Artificial Neural Network and Wavelet Features Extraction Applications in Nitrate and Sulphate Water Contamination Estimation

This work expounds the review of non-destructive evaluation using near-field sensors and its application in environmental monitoring. Star array configuration of planar electromagnetic sensor is explained in this work for nitrate and sulphate detection in water. The experimental results show that the star array planar electromagnetic sensor was able to detect nitrate and sulphate at different concentrations. Artificial Neural Networks (ANN) is used to classify different levels of nitrate and sulphate contaminations in water sources. The star array planar electromagnetic sensors were subjected to different water samples contaminated by nitrate and sulphate. Classification using Wavelet Transform (WT) was applied to extract the output signals features. These features were fed to ANN consequently, for the classification of different levels of nitrate and sulphate concentration in water. The model is capable of distinguishing the concentration level in the presence of other types of contamination with a root mean square error (RMSE) of 0.0132 or 98.68% accuracy

Objective and subjective characterization of saxophone reeds

The subjective quality of single cane reeds used for saxophone or clarinet may be very different from a reed to another although reeds present the same shape and the same strength. In this work, we propose to compare three approaches for the characterization of reeds properties. The first approach consists in measuring the reed mechanical response ("in vitro" measurement) by means of a specific bench which gives equivalent dynamic parameters (mass, damping, stiffness) of the first vibration mode. The second approach deals with the measurement of playing parameters "in vivo", using specific sensors mounted on the instrument mouthpiece. These measurements provide specific parameters in playing condition, such as the threshold pressure or the spectral centroid of the sounds. Finally, subjective tests are performed with a musician in order to assess the reeds according to subjective criteria, characteristic of the perceived quality. Different reeds chosen for their subjective differences (rather difficult and dark, medium, rather easy and bright) are characterized by the three methods. First results show that correlations can be established between "in vivo" measurements and subjective assessments

The design and development of a planar coil sensor for angular displacements

The increased prevalence of wearable sensing devices is accelerating the development of personalised medical devices for monitoring the human condition. The measurement of joint posture and kinematics is particularly relevant in areas of physiotherapy and in the management of diseases. Existing sensors for performing these tasks are however, either inaccurate or too technically complex and obtrusive. A novel approach has been taken to develop a new type of sensor for angular displacement sensing. This thesis describes the development of a series of novel inductive planar coil sensors for measuring angular displacement. The small profile of these sensors makes them ideal for integration into garments as part of wearable devices. The main objective of this work was to design a planar coil topology, based on an inductive methodology, suitable for measuring angular displacements typically observed in finger articulation. Finite Element Method software was initially employed to determine the feasibility of various coil topologies. The planar coils were subsequently manufactured on several types of substrate including rigid printed circuit boards and flexible polyester films incorporating an iron-based amorphous ribbon as the inductive element. A series of experimental investigations involving inductance and stray field measurements, were performed on a range of coil topologies and layered configurations. The resulting data provided information relating sensor performance to positioning of the amorphous element and its overall angular displacement. The main findings showed that inductance change was not frequency dependent in the range (20 – 100) kHz but decreased by up to 15% for large angular displacements when utilising a figure-of-eight coil design. The sensors developed in this work provide significantly better accuracy than current resistive-based flexible sensors. Further refinements to coil design and optimisation of the inductive element’s magnetic properties is expected to yield further improvements in sensor performance providing an excellent platform for future wearable technologies

TEMPLATED SINGLE-CHAIN POLYMER-BASED ELECTROCHEMICAL SENSING

A target receptor is an essential component in developing selective biological and chemical sensors. Among various approaches in receptor implementation, templated polymers are synthetic biochemical receptors that mimic natural molecular recognition. They have the favorable arrangement of polymer structures to be steady in harsh conditions and can also be custom tailored to exhibit target affinity as well as interfacing with transducers. Effective templated polymer synthesis depends on the co-polymerization of functional monomers which will interact with the sensing molecule. This thesis proposes a rational design approach towards the integration of templated polymers with electrochemical sensing. The synthesized single-chain label-free flexible polymers with binding sites show selective affinity toward both electroactive and non-electroactive target molecule. This thesis proposes a novel approach in electrochemical templated polymer-based sensing platform. The developed platform shows binding-induced changes in the electron transfer kinetics at the templated polymer-attached electrode when the target molecule binds specifically to the receptor. In this work, a stimuli-responsive single-chain copolymer was developed for explicit analyte detection of 4-nitrophenol, a neurotoxin and environmental pollutant, and L-glutamate, a well-known neurochemical. The polymer backbone experiences a conformation change upon template binding and the electrochemical measurement can be used to characterize these changes. This new detection approach can be used for label-free sensing of various non-electroactive chemical species and can potentially lead to the development of a non-enzymatic electrochemical sensors