Sensors for Everyday Life

A novel approach to measure both the particle and the NO₂ concentration in the exhaust of diesel engines during the roadworthiness test in the periodical technical inspection is presented. It is based on a multi-wavelength extinction measurement and a mathematical inversion algorithm to obtain the concentrations from the extinction readings. Such individual concentration values can deliver valuable insight into the cause of engine or exhaust aftertreatment defects. Furthermore the extended opacimeter provides future-proofness, if nitrous gas emissions are incorporated in the roadworthiness regulations. In addition to a detailed description of the multi-wavelength approach this chapter provides an overview of particle and nitrous gas emissions by diesel engines, the related legislation, the extinction measurement using standard opacimeters, and the physical background for this optical measurement method. The applicability of the multi-wavelength method is derived mathematically and validated with first experimental results as well as with simulations.

This chapter describes the elemental analytical technique of the fine particles using atomic emission spectroscopy system for an environmental pollution monitoring. Based on our previous measurement reports, differences of the usage between the laser-induced breakdown spectroscopy (LIBS) system and the helium-microwave-induced plasma-atomic emission spectroscopy (He-MIP-AES) system are explained. Both systems were developed to allow to fulfil the criteria prescribed by the Ministry of Environment, Japan, for measuring the chemical components of particulate matter (PM) by introducing additional original sampling systems. In current environmental monitoring systems, PMs are typically collected on trapping filters placed across Japan and classified as either suspended particulate matter (SPM) or PM2.5 depending on the size. The collected PMs are subsequently analysed with automated measurement instruments such as a piezo balance and with methods such as beta ray attenuation and light scattering. While these measurement methods allow the mass concentration of PMs in the air to be obtained at hourly intervals, the chemical composition of individual particles is analysed with time-intensive laboratory procedures. In contrast, the LIBS and He-MIP-AES measurement system allow the chemical compositions and particle sizes to be measured simultaneously in real time.

Real-time monitoring of heating, ventilation, and air conditioning (HVAC) systems is crucial to maintaining optimal performance such as providing thermal comfort and acceptable indoor air quality, guaranteeing energy saving, and assuring system reliability. In a realistic situation, HVAC systems can degrade in performance or even fail due to a variety of operational problems, such as stuck open or closed air dampers and water valves, supply or exhaust air fan faults, hot or chilled water pump faults, and inefficiencies in the way HVAC systems or pieces of equipemnt are controlled. This paper presents automatic fault detection techniques, as well as a key sensor sets selection approach that can help to maintain the performance of HVAC systems, and optimise fault detection results. One key step to make sure the approach succeeds is the sensor feature selection process. This paper implements the ensemble rapid centroid estimation (ERCE) as the data-driven sensor and feature selection algorithm, which is the core method to assure the automatic fault detection can function correctly. Instead of choosing sensors manually, ERCE method can automatically select representative features that are unique and relevant to the faults in a HVAC system. The methodology presented is implemented in real-world commercial buildings with experimental results showing that different types of faults are detected successfully.

This chapter is focused in the different optical structures and materials that have been used for the development of optical fiber humidity sensors. First, we will start with a short introduction of what relative humidity is, and why it has been extensively investigated. We will make also a brief summary of the different options that have been developed by now, showing the evolution of this research field. Then we will look more closely at the most used structures, the most common materials and the devices having greater sensitivity and resolution.

Different oxygen gas sensing technologies, i.e., potentiometric, amperometric, paramagnetic and tunable diode laser spectroscopy (TDLS) are reviewed in details. Special attention is given to the theoretical aspects and operation basics of the technologies, application limits and analyzers or system requirements. A comprehensive technologies review is supported with the latest developments trends especially on the potentiometric zirconia and tunable diode laser analyzers.

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.

The Wireless Sensors Network (WSN) is nowadays widely used to build decision support systems to solve many real-world problems. One of the most interesting fields having an increasing need of decision support systems is agricultural environment monitoring. Agricultural environment monitoring has become an important field of control and protection, providing real-time system and control communication with the physical world. An intelligent and smart WSN system can collect and process large amount of data from the beginning of the monitoring and manage air quality, soil conditions, to weather situations. Wireless sensors are used in a palm oil plantation to monitor the humidity, temperature and other parameters of a mother palm to find the best time to start a controlled pollination process. Pollination is the process of transferring pollen from the male reproductive organ to the female reproductive organ of a flower. The inaccuracy in determining pollination readiness of the oil palm flower could potentially cause a detrimental effect on the palm oil industry in the long run.

The objective of this study was to determine the level of water in a septic tank by inserting a waveguide at the top of the tank. A TDR (i.e. waveguide) probe is immersed in the water tank, through which a pulse signal is launched. The impedance mismatch occurs at the air-water interface and the bottom of the tank, which results in the reflection of the signal. This reflected signal is algebraically added to the incident signal. From the time difference between the incident and reflected signal, the distance between the TDR and the surface of water is calculated. The distance is generally twice the time traveled by the wave. Thus, the calculated distance helps in finding out the length of water in the tank. Additionally, the TDR was compared with a Doppler radar system to determine if the Doppler system would be a feasible non-contact measurement system as compared to the TDR.

The control and sanitation of water it’s a worldwide concerning problem. In particular is in developing countries where the need is more evident due to the lack of sources and appropriate structures to cope with the outbreaks of waterborne diseases. In most of cases, the cause of these significant epidemiological events have microbial origin. Despite of it the situation of water supplies and sanitation has improve all over the world in the last decades. Nanowire technology has already shown their ability to perform very effective and fast monitoring microbiological spoilage and quality control. The aim of this study was to test the ability of a novel S3 (Small Sensor System) nanowire device for the detection of complex mixtures of bacteria in potable water in order to approach into a real condition, in cooperation with GC-MS- SPME technique. The achieved results notably advocate the use of EN as a very easy to use, fast and accurate tool in water quality control.

This chapter presents a novel approach to monitor the quality of milk products, based on electromagnetic wave spectroscopy. A comparative analysis is made to demonstrate the effectiveness of using microwave sensors over the other types, existing in the wide field of sensing technology. Three broadly used commercial varieties of milk, namely skimmed, semi-skimmed, and whole milk types are considered for the test measurements. The overall quality parameters of these products obtained from the market are comparatively measured in terms of their composition and spoilage with reference to ageing. The experiments carried out have illustrated that the sensor was able to distinguish one milk type from another. Moreover, it was also able to differentiate between fresh and aged milk samples of a given milk type as the number of days passes. The methodology used here employs Vector Network Analyser to capture spectral signatures in the form of scattering parameters from electromagnetic wave sensors. These data are then analysed to evaluate quality monitoring process achieved by these sensors. This work offers a potential platform for an economical, less complicated, and real-time milk quality control mechanism that can be employed outside of the laboratories at medium or large scale retailers in milk supply chain hierarchy.

Parmigiano Reggiano (PR) cheese is produced from the bovine milk in a limited geographic area in northern Italy. It is one of the oldest traditional cheeses manufactured in Europe (XII century) and is still one of the most esteemed Protected Designation of Origin (PDO) cheeses of Italy. The Parmigiano Reggiano Cheese Consortium (CFPR) is the institutional system that covers all the cheese dairy factories and controls the cheese production in terms of cow feeding, cheese manufacture and ripening processes. The aim of this study was to establish a new, rapid, portable, easy-to-use, economic and non-destructive fouling based on nanowire technology device (S3) to control the presence of false grated PR. All the analyzed samples were collected from the Consortium that picked the samples produced in different European countries (three samples from Germany, one from Ireland, one from Latvia and one from Lithuania). The achieved samples were analyzed with the cooperation of multidisciplinary technologies like Colorimeter, pH Meter, GC-MS with SPME and the new nanowire gas sensor device (S3). The applied techniques were able to create a specific database for the S3 device, capable to give results in a few minutes. The use of a Small Sensor System (S3) device to determine the specific volatile organic compounds (VOCs) of the grated PR is a promising approach offering, at the same time, a simpler, faster and easier to handle (no specialized technicians are required) solution with respect to the analytical techniques (GC-MS, HPLC). However, from the commercial point-of-view, low cost and reduced power consumption are the fundamental features that should entail a sensor device. In this study, S3 device was applied and found to be efficient in the discrimination of the different grated PR cheese samples. In particular, the discrimination was checked quali-quantitatively thanks to the analysis performed with the GC-MS-SPME technique. In fact, the achieved results demonstrated the quali-quantitative differences of the VOCs emitted by the samples. S3 device is a promising tool for the quality discrimination of the PR cheese and other foodstuffs. In our future works, specific database of the grated PR will be amplified for the direct use of S3 in the cheese-chain productions.

Food adulteration is the process of adding or mixing of substance(s) that should not be into food products for financial gain or other motives. Food adulteration is a serious problem worldwide not just because it is a fraud to consumer, but it can also harm the health and causes serious consequences to the well being of people. Among the food products, edible oil has been identified as the top ingredient involved in food fraud. Studies show that adulteration in fats and oils are mainly economically motivated and in some cases intended to enhance food flavor. In general, adulteration of edible oil causes two great concerns to the consumer. First, it concerns consumers that practice vegetarian diet or followers of religions that prohibit from consuming pig, pork or any of its products. Second, it may cause serious health related issues particularly those who have allergies to certain types of substances or consumers who suffer coronary disease. Several conventional techniques have been utilized in order to study food adulteration particularly on fats and oil, such as polymerase chain reaction, differential scanning calorimetry, electronic nose and chromatography. Until recently, dielectric spectroscopy technique that have been widely used to analyze food products, attain research community’s attention in the study of adulteration on fats and oil. In this chapter, a review on conventional techniques and dielectric spectroscopy approach for analyzing food products are presented. In particular, a review on dielectric spectroscopy to study adulteration in fats and oils and recent work on lard detection at both low and high frequency range are discussed. Results show that dielectric sensing can be a great technology to detect lard adulterated edible oil and applying data analysis technique can further enhance the detection ability.

One of the biggest challenges facing the widespread implementation of wireless sensor networks is wireless interference and radio-frequency (RF) spectrum crowding. Even today, wireless networks are already straining under society’s relentless demand for higher data rates and constant connectivity. For wireless sensor networks to become a reality, research on increasing network capacity and allocating spectral resources must necessarily involve new techniques for handling wireless interference scalably and efficiently. This chapter focuses on analog interference cancellation using optical signal processing as a path towards operating in the presence of wireless interference. Canceling interference before it enters a receiver allows wireless sensor networks to conserve scarce spectral resources and relax system requirements, resulting in robust operation, increased battery life, and reduced size and cost. Through its unique physics, optics enables new RF functionalities that are extremely valuable to canceling interference in the RF front-end, chief among them being wide processing bandwidth. The wideband nature of optics is key to anticipating the rise in data rates, bandwidths, and channel counts of future networks, and endows optics with the potential to realize true multiband radio transceivers. Our goal in this chapter is to present an overview of optical-based RF interference cancellation and discuss the key characteristics that make optics an outstanding technology platform for the job. We then show several system architectures and a sample of their experimental performance. We leave the readers with a discussion on the future prospects for this technology, focusing specifically on photonic integrated circuits.