Electrical Conductivity Sensor Research Articles

Monitoring nitrogen leaching under different fertiliser applications during the early growth stage of sugarcane using GS3 sensors: a case study on Negros Island, Philippines

ABSTRACT Nitrogen (N) is normally applied twice during sugarcane cultivation on Negros Island in the Philippines. As the first application is carried out during the early growth stage, there is a high possibility that N is not absorbed sufficiently by the sugarcane and a large amount of N may be leached with percolating water. To investigate this leaching, we monitored the vertical movement of soil water and soil solutes using GS3 dielectric moisture and electrical conductivity (EC) sensors in a sugarcane field on Negros Island. The monitoring was conducted after the first N application at different application rates (50% or 100% of the recommended rate) and timings (immediately or 30 days after planting [DAP]). The EC values increased when 100%-N was applied immediately after planting, indicating that N leached into the deeper soil layer. The monitoring results suggest that the applied N did not remain in the root zone (due to leaching) and was not replenished until the second application, when the absorption ability of the sugarcane was high. Conversely, when 100%-N was applied at 30 DAP, the applied N remained in the root zone until the second application. When 50%-N was applied at 30 DAP, the increase in EC was small compared to the 100%-N application. These results indicate that applying N immediately after planting at the recommended rate led to an insufficient nutrient supply for the sugarcane, as well as the loss of N fertiliser via leaching.

Automatic hydroponic nutrient mixing for hydroponic NFT and fertigation

This paper aims to create hydroponic nutrient mixing system automatically for circulation hydroponic system like NFT (Nutrient Film Technique) and for non-circulation hydroponic system such as drip irrigation system. System continuously sense nutrient concentration and pH level with EC (Electrical Conductivity) sensor and pH sensor. This data will process by ESP32 Wi-Fi microcontroller for monitoring and control dosing pump to maintain nutrient solution EC and pH with the predefined target. In non-circulated hydroponic, nutrition and water will flow into the irrigation system, to control humidity level in plant media, system use soil moisture level sensor. System use IoT cloud Blynk for easy user control and monitoring, user can use application in their smartphone. Test result shows system can increase the EC value from current condition 0.7 to target 3 within ±9 minutes and can maintain the EC value.

Mastitis Detection System in Dairy Cow Milk based on Fuzzy Inference System using Electrical Conductivity and Power of Hydrogen Sensor Value

This study build a system for screening method to detect mastitis in dairy cow milk using Electrical Conductivity (EC) and Power of Hydrogen (pH) sensor. The value of EC and pH sensor is analyze using fuzzy logic to clarify the truth value between it. Mastitis in cows can cause loss and decrease milk production and quality in the dairy farmer industry. Currently, detecting mastitis in cow’s milk still done manually by looking at the color change of the milk and analyzing the cow behavior. This paper has designed a mastitis detection system using the Mamdani type fuzzy inference system and the final result will be displayed on an Android-based smartphone. From the test result, it was found that the system has 79.2% detection accuracy value. This system is suitable for alternative screening method that used to detect mastitis in dairy cow milk.

SPATIAL VARIABILITY OF SOIL APPARENT ELECTRICAL CONDUCTIVITY - EFFECT OF THE NUMBER OF SUBSAMPLES

Soil apparent electrical conductivity (ECa) sensors have been used to detect spatial variability because they correlate with soil attributes. Studies with soil attributes have shown that the number of subsamples and sampling points influences mapping. However, there are no studies that investigated the influence of sampling or subsampling density on ECa maps. Therefore, this study verified the influence of ECa readings per sample point on the semivariance and kriging analysis. The data were collected from an area (2.5 ha) of coffee plants. One hundred sampling points were measured considering 20 readings each. 1, 5, 10, 15, and 20 sample point readings were tested. The influence of the number of readings per sampling point on the ECa mapping was determined using linear regression analysis at a significance level of 5%. The results obtained showed that ECa readings per sampling point significantly influence ECa maps. In addition, they demonstrated that reducing the number of readings per sampling point increases prediction errors by kriging. Thus, ECa maps determined with the highest readings per sampling point were mostly accurate.

A Low-Cost Water Depth and Electrical Conductivity Sensor for Detecting Inputs into Urban Stormwater Networks.

High-resolution data collection of the urban stormwater network is crucial for future asset management and illicit discharge detection, but often too expensive as sensors and ongoing frequent maintenance works are not affordable. We developed an integrated water depth, electrical conductivity (EC), and temperature sensor that is inexpensive (USD 25), low power, and easily implemented in urban drainage networks. Our low-cost sensor reliably measures the rate-of-change of water level without any re-calibration by comparing with industry-standard instruments such as HACH and HORIBA’s probes. To overcome the observed drift of level sensors, we developed an automated re-calibration approach, which significantly improved its accuracy. For applications like monitoring stormwater drains, such an approach will make higher-resolution sensing feasible from the budget control considerations, since the regular sensor re-calibration will no longer be required. For other applications like monitoring wetlands or wastewater networks, a manual re-calibration every two weeks is required to limit the sensor’s inaccuracies to ±10 mm. Apart from only being used as a calibrator for the level sensor, the conductivity sensor in this study adequately monitored EC between 0 and 10 mS/cm with a 17% relative uncertainty, which is sufficient for stormwater monitoring, especially for real-time detection of poor stormwater quality inputs. Overall, our proposed sensor can be rapidly and densely deployed in the urban drainage network for revolutionised high-density monitoring that cannot be achieved before with high-end loggers and sensors.

Assessment of soil salinity indexes using electrical conductivity sensors

The salinity tolerance of plants can be improved by efficient irrigation management and salt flushing, which require a continuous and precise knowledge of the salinity in the soil or substrate. Soil sensors that measure electrical conductivity play an essential role in monitoring soil salinity. However, the correct interpretation of salinity measurements using soil sensors depends on developing appropriate salinity indexes. This work studied the potential of several salinity indexes based on the bulk EC (ECb) directly measured by soil sensors, and on pore water EC (ECw) estimated by the Hilhorst model (ECwHI). The methodology used in the experiments is based on the simultaneous use of scales and sensors, which allowed the automatic monitoring of the real salinity levels of the substrate, and the conductivity measurements made with the soil sensor. Regression studies were carried out to know how well the proposed salinity indexes explain real salinity. In general, all the indexes were suitable for estimating the relative changes in substrate salinity, as long as they met certain requirements. For example, ECwHI was seen to be a reliable salinity index when substrate moisture was high and constant. However, there was no such requirement when the ECwHI was corrected according to the current substrate water content, or when the salinity index was calculated as the average of the ECwHI values between two successive irrigation events. ECb was an efficient salinity indicator as long as the moisture content was constant, although its accuracy increased at a high moisture level. The findings led us to propose a new salinity index calculated with the slopes of the linear section of the quadratic moisture adjustment, which avoids the need for the substrate moisture content to be constant.

Rekayasa Digitalisasi Pertanian Hidroponik NFT dengan Model Kendali Suhu, pH dan Electrical Conductivity (EC)

Madura, which is nicknamed the island of salt, began to develop hydroponics, especially for the fulfillment of vegetables. So far, hydroponic practitioners have always checked the nutrients on their hydroponic plants twice every day to ensure that the plant's nutritional needs are met, besides that the temperature and pH of the water must also be maintained according to plant needs so that plants can grow and develop properly as expected. Controlling the temperature and pH of the water as well as the nutritional needs that are carried out routinely every day by manual method on hydroponic growing media is considered a hassle. Not everyone understands the technical details of care for the ideal conditions of plants that must be maintained, especially for hydroponic beginners. It is necessary to digitize agriculture, through controlling the plant media automatically based on temperature settings, the measurement of nutritional needs and the pH adjusting the types of vegetables planted. Temperature conditions are monitored using a DS18B20 waterproof sensor with a thermoelectric cooler as a temperature stabilizer actuator in ideal conditions. Meanwhile, the nutritional requirements are calculated based on the type of plant, the reading of potential hydrogen (pH) levels by the pH sensor and the electrical conductivity (EC) value by the EC and TDS sensors are continuously responded by the peristaltic pump to determine the amount of solution and ideal nutritional requirements for plant. The control method (PID) which is implemented in active / non-peristaltic pump activities to control temperature, pH of the solution and nutritional needs based on the EC value of the solution is more precise and only a few times an error with an error value ranging from 1 - 2 ml.

Development of polyaniline for sensor applications: A review

This review is focusing on the uses of polyaniline as conductive sensors over the past decade and especially for biosensors to be within easy reach. The effort of conducting polymers has been on modern reviewing literature that addressing use as a sensor. In addition, the gradual development in the literature on the evolution of polyaniline as electrical conductivity methods and sensor in the chemical or biological field according to time sequence. Numbers of potential applications and different possible uses have shown promising application for polyaniline polymers.

Fault sealing and caprock integrity for CO<sub>2</sub> storage: an in situ injection experiment

Abstract. The success of geological carbon storage depends on the assurance of permanent containment for injected carbon dioxide (CO2) in the storage formation at depth. One of the critical elements of the safekeeping of CO2 is the sealing capacity of the caprock overlying the storage formation despite faults and/or fractures, which may occur in it. In this work, we present an ongoing injection experiment performed in a fault hosted in clay at the Mont Terri underground rock laboratory (NW Switzerland). The experiment aims to improve our understanding of the main physical and chemical mechanisms controlling (i) the migration of CO2 through a fault damage zone, (ii) the interaction of the CO2 with the neighboring intact rock, and (iii) the impact of the injection on the transmissivity in the fault. To this end, we inject CO2-saturated saline water in the top of a 3 m thick fault in the Opalinus Clay, a clay formation that is a good analog of common caprock for CO2 storage at depth. The mobility of the CO2 within the fault is studied at the decameter scale by using a comprehensive monitoring system. Our experiment aims to close the knowledge gap between laboratory and reservoir scales. Therefore, an important aspect of the experiment is the decameter scale and the prolonged duration of observations over many months. We collect observations and data from a wide range of monitoring systems, such as a seismic network, pressure temperature and electrical conductivity sensors, fiber optics, extensometers, and an in situ mass spectrometer for dissolved gas monitoring. The observations are complemented by laboratory data on collected fluids and rock samples. Here we show the details of the experimental concept and installed instrumentation, as well as the first results of the preliminary characterization. An analysis of borehole logging allows for identifying potential hydraulic transmissive structures within the fault zone. A preliminary analysis of the injection tests helped estimate the transmissivity of such structures within the fault zone and the pressure required to mechanically open such features. The preliminary tests did not record any induced microseismic events. Active seismic tomography enabled sharp imaging the fault zone.

Development and Evaluation of a Variable-Rate Irrigation Management Method in the Mississippi Delta

HighlightsWe developed and evaluated a variable-rate irrigation (VRI) management method for five crop years in the Mississippi Delta.VRI management significantly reduced irrigation water use in comparison with uniform-rate irrigation (URI). There was no significant difference in grain yield and irrigation water productivity between VRI and URI management.Soil apparent electrical conductivity (ECa) was used to delineate irrigation management zones and generate VRI prescriptions.Sensor-measured soil water content was used in irrigation scheduling.Abstract. Variable-rate irrigation (VRI) allows producers to site-specifically apply irrigation water at variable rates within a field to account for the temporal and spatial variability in soil and plant characteristics. Developing practical VRI methods and documenting the benefits of VRI application are critical to accelerate the adoption of VRI technologies. Using apparent soil electrical conductivity (ECa) and soil moisture sensors, a VRI method was developed and evaluated with corn and soybean for five crop years in the Mississippi Delta. Soil ECa of the study fields was mapped and used to delineate VRI management zones and create VRI prescriptions. Irrigation was scheduled using soil volumetric water content measured by soil moisture sensors. A center pivot VRI system was employed to deliver irrigation water according to the VRI prescription. Grain yield, irrigation water use, and irrigation water productivity in the VRI treatment were determined and compared with that in a uniform-rate irrigation (URI) treatment. Results showed that the grain yield and irrigation water productivity between the VRI and URI treatments were not statistically different with both corn and soybean crops. The VRI management significantly reduced the amount of irrigation water by 22% in corn and by 11% in soybean (p = 0.05). Adoption of VRI management could improve irrigation water use efficiency in the Mississippi Delta. Keywords: Soil electrical conductivity, Soil moisture sensor, Variable rate irrigation, Water management.

Comparative Analysis on Facility, Environment, Growth of Cut Flower, and Management Performance in Conventional and Smart Farm of <i>Chrysanthemum</i> ‘Baekma’

We analyzed and compared the facility status, cultivation environment, growth of flowers, and management performance of a conventional farm and a smart farm in which Chrysanthemum ‘Baekma’ was grown. The conventional farm consisted of cultivation with soil culture in a plastic film greenhouse, whereas the smart farm consisted of hydroponic cultivation in a glass greenhouse. The smart farm was equipped with sensors for measuring solar radiation, temperature, humidity, CO2, wind speed, rainfall, and pH and electrical conductivity (EC) of the nutrient solution, and was managed in real time using computers and mobile phone applications. In contrast, the conventional farm had neither sensors for environmental measurement nor pH and EC sensors for fertigation, and all systems were operated manually. The day and night temperatures in the plastic film house of the conventional farm were lower than the optimum growth temperature of Chrysanthemum ‘Baekma’. The soil EC of the conventional farm was found to be high (3.2 dS･m-1) indicating that it was not suitable for the growth of cut flowers, whereas the smart farm was properly managed at 1.1 dS･m-1. With respect to the cultivation method, no soil disinfection was performed at the conventional farm, whereas disinfection using hydrogen peroxide was performed at the smart farm. Although there were no other significant differences in cultivation methods, symptoms of damage by mites were seen at the conventional farm. The plant growth, such as length of cut flowers, flower diameter, fresh weight, and chlorophyll content were improved in the smart farm compared with the conventional farm. In terms of management performance (based on an area of 1,000 m2), the net income was -419,000 won for the conventional farm and 4,484,000 won for the smart farm, and the yield and sales price were 22% and 52% higher in smart farm than in the conventional farm, respectively. The results of this study indicate that the differences in the plant growth as well as management performance can be attributed to precise plant growth regulation by the automated facilities at the smart farm.

Portable Soil Electrical Conductivity Sensor System Based on Electromagnetic Pulsed Eddy Current method

Soil salinization is one of the major environmental geological concerns around the world. The rapid survey of soil conductivity is urgent to reflect the salinization degree in time, while current methods rely on lab-test or electronic probe-based ones, which are not efficient on saving cost and improving efficiency. In this paper, a new electrical conductivity sensor based on electromagnetic pulsed eddy current strategy is proposed to meet the purpose of rapid and efficient survey of soil conductivity. Relevant software was also designed and tested. To facilitate the in-field test, a portable system was constructed.

Effect of asymmetric airflow on liquid film behavior and emergency core coolant bypass in the downcomer geometry of a nuclear reactor pressure vessel

In this study, experimental work was carried out using a 1/10 reduced-scale downcomer of a nuclear reactor pressure vessel to examine the liquid film behavior under emergency core coolant (ECC) bypass conditions. It is caused by the interaction between the transverse gas flow and the falling liquid film. The experiments were conducted considering the asymmetric gas velocity inside the downcomer. An air–water mixture was used as the working fluid in the experiment, forming a complex liquid film flow in the annular test section of the downcomer. To measure the local liquid film thickness, an electrical conductance sensor fabricated on a flexible printed circuit board was applied. The effect of the asymmetric airflow on the liquid film behavior was investigated using the liquid film thickness measurements. Results showed that the asymmetry influences the distribution of the liquid film; the larger the asymmetry, the closer is the liquid film is to the break with the same gas outlet velocity. It influences the trend of the ECC bypass fraction with respect to the gas velocity. The present study provides detailed understanding of the ECC bypass phenomenon under asymmetric airflow conditions; this enables determining how the liquid film behavior is changed by the gas flow and how it affects the ECC bypass.

Operational monitoring and forecasting of wave run-up on seawalls

In this work, a wave run-up monitoring system and a model for forecasting the wave run-up height on a seawall were developed. Electrical conductivity sensors were installed on the seaward slopes of seawalls to measure the wave run-up heights. The general packet radio service protocol was used to transmit the measured data in real time to the desired remote location. The Princeton Ocean Model and WAVEWATCH III were used to predict the water levels and ocean waves, respectively, by using the available wind fields. The empirical formulas recommended in the Coastal Engineering Manual (2011) and EurOtop (2018) were adopted to estimate the run-up height. The wave run-up heights were forecasted 72 h in advance and were renewed at 6-h intervals as new wind fields became available. The developed monitoring system and forecasting model were combined for operational monitoring and forecasting of wave run-up on seawalls. The wave run-up monitoring system was set up at three seawalls along the southwestern coast of Taiwan from 2013 to 2016. Consistency between the forecasted and measured wave run-up heights during typhoon periods demonstrated the feasibility of using the proposed method for monitoring and forecasting wave run-up heights. Furthermore, the multi-model ensemble approach was adopted to improve the unsatisfactory run-up forecasting performance during typhoon periods, and the forecasted run-up heights were eventually presented as a band with upper and lower limits as opposed to single values. The forecast results can be used to provide advance warning of possible wave overtopping and associated coastal flooding during typhoon periods.

Farklı Buğday Çeşitlerinde Bitki Büyüme İndisi İle Toprak Elektriksel İletkenlik Değerleri Arasındaki İlişki

Araştırma, Ankara Üniversitesine bağlı Haymana Araştırma ve Uygulama çiftliğinde gerçekleştirilmiştir. Çalışmada üç farklı buğday çeşidi (Kırgız-95, Kırkpınar-79, Svevo) kullanılmıştır. Araştırmanın amacı toprağın elektriksel iletkenlik değerleri (EC, mS m-1) ile bitki büyüme indisi (BBİ) veya NDVI olarak tanımlanan parametrelerin belirlenerek, bu parametreler arasındaki ilişkinin belirlenmesidir. Araştırmada; EM38, elektriksel iletkenlik sensörü ve GreenSeeker (bitki büyüme indisi tespit sensörü) kullanılmıştır. Elde edilen değerler istatistiksel olarak değerlendirilerek (regresyon analizi) iki parametre arasındaki ilişki belirlenmiştir. Araştırma sonucunda, toprağın elektriksel iletkenlik değerleri ile bitki büyüme indis değerleri arasındaki ilişkiler negatif yönde (R2) sırasıyla Kırgız-95 çeşidi için 0,7718, Kırkpınar-79 çeşidi için 0,7675 ve Svevo çeşidi için 0,7807 olarak bulunmuştur.

Development of multifunctional polyacrylonitrile/silver nanocomposite films: Antimicrobial activity, catalytic activity, electrical conductivity, UV protection and SERS-active sensor

The formulation of polymer with embedded nanoparticles results in promising nanocomposites and substrates for smart, medical and analytical applications. Nanocomposite polyacrylonitrile (PAN) films containing silver nanoparticles (Ag NPs) were developed to introduce multifunctional film matrix with antimicrobial activity, electrical conductivity, ultraviolet blocking and catalytic activity. In addition, the prepared PAN/Ag NPs nanocomposite films can be applied in the identification of biological molecules using surface enhanced Raman scattering (SERS). PAN/Ag NPs nanocomposites were prepared by reducing Ag+ to Ag0 under microwave irradiation. The reduction process of Ag+ to Ag NPs was performed in-situ within the matrix of polyacrylonitrile fibers dissolved in N, N-dimethylformamide (DMF). Thus, DMF was functioned as a reducing agent for the generation of Ag NPs from silver nitrate (AgNO3) and as a solvent for polyacrylonitrile. The Ag NPs were evaluated Via UV–vis spectrum TEM. The PAN and PAN/Ag NPs nanocomposite were analyzed, by using SEM, EDX, FTIR, XRD, XPS, TGA and DSC. The reaction mechanism for in-situ deposition of Ag NPs onto PAN polymer matrix was also explored. The influence of Ag NPs on multifunctional properties of PAN nanocomposite films such as coloration properties, antimicrobial activity, electrical conductivity property, UV protection activity, SERS and catalytic activity were evaluated. The results displayed that, the PAN/Ag NPs nanocomposites films were exhibited excellent antimicrobial activities against different micro-organisms as well as very good electrical conductivity and UV protection properties. Moreover, the PAN/Ag NPs nanocomposites films were shown highly SERS sensitivity at low concentration as well as high catalytic activity. In straightforward, this simple, fast and inexpensive novel approach will pave the way for a variety of smart medical applications, such as scar-less burn wound healing and biological protective substrates as well as analytical application.

Adaptive Water Sampling Device for Aerial Robots

Water quality monitoring and predicting the changes in water characteristics require the collection of water samples in a timely manner. Water sample collection based on in situ measurable water quality indicators can increase the efficiency and precision of data collection while reducing the cost of laboratory analyses. The objective of this research was to develop an adaptive water sampling device for an aerial robot and demonstrate the accuracy of its functions in laboratory and field conditions. The prototype device consisted of a sensor node with dissolved oxygen, pH, electrical conductivity, temperature, turbidity, and depth sensors, a microcontroller, and a sampler with three cartridges. Activation of water capturing cartridges was based on in situ measurements from the sensor node. The activation mechanism of the prototype device was tested with standard solutions in the laboratory and with autonomous water sampling flights over the 11-ha section of a lake. A total of seven sampling locations were selected based on a grid system. Each cartridge collected 130 mL of water samples at a 3.5 m depth. Mean water quality parameters were measured as 8.47 mg/L of dissolved oxygen, pH of 5.34, 7 µS/cm of electrical conductivity, temperature of 18 °C, and 37 Formazin Nephelometric Unit (FNU) of turbidity. The dissolved oxygen was within allowable limits that were pre-set in the self-activation computer program while the pH, electrical conductivity, and temperature were outside of allowable limits that were specified by Environmental Protection Agency (EPA). Therefore, the activation mechanism of the device was triggered and water samples were collected from all the sampling locations successfully. The adaptive water sampling with Unmanned Aerial Vehicle-assisted water sampling device was proved to be a successful method for water quality evaluation.

Development and Testing of a Low-Cost Portable Apparent Soil Electrical Conductivity Sensor Using a Beaglebone Black

Abstract.The adoption of apparent soil electrical conductivity (soil ECa) sensors has increased in precision agricultural systems, especially in systems pulled by vehicles. This work developed a portable soil sensor for measuring soil ECa that could be used without vehicles in mountainous areas and small farms. The developed system was based on the electrical resistivity method. The system measured the electrical conductivity by applying a square wave signal at frequencies defined by the user. The acquired data were georeferenced using a low-cost global navigation satellite system (GNSS) receiver. The sensor system was developed using a BeagleBone Black, a low-cost single-board computer. A user interface was developed in C++, and a touch screen with a resolution of 800×480 pixels was used to display the results. This interface performed statistical analysis, and the results were used to guide the user to identify more field locations to be sampled to increase mapping accuracy. The system was tested in a coffee plantation located in a mountainous area and in a sugarcane plantation in Minas Gerais, Brazil. The system worked well in mapping the soil ECa. The apparent soil electrical conductivities measured using frequencies of 10, 20, 30, and 40 Hz were highly correlated. In the sugarcane field that had more variation in soil texture, a greater number of soil properties presented a significant correlation with the soil ECa. Keywords: Electrical conductivity, Geostatistics, Precision agriculture, Soil properties, Soil sensing, Spatial variability.

Электромагнитные измерения уровня и проводимости цветных металлов

The paper presents the developed electromagnetic non-invasive level and electrical conductivity sensors for non-ferrous and alkali metals. The influence of the geometry of the installations on the measurement accuracy was experimentally determined. The limits of permissible errors in the positioning of the sensors relative to the analyzed volumes of metals are established.

Heterogeneous Cubic Multidimensional Integrated Circuit for Water and Food Security in Fish Farming Ponds.

Among major food production sectors, world aquaculture shows the highest growth rate, providing more than 50% of the global seafood market. However, water pollution in fish farming ponds is regarded as the leading cause of fish death and financial losses in the market. Here, an Internet of Things system based on a cubic multidimensional integration of circuit (MD-IC) is demonstrated for water and food security applications in fish farming ponds. Both faces of the silicon substrate are used for thin-film-based device fabrication. The devices are interconnected via through-silicon-vias, resulting in a bifacial complementary metal-oxide-semiconductor-compatible electronics system. The demonstrated cubic MD-IC is a complete, small, and lightweight system that can be easily deployed by farmers with no need for specialists. The system integrates on its outer sides simultaneous air and water quality monitoring devices (temperature, electrical conductivity, ammonia, and pH sensors), solar cells for energy-harvesting, and antenna for real-time data-transfer, while data-management circuitry and a solid-state battery are integrated on its internal faces. Microfluidic cooling technology is used for thermal management in the MD-IC. Finally, a biofriendly polymeric encapsulation is used to waterproof the embedded electronics, improve the mechanical robustness, and allow the system to float on the surface of the water.