Automated sensing of hydroponic macronutrients using a computer-controlled system with an array of ion-selective electrodes

Kim, Hak-Jin; Kim, Wonkyung; Roh, Mi-Young; Kang, Chang-Ik; Park, Jong-Min; Sudduth, Kenneth A.

doi:10.1016/j.compag.2013.01.011

Cited by 85 publications

(50 citation statements)

References 21 publications

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“…The system was developed based on a design concept similar to that applied to a test stand prepared in our previous studies (Kim et al, 2006;2007;2011;2013). A flow diagram of the developed system is shown in Figure 1.…”

Section: Development Of An Automated Measurement Systemmentioning

confidence: 99%

“…The sensor array used to measure the samples from water sources was normalized using the two-point normalization method, as described in previous studies (Cho et al, 2015;Jung et al, 2015;Kim et al, 2011;2013). In principle, baseline-corrected electromotive forces (EMFs) are re-calculated by subtracting the baseline EMF from the data from each sensor to achieve a sensitivity adjustment by adjusting the offset so that any potential drift that might occur during continuous measurements can be minimized.…”

Section: Electrode Performance Testsmentioning

confidence: 99%

“…The use of ion-selective electrodes (ISEs) is feasible for real-time monitoring because they can be used to directly in the medium to be tested. Furthermore, ISEs are both compact and low cost (Kim et al, 2006;2007;2011;2013;Mimendia et al, 2010;Tang et al, 2012;Winkler et al, 2004). However, some concerns remain regarding the stability, repeatability, and selectivity of ISEs when continuous immersion of the electrodes in hydroponic solutions is required, such as that in a continuous, on-line system.…”

Section: Introductionmentioning

confidence: 99%

“…However, some concerns remain regarding the stability, repeatability, and selectivity of ISEs when continuous immersion of the electrodes in hydroponic solutions is required, such as that in a continuous, on-line system. The use of computer-based measurement systems, including automatic solution sampling and electrode calibration, would improve the accuracy and precision of solute concentration determination (Kim et al, 2011;2013).…”

Section: Introductionmentioning

confidence: 99%

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An Automated Water Nitrate Monitoring System based on Ion-Selective Electrodes

Cho¹,

Kim²,

Jung³

et al. 2016

Journal of Biosystems Engineering

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Purpose: In-situ water quality monitoring based on ion-selective electrodes (ISEs) is a promising technique because ISEs can be used directly in the medium to be tested, have a compact size, and are inexpensive. However, signal drift can be a major concern with on-line management systems because continuous immersion of the ISEs in water causes electrode degradation, affecting the stability, repeatability, and selectivity over time. In this study, a computer-based nitrate monitoring system including automatic electrode rinsing and calibration was developed to measure the nitrate concentration in water samples in real-time. Methods: The capabilities of two different types of poly(vinyl chloride) membrane-based ISEs, an electrode with a liquid filling and a carbon paste-based solid state electrode, were used in the monitoring system and evaluated on their sensitivities, selectivities, and durabilities. A feasibility test for the continuous detection of nitrate ions in water using the developed system was conducted using water samples obtained from various water sources. Results: Both prepared ISEs were capable of detecting low concentrations of nitrate in solution, i.e., 0.7 mg/L NO3-N. Furthermore, the electrodes have the same order of selectivity for nitrate:, and maintain their sensitivity by > 40 mV/decade over a period of 90 days. Conclusions: The use of an automated ISE-based nitrate measurement system that includes automatic electrode rinsing and two-point normalization proved to be feasible in measuring NO3-N in water samples obtained from different water sources. A one-to-one relationship between the levels of NO3-N measured with the ISEs and standard analytical instruments was obtained.

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Section: Development Of An Automated Measurement Systemmentioning

confidence: 99%

Section: Electrode Performance Testsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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An Automated Water Nitrate Monitoring System based on Ion-Selective Electrodes

Cho¹,

Kim²,

Jung³

et al. 2016

Journal of Biosystems Engineering

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“…Hydroponics, also known as soilless farming, is a method of growing plants using mineral nutrient solutions in water (Kim et al, 2013). In closed hydroponic systems, assessments of plant growth and biomass status provide useful information for crop production and management.…”

Section: Introductionmentioning

confidence: 99%

Image Processing Methods for Measurement of Lettuce Fresh Weight

Park¹,

Han²,

Kim³

2015

Journal of Biosystems Engineering

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Purpose: Machine vision-based image processing methods can be useful for estimating the fresh weight of plants. This study analyzes the ability of two different image processing methods, i.e., morphological and pixel-value analysis methods, to measure the fresh weight of lettuce grown in a closed hydroponic system. Methods: Polynomial calibration models are developed to relate the number of pixels in images of leaf areas determined by the image processing methods to actual fresh weights of lettuce measured with a digital scale. The study analyzes the ability of the machine vision-based calibration models to predict the fresh weights of lettuce. Results: The coefficients of determination (> 0.93) and standard error of prediction (SEP) values (< 5 g) generated by the two developed models imply that the image processing methods could accurately estimate the fresh weight of each lettuce plant during its growing stage. Conclusions: The results demonstrate that the growing status of a lettuce plant can be estimated using leaf images and regression equations. This shows that a machine vision system installed on a plant growing bed can potentially be used to determine optimal harvest timings for efficient plant growth management.

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Auf dem Weg zum Verständnis des Bildungs‐ und OER‐Katalysemechanismus von Hydroxiden durch In situ‐ und Operando‐Techniken

Chen,

Fan,

Zhou

et al. 2023

Angewandte Chemie

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Developing efficient and affordable electrocatalysts for the sluggish oxygen evolution reaction (OER) remains a significant barrier that needs to be overcome for the practical applications of hydrogen production via water electrolysis, transforming CO2 to value‐added chemicals, and metal‐air batteries. Recently, hydroxides have shown promise as electrocatalysts for OER. In situ or operando techniques are particularly indispensable for monitoring the key intermediates together with understanding the reaction process, which is extremely important for revealing the formation/OER catalytic mechanism of hydroxides and preparing cost‐effective electrocatalysts for OER. However, there is a lack of comprehensive discussion on the current status and challenges of studying these mechanisms using in situ or operando techniques, which hinders our ability to identify and address the obstacles present in this field. This review offers an overview of in situ or operando techniques, outlining their capabilities, advantages, and disadvantages. Recent findings related to the formation mechanism and OER catalytic mechanism of hydroxides revealed by in situ or operando techniques are also discussed in detail. Additionally, some current challenges in this field are concluded and appropriate solution strategies are provided.

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Automated sensing of hydroponic macronutrients using a computer-controlled system with an array of ion-selective electrodes

Cited by 85 publications

References 21 publications

An Automated Water Nitrate Monitoring System based on Ion-Selective Electrodes

An Automated Water Nitrate Monitoring System based on Ion-Selective Electrodes

Image Processing Methods for Measurement of Lettuce Fresh Weight

Auf dem Weg zum Verständnis des Bildungs‐ und OER‐Katalysemechanismus von Hydroxiden durch In situ‐ und Operando‐Techniken

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