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1
Тесленко, Віктор Сергійович. "Вимірювальна система параметрів потоку рідини." Master's thesis, Київ, 2018. https://ela.kpi.ua/handle/123456789/25814.
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Магістерська дисертація складається зі вступу, 3 розділів та має 92
сторінок, 49 зображень, 32 таблиць та 21 посилань. Перший розділ містить огляд
літератури, опис конструкції вібраційного густиноміра та принципу роботи. В
другому розділі розроблено математичну модель, проведено її дослідження. В
третьому розділі розроблено стартап-проект.
Актуальністю роботи є удосконалити прилад для вимірювання густини з
покращеними властивостями, що буде працювати при підвищеній забрудненості.
Об'єктом дослідження є система контролю густини рідини в трубопроводі.
Предметом дослідження є прилади для вимірювання густини речовини.
Мета роботи полягає в дослідженні динамічної характеристики
вібраційного густиноміра.
Для досягнення мети поставлені наступні завдання:
1. Розглянути різні типи густиномірів та порівняти технічні
характеристики вже існуючих приладів;
2. Розробити параметричну структурну схему для обраного
густиноміра;
3. Провести розрахунок і аналіз густиноміра;
4. Розробити та дослідити математичну модель.The master's dissertation consists of an introduction, 3 chapters and has 92 pages, 49 images, 32 tables and 21 references. The first section contains a review of the literature, a description of the design of the vibrating density and the principle of operation. In the second section a mathematical model was developed, its research was conducted. In the third section a startup project was developed. The urgency of the work is to improve the device for measuring the density with improved properties, which will work with increased pollution. The object of the study is a system for monitoring the density of the liquid in the pipeline. The subject of the study is the instruments for measuring the density of the substance. The purpose of the work is to study the dynamic characteristics of the vibration density. To achieve the goal set the following tasks: 1. Consider different types of densities and compare the specifications of already existing devices; 2. To develop a parametric structural scheme for the selected density; 3. Conduct calculation and analysis of the density; 4. Develop and explore a mathematical model. Keywords: density meter, vibration, mathematical model, transient process.
Магистерская диссертация состоит из введения, 3 разделов и имеет 92 страниц, 49 изображений, 32 таблиц и 21 ссылок. Первый раздел содержит обзор литературы, описание конструкции вибрационного плотномера и принципа работы. В втором разделе разработана математическая модель, проведено ее исследование. В третьей главе разработаны стартап-проект. Актуальностью работы является усовершенствовать прибор для измерения плотности с улучшенными свойствами, будет работать при повышенной загрязненности. Объектом исследования является система контроля плотности жидкости в трубопроводе. Предметом исследования является приборы для измерения плотности вещества. Цель работы заключается в исследовании динамической характеристики вибрационного плотномера. Для достижения цели поставлены следующие задачи: 1. Рассмотреть различные типы плотномеров и сравнить технические характеристики уже существующих приборов; 2. Разработать параметрическую структурную схему для выбранного плотномера; 3. Провести расчет и анализ плотномера; 4. Разработать и исследовать математическую модель.
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Guo, Zhiquan. "Development and characterization of Si₃N₄-based composites for high-temperature sensor applications." Thesis, Queen Mary, University of London, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.443580.
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Salisbury, Andrew Christopher. "The development of an AC current transducer using printed circuit board techniques." Thesis, Lancaster University, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.431738.
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Manrique, de Lara Bordoy Maria. "Development of an integrated model of vibrating element fluid-property sensors." Thesis, Imperial College London, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.423318.
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Munusamy, Rajkumar. "Cordless displacement sensor using Fe₇₇_.â‚…Si₇_.â‚…Bâ‚â‚… and Metglas 2605SC magnetostrictive materials." Thesis, University of Hull, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.440228.
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Myers, Christopher Phillip. "Chemical vapour deposition of metals and metal oxides for trial as potential gas sensors." Thesis, Keele University, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.401150.
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Furnival, Benjamin John Dylan. "Silicon carbide based gas sensor arrays for deployment within hostile environments." Thesis, University of Newcastle Upon Tyne, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.606732.
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The ability to determine the gaseous constituents of hazardous environments is of interest for a wide variety of applications including; emission control, nuclear waste storage and space exploration. Traditional Si-based technology has poor resilience and is unable to operate at temperatures much above 170°C. A viable alternative is SiC which has a wide band-gap and Si to C bonding, enabling it to operate at extreme temperatures, in high radiation flux and in corrosive ambients. SiC-based MIS capacitors have previously been shown to be sensitive to a range of gas species including; H2, O2 and H2S. However, these structures often reveal cross-sensitivity to multiple gas species and in order to enhance selectivity towards a target gas species or enable simultaneously monitoring of multiple gas species, a sensor array is required. The development of Ohmic contacts on 4H-SiC is crucial for a wide range of device structures. However, after high temperature post-processing, Ohmic behaviour has been found to deteriorate. This study reveals that careful replacement of the contact metallization can significantly recover the Ohmic behaviour, an enabling technology for the resilient sensor array. After optimization of a Ti02/Si02 high-x dielectric stack, a variety of SiC-based MIS capacitors were fabricated using combinations of Ni, Pd or Pt . gate contacts and Ti02 or Hf02 high-x dielectric layers. The C-V characteristics of these devices were investigated from 10KHz to 3 MHz and then at intervals during exposure to 400°C and 500 °C in air, showing reliable operation for at least 1000 hours and failure shortly after 143 hours respectively. The mechanisms responsible for this degradation were studied with SIMS and AFM analysis, which revealed that Ti and Cr have diffused into the Hf02 during annealing, possibly introducing additional defects. Using a combination of these capacitors a resilient SiC-based sensor array has been established. The C-V and I-V characteristics from this array have been examined in N2 at between 50°C and 400°C, prior to its C-V response being recorded at 300°C in a variety of H2, O2 and H2/02 ambients. The selectivity of a MIS capacitor between H2 and O2 has been found to be strongly dependant on contact material, whilst choice in high-x dielectric has a substantial influence on H2 sensitivity. The use of MLR analysis on the resulting data is found to enable the array to discriminate between H2/02 mixed gas ambients and make reasonable predictions of their concentrations, to generally within= 600 ppm for H2 and > 200 ppm for O2.
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Saif, Waleed Abdulwahed. "Localization in wireless sensor networks." Thesis, University of Leeds, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.555845.
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In this thesis we examine localization in wireless sensor networks starting with a brief overview of the basics of radiolocation techniques and then look at some of the most well-known commercial positioning techniques and localization algorithms. We then concentrate on the application of the Fastmap (FM) algorithm in the field of wireless sensor localization. Our first contribution in this thesis is the mathematical analysis of the FM algorithm in terms of the mean squared error (MSE) of the coordinate estimate under a multiplicative noise model followed by the optimum placement of anchor nodes. The algorithm is compared to Linear Least Squares (LLS) algorithm, which is well known and has a similar complexity to that of FM. Another contribution is proposing the angle-projected FM algorithm for wireless sensor nodes localization in order to enhance the connectivity of the network and the overall performance. A comprehensive study and mathematical analysis in terms of the MSE for this algorithm is presented and it is also compared with the original FM algorithm. We also propose a weighted Fastmap (WFM) algorithm in which more than one pair of anchor nodes is used to evaluate the first coordinate (i.e., x-coordinate) of the unknown nodes in order to reduce the effect of error dependency in the y-coordinate estimation. (In the original FM algorithm only one pair of anchor nodes was employed.) The optimal WFM weights are determined via (constrained) minimization of the MSE of the estimated node coordinates. A simplification of the WFM is also introduced, called the averaged FM (AFM), where complexity is reduced at the expense of degradation in the overall WFM performance. Both the WFM and AFM exhibit improved performance over the original FM algorithm. Finally, an unbiased version of the WFM, AFM and FM is presented in which an estimate of the bias term is removed to improve the overall MSE performance. The effect of this modification on the algorithms' performance is then analysed and discussed.
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Sheridan, Martin. "Development of novel UV-activated irreversible colourimetric indicators." Thesis, University of Strathclyde, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.488535.
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Research into chemical sensors, and in particular colourimetric sensors, is an area of increasing interest. The instant access to important chemical information that such devices can bring is their most attractive feature. The aim of this project has been to develop such colourimetric indicators and to research their behaviour in detail such that their response to different environments can be known, and their formulation altered to suit the application.
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Schuller, Timothy Adam. "Gallium nitride sensor devices fabrication techniques and characterisation." Thesis, University of Bristol, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.549688.
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A saccharide sensor was fabricated using an AlGaN/GaN heterostructure structure and a boronic-acid containing receptor. Parallel to this, photoelectrochemical (PEC) etching of Gallium Nitride (GaN) was employed both as a nanostructuring technique and as a method of rapid dislocation density enumeration. The device fabrication techniques necessary for the development of devices based on n-type GaN and its alloys were successfully implemented. A robust photolithographic mask capable of producing a variety of transistor and sensor structures was designed and fabricated. Surface Charge Lithography (SCL) was studied and implemented as a technique for the nanostructuring of n-type GaN. In contrast to previous work (where patterns with feature sizes down to 100nm were created¹), several shortcomings of the technique were noted and subsequently investigated: a failure to achieve the intended minimum feature size; elongation of features in the direction of FIB instrument rastering; and the loss of thin features perpendicular to the rastering direction. A pattern design scheme to overcome these shortcomings was proposed along with experimental improvements expected to alleviate such issues. A novel receptor molecule employing a phenylboronic acid (BAT) was synthesised and used to functionalise an AlGaN/GaN FET device, thereby creating an electronic saccharide sensor device. The response of the sensor to a panel of saccharides (fructose, galactose and glucose) was investigated, with the order of response confirming previous findings (decreasing from fructose to galactose to glucose). The device was found to have good stability prior to failure, indicating that this type of sensor device shows a great deal of potential for wider use. PEC etching was used as a technique for determining the dislocation density in two distinct GaN on sapphire structures with thick AlN buffer layers. The SRI sample (100nm of GaN with 500nm of AlN) had a dislocation density of 1.9±O.2xl0⁹cm-², while the SH2 sample (500nm of GaN with lOOnm of AIN) had approximately twice this density, at 3.8±O.2xl0⁹cm-². The differences are thought to primarily arise from the difference in AlN thickness.
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Xu, Zhou. "On-line test of micro & nano systems." Thesis, Lancaster University, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.651304.
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Online test is a technology that has great importance and value in many applications. It provides unique benefit of real-time condition monitoring, based on which early warning of system failure or degradation and potentially system self-repair can be achieved to avoid more significant impact. In the context of on-line test, embedded off-line test is still a challenging issue for MEMS device, mainly due to their micro scale and what is typically multi energy domain functionality. There are very limited methods to observe and characterize the MEMS components under test, especially for the dynamic behavior. It is also in general more difficult to verify their performance under real working conditions. This work attempts to deliver real online test solutions and methodologies which can be adapted to wide range of MEMS devices. Novel techniques of Bias-Superposition and Multi-Mode Sensing are conceived and engineered with due consideration of the availability of on board resources (e.g. signal processing power) and design/cost overhead. The proposed techniques are demonstrated on two existing MEMS systems: a capacitive MEMS accelerometer and a resistive MEMS based conductance sensor. The concepts are further studied through the design of a piezoresistive multi-functional humidity/pressure sensor. By developing the theoretical model and applying the proposed methodologies on these different structures and applications, this work pushed the State-of-the-Art of micro & nano system's online test in three areas: firstly the work potentially enabled many existing electrical induced off-line test so lutions for MEMS systems to be transfonned to on-line; secondly an on-line test solution for electro-chemical microsystems has been conceived which by traditional methods is difficu lt to implement; last but not least the work advanced from on-l ine test to fault-to lerance within NJEMS sensor systems through resilience of the sensor network.
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Darbari, Faisal. "Wireless channel modelling for specknet." Thesis, University of Strathclyde, 2008. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=21973.
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A wireless sensor network (WSN) consists of spatially distributed autonomous devices using sensors to cooperatively monitor physical or environmental conditions, such as pressure, temperature, sound, vibration or motion at different locations. The development of wireless sensor networks was originally motivated by military applications such as battlefield surveillance. However, wireless sensor retworks are now used in many commercial applications, including environment and habitat monitoring, healthcare applications, home automation, and traffic control. The physical size of these devices is shrinking due to advances in semiconductor technology. The main challenge is to produce low cost and miniature sensor nodes. Energy is the scarcest resource for these nodes as it determines the WSN lifetime. Since these nodes will be deployed close together to form a dense wireless network the received signaI to noise ratio at any instant of time not only depends on physical channel (i. e. path loss and fading) but also on various design parameters like CSMA/CA inhibition threshold, polarization, deployment strategy and node density. This thesis characterises the propagation channel for miniature wireless nodes. A characterization of the short range (<10cm), narrowband, wireless channel, appropriate to a dense network of wireless transceivers operating in the 2.4 GHz ISM band, is presented. Transmission loss measurements have been made in the laboratory at 2.45 GHz and a fading model derived. Aggregate interference due to neighboring carrier-sense-multiple-access (CSMA) nodes has been calculated. The resulting dependence of signl-to-interference ratio (SIR) on node density is presented to allow density dimensioning. Cumulative distributions of SIR have been used to establish performance statistics for example modulation and detection schemes. A simulation model has been developed to characterise the physical link experienced by these networks.
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Kinnell, Peter Ken. "The development of selective strain coupling structures for a novel MEMS resonant pressure sensor." Thesis, University of Birmingham, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.422766.
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This thesis proposes a novel form of MEMS (micro electro mechanical system) resonant pressure sensor. The sensor incorporates a MEMS silicon resonator that is coupled to a macro scale metallic diaphragm. The combination of a large metallic diaphragm with a micro engineered MEMS resonator required an innovative selective strain coupling structure to be designed. Without the proposed coupling structure, unwanted packaging or thermally induced strain would severely degrade sensor performance, resulting in resonator misalignment, or unwanted strain loading. The feasibility of the proposed device is investigated though analysis and characterisation work performed on a prototype resonator, and a prototype selective coupling structure. These devices allowed fabrication processes to be developed, and their predicted performance to be verified. The prototype resonator demonstrated high quality factors of 28,000 - 30,000 in a vacuum, and resonant frequencies within 10% of modelled predictions. The selective coupling structure was shown to provide a reduction of resonator misalignment of 100: 1, while providing selective strain coupling of 900:1. Following this a fabrication route for producing the fully integrated resonator and selectively coupling structure was developed. This device was electrically tested to determine its resonant characteristics, and quality factors greater that 40,000 were demonstrated.
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Zhang, Haiyan. "Development of a novel, functional quantum dot-DNA/aptamer sensing technology." Thesis, University of Leeds, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.658610.
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Aptamers are short single-stranded DNA or RNA oligonucleotides artificially selected against specific targets. They exhibit high target binding affinity and exquisite specificity, making them very useful in developing biosensors for a wide range of targets, such as proteins, peptides, amino acids, drugs, metal ions and even whole cells. While fluorescent semiconductor nanocrystals, also known as quantum dots (QDs), have unique size-dependent, bright and extremely photo-stable fluorescence that make them as excellent fluorescent labels for biological imaging, sensing, cell tracking/trafficking and diagnostics. Their unique optical properties (broad absorption and narrow symmetric emission) are well-suited for FRET (fluorescence resonance energy transfer) based sensing applications. By combining the advance properties of both aptamers and QDs, this project aims to develop a sensitive, specific and robust aD-DNAlaptamer FRET based biosensing technology that can be used for rapid biosensing, diagnostics and environmental monitoring. A major hurdle here is the preparation of a compact, stable and water-soluble QD-bioconjugate that can effectively resist non-specific adsorption because FRET efficiency (E) decreases dramatically with the increasing donor-acceptor distance. Hence for high sensitivity, a compact QD-bioconjugate structure is essential. In this regard, a series of highly fluorescent, water-soluble CdSe/ZnS aDs were prepared first by ligand exchange with hydrophilic thiolated ligands, such as dihydrolipoic acid (DHLA), glutathione (GSH), dihydrolipoic acid-polyethyleneglycol (DHLAPEG600) derivatives. These QDs exhibited high fluorescence quantum yields (QYs, 6-30%), comparable to commercial water-soluble aDs (ca. 30%), but having significantly smaller hydrodynamic diameters «10 v.s. > 25 nm). Building upon these, three different QD-DNA aptamer sensing systems have been developed successfully: (1) A simple self-assembled aD-DNA system: I have found that thiolated DNA can self-assemble onto DHLA capped QDs to form compact, functional QD-DNA conjugates with small donor-acceptor distances, producing efficient FRET (E > 70%) at a relatively low (target: QD) copy number of 6:1. The resulting self-assembled aD-DNA (aptamer) conjugate has been used to detect low nM levels of labelled DNA target via QD sensitised dye FRET signal. Moreover, it has been successfully used for detection of nM level of a protein target via the encoded DNA aptamer sequence, although its specificity and stability still need further improvement. (2) A more stable and sensitive aD-dual-donor FRET sensing system based on an amine-modified DNA covalently coupled to a glutathione capped aD combined with the use of specific ethidium bromide (EB) intercalation in hybridized DNA duplex. As a result, both the aD and intercalated EBs can FRET to the dye acceptor appended to the complementary DNA, leading to significantly improved the overall FRET efficiency E, and hence sensitivity in both DNA and protein target detection down to pM level. (3) A Cu-free "clicked", robust, and_specific QD-DNA aptamer sensor. A compact, functional aD-DNA conjugate was prepared via the Cu-free "click chemistry" (CFCC) between a dihydrolipoic acid -polyethylene glycol-azide (DHLA-PEG600-N3) capped aD and a cyclooctyne modified DNA. The resulting QD-DNA conjugate is highly stable in biological buffer, effectively resisting nonspecific absorption, displaying a relatively small size (hydrodynamic radius - 5 nm) and retaining almost the native ay of the parent aD. Moreover, the CFCC based DNA conjugation method is also highly efficient, leading to high DNA loading (- 15-30 DNA strands per aD is readily achieved). This system is well-suited for robust biosensing: it can quantitate pM level of complementary DNA targets with SNP (singlenucleotide polymorphism) discrimination ability in complex media, e.g. 10% human serum. It can also detect pM level of a specific protein via the encoded DNA aptamer sequence. Compared with these approaches, the self-assembled system is the most convenient to prepare, but it has the least stability and cannot resist nonspecific absorption. The dual-donor FRET sensing system shows some enhancement on the stability and resisting nonspecific absorption, but it still cannot work in complex media, such as serum. The CFCC clicked QD-DNA aptamer sensor shows the highest stability, specificity and assay robustness, and can effectively work in clinical media. It can be readily extended to design sensors against other targets by simply clicking on specific aptamer sequences against such targets. Because the CFCC clicked QD-DNAlaptamer sensor shows high stability, specificity, robustness· and sensitivity, it may have a wide range of biosensing and diagnostic applications
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Makhnovskiy, Dmitriy. "Diagonal and off-diagonal magneto-impedance in ferromagnetic microwires and thin films." Thesis, University of Plymouth, 2003. http://hdl.handle.net/10026.1/2322.
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The discovery of the giant magneto-impedance (GMI) effect in 1994 had a strong impact on the development of micro magnetic sensors. In certain soft magnetic materials, such as composites of amorphous thin wires, the magneto-impedance change (MI ratio) is in the range of 50-100% in the MHz frequency band for external magnetic fields of few Oe. Special thin-film structures have been proposed to provide the MI effect in miniature elements. In the present work, the concept of the magneto-impedance matrix has been elaborated, which enables the explanation of variety of MI field characteristics in wires and films from the common point of view. The fabrication technologies of the narrow thin film MI samples with different structures also were developed, including layered films and films integrated with a helical planar microcoil. The experimental technique employed in the work allowed us to measure all components of the total magneto-impedance matrix that came as the first verification of the matrix concept of the magneto-impedance. Different methods of getting the asymmetrical and antisymmetrical magneto-impedance behaviours were proposed demonstrating a great success of the impedance matrix concept. In the case of a simple transverse magnetic anisotropy, the diagonal components of the magneto-impedance matrix are symmetric and the off-diagonal components are antisymmetrical with respect to the de longitudinal magnetic field. The asymmetry in MI behaviour can be related to either a certain asymmetric arrangement of the dc magnetic configuration or a contribution to the measured voltage due to the ac cross-magnetisation process, represented by the off-diagonal component. The first case is realised in the wire and film having the helical or crossed anisotropies respectively, which are subjected to an ac current superposed with a de bias current. In the other approach, the asymmetric voltage response can be obtained by applying the ac current in series through the MI element (wire or film) and the small coil surrounded it. No helical anisotropy is required in this case. These kinds of asymmetrical MI are especially important for developing auto-biased linear MI sensors. The thin film with the integrated planar microcoil allowed us to measure the off-diagonal impedance in the sandwiched film. Results obtained for MI in thin films open up the perspective directions for the integrated MI sensors. The applications of the MI effect are not limited only by magnetic sensor technology. In this work, a new type of tuneable composite materials was proposed, the effective microwave permittivity (dielectric constant) of which depends on the de external magnetic field applied to the composite as a whole. The composite consists of the short pieces of ferromagnetic wires embedded into a dielectric matrix. The composite sample can be fabricated in the form of thin slab with thickness less than 1 millimetre. The short wire inclusions play the role of "the elementary scatterers", when the electromagnetic wave irradiates the composite and induces an electrical dipole moment in each inclusion. These induced dipole moments form the dipole response of the composite, which can be characterised by some effective permittivity. The field dependence of the effective permittivity arises from a high field sensitivity of the ac surface impedance of a ferromagnetic wire. In the vicinity of the antenna resonance (related with the short wire inclusions) any variations in the magneto-impedance of wires result in large changes of the effective permittivity. Therefore, this composite demonstrates both the tuneable and resonance properties (selective absorption). Thus, we have demonstrated a possibility of using the MI effect to design field-controlled composites and band-gap structures. A number of applications can be proposed, including selective microwave coatings with the field-dependent reflection/transmission coefficients and selective tuneable waveguides where the composite material may be used as an additional field-dependent coating. In addition, in the final chapter of future work we will take a quick look at tuneable composites with other microstructures and methods of the excitation.
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Rigg, Euan. "Fibre Bragg grating sensors for component shape change measurement." Thesis, Heriot-Watt University, 2004. http://hdl.handle.net/10399/247.
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Bach, Thomas William. "Design, modelling and applications of capacitive sensor arrays." Thesis, University of Sussex, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.436252.
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Smith, Paul David. "MEMS sensors exploiting the squeeze-film damping effect." Thesis, University of Sussex, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.430371.
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Tansley, Steven James. "The dynamics of an acoustically excited vibratory rate sensor." Thesis, University of Nottingham, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.407036.
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Wong, Seck Jiong. "Thermoelastic damping in MEMS ring resonators." Thesis, University of Nottingham, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.431849.
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St, Ville Lyndell P. "A data-stream management infrastructure for mutually unaware applications accessing shared-sensor networks." Thesis, University of Glasgow, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.414064.
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Jackson, Richard James. "Engineering nanostructures for biological sensor surfaces." Thesis, University of Newcastle Upon Tyne, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.430773.
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Merrifield, Jonathan David. "Development of novel sensors for biologically active molecules based on the selective modification of supported phospholipid monolayers." Thesis, University of Leeds, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.446053.
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Yates, James W. T. "Black box and mechanistic modelling of electronic nose systems." Thesis, University of Warwick, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.413428.
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Dutta, Ritaban. "A novel approach to analysing electronic nose data : object oriented expert system." Thesis, University of Warwick, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.406818.
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Brook, Rosie Annalise. "Porphyrin guest-host langmuir-blodgett matrices for toxic gas sensing." Thesis, University of Sheffield, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.419620.
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O'Leary, Richard Lewis. "An investigation into the passive materials utilised within the construction of piezoelectric composite transducers." Thesis, University of Strathclyde, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.405537.
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Campbell, Alexander. "Chemical sensors based on fibre optics and fluorescence measurements." Thesis, University of Strathclyde, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.400313.
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TrogeÌ, Alexandre. "A new range of ultrasonic transducers." Thesis, University of Strathclyde, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.438139.
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Mandal, Jharna. "Fibre laser development for sensor applications." Thesis, City University London, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.435942.
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Dunford, Timothy Peter. "An investigation into the use of mesoporous Pd films and silicon microfabricated microhotplates as a methane sensor." Thesis, University of Southampton, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.438679.
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Pavlou, Alexandros K. "Novel intelligent gas-sensing in diagnosis of infectious diseases." Thesis, Cranfield University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.399121.
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Landi, S. "Reactive ion etching techniques for uncooled pyroelectric detectors." Thesis, Cranfield University, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.423086.
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Fisher, Paul Conway. "Biologically inspired robotic search strategies in chemical fields." Thesis, University of Portsmouth, 2008. https://researchportal.port.ac.uk/portal/en/theses/biologically-inspired-robotic-search-strategies-in-chemical-fields(918d7741-f414-443e-8cea-91177fccb5aa).html.
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Ibrahim, Norahim. "Sensor innovations based on modified carbon electrodes." Thesis, University of Bath, 2012. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.557802.
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This thesis describes experimental work on electrochemical sensing mechanisms. Chapter 1 and Chapter 2 provide an introduction to electrochemical and surface science techniques as well as nano-carbon materials which are of interest in electroanalysis and sensing. Chapter 3 and Chapter 4 focus on electrochemical processes at liquid | liquid | electrode triple phase boundary systems. In Chapter 3 the electrochemical behaviour of CoPc (cobalt phthalocyanine) dissolved into an organic water –insoluble liquid and deposited as microdroplets on a graphite electrode is studied. Both cation and anion transfer are observed at the liquid | liquid phase boundary. Chapter 4 describes redox processes of a highly hydrophobic anthraquinone derivative where preferential transfer of protons and pH sensitivity are observed. Both systems, CoPc and anthraquinone derivative, are investigated towards CO2 sensitivity. In Chapter 3 and 4 graphite electrodes are employed, but in Chapter 5 graphitic carbon nanoaprticles are employed with a surface functionalisation to provide binding capability to DNA fragments. Layer-by-layer deposition of DNA-carbon nanoparticle composite film electrodes is demonstrated and the electrochemical properties of the films are investigated. A novel type of DNA hybridisation sensing mechanism based on a nano-gap generator – collector electrode system is proposed. Chapters 6 and 7 are dedicated to gas sensing with a novel electrochemical system based on ionomer spheres in contact to the working electrode. In Chapter 6 Dowex ionomer particles are impregnated with carbon nanoparticles which are functionalised with DOPA to provide redox activity and Faradaic current responses. The effect of ionomer type and gas composition is studied. In Chapter 7 Prussian blue nanoparticles are immobilised onto the ionomer particle surface to provide a sensing system with peroxide sensitivity. Overall, this thesis contributes to sensing of bio-molecules and of gases. By introducing new types of interfaces (triple phase boundary, ionomer contacts, carbon nanoparticle redox systems) it is shown that sensitivity and selectivity can be tailored. In future these types of sensor prototypes could be further developed for specific applications.
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Tan, T. H. "Silicon piezoresistors for MEMS pressure sensor applications." Thesis, Queen's University Belfast, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.677842.
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Silicon based micromachining technology enables the realization of high performance micro electromechanical systems (MEMS) including a range of physical and environmental sensors. Pressure sensors are used for a wide range of monitoring and control applications, e.g. environmental, industrial, aircraft, automotive. Monitoring of vehicle tyre pressures offers benefits such as improved safety, fuel economy, and tyre life. Micromachined pressure sensors are used at present, but require further research to improve their performance in terms of size, power consumption and manufacturing cost. This thesis has reviews pressure sensor technology and new developments in this area. A comparison of existing and potential future sensing mechanisms has been undertaken and identified as silicon piezoresistors. The focus of the research is motivated by the recently discovered enhanced piezoresistive effect in silicon nanowires where sensitivity can be increased by decreasing the dimension of nanowire. This thesis investigates the piezoresistive effect in p-type <110> silicon nanowires, fabricated using top down approach. It is found that the piezoresistive effect increases when the nanowire width is reduced below 400nm. Compared with micrometre sized piezoresistors, silicon nanowires have produced up to 100% enhancement. In addition, measurements indicate that the temperature coefficient of resistance (TCR) of silicon nanowire has improved with up to 40% decrease in TCR. The improvement in these two areas will be beneficial for the development of new MEMS pressure sensors. COMSOL is employed to simulate the piezoresistance effect in p-type <110> silicon for a range of doping concentrations. Simulation results demonstrate a similar trend to experimental results and publication data and show that the piezoresistance effect decreases as the doping concentration increases.
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Zhang, Chi. "Fibre Bragg gratings in polymer optical fibre for applications in sensing." Thesis, Aston University, 2012. http://publications.aston.ac.uk/16428/.
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This thesis presents the potential sensing applications of fibre Bragg gratings in polymer optical fibres. Fibre Bragg gratings are fabricated in different kinds of polymer optical fibres, including Poly methyl methacrylate (PMMA) and TOPAS cyclic olefin copolymer based microstructured polymer optical fibres and PMMA based step-index photosensitive polymer optical fibre, using the 325nm continuous wave ultraviolet laser and phase mask technique. The thermal response of fabricated microstructured polymer optical fibre Bragg gratings has been characterized. The PMMA based single mode microstructured polymer optical fibre Bragg gratings exhibit negative non-linear Bragg wavelength shift with temperature, including a quasi-linear region. The thermal sensitivity of such Bragg gratings in the linear region is up to -97pm/°C. A permanent shift in the grating wavelength at room temperature is observed when such gratings are heated above a threshold temperature which can be extended by annealing the fibre before grating inscription. The largest positive Bragg wavelength shift with temperature in transmission is observed in TOPAS based few moded microstructured polymer optical fibre Bragg gratings and the measured temperature sensitivity is 250±0.5pm/°C. Gluing method is developed to maintain stable optical coupling between PMMA based single mode step index polymer optical fibre Bragg gratings and single mode step index silica optical fibre. Being benefit from this success, polymer optical fibre Bragg gratings are able to be characterised for their temperature, humidity and strain sensitivity, which are -48.2±1pm/°C, 38.3±0.5pm per %RH and 1.33±0.04 pm/µε respectively. These sensitivities have been utilised to achieve several applications. The strain sensitivity of step index polymer optical fibre Bragg grating devices has been exploited in the potential application of the strain condition monitoring of heavy textiles and when being attached to textile specimens with certain type of adhesives. These polymer fibre Bragg grating devices show better strain transfer and lower structure reinforcement than silica optical fibre Bragg grating devices. The humidity sensitivity of step index polymer optical fibre Bragg grating devices is applied to detecting water in jet fuel and is proved to be able to measure water content of less than 20 ppm in Jet fuel. A simultaneous temperature and humidity sensor is also made by attaching a polymer fibre Bragg grating to a silica optical fibre Bragg grating and it shows better humidity measurement accuracy than that of electronic competitors.
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Yamazaki, Miki. "Novel technologies for high sensitivity analyte detection." Thesis, Imperial College London, 2012. http://hdl.handle.net/10044/1/9999.
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Microfluidic devices are attracting interest for point-of-care diagnostics due to their low unit cost, low reagent and sample usage, fast analysis times and portability. Fluorescence is the most widely used detection method in microfluidics due to its high sensitivity, excellent dynamic range, ease of implementation and non-invasive nature. Fluorescence detection has accordingly been widely used for the interrogation of microfluidic devices, with the majority of reports to date having used non-integrated laser excitation sources coupled with off-chip optics and photodetectors. For point-of-care applications, there is a growing need for self-contained systems which incorporate the microfluidic chip and all associated optical components into a compact, low-cost package. Highly compact systems of this kind would eliminate the need for expensive dedicated bench-top instrumentation. As such they would find multiple uses in the home, ambulance and GP’s surgery, where their ability to provide immediate and/or frequent testing would enable faster, more responsive and ultimately more successful treatment. Work undertaken in this thesis focuses on developing highly sensitive analyte detection systems that would enable the use of cheap optical and electronic components. To accomplish this, two separate methods, based on optical filters and time-gated detection of phosphorescent polymer beads, were investigated. We describe a simple technique for fabricating non-emissive colour filters based on the sensitisation of a highly porous nanostructured metal-oxide film with a monolayer of dye molecules. The resultant filters exhibit much less autofluorescence than conventional colour filters, and are a viable low cost alternative to interference filters. In separate work Ru(dpp)3-doped polystyrene/bisphenol A diglycidyl ether polymer phosphorescent beads developed by Dr. Edwards (Imperial College London) were used to demonstrate the feasibility of highly sensitive of low-cost time-gated detection. This method was applied to a simple biotin assay to show their bio-assay applicability.
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Malleson, Charles D. "Dynamic scene modelling and representation from video and depth." Thesis, University of Surrey, 2016. http://epubs.surrey.ac.uk/809990/.
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Recent advances in sensor technology have introduced low-cost video+depth sensors, such as the Microsoft Kinect, which enable simultaneous acquisition of colour and depth images at video rates. The aim of this research is to investigate representations which support integration of noisy, partial surface measurements over time to form more complete, temporally coherent models of dynamic scenes with enhanced detail and reduced noise. The initial focus of this work is on the restricted case of rigid geometry for which online GPU-accelerated volumetric fusion is implemented and tested. An alternative fusion approach based on dense surface elements (surfels) is also explored and compared to the volumetric approach. As a first step towards handling non-rigid scenes, the static volumetric approach is extended to treat articulated (semi-rigid) geometry with a focus on humans. The human body is segmented into piece-wise rigid volumetric parts and part tracking is aided by depth-based skeletal motion data. To address scenes containing more general non-rigid geometry beyond people and isolated rigid shapes, a more flexible approach is required. A piece-wise modelling approach using a sparse surfel graph and repeated alternation between part segmentation, motion and shape estimation is proposed. The method is designed to incorporate methods for noise reduction and handling of missing data. Finally, a hybrid approach is proposed which leverages the advantages of the surfel graph segmentation and coarse surface modelling with the higher-resolution surface reconstruction capability of volumetric fusion. The hybrid method is able to produce a seamless skinned mesh structure to efficiently represent a temporally consistent dynamic scene. The hybrid framework can be considered a unification of rigid and non-rigid reconstruction techniques, for which static scenes are a special case. It allows arbitrary dynamic scenes to be efficiently represented with enhanced levels of detail and completeness where possible, but gracefully falls back to raw measurements where no structure can be inferred. The representation is shown to facilitate creative manipulation of real scene data which would previously require more complex capture setups or extensive manual processing.
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Marty, Pierre Noel. "Modeling of ultrasonic guided wave field generated by piezoelectric transducers." Thesis, Imperial College London, 2002. http://hdl.handle.net/10044/1/7222.
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Mills, Daniel W. "Towards a commerical microelectrode array based sensor for improved chlorine detection." Thesis, Cranfield University, 2005. http://dspace.lib.cranfield.ac.uk/handle/1826/4177.
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The commercial development of a disposable aqueous chlorine sensor based on a novel microelectrode array fabrication process is described. Non-conducting poly(o-phenylenediamine) films are firstly used to passivate conductive surfaces. Ultrasonic ablation of passivated electrode assemblies then results in the formation of a plurality of wells to expose the underlying conductive substrate, thereby forming a microelectrode array. Microelectrode arrays produced in this manner can be exploited within many electrochemical sensing applications; however, portable aqueous chlorine detection has been selected by Microarray Limited (the industrial sponsors of this project) as a primary vehicle for launching its generic production technology. The scale of microelectrode array production has been extended from that of individual gold sputtercoated glass slide electrodes - to the simultaneous production of hundreds of low-cost screen printed carbon-ink based sensors. A focus has been directed at all stages towards permitting the cost-effective large-scale mass production of sensors with a view to challenging existing portable aqueous chlorine measurement technologies both in terms of performance and unit cost. Based on volume batches of 250,000, it has been calculated that Microarray Limited sensors can be manufactured for a unit cost of approximately 2.5 pence, sufficiently low to provide scope for a competitive yet profitable sale price. The Microarray Limited aqueous chlorine detection system has improved the limit of detection from 0.01 ppm to 0.005 ppm total chlorine without sacrificing accuracy. Furthermore, this novel approach to aqueous chlorine detection offers numerous key benefits to the customer including reduced testing time, a more straightforward operation and the elimination of harmful reagents. Product development has been described from an initial concept through to a pre-production phase. The development of an innovative generic sensor packaging technology is also described.
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Mann, Dominic Peter. "Zeolite modified metal oxides for gas sensing." Thesis, University College London (University of London), 2005. http://discovery.ucl.ac.uk/1445742/.
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A novel method of improving the selectivity of metal oxide gas sensors has been developed by using catalytically active molecular sieve materials. They have been successfully introduced into a proprietary sensor array and a commercially available electronic nose. The cracking patterns of various organic compound groups including alkanes, aromatics and flavours over transition metal exchanged zeolites (ZSM-5, zeolite Y, and zeolite p) have been measured using a zeolite bed/GC/MS experimental set-up within a temperature range of 200 C to 400 C. The findings have been successfully translated for the use of the zeolites as filter technology on chromium titanium oxide (CTO) sensors for the purposes of selective gas sensing. Studies have been carried out regarding the effects of metal loading, zeolite type, material fabrication techniques and operating temperature with regards to catalytic activity and selectivity. Variations in activity due to alkane chain length have been related to the ability of the molecule to enter the zeolite cavity, the quantity of supported metal complexes and their oxidation state in the zeolite pores. The composite sensors utilising the novel zeolite materials have been used in a custom built sensor rig that houses 3 dual electrode sensors and can measure real time responses of these sensors to an introduced headspace generated from organic liquids. The response data have been utilised in a statistical software package (SPSS 12.0) to rationalise sensor discriminatory behaviour to various compound groups. The zeolite coated CTO sensors have also been tested in a commercial electronic nose array which has provided enhanced discrimination as compared to a standard CTO sensor array for a number of active and potential commercial applications mainly involving complex flavour compound mixtures.
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Олійник, Ольга Юріївна. "Науково-методологічні засади віброчастотного контролю технологічних параметрів в умовах вібрації." Thesis, Національний технічний університет "Харківський політехнічний інститут", 2019. http://repository.kpi.kharkov.ua/handle/KhPI-Press/42234.
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Дисертація на здобуття наукового ступеня доктора технічних наук за спеціальністю 05.11.13 – прилади і методи контролю та визначення складу речовин» ‒ Державний вищий навчальний заклад «Український державний хіміко-технологічний університет», МОН України, Дніпро, 2019. Дисертація присвячена вирішенню науково-прикладної проблеми підвищення достовірності контролю технологічних параметрів (густини, в’язкості, зусилля (тиску)) в умовах вібрації за рахунок розроблення нових математичних моделей та методів визначення технологічних параметрів, застосування нових багатопараметричних віброчастотних перетворювачів з універсальною характеристикою та змінним співвідношенням сигнал-шум, розробки програмних засобів фільтрації зашумленої вимірювальної інформації з невідомими законами розподілу. Розроблено віброчастотний метод контролю та вимірювання густини, в’язкості, зусилля (тиску) газорідинних середовищ у виробничих умовах, який реалізується за допомогою віброчастотного вимірювального перетворювача з трубчатим, циліндричним резонатором у якості якого може використовуватись частина технологічного апарату, отримано математичні моделі амплітудно- частотних характеристик технологічних параметрів в апаратах різного типа конструкції. Розроблено теоретичні основи проектування неметалевих трубчатих проточних резонаторів з широкою сферою застосування. Розроблено багатофункціональний віброчастотний перетворювач для вимірювання густини, в’язкості, зусилля (тиску) з циліндричним резонатором, який має універсальну характеристику. Виконані дослідницькі роботи щодо попередньої ідентифікації законів розподілу, розроблено алгоритм фільтрації Калмана вимірювальної інформації з підвищеними завадами та структура багатопараметричної системи контролю технологічних параметрів з системою діагностики форми коливань резонатора; вдосконалено пристрій для ідентифікації активного стану оператора. Здійснені впровадження інженерних розробок дисертаційної роботи на провідних підприємствах Дніпра та за кордоном.Thesis for a degree of Doctor of Science (Technology), Specialty 05.11.13 – Instruments and Methods of Control and compounds` composition determination. – State Higher Educational Institution «Ukrainian State Chemical-Technological University», Ministry of Education and Science of Ukraine, Dnipro, 2019. The dissertation is devoted to solving the scientific and applied problem of increasing the reliability of the control of technological parameters (density, viscosity, force (pressure)) in a production environment through the development of new mathematical models and methods for determining technological parameters from the amplitude-frequency characteristics of the oscillatory environment of apparatuses, the use of new multiparameter vibration frequency converters with a universal characteristic and variable signal-to-noise ratio, as well as software development STV filtering noisy measurement information with unknown distribution laws. A vibration frequency method has been developed for monitoring and measuring the density, viscosity, force (pressure) of gas-liquid media under industrial conditions using a measuring transducer with a tubular, cylindrical resonator, mathematical models of the amplitude-frequency characteristics of technological parameters in devices of various designs are obtained. Theoretical foundations have been developed for the design of non-metallic tubular flow resonators with a wide scope. A multifunctional vibration frequency converter has been developed for measuring density, viscosity, force (pressure) with a cylindrical resonator, which has a universal characteristic. Research work on the identification of distribution laws has been completed, an Kalman filtering algorithm has been developed for measuring information with increased noise, and the structure of a multidimensional control system for technological parameters with a system for diagnosing the shape of resonator vibrations; improved device for identifying the active state of the operator. Implementation of engineering developments of the thesis was carried out at the leading enterprises of the Dnieper and abroad.
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van, Well Ben Russell. "A portable laser system for the remote detection of methane gas." Thesis, University of Glasgow, 2006. http://theses.gla.ac.uk/6145/.
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We have developed an open-path hand-held gas detector incorporating a distributed feedback InGaAs laser diode at 1.65μm. Incorporated into a hand-held transceiver unit, the emitted laser beam is backscattered from nearby surfaces, collected and focussed onto an amplified InGaAs detector using a 150mm diameter plastic Presnel lens. At ranges of 4-5metres, a typical backscattered signal is tens of nanowatts of laser light. Applying second derivative wavelength modulation spectroscopy (WMS) gives a sensitivity to methane of better than 10 parts per million over a one metre path length. Chapter 1 gives background information on existing detection methods, and explains why we chose to implement WMS. Chapter 2 discusses the various models created to justify the decision to use WMS. It also describes techniques used to help visualise escaping gas. Chapter 3 discusses the various stages of design and build of the actual prototypes, starting with a laboratory based prototype and finishing with a fully portable technology demonstrator. Chapter 4 give details of the laboratory testing undertaken in order to characterise and benchmark the system performance. Chapter 5 is concerned with the design and construction of an additional add-on scanning platform which scans the pointer instrument in order to build a 2-dimensional image of the gas escape. Chapter 6 mirrors chapter 3 in format, and discusses the various field-trials where the instruments were tested in representative conditions. Finally Chapter 7 highlights the work performed in developing a pre-production prototype and advertising the instrument to a wider market.
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Molloy, A. J. "Force sensing for measuring human body movement." Thesis, Aston University, 2006. http://publications.aston.ac.uk/15354/.
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The research developed in this thesis explores the sensing and inference of human movement in a dynamic way, as opposed to conventional measurement systems, that are only concerned with discrete evaluations of stimuli in sequential time. Typically, conventional approaches are used to infer the dynamic movement of the body; such as vision and motion tracking devices, with either a human diagnosis or complex image processing algorithm to classify the movement. This research is therefore the first of its kind to attempt and provide a movement classifying algorithm through the use of minimal sensing points, with the application for this novel system, to classify human movement during a golf swing. There are two main categories of force sensing. Firstly, array-type systems consisting of many sensing elements, and are the most commonly researched and commercially available. Secondly, reduced force sensing element systems (RFSES) also known as distributive systems have only been recently exploited in the academic world. The fundamental difference between these systems is that array systems handle the data captured from each sensor as unique outputs and suffer the effects of resolution. The effect of resolution, is the error in the load position measurement between sensing elements, as the output is quantized in terms of position. This can be compared to a reduced sensor element system that maximises that data received through the coupling of data from a distribution of sensing points to describe the output in discrete time. Also this can be extended to a coupling of transients in the time domain to describe an activity or dynamic movement. It is the RFSES that is to be examined and exploited in the commercial sector due to its advantages over array-based approaches such as reduced design, computational complexity and cost.
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Tan, Su-Lim. "Smart chemical sensing microsystem : towards a nose-on-a-chip." Thesis, University of Warwick, 2005. http://wrap.warwick.ac.uk/61912/.
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The electronic nose is a rudimentary replica of the human olfactory system. However there has been considerable commercial interest in the use of electronic nose systems in application areas such as environmental, medical, security and food industry. In many ways the existing electronic nose systems are considerable inferior when compared to their biological counterparts, lacking in terms of discrimination capability, processing time and environmental adaptation. Here, the aim is to extract biological principles from the mammalian olfactory systems to create a new architecture in order to aid the implementation of a nose-on-a-chip system. The primary feature identified in this study was the nasal chromatography phenomena which may provide significant improvement by producing discriminatory spatio-temporal signals for electronic nose systems. In this project, two different but complimentary groups of systems have been designed and fabricated to investigate the feasibility of generating spatio-temporal signals. The first group of systems include the fast-nose (channel 10 cm x 500 μm2), proto-nose I (channel 1.2 m x 500 μm2) and II (channel 2.4 m x 500 μm2) systems that were build using discrete components. The fast-nose system was used to characterise the discrete sensors prior to use. The proto-nose systems, in many ways, resembles gas chromatography systems. Each proto-nose system consists of two microchannels (with and without coating) and 40 polymer-composite sensors of 10 different materials placed along it. The second group of systems include the hybrid-nose and the aVLSI-nose microsensor arrays assembled with microchannel packages of various lengths (5 cm, 32 cm, 7lcm, 240 cm) to form nose-on-a-chip systems. The hybrid-nose sensor array consists of 80 microsensors built on a 10 mm x 10 mm silicon substrate while the aVLSI-nose sensor array consists of 70 microsensors built on a 10 mm x 5 mm silicon substrate using standard CMOS process with smart integrated circuitries. The microchannel packages were fabricated using the Perfactory microstereolithography system. The most advanced microchannel package contains a 2.4 m x 500 J.lm2 microchannel with an external size of only 36 mm x 27 mm x 7 mm. The nose-on-a-chip system achieved miniaturisation and eliminates the need for any external processing circuitries while achieving the same capability of producing spatio-temporal signals. Using a custom-designed vapour test station and data acquisition electronics, these systems were evaluated with simple analytes and complex odours. The experimental results were in-line with the simulation results. On the coated proto-nose II system, a 25 s temporal delay was observed on the toluene vapour pulse compared to ethanol vapour pulse; this is significant compared to the uncoated system where no delay difference was obtained. Further testing with 8 analyte mixtures substantiated that spatio-temporal signals can be extracted from both the coated proto-nose and nose-on-a-chip (hybrid-nose sensor array with 2.4 m long microchannel) systems. This clearly demonstrates that these systems were capable of imitating certain characteristics of the biological olfactory system. Using only the temporal data, classification was performed with principal components analysis. The results reinforced that these additional temporal signals were useful to improve discrimination analysis which is not possible with any existing sensor-based electronic nose system. In addition, fast responding polymer-composite sensors were achieved exhibiting response times of less than 100 ms. Other biological characteristics relating to stereolfaction (two nostrils sniffing at different rates), sniffing rate (flow velocity) and duration (pulse width) were also investigated. The results converge with the biological observations that stereolfaction and sniffing at higher rate and duration improve discrimination. Last but not least, the characterisation of the smart circuitries on the aVLSI-nose show that it is possible to achieve better performance through the use of smart processing circuitries incorporating a novel DC-offset cancellation technique to amplify small sensor response with large baseline voltage. The results and theories presented in this study should provide useful contribution for designing a higher-performance electronic nose incorporating biological principles.
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Cowie, Barbara Mary. "Tactile sensing with fibre Bragg gratings and neural networks." Thesis, Aston University, 2008. http://publications.aston.ac.uk/15297/.
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Fibre Bragg grating sensors are usually expensive to interrogate, and part of this thesis describes a low cost interrogation system for a group of such devices which can be indefinitely scaled up for larger numbers of sensors without requiring an increasingly broadband light source. It incorporates inherent temperature correction and also uses fewer photodiodes than the number or sensors it interrogates, using neural networks to interpret the photodiode data. A novel sensing arrangement using an FBG grating encapsulated in a silicone polymer is presented. This sensor is capable of distinguishing between different surface profiles with ridges 0.5 to 1mm deep and 2mm pitch and either triangular, semicircular or square in profile. Early experiments using neural networks to distinguish between these profiles are also presented. The potential applications for tactile sensing systems incorporating fibre Bragg gratings and neural networks are explored.
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Georgoulas, Dimitrios. "An intelligent approach for deploying applications in WSN's." Thesis, Aston University, 2009. http://publications.aston.ac.uk/15307/.
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Wireless sensor networks have been identified as one of the key technologies for the 21st century. They consist of tiny devices with limited processing and power capabilities, called motes that can be deployed in large numbers of useful sensing capabilities. Even though, they are flexible and easy to deploy, there are a number of considerations when it comes to their fault tolerance, conserving energy and re-programmability that need to be addressed before we draw any substantial conclusions about the effectiveness of this technology. In order to overcome their limitations, we propose a middleware solution. The proposed scheme is composed based on two main methods. The first method involves the creation of a flexible communication protocol based on technologies such as Mobile Code/Agents and Linda-like tuple spaces. In this way, every node of the wireless sensor network will produce and process data based on what is the best for it but also for the group that it belongs too. The second method incorporates the above protocol in a middleware that will aim to bridge the gap between the application layer and low level constructs such as the physical layer of the wireless sensor network. A fault tolerant platform for deploying and monitoring applications in real time offers a number of possibilities for the end user giving him in parallel the freedom to experiment with various parameters, in an effort towards the deployed applications running in an energy efficient manner inside the network. The proposed scheme is evaluated through a number of trials aiming to test its merits under real time conditions and to identify its effectiveness against other similar approaches. Finally, parameters which determine the characteristics of the proposed scheme are also examined.
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Олійник, Ольга Юріївна. "Науково-методологічні засади віброчастотного контролю технологічних параметрів в умовах вібрації." Thesis, Національний технічний університет "Харківський політехнічний інститут", 2019. http://repository.kpi.kharkov.ua/handle/KhPI-Press/42235.
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Дисертація на здобуття наукового ступеня доктора технічних наук за спеціальністю 05.11.13 – «прилади і методи контролю та визначення складу речовин». ‒ Державний вищий навчальний заклад «Український державний хіміко-технологічний університет» Міністерства освіти і науки України, Дніпро, 2019. ‒ Національний технічний університет «Харківський політехнічний інститут» Міністерства освіти і науки України. Дисертація присвячена вирішенню науково-прикладної проблеми впідвищення достовірності контролю технологічних параметрів (густини, в’язкості, зусилля (тиску)) в умовах выбрації (технологічних апратах та обладнанні) за рахунок розроблення нових математичних моделей та методів визначення технологічних параметрів за амплітудно-частотними характеристиками коливального середовища апаратів, застосування нових багатопараметричних віброчастотних перетворювачів з універсальною характеристикою та змінним співвідношенням сигнал-шум, отриманих завдяки використанню автоколивальної системи зі стабільними характеристиками на першій гармоніці без застосування додаткових частотних фільтрів, розробки програмних засобів фільтрації зашумленої вимірювальної інформації з невідомими законами розподілу Проведено аналіз сучасних підходів до вимірювання технологічних параметрів (густини, в’язкості, зусилля (тиску) у виробничих умовах, що характеризуються підвищеною вібрацією, встановлені фактори, що вносять найсуттєвіший вплив на викривлення результатів вимірювання і створюють додаткові похибки, запропоновані методи компенсації впливу зазначених факторів. Існуючі методи неруйнівного контролю не задовольняють поставленим завданням, оскільки не дають можливості контролювати швидкоплинні технологічні процеси, а створення штучної коливальної системи не дає змогу контролювати амплітудно-частотні характеристики природної коливальної системи, що виникає в апараті. Вперше отримано математичні моделі статичних характеристик перетворення для розробленого віброчастотного методу вимірювання технологічних параметрів (густини, в’язкості, зусилля (тиску) в апаратах з природними коливальними системам для типу конструкції апаратів «труба», «циліндр» та для апаратів з барботажем та пульсацією середовища на основі гіпотез Сорокіна та Кірхгофа-Лява у виробничих умовах, що дозволяють визначати вказані параметри за амплітудно-частотними характеристиками природних коливальних систем у апаратах та зменшити динамічну похибку каналу вимірювання параметру більш ніж у 10 разів (0,012 %). Запропановано теоретичні основи проектування неметалевих трубчатих проточних резонаторів з широкою сферою застосування (вимірювання густини рідких і газоподібних середовищ, концентрації розчинів, температурного коефіцієнта, модуля пружності матеріалу) конструкція яких дозволяє підвищити точність вимірювання за рахунок регулювання активної частини резонатора з урахуванням жорсткості (піддатливості) типу кріплення і його розташування. Метод визначення частоти та форми коливань дозволяє 17% точніше визначати місця максимальних напружень між кріпленнями та одночасно зменшити вплив віброакустичний вплив трубопроводів на результат вимірювання амплитудно-частотних характеристик апарату.
Після розроблення і виготовлення дослідних зразків багатофункціонального віброчастотного давача для вимірювання густини, в’язкості, зусилля (тиску) з циліндричним резонатором було проведено серію експериментів для визначення густини та зусилля з використанням двіброчастотного методу методу Результати експериментів показали покращені метрологічні характеристики ЗВТ та дієвість методу. Результати проведених теоретичних і експериментальних досліджень впроваджено у практику таких підприємств і організацій: ТОВ «Укртехавіа» (Павлоград, Україна), «ММС Інтернешнл Белград» (Белград, Республіка Сербія); ВАТ «РПК «АДМІРАЛ»» (Дніпро, Україна), навчальний процесс Українського державного хіміко-технологічного університету, Дніпровського державного аграрно-економічного університету.Dissertation for the degree of Doctor of Sciences (Technology), Specialty 05.11.13 – «Instruments and Methods of Control and compounds` composition determination». ‒ State Higher Educational Institution «Ukrainian State Chemical Technology University» of the Ministry of Education and Science of Ukraine, Dnipro, 2019. ‒ National Technical University «Kharkiv Polytechnic Institute» of the Ministry of Education and Science of Ukraine. The dissertation is devoted to solving the scientific and applied problem of increasing the reliability of the control of technological parameters (density, viscosity, force (pressure)) in a production environment through the development of new mathematical models and methods for determining technological parameters from the amplitude-frequency characteristics of the oscillatory environment of apparatuses, the use of new multiparameter vibration frequency converters with a universal characteristic and variable signal-to-noise ratio, as well as software development STV filtering noisy measurement information with unknown distribution laws. A vibrational frequency method has been developed for monitoring and measuring the density, viscosity, force (pressure) of gas-liquid media under industrial conditions using a measuring transducer with a tubular, cylindrical resonator, mathematical models of the amplitude-frequency characteristics of technological parameters in devices of various designs are obtained. Theoretical foundations have been developed for the design of non-metallic tubular flow resonators with a wide scope. A multifunctional vibration frequency converter has been developed for measuring density, viscosity, force (pressure) with a cylindrical resonator, which has a universal characteristic. Research work on the identification of distribution laws has been completed, an Kalman filtering algorithm has been developed for measuring information with increased noise, and the structure of a multidimensional control system for technological parameters with a system for diagnosing the shape of resonator vibrations; improved device for identifying the active state of the operator. Implementation of engineering developments of the thesis was carried out at the leading enterprises of the Dnieper and abroad.
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Bouhafs, Faycal. "Semantic clustering mechanisms for communication in wireless sensor networks." Thesis, Liverpool John Moores University, 2007. http://researchonline.ljmu.ac.uk/5809/.
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