Internet of Things (IoT) enabled smart nitrate sensor for real- time water quality monitoring

Thesis by publication.Bibliography: pages 125-146.1. Introduction -- 2. Literature review -- 3. Interdigitated sensing and electrochemical impedance spectroscopy -- 4. Temperature sompensation for low concentration nitrate measurement -- 5. Graphene-PDMS sensor for nitrate measurement -- 6. Selectivity of nitrate sensor -- 7. IoT enabled smart sensing system -- 8. Conclusions and future work -- Bibliography.Nitrate-N is a naturally occurring ionic compound that is part of nature's nitrogen cycle. Nitrates-N are readily lost to ground and surface water as a result of intensive agriculture, industrial wastes, disposal of human and animal sewage. The impact of elevated nitrate-N concentrations on water quality has been identified as a critical issue of a healthy environment for the future. Presently, water quality managers follow the traditional measurement systems that involve physically collecting the sampling water from remote sites and testing it in the laboratory. These methods are expensive, require trained people to analyse the data and produce much chemical waste. Therefore, low-cost Ion Imprinted Polymer (IIP) coated impedimetric nitrate-N sensor was developed, and the detection range of nitrate-N was 1-10 (mg/L). The selective IIP material was sensitive to nitrate-N ions in an aqueous medium, and the results are validated through standard UV-spectrometric methods. MEMS (microelectro-mechanical-system) based interdigital sensor and sensing system was also developed to measure nitrate-N, and the range was 0.01 - 0.5 (mg/L). The graphene-based low-cost sensor was also fabricated, and the sensor was characterized to measure nitrate-N in the range of 1-70 (mg/L). Temperature compensation was added for both the sensors (MEMS and Graphene) and WiFi connectivity was provisioned in the system to transfer the measured data in real time. An improved LoRa based sensing system (solar panel and rechargeable battery powered) was developed and trialled in the field successfully which can measure the nitrate-N concentration in real-time and transfer the data to IoT cloud server to overcome the limitations of lab based sensing system.Mode of access: World wide web1 online resource (xxviii, 146 pages) colour illustration

Detection Methodologies for Pathogen and Toxins: A Review

Pathogen and toxin-contaminated foods and beverages are a major source of illnesses, even death, and have a significant economic impact worldwide. Human health is always under a potential threat, including from biological warfare, due to these dangerous pathogens. The agricultural and food production chain consists of many steps such as harvesting, handling, processing, packaging, storage, distribution, preparation, and consumption. Each step is susceptible to threats of environmental contamination or failure to safeguard the processes. The production process can be controlled in the food and agricultural sector, where smart sensors can play a major role, ensuring greater food quality and safety by low cost, fast, reliable, and profitable methods of detection. Techniques for the detection of pathogens and toxins may vary in cost, size, and specificity, speed of response, sensitivity, and precision. Smart sensors can detect, analyse and quantify at molecular levels contents of different biological origin and ensure quality of foods against spiking with pesticides, fertilizers, dioxin, modified organisms, anti-nutrients, allergens, drugs and so on. This paper reviews different methodologies to detect pathogens and toxins in foods and beverages

Application of practical nitrate sensor based on electrochemical impedance spectroscopy

Nitrate is a naturally occurring ionic compound that is part of nature’s nitrogen cycle. Nitrates are readily lost to ground and surface water as a result of intensive agriculture, disposal of human and animal sewage and industrial wastes and the impact of elevated nitrate concentrations on water quality, has been identified as a critical issue facing New Zealand’s future. It is therefore, highly desirable to monitor water quality to facilitate regional councils and central governments to understand trends in concentrations and to develop a healthy water management policy. Presently, water quality managers follow the traditional measurement systems that involve physically sampling water from remote sites and laboratory-based testing. These methods are expensive, require trained people to analyze the data and produce a lot of chemical waste. Due to the time and labor required, surface samples are often only collected once per month and these risks missing significant trends in nitrate loss. Therefore, it is of utmost important to develop low-cost, robust embedded sensor nodes to detect the concentration of individual nutrients like nitrate and nitrite in surface and ground water. The interdigital capacitive sensor has been used to measure the different nitrate concentration. The sensor used to measure also the temperature and humidity of the samples. The results have shown that the sensor has high potential in a different application.28 page(s

Multi-Walled Carbon Nanotubes-Based Sensors for Strain Sensing Applications

The use of multi-walled carbon nanotube (MWCNT)-based sensors for strain–strain applications is showcased in this paper. Extensive use of MWCNTs has been done for the fabrication and implementation of flexible sensors due to their enhanced electrical, mechanical, and thermal properties. These nanotubes have been deployed both in pure and composite forms for obtaining highly efficient sensors in terms of sensitivity, robustness, and longevity. Among the wide range of applications that MWCNTs have been exploited for, strain-sensing has been one of the most popular ones due to the high mechanical flexibility of these carbon allotropes. The MWCNT-based sensors have been able to deduce a broad spectrum of macro- and micro-scaled tensions through structural changes. This paper highlights some of the well-approved conjugations of MWCNTs with different kinds of polymers and other conductive nanomaterials to form the electrodes of the strain sensors. It also underlines some of the measures that can be taken in the future to improve the quality of these MWCNT-based sensors for strain-related applications

Smart Sensing System for Early Detection of Bone Loss: Current Status and Future Possibilities

Bone loss and osteoporosis is a serious health problem worldwide. The impact of osteoporosis is far greater than many other serious health problems, such as breast and prostate cancers. Statistically, one in three women and one in five men over 50 years of age will experience osteoporotic fractures in their life. In this paper, the design and development of a portable IoT-based sensing system for early detection of bone loss have been presented. The CTx-I biomarker was measured in serum samples as a marker of bone resorption. A planar interdigital sensor was used to evaluate the changes in impedance by any variation in the level of CTx-I. Artificial antibodies were used to introduce selectivity to the sensor for CTx-I molecule. Artificial antibodies for CTx-I molecules were created using molecular imprinted polymer (MIP) technique in order to increase the stability of the system and reduce the production cost and complexity of the assay procedure. Real serum samples collected from sheep blood were tested and the result validation was done by using an ELISA kit. The PoC device was able to detect CTx-I concentration as low as 0.09 ng/mL. It exhibited an excellent linear behavior in the range of 0.1–2.5 ng/mL, which covers the normal reference ranges required for bone loss detection. Future possibilities to develop a smart toilet for simultaneous measurement of different bone turnover biomarkers was also discussed

Recent Advancement of the Sensors for Monitoring the Water Quality Parameters in Smart Fisheries Farming

Water quality is the most critical factor affecting fish health and performance in aquaculture production systems. Fish life is mostly dependent on the water fishes live in for all their needs. Therefore, it is essential to have a clear understanding of the water quality requirements of the fish. This research discusses the critical water parameters (temperature, pH, nitrate, phosphate, calcium, magnesium, and dissolved oxygen (DO)) for fisheries and reviews the existing sensors to detect those parameters. Moreover, this paper proposes a prospective solution for smart fisheries that will help to monitor water quality factors, make decisions based on the collected data, and adapt more quickly to changing conditions

Recent Advancement of the Sensors for Monitoring the Water Quality Parameters in Smart Fisheries Farming

Water quality is the most critical factor affecting fish health and performance in aquaculture production systems. Fish life is mostly dependent on the water fishes live in for all their needs. Therefore, it is essential to have a clear understanding of the water quality requirements of the fish. This research discusses the critical water parameters (temperature, pH, nitrate, phosphate, calcium, magnesium, and dissolved oxygen (DO)) for fisheries and reviews the existing sensors to detect those parameters. Moreover, this paper proposes a prospective solution for smart fisheries that will help to monitor water quality factors, make decisions based on the collected data, and adapt more quickly to changing conditions

Highly selective ion imprinted polymer based interdigital sensor for nitrite detection

This research proposed the real-time detection of nitrite by employing electrochemical impedance spectroscopy (EIS) technique incorporating an interdigital capacitive sensor. A self-assembled monolayer functionalized the sensing surface with embedded ion-imprinted polymer (IIP) with selectivity for nitrite ions were introduced. Syntheis and characterization of IIP are also explained to validate the polymerization technique. Some initial results using different concentrations of nitrite sample to validate the proposed method are also presented. The promising results highlight the extraordinary potential to develop low-cost, in-situ measurement system to detect nitrite contamination with real-time monitoring.5 page(s

A Critical Review of the Use of Graphene-Based Gas Sensors

The employment of graphene for multifunctional uses has been a cornerstone in sensing technology. Due to its excellent electrochemical properties, graphene has been used in its pure and composite forms to detect target molecules over a wide range of surfaces. The adsorption process on the graphene-based sensors has been studied in terms of the change in resistance and capacitance values for various industrial and environmental applications. This paper highlights the performance of graphene-based sensors for detecting different kinds of domestic and industrial gases. These graphene-based gas sensors have achieved enhanced output in terms of sensitivity and working range due to specific experimental parameters, such as elevated temperature, presence of particular gas-specific layers and integration with specific nanomaterials that assist with the adsorption of gases. The presented research work has been classified based on the physical nature of graphene used in conjugation with other processed materials. The detection of five different types of gases, including carbon dioxide (CO2), ammonia (NH3), hydrogen sulphide (H2S), nitrogen dioxide (NO2) and ethanol (C2H5OH) has been shown in the paper. The challenges of the current graphene-based gas sensors and their possible remedies have also been showcased in the paper