Abstract-Consumers expect water supply companies to deliver safe drinking water that meets both health quality standards and aesthetic requirements such as colour, turbidity, taste and odour. Current water quality assessment methods of these parameters, which form the basis for sound water resources management, are mainly laboratory based, require fresh supply of chemicals, trained staff and are time consuming. Real-time water quality monitoring is essential for National and International Health and Safety, as it can significantly reduce the level of damage and also the cost to remedy the problem. This paper critically analyses both commercially available and state-of-the-art research methods and devices suitable for real-time wastewater quality monitoring and suggests further developments in this area. In particular, the focus is made on the monitoring of nitrates and phosphates in wastewater and a novel microwave based method for instantaneous water quality assessment is suggested.Index terms: water quality monitoring, in situ analysis, optical methods, industry, nitrates and phosphates, lab on chip sensors, microwave sensors, solid-state sensors.
It is often preferable to avoid using divers to undertake sub-sea activities, the alternatives being autonomous or remotely operated robotic vehicles and manipulators. This will only be achievable if robust communications can be established through seawater. Presently for such sub-sea activities it is necessary to use acoustic modems, which are only capable of operating with data rates of up to 50kbs -1 . Optical sensors can also be used but these rely on clear water and in many sea conditions propagation beyond 10m is not possible. This paper will present new experimental results for electromagnetic wave propagation through seawater at MHz frequencies. These frequencies would enable the use of high speed data rates, suitable for a wide range of sub-sea activities.
Concrete failure will lead to serious safety concerns in the performance of a building structure. It is one of the biggest challenges for engineers to inspect and maintain the quality of concrete throughout the service years in order to prevent structural deterioration. To date, a lot of research is ongoing to develop different instruments to inspect concrete quality. Detection of moisture ingress is important in the structural monitoring of concrete. This paper presents a novel sensing technique using a smart antenna for the non-destructive evaluation of moisture content and deterioration inspection in concrete blocks. Two different standard concrete samples (United Kingdom and Malaysia) were investigated in this research. An electromagnetic (EM) sensor was designed and embedded inside the concrete to detect the moisture content within the structure. In addition, CST microwave studio was used to validate the theoretical model of the EM sensor against the test data. The results demonstrated that the EM sensor at 2.45 GHz is capable of detecting the moisture content in the concrete with linear regression of R2 = 0.9752. Furthermore, identification of different mix ratios of concrete were successfully demonstrated in this paper. In conclusion, the EM sensor is capable of detecting moisture content non-destructively and could be a potential technique for maintenance and quality control of the building performance.
We have designed a low-cost and reliable 2.45 GHz waveguide-based
applicator to generate a microwave plasma jet (MPJ) at atmospheric
pressure. The MPJ system consists of a 1-6 kW magnetron power supply, a
circulator, a water-cooled matched load and the applicator. The applicator
includes a tuning section, which is required to reduce the reflected power,
and the nozzle section. The plasma is formed by the interaction of the high
electrical field, generated by the microwave power, between the waveguide
aperture and the gas nozzle. A variety of gases have been used to produce
the plasma including argon, helium and nitrogen. A 2 kW, 2.45 GHz MPJ,
constructed using a rectangular waveguide WG9A (WR340), has been
investigated. An MPJ has been used for material processing applications
including cutting, welding, glass vitrification and quartz/ceramic
processing. This paper discusses the design parameters and the potential of
the MPJ for industrial applications and how the jet can be tailored to suit
different tasks, by adjusting the various parameters such as the type of
gas, the flow rate, the input power and the nozzle design.
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