Dissertations / Theses on the topic 'Enhanced measurement'
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Akmal, Muhammad. "An enhanced modulated waveform measurement system." Thesis, Cardiff University, 2011. http://orca.cf.ac.uk/16154/.
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The microwave devices and circuits need to be characterized prior to being employed in the design of systems and components. Unfortunately the measurement systems required to characterize the microwave devices and circuits have not kept pace with the emerging telecommunication technologies demands. This has resulted into a situation where either the circuits being employed in the components are unoptimized or the yield and turn-around of optimized circuits are slow. One of the contributing factors of such situations is the limitations of the existing measurement systems to scale up in performance to fulfil the necessary requirements. This thesis presents an enhanced multi-tone, time domain waveform measurement and engineering system. The presented system allows for a more considered, and scientific process to be adopted in the characterisation and measurement of microwave power devices for modern day communications systems. The main contributions to the field of research come in two areas; firstly developments that allow for accurate time domain measurement of complex modulated signals using commercially available equipment; and secondly in the area of active impedance control, where significant developments were made allowing active control of impedance across a modulated bandwidth. The first research area addressed is the fundamental difficulty in sampling multi-tone waveforms, where the main achievements have been the realisation of a high quality trigger clock for the sampling oscilloscope and a “Time Domain Partitioning” approach to measure and average multi-tone waveforms on-board. This approach allows the efficient collection of high quality vectoral information for all significant distortion terms, for all bands of interest. The second area of research investigated suitable impedance control architectures to comprehensively investigate out-of-band impedance effects on the linearity performance of a device. The ultimate aim was to simultaneously present independent, baseband impedances to all the significant baseband (IF) frequency components and to 2nd harmonic that result from a multi-tone excitation. The main achievement in this area was the ability of the enhanced measurement system to present the broadband impedance. At baseband this has been achieved in the time domain using a single arbitrary waveform generator (AWG) to synthesise the necessary waveforms to allow a specific IF impedance environment to be maintained across a wide IF bandwidth. To engineer the RF out-of-band load terminations at RF frequencies and to emulate specific power amplifier modes, a Tektronix AWG7000 Arbitrary Waveform Generator was used to deliver the desired impedances, practically fulfilling the wideband application requirements for reliable device characterisation under complex modulated excitations.
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Gray, Victoria Louise. "Enhanced methods of microbial measurement and detection." Thesis, Cardiff University, 2006. http://orca.cf.ac.uk/56173/.
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This study demonstrates the effects of different peptones, made from different biological sources and produced by numerous manufacturers, on the growth dynamics and morphology of various bacteria. The effects these differing growth medium constituents have upon the outcome of microbiological procedures, from identification of bacterial species to public health diagnostics, is of great significance. Peptones were assessed as a constituent of the pre-enrichment broth buffered peptone water. Generation times and yields at 24 h were measured using optical density techniques and were significantly affected by the type of peptone employed as nutrient source. Growth characteristics indicated that where peptones performed poorly, this was a result of poor nutrient quantities and not due to the presence of endogenous inhibitors. It is shown that Salmonella exhibit morphological differences, including cultures. which lack flagella and are consequently non-motile, dependent on the peptone constituents of the culture medium. Transfer of a flagellate Salmonella from nutritionally poor media into rich nutrient broth allowed flagella synthesis: indicating that the aflagellate form is still able to produce flagella. Amino acid sequencing of the peptones producing aflagellate organisms showed a relatively low tyrosine concentration: addition of tyrosine and glucose to these media produced flagellate salmonellae. Identification of the Salmonella serotypes is based on flagellar and somatic antigens therefore the absence of flagella may consequently affect complete identification of the serotype. Antibiotic susceptibility of the Enterobacteria was shown to be markedly affected by peptone, causing breakpoints to vary from sensitive to resistant. Thus the inclusion of different, undefined ingredients in growth media has a considerable effect upon the ability of the medium to enumerate bacteria furthermore these medium constituents affect the outcome of scientific research and should be carefully considered before work is commenced.
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Lloyd, Natasha. "Clutter measurement and reduction for enhanced information visualization." Link to electronic thesis, 2005. http://www.wpi.edu/Pubs/ETD/Available/etd-011206-232808/.
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Lloyd, Natasha. "Clutter Measurement and Reduction for Enhanced Information Visualization." Digital WPI, 2006. https://digitalcommons.wpi.edu/etd-theses/67.
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The effectiveness of information visualization largely depends on the ease and accuracy with which users can access the information. Visual clutter in a display can detract from a user's ability to properly read the information. An ideal visualization needs to maximize the visibility of patterns and structure and minimize the clutter present. Thus far, there has been surprisingly little work done in finding quantitative ways to measure clutter in information visualizations. The goal of this project was to create clutter measurement and reduction techniques that minimize the presence of visual clutter and maximize a user's ability to accurately read the data. These methods were tested and evaluated on a number of visualizations depicting domestic air traffic data.
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Huang, James, and James Huang. "Knowledge Enhanced Compressive Measurement Design: Detection and Estimation Tasks." Diss., The University of Arizona, 2016. http://hdl.handle.net/10150/621121.
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Compressive imaging exploits the inherent sparsity/compressibility of natural scenes to reduce the number of measurements required for reliable reconstruction/recovery. In many applications, however, additional scene prior information beyond sparsity (such as natural scene statistics) and task prior information may also be available. While current efforts on compressive measurement design attempt to exploit such scene and task priors in a heuristic/ad-hoc manner, in this dissertation, we develop a principled information-theoretic approach to this design problem that is able to fully exploit a probabilistic description (i.e. scene prior) of relevant scenes for a given task, along with the appropriate physical design constraints (e.g. photon count/exposure time) towards maximizing the system performance. We apply this information-theoretic framework to optimize compressive measurement designs, in EO/IR and X-ray spectral bands, for various detection/classification and estimation tasks. More specifically, we consider image reconstruction and target detection/classification tasks, and for each task we develop an information-optimal design framework for both static and adaptive measurements within parallel and sequential measurement architectures. For the image reconstruction task we show that the information-optimal static compressive measurement design is able to achieve significantly better compression ratios (and also reduced detector count, readout power/bandwidth) relative to various state-of-the-art compressive designs in the literature. Moreover, within a sequential measurement architecture our information-optimal adaptive design is able to successfully learn scene information online, i.e. from past measurement, and adapt next measurement (in a greedy sense) towards improving the measurement information efficiency, thereby providing additional performance gains beyond the corresponding static measurement design. We also develop a non-greedy adaptive measurement design framework for a face recognition task that is able to surpass the greedy adaptive design performance, by (strategically) maximizing the the long-term cumulative system performance over all measurements. Such a non-greedy adaptive design is also able to predict the optimal number of measurements for a fixed system measurement resource (e.g. photon-count). Finally, we develop a scalable (computationally) information-theoretic design framework to an X-ray threat detection task and demonstrate that information-optimized measurements can achieve a 99% threat detection threshold using 4x fewer exposures compared to a conventional system. Equivalently, the false alarm rate of the optimized measurements is reduced by nearly an order of magnitude relative to the conventional measurement design.
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Moncaleano, Sebastian. "Examining the Comparative Measurement Value of Technology-Enhanced Items:." Thesis, Boston College, 2021. http://hdl.handle.net/2345/bc-ir:109086.
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Thesis advisor: Michael RussellThe growth of computer-based testing over the last two decades has motivated the creation of innovative item formats. It is often argued that technology-enhanced items (TEIs) provide better measurement of test-takers’ knowledge, skills, and abilities by increasing the authenticity of tasks presented to test-takers (Sireci & Zenisky, 2006). Despite the popularity of TEIs in operational assessments, there remains little psychometric research on these innovative item formats. Claims regarding their potential to provide better measurement are seldomly explored. This dissertation adds to this limited body of research by developing theory and proposing a methodology to compare TEIs to traditional item formats. This study investigated how to judge the comparative measurement value (CMV) of two drag-and-drop technology-enhanced formats (classification and rank-ordering) relative to stem-equivalent multiple-choice items. Items were administered to a sample of adults and results were calibrated using a 2-parameter logistic IRT model. Moreover, the utility of the TEIs was evaluated according to the TEI Utility Framework (Russell, 2016). Four indicators were identified as the most valuable characteristics to judge CMV and then combined into a hierarchical decision protocol. When applied, this protocol provides a CMV judgment and a recommendation of the preferred item format. Applying the protocol to the items revealed that most TEIs examined in this study showed decreased CMV, indicating that in a real-life scenario the multiple-choice format would be favored for most of these item pairs. Recommendations for the use of the CMV protocol and directions of future related research are discussed
Thesis (PhD) — Boston College, 2021
Submitted to: Boston College. Lynch School of Education
Discipline: Educational Research, Measurement and Evaluation
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Westerlund, Joel. "Enhanced Distance Learning: A Measurement Tool for Electronics Courses." Thesis, Uppsala universitet, Institutionen för informationsteknologi, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-424292.
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Learning outcomes in electronic courses often involve objectives that require hands-on experience in a laboratory environment. Thus, transforming such a course to be suited for distance learning might prove problematic. Using video lectures is possible but deprives the students of the ability to experiment on their own. The aim of this thesis was to mitigate the problem by developing an affordable platform providing the basic functionality of standard laboratory equipment designed for easy distribution. The resulting hardware is able to produce an 8 Vpp output signal in the range of 1 Hz to 100 kHz with a high level of accuracy both in terms of voltage level and frequency. The signal may be applied to a circuit and analyzed using two analog input channels, displaying the results on the screen of a computer connected with a USB cable. The hardware interaction is performed using a graphical interface developed to function on all major operating systems and provide a user-friendly environment. Some interference were experienced on high frequencies but we believe that the problems can be fixed with a minor redesign of the circuit board. The evaluation shows that the performance is within the specified requirements and after testing some of the typical use cases the system is concluded to be sufficient for the intended purposes.
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Radjenovic, Aleksandra. "Measurement of physiological variables by dynamic Gd-DTPA enhanced MRI." Thesis, University of Leeds, 2003. http://etheses.whiterose.ac.uk/356/.
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Abnormal angiogenesis is characterised by the alteration of physiological variables such as capillary permeability and fractional volume of the extravascular extracellular space. The aim of the work presented in this thesis was to investigate the feasibility of non-invasive measurement of these physiological variables through quantitative analysis of dynamic Gd-DTPA enhanced MRI (DEMRI) acquired using standard imaging hardware within a clinical setting. A method for quantitative analysis of DEMRI (QDEMRI) was developed and implemented on a standard personal computer platform using a set of programs written in the C programming language. The method includes pharmacokinetic modelling of Gd-DTPA kinetics based on the modification of existing approaches and moving-window algorithms for the measurement of black-box quantifiers of DEMRI. The measurements were performed in two angiogenesis dependent diseases: breast cancer and rheumatoid arthritis (RA). In a study involving QDEMRI analysis of 59 primary invasive breast carcinomas, a significant relationship between capillary permeability-related QDEMRI variables and tumour grade was found. In a randomised controlled study of early RA in metacarpophalangeal joints, a significant reduction in the QDEMRI variable which reflects fractional volume of the extravascular extracellular space was found three months after the start of therapy in 20 patients treated with methotrexate and intra-articular methylprednisolone injections, whereas it remained constant in a control group of 17 patients who were treated with slow-acting methotrexate only. A significant reduction in the permeability-related QDEMRI variable was detected in 17 patients treated with leflunomide four months after the start of treatment whilst it remained unchanged in 17 patients treated with methotrexate in a randomised controlled study of established RA of the knee joint. The results obtained in this work indicate that the proposed QDEMRI method can be used in its present form to monitor treatment-induced changes in angiogenesis dependent diseases. Further work is needed to render these measurements fully independent of DEMRI acquisition settings and allow the evaluation of individual lesions.
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Thomas-Peter, Nicholas. "Quantum enhanced precision measurement and information processing with integrated photonics." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:7bd47582-d32f-4d07-9e90-4978c32cf14e.
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Photons have proven to be an effective test-bed for the fundamental concepts and elements of quantum-enhanced technologies. As systems become increasingly complex, however, practical considerations make the traditional approach of bulk optics and free-space propagation progressively more difficult. The major obstacles are the physical space necessary to realise and operate such a complex system, its stability, and maintaining low losses. In order to address these issues, quantum optical technologies can take a cue from their classical counterparts and look towards an integrated architecture to provide miniaturisation, greatly enhanced stability, less alignment, and low loss interfaces between different system components. In this thesis the feasibility of chip-based waveguides as a platform for metrology and information processing will be explored. In Part I, the necessary criteria for a metrology system to out-perform its classical counterpart will be investigated. It will be found that loss is a major barrier to this aim and, critically, that it is unlikely to have been achieved to date by any experiment which consumes resources of a fixed photon number. The issue of loss will be addressed by developing a scalable heralded source of a class of entangled photonic states which are both robust to losses and practically feasible to prepare. A novel tomographic technique will be developed to characterize these states and it will be explicitly demonstrated how it is possible to beat some bounds on classical performance without being able to out-perform a comparable classical system. Finally, a proof of principle demonstration of a waveguide-based interferometer with an integrated phase-shifter will be undertaken. It will be shown that the device preserves quantum interference, making it suitable for use in quantum-enhanced metrology applications. In Part II, integrated optics in the context of information processing will be discussed. First, a novel characterization technique will be developed which enables the behaviour of complex circuits to be predicted. The technique is independent of loss in the device being characterized. A method of simulating these circuits will be outlined that takes advantage of the computational speed-up available from parallelisation and sparse matrix operations. A key increase in complexity for integrated photonic systems will be demonstrated by showing quantum interference of three photons from two separate sources in eight spatial modes. The resulting interference has a visibility which beats all possible classical interference visibilities for similar circuits. Finally, a fully integrated waveguide-coupled photon-number-resolving detector will be developed and demonstrated. This proof of concept demonstration will show good resolution of different photon number events. The device will be modelled and routes to high efficiency operation will be explored.
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Ashton, Phillip Michael. "Exploiting phasor measurement units for enhanced transmission network operation and control." Thesis, Brunel University, 2014. http://bura.brunel.ac.uk/handle/2438/9063.
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In order to achieve binding Government targets towards the decarbonisation of the electricity network, the GB power system is undergoing an unprecedented amount of change. A series of new technologies designed to integrate massive volumes of renewable generation, predominantly in the form of offshore wind, asynchronously connecting to the periphery of the transmission system, are transforming the requirements of the network. This displacement of traditional thermal generation is leading to a significant reduction in system inertia, thus making the task of system operation more challenging. It is therefore deemed necessary to develop tools and technologies that provide far greater insight into the state of the power system in real-time and give rise to methods for improving offline modelling practices through an enhanced understanding of the systems performance. To that extent PMUs are seen as one of the key enablers of the Smart Grid, providing accurate time-synchronised measurements on the state of the power system, allowing the true dynamics of the power system to be captured and analysed. This thesis provides an analysis of the existing PMU deployment on the GB transmission system with a view to the future system monitoring requirements. A critical evaluation and comparison is also provided on the suitability of a University based Low Voltage PMU network to further enhance the visibility of the GB system. In addition a novel event detection algorithm based on Detrended Fluctuation Analysis is developed and demonstrated, designed to determine the exact start time of a transmission event, as well as the suitability of such an event for additional transmission system analysis, namely inertia estimation. Finally, a reliable method for the estimation of total system inertia is proposed that includes an estimate of the contribution from residual sources, of which there is currently no visibility. The proposed method identifies the importance of regional inertia and its impact to the operation of the GB transmission system.
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Butler, Timothy Joseph Alexander. "Cavity enhanced spectroscopy methods for measurement of optical properties of aerosol particles." Thesis, University of Bristol, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.492653.
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A continuous wave distributed feedback diode laser operating in the near infrared at wavelengths close to 1650 nm has been used to measure the extinction of light by aerosol particles. The technique of optical feedback cavity ring-down spectroscopy (OF-CRDS) was used to enable measurement of CRDS events at a repetition rate of 1.25 kHz.
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Hadden, J. P. "Photonic structures and techniques for enhanced measurement of spin qubits in diamond." Thesis, University of Bristol, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.664971.
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The negatively charged nitrogen vacancy centre is a promising candidate for use as a single photon source for linear optical quantum information, and as a solid state spin for solid state quantum information and room temperature magnetometry. However low photon collection efficiency is a problem for each of these applications. We demonstrate how photon losses due to refraction can be eliminated through the use of Solid Immersion Lenses (SILs) nano-fabricated on the surface of diamond. Coherent electron spin manipulation and readout is demonstrated on NV- centres under SILs. We show initial investigations into the effects of FIB fabrication on the NV- centre's coherence time, and demonstrate unitary quantum process discrimination on between two non orthogonal processes. In order to improve collection efficiency further it is necessary to couple NV- centres to optical micro cavities. This requires a higher degree of precision in the measurement of the NV- centres position than is possible using conventional confocal microscopy. We investigate spectral self interferometric microscopy as a method for precision measurement of the depth of an NV- centre. Finally we show coherent manipulation of photons emitted from a near infra-red colour centre in diamond using a single integrated waveguide chip. This is used to verify wave particle duality of the photons.
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Scherger, Jacob D. "Expanding Tip Enhanced Raman Spectroscopy: Blinking Measurements and Alternative Probe Materials." University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1510657402180872.
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Hikmet, Noraddin Feria. "Measurement and validation of urinary cystatin C by particle-enhanced turbidimetric immunoassay on Architect ci8200." Thesis, Uppsala universitet, Institutionen för medicinsk biokemi och mikrobiologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-154713.
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Cystatin C, a 13 kDa low molecular weight protein is an inhibitor of cysteine proteases. Due to its low molecular weight and positive charge at physiological pH, it is freely filtered by the glomerulus and catabolized after reabsorption by proximal tubular cells with a low concentration (0.03-0.3 mg/L) in urine amongst healthy subjects. Urinary cystatin C is a potential biomarker detection of acute kidney injury (AKI) in the acute phase when patients are submitted to the intensive care unit. The aim in this report was to perform a full method validation of urinary analysis of cystatin C on a high throughput chemical analyzer by particle-enhanced turbidimetric immunoassay (PETIA) at the University Hospital in Uppsala, Sweden. The antigen excess, linearity, lower limit of quantification (LoQ), recovery, assay precision, stability and interference caused by haemoglobin was evaluated. No hook effect was observed, the assay was linear over the studied interval <0.001-0.950 mg/L with a regression of R2=0.9994. The LoQ was calculated to 0.020 mg/L with a coefficient of variation (CV) ≤10% which was considered acceptable. The assay had a recovery between 93-100% and the assay precision had a total CV <3.5%. Cystatin C is stable for 3 days in room temperature and 14 days in +4C. The assay did not show any major interference with haemoglobin. The urinary cystatin C showed good precision and performance characteristics by measurements using PETIA all of which is a necessary qualification for a biomarker at a 24-h running routine laboratory.
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Tsai, De-Hao. "Understanding electric field-enhanced transport for the measurement of nanoparticles and their assembly on surfaces." College Park, Md.: University of Maryland, 2007. http://hdl.handle.net/1903/7716.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2007.Thesis research directed by: Dept. of Materials Science and Engineering . Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Higginbotham, Steven. "Enhanced Electrical Impedance Sensing of Biological Cells Using Travelling Wave Dielectrophoresis Manipulation." Thesis, Griffith University, 2007. http://hdl.handle.net/10072/367544.
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Electrokinetics involves techniques of applying forces and torques to fluids or suspended microscopic particles like biological cells, by exploiting their electrical properties and their interactions with electric fields. This has been demonstrated many times to have significant applications in lab-on-a-chip systems. Biological cells and other microparticles are dielectrically-heterogeneous structures, and therefore each different particle has a distinct dielectric frequency-response signature. This dielectric distinction allows sub-populations of particles to be separated by different criteria such as cell species or physiological state, by applying alternating current (AC) electric fields at frequencies where the responses differ between sub-populations.
Electrokinetic manipulation in the form of dielectrophoresis (DEP) can be used to selectively (usually by species or physiological state) trap biological microparticles to a set of electrodes through which impedance sensing can be used to sense their concentration. This technique has been demonstrated many times in the literature, and has been called Dielectrophoretic Impedance Measurement (DEPIM). This is most effective when a particle suspension is flowing past the electrodes so that the particles can be trapped out of the fluid as it passes, due to the local nature of the DEP forces.
Travelling wave dielectrophoresis (TWD) is a technique which can be used to move cells in a more continuous manner over a large array of electrodes, to a subset of electrodes, or to regions adjacent to an array of electrodes, within a stationary suspending medium. Travelling wave dielectrophoresis has been demonstrated in the literature to be useful for concentrating suspended particles such as biological cells, using single-layer fabricated microelectrodes with
spiral geometries, to a single area from a particle suspension. This concentration can also be done selectively, as different particles have different responses versus applied phase-quadrature signal frequency.
Absent from the literature, are devices which take advantage of this concentration ability in conjunction with impedance sensing or impedance spectroscopy, to sense the suspended particles as they are concentrated.
This thesis presents microfabricated devices, and associated electronic systems which use techniques involving travelling wave dielectrophoresis, as-opposed to dielectrophoresis, to selectively concentrate particles within a stationary fluid, to a subset of electrodes through which electrical impedance spectroscopy is used to determine particle sub-population concentrations.
Several different device designs are briefly outlined and discussed, as well as associated signal processing electronic systems. A final single device design is described and testing of operation detailed. Testing of several different modes of operation of this device are discussed, including sensing the concentration of a single type of cell using a single phase-quadrature signal frequency, as well as using multiple phase-quadrature signal frequencies to separateand sense two different cell sub-populations.
These or similar devices could be used as sensors which could potentially be more selective and sensitive than DEPIM devices, and without requiring a fluid flow, such as that generated by a microfluidic system.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Engineering
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Colatat, Mahyulee Chang. "Estimating performance mean and variability with distributional rating scales a field study towards enhanced performance measurement /." Bowling Green, Ohio : Bowling Green State University, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=bgsu1206385486.
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Leitis, Karsten. "Analogue hardware based algorithm for low-power and low-voltage position measurement systems with enhanced resolution." Thesis, City University London, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.412676.
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Mosalaei, Homeira. "Measurement of renal blood flow in normal and obstructed kidney using dynamic contrast enhanced x-ray computed tomography." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0005/MQ30812.pdf.
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Henderson, Elizabeth. "Measurement of blood flow, blood volume and capillary permeability in breast tumours using contrast-enhanced magnetic resonance imaging." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0020/NQ58134.pdf.
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Golshani, Mohammad. "Novel performance evaluation of information and communication technologies to enable wide area monitoring systems for enhanced transmission network operation." Thesis, Brunel University, 2015. http://bura.brunel.ac.uk/handle/2438/11918.
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The penetration of renewable energy sources has increased significantly in recent years due to the ongoing depletion of conventional resources and the transition to a low carbon energy system. Renewable energy sources such as wind energy are highly intermittent and unpredictable in nature, which makes the operation of the power grid more dynamic and therefore more complex. In order to operate the power system reliably under such conditions, Phasor Measurement Units (PMUs) through the use of satellite technology can offer a state-of-the-art Wide Area Monitoring System (WAMS) for improving power system monitoring, control and protection. They can improve the operation by providing highly precise and synchronised measurements near to real-time with higher frequency and accuracy. In order to achieve such objectives, a high-speed and reliable communications infrastructure is required to transfer time-critical PMU data from remote locations to the control centre. The signals measured by PMUs are transmitted across Local and Wide Area Networks, where they may encounter excessive delays. Signal delays can have a disruptive effect and make applications at best inefficient and at worse ineffective. The main research contribution of this thesis is the performance evaluation of communication infrastructures for WAMS. The evaluation begins from inside substations and continues over wide areas from substations to control centre. Through laboratory-based investigations and simulations, the performance of communications infrastructure in a typical power system substation has been analysed. In addition, the performance evaluation of WAMS communications infrastructure has been presented. In the modelling and analysis, an existing WAMS as installed on the GB transmission system has been considered. The actual PMU packets as received at the Phasor Data Concentrator (PDC) were captured for latency analysis. A novel algorithmic procedure has been developed and implemented to automate the large-scale latency calculations. Furthermore, the internal delays of PMUs have been investigated, determined and analysed. Subsequently, the WAMS has been simulated and detailed comparisons have been performed between the simulated model results and WAMS performance data captured from the actual WAMS. The validated WAMS model has been used for analysing possible future developments as well as to test newly proposed mechanisms, protocols, etc. in order to improve the communications infrastructure performance.
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Heye, Anna Kathrin. "Measurement of subtle blood-brain barrier disruption in cerebral small vessel disease using dynamic contrast-enhanced magnetic resonance imaging." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/22929.
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Cerebral small vessel disease (SVD) is a common cause of strokes and dementia. The pathogenesis of SVD is poorly understood, but imaging and biochemical investigations suggest that subtle blood-brain barrier (BBB) leakage may contribute to tissue damage. The most widely-used imaging method for assessing BBB integrity and other microvascular properties is dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). DCE-MRI has primarily been applied in situations where contrast uptake in tissue is typically large and rapid (e.g. neuro-oncology); the optimal approach for quantifying BBB integrity in diseases where the BBB remains largely intact and the reliability of resulting measurements is unclear. The main purpose of this thesis was to assess and improve the reliability of quantitative assessment of subtle BBB disruption, in order to illuminate its potential role in cerebral SVD. Firstly, a systematic literature review was performed in order to provide an overview of DCE-MRI methods in the brain. This review found large variations in MRI procedures and data analysis methods, resulting in widely varying estimates of tracer kinetic parameters. Secondly, this thesis focused on the analysis of DCE-MRI data acquired in an on-site clinical study of mild stroke patients. After performing basic DCE-MRI processing (e.g. selection of a vascular input function), this work aimed to determine the tracer kinetic modelling approach most suitable for assessing subtle BBB disruption in this cohort. Using data-driven model selection and computer simulations, the Patlak model was found to provide accurate estimates of blood plasma volume and low-level BBB leakage. Thirdly, this thesis aimed to investigate two potential pitfalls in the quantification of subtle BBB disruption. Contrast-free measurements in healthy volunteers revealed that a signal drift of approximately 0.1 %/min occurs during the DCE-MRI acquisition; computer simulations showed that this drift introduces significant systematic errors when estimating low-level tracer kinetic parameters. Furthermore, tracer kinetic analysis was performed in an external patient cohort in order to investigate the inter-study comparability of DCE-MRI measurements. Due to the nature of the acquisition protocol it proved difficult to obtain reliable estimates of BBB leakage, highlighting the importance of study design. Lastly, this thesis examined the relationship between quantitative MRI parameters and clinical measurements in cerebral SVD, with a focus on the estimates of blood volume and BBB leakage obtained in the internal SVD patient cohort. This work did not provide evidence that BBB leakage in normal-appearing tissue increases with SVD burden or predicts disease progression; however, increased BBB leakage was found in white matter hyperintensities. Furthermore, this work raises the possibility of a role for blood plasma volume and dietary salt intake in cerebral SVD. The work described in this thesis has demonstrated that it is possible to estimate subtle BBB disruption using DCE-MRI, provided that the measurement and data analysis strategies are carefully optimised. However, absolute values of tracer kinetic parameters should be interpreted with caution, particularly when making comparisons between studies, and sources of error and their influence should be estimated where possible. The exact roles of BBB breakdown and other microvascular changes in SVD pathology remain to be defined; however, the work presented in this thesis contributes further insights and, together with technical advances, will facilitate improved study design in the future.
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Marklund, Sandra. "Feasibility Study of Phase Measurements of the Arterial Input Function in Dynamic Contrast Enhanced MRI." Thesis, Umeå University, Radiation Physics, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-23226.
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Acquired data from dynamic contrast enhanced MRI measurements can be used to non-invasively assess tumour vascular characteristics through pharmacokinetic modelling. The modelling requires an arterial input function which is the concentration of contrast agent in the blood reaching the volume of interest as a function of time. The aim of this work is testing and optimizing a turboFLASH sequence to appraise its suitability for measuring the arterial input function by measuring phase.
Contrast concentration measurements in a phantom were done with both phase and relaxivity techniques. The results were compared to simulations of the experiment conditions to compare the conformance. The results using the phase technique were promising, and the method was carried on to in-vivo testing. The in-vivo data displayed a large signal loss which motivated a new phantom experiment to examine the cause of this signal reduction. Dynamic measurements were made in a phantom with pulsatile flow to mimic a blood vessel with a somewhat modified turboFLASH sequence. The conclusions drawn from analyzing the data were used to further improve the sequence and this modified turboFLASH sequence was tested in an in-vivo experiment. The obtained concentration curve showed significant improvement and was deemed to be a good representation of the true blood concentration.
The conclusion is that phase measurements can be recommended over relaxivity based measurements. This recommendation holds for using a slice selective saturation recovery turboFLASH sequence and measuring the arterial input function in the neck. Other areas of application need more thorough testing.
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Hayford, Paula J. "Measurement of immediate gain in knowledge and long term change of behavior after attending an enhanced case management workshop." Online version, 2002. http://www.uwstout.edu/lib/thesis/2002/2002hayfordp.pdf.
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Anahory, Iolanda Vieira. "Improvement of a liquid phase blocking ELISA for enhanced detection and measurement of antibodies against the SAT3 serotype of FMDV." Diss., University of Pretoria, 2016. http://hdl.handle.net/2263/57304.
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Foot-and-mouth disease virus (FMDV) is the causative agent of one of the most serious infections of cloven-hoofed animals. An outbreak of FMD not only severely decreases livestock productivity, but also impacts on both the local and export trade of susceptible animals and their products. The Southern African Territories (SAT) types 1-3 are endemic to sub-Saharan Africa and display greater intratypic genomic and antigenic variation than the traditional Euro-Asian types. Southern Africa has an abundant wildlife, especially in National Parks and game reserves. Wildlife, particularly African buffalo (Syncerus caffer), is involved in virus maintenance and epidemiology of the disease. In communities within the proximity of National Parks and game reserves, the wildlife-livestock interface presents a challenge and poses difficulty to livestock disease eradication and control in Africa.
In this study, the influence of modifications to the reagents has on the specificity, sensitivity and repeatability of a LPBE, used for the detection of antibodies against FMD, was determined. The sensitivity of the LPBE is dependent on the antigen used in the test and the ability of the sera to cross-react with the antigen. The purified and non-purified virus used as antigen and the capture and detector antibodies were prepared and standardized for this purpose. An attempt was made to reduce the subtype-specificity of the LBPE by including antigens from all the relevant SAT3 strains.
A total of 515 sera from FMDV exposed cattle in Mpumalanga during 2011-2012; 1398 sera from unexposed cattle obtained during an FMD survey conducted in the Northern Cape, and 286 sera from FMDV vaccinated cattle next to the Kruger National Park (KNP) were tested with the improved ELISA. A statistical analysis was conducted to compare the results obtained with the newly developed ELISA and the current in house ELISA. The new assay has higher sensitivity for detecting antibodies in vaccinated animals compared to the standard LPBE. The test is specific and suitable for detection of antibodies, and plays a key role toward the control of FMD, specific and suitable for identification and typing of all SAT3 serotype across the range of the genetic variations in the SAT3 serotype of FMDV.Dissertation (MSc)--University of Pretoria, 2016.
tm2016
Veterinary Tropical Diseases
MSc
Unrestricted
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Chakravarthy, Pramod. "Silicon carbide coatings by plasma-enhanced chemical vapor deposition on silicon and polyimide substrates." Ohio : Ohio University, 1995. http://www.ohiolink.edu/etd/view.cgi?ohiou1179519920.
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Ayoub, Elie. "Caractérisation des effluents d’expérimentations EOR (Enhanced Oil Recovery) grâce à des techniques de microfluidique analytique." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS017.
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La récupération assistée du pétrole par voie chimique (cEOR, chemical Enhanced Oil Recovery) est l'une des méthodes utilisées pour répondre à la demande croissante de pétrole. Parmi les méthodes de cEOR, on retrouve la voie tensioactive. Cette dernière consiste à injecter une formulation aqueuse, contenant des tensioactifs, afin d’obtenir des tensions interfaciales ultra basses (typiquement < 10-2 mN / m) entre l’eau et le pétrole, et ainsi mobiliser le pétrole piégé par les forces capillaires dans le réservoir. Généralement, un scan de salinité est effectué en laboratoire afin de déterminer la salinité optimale (S*) de la formulation permettant l’obtention d’une tension interfaciale minimale. Ensuite, la formulation optimale est évaluée par un test appelé « coreflood » qui est effectué dans des conditions (Pression et Température) très proches de celles du réservoir sur un échantillon de roche. La performance d’une expérimentation coreflood est évaluée par la détermination de la quantité d’huile récupérée et de la quantité de tensioactifs retenue sur la roche (par adsorption). Ces deux paramètres sont d’une importance primordiale pour confirmer la viabilité économique du procédé cEOR. Actuellement, les effluents de coreflood sont collectés dans des tubes tout au long de l'expérience et les analyses sont effectuées hors ligne. La quantité d'huile récupérée est mesurée par volumétrie (rapport eau/huile dans les tubes) ou par RMN. Les tensioactifs sont dosés dans la phase aqueuse par dosage à la hyamine ou par HPLC. Il est à noter que ces analyses peuvent être difficiles à effectuer expérimentalement car les effluents peuvent contenir des émulsions difficilement séparables. De plus, on ignore si tous les tensioactifs sont bien en phase aqueuse ou bien s’ils sont partiellement piégés dans la phase huileuse. Pour surmonter ces difficultés et quantifier les deux paramètres importants des expérimentations coreflood, nous avons développé une technique de mesure en ligne basée sur les outils microfluidiques. Le dispositif expérimental comprend : une puce de dilution pour transférer les tensioactifs dans la phase aqueuse, une chambre d’observation permettant de quantifier le ratio eau/huile des effluents par analyse d’images, un dispositif de séparation membranaire, et un spectromètre UV-visible en ligne pour le dosage des tensioactifs. Ce dispositif expérimental a été validé avec succès avec des mélanges de fluides modèles (décane, saumures de NaCl et dodécylbenzènesulfonate de sodium SDBS) et a été évalué sur des systèmes réels (pétrole brut et formulations de tensioactifs industriels). Finalement, il a été testé dans les conditions représentatives d’expérimentations coreflood, en étant directement connecté à la sortie d’une carotte de roche lors d’un tel essai. Les résultats obtenus pendant ces travaux de thèse ont prouvé l’efficacité du montage expérimental pour faciliter la quantification des tensioactifs, présents dans les effluents des expérimentations coreflood, et du volume d’huile récupéré. Ils ont montré une claire amélioration par rapport aux protocoles de quantification actuellement appliquésChemical Enhanced Oil Recovery (cEOR) is one of the methods used to meet the growing demand for oil. Among these methods we can find the surfactant flooding. Surfactant flooding consists in injecting an aqueous formulation, containing surfactants, in order to obtain ultra-low interfacial tensions (typically <10-2 mN / m) between water and oil and thus mobilize the oil trapped by capillary forces in the reservoir. Generally, a salinity-scan is performed, in the laboratory, to determine the optimal salinity (S*) of the formulation which corresponds to a minimum of interfacial tension. The optimal formulation is then evaluated through a "coreflood test" which is carried out on a rock sample under conditions (Pressure and Temperature) very close to those of the reservoir. The performance of a coreflood experiment is evaluated by determining the amount of oil recovered and the amount of surfactants retained in the reservoir (by adsorption). These two parameters are of prime importance to confirm the economic viability of the cEOR process. Currently, coreflood effluents are collected in tubes throughout the experiment and the analyses are performed offline. The quantity of oil recovered is measured by volumetry (water/oil ratio in the tubes) or RMN. Surfactants are dosed in the aqueous phase by hyamine assay or by HPLC. It is noteworthy that these analyses may be difficult to carry out experimentally since the effluents may contain emulsions that are difficult to separate. Moreover, it is unclear whether all surfactants are well in the aqueous phase, or whether they are partly trapped in the oil phase. To overcome these difficulties and quantify the two important parameters of coreflood experiments, we have developed an integrated online measurement technique based on microfluidic tools. The experimental setup includes: a dilution chip to transfer the surfactants in the aqueous phase, an observation chamber to quantify the water / oil ratio of the effluent by image analysis, a membrane-based separation device, and an on-line UV-visible spectrometer for surfactants quantification. This experimental setup was successfully validated with model fluid mixtures (decane, NaCl brines and sodium dodecyl benzene sulfonate SDBS), and was evaluated on real systems (crude oil and industrial surfactant formulations). Finally, it was tested under representative conditions of coreflood experiments, being directly connected to the output of a coreflood test. The results obtained during this thesis work proved the effectiveness of the experimental setup to facilitate the quantification of the surfactants in the effluents of the coreflood experiments, and the volume of oil recovered. They showed a clear improvement compared to the quantification protocols currently applied
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Bürk, Vincent [Verfasser], Eckhard [Gutachter] Weidner, and Marcus [Gutachter] Petermann. "Development of a measurement technique for the comparative study of non-Newtonian flow in porous media and its validation by measurements on different fluid systems related to Enhanced Oil Recovery / Vincent Bürk ; Gutachter: Eckhard Weidner, Marcus Petermann ; Fakultät für Maschinenbau." Bochum : Ruhr-Universität Bochum, 2021. http://d-nb.info/1226428711/34.
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Winjum, Olve. "Enhanced Measurements of Large Deformations of Thermoplastics." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for konstruksjonsteknikk, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-24511.
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The purpose of this study is to evaluate a numerical material model for thermoplastics developed at SIMLab, NTNU. Several experimental tests, using both HDPE and PVC, were conducted in order to have a basis for calibrating the material model. The focus of this thesis has been on optimizing the methods for retrieving the results of the experimental tests and numerical simulations.3D digital image correlation (DIC) was used to obtain the strains from the experimental tests. This proved very successful for the tension tests, but did not work well for longitudinal strains of the compression tests, which had to be calculated from the displacement. The 3D DIC analysis also allows for test specimens with circular cross sections to be used. These specimens proved to get better results than the quadratic specimens used in previous studies.Obtaining the strains from the numerical simulations was done by two different methods. One method was getting the strains directly from all the elements in one cross section; the other was calculating the strains from the displacement of the nodes on the surface of the specimen. This last method is equivalent to the DIC analysis, and resulted in a better match between the experimental and simulation results of the tension tests.The numerical model was largely able to reproduce the results of the experimental tests. The biggest problem seems to stem from the simulations having a higher strain rate than the experimental tests.
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Chen, Zhouye. "Reconstruction of enhanced ultrasound images from compressed measurements." Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30222/document.
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L'intérêt de l'échantillonnage compressé dans l'imagerie ultrasonore a été récemment évalué largement par plusieurs équipes de recherche. Suite aux différentes configurations d'application, il a été démontré que les données RF peuvent être reconstituées à partir d'un faible nombre de mesures et / ou en utilisant un nombre réduit d'émission d'impulsions ultrasonores. Selon le modèle de l'échantillonnage compressé, la résolution des images ultrasonores reconstruites à partir des mesures compressées dépend principalement de trois aspects: la configuration d'acquisition, c.à.d. l'incohérence de la matrice d'échantillonnage, la régularisation de l'image, c.à.d. l'a priori de parcimonie et la technique d'optimisation. Nous nous sommes concentrés principalement sur les deux derniers aspects dans cette thèse. Néanmoins, la résolution spatiale d'image RF, le contraste et le rapport signal sur bruit dépendent de la bande passante limitée du transducteur d'imagerie et du phénomène physique lié à la propagation des ondes ultrasonores. Pour surmonter ces limitations, plusieurs techniques de traitement d'image en fonction de déconvolution ont été proposées pour améliorer les images ultrasonores. Dans cette thèse, nous proposons d'abord un nouveau cadre de travail pour l'imagerie ultrasonore, nommé déconvolution compressée, pour combiner l'échantillonnage compressé et la déconvolution. Exploitant une formulation unifiée du modèle d'acquisition directe, combinant des projections aléatoires et une convolution 2D avec une réponse impulsionnelle spatialement invariante, l'avantage de ce cadre de travail est la réduction du volume de données et l'amélioration de la qualité de l'image. Une méthode d'optimisation basée sur l'algorithme des directions alternées est ensuite proposée pour inverser le modèle linéaire, en incluant deux termes de régularisation exprimant la parcimonie des images RF dans une base donnée et l'hypothèse statistique gaussienne généralisée sur les fonctions de réflectivité des tissus. Nous améliorons les résultats ensuite par la méthode basée sur l'algorithme des directions simultanées. Les deux algorithmes sont évalués sur des données simulées et des données in vivo. Avec les techniques de régularisation, une nouvelle approche basée sur la minimisation alternée est finalement développée pour estimer conjointement les fonctions de réflectivité des tissus et la réponse impulsionnelle. Une investigation préliminaire est effectuée sur des données simuléesThe interest of compressive sampling in ultrasound imaging has been recently extensively evaluated by several research teams. Following the different application setups, it has been shown that the RF data may be reconstructed from a small number of measurements and/or using a reduced number of ultrasound pulse emissions. According to the model of compressive sampling, the resolution of reconstructed ultrasound images from compressed measurements mainly depends on three aspects: the acquisition setup, i.e. the incoherence of the sampling matrix, the image regularization, i.e. the sparsity prior, and the optimization technique. We mainly focused on the last two aspects in this thesis. Nevertheless, RF image spatial resolution, contrast and signal to noise ratio are affected by the limited bandwidth of the imaging transducer and the physical phenomenon related to Ultrasound wave propagation. To overcome these limitations, several deconvolution-based image processing techniques have been proposed to enhance the ultrasound images. In this thesis, we first propose a novel framework for Ultrasound imaging, named compressive deconvolution, to combine the compressive sampling and deconvolution. Exploiting an unified formulation of the direct acquisition model, combining random projections and 2D convolution with a spatially invariant point spread function, the benefit of this framework is the joint data volume reduction and image quality improvement. An optimization method based on the Alternating Direction Method of Multipliers is then proposed to invert the linear model, including two regularization terms expressing the sparsity of the RF images in a given basis and the generalized Gaussian statistical assumption on tissue reflectivity functions. It is improved afterwards by the method based on the Simultaneous Direction Method of Multipliers. Both algorithms are evaluated on simulated and in vivo data. With regularization techniques, a novel approach based on Alternating Minimization is finally developed to jointly estimate the tissue reflectivity function and the point spread function. A preliminary investigation is made on simulated data
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Esch, Hendrik [Verfasser], Reiner [Akademischer Betreuer] Klingenberg, and Wolfgang [Gutachter] Wagner. "Measurement of the top quark mass in topologies enhanced with single top quarks produced in the t-channel using flavour tagging and a neural network with ATLAS data at √s = 8TeV / Hendrik Esch. Betreuer: Reiner Klingenberg. Gutachter: Wolfgang Wagner." Dortmund : Universitätsbibliothek Dortmund, 2015. http://d-nb.info/1101476516/34.
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Sabines, Chesterking Javier. "Overcoming practical limitations to realise photonic quantum-enhanced measurements." Thesis, University of Bristol, 2018. http://hdl.handle.net/1983/45e87843-75a2-43b6-ba3f-0f38ade5e623.
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In theory, quantum states of lights can be used to perform measurements with a level of precision beyond that which can be attained with their classical counterparts. In practice,they can only do so when the components that we use to generate, manipulate and measure them, operate beyond specific thresholds. In this thesis, we seek to address different obstacles that hinder our ability to fully exploit quantum-metrological schemes. We mainly focus our attention in quantum-enhanced optical transmission measurements. For this we make use of photon pair sources and take advantage of the photon number correlations of the sources to suppress noise in parameter estimation. With this approach we are able to reach a level of precision beyond the shot-noise limit without the use of post-selection. We achieve this by implementing feed-forward and using a CCD camera with high detection efficiency. We have been able to obtain measurements of transmission with a maximum factor of advantage of 1.66 when compered to an ideal classical experiment using a noiseless coherent source and a 100% efficient detector. We have also studied the roll of photon distinguishability in quantum-enhanced phase estimation, where we have performed experiments with two and four-photons states controlling their level of distinguishability and we demonstrate that fully indistinguishable photons are not required to obtain quantum-enhanced measurements.
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Zebrowski, David Stephen. "Condensation heat-transfer measurements of refrigerants on externally enhanced tubes." Thesis, Monterey, California. Naval Postgraduate School, 1987. http://hdl.handle.net/10945/22222.
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Pasha, Hasan G. "Estimation of Static Stiffnesses from Free Boundary Dynamic (FRF) Measurements." University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1416569956.
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Silander, Isak. "Cavity enhanced optical sensing." Doctoral thesis, Umeå universitet, Institutionen för fysik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-110278.
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An optical cavity comprises a set of mirrors between which light can be reflected a number of times. The selectivity and stability of optical cavities make them extremely useful as frequency references or discriminators. With light coupled into the cavity, a sample placed inside a cavity will experience a significantly increased interaction length. Hence, they can be used also as amplifiers for sensing purposes. In the field of laser spectroscopy, some of the most sensitive techniques are therefore built upon optical cavities. In this work optical cavities are used to measure properties of gas samples, i.e. absorption, dispersion, and refractivity, with unprecedented precision. The most sensitive detection technique of all, Doppler-broadened noise-immune cavity enhanced optical heterodyne molecular spectrometry (Db NICE-OHMS), has in this work been developed to an ultra-sensitive spectroscopic technique with unprecedented detection sensitivity. By identifying limiting factors, realizing new experimental setups, and determining optimal detection conditions, the sensitivity of the technique has been improved several orders of magnitude, from 8 × 10-11 to 9 × 10-14 cm-1. The pressure interval in which NICE-OHMS can be applied has been extended by derivation and verification of dispersions equations for so-called Dicke narrowing and speed dependent broadening effects. The theoretical description of NICE-OHMS has been expanded through the development of a formalism that can be applied to the situations when the cavity absorption cannot be considered to be small, which has expanded the dynamic range of the technique. In order to enable analysis of a large number of molecules at their most sensitive transitions (mainly their fundamental CH vibrational transitions) NICE-OHMS instrumentation has also been developed for measurements in the mid-infrared (MIR) region. While it has been difficult to realize this in the past due to a lack of optical modulators in the MIR range, the system has been based on an optical parametric oscillator, which can be modulated in the near-infrared (NIR) range. As the index of refraction can be related to density, it is possible to retrieve gas density from measurements of the index of refraction. Two such instrumentations have been realized. The first one is based on a laser locked to a measurement cavity whose frequency is measured by compassion with an optical frequency comb. The second one is based on two lasers locked to a dual-cavity (i.e. one reference and one measurement cavity). By these methods changes in gas density down to 1 × 10-9 kg/m3 can be detected. All instrumentations presented in this work have pushed forward the limits of what previously has been considered measurable. The knowledge acquired will be of great use for future ultrasensitive cavity-based detection methods.
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Capobianco, Ryan Michael. "Ionization in H2O -- bearing carbon dioxide determined by conductivity measurements." Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/23283.
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Recent studies report rapid corrosion of metals and carbonation of minerals in contact with H2O-saturated (or nearly saturated) CO2. One explanation for this behavior is that addition of small amounts of H2O to CO2 leads to significant ionization within the fluid (analogous to corrosion in aqueous fluids). The extent of ionization in the bulk CO2 fluid was determined using a flow-through conductivity cell capable of analyzing very dilute solutions. Experiments were conducted from 25 to 200"C and 25 to 200 bar with H2O concentrations up to ~1650 ppmw. In all experiments, conductivities <10 nS/cm were obtained, indicating that the solution is essentially ion-free. This observation suggests that mobile ions are not present in the bulk CO2--rich fluid, and that the observed corrosion and carbonation reactions are not the result of ionization in the bulk fluid.Master of Science
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Sutton, C. P. "Application of surface enhanced raman spectroscopy to measurements of diffusion through silastic membranes." Thesis, University of Kent, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342271.
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Adams, Thomas John. "Atmospheric measurements of biogenic and anthropogenic emissions by broadband cavity enhanced absorption spectroscopy." Thesis, University of Leicester, 2016. http://hdl.handle.net/2381/37611.
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This thesis describes the quantification of biogenic and anthropogenic trace gases using the highly sensitive spectroscopic technique of broadband cavity enhanced absorption spectroscopy (BBCEAS). This technique uses a high finesse optical cavity to make absorption measurements over extended path lengths within a compact instrument and over wavelength ranges that are sufficiently broad to enable several overlapping absorbers to be quantified simultaneously. Here, BBCEAS was applied to measure I₂ emissions in coastal regions, NO₂ in urban ambient air, and VOC oxidation products during experiments in an atmospheric simulation chamber. Much of the work used a novel, mobile, battery-powered BBCEAS system to measure gas concentrations in very close proximity to their emission sources. The dominant emission source of iodine into the atmosphere in coastal regions comes from intertidal macroalgal beds. Gas-phase iodine chemistry perturbs the HOₓ and NOₓ radical cycles, provides additional sink reactions for tropospheric ozone, and initiates nucleation of new aerosol particles. Results are presented from an extensive laboratory study of I₂ emissions from five species of temperate seaweeds. Time- and species-dependent I₂ emission rates were quantified in studies mimicking the progressive exposure of seaweeds to air around low tide. Seasonal differences in I₂ emission rates were investigated. By deploying the BBCEAS instrument from a boat, I₂ concentrations were also measured directly above Laminaria digitata and Ascophyllum nodosum seaweeds growing in their natural habitat. NOₓ emissions affect urban air quality directly and indirectly (the latter via formation of tropospheric ozone and secondary aerosol). BBCEAS was applied to measure NO₂ and the optical extinction from aerosol particles at locations around the Leicester University campus. BBCEAS results were compared with commercial NOₓ (chemiluminescence) and aerosol instrumentation. The mobile BBCEAS instrument was also deployed to investigate the dispersion of NO₂ from the roadside.
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Kong, Jonathan Hein Khuen. "Improving Radiological Measurements to Enhance the Conservative Management of Vestibular Schwannomas." Thesis, The University of Sydney, 2015. http://hdl.handle.net/2123/15702.
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Background Vestibular Schwannoma management has changed significantly over the last few decades, with a trend to conservative management, at least initially. A major factor in discontinuing conservative management is evidence of tumour growth. Maximum linear diameter measurement is convenient, but highly variable. Volumetric measurements are considered more representative, but vary widely with current techniques, are time-consuming, and often require expensive radiological hardware and software. A superior measurement method is required. Methods MRI Scans for 121 vestibular schwannoma patients were exported as DICOM images and analysed. Scans were included if the tumour was at least partially in the cerebello-pontine angle. Exclusion criteria included: absence of a thin section high resolution T2 axial sequence (1mm or thinner), poor quality scans, neurofibromatosis type 2, or scans suggestive of another diagnosis. There were 56 scans remaining. A new volume measurement system was constructed including a laptop computer, a pen graphics tablet, and Osirix software. Volumetric calculations by tracing the tumour on MRI were performed on all 56 scans by both a specialist neuro-radiologist and an otologist/skull base surgeon, each twice, on separate occasions, in a double-blinded fashion. The volumetric measurements were analysed for both intra-observer and inter-observer variability, and time taken to perform the measurements noted. Linear measurements were taken for comparison with the literature. Results Both intra-observer and inter-observer variability showed excellent agreement. Time for volumetric measures to be obtained ranged from 1-3 minutes per tumour. Detailed statistical analysis ensued. Conclusions This technique is feasible, accurate, and precise. The measurements are relatively quick, and practical for daily clinical use. This can accurately detect tumour growth, and provides a potential for standardising tumour size reporting.
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Erdogan, Levent. "Suspension Parameter Measurement Using Side-Pull Test to Enhance Modeling of Vehicle Roll." The Ohio State University, 1999. http://rave.ohiolink.edu/etdc/view?acc_num=osu1392212782.
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Funk, Samuel Mahlon. "Efficiency and productivity measurements to analyze farm-level impacts from adoption of biotechnology enhanced soybeans." Diss., Kansas State University, 2015. http://hdl.handle.net/2097/20563.
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Doctor of PhilosophyDepartment of Agricultural Economics
Allen M. Featherstone
This study focuses on the productivity and on-farm efficiency impacts of adopting biotechnology enhanced soybeans (BES). Previous research suggests the adoption of BES and subsequent time savings resulted in labor allocation to off-farm employment and reduced on-farm efficiency. Using continuous panel data for 129 farms enrolled in the Kansas Farm Management Association (KFMA) with production and financial crop records from 1993 through 2011 that also provided information on their BES adoption experience, this study provides estimates on the technical efficiency, cost efficiency, and Malmquist productivity indexes (MI) with decompositions into efficiency change (EC) and technical change (TC) to provide insights on the impacts of adopting BES for set of sample farms. Using data envelopment analysis to construct nonparametric efficiency frontiers and measurements assuming constant returns-to-scale (CRS) and variable returns-to-scale (VRS) technologies for the farms, this study provides insights on the impact of yield impacts of BES adoption. A biennial Malmquist productivity index (BMI) is developed to consider estimation of the productivity impacts between BES adopters and non-adopters assuming VRS. This analysis used five input categories: Labor, general, direct inputs, maintenance, and energy; and five outputs: corn, soybeans, sorghum, wheat, and other crops. Tobit regression analysis of the panel of Kansas farms provided evidence of a positive impact from adoption of biotechnology enhanced soybeans on on-farm technical efficiency. Kolmogorov-Smirnov goodness-of-fit distributional hypothesis tests showed significant differences between analyzing the farms under CRS and VRS assumptions. T-tests showed a bias existed when assuming CRS if the true underlying technology was VRS in productivity analysis. However, there was not a strong statistically significant difference between the distributions of productivity measures from the underlying populations of BES adopters and non-adopters in the sample of Kansas farms. A revenue-indirect cost efficiency analysis of the sample farms demonstrated that different conclusions were reached under CRS and VRS when considering the differences in the average of the means of estimated efficiency scores and Tobit regression results considering BES adoption. Assuming CRS resulted in positive marginal effects for adopting BES of 0.017 significant at the 5% level. The marginal effect of BES adoption was not statistically significant under VRS.
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Tang, Huiling. "Rheological Measurements and Core Flood Data Analysis in Support of Chemical Enhanced Oil Recovery Formulation Design." Thesis, Purdue University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10618534.
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This research involved rheological measurements and the analysis of core flood test data in support of the design of a formulation for Chemical Enhanced Oil Recovery (cEOR) at the Pioneer Rock Hill reservoir, a site characterized by relatively low formation brine salinity and temperature. Extensive and systematic rheological measurements identified viscosity values and rheological behaviors of different polymers, surfactants and polymer-surfactant solutions over a range of concentrations, salinities, and temperatures relevant to the targeted field conditions. The results were used to support formulation design in combination with phase behavior studies and interfacial tension measurements, provide information relevant to in-tank mixing/pumping operations, and maximize sweep efficiency and mobility control in the core flood tests. Further rheological measurements were conducted on the primary surfactant, Petrostep® S13D, over a broad range of concentrations in both deionized water and two synthetic brines, up to neat solution. The results of these tests indicate that different structures (micellar solution, hexagonal liquid crystal, and lamellar liquid crystal) form at different concentrations, supporting SAXS observations performed by another research group.
In a separate effort, data obtained from core flood tests conducted in the Purdue EOR laboratory to evaluate and optimize formulations, were collected and organized. Five performance parameters: recovery factor in terms of %ROIP, oil saturation after chemical flood (Sorc), maximum injection pressure during chemical flood, surfactant sorption, and total injectant cost, were selected to evaluate test efficiency, based on technical and economic feasibility. Performance analysis of the core flood data and comparison with data from the literature show average to very good performance of the Purdue core flood tests.
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Endrass, Ferdinand. "Performance measurement using shop floor data : Integrating information to enhance performance of manufacturing operations management." Thesis, KTH, Industriell produktion, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-134349.
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Networking machinery enables companies to easily retrieve information from modern production systems. Still, a lot of information remains unused. This results in performance gaps, since not all relevant information is taken into consideration when making decisions in the context of operational management. Users regard information as valuable as soon as it supports the achievement of a production objective. Therefore, the linkage between the origin of information and the user becomes important. Integrating information in a comprehensive and effective way contributes to a performance improvement of a production system. At the same time as more information is available, performance measures, which are a tool to improve performance when applied correctly, have received a lot of attention in research. However, the applicability of performance measures based on shop floor data remains a challenging task. Due to that, this thesis intends to close performance gaps by the means of performance measures which are based on shop floor data. In the beginning of this work, the sources of information as well as users and their objectives are identified. Additionally, existing performance measures and frameworks are reviewed. A four-stage based approach for the introduction of a measurement framework focussing on the utilization of shop floor data is developed. This approach is accompanied by a tool, which facilitates the development process of performance measures and establishes a link between users and the sources of information. In the last part of this thesis, the approach and tool are tested in an industrial environment.
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Godavarty, Anuradha. "Fluorescence enhanced optical tomography on breast phantoms with measurements using a gain modulated intensified CCD imaging system." Texas A&M University, 2003. http://hdl.handle.net/1969.1/2184.
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Fluorescence-enhanced optical imaging using near-infrared (NIR) light developed for in-vivo molecular targeting and reporting of cancer provides promising opportunities for diagnostic imaging. However, prior to the administration of unproven contrast agents, the benefits of fluorescence-enhanced optical imaging must be assessed in feasibility phantom studies.
A novel intensified charge-coupled device (ICCD) imaging system has been developed to perform 3-D fluorescence tomographic imaging in the frequency-domain using near-infrared contrast agents. This study is unique since it (i) employs a large tissue-mimicking phantom (~1087 cc), which is shaped and sized to resemble a female breast and part of the extended chest wall region, and (ii) enables rapid data acquisition in the frequency-domain by using a gain-modulated ICCD camera. Diagnostic 3-D fluorescence-enhanced optical tomography is demonstrated using 0.5-1 cc single and multiple targets contrasted from their surrounding by ??M concentrations of Indocyanine green (ICG) in the breast-shaped phantom (10 cm diameter), under varying conditions of target-to-background absorption contrast ratios (1:0 and 100:1) and target depths (up to 3 cm deep). Boundary surface fluorescence measurements of referenced amplitude and phase shift were used along with the coupled diffusion equation of light propagation in order to perform 3-D image reconstructions using the approximate extended Kalman filter (AEKF) algorithm, and hence differentiate the target from the background based on fluorescent optical contrast.
Detection of single and multiple targets is demonstrated under various conditions of target depths (up to 2 cm deep), absorption optical contrast ratio (1:0 and 100:1), target volumes (0.5-1 cc), and multiple targets (up to three 0.5 cc targets). The feasibility of 3-D image reconstructions from simultaneous multiple point excitation sources are presented. Preliminary lifetime imaging studies with 1:2 and 2:1 optical contrast in fluorescence lifetime of the contrast agents is also demonstrated. The specificity of the optical imager is further assessed from homogeneous phantom studies containing no fluorescently contrasted targets.
While nuclear imaging currently provides clinical diagnostic opportunities using radioactive tracers, molecular targeting of tumors using non-ionizing NIR contrast agents tomographically imaged using the frequency-domain ICCD imaging system could possibly become a new method of diagnostic imaging.
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Kennedy, Oliver John. "Development and deployment of a broadband cavity enhanced absorption spectroscopy instrument for airborne measurements of trace gases." Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610332.
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Olsson, Sven. "Signal processing as a tool to enhance productivity in industry : measurement and cancelation of periodic signals /." Karlskrona : Blekinge Institute of Technology, 2006. http://www.bth.se/fou/Forskinfo.nsf/allfirst2/943903fa5c44972dc1257133002f9177?OpenDocument.
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Vabbilisetty, Pratima. "Fabrication and Characterization of Substrate Materials for Trace Analytical Measurements by Surface Enhanced Raman Scattering (SERS) Spectroscopy Technique." Connect to resource online, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1231794465.
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Alves, Montanari Allan. "Enhanced instantaneous power theory for control of grid connected voltage sourced converters under unbalanced conditions." IEEE Transactions on Power Electronics, 2017. http://hdl.handle.net/1993/32184.
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This thesis introduces a new method especially designed to control the instantaneous power in voltage sourced converters operating under unbalanced conditions, including positive, negative and zero sequence content. A transformation technique, labelled mno transformation, was developed to enable the decomposition of the total instantaneous power flowing on three-phase transmission topologies into constant and oscillating terms. It is applied to three-wire and four-wire schemes, especially accommodating zero sequence unlike previous approaches. Classical and modern electric power theories are presented, particularly focusing on their definitions for adverse AC scenarios. The main mathematical transformations conceived to analyze such situations are summarized, showing their respective advantages and disadvantages. An enhanced instantaneous power theory is introduced. The novel proposed power equations, named mno instantaneous power components, expands the application of the p-q theory, which is attached to the αβ0 transformation. The mno instantaneous power theory is applied to develop an innovative power control method for grid connected voltage sourced converters in order to minimize power oscillations during adverse AC scenarios, particularly with zero sequence content. The method permits to sustain constant instantaneous three-phase power during unbalanced conditions by controlling independently the constant and the oscillating terms related to the instantaneous power. The effectiveness of the proposed control approach and the proposed power conditioning scheme was demonstrated using electromagnetic transient simulation of a VSC connected to an AC system.May 2017
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Franks, James R. "The development and implementation of variable tip-sample separation scanning tunnelling spectroscopy to enhance spectroscopic measurements." Thesis, Swansea University, 2003. https://cronfa.swan.ac.uk/Record/cronfa42341.
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Scanning Tunnelling Microscopy (STM) and Spectroscopy (STS) are valuable surface science techniques in the characterisation of a wide variety of surfaces on the atomic scale. When STM and STS are performed concurrently, both the topological and electronic properties of a surface can be investigated. Conventionally STS is performed with the tip-sample separation fixed, which leads to a limited dynamic range in the measurement. This limitation can be overcome by varying the tip-sample separation during STS. Varying the tip-sample separation improves the dynamic range by exploiting the exponential relationship between tunnel current and tip-sample separation. To accomplish variable tip-sample separation STS with Omicron Micro STM and STM/SEM-HC Scanning Tunnelling Microscope systems, external instrumentation was designed and fabricated. This instrumentation operated in conjunction with the Omicron microscopes to create the tip-sample contour and measure conductivity during variable tip-sample separation STS. The instrumentation performed as expected, although problems were encountered making conductivity measurements using a Lock-in amplifier. Conductivity spectra obtained using a Lock-in amplifier contained perturbations related to the tip-sample capacitance. Future work is required to compensate for the effects of the tip-sample capacitance in conductivity measurements based around a Lock-in amplifier. To comparatively evaluate variable and fixed tip-sample separation techniques, STS was performed consecutively on Si(111) 7x7 and GaAs(110) surfaces. For both surfaces an improvement in the definition of spectral features is observed. In the case of GaAs(110), surface states indistinguishable from noise in fixed tip-sample separation STS are clearly observed utilising variable tip-sample separation.
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Cinca, Diane. "Etude de la production de paires de quarks TOP avec ATLAS au LHC, mesure de la masse du quark TOP." Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2011. http://tel.archives-ouvertes.fr/tel-00653792.
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Découvert en 1995 à Fermilab, le quark top est le dernier quark découvert. La mesure de ses propriétés permet de tester les prédictions du Modèle Standard et de contraindre la masse du boson de Higgs. De par ses propriétés, le quark top est aussi un partenaire privilégié dans la recherche de particules de Nouvelle Physique attendues à l'échelle du TeV. Ce travail de thèse, effectué auprès du détecteur ATLAS au LHC, présente les méthodes mises en oeuvre afin de mesurer la masse du quark top dans sa désintégration semileptonique. Différentes méthodes de reconstruction des évènements top sont présentées ainsi qu'une analyse dédiée basée sur les arbres de décision boostés. Ses performances sont quantifiées. La mesure précise de la masse du quark top nécessite une compréhension approfondie de l'échelle en énergie des jets. Deux stratégies sont présentées afin de calibrer les jets légers et les jets issus de quark b à l'échelle partonique. Les performances d'un ajustement cinématique appliqué à la mesure de la masse du quark top sont présentées. Une mesure de la masse du quark top est extraite en utilisant une définition de la masse calibrée à l'échelle partonique.