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Dissertations / Theses on the topic 'Transducer'
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Sotoudeh, A. "Transducer compensation in digital instruments : 'Intelligent' transducers." Thesis, University of Southampton, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370375.
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Dolzhenko, Egor. "Transducer dynamics." [Tampa, Fla] : University of South Florida, 2008. http://purl.fcla.edu/usf/dc/et/SFE0002380.
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Dolzhenko, Egor. "Transducer dynamics." Scholar Commons, 2007. https://scholarcommons.usf.edu/etd/217.
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Transducers are finite state automata with an output. In this thesis, we attempt to classify sequences that can be constructed by iteratively applying a transducer to a given word. We begin exploring this problem by considering sequences of words that can be produced by iterative application of a transducer to a given input word, i.e., identifying sequences of words of the form w, t(w), t²(w), . . . We call such sequences transducer recognizable. Also we introduce the notion of "recognition of a sequence in context", which captures the possibility of concatenating prefix and suffix words to each word in the sequence, so a given sequence of words becomes transducer recognizable. It turns out that all finite and periodic sequences of words of equal length are transducer recognizable. We also show how to construct a deterministic transducer with the least number of states recognizing a given sequence. To each transducer t we associate a two-dimensional language L²(t) consisting of blocks of symbols in the following way. The first row, w, of each block is in the input language of t, the second row is a word that t outputs on input w. Inductively, every subsequent row is a word outputted by the transducer when its preceding row is read as an input. We show a relationship of the entropy values of these two-dimensional languages to the entropy values of the one-dimensional languages that appear as input languages for finite state transducers.
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Marshall, Laurie D. "Transducer-baffle interaction." Thesis, Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/15821.
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Magliocchetti, Mario. "Improving the performance of MiniCan low noise hydrophone." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Jun%5FMagliocchetti.pdf.
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Ersagun, Erdem. "Multi-transducer Ultrasonic Communication." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12610403/index.pdf.
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RF and acoustic communications are widely used in terrestrial and underwater environments, respectively. This thesis examines the use of ultrasonic communication alternately in terrestrial applications. We first investigate the ultrasonic channel in order to observe whether reliable communication is possible among the ultrasonic nodes as an alternative to RF-based communications. Some key characteristics of the single-input-single-output (SISO) and single-inputmultiple-
output (SIMO) ultrasonic channel are inspected with extensive
experiments utilizing ultrasonic transmitters and receivers. Well known receiver diversity techniques are employed to combine the observations of multiple receiving ultrasonic transducers in a SIMO scheme and receiver diversity gain is
attained. The thesis also covers the implementation of a receiver node by using a low-cost microcontroller.
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Narayanan, Soundararajan Hari. "Torque transducer sensitivity study." Thesis, KTH, Maskinkonstruktion (Inst.), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-183048.
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A torque transducer or a torque sensor is a device for measuring and recording the torque on a rotating system. Torque transducers usually employ strain gauges to measure the torsional moment applied to a rotating shaft.It is to be noted that for an ideal torque transducer, it should measure only the strain that is caused by a torque. Strain due to bending load should be compensated as per the Wheatstone bridge arrangement. However, because of geometrical tolerances and assembly errors, the compensation doesn’t occur and the measured strain is a resultant of bending loads and axial loads which are undesired to measure the torque associated with the system. An analytical formulation has been developed using Matlab and this thesis gives the generalized indication of the strain due to all the associated loads. The user shall also entire the region where the strain needs to be computed and this knowledge can be useful for placing the strain gauges in the shaft accordingly. Initially, the formulation is based on a standard Torque Transducer used at Atlas Copco and then, a generalized result has been developed. The theoretical formulation is verified using the ProEngineer Mechanica software. The end user shall enter the different loads (if any) along with the geometrical tolerance values and the output will be an indication of the strain at point, strain at a region and sensitivity. The main intention of the thesis is to create a better understanding of the strain associated with the twisting, bending and axial loads and also the geometrical imperfections. The user can also make a decision on the location of strain gauges on a shaft for maximum accuracy. Finally, the differences in error from different possible configurations are compared and a conclusion has been made based on factorial design pertaining to design of experiments.Momentgivare är små sensorer som används för att mäta och registrera vridmomentet på en roterande axel. Momentgivare baseras vanligtvis på trådtöjningsmätare för att mäta vridmomentetet kring axeln de är fixerade på. Det skall noteras att en ideal momentgivare endast bör mäta den yttöjning som uppkommer på grund av ett vridmoment. Den belastning som uppkommer på grund av axelns böjning kompenseras bort med hjälp av en Wheatstonebrygga. Men på grund av geometriska toleranser och monteringsfel kan kompensationen bli felaktig och då påverkas det uppmätta momentet även av böj och axialbelastningar vilket är oönskat. En analytisk modell har utvecklats med hjälp av Matlab och denna rapport undersöker de olika lastfallens bidrag till momentfelet. Användaren kan ange området där yttöjningen skall beräknas och utifrån de beräkningarna bestämma var trådtöjningsgivarna bör placeras. Inledningsvis är beräkningarna baserade på en av Atlas Copcos momentgivare och sedan har generaliserade resultat utvecklats. De teoretiska beräkningarna verifieras med hjälp av programmet ProEngineer Mechanica. Användaren kan ange vilka belastningar som axeln känner samt de geometriska toleransvärdena och modellen beräknar då ytspänningen för den valda regionen. Det huvudsakliga syftet med denna avhandling är att skapa en bättre förståelse av ytspänningen som uppkommer på grund av vridning, böjning och axiella belastningar och även geometriska imperfektioner. Modellen kan också användas för att göra beräkningar som visar var töjningsgivare bör placeras på axeln för maximal precision. Slutligen har de introducerade felet från de olika möjliga konfigurationerna jämförts och en slutsats har dragits baserat på faktorförsök.
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Abeysekera, Jeffrey Michael. "Dual-transducer ultrasound for elastography." Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/27812.
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Medical imaging techniques provide valuable information about the internal anatomy of the body. Commonly used techniques can render many properties of the anatomy and its function, but they are limited in their ability to measure tissue mechanical properties such as elasticity. Over the past two decades there has been growing interest in developing methods of noninvasively characterizing mechanical properties of tissues; a field commonly referred to as elastography. Tissues are known to exhibit changes in mechanical properties in response to pathology. As a result, elastography has the particular potential to help physicians diagnose and locate cancerous tumors and other malignancies.
The principle of operation of elastography systems is to apply an excitation to the tissue, such as a compression, and to measure the resulting tissue
motion as it deforms. The tissue elasticity can then be inferred from the motion estimates by solving the inverse problem. Tissue motion is typically measured with ultrasound because it is fast, safe, and relatively inexpensive.
The point spread function of an ultrasound beam is anisotropic, resulting in poorer quality motion estimates in two of the three spatial directions. This thesis investigates a new method of estimating tissue motion by employing two ultrasound transducers with different view angles. The goal of using these two transducers is to create a plane of high quality 2D motion estimates. Simulations and experimental results on tissue mimicking phantoms
show that the method outperforms other commonly used 2D motion estimation methods. For example, in a tissue deformation simulation, the dual transducer method produced lower root mean square measurement error by a factor of 10 compared to a single transducer technique, and a factor of 3
compared to a single transducer with angular compounding.
A simple wire-based method of aligning the transducers into a coincident scan plane is initially developed. Later, a novel wedge-based phantom is designed for aligning the two transducers. Calibration results demonstrate improved alignment with the wedge phantom. Manual alignment is found to be repeatable with mean alignment errors under 1 degree in rotation and 1 mm in translation for all degrees of freedom after six independent trials.
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Sineiro, Guilherme da Silva. "Underwater multimode directional transducer evaluation." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2003. http://library.nps.navy.mil/uhtbin/hyperion-image/03Dec%5FSineiro.pdf.
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Thesis (M.S. in Engineering Acoustics)--Naval Postgraduate School, December 2003.Thesis advisor(s): Thomas J. Hofler, Joseph A. Rice. Includes bibliographical references (p. 53-54). Also available online.
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Santos, Djalma Simões dos. "Shear wave elastography with two-dimensional ultrasound transducer." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/3/3154/tde-01102018-142217/.
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Chronic liver diseases are the eighth leading cause of death in Brazil and a major public health problem in the world. Liver biopsy is the best available reference standard for evaluating and classifying stages of liver diseases, but it presents limitations and complications that are common in invasive methods. In recent years, elasticity imaging methods have been the focus of intense research activity with the ability to measure mechanical properties of soft tissues in a non-invasive way. Shear wave elastography is one of the most promising methods because it enables to quantitatively assess tissue elasticity. However, the current depth range of shear wave elastography impedes its application in obese patients, which have a great risk of developing liver disease. The aim of this study is to investigate the use of shear wave elastography in deeper tissues using a two-dimensional ultrasound transducer array. An efficient transducer array arrangement was simulated, fabricated and characterized. The results show that the proposed transducer configuration presents enhanced transmitting capabilities for generating tissue displacement in deeper tissues. In addition, numerical simulations were performed in order to track the tissue deformation and reconstruct its elastic properties.Doenças crônicas do fígado são a oitava causa de morte no Brasil e um dos principais problemas de saúde pública do mundo. A biópsia do fígado é o melhor padrão de referência disponível para avaliação e classificação dos estágios das doenças hepáticas, mas apresenta limitações e complicações que são comuns nos métodos invasivos. Nos últimos anos, métodos de imagem por elasticidade têm sido o foco de intensa atividade de pesquisa, pois têm a capacidade de medir propriedades mecânicas dos tecidos moles de maneira não invasiva. A elastografia por ondas de cisalhamento é um dos métodos mais promissores, pois permite avaliar quantitativamente a elasticidade do tecido. No entanto, a atual faixa de profundidade da elastografia por ondas de cisalhamento impede sua aplicação em pacientes obesos, que apresentam grande risco de desenvolver doença hepática. O objetivo deste estudo é investigar o uso da elastografia por onda de cisalhamento em tecidos mais profundos usando um transdutor de ultrassom bidimensional. Uma configuração eficiente de transdutores matriciais foi simulada, fabricada e caracterizada. Os resultados mostram que o transdutor proposto possui capacidade de transmissão melhorada para gerar deslocamento em tecidos profundos. Além disso, simulações numéricas foram realizadas para monitorar a deformação do tecido e reconstruir suas propriedades elásticas.
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Gunzel, Charles A. "FSR based force torque transducer design." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1993. http://handle.dtic.mil/100.2/ADA271337.
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Cai, Ming. "A PolyMUMPs Capacitive Micromachined Ultrasonic Transducer." Thesis, University of British Columbia, 2011. http://hdl.handle.net/2429/34000.
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This work presents the design of Capacitive Micromachined Ultrasonic Transducers (CMUTs) with one and multiple bottom electrodes and their fabrication using the PolyMUMPs technique provided by MEMSCAP Inc. It also reports a new behavioral model of the CMUTs written in VHDL-AMS, complemented by a comparison between finite element analysis, behavioral simulations and experimental measurements on the newly fabricated CMUT arrays. As an improvement on a previously developed VHDL-AMS CMUT behavioral model [1], where the CMUT was treated as a movable rigid plate capacitor, a mode decomposition approach was used in the present work to better approximate the dynamics of the CMUT membrane. Besides the frequency responses, time responses and electro-mechanical conversion efficiency, the simulation results also showed the electrostatic spring softening effect, and the optimization of the DC/AC voltage ratio that leads to a maximum transmitted acoustic power. The CMUT membrane capacitance variation predicted by the model compares favorably with results from the finite element analysis, with better matching than the previously developed models. Polytec Micro System Analyzer (Polytec MSA-500) using Laser Doppler Vibrometry was used for the experimental characterization, in which the pull-in voltage, vibration modes and their respective resonant frequencies were determined. Characterization results were compared with the ones from the finite element analysis and the behavioral model simulations, and excellent agreement was shown.
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Iqbal, Tahir. "Nanoplasmonic grating coupler for transducer applications." Thesis, Queen's University Belfast, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.602547.
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This thesis investigates the excitation of surface plasmon polaritons (SPPs) on a one dimensional (ID) grating etched in a gold film on a (high-index) gallium phosphide (GaP) substrate. The experimental component of the work addresses the design and building of an optical set-up for the far-field characterization of the spatially confined (-20 x 20μm) gratings in transmission, with better than 2° angular resolution, and the commissioning and use of a WiTec scanning near-field optical microscope (with bespoke modification) for near-field analysis. The purpose of the latter is to track the propagation of SPPs on the planar gold film region beyond the grating launch site. Both the far- and near-field experimental data are interpreted with reference to modelled results generated by using COMSOL, a commercial, finite-element analysis software package. Coupling efficiency of the incident light to the SPP is studied as a function of slit width where the grating periodicity and the (optimized) gold thickness remain constant. Defining a simple and convenient measure of the coupling efficiency the optimum slit width is found to be between 1/3 and 1/2 of the grating period. Such grating devices support only the fundamental mode and offer less radiative scattering of SPPs. The experimental results are in agreement with the far-field modelling results and the optimum slit-width range in the grating devices is close to that suggested by near-field analysis. The (maximum) propagation length, Lspp, just outside the grating device is found to be -13.33 ± 0.13μm under excitation by laser light of 785 nm wavelength. The Lspp is associated with the full width at half maximum (FWHM) of the SPP resonance. The grating on high refractive index substrate described above has intended application in heat assisted magnetic recording where it is envisaged that the focussing of optical energy to nanoscale dimensions will take place using SPPs generated by using a grating coupler integrated on a semiconductor laser chip. In addition, an optimal 1 D grating was designed and fabricated on a 50 nm Au film on a (low-index) glass substrate for application as a highly sensitive biosensor. The sensitivity was found to be 524 nm per refractive index unit (RIU) which is highly competitive with many other plasmon-based biosensors while being of simpler geometrical structure and more economical design.
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Robertson, Toby James Gray. "Advances in ultrasonic capacitive transducer technology." Thesis, University of Warwick, 2001. http://wrap.warwick.ac.uk/66936/.
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This thesis describes the development and characterisation of a variety of novel capacitive ultrasonic transducers for use in air-coupled and immersion applications. The first sections of this thesis examine the fabrication and initial characterisation of novel fully micromachined transducers. These devices, produced using a silicon surface micromachining process, consisted of a large laterally dimensioned (up to 5mm square), silicon nitride membrane, typically O.S-2I1m in thickness, above a nominal 211m air gap. Typical operation in air was observed in the MHz region. The effects of membrane thickness and size were studied, as well as the effect of applied bias voltage. Differences between batches of devices were investigated. Their dynamic membrane displacements were measured using interferometric techniques. When driven with transient voltages typical displacements of a few nm were observed. Their radiated fields were also investigated, and compared to plane piston approximations, calculated with a Matlab™ program. Good agreement was found. This thesis also describes the development and characterisation of three novel aircoupled focusing transducers. Two of these devices utilised shaped backplates, one being cylindrically concave, and the other conically concave, to produce lines of focus. The third device utilised an off-axis parabolic mirror to produce a point of focus. The development and characterisation of each is described. Their frequency responses were measured, and found to be comparable with similar planar transducers. Experiments were devised to measure their vertical and lateral resolutions, the latter typically being found to be approximately a wavelength of their centre operating frequency (-500kHz). Their radiated peak sound pressure fields were measured, and for the cylindrical and conical device compared to theoretical plane piston approximations calculated with a Matlab™ program, with good agreement of form being found. Finally, all three transducers were used to create 3-D images of a two pence coin, using amplitude and time of arrival data. Reasonable images resulted. The final section. examines the development of an immersion transducer. This was characterised as both source and receiver, showing increases in both bandwidth and frequency response than when used in air. The effects of backplate surface properties on the characteristics of the device were studied. using a range of roughened, polished, and photolithographic metallic backplates. In addition, the effect of applied bias was also investigated. Sound pressure fields were measured, using both broadband and narrowband tone burst excitations. and compared to theoretical predictions from plane piston theory. These were calculated using a Matlab™ program, with good agreement found. The transducer was then used to produce pulse-echo C-scan images of artificially induced machined defects in Perspex and aluminium plates. Excellent images resulted.
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Medley, Andrew. "A new type of acoustic transducer." Thesis, University of Warwick, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.426048.
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Steel, Geoffrey Alan. "Techniques for tailoring sonar transducer responses." Thesis, University of Birmingham, 1987. http://etheses.bham.ac.uk//id/eprint/1375/.
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This work is concerned with the design of sonar transducers operating in the frequency range 100 kHz to 1 MHz. The transducer frequency responses are predicted using a one-dimensional transmission line analysis. Differences between predicted and measured results are shown to be caused by intermodal coupling between planar and thickness modes of vibration. Conventional transducer designs achieve wide bandwidth using quarter-wave matching layers. In this work the piezoelectric-tunable transducer is investigated as a possible alternative. This structure consists of a pair of ceramics, one of which is driven by a voltage source and the other has a passive electrical load. It is shown that the resonant frequency is variable over more than one octave but the instantaneous bandwidth is only around 10% of the centre frequency. The same transducer can be controlled actively by applying voltages to both ceramics. In this case transducer characteristics are determined by the relative amplitude and phase of the two voltage sources, which can be chosen to give the same results as with passive control. Data is often required for the velocity and attenuation of sound in the materials being used. For this purpose several measuring techniques are described, all of which use a solid buffer rod in place of the more common water tank measurements.
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Ma, Jinge. "Design of Frequency Output Pressure Transducer." Thesis, University of North Texas, 2015. https://digital.library.unt.edu/ark:/67531/metadc804933/.
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Piezoelectricity crystal is used in different area in industry, such as downhole oil, gas industry, and ballistics. The piezoelectricity crystals are able to create electric fields due to mechanical deformation called the direct piezoelectric effect, or create mechanical deformation due to the effect of electric field called the indirect piezoelectric effect. In this thesis, piezoelectricity effect is the core part. There are 4 parts in the frequency output pressure transducer: two crystal oscillators, phase-locked loop (PLL), mixer, frequency counter. Crystal oscillator is used to activate the piezoelectricity crystal which is made from quartz. The resonance frequency of the piezoelectricity crystal will be increased with the higher pressure applied. The signal of the resonance frequency will be transmitted to the PLL. The function of the PLL is detect the frequency change in the input signal and makes the output of the PLL has the same frequency and same phase with the input signal. The output of the PLL will be transmitted to a Mixer. The mixer has two inputs and one output. One input signal is from the pressure crystal oscillator and another one is from the reference crystal oscillator. The frequency difference of the two signal will transmitted to the frequency counter from the output of the mixer. Thus, the frequency output pressure transducer with a frequency counter is a portable device which is able to measure the pressure without oscilloscope or computer.
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O'Donnell, Ryan M. "Development of a Molecular Optoelectronic Transducer." Ohio University Honors Tutorial College / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ouhonors1275678264.
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Li, Juan. "Na, K-ATPase as a signaling transducer /." Stockholm : Karolinska institutet, 2007. http://diss.kib.ki.se/2007/978-91-7357-453-2/.
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Sandhu, Randeep. "The transducer-like proteins of Campylobacter jejuni." Thesis, University of Leicester, 2011. http://hdl.handle.net/2381/9910.
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Campylobacter jejuni is the leading cause of gastrointestinal disease in the developed world. Chemotactic motility is a pre-requisite for intestinal colonisation by C. jejuni. In silico analysis of the C. jejuni NCTC 11168 genome identified homologues of 10 chemotaxis receptor and two aerotaxis genes. Six of the ten putative Transducer-like proteins (Tlp 1, 2, 3, 4, 7 and 10) resemble chemoreceptors of Escherichia coli. The aim of this project is to characterise the C. jejuni Tlp1-4 chemoreceptors. The genes encoding the Tlps were inactivated using an insertional inactivation strategy. Isogenic mutants were made in tlp1, tlp2 and tlp4; a final mutant in tlp3 could not be obtained. A tlp1 complement was also constructed in this work. The tlp1 mutant showed reduced chicken colonisation ability when tested by our collaborators. Chemotactic phenotypes of the tlp mutants were determined in the swarm assay; the tlp mutants appeared defective for chemotaxis when compared with the wild-type and non-motile flaAB mutant. The Capillary assay and Hard-Agar Plug (HAP) assay were developed as methods to ascertain the ligand specificities of the Tlp chemoreceptors under study. Unfortunately, the Capillary assay proved to be insufficiently reproducible for effective use with C. jejuni. The HAP procedure was optimised using a C. jejuni wild-type motile variant. Positive chemoattractant responses were observed in NCTC 11168 for the first time towards a range of chemicals. Data derived from the modified HAP assay indicated that Tlp1 may be the receptor for serine. Chemotactic responses could not be detected in the tlp2 and tlp4 mutants in the HAP assay. The signalling domain of Tlp1 was purified using a polyhistidine tag and used to produce a polyclonal antibody. The Tlp1 primary antibody and immunofluorescence labeling has shown for the first time that the Tlps cluster at the cell poles in C. jejuni.
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Haddad, George. "AUTOMATIC PARTICLE COUNTING USING AN ACOUSTIC TRANSDUCER." Master's thesis, University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2646.
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Aerosol particle detection and determination finds important applications in the commercial, military and aerospace sectors. Monitoring of clean room environments, and spacecraft integration and check out facilities are some of the most important aplications. In the early days test filters were examined with a microscope to determine the number and size of particles that were being removed from air. Today, most of the commercially available clean room airborne particle counters work on a light scattering principle. They are referred to as Optical Particle Counter or OPC. Essentially, they utilize a very bright laser light source to illuminate the particles. The burst of light energy is converted into a pulse of electrical energy. By measuring the height of the signal and counting the number of pulses the sizes and quantities of particles could thus be determined. The microscope and the OPC techniques have their limitations. The microscope technique is a post contamination assessment technique and the OPC is costly, hard to maintain, lack in counting efficiency and is not mobile. This experimental study demonstrates a novel and inexpensive particle detection technique which is based on the acoustic signature of airborne particles as they are accelerated through an acoustic transducer. The transducer consists of an inlet converging nozzle, a capillary tube and an expansion section. If the air is laden with particles, as the flow accelerates through the inlet, the particles cannot follow the large change in velocity due to their inertia. Vortices are generated as air flows over the particles prior to entering the capillary. These vortices are believed to generate sound, which is amplified by the transducer acting as an organ pipe. This sound emission if measured contains frequencies that are harmonics of the natural frequency of the transducer's air column. Results show how the frequency content of the acoustic signature relates to the fundamental frequency of the transducer's air column. The transducer is able to detect micron sized particles ( 5 to 50 micron) and the sound intensity is a function of the flowrate but not of particle size. This study also shows the ability of the transducer to determine particle concentration as low as few parts per liter (ppl) and compare the data with that obtained from a commercially available aerodynamic particle sizer.M.S.M.E.
Department of Mechanical, Materials and Aerospace Engineering;
Engineering and Computer Science
Mechanical Engineering
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Tanner, K. E. "The design of a fracture movement transducer." Thesis, University of Oxford, 1985. http://ora.ox.ac.uk/objects/uuid:5c02bdde-ecef-4305-89dc-b4788265865f.
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The literature on bone growth, fracture healing, fracture treatment and the effects of forces and movements on these is reviewed. Some methods of assessing the progress of fracture union are considered. The conclusion from this is that a fracture movement transducer is needed for use on an external fracture fixator, and the design criteria are outlined. The possible types of transducers are considered and a system of light falling on lateral effect photodetectors was used. The linearizing algorithms applicable to the employed detectors are discussed and tested. The electronic circuits were designed and revised, initially to produce a reasonable power consumption, and then to give a system with reduced noise levels and improved linearity. Isolation amplifiers were required to prevent leakage currents reaching the patient from the mains powered computer. The algorithms relating the movements of the transducer to the movements at the fracture site were derived, including the use of elasticity theory to calculate the bending of the fixator pins. The engineering descriptions of the patient tests and the methods of calculating the fracture stiffness are considered. The transducer was calibrated, and consideration was given to the effect of the fixator pins loosening in the bone. Seven patients, all with tibial fractures, six injured in road traffic accidents and one footballing injury, were tested and their clinical histories were reviewed. Comparison was made between the results from the displacement transducer and a strain gauge transducer, related to the clinical history. It is concluded that this transducer, although useful, has more relevance as a research than as a clinical tool, but that further tests would lead to increased further understanding of fracture healing.
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Blakely, Patrick A. "Wireless Transducer Systems Architectures – A User’s Perspective." International Foundation for Telemetering, 2003. http://hdl.handle.net/10150/607468.
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International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, NevadaThis paper provides essential requirements and describes some possible architectures of so-called Wireless Transducers Systems from the user’s perspective and discusses the application advantages of each architecture, in the airplane-testing environment. The intent of this paper is to stimulate discussion in the transducer user and supplier communities and standards committees, leading to increased product suitability and lower cost for commercial off the shelf wireless transducer products.
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Hughes, David. "Monotone local linear estimation of transducer functions." Thesis, University of Liverpool, 2014. http://livrepository.liverpool.ac.uk/2007866/.
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Local polynomial regression has received a great deal of attention in the past. It is a highly adaptable regression method when the true response model is not known. However, estimates obtained in this way are not guaranteed to be monotone. In some situations the response is known to depend monotonically upon some variables. Various methods have been suggested for constraining nonparametric local polynomial regression to be monotone. The earliest of these is known as the Pool Adjacent Violators algorithm (PAVA) and was first suggested by Brunk (1958). Kappenman (1987) suggested that a non-parametric estimate could be made monotone by simply increasing the bandwidth used until the estimate was monotone. Dette et al. (2006) have suggested a monotonicity constraint which they call the DNP method. Their method involves calculating a density estimate of the unconstrained regression estimate, and using this to calculate an estimate of the inverse of the regression function. Fan, Heckman and Wand (1995) generalized local polynomial regression to quasi-likelihood based settings. Obviously such estimates are not guaranteed to be monotone, whilst in many practical situations monotonicity of response is required. In this thesis I discuss how the above mentioned monotonicity constraint methods can be adapted to the quasi-likelihood setting. I am particularly interested in the estimation of monotone psychometric functions and, more generally, biological transducer functions, for which the response is often known to follow a distribution which belongs to the exponential family. I consider some of the key theoretical properties of the monotonised local linear estimators in the quasi-likelihood setting. I establish asymptotic expressions for the bias and variance for my adaptation of the DNP method (called the LDNP method) and show that this estimate is asymptotically normally distributed and first{-}order equivalent to competing methods. I demonstrate that this adaptation overcomes some of the problems with using the DNP method in likelihood based settings. I also investigate the choice of second bandwidth for use in the density estimation step. I compare the LDNP method, the PAVA method and the bandwidth method by means of a simulation study. I investigate a variety of response models, including binary, Poisson and exponential. In each study I calculate monotone estimates of the response curve using each method and compare their bias, variance, MSE and MISE. I also apply these methods to analysis of data from various hearing and vision studies. I show some of the deficiencies of using local polynomial estimates, as opposed to local likelihood estimates.
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Berggren, Christine. "Affinity biosensors based on a capacitive transducer." Lund : Lund University, 1998. http://catalog.hathitrust.org/api/volumes/oclc/68945028.html.
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FREITAS, NETO Leopoldo Mayer de. "Utilização do ultrassom para diagnosticar a prenhez e o sexo de fetos de pequenos ruminantes gerados a partir de monta natural e da transferência de embriões frescos, congelados e vitrificados." Universidade Federal Rural de Pernambuco, 2010. http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/5706.
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Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq
In this work, divided into three experiments, the aim was to verify the possibility to diagnose the pregnancy of does and ewes by different pathway access and diagnose the fetuses sex originated by natural mating and transfer of fresh and cryopreserved embryos. The examinations were carried out using an ultrasound scanner equipped with a linear transducer (6.0 and 8.0 MHz) used by transrectal and transabdominal via and a microconvex endocavitary (5.0 and 7.5 MHz) transducer used by transvaginal via. In the first experiment was verified the viability of the ultrasound examination by transretal, transabdominal and transvaginal via to diagnose pregnancy in goats (n = 240) and ewes (n = 320) at days 30th, 45th, 60th and 75th. In does and ewes the ultrasound examination was faster (P < 0.05) on days 30th and 45th of pregnancy, however by transabdominal via was faster on day 60th and 75th. In both species the time of pregnancy diagnose was greater (P < 0.05) on day 30th than the others days while this time was smallest (P < 0.05) at day 75th than day 45th and 60th. Independent of the examination via and the day of pregnancy the average time to diagnose the pregnancy was shorter (P < 0.05) in does than in ewes. Independing of the specie and the day of pregnancy the average time to diagnose the pregnancy by transrectal via was shorter (P < 0.05) than the other vias and the transvaginal via was shorter (P < 0.05) than the transabdominal one. In the second experiment, in order to improve the sexing of Boer fetuses (n = 123) by transrectal ultrasonography, the aim was to identify the migration period of the genital tubercle and its later differentiation into genital structures in fetuses derived from natural mating (TI) and fetus from fresh (TII), frozen (TIII) and vitrified (TIV) embryo transfer collected 7 days after breeding. Migration of the genital tubercle occurred earlier (P < 0.05) in TI (45.21 ± 3.31 days) than in TII (48.50 ± 3.70 days), TIII (48.93 ± 3.61 days) and TIV (48.85 ± 3.23 days). The visualization of the scrotum, prepuce and vulva occurred earlier (P < 0.05) in TI (51.20 ± 2.56; 50.35 ± 1.59; 49.75 ± 1.73 days) than in TII (53.25 ± 2.02; 53.37 ± 1.92; 51.76 ± 2.10 days),TIII (53.37 ± 1.92; 52.31 ± 2.00; 51 ± 78 ± 2.22 days) and TIV (54.06±1.75; 52.46 ± 1.95; 51.91 ± 2.06 days). In the third experiment, in order to improve fetal sexing by ultrasonography in Dorper ewe breed (n = 130), the objective was to identifythe migration period of the genital tubercle and the period of the visualization of external genital structures in fetuses derived from natural mating (TI) and from fresh (TII), frozen (TIII) and vitrified (TIV) embryos transfer collected 7 days after breeding. Migration of the genital tubercle occurred earlier (P < 0.05) in TI (42.21±2.86 days) than in TII (43.98±3.00 days), TIII (44.97±1.83 days) and TIV (44.58±1.97days). The visualization of scrotal bag, prepuce and vulva occurred, respectively, earlier (P < 0.05) in TI (45.22±1.25; 45.95±1.53; 45.01±.103 days) than in TII (48.91±1.92; 48.52±1.41; 47.41±1.41 days), TIII (49.97±1.08; 49.18±2.00; 47.64±1.82 days) and TIV(50.12±1.66; 49.27±1.1.61; 47.93±1.92 days). The results allow to conclude that the pregnancy diagnose may be performed by transrectal, transabdominal and transvaginal via, as well as, that is faster by transrectal via and hat the time for diagnosing is shorterin advanced pregnancy and in goat specie. Is also possible to conclude, taking into consideration the final position of the genital tubercle, that goat fetal sexing can be done from the 55th day onward in fetuses produced by natural mating and from the 60th day onward in fetuses derived from cryopreserved embryos. It can also be concluded that, real-time ultrasonography is a reliable tool for fetal sex determination in sheep after Day 50 of pregnancy taking into account both the location of the genital tubercle and the identification of external genital structures. In ovine species the fetal sexing can be done from the 50th day onward in fetuses produced by natural mating and from the 55th day onward in fetuses derived from cryopreserved embryos. Finally is possible to conclude that real-time ultrasonography is a reliable tool for early pregnancy diagnose in small ruminant as well as that to identify the sex on the first 60 days of pregnancy.
Com este trabalho, dividido em três experimentos, objetivou-se verificar a possibilidade de realizar o diagnóstico de prenhez em cabras e ovelhas por diferentes vias de acesso e sexar fetos originados de monta natural e da transferência de embriões frescos e criopreservados. Os exames foram realizados com um aparelho de ultrassom equipado com um transdutor linear (6,0 e 8,0 MHz) utilizado pelas vias transretal e transabdominal e outro microconvexo (5,0 e 7,5 MHz) endocavitário utilizado por via transvaginal. No primeiro experimento verificou-se a viabilidade do exame ultrassonográfico pelas vias transretal, transabdominal e transvaginal para diagnosticar a gestação de cabras (n = 240) e ovelhas (n = 320) no 30o, 45o, 60o e 75o dia. Nas cabras e ovelhas, o exame ultrassonográfico pela via transretal foi mais rápido (P < 0, 05) no 30o e no 45o dia da gestação, mas, pela via transabdominal foi mais rápido no 60o e no 75o dia. Em ambas as espécies, a duração do diagnóstico de gestação foi maior (P < 0,05) no 30o dia do que nos demais, enquanto que a duração do diagnóstico no 75o dia foi menor (P < 0,05) do que no 45o e 60o. Independentemente da via de exame e do dia da gestação, o tempo médio para diagnosticar a gestação foi menor (P < 0,05) nas cabras do que nas ovelhas. Independentemente da espécie e do dia da gestação, o tempo médio para diagnosticar a gestação pela via transretal foi menor (P < 0,05) do que as demais e o da transvaginal foi menor (P < 0,05) do que o da via transabdominal. No segundo experimento, com a finalidade de aperfeiçoar a sexagem de fetos (n = 123) caprinos da raça Boer por via transretal, procurou-se identificar o período de migração do tubérculo genital e sua diferenciação nas estruturas da genitália de fetos derivados de monta natural (TI) e da transferência de embriões frescos (TII), congelados (TIII) e vitrificados (TIV) colhidos 7 dias após a cobertura. A migração do tubérculo genital ocorreu mais cedo (P < 0,05) no TI (42,21±2,86 dias) do que no TII (43,98±3,00 dias), TIII (44,97±1,83 dias) e no TIV (44,58±1,97 dias). A visibilização da bolsa escrotal, prepúcio e vulva ocorreu precocemente (P < 0,05) no TI (45,22±1,25; 45,95±1,53;45,01±1,03 dias) do que no TII (53,25 ± 2,02; 53,37 ± 1,92; 51,76 ± 2,10 dias), TIII (53,25 ± 2,02; 53,37 ± 1,92; 51.76 ± 2,10 dias) e TIV (54,06±1,75; 52,46 ± 1,95;51,91 ± 2,06 dias). No terceiro experimento, com o propósito de aperfeiçoar a sexagem de fetos (n = 130) ovinos da raça Dorper por via transretal, procurou-se identificar o período de migração do tubérculo genital e sua diferenciação nas estruturas da genitália de fetos derivados de monta natural (TI) e da transferência de embriões frescos (TII), congelados (TIII) e vitrificados (TIV) colhidos 7 dias após a cobertura. A migração do tubérculo genital ocorreu mais cedo (P < 0,05) no TI (45,21 ± 3,31 dias) do que no TII (48,50 ± 3,70 dias), TIII (48.50 ± 3.70 dias) e no TIV (48,85 ± 3,23 dias). A visibilização da bolsa escrotal, prepúcio e vulva ocorreu precocemente (P < 0,05) no TI (51,20 ± 2,56; 50,35 ± 1,59; 49,75 ± 1,73 dias) do que no TII (53,25 ± 2,02; 53,37 ± 1,92; 51,76 ± 2,10 dias), TIII (53,25 ± 2,02; 53,37 ± 1,92; 51.76 ± 2,10 dias) e TIV (54,06±1,75; 52,46 ± 1,95; 51,91 ± 2,06 dias). Os resultados permitem concluir que o diagnóstico de gestação pode ser realizado pelas vias transretal, transabdominal etransvaginal, bem como que é mais rápido pela via transretal, na gestação avançada e na espécie caprina. É também permissível concluir que, com base no posicionamento final do tubérculo genital, é recomendável sexar fetos caprinos provenientes de monta natural somente a partir do 55o dia de prenhez e a partir do 60o dia naqueles derivados da transferência de embriões frescos e criopreservados. Nos ovinos a sexagem fetal já pode ser efetuada a partir do 50o dia de prenhez nos fetos oriundos de monta natural e a partir do 55o dia naqueles originados da transferência de embriões frescos e criopreservados. Ainda é possível concluir que a ultrassonografia em tempo real é uma ferramenta importante para diagnosticar precocemente a prenhez nos pequenos ruminantes, assim como identificar o sexo fetal nos primeiros 60 dias de gestação
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Bäckström, Thomas. "Integrated enerty transducer drive for hybrid electric vehicles." Doctoral thesis, KTH, Electric Power Systems, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-2990.
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Motieian, Najar Mohammad Hadi. "Design and analysis of capacitive micromachined ultrasound transducer." Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/28690.
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Capacitive Micromachined Ultrasound Transducers (CMUTs) have been recently introduced as a viable substitute to piezoelectric transducers in medical ultrasound imaging. CMUT possesses advantages such as allowing high frequency, having wide bandwidth, high sensitivity, low cost, CMOS compatibility and being easy to fabricate.
This thesis is motivated by movement towards a better detection of breast tumors using ultrasound imaging techniques, which CMUTs have promised to achieve. Therefore, CMUTs were designed to fulfill requirements of this application in terms of resonant frequency, pull-in voltage and geometrical dimensions. The entire design and analysis were performed considering that the CMUTs are to be fabricated using PolyMUMPs technology, for this technology being precise, accurate and well established in the micro-electromechanical systems (MEMS) community.
CMUTs were first analytically modeled and designed by exploiting the parallel-plate capacitor equations. A behavioral model was developed in VHDL-AMS, which, unlike previous models, incorporates the non-linear electromechanical relations of the CMUT. The behavioral model has the advantage of being more time efficient than finite element models (FEM) and more accurate than analytical models.
Prior to fabrication, a 3D FEM was developed in COMSOL Multiphysics® software. Resonant frequency analysis determined the frequency response and eigenfrequencies of the CMUT, which could not be determined using previous models. Parametric analysis determined the pull-in voltage, the spring constant and spring softening effect, the variation in capacitance and the electromechanical efficiency of the CMUT. The CMUT resonated at 5.868MHz frequency and the collapse voltage was determined at 275V using FEM results, which were close to analytical modeling results and in excellent agreement with behavioral modeling results. The thickness and the radius of the circular CMUT membrane were found to be 1.5μm and 32μm, respectively. The air/vacuum gap distance was 0.75μm and the insulation layer was 0.6μm.
The CMUTs were fabricated in cell and array form. An array of 128 elements each containing 118 cells were fabricated to be compatible with existing ultrasound probes. Unfortunately, due to mal-fabrication by the company, which was experimentally proved, the experimental results were not as successful.
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Berger, Pascal B. "Development of an optical probe for transducer calibration." Thesis, Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/19437.
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Wang, Qi 1971. "A biomechanically optimized tactile transducer and tactile synthesis /." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=111874.
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This thesis falls into the field of tactile displays that are meant to produce realistic tactile sensations, which replicate tactile sensations arising naturally when humans interact with the real world.To begin with we need to know the biomechanics of the glabrous skin in human subjects. To this end, small patches of fingerpad skin are tested in vivo for their biomechanical properties under tangential loading. The skin is quasi-statically stretched and sheared to obtain its effective Young's modulus. Moreover, isotonic and isometric testing conditions are implemented to identify the viscoelasticity model of the skin. The results show a great deal of variability across subjects and it is observed that the glabrous skin exhibits nonlinear stiffening in tangential traction. The skin is consistently more elastic across the ridges, compared to along the ridges, regardless of the location of the sample on the fingerpad. The skin behaves visco-elastically but relaxes about twice as fast as it creeps. Finally, it is found that under large deformation, there is consistently 80% of hysteretic loss for a wide range of loading conditions.
Based on the results obtained by controlled testing, a high performance distributed display is designed. The display has a compact, yet modular structure. Its 6x10 piezo bimorph actuator array has a spatial resolution of 1.8x1.2 millimeters and a wide temporal bandwidth. The actuator mounting method is improved from conventional cantilever to dual-pinned lever, giving the actuator the capability of optimally coupling with glabrous skin. By using previously measured biomechanical data of the skin, we tune the parameters of the actuators to be optimal in terms of real deflection when they couple with the skin. The blocked force of the individual actuators can be adjusted from 0.15 N to 0.22 N to accommodate different applications. It is self-contained in a 150 cm3 volume and may be interfaced to most computers, provided that two analog outputs and six digital IO lines are available. Both public demonstration and psychophysical experiments have validated its effectiveness in rendering virtual tactile features.
The availability of a display raises the question of what signals should be used to drive it in order to render specific sensations. Some progress is made in this direction by analyzing the contact mechanics of fundamental cases, such as isolated indentation and traveling undulation. With the intention of explaining a tactile illusion engendered by straining the fingertip skin tangentially in a progressive wave pattern, resulting in the perception of a moving undulating surface, we carry out a contact mechanics analysis to derive the strain tensor field induced by a sinusoidal surface sliding on a finger, as well as the field created by a tactile transducer array deforming the fingerpad skin by lateral traction. We find that the first field can be well approximated by the second. Our results imply that, first, tactile displays using lateral skin deformation can generate tactile sensations similar to those using normal skin deformation. Second, there is a synthesis approach to achieve this result given constraints on the design of tactile stimulators. Third, the mechanoreceptors embedded in the skin must respond to the deviatoric part of the strain tensor field and not to its volumetric part. Finally, many tactile stimuli might represent for the brain an inverse problem to be solved.
Using the results of these investigations, we have demonstrated the feasibility of producing high-fidelity virtual tactile sensations.
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Crump, Stephen John. "Design of a high performance digital current transducer." Thesis, Coventry University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360238.
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Rashedin, Razib. "Novel miniature matrix array transducer system for loudspeakers." Thesis, Cardiff University, 2007. http://orca.cf.ac.uk/56177/.
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Conventional pistonic loudspeakers, by employing whole-body vibration of the diaphragm, can reproduce good quality sound at the low end of the audio spectrum. Flat panel speakers, on the other hand, are better at high frequency operation as the reproduced sound at high frequency from a flat panel speaker is not omni-directional as in the case of a conventional loudspeaker. Although flat-panel speakers are compact, small and have a better high frequency response the poor reproduction of bass sound limits its performance severely. In addition, the flat panel speakers have a poor impulse response. The reason for such poor bass and impulse response is that, unlike the whole body movement of a conventional loudspeaker diaphragm, different parts of the panel in a flat panel loudspeaker vibrates independently. A novel loudspeaker has been successfully designed, developed and operated using miniature electromagnetic transducers in a matrix array configuration. In this device, the whole body vibration of the panel reduces the poor bass and impulse response associated with present flat panel speakers. The multi-actuator approach combines the advantages of conventional whole body motion with that of modern flat panel speakers. An innovative miniature electromagnetic transducer for the proposed loudspeaker has been designed, modelled and built for analysis. Frequency Responses show that this novel transducer is suitable for loudspeaker application because of its steady and consistent output over the whole audible frequency range and for various excitation currents. Measurements on various device configurations of this novel miniature electromagnetic transducer show that a moving coil transducer configuration having a magnetic diaphragm is best suited for loudspeaker applications. Finite element modeling has been used to examine single transducer operation and the magnetic interaction between neighbouring transducers in a matrix array format. Experimental results show the correct positioning of the transducers in a matrix configuration reduces the effects of interferences on the magnetic transducers. In addition, experimental results from the pressure response measurement show an improvement in bass response for the longer array speaker.
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McIntosh, James Stuart. "Advances in capacitive micromachined ultrasonic transducer (CMUT) technologies." Thesis, University of Warwick, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.396401.
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Bäckström, Thomas. "Integrated energy transducer drive for hybrid electric vehicles." Doctoral thesis, KTH, Elkraftteknik, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-2990.
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Smith, Tarren MJ. "Driving techniques for high power PZT transducer arrays." Thesis, Cape Peninsula University of Technology, 2006. http://hdl.handle.net/20.500.11838/1089.
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Thesis Presented for the Degree of
Magister Technologiae
in the Department of Electrical Engineering
Cape Peninsula University of Technology
2006Because of the nature of piezoelectric ceramics and the physical construction pf high power piezoelectric transducers, such devices are inherently non-linear and become unpredictable when driven at high power. To drive an ultrasonic transducer or an array thereof efficiently, specific resonant points are used. These poin~s are characterised by the devices' mechanical modes of oscillation. At high electrical power levels, the resonance points of PZT transducers vary. The movement of the resonances points in the frequency domain, coupled with the transducers high Q, is severe enough to seriously hamper the devices' efficiency. The problem is specifically apparent when multiple transducer arrays are driven at power. The electrical fluctuations and interactions of the characteristics of separate transducers cause arrays to be driven efficiently at a single resonance point. To efficiently drive an array of PZT transducers it is necessary to employ a .suitable technique. Although several methods exist in the literature, each is designed for a specific configuration of transducers and dedicated matching circuitry. The fundamental flaw in most methods is that they are conceived with the assumption all PZT transducers are identical and can be driven as such. Inherent nonlinearities caused by poling and construction methods, result in each transducer to be slightly different causing a superposition of resonance frequencies for each transducer array. Existing methods cannot be used to efficiently drive generic transducer arrays and a novel approach has been adopted to accommodate transducer nonlinearities. This novel approach can be described as a culmination of two driving techniques and has been named, Swept Frequency Dwelling (SFD). This thesis examines five different driving techniques and quantifies their effectiveness by means of experimental evaluation proficiencies. The driving techniques are grouped into two categories - straight driving techniques and frequency sweeping techniques - which are compared and evaluated. In conclusion, a novel method for driving ultrasonic transducer arrays was established with the aim of eliminating some detrimental effects of other driving techniques, while exploiting some of their positive attributes and was found to be effective.
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Abrar, Aneela. "Ultrasonic transducer design and optimisation with mathematical modelling." Thesis, University of the West of Scotland, 2004. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.751385.
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Vaish, Nitika. "Optomechanical transducer based on a single quantum dot." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAY074.
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Dans le contexte de la nanomécanique, les systèmes hybrides quantiques sont des oscillateurs mécaniques couplés à un seul objet quantique individuel. Ces systèmes offrent des possibilités radicalement nouvelles pour la fabrication de transducteurs optomécaniques extrêmement sensibles et ultra-compacts, qui peuvent servir de capteurs de position ou de nano-moteurs.L’objet étudié dans ce travail est un système hybride constitué d’une boite quantique semi-conducteur unique couplée aux vibrations d’un fil photonique. Il a été démontré dans l'équipe, il y a quelques années, que l'énergie de transition de la boite quantique dépend de la contrainte générée par les oscillations du fil.Dans cette thèse, nous démontrons l'effet inverse, où chaque photon émis par la boite quantique s'accompagne d'une force qui entraîne l’oscillations du fil photonique. Ceci permet de réaliser un nano moteur fonctionnant grâce à la contrainte générée par une seule boite quantique pilotée par laser. L'effet est appelé "effet marteau quantique". Ce résultat ouvre la possibilité de la réalisation future d’un état quantique du mouvement par le transfert de la « quanticité » d'un système à deux niveaux vers le mouvement d’un oscillateur mécanique macroscopiqueIn the context of nanomechanics, quantum hybrid systems are mechanical oscillators coupled to a single individual quantum system. These systems offer radically new possibilities for the fabrication of extremely sensitive and ultra-compact optomechanical transducers, which can serve as position sensors or nano engines.The hybrid system investigated in this work consists of a single semiconducting quantum dot (QD) embedded in a vibrating photonic wire. It has been shown in the team, a few years ago, that the transition energy of the QD depends on the strain generated by the wire oscillations.In this thesis, we demonstrate the reverse effect, where each photon emitted by the QD comes along with a strain-induced force which drives the oscillations of the photonic wire. This realizes a nano engine run by a laser-driven single quantum object. The effect has been coined “Quantum Hammer effect”. This result opens the possibility for the future realization of a quantum state of motion via the transfer of the ”quantumness” of a two-level system towards the motion of a macroscopic mechanical oscillator
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Mlambo, O. S. "Characterisation of thick liquids using a vibrating transducer." Master's thesis, University of Cape Town, 2000. http://hdl.handle.net/11427/5159.
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Includes bibliographical referencesThis report describes in detail all the work carried out to reach the main objective of this thesis project, which is to develop a tuning fork into a portable instrument used for the characterisation of thick liquids based on their density and viscosity.
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Lee, Joon Pyo. "Ultrasonic transducer modeling in homogeneous and nonhomogeneous media." Thesis, The University of Arizona, 2001. http://hdl.handle.net/10150/278777.
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Ultrasonic transducer modeling is important and fundamental research for nondestructive testing of materials. Traditionally, in most nondestructive evaluation applications, the ultrasonic transducers are modeled as point sources generating spherical wave fronts, line sources generating cylindrical wave fronts, or planar surfaces generating plane wave fronts. In reality, the transducer front face has finite dimensions; it is neither point source nor planar source. This study shows how the ultrasonic field in the neighborhood of a transducer with finite dimension varies in homogeneous and nonhomogeneous media. In this thesis, the pressure variation in front of a transducer face is computed for the following three situations: (1) the transducer is immersed in a homogeneous fluid; (2) the transducer is near a fluid-fluid interface; and (3) the transducer is near a fluid-solid interface using Distributed Point Source Method For the nonhomogeneous fluid medium, both normal incidence and oblique incidence cases have been studied.
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Dias, Mateus Botani de Souza. "Construção de um transdutor quase-estatíco de tensão mecânica em propriedades magnéticas, aplicado a Liga (Fe0,8Al0,2)98.B2." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/97/97134/tde-24072014-152039/.
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No presente trabalho, foi construído um transdutor para medir as variações da indução magnética (B) e magnetostricção (?) de materiais ferromagnéticos macios em função de campo magnético aplicado (H) (voltagem V) e tensões mecânicas (?). O transdutor possui duas bobinas de excitação ligadas a uma fonte de corrente/voltagem (para aplicar o campo magnético no elemento magnetostrictivo) e um núcleo magnético, para concentrar o fluxo magnético no material ferromagnético. A magnetostricção é medida por extensômetria, a tensão mecânica é aplicada por uma máquina de ensaios universal (EMIC), a indução magnética é medida utilizando uma bobina de captura conectada a um fluxímetro e a aquisição dos dados foi realizada por um programa em Labview. O sistema mede curvas de M vs V e ? vs V para ? constante e também M vs ? e ? vs ? para V constante. A partir dessas curvas, é possível adquirir a sensibilidade do material e analisar a sua viabilidade em aplicações como sensores e atuadores. Utilizando este transdutor, foi possível caracterizar uma liga de FeAlB e comparar com uma amostra de GALFENOL, que é o material mais usado desta classe. As ligas apresentam sensibilidades (acima de 10 MPa) da ordem de 0,020 T/MPa para o GALFENOL e 0,012 T/MPa para a liga de FeAlB. Considerando que a liga de FeAlB não apresenta a melhor composição química, há muitas coisas para estudar ainda, como diferentes composições químicas e o processamento adequado para obter a textura desejada.In the present research, a transducer was built to measure the changes of magnetic induction (B) and magnetostriction (?) for soft ferromagnetic materials in function of applied magnetic field (H) (voltage V) and mechanical stress (?).The transducer comprises two excitation coils connected at a current/voltage supply (to apply the magnetic field in the magnetostrictive element) and a magnetic core, to concentrate the magnetic flux in the ferromagnetic material. The magnetostriction is measured by strain gauges, the mechanical stress is applied by a material test system (EMIC), the magnetic induction is measured using a pick-up coil connected to a fluxmeter and the acquisition of the data was measured by a Labview software. These systems measure the curve B vs. V and ? vs. V for constant ? and B vs. ? e ? vs. ? for constant V. From this curves, it is possible to acquire the material´s sensibility and analyse the feasibility of then in application like sensor and actuators. Using this transducer, it was possible to characterize a FeAlB alloy and to compare it with a GALFENOL sample, which is the most used material of this class. The alloys show sensibility (up to 10 MPa) about 0,020 T/MPa to the GALFENOL and 0,012 T/MPa to FeAlB alloy. If we consider that the FeAlB alloy does not have the best chemical composition to reach the higher magnetostriction, there is a lot o thing to study, like different composition and the appropriate processing to obtain the desired texture.
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Whitehead, Neil. "Static and rotational non contact torque measurement utilising a mechanical resonator providing a frequency output." Thesis, Brunel University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367860.
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Wu, Xia. "Theoretical evaluation of moderately focused spherical transducers and multi-focus acoustic lens/transducer combinations for high intensity focused ultrasound thermal therapy." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/MQ63114.pdf.
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Paul, Van Emburg David. "Finite element model of a capacitive transducer for measuring surface motion." Thesis, Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/17553.
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Medina, Jimmy Ernesto San Miguel. "Modelagem de ensaios não destrutivos por ultra-som utilizando o método dos elementos finitos." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/3/3132/tde-15022006-161038/.
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Os modelos existentes de propagação de ondas de ultra-som em meios líquidos e sólidos consideram a geração e recepção das ondas produzidas por transdutores simulados segundo o modelo do pistão plano ou com excitações cuja amplitude varia radialmente no pistão. Esses modelos são simplificados e não explicam completamente o comportamento real de transdutores de ultra-som interagindo com líquidos e sólidos. As verificações experimentais de propagação da onda de ultra-som em meios líquidos mostram que a onda de borda é diferente da onda plana. Observa-se também a existência de outras ondas não previstas nos modelos anteriores. Essas ondas são conhecidas como ondas head. A utilização do método dos elementos finitos (MEF) para a modelagem de propagação de ondas de ultra-som, incluindo o transdutor piezelétrico, permite a obtenção de resultados realísticos, conseguindo assim descrever com maior precisão o comportamento do transdutor e das ondas de ultra-som se propagando em diferentes meios e interagindo com defeitos que se comportam como refletores. Apesar disso, os resultados desses modelos dependem das características precisas dos materiais que compõem o transdutor. O transdutor de ultra-som é composto por uma cerâmica piezelétrica, por camadas de casamento e de retaguarda que geralmente são compósitos de epóxi com alumina e epóxi com tungstênio respectivamente, e pelo encapsulamento. Neste trabalho é analisada a resposta transiente de um transdutor circular de 2 MHz, com diâmetro de 12,7 mm, banda larga. O modelo do transdutor foi implementado com o método de elementos finitos. A análise transiente pelo MEF é implementada com o software ANSYS. Na primeira parte do trabalho o transdutor é analisado no modo de transmissão em água. Os resultados do modelo com MEF foram comparados com os resultados do modelo do pistão plano e com verificações experimentais obtidas em tanque de imersão com um hidrofone tipo agulha. Na segunda parte é realizada a análise do transdutor operando em modo pulso-eco radiando em peças de teste com e sem defeito, utilizando acoplamento direto e acoplamento por buffer de água. Os resultados do MEF apresentam boa concordância com os resultados obtidos experimentalmente.Simple models for ultrasonic wave propagation in liquid and solid media consider the wave generation and reception by transducers that behave as plane pistons. These models are simplified and they do not explain completely the behavior of an ultrasonic transducer when interacting with other media. Experimental verifications of ultrasonic wave propagation in liquid show that the pressure amplitude of the edge wave is different from the plane wave. Also it is observed the existence of other types of waves not foreseen in these previous models. These waves are known as head waves. More realistic models for ultrasonic wave propagation are obtained using the finite element method (FEM). These models include the piezoelectric transducer, thus, describing with higher precision the behavior of the transducer and the ultrasonic waves propagating in different mediums and interacting with defects. The precision of the models depends on the accurate determination of the mechanical and electrical properties of the involved materials. The ultrasonic transducer is composed by a piezoelectric ceramic, a matching layer and a backing layer that are generally made by epoxy/alumina and epoxy/tungsten composites respectively. In this work it is analyzed the transient response of a circular transducer of 12.7 mm diameter and 2 MHz center frequency. The transducer model was implemented with the finite element method. The FEM transient analysis was executed in the ANSYS software. In the first part of the work the transducer is analyzed in transmission mode in water and the MEF results are compared with the plane piston model and with experimental verifications using a hydrophone. In the second part it is carried at the transducer analysis operating in pulse-echo mode radiating into test pieces with and without defects, using direct and water buffer coupling. The MEF results show good agreement with the results obtained experimentally in the laboratory.
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Garcia, Welington Luis Codinhoto [UNESP]. "Teds-easy - descrição automática de transducer electronic data sheet." Universidade Estadual Paulista (UNESP), 2014. http://hdl.handle.net/11449/111113.
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000800354.pdf: 2158636 bytes, checksum: 30cb8216f1fbaa6275408b282df9f779 (MD5)Neste trabalho, apresenta-se uma ferramenta para descrição automática de TEDS (Transducer Electronic Data Sheet), facilitando a configuração de transdutores em uma rede de sensores inteligentes de acordo com o padrão IEEE 1451. As TEDS são tabelas virtuais definidas no padrão IEEE 1451, que contém a descrição dos transdutores. No desenvolvimento desta ferramenta, denominada de TEDS-EASY, utilizou-se a linguagem de programação web JSP (Java Server Pages) e sistema de banco de dados PostGreeSQL. Utilizou-se também a UML (Unified Modeling Language) para realizar a modelagem do projeto. Foram realizados testes com o sistema TEDS-EASY, a fim de validar as TEDS geradas por meio de descrições manuais e descrições encontradas na literatura, comparando com a descrição obtida ao utilizar a ferramenta de descrição de TEDS apresentada neste trabalho
This work presents a tool for automatic description of TEDS (Transducer Electronic Data Sheet), facilitating the configuration of transducers on a network of smart sensors according to the IEEE 1451 standard.'s TEDS are virtual tables defined in the IEEE 1451 standard containing the description of the transducers. In developing this tool called TEDS-EASY used the language of web programming JSP (Java Server Pages) and database system PostgreSQL database. We also used the UML (Unified Modeling Language) to perform the modeling project. Tests with TEDS-EASY system were performed in order to validate the TEDS generated through manual descriptions and descriptions found in the literature, comparing with the description obtained when using the tool for describing TEDS show in this project
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Nordlund, Erik. "The Four-Quadrant Transducer System : for Hybrid Electric Vehicles." Doctoral thesis, Stockholm, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-214.
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Pross, Alexander. "Design of a saturated analogue and digital current transducer." Thesis, Coventry University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.247454.
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Ye, Simon. "Acoustic mixing in microfluidic chip using a Langevin transducer." Thesis, KTH, Tillämpad fysik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-156644.
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Algehyne, Ebrahem Ateatullah. "Theoretical analysis of a fractal ultrasonic transducer using renormalisation." Thesis, University of Strathclyde, 2018. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=30782.
Full textAbstract:
To ensure the safe operation of many safety critical structures such as nuclear plants, aircraft and oil pipelines, non-destructive imaging is employed using piezoelectric ultrasonic transducers. These sensors typically operate at a single frequency due to the restrictions imposed on their resonant behaviour by the use of a single length scale in the design. To allow these transducers to transmit and receive more complex signals it would seem logical to use a range of length scales in the design so that a wide range of resonating frequencies will result. In this thesis we derive a mathematical model to predict the operating characteristics of an ultrasound transducer that achieves this range of length scales by adopting a fractal architecture; the fractal in this case being the Sierpinski gasket. Expressions for the electrical and mechanical fields that are contained within this structure are expressed in terms of a finite element basis. A renormalisation approach is then used to calculate the key components from the discrete matrices that arise. The propagation of an ultrasonic wave in this transducer is then analyzed and used to derive expressions for the non-dimensionalised electrical impedance and the transmission and reception sensitivities as a function of the driving frequency. Comparing these key performance measures of the fractal transducer to an equivalent standard (Euclidean) design shows that the fractal devices have a significantly higher reception sensitivity and a significantly wider bandwidth.
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Roberts, Megan Johnson. "Design and fabrication of a flexible membrane ultrasound transducer." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/120263.
Full textAbstract:
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 143-152).
Wearable ultrasound sensing could enable novel medical diagnostics by facilitating continuous, real-time, and direct measurement of physiological phenomena, such as blood pressure. Currently, ultrasound is not used in wearable health sensing applications because clinical ultrasound systems are expensive, bulky, and require high operating power. Realizing wearable ultrasound therefore requires significant reductions in cost, size, and power consumption. Manufacturing cost is of particular concern because sensors are frequently incorporated into consumer goods, where cost is a key driver of technology adoption. Toward that goal, this thesis explored the first steps toward the opportunity to fabricate low-cost ultrasound transducers by contact printing. Contact printing was selected because it could be scaled for high-throughput manufacturing, and it could be performed at ambient temperature and pressure. For this thesis, a capacitive microscale ultrasound transducer was fabricated by contact printing a gold-parylene composite flexible membrane onto a silicon chip substrate. Significant challenges with the adhesion between the membrane and the chip were overcome during fabrication process development and a high yield process for the contact printing step was developed. The transducer was characterized for electromechanical performance. The first mode resonant frequency of the transducer was 2.2MHz, with a 2MHz bandwidth, placing it in the range of interest for medical ultrasound applications (typically 1-15MHz). These results demonstrate that flexible membrane ultrasound transducers can be fabricated. Furthermore, they illuminate a path toward wearable ultrasound sensing and more broadly, flexible medical devices.
by Megan Johnson Roberts.
Ph. D.