Improvements in temperature measurement

This submission for the degree of Doctor of Science describes work initiated, led or contributed to by Dr Graham Machin, a graduate of the University of Birmingham, over the last 25 years. The submission comprises of six main parts, illustrating the different contributions made to the area of temperature measurement. In brief these are: • Development and improvement of non-contact thermometry standards • Comparisons of non-contact thermometry scales, including the development of new methods of comparison • Contributions to the development of high temperature fixed points as new temperature references above the freezing point of copper (1 084.62 °C) • Development of methods for the mitigation of temperature sensor drift at high temperatures • Improvements and innovations in medical thermometry - in a variety of settings • Leadership in international temperature measurement research The thesis begins with an introduction to the subject of the research, including a brief overview of the presented papers. Then a list of the presented papers is given followed by copies of the manuscripts. The thesis ends with an Appendix containing an up to date publication record

An Investigation of Radiometer and Antenna Properties for Microwave Thermography

Microwave thermography obtains information about the subcutaneous body temperature by a spectral measurement of the intensity of the natural thermally generated radiation emitted by the body tissues. At lower microwave frequencies the thermal radiation can penetrate through biological tissue for significant distances. The microwave thermal radiation from inside the body can be detected and measured non-invasively at the skin surface by the microwave thermography technique, which uses a radiometer to measure the radiation which is received from an antenna on the skin. In the microwave region the radiative power received from a volume of material has a dependence on viewed tissue temperature T(r) of the form, where k is the Boltzmann's constant, B the measurement bandwidth, c(r) is the relative contribution from a volume element dv (the antenna weighting function). The weighting function, c(r), depends on the structure and the dielectric properties of the tissue being viewed, the measurement frequency and the characteristics of the antenna. In any practical radiometer system the body microwave thermal signal has to be measured along with a similar noise signal generated in the radiometer circuits. The work described in this thesis is intended to lead to improvement in the performance of microwave thermography equipment through investigations of antenna weighting functions and radiometer circuit noise sources. All work has been carried out at 3.2 GHz, the central operating frequency of the existing Glasgow developed microwave thermography system. The effects of input circuit losses on the operation of the form of Dicke radiometer used for the Glasgow equipment have been investigated using a computational model and compared with measurements made on test circuits. Very good agreement has been obtained for modelled and measured behaviour. The losses contributed by the microstrip circuit structure, that must be used in the radiometer at 3.2 GHz, have been investigated in detail. Microwave correlation radiometry, by "add and square" method, has been applied to the received signals from a crossed-pair antenna arrangement, the antennas being arranged to view a common region at a certain depth. The antenna response has been investigated using a noise source and by the nonresonant perturbation technique. The received pattern formed by the product of the individual antenna patterns gives a maximum depth in phantom dielectric material. The depth can be adjusted by changing the spacing of the antennas and the phase in an antenna path. However, the pattern is modulated by a set of positive and negative interference fringes so that the complete receive pattern has a complicated form. On uniform temperature distributions the total radiometric signal is zero with the positive and negative contributions cancelling each other out. The fringe modulation can be removed by placing the antennas close enough together, The pattern is then simple and gives a modest maximum response at a known depth in a known material. The radiometer system remains sensitive to the temperature gradients only and the wide range of dielectric properties and tissue structures in the region being investigated usually makes the system response difficult to interpret. For crossed-pair antennas in phase the effective penetration depth in high-and medium-water content tissues is about 2.5 cm at a frequency of 3.2 GHz. The field pattern observed was of the form expected from the measurements of the individual antenna behaviour with the appropriate interference pattern superimposed. The nonresonant perturbation technique has been developed and applied to assist the development of the medical application of both microwave thermographic temperature measurement and microwave hyperthermia induction. These techniques require the electromagnetic field patterns of the special antennas used to be known. These antennas are often formed by short lengths of rectangular or cylindrical waveguide loaded with a low-loss dielectric material to achieve good coupling to body tissues. The high microwave attenuation in biological materials requires the field configurations to be measured close to the antenna aperture in the near-field wave. The nonresonant perturbation is a simple technique which can be used to measure electromagnetic fields in lossy material close to the antenna. It has been applied here to measure accurately the antenna weighting function and the effective penetration depth in tissue simulating dielectric phantom materials. (Abstract shortened by ProQuest.)

Water-filtered Infrared A (wIRA) Irradiation

The aim of this open access book is to provide a unique, timely, critical and comprehensive compilation of more than 30 years of robust international experimental and clinical research related to the basic science and therapeutic application of water-filtered infrared-A (wIRA) and hyperthermia in oncology, psychiatry (depression), musculoskeletal disorders, dermatology, infectiology, and surgery. This is an internationally absolutely unique attempt which publication is timely and of great interest in medical as well as in natural sciences. The aim is to enhance communication and advance the use of heat therapy for patient benefit, and to generate an environment in which anyone with an interest in hyperthermia can discuss, collaborate, network, and share events and resources. Productive dialogue and discussion among scientists and practitioners on issues relating to hyperthermia therapy is essential, especially relating to thermal transmission by water-filtered infrared-A (wIRA). The specificity and advantage of this technology is its tolerance by tissue, and its penetration of up to 3 cm allows the delivery of high heat dosages that are relevant across multiple clinical indications. Currently, wIRA is being applied in Austria, Germany, Portugal, Switzerland, The Netherlands, UK and the USA. The authors’ hope is that its use will increase in these countries, and also expand into others. This book will be an invaluable tool for oncologists, surgeons, dermatologists as well as physiotherapists

Water-Filtered Infrared A (wIRA) Irradiation: Novel Treatment Options for Chlamydial Infections

wIRA has been shown to reduce extracellular chlamydial forms and intracellular chlamydial inclusions in different cell culture infection models, and similarly on different human or animal chlamydial species. Repeated wIRA applications increase the efficacy of treatment in vitro, and in vivo in a guinea pig ocular model of inclusion conjunctivitis. The guinea pig model reflects the human ocular disease trachoma, the most common cause of infectious blindness worldwide which is caused by ocular strains of Chlamydia trachomatis. In this model, ocular wIRA treatment reduces conjunctival chlamydial load and ocular pathology. First insights into the mechanisms of anti-chlamydial activity indicate the involvement of both thermal and non-thermal effects. Interestingly, wIRA treatment of non-infected cells renders them more resistant to subsequent chlamydial infection, suggesting cell-related mechanisms that might involve cytochrome C. Further studies envisage the refinement of wIRA treatment protocols, the enhancement of anti-chlamydial activity by adding photodynamic substances, and characterization of the mechanisms underlying the therapeutic benefit of wIRA

Water-filtered Infrared A (wIRA) Irradiation

The aim of this open access book is to provide a unique, timely, critical and comprehensive compilation of more than 30 years of robust international experimental and clinical research related to the basic science and therapeutic application of water-filtered infrared-A (wIRA) and hyperthermia in oncology, psychiatry (depression), musculoskeletal disorders, dermatology, infectiology, and surgery. This is an internationally absolutely unique attempt which publication is timely and of great interest in medical as well as in natural sciences. The aim is to enhance communication and advance the use of heat therapy for patient benefit, and to generate an environment in which anyone with an interest in hyperthermia can discuss, collaborate, network, and share events and resources. Productive dialogue and discussion among scientists and practitioners on issues relating to hyperthermia therapy is essential, especially relating to thermal transmission by water-filtered infrared-A (wIRA). The specificity and advantage of this technology is its tolerance by tissue, and its penetration of up to 3 cm allows the delivery of high heat dosages that are relevant across multiple clinical indications. Currently, wIRA is being applied in Austria, Germany, Portugal, Switzerland, The Netherlands, UK and the USA. The authors’ hope is that its use will increase in these countries, and also expand into others. This book will be an invaluable tool for oncologists, surgeons, dermatologists as well as physiotherapists

Dynamic Thermal Imaging for Intraoperative Monitoring of Neuronal Activity and Cortical Perfusion

Neurosurgery is a demanding medical discipline that requires a complex interplay of several neuroimaging techniques. This allows structural as well as functional information to be recovered and then visualized to the surgeon. In the case of tumor resections this approach allows more fine-grained differentiation of healthy and pathological tissue which positively influences the postoperative outcome as well as the patient's quality of life. In this work, we will discuss several approaches to establish thermal imaging as a novel neuroimaging technique to primarily visualize neural activity and perfusion state in case of ischaemic stroke. Both applications require novel methods for data-preprocessing, visualization, pattern recognition as well as regression analysis of intraoperative thermal imaging. Online multimodal integration of preoperative and intraoperative data is accomplished by a 2D-3D image registration and image fusion framework with an average accuracy of 2.46 mm. In navigated surgeries, the proposed framework generally provides all necessary tools to project intraoperative 2D imaging data onto preoperative 3D volumetric datasets like 3D MR or CT imaging. Additionally, a fast machine learning framework for the recognition of cortical NaCl rinsings will be discussed throughout this thesis. Hereby, the standardized quantification of tissue perfusion by means of an approximated heating model can be achieved. Classifying the parameters of these models yields a map of connected areas, for which we have shown that these areas correlate with the demarcation caused by an ischaemic stroke segmented in postoperative CT datasets. Finally, a semiparametric regression model has been developed for intraoperative neural activity monitoring of the somatosensory cortex by somatosensory evoked potentials. These results were correlated with neural activity of optical imaging. We found that thermal imaging yields comparable results, yet doesn't share the limitations of optical imaging. In this thesis we would like to emphasize that thermal imaging depicts a novel and valid tool for both intraoperative functional and structural neuroimaging

Rahvusvahelise temperatuuriskaala esitamine ja edastamine kombineeritud meetodil

Väitekirja elektrooniline versioon ei sisalda publikatsioone.Kaasaegse ühiskonna konkurentsivõimeliseks ja jätkusuutlikuks toimimiseks on oluline tagada mõõtetulemuste usaldusväärsus ja rahvusvaheline ekvivalentsus. Usaldusväärsed mõõtmistulemused on vajalikud teadusuuringutes, tööstuses, kaubanduses, riiklikus järelevalves, meditsiiniteenuste osutamisel, keskkonnakaitses ja paljudel teistel erialadel. Lisaks riigisiseste mõõtetulemuste seostatuse kindlustamisele tuleb igal riigil täita ka rahvusvahelisi leppeid, mis soodustavad riikidevahelist kaupade ja teenuste vaba liikumist ning aitavad tugevdada riigi majanduslikku arengut ja konkurentsivõimet. On heaks tavaks, et iga iseseisev riik hoolitseb riikliku mõõtesüsteemi arendamise ja toimimise eest. Enamike riikide mõõtesüsteemide arendamine on kestnud juba rohkem kui sada aastat. Aeg-ajalt tekib uusi iseseisvaid riike, mille arenev majandus vajab suhteliselt kiireid lahendusi usaldusväärsete mõõtetulemuste tagamiseks. Riikliku mõõtesüsteemi ja riigietalonide vajadus Eestis tekkis eelmise sajandi üheksakümnendatel aastatel. Riigietalonide arendamine on aeganõudev ja ressursimahukas protsess, mida tuleb piiratud vahendite optimaalseks kasutamises hoolikalt planeerida. Majandus ja Kommunikatsiooniministeerium kaardistas 2002. aastal mõõteteenuste vajadused, mille tagamiseks oli tarvilik välja arendada etalonibaas Eestis. Vajaduste rahuldamiseks arendati välja riigietalonid rahvusvahelise temperatuuriskaala ITS 90 taasesitamiseks mõõtepiirkonnas (-40 ... +300) °C ligikaudsel laiendmõõtemääramatuse tasemel 10 mK. Antud mõõtemääramatuse tase on üldjuhul suurem kui temperatuuriskaala esitamisel primaartasemel, kuid sellist taset on keeruline saavutada ainult sekundaarseid vahendeid kasutades. Seetõttu on temperatuuriskaala esitamiseks Eesti riigietalonilaboris (Metrosert) arendatud primaar- ja sekundaarmeetodeid kombineeriv meetod. Eesti temperatuuri riigietaloni näitel kirjeldatud meetod on kasutatav ka teistes laborites, mille eesmärgiks on tagada mõõteteenused sarnasel mõõtemääramatuse tasemel. Väljaarendatud meetod toetab laia valikut erinevaid mõõterakendusi sh kõikide teiste Eesti riigietalonide mõõtevõimet.Reliability and international equivalence of measurement results are important issues in sustainable operation and development of the modern society. Discrepancies in measurement results have even been identified as one of the major barriers to trade and innovation. It is a common practice that each independent country has established a national measurement infrastructure. In most countries these infrastructures have been developed in a process of scientific research over more than hundred years. Nevertheless new independent countries with evolving economy and needs for a reliable metrology system are still emerging. This was also the case for Estonia, where the development of national standards and measurement scales started only in the 1990-s. Establishment of a new national measurement standard must be designed carefully for optimal use of limited resources. The study describes establishment and dissemination of the national temperature scale in Estonia with the link to the international temperature scale ITS 90 in the temperature range from 40 °C to +300 °C with approximate expanded measurement uncertainty of 10 mK. The temperature range and uncertainty level originate from the actual needs mapped by a special survey carried out by the Ministry of Economic Affairs and Communications in 2002. The stated uncertainty level is generally larger than usually obtained by primary realizations, but too small to be achieved by secondary methods only. Therefore the temperature scale is established by combining primary and secondary techniques of the ITS 90. The combined method for establishment of the temperature scale is described on the example of Metrosert – the laboratory for national standards in Estonia, but it can be also applied in other laboratories aiming the similar measurement range and capability. The methods described in the study are important as they support wide area of measurement applications including establishment of all officially approved national measurement scales in Estonia

NASA Tech Briefs, September 2011

Topics covered include: Fused Reality for Enhanced Flight Test Capabilities; Thermography to Inspect Insulation of Large Cryogenic Tanks; Crush Test Abuse Stand; Test Generator for MATLAB Simulations; Dynamic Monitoring of Cleanroom Fallout Using an Air Particle Counter; Enhancement to Non-Contacting Stress Measurement of Blade Vibration Frequency; Positively Verifying Mating of Previously Unverifiable Flight Connectors; Radiation-Tolerant Intelligent Memory Stack - RTIMS; Ultra-Low-Dropout Linear Regulator; Excitation of a Parallel Plate Waveguide by an Array of Rectangular Waveguides; FPGA for Power Control of MSL Avionics; UAVSAR Active Electronically Scanned Array; Lockout/Tagout (LOTO) Simulator; Silicon Carbide Mounts for Fabry-Perot Interferometers; Measuring the In-Process Figure, Final Prescription, and System Alignment of Large; Optics and Segmented Mirrors Using Lidar Metrology; Fiber-Reinforced Reactive Nano-Epoxy Composites; Polymerization Initiated at the Sidewalls of Carbon Nanotubes; Metal-Matrix/Hollow-Ceramic-Sphere Composites; Piezoelectrically Enhanced Photocathodes; Iridium-Doped Ruthenium Oxide Catalyst for Oxygen Evolution; Improved Mo-Re VPS Alloys for High-Temperature Uses; Data Service Provider Cost Estimation Tool; Hybrid Power Management-Based Vehicle Architecture; Force Limit System; Levitated Duct Fan (LDF) Aircraft Auxiliary Generator; Compact, Two-Sided Structural Cold Plate Configuration; AN Fitting Reconditioning Tool; Active Response Gravity Offload System; Method and Apparatus for Forming Nanodroplets; Rapid Detection of the Varicella Zoster Virus in Saliva; Improved Devices for Collecting Sweat for Chemical Analysis; Phase-Controlled Magnetic Mirror for Wavefront Correction; and Frame-Transfer Gating Raman Spectroscopy for Time-Resolved Multiscalar Combustion Diagnostics

Advanced Diagnostic Techniques Applied to Polymer Electrolyte Fuel Cells

Polymer electrolyte fuel cells (PEFCs) are among the most promising energy conversion technologies for a broad range of applications, offering zero-emission electricity generation by converting hydrogen directly into electrical energy at high efficiencies. Tremendous advancements have been made in terms of performance and durability but technological challenges still exist which hinder their widespread adoption; these challenges range from material durability to system design and operating strategies. Developing this technology requires a comprehensive understanding of its fundamental operation, coupled with effective diagnostic techniques. Performance, temperature and hydration in a PEFC is a complex relationship governed by cause-and-effect, where a change in one factor alters the other. These problems are exacerbated during scale-up, advancing from small lab-scale single cells to large commercial automotive stacks, where operational heterogeneities encourage large current and temperature variations, resulting in varied local degradation rates and inefficient PEFC performance. This study characterises these parameters in-operando by adopting diagnostic techniques such as current, temperature and pressure mapping, coupled with electrochemical techniques, to garner a broader understanding of the formation of these heterogeneities. The development of new diagnostic techniques for both research and industry is also crucial for the commercialisation of PEFCs, as stack-level diagnostic resources are limited. These are required to be straightforward in application and interpretation, cost-effective and with short testing times. Novel diagnostic techniques are presented in this study which aim to bridge this gap in the diagnostic sector. Lock-in thermography is used to image sub-surface water content during cell operation using a thermal imaging camera, producing water distribution images at various penetration depths. A complementary transfer function technique is also developed, termed heat-stimulus thermo-electric impedance spectroscopy (HS-TEIS), which considers the complex relationship between imposed temperature change and electrical response as a function of frequency