Induction Sensors Research Articles

Zoning of a Newly-Planted Vineyard: Spatial Variability of Physico-Chemical Soil Properties

Soil properties show a high spatio-temporal variability, affecting productivity and crop quality within a given field. In new vineyard plantations, with changes in the initial topographic profile, this variability is exacerbated due to the incorporation of soil from different origins and qualities. The aim of the current study was to characterize the variability of soil properties in a newly established vineyard, and delineating zones for site-specific management of fertilization. For this purpose, the soil apparent electrical conductivity (ECa) in the first 150 cm was measured with an electromagnetic induction sensor. A soil sampling was performed following a regular grid (35 × 35 m, 149 samples), collecting samples down to 40 cm depth for determining soil chemical properties. Spatial variability was assessed through semivariogram calculation and ordinary kriging. The soil properties that better represent the variability in this newly established vineyard were pH, effective cation exchange capacity (ECEC), carbon content, clay and ECa. The ECa was homogeneous all over the vineyard, except for the area closer to the river where a greater human intervention had occurred, with contributions of external soil at a greater depth. Soil properties showed a great spatial variability. Interpolated maps allowed for detecting areas with a lack of nutrients in which a differential fertilization could be performed in search of a sustainable and balanced production. The information provided by the maps of pH, ECEC and carbon and potassium contents allow for performing a differential management of the vineyard in terms of fertilization. In addition, the results obtained suggest that the vineyard should be divided into two sectors for a differential irrigation management. The ECa was not significantly correlated to most of the soil properties determined in the current study; however, it allowed for a low-cost mapping of the vineyard soil and established large areas of management within the vineyard.

Map-based site-specific seeding of seed potato production by fusion of proximal and remote sensing data

Uniform rate seeding (URS), adopted by the majority of farmers worldwide, is an inappropriate approach particularly in fields with large variability to optimize seeding rate that is crucial to manage farm resources sustainably. The objective of this study was to examine the potential of map-based site-specific seeding (SSS) of seed potato for improving crop yield and economic return. A 6-ha-field was scanned using an on-line visible and near infrared (vis-NIR) spectroscopy and an electromagnetic induction (EMI) sensor. Two SSS treatments were adopted based-on two types of management zone (MZ) maps, delineated with K-means clustering algorithm, and these were compared with the URS. The first treatment was based on a MZ map developed using EMI data (EMI-SSS), whereas the second treatment was based on fusion of vis-NIR measured soil data with Sentinel-2 derived normalized difference vegetation index (visNIRsen-SSS). Seed potatoes (Solanum tuberosum L. cv. Hermes) were planted at 11, 13, 15, 17 and 19 cm seed-to-seed spaces according to “Kings” principle i.e., sowing more seeds to the most fertile zones and vice-versa. Results showed that both SSS approaches have resulted in increased tuber yields (EMI-SSS: 32.42 t/ha, visNIRsen-SSS: 31.89 t/ha) and higher economic return, compared to URS . Although visNIRSen-SSS provided lower gross yield than EMI-SSS, the larger yield of small size (28−45 mm) tubers, having higher market price than other size categories has resulted in actual market price for the former being higher than that of the latter approach. The visNIRsen-SSS and EMI-SSS produced net returns of 4995 €/ha and 4947 €/ha, respectively, which were more than that of the URS of 4528 €/ha, by 467 €/ha and 419 €/ha, respectively. In addition, visNIRsen-SSS approach has saved seeding costs by 14 €/ha though EMI-SSS consumed 5 €/ha more compared to URS. Therefore, it is recommended to adopt SSS (particularly visNIRsen-SSS) for seed potato production, as a means of increasing crop yield, reducing input cost and thus maximizing profitability compared to URS.

Impact of Arctic sea ice floe-scale anisotropy on airborne electromagnetic surveys

AbstractAirborne electromagnetic induction sensors have demonstrated their extensive capacities to measure sea-ice thickness distributions. However, biases can emerge when comparing these 1-D measurements to a broader 2-D regional scale due to the spatial anisotropy inherent to sea-ice cover. Automated processing of available sea-ice maps could significantly ease the decision on how to set up an optimised flight pattern, which would result in representative ice thickness numbers for the region. In this study, first we investigate the extent to which the sea-ice anisotropy can influence the representativeness of an airborne survey compared to the regional situation. Second, we propose a method to process sea-ice maps prior to flights to help preparing the most representative flight plan possible for the local area. The method is based on automated segmentation of radar satellite images and extensive simulation of flight transects over the image. The spatial analysis of these transects enables for the identification of the most representative survey trajectories for the area. The method was applied for seven different synthetic aperture radar satellite images over Arctic sea ice north of Svalbard. The results indicate that the proposed method improved the representativeness of the airborne survey by identifying the most suitable transect over the ice pack.

Map-based site-specific seeding of consumption potato production using high-resolution soil and crop data fusion

Maximizing potato productivity and economic return calls for a proper seeding technology that is capable to manage in-field soil variability by optimizing the input seed densities. Current study evaluates the agronomic and economic potential of site-specific seeding (SSS) of consumable potato in comparison with uniform rate seeding (URS) approach. Two treatments of map-based SSS were tested in two study sites i.e., Dal (5.5 ha) and Bottelare (5.4 ha) in Belgium. In the first treatment, soil apparent electrical conductivity measured with an electromagnetic induction (EMI) sensor (EMI-SSS) was used as the management zone proxy data, and in the second treatment, soil fertility attributes measured with an on-line visible and near-infrared spectroscopy were fused with Sentinel-2 retrieved normalized difference vegetation index (VNIRS-SSS). In-row seed-to-seed distances were varied by 29, 31, 36, 40, 43 cm for Dal, and 25, 31, 36, 43, 47 cm for Bottelare following the prescription rule of sowing more seeds to the more fertile zones and vice-versa, whereas 36 cm seeding interval was applied for the control URS treatment. Yield analysis indicated that the SSS improved tuber yields, saved seed costs, and accordingly increased net economic return compared to the URS. The highest yield was harvested in Dal field for VNIRS-SSS (59.13 t/ha), followed by EMI-SSS (58.39 t/ha) and URS (56.16 t/ha). The VNIRS-SSS also produced higher yield (16.75 t/ha) at Bottelare site than EMI-SSS (16.49 t/ha) and URS (13.70 t/ha). The net profit of the SSS treatments was 5.35 to 56.0% higher than that of the URS treatment. The VNIRS-SSS treatment produced the highest net return (380.27 €/ha) for Dal, while EMI-SSS resulted in the highest net return (447.67 €/ha) for Bottelare. Therefore, regardless of the type of data/sensor used, map-based SSS is recommended for improving the production of consumption potato and increasing net economic margin.

Finding Suitable Transect Spacing and Sampling Designs for Accurate Soil ECa Mapping from EM38-MK2

Finding an ideal sampling design is a crucial stage in detailed soil mapping to assure reasonable accuracy of resulting soil property maps. This study aimed to evaluate the influence of sampling designs and sample sizes on the quality of soil apparent electrical conductivity (ECa) maps from an electromagnetic sensor survey. Twenty-six (26) parallel transects were gathered in a 72-ha plot in Southeastern Brazil. Soil ECa measurements using an on-the-go electromagnetic induction sensor were taken every second using sensor vertical orientation. Two approaches were used to reduce the sample size and simulate kriging interpolations of soil ECa. Firstly, the number of transect lines was reduced by increasing the distance between them; thus, 26 transects with 40 m spacing; 13 with 80 m; 7 with 150 m; and 4 with 300 m. Secondly, random point selection and Douglas-Peucker algorithms were used to derive four reduced datasets by removing 25, 50, 75, and 95% of the points from the ECa survey dataset. Soil ECa was interpolated at 5 m output spatial resolution using ordinary kriging and the four datasets from each simulation (a total of twelve datasets). Map uncertainty was assessed by root mean square error and mean error metrics from 400 random samples previously selected for external map validation. Maps were evaluated on their uncertainty and spatial structure of variation. The transect elimination approach showed that maps produced with transect spacing up to 150 m could preserve the spatial structure of ECa variations. Douglas-Peucker results showed lower nugget values than random point simulations for all selected sample densities, except for a 95% point reduction. The soil ECa maps derived from the 75% reduced dataset (by random sampling or Douglas-Peucker) or from 13 transect lines (80 m spacing) showed reasonable accuracy (RMSE of validation circa 0.7) relative to the map interpolated from all survey points (RMSE of 0.5), suggesting that transect spacing of 80 m and reading intervals greater than one second can be used for improving the efficiency of on-the-go soil ECa surveys.

Mapping of Agricultural Subsurface Drainage Systems Using a Frequency-Domain Ground Penetrating Radar and Evaluating Its Performance Using a Single-Frequency Multi-Receiver Electromagnetic Induction Instrument.

Subsurface drainage systems are commonly used to remove surplus water from the soil profile of a poorly drained farmland. Traditional methods for drainage mapping involve the use of tile probes and trenching equipment that are time-consuming, labor-intensive, and invasive, thereby entailing an inherent risk of damaging the drainpipes. Effective and efficient methods are needed in order to map the buried drain lines: (1) to comprehend the processes of leaching and offsite release of nutrients and pesticides and (2) for the installation of a new set of drain lines between the old ones to enhance the soil water removal. Non-invasive geophysical soil sensors provide a potential alternative solution. Previous research has mainly showcased the use of time-domain ground penetrating radar, with variable success, depending on local soil and hydrological conditions and the central frequency of the specific equipment used. The objectives of this study were: (1) to test the use of a stepped-frequency continuous wave three-dimensional ground penetrating radar (3D-GPR) with a wide antenna array for subsurface drainage mapping and (2) to evaluate its performance with the use of a single-frequency multi-receiver electromagnetic induction (EMI) sensor in-combination. This sensor combination was evaluated on twelve different study sites with various soil types with textures ranging from sand to clay till. While the 3D-GPR showed a high success rate in finding the drainpipes at five sites (sandy, sandy loam, loamy sand, and organic topsoils), the results at the other seven sites were less successful due to the limited penetration depth of the 3D-GPR signal. The results suggest that the electrical conductivity estimates produced by the inversion of apparent electrical conductivity data measured by the EMI sensor could be a useful proxy for explaining the success achieved by the 3D-GPR in finding the drain lines.

Investigation of Hybrid Locomotive Robot for Anti-Personnel Mine Detection

Most of landmine detection robots proposed so far have been strongly restricted from locomotion inside the mine field because they cannot cross over the mine. So we have proposed a mine detection robot with hybrid locomotion, which can enter inside the minefield with low ground surface contact, which can cross over the mine instead of changing its path and scan landmines directly using Electro Magnetic Induction sensor. The hybrid locomotion proposed in the robot uses the frame walking technique and the conventional wheeled locomotion. The robot switches over the locomotion mechanism from wheeled to leg when mine is detected and vice versa with a lead screw mechanism. The leg locomotion is achieved by frame walking technique where the two frames translate with the help of lead screw mechanism. A purpose of adopting this combination is to evade anti-personnel landmines which are relatively smaller in comparison to their anti-tank landmine counterparts. The robot initially starts in wheeled mode and upon detection of metal, pulls in the frame walking algorithm. The robot also deploys an obstacle avoidance algorithm when working in wheel mode.

Speed Control of Peanut Planting System

This paper is aimed to control the speed of peanut planting system. The system introduces a control mechanism to drop the seeds at a particular position with specified distance, to achieve desired seed rate within the row, uniform seed spacing and alarm system. The overall system includes motion sensor, proximity induction sensor, two servo motors, three DC motors and alarm system. These parts are controlled by Arduino Mega 2560 which is the heart of the system. The battery 12V, 5AH Lead Acid Battery is used for the whole system. So, the wheel motors of machine are controlled by PWM DC motor speed controller separately. Another DC motor is used to stir the seeds within the seed storage tank. When there is no seed to detect within the seed storage tank, it sends the signal to the Arduino and indicates the alarm. To get equal seed spacing or seed to seed distance, proximity induction sensor is used. Servo motors are used for precise control of seed rating. The paper presents calculation of gear ratio, desired motor RPM, PWM out level are also described completely.

Twin loop induction sensor for detection Partial discharge

Partial-discharge is a symptom of high voltage insulation aging, which is a small voltage pulse with high frequency and superposition with high voltage sources that have low frequencies. To find out the existence of this signal, it needs a reliable measurement technique to avoid misinterpretation. This paper presents a technique for measuring partial discharge with an induction method. The sensor used is circular twin loops. The first loop passes through a partial discharge signal, and the second induction receiver produces an induced voltage signal. Various sizes of loop diameters are designed with dimensions 3.2, 4.7, 8.9, and 11.4 cm to look for sensor sensitivity. The performance sensor is analyzed by reading the sensitivity test to the input given with 50-ohm oscilloscope impedance. From the measurement results, the higher the diameter of the sensor loop has good sensitivity.

ИНДУКЦИОННЫЙ МЕТОД ИССЛЕДОВАНИЯ ПАРАМЕТРОВ ДИСПЕРСНЫХ ФЕРРОМАГНЕТИКОВ

The purpose of investigations consists in the definition of the dependence of induction electromotive force (EF) upon magnetic and inertial properties of ferromagnetic particles of magneto-vibrating layer, and also upon induction gradient, frequency of a variable component and induction of a direct component of an electromagnetic field. 
 There is offered an induction method for investigations of dispersion ferromagnetic parameters. A principle of operation and basic elements of the design of an experimental plant which allows investigating the impact of the parameters of electromagnetic fields of different topology upon magnetic-vibrating layer characteristics is developed.
 Two electromagnets with the common inter-pole area are a basic element of the experimental plant realizing the formation of the magneto-vibrating layer of high-dispersion powders. Electromagnet poles were located in such a way that force lines of constant and alternating magnetic fields were mutually perpendicular. A cluster, in the course of its motion relative to coils of an induction sensor, guides an EF in it, a value of which depends upon a magnetic moment of the cluster, speed, amplitude and frequency of its motion. There are obtained analytical expressions for the EF guided in an induction sensor moving by a magnetic dipole. 
 It is shown that a basic contribution to the induction EF is carried out by a magnetic dipole at oscillatory-translation; at changing parameters of an electro-magnetic field changes a motion character of powder material particles. 
 It is proved that the experimental estimate of kinematic characteristics of powder particles in a magnetic-oscillating layer is possible through an induction method.

Development of practical tools faraday effects on magnetic materials

This research aims to develop practical tools faraday effects that can be used as a medium for learning physics subjects in magnetic materials. The development method used is the Research and Development (R&D) method with the ADDIE model approach. The stages of this research are to Analyze, Design, Development, Implementation, and Evaluation. The tools and materials used are magnetic field sensors, 400 winding solenoids as induction sensors for test materials, Power Supply, 500x magnification USB microscope, CSV as data storage from sensors, Delphi 2007 as a hysteresis curve viewer. Product evaluation in the form of validation was carried out using an instrument in the form of a questionnaire filled by media experts with an average score of 93.94% so that it was in the excellent category and material experts with an average score of 86.05% so that it was in the very good category. The expected results of this study are. The results of the assessment of the effectiveness of the Faraday effect practicum tool, an N-gain of 0.67 was obtained that the average pretest was 48.0 and posttest 83.0. Based on the data above, this research shows that the development of the Faraday effect practicum tool is suitable for use as a learning medium.

Метод неразрушающего контроля на основе спин-поляризационного эффекта

This paper proposes a novel nondestructive testing method for electrically conductive objects. It is based on applying a fundamentally new physical effect which has not been used before in nondestructive testing systems. The method utilizes spin polarization phenomena that occur when free electrons of conductive materials are exposed to an alternating electric field. Researchers experimented with wire and cable conductors. A tested cable was moving longitudinally and exposed to an alternating electric field, which excited a waveform process, i.e. the polarization of spin magnetic moments of free electrons. An induction sensor registered this process and generated a control signal: induction EMF. Its parameters were compared against that of a reference signal obtained in advance in the same way utilizing spin polarization phenomena. Parametric deviations were then used to detect and classify conductor defects. The paper describes how to generate a reference signal appropriate for the objectives of testing. The developed method enables nondestructive testing of objects made of any conductive para- and diamagnetic materials, while it accuracy and reliability are not affected by the magnitude or evenness of the object movement speed, nor by vibrations or transverse oscillations against the physical field source or the induction sensor.

Применение индукционных датчиков в исследованиях быстропротекающих процессов

When testing on a rocket track, one of the most difficult problems is the system for controlling and launching pyrotechnic devices at a given coordinate. The way of start-up and device for its implementation, is intended to provide actuation of pyrotechnic means during acceleration of the rocket trains on the rails rocket catapult track to hypersonic speeds with ejection test subject in free flight. The method is based on the principle of generating current pulses for triggering pyrotechnic devices of moving stages of a rocket train using induction sensors. The same principle makes it possible to implement a non-contact method for starting recording systems and a device for measuring the average speed of a thrown object in continuous media. The method is based on the principle of generating triggering signals (rectangular pulses of positive polarity) for starting the recording equipment with synchronization of the launch along the path in a given coordinate and measuring the speed of the object being thrown at the time of its passage through the measuring section. The methods of starting recording systems and the results obtained as a result of hydrodynamic and terradynamic experiments are presented.

3D mapping of soil organic carbon content and soil moisture with multiple geophysical sensors and machine learning

AbstractSoil organic C (SOC) and soil moisture (SM) affect the agricultural productivity of soils. For sustainable food production, knowledge of the horizontal as well as vertical variability of SOC and SM at field scale is crucial. Machine learning models using depth‐related data from multiple electromagnetic induction (EMI) sensors and a gamma‐ray spectrometer can provide insights into this variability of SOC and SM. In this work, we applied weighted conditioned Latin hypercube sampling to calculate 25 representative soil profile locations based on geophysical measurements on the surveyed agricultural field, for sampling and modeling. Ten additional random profiles were used for independent model validation. Soil samples were taken from four equal depth increments of 15 cm each. These were used to approximate polynomial and exponential functions to reproduce the vertical trends of SOC and SM as soil depth functions. We modeled the function coefficients of the soil depth functions spatially with Cubist and random forests with the geophysical measurements as environmental covariates. The spatial prediction of the depth functions provides three‐dimensional (3D) maps of the field scale. The main findings are (a) the 3D models of SOC and SM had low errors; (b) the polynomial function provided better results than the exponential function, as the vertical trends of SOC and SM did not decrease uniformly; and (c) the spatial prediction of SOC and SM with Cubist provided slightly lower error than with random forests. Hence, we recommend modeling the second‐degree polynomial with Cubist for 3D prediction of SOC and SM at field scale.

Indukcione zavojnice za merenje kvazistacionarnih magnetnih polja niskog intenziteta

Short air core induction coils with a large radius and a large number of turns can be successfully used as induction sensors for detecting low-intensity quasistationary magnetic fields, such as magnetic fields of ships. The application of these sensors is presented in detail, and then a practical methodology for determining all the necessary parameters of the sensor is proposed. The sensitivity of sensors with actual design parameters is determined and inductance is calculated in several ways. The practical results of ship's magnetism measurement and the calculation of all parameters of the coil are presented. A comparative analysis of all results was performed and the observed deviations were thoroughly commented on.

Velocity measurement method of moving object with a magnetic field source based on the measurement of the difference signal of two induction sensors

The article describes a new method for measuring the velocity of movement of an object with a magnetic field source. A moving plasma piston in a channel of a magnetoplasma accelerator, which is essentially a moving conductor with current, is considered as an example of such an object. The method is based on the measurement of the difference signal of two induction sensors. The advantage of the method is the presence of a linear dependence between the primary measuring signal (difference signal) and the final informative parameter (the value of the velocity of movement of the conductor with current). The task of simplifying the velocity measurement is solved at the expense of this advantage.

Mapping an Agricultural Field Experiment by Electromagnetic Induction and Ground Penetrating Radar to Improve Soil Water Content Estimation

A growing interest in proximal sensing technologies for estimating soil water content (SWC) will be highlighted. On this matter the objectives of this study were: (1) to use both the combined electromagnetic induction (EMI) sensor and Ground Penetrating Radar (GPR) to characterize an innovative field experiment located in southern Italy, in which different agricultural practices are tested, including a soil hydraulic arrangement; (2) to implement a geostatistical approach in order to merge different geophysical sensor data as auxiliary variables for SWC estimation. The multi-sensor recorded data were: (1) SWC data measured by gravimetric method; (2) Differential Global Positioning System height; (3) apparent electrical conductivity measured by an EMI sensor; (4) depths of soil discontinuities individuated by GPR radargrams interpretation; and (5) amplitude of GPR signal data at two different frequencies. Geostatistical techniques were used both to map all variables and improve the SWC estimation. The findings of this research indicate that: (1) the GPR radargrams identified four reflection events as a consequence of interfaces; (2) the EMI and GPR mapping provided identification of areas with high potential for water stagnation; and (3) the outputs of geophysical sensors can be effectively used as auxiliary tools to supplement the sampling of the target variable and to improve water content estimation.

High-Frequency Electromagnetic Induction (HFEMI) Sensor Results from IED Constituent Parts

The detection and classification of subsurface improvised explosive devices (IEDs) remains one of the most pressing military and civilian problems worldwide. These IEDs are often intentionally made with either very small metallic parts or less-conducting parts in order to evade low-frequency electromagnetic induction (EMI) sensors, or metal detectors, which operate at frequencies of 50 kHz or less. Recently, high-frequency electromagnetic induction (HFEMI), which extends the established EMI frequency range above 50 kHz to 20 MHz and bridges the gap between EMI and ground-penetrating radar frequencies, has shown promising results related to detecting and identifying IEDs. In this higher frequency range, less-conductive targets display signature inphase and quadrature responses similar to higher conducting targets in the LFEMI range. IED constituent parts, such as carbon rods, small pressure plates, conductivity voids, low metal content mines, and short wires respond to HFEMI but not to traditional low-frequency EMI (LFEMI). Results from recent testing over mock-ups of less-conductive IEDs or their components show distinctive HFEMI responses, suggesting that this new sensing realm could augment the detection and discrimination capability of established EMI technology. In this paper, we present results of using the HFEMI sensor over IED-like targets at the Fort AP Hill test site. We show that results agree with numerical modeling thus providing motives to incorporate sensing at these frequencies into traditional EMI and/or GPR-based sensors.

Wideband Models for the Electromagnetic Induction Signatures of Thin Conducting Shells

Wideband electromagnetic induction sensors have been shown to be more effective than traditional metal detectors at identifying metallic targets of interest when buried near abundant metallic clutter. A promising strategy for performing target identification using wideband data relies on characterizing the target response using a magnetic polarizability tensor (MPT) that is a function of frequency. In this paper, a surface integral method is presented for deriving the MPT in singularity expansion form using a modal decomposition. The method is verified by comparing the singularity expansion for a spherical shell to a derived analytical solution. The expansion coefficients for cylindrical tubes, of various aspect ratios, are compared to experimental results, showing good agreement. Finally, expansion coefficients are given for a disk and are compared to other numerical results.

Assessing the Effectiveness of Variable-Rate Drip Irrigation on Water Use Efficiency in a Vineyard in Northern Italy

Although many studies in the literature illustrate the numerous devices and methodologies nowadays existing for assessing the spatial variability within agricultural fields, and indicate the potential for variable-rate irrigation (VRI) in vineyards, only very few works deal with the implementation of VRI systems to manage such heterogeneity, and these studies are usually conducted in experimental fields for research aims. In this study, a VR drip irrigation system was designed for a 1-ha productive vineyard in Northern Italy and managed during the agricultural season 2018, to demonstrate feasibility and effectiveness of a water supply differentiated according to the spatial variability detected in field. Electrical resistivity maps obtained by means of an electro-magnetic induction sensor were used to detect four homogeneous zones with similar soil properties. In each zone, a soil profile was opened, and soil samples were taken and analyzed in laboratory. Two irrigation management zones (MZs) were identified by grouping homogeneous zones on the basis of their hydrological properties, and an irrigation prescription map was built consistently with the total available water (TAW) content in the root zone of the two MZs. The designed drip irrigation system consisted of three independent sectors: the first two supplied water to the two MZs, while the third sector (reference sector) was managed following the farmer’s habits. During the season, irrigation in the first two sectors was fine-tuned using information provided by soil moisture probes installed in each sector. Results showed a reduction of water use by 18% compared to the ‘reference’ sector without losses in yield and product quality, and a grape’s maturation more homogeneous in time.