductive measurements with the detection based on a two-photon interaction in rf atomic magnetometers address some of these issues as the sensor gains an uplift in its operational frequency. The developments reported here integrate the fundamental and applied aspects of the two-photon process in magnetic induction measurements. In this paper, all the spectral components of the two-photon process are identified, which result from the non-linear interactions between the rf fields and atoms. For the first time, a method for the retrieval of the two-photon phase information, which is critical for inductive measurements, is also demonstrated. Furthermore, a self-compensation configuration is introduced, whereby high-contrast measurements of defects can be obtained due to its insensitivity to the primary field, including using simplified instrumentation for this configuration by producing two rf fields with a single rf coil.

Multi‐Method Structural Investigation of the Schneiderberg–Baalberge Burial Mound (Saxony‐Anhalt, Germany) Including Seismic Full‐Waveform Inversion (FWI)

ABSTRACTThe construction history and subsequent usage of burial mounds are an important testimony for socio‐economic transformation in prehistoric societies. The Baalberge–Schneiderberg burial mound, subject of the presented study, falls in this category as it is considered as an important monument that indicates the emergence of early social stratification during the Chalcolithic period in central Europe. This hypothesis relies on the chronological development of the burial mound, which is not fully understood until now. Therefore, a reconstruction of the complex stratigraphy of the burial mound including construction phases and later alterations is highly relevant for archaeological research, but the required excavations would be onerous and inconsistent with preservation efforts. In this paper, we demonstrate that non‐invasive geophysical prospection, especially seismic sounding with shear and Love waves, is suitable to obtain the required stratigraphic information, if seismic full waveform inversion (FWI) and reflection imaging are applied. Complementary information on the preservation state of the mound is obtained through Electrical Resistivity Tomography (ERT) and Electromagnetic Induction (EMI) measurements. To support the seismic and geoelectric results, we utilize Dynamic Testing (DynP), geoarchaeological corings, 14C‐Dating and archaeological records. Our investigations reveal two construction phases of the Baalberge–Schneiderberg mound. The 14C‐Dating yields dates for the older burial mound that are contemporary to the Chalcolithic Baalberge group (4000–3400 bc). During the Early Bronze Age (EBA), the mound was enlarged to its final size by people of the Aunjetitz/Únětice society (2300–1600 bc). However, both seismic and geoelectric depth sections show an extensive disturbance of the original stratigraphy due to former excavations. For this reason, the exact shape of the older burial mound cannot be determined exactly. Based on our data, we estimate that its height was below 2 m. In consequence, the original Baalberge burial mound was less monumental as until now assumed, which potentially prompting a revision of its significance as indicator for social differentiation.

Estimation of electrical conductivity models using multi-coil rigid-boom electromagnetic induction measurements

Electromagnetic induction measurements from multi-coil configuration instruments are used to obtain information about the electrical conductivity distribution in the subsurface. The resulting inverse problem might not have a unique and stable solution. In that case, a local inversion method can be trapped in a local minimum and lead to an incorrect solution. In this study, we evaluate the well-posedness of the inverse problem for two and three-layered electrical conductivity models. We show that for a two-layered model, uniqueness is ensured only when both in-phase and quadrature data are available from the measurements. Results from a Gauss–Newton inversion and a lookup table demonstrate that the solution space is convex. Furthermore, we demonstrate that for even a simple three-layered model, the data contained in such measurements are insufficient to reach a correct or stable solution. For models with more than 2 layers, independent prior information is necessary to solve the inverse problem. The insights from the numerical examples are applied in a field case.

Changes in magnetic characteristics of pipes during hydraulic and pneumatic tests of trunk pipelines

To identify the zones with the highest tensile stresses and deformations, a two-parameter magnetic method based on the measurement of coercive force and residual magnetic induction was applied. For realization of the method a mobile hardware and software complex DIUS-1.21M with an electromagnetic U-transducer was used, which was located along the pipe axis and along the pipe ring. Measurements were carried out on three pipes: in the first one magnetic characteristics were measured in the absence and under the influence of internal pressure; in the second and third ones — before the test and after the pipe fracture. It was revealed that internal pressure leads to the growth of residual magnetic induction in all zones both along the axis and along the ring, which indicates the occurrence of axial and circular tensile stresses in these zones, and the change of coercivity occurred ambiguously. It was found that fracture significantly increases the scatter of magnetic characteristics, which is explained by the complex nature of the stress-strain state of the fractured object.

Determination of the magnetic penetration depth with measurements of the vortex-penetration field for type-II superconductors

Using a known distribution of the Meissner currents over the surface of an infinitely long superconducting slab with a rectangular cross section, we find an applied magnetic field at which vortices begin to penetrate into the superconductor. This vortex-penetration field is determined by an interplay of the geometrical and Bean-Livingston barriers. The obtained results enable one to find the lower critical field and the London penetration depth from measurements of the magnetic induction on the surface of the superconducting slab, using, e.g., the micro-Hall probes. Published by the American Physical Society 2024

Characteristics of Controlled Bridge Circuit and Its Application in Magnetic Field Induction Measurement

Characteristics of Controlled Bridge Circuit and Its Application in Magnetic Field Induction Measurement

Instantaneous AC Loss and Inductance Measurement of HTS Coil With Finite-Data-Window Least Squares

Instantaneous AC Loss and Inductance Measurement of HTS Coil With Finite-Data-Window Least Squares

A 10 µH Inductance Standard in PCB Technology with Enhanced Protection against Magnetic Fields

Low-frequency working standards of inductance are generally uniformly wound toroids on a ceramic core. Planar inductors made using printed circuit board (PCB) technology are simple and cheap to manufacture in comparison to inductors wound on toroid cores, but they are significantly prone to the influence of external magnetic fields. In this paper, we propose the design of a PCB inductance working standard of 10 μH, consisting of a duplex system of planar PCB coils, electrostatic shielding, and an enclosure. Alongside an electromagnetic analysis and design procedure, the measurements on the manufactured prototype included the generated magnetic field, the thermal time constant of the enclosure, temperature coefficients, and its error analysis. The measurements show negligible generated magnetic fields (&lt;1.68 nT at 7 cm, 49 mA, 10 kHz). The minimum thermal time constant of the enclosure is 1270 s and the temperature coefficient of resistance is 0.00384 1/℃. The presented method of temperature coefficient measurement using a climate chamber allows for measurements in the temperature range of 10 °C to 40 °C. In this temperature range, the results show an inductance variation of 0.05 µH at 50 kHz, while the uncertainty of inductance measurement at this frequency was 0.03 µH (k = 2).

Participatory Systems Thinking to Elucidate Drivers of Food Access and Diet Disparities among Minoritized Urban Populations.

The purpose of this study was to use participatory systems thinking to develop a dynamic conceptual framework of racial/ethnic and other intersecting disparities (e.g., income) in food access and diet in Philadelphia and to identify policy levers to address these disparities. We conducted three group model building workshops, each consisting of a series of scripted activities. Key artifacts or outputs included qualitative system maps, or causal loop diagrams, identifying the variables, relationships, and feedback loops that drive diet disparities in Philadelphia, Pennsylvania. We used semi-structured methods informed by inductive thematic analysis and network measures to synthesize findings into a single causal loop diagram. There were twenty-nine participants with differing vantages and expertise in Philadelphia's food system, broadly representing the policy, community, and research domains. In the synthesis model, participants identified 14 reinforcing feedback loops and one balancing feedback loop that drive diet and food access disparities in Philadelphia. The most highly connected variables were upstream factors, including those related to racism (e.g., residential segregation) and community power (e.g., community land control). Consistent with existing frameworks, addressing disparities will require a focus on upstream social determinants. However, existing frameworks should be adapted to emphasize and disrupt the interdependent, reinforcing feedback loops that maintain and exacerbate disparities in fundamental social causes. Our findings suggest that promising policies include those that empower minoritized communities, address socioeconomic inequities, improve community land control, and increase access to affordable, healthy, and culturally meaningful foods.

How to study psychological mechanisms of mania? Asystematic review on the methodology of experimental studies on manic mood dysregulation of leading theories on bipolar disorder.

Although there are several psychological theories on bipolar disorders (BD), the empirical evidence on these theories through experimental studies is still limited. The current study systematically reviews experimental methods used in studies on the main theories of BD: Reward Hypersensitivity Theory (RST) or Behavioral Activation System (BAS), Integrative Cognitive Model (ICM), Positive Emotion Persistence (PEP), Manic Defense theory (MD), and Mental Imagery (MI). The primary aim is to provide an overview of the used methods and to identify limitations and suggest areas of improvement. A systematic search of six databases until October 2023 was conducted. Study selection involved two independent reviewers extracting data on experimental study design and methodology. A total of 84 experimental studies were reviewed. BAS and RST were the most frequently studied theories. The majority of these experimental studies focus on mechanisms of reward sensitivity. Other important elements of the reviewed theories, such as goal setting and-attainment, situation selection (avoidance or approach), activation, affective/emotional reactivity, and regulatory strategies, are understudied. Self-report and neuropsychological tasks are most often used, while mood induction and physiological measures are rarely used. There is a need for more consensus on the operationalization of psychological theories of mania. Standardization of test batteries could improve comparability among studies and foster a more systematic approach to experimental research. Research on affective (activated) states is still underrepresented in comparison with studies on trait vulnerabilities.

Kinematic changes in dairy cows with induced hindlimb lameness: transferring methodology from the field of equine biomechanics

Lameness is a common issue on dairy farms, with serious implications for economy and animal welfare. Affected animals may be overlooked until their condition becomes severe. Thus, improved lameness detection methods are needed. In this study, we describe kinematic changes in dairy cows with induced, mild to moderate hindlimb lameness in detail using a “whole-body approach”. Thereby, we aimed to identify explicable features to discriminate between lame and non-lame animals for use in future automated surveillance systems. For this purpose, we induced a mild to moderate and fully reversible hindlimb lameness in 16 dairy cows. We obtained 41 straight-line walk measurements (containing > 3 000 stride cycles) using 11 inertial measurement units attached to predefined locations on the cows’ upper body and limbs. One baseline and ≥ 1 induction measurement(s) were obtained from each cow. Thirty-one spatial and temporal parameters related to limb movement and inter-limb coordination, upper body vertical displacement symmetry and range of motion (ROMz), as well as pelvic pitch and roll, were calculated on a stride-by-stride basis. For upper body locations, vertical within-stride movement asymmetry was investigated both by calculating within-stride differences between local extrema, and by a signal decomposition approach. For each parameter, the baseline condition was compared with induction condition in linear mixed−effect models, while accounting for stride duration. Significant difference between baseline and induction condition was seen for 23 out of 31 kinematic parameters. Lameness induction was associated with decreased maximum protraction (−5.8%) and retraction (−3.7%) angles of the distal portion of the induced/non-induced limb respectively. Diagonal and lateral dissociation of foot placement (ratio of stride duration) involving the non-induced limb decreased by 8.8 and 4.4%, while diagonal dissociation involving the induced limb increased by 7.7%. Increased within-stride vertical displacement asymmetry of the poll, neck, withers, thoracolumbar junction (back) and tubera sacrale (TS) were seen. This was most notable for the back and poll, where a 40 and 24% increase of the first harmonic amplitude (asymmetric component) and 27 and 14% decrease of the second harmonic amplitude (symmetric component) of vertical displacement were seen. ROMz increased in all these landmarks except for TS. Changes in pelvic roll main components, but not in the range of motion of either pitch or roll angle per stride, were seen. Thus, we identified several kinematic features which may be used in future surveillance systems. Further studies are needed to determine their usefulness in realistic conditions, and to implement methods on farms.

Retraction Note to: Theoretical and experimental approach in poloidal beta and internal inductance measurement on IR-T1 tokamak

Retraction Note to: Theoretical and experimental approach in poloidal beta and internal inductance measurement on IR-T1 tokamak

Polarization of radio-frequency magnetic fields in magnetic induction measurements with an atomic magnetometer

Polarization of radio-frequency magnetic fields in magnetic induction measurements with an atomic magnetometer

Assessing the Impact of Brackish Water on Soil Salinization with Time-Lapse Inversion of Electromagnetic Induction Data

Over the last decade, electromagnetic induction (EMI) measurements have been increasingly used for investigating soil salinization caused by the use of brackish or saline water as an irrigation source. EMI measurements proved to be a powerful tool for providing spatial information on the investigated soil because of the correlation between the output geophysical parameter, i.e., the electrical conductivity, to soil moisture and salinity. In addition, their non-invasive nature and their capability to collect a high amount of data over broad areas and in a relatively short time makes these measurements attractive for monitoring flow and transport dynamics, which are otherwise undetectable with conventional measurements. In an experimental field, EMI measurements were collected during the growth season of tomatoes and irrigated with three different irrigation strategies. Time-lapse data were collected over three months in order to visualize changes in electrical conductivity associated with soil salinity. A rigorous time-lapse inversion procedure was set for modeling the soil salinization induced by brackish irrigation water. A clear soil response in terms of an increase in electrical conductivity (EC) in the upper soil layer confirmed the reliability of the geophysical tool to predict soil salinization trends.

Electromagnetic estimation of mechanical stress in steel elements by using magnetic induction

We present here experimental verification of a theoretical model previously developed to estimate internal mechanical stress in steel-based elements by means of non-contact electromagnetic induction measurements. Results confirm the validity of the proposed model and demonstrate that stress below 50% of the elastic limit can be detected with standard electronics.

In situ conductometry for studying the homogenization of Al-Mg-Si alloys and predicting extrudate grain structure through machine learning

In industrial practice, no sensors capable of obtaining microstructural information in situ during thermo-mechanical processing of Al alloys are commonly employed. Inductive electrical conductivity measurement is safe, inexpensive, and capable of acquiring valuable information about precipitation and dissolution processes. However, commercial eddy current sensors work only at low temperatures near room temperature and are thus not suitable for in situ conductometry during heat treatments of Al alloys. We designed a high-temperature eddy current sensor and performed in situ conductometry during the homogenization of six Al-Mg-Si wrought alloys, three of which are experimental recycling-friendly alloys with increased Fe content. The results are interpreted with regard to microstructural investigations, and the advantages and limitations of our approach are discussed. As a proof-of-concept, we show how the conductivity curves and extrusion process parameters can be combined to predict final extrudate grain structures using machine learning. To achieve this, we employed finite element simulation of extrusion coupled with microstructural simulation over a wide parameter range, validated by extrusion experiments and metallography, and trained a feedforward neural network. We believe our interdisciplinary approach can lead to improvements in the industrial processing of Al wrought alloys.

Acclimation mechanism of microalgal photosynthetic apparatus under low atmospheric pressures - new astrobiological perspectives in a Mars-like atmosphere.

This study reveals a new acclimation mechanism of the eukaryotic unicellular green alga Chlorella vulgaris in terms of the effect of varying atmospheric pressures on the structure and function of its photosynthetic apparatus using fluorescence induction measurements (JIP-test). The results indicate that low (400mbar) and extreme low (2 atmosphere (simulating the Mars atmosphere), reveals that the impact of extremely low atmospheric pressure on PQ mobility within the photosynthetic membrane, coupled with the low density of an almost 100% CO2 Mars-like atmosphere, results to a similar photosynthetic efficiency to that on Earth. These findings pave the way for the identification of novel functional acclimation mechanisms of microalgae to extreme environments that are vastly distinct from those found on Earth.

High Accuracy Localization for Miniature Ingestible Devices Using Mutual Inductance.

This article demonstrates an inductively coupled high-accuracy localization system for miniature ingestible devices. It utilizes an inductance double capacitances-series capacitance (LCC-S) compensation architecture that enables mutual inductance measurement at primary side that is positioned outside the human body and less constrained by power budget and size than the miniature ingestible. Depending on the secondary circuit architecture, only limited and simple cooperative measurements are needed from the ingestible secondary side, which saves power and area in the miniature device. The errors in the system are modeled thoroughly, providing insights about system require-ments for a particular localization accuracy target for efficient design and to identify key building blocks with large influence on overall performance. The model shows that sub-centimeter localization root-mean-square error (RMSE) can be achieved with a modest external ADC (18bit) using three primary coils and three secondary coils. The localization is verified along a complete small intestine tract with realistic dimensions. The proposed model is verified by simulation and experiment showing that at the selected frequency range up to 5 MHz the body has no influence on the accuracy. The use of 0.9% saline as phantom is proposed which guarantees the analysis validity for all body types.