171 shared publications
Smart Materials and Surfaces Laboratory, Faculty of Engineering & Environment, Northumbria University, Ellison Place, Newcastle upon Tyne NE1 8ST, United Kingdom
92 shared publications
School of Science and Technology; Nottingham Trent University; Clifton Campus, Clifton Lane Nottingham UK NG11 8NS
48 shared publications
Faculty of Technology and Bionics, Rhein-Waal University of Applied Sciences, Marie-Curie-Straße 1, D-47533 Kleve, Germany
38 shared publications
Nottingham Trent University, School of Science and Technology, Clifton Lane, Clifton, Nottingham, NG11 8NS, UK.
19 shared publications
Advanced Textiles Research Group, School of Art & Design, Nottingham Trent University, Bonington Building, Dryden Street, Nottingham NG1 4GG, UK
(2007 - 2017)
Sensors based on the measurement of nuclear magnetic resonance (NMR) relaxation times have been increasing in popularity, due in part to developments in permanent magnet technology. Such sensors tend to measure the spin-lattice (longitudinal) relaxation time T1, or the effective spin-spin (transverse) relaxation time T2eff. It is important when developing sensors that there are a range of safe and repeatable calibration samples to aid in their calibration and testing. For the spin-spin relaxation times different viscosities of PDMS oil provide a suitable range of safe test materials. However, for the spin-lattice relaxation times, available options are not as safe to use and typically consist of different concentrations of Nickel Sulphate or Copper Sulfate solutions. In this work we report the use of solutions and gels comprising full fat milk powder as a safe and inexpensive material that can affect the longitudinal relaxation Time over a very wide range of values. We demonstrate that concentrations in distilled water from 5% to 64% give T1 values from 1.8s down to 348 ms respectively. In addition to demonstrating their effectiveness for magnetic resonance sensors, validation of the range of T1 values is undertaken on a high field clinical MRI system.
Body temperature is an important parameter to measure in a number of fields such as medicine and sport. In medicine temperature changes can indicate underlying pathologies such as wound infections, while in sport temperature can be associated to a change in performance. In both cases a wearable temperature monitoring solution is preferable. In earlier work a temperature sensing yarn has been developed and characterised. The yarns were constructed by embedding an off-the-shelf thermistor into a polymer resin micro-pod and then into the fibres of a yarn. This process created a temperature sensing yarn that was conformal, drapeable, mechanically resilient, and washable. This work builds on this early study with the purposes of identifying the steady state error bought about on the temperature measurements as a result of the polymer resin and yarn fibres. Here a wider range of temperatures than previously explored were investigated. Additionally two types of polymer resin with different thermal properties have been tested, with varying thicknesses, for the encapsulation of the thermistor. This provides useful additional information for optimising the temperature sensing yarn design.
Sensors that measure magnetic resonance relaxation times are increasingly finding applications in areas such as food and drink authenticity and waste water treatment process control. Modern permanent magnets are used to provide the static magnetic field in many commercial instruments and advances in electronics, such as field programmable gate arrays, have provided lower cost console electronics for generating the series of RF pulses and detecting the resultant magnetic resonance signals. One area that still remains prohibitively expensive for many sensor applications of pulsed magnetic resonance is the requirement for a high frequency power amplifier. With many permanent magnet sensors providing a magnetic field in the 0.25T to 0.5T range, a power amplifier that operates in the 10MHz to 20MHz rage is required. This frequency range falls at the low end of the amateur “ham” radio frequency spectra designated for private recreation and non-commercial exchange of messages. In this work we demonstrate that low cost commercial amateur radio amplifiers can be simply modified, to operate as pulsed magnetic resonance power amplifiers. We demonstrate two amplifier systems, one medium power that can be constructed for less than Euro 100 and a second higher power system which produces comparable results to commercial pulse amplifiers that are an order of magnitude more expensive. Data is presented using both the commercial NMR MOUSE and a permanent magnet system used for monitoring the clog state of constructed wetlands.