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1
Hauerstock, David. "Telemetric measurement of compressive loads in the sheep lumbar spine". Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=30785.
Testo completoAbstract (sommario):
The goal of this study was to develop and validate a system for the telemetric measurement of in vivo compressive intervertebral loads in the sheep, and to measure these loads in a variety of activities.A miniature load cell and radio transmitter were implanted in the L3--L4 space of the spine. A total of four sheep were operated on; one was sacrificed five days after surgery, due to failure of the transmitter, and another was sacrificed after failing to ambulate for two weeks after surgery. The other two animals (average mass 67 kg) were kept for five weeks, during which a range of activities were performed, including standing, lying prone, walking/trotting, and jumping.
Results for a range of activities were as follows: in walking at 1.5 m/s, average maximum and minimum loads were 461 N and 256 N, respectively; in walking at 2m/s, average maximum and minimum loads were 684 N and 303 N, respectively; in standing, loads averaged 161 N; and in lying prone, loads averaged 212 N. The highest loads were recorded in jumping, where the peak load was 1290 N.
The results of this study demonstrate for the first time, to our knowledge, the magnitude of in vivo axial loads in the sheep lumbar spine. These findings have implications for the evaluation of studies which employ the sheep model to test spinal implants. As treatment methods for disc degeneration progress from the spacer and fusion approach to more sophisticated prostheses and tissue engineered disc replacements which preserve segmental mobility, such data will become even more important to the design, animal testing, and evaluation of implants.
2
Zheng, Yalin. "Automated segmentation of lumbar vertebrae for the measurement of spine kinematics". Thesis, University of Southampton, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.288154.
Testo completo
3
Hindle, Richard John. "Three-dimensional kinematics of the human back in the normal and pathologic spine". Thesis, Durham University, 1989. http://etheses.dur.ac.uk/6513/.
Testo completoAbstract (sommario):
This thesis investigated the relationship between the three-dimensional kinematics of the human back and spinal pathology. This required the development of a system capable of the in vivo measurement of spinal movement non-invasively and in three-dimensions. The opto-electronic CODA-3 Scanner proved unsatisfactory in this respect. The electro-magnetic 3SPACE Isotrak, however, was found to be an accurate and reliable system during a study of twisting in flexed postures. Available axial rotation was significantly increased in some degree of sagittal flexion suggesting that this may be a mechanism for intervertebral disc injury. At high degrees of sagittal flexion a reduction in available axial rotation was noted. In vitro tests on isolated lumbar motion segments confirmed the increase in axial rotation available in flexed postures shown in vivo, this was presumed to be due to an opening of the lumbar zygapophysial joints. Mechanical testing of lumbar interspinous and supraspinous ligaments showed them to be active only in the extremes of sagittal flexion and hence that they could be responsible for the reduction in axial rotation seen in vivo. The 3SPACE Isotrak was used in a clinical study of 80 normal and 43 pathologic subjects. In the normals ranges of motion were, in general, reduced with increasing age in both males and females although a significant increase in sagittal flexion occurred with increasing age in females. Male mobility significantly exceeded female in sagittal flexion but female tended to exceed male in extension, lateral bend and axial rotation. Opposite axial rotation occurred consistently upon lateral bend and vice versa, flexion also occurred on lateral bend but not axial rotation. There was widespread disruption to the primary and coupled movements of the back pain patients when compared to normal movement patterns but there was no clear distinction between the kinematic movement patterns of discrete patient groups. The small numbers in these patient groups warrant a further, more detailed, clinical study.
4
Harvey, Steven Brian. "Interactive computer methods for morphometric and kinematic measurement of images of the spine". Thesis, University of Aberdeen, 1999. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU116153.
Testo completoAbstract (sommario):
The aim of this project was to develop robust interactive computer methods for measuring the shape and movement of the lumbar spine vertebrae from lateral radiographs of the spine. In order to achieve this aim, two software packages were written - the Aberdeen Vertebral Morphometry System (AVMS) and the Aberdeen Spinal Videofluoroscopy System (ASVS). AVMS was designed to analyse static images from dual energy x-ray absorptiometry (DXA) imaging densitometers. Comparative precision tests of the ability of AVMS software and Lunar EXPERT-XL software to measure vertebral height were undertaken using four vertebrae from the same lateral spine image (male, 67 years). Two of the vertebrae in this image were abnormal and two were normal. It was concluded that AVMS had higher precision when measuring abnormal and normal vertebrae. The effects of axial rotation and lateral bending, which lead to movement out of the sagittal plane, were investigated by generating a three-dimensional computer model of two adjacent vertebrae and projecting it on to the sagittal plane. The projected model was measured as if it were a radiograph, allowing the effects of out-of-plane movement and errors in reference point placement to be calculated. ASVS was used to acquire and analyse a sequence of images of the spine in motion obtained using videofluoroscopy and incorporated the findings of the computer modelling work. A clinical study for the measurement of intervertebral motion using ASVS during flexion-extension was organised and seven subjects suffering from severe lower back pain were recruited. Analysis of the image sequences using the computerised measurement system in ASVS revealed the apparent effect of analgesia/sedative on the shape and size of centroidal trajectories of vertebrae, and the differences in trajectory shape between subjects. It was concluded that ASVS was able to quantify spinal motion at a minimal radiation dose to the subject.
5
Breen, Alan Clark. "The measurement of the kinematics of the human spine using videofluoroscopy and image processing". Thesis, University of Southampton, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303090.
Testo completo
6
Darlington, Sarah Elizabeth. "Effect of intra-abdominal fat on the accuracy of DXA lumbar spine bone mineral density measurement using DXA body composition measurements". Thesis, Cardiff University, 2012. http://orca.cf.ac.uk/44881/.
Testo completoAbstract (sommario):
In the diagnosis of osteoporosis, dual-energy X-ray absorptiometry (DXA) is the accepted method for measuring bone mineral density (BMD) due to its good precision. However, accuracy is compromised by two assumptions: (1) the body is composed of only soft tissue and bone mineral and (2) the composition of tissue overlying bone is equal to that adjacent to bone. To diagnosis osteoporosis, BMD is compared to that of a young healthy population to calculate a T-score. BMD is normal if T-score>-1 and osteoporotic if < -2.5. The aim of this study was to use DXA whole body (WB) scans to quantify variation in abdominal fat thickness and to explore whether this information could be used to improve the accuracy of lumbar spine (LS) BMD measurement. Relevant data were extracted from archived DXA images for groups of patients who had received both LS and WB scans. LS BMD increased with the width of the associated soft tissue baseline and BMD was correlated with fat thickness within the baseline. For individuals, the bone mineral equivalence of the difference in fat thickness between a standard width baseline and a region over the spine corresponded to a maximum T-score difference of 0.6. However, the average for the groups gave a T-score difference of 0.2. The predicted inaccuracy in LS BMD measurement resulting from a non-uniform fat distribution was within 0.013 g/cm2 for groups and 0.017 g/cm2 for individuals. From these measurements, errors in BMD of up to 6% and 3% for a standard width baseline were observed for individuals and groups respectively. In the majority of patients, errors introduced by a non-uniform distribution of fat are unlikely to cause a mis-diagnosis. However, significant errors may occur in certain individuals. The clinical application of the proposed method to quantify errors in BMD requires further investigation
7
Beange, Kristen. "Validation of Wearable Sensor Performance and Placement for the Evaluation of Spine Movement Quality". Thesis, Université d'Ottawa / University of Ottawa, 2019. http://hdl.handle.net/10393/38698.
Testo completoAbstract (sommario):
Inertial measurement units (IMUs) are being recognized as a portable and cost-effective alternative to motion analysis systems and have the potential to be introduced into clinical settings for the assessment of functional movement quality of the spine in patients with low back pain. However, uncertainties regarding sensor accuracy and reliability are limiting the widespread use and acceptance of IMU-based assessments into routine clinical practice. The objective of this work was to assess the performance of inexpensive wearable IMUs (Mbientlab MetaMotionR IMUs; Mbientlab Inc., San Francisco, USA; product specifications available in Appendix C) relative to conventional optical motion capture equipment (Vicon Motion Systems Ltd., Oxford, UK) in: 1) a controlled environment, and 2) an uncontrolled environment.
The first study evaluated the performance of 2 IMUs in a controlled environment during simulated repetitive spine motion carried out by means of a motorized gimbal. Root mean square error (RMSE) and mean absolute measurement differences between cycle-to-cycle minimum, maximum, and range of motion values, as well as correlational analyses within IMUs and between IMUs and Vicon, in all movement directions (i.e., simulated flexion-extension (FE), lateral bending (LB), and axial twisting (AT)), were compared. Measurement error was low in all axes during all tests (i.e., ≤ 1.54°); however, low-to-moderate correlational results were found in one non-primary axis, and this axis changed depending on the direction of the movement (i.e., LB during FE-motion (0.244 ≤ R ≤ 0.515), AT during LB-motion (0.594 ≤ R ≤ 0.795), and FE during AT-motion (0.002 ≤ R ≤ 0.255)).
The second study was designed to assess the performance of the IMUs in an uncontrolled environment during repetitive spine FE in human participants. Absolute angles and local dynamic stability were compared for individual IMUs (which were placed over T10-T12 spinous processes, and the pelvis) as well as for relative motion between IMUs. Maximum finite-time Lyapunov exponents (λmax) were used to quantify local dynamic stability and were calculated using both FE and the sum of squares (SS) from measured spine kinematics. It was found that the IMUs have acceptable performance in all axes when tracking motion (RMSE ≤ 2.43°); however, low-to-moderate correlational results were found in one non-primary axis (0.987 ≤ RFE ≤ 0.998; 0.746 ≤ RLB ≤ 0.978; 0.343 ≤ RAT ≤ 0.679). In addition, correlations between λmax estimates were high; therefore, local dynamic stability can be accurately estimated using both FE and SS data (0.807 ≤ 〖ICC〗_2,1^FE ≤ 0.919; 0.738 ≤ 〖ICC〗_2,1^SS ≤ 0.868). Correlation between λmax estimates was higher when using FE data for individual sensors/rigid-body marker clusters; however, correlation was higher when using SS data for relative motion.
In general, the results of these studies show that the MetaMotionR IMUs have acceptable performance in all axes when considering absolute angle orientation and motion tracking, and measurement of local dynamic stability; however, there is low-to-moderate correlation in one non-primary axis, and that axis changes depending on the direction of motion. Future research will investigate how to optimize performance of the third axis for motion tracking; it will also focus on understanding the significance of the third axis performance when calculating specific outcome measures related to spine movement quality.
8
MacMillan, Erin Leigh. "Myelin water measurement by magnetic resonance imaging in the healthy human spinal cord : reproducibility and changes with age". Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/1887.
Testo completoAbstract (sommario):
Multi-echo T2 relaxation measurements of the human spinal cord (SC) reveal a short T2 pool of water believed to arise from water trapped between myelin bilayers, where the proportion of this water to the total water signal is called the myelin water fraction (MWF). In the present study, MWF were measured in the healthy human cervical spine at the C4-C6 vertebral levels in vivo using a 3D modified 32 echo CPMG sequence to acquire axial slices perpendicular to the cord. Volunteers were recruited in two age ranges, under 30 years old and over 50 years old, and a subset of both groups were scanned twice to test reproducibility. Mean MWF in the dorsal and lateral column WM of the group under 30 years of age was 0.29 (0.01) (mean(SE)), which agrees with previously reported MWF values in the cervical spine. The mean absolute difference between two scans was 0.06 or 26%. A negative correlation between WM MWF and age was hinted at in these findings, however more subjects are required to improve statistical power. This study paves the way for the use of 3D myelin water imaging in the cervical spine at 3.0T for the assessment of SC WM pathology.
9
Toosizadeh, Nima. "Time-dependent assessment of the human lumbar spine in response to flexion exposures: in vivo measurement and modeling". Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/19274.
Testo completoAbstract (sommario):
Among several work-related injuries, low back disorders (LBDs) are the leading cause of lost workdays, and with annual treatment costs in excess of $10 billion in the US. Epidemiological evidence has indicated that prolonged and/or repetitive non-neutral postures, such as trunk flexion, are commonly associated with an increased risk of LBDs. Trunk flexion can result in viscoelastic deformations of soft tissues and subsequent mechanical and neuromuscular alterations of the trunk, and may thereby increase LBD risk. While viscoelastic behaviors of isolated spinal motion segments and muscles have been extensively investigated, in vivo viscoelastic responses of the trunk have not, particularly in response to flexion exposures. Further, most biomechanical efforts at understanding occupational LBDS have not considered the influence of flexion exposures on spine loads.
Four studies were completed to characterize viscoelastic deformation of the trunk in response several flexion exposures and to develop and evaluate a computational model of the human trunk that accounts for time-dependent characteristics of soft tissues. Participants were exposed to prolonged flexion at different trunk angles and external moments, and repetitive trunk flexion with different external moments and flexion rates. Viscoelastic properties were quantified using laboratory experiments and viscoelastic models. A multi-segment model of the upper body was developed and evaluated, and then used to estimate muscle forces and spine loads during simulated lifting tasks before and after prolonged trunk flexion at a constant angle and constant external moment. Material properties from the earlier experiments were used to evaluate/calibrate the model.
Experimental results indicated important effects of flexion angle, external moment, and flexion rate on trunk viscoelastic behaviors. Material properties from fitted Kelvin-solid models differed with flexion angle and external moment. Nonlinear viscoelastic behavior of the trunk tissues was evident, and predictive performance was enhanced using Kelvin-solid models with ≥2 iii retardation/relaxation time constants. Predictions using the multi-segment model suggested increases in spine loads following prolonged flexion exposures, primarily as a consequence of additional muscle activity. As a whole, these results help to characterize the effects of trunk flexion exposures on trunk biomechanics, contribute to more effective estimates of load distribution among passive and active components, enhance our understanding of LBD etiology, and may facilitate future controls/interventions.Ph. D.
10
Russell, Patricia Anne Hartley. "Measurement of the three-dimensional kinematics of the human lumbar and cervical spine using the 3Space Isotrak system". Thesis, Durham University, 1993. http://etheses.dur.ac.uk/5650/.
Testo completo
11
Amell, Tyler K. "The effect of axis placement on measurement of peak moment during isokinetic flexion and extension in the lumbar spine". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq22267.pdf.
Testo completo
12
Gildenhuys, Fourie. "An improved device to measure human response to dorsiflexion and plantar flexion perturbations". Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/96000.
Testo completoAbstract (sommario):
Thesis (MEng) -- Stellenbosch University, 2014.ENGLISH ABSTRACT: The Dorsiflexometer is a device designed and built for the assessment of a patient’s balance capabilities. The birth of the Dorsiflexometer is due to a serious need for physiological balance assessment equipment, capable of conducting dynamic tests in the clinical setting. This is accomplished by recording and analysing the patient’s response to sagittal plane perturbations. The Dorsiflexometer is operated from a computer software interface program. It uses the measurements from a single force plate to calculate four balance metrics’ characterising a patient’s ability to maintain balance. These balance metrics include the sway index, equilibrium score, postural stability index and radius parameter. A single and a double inverted pendulum model of the human body is derived to calculate a patient’s centre of mass movement in the sagittal plane with the measured force plate data and body parameters. Three experiments, involving 48 subjects, were conducted. The experimental tests proved the competency of the machine, the accuracy of both inverted pendulum models and the balance response of seafarers aboard an Antarctic research and supply vessel during rough sea conditions. The tests concluded that the inverted pendulum models can be used to calculate the body centre of mass displacement. The double inverted pendulum model results are more accurate compared with the single inverted pendulum model. During rough sea conditions, the body movement and postural response of seafarers are increased in order to keep themselves upright. The body is furthermore exposed to a fluctuating ground reaction force which may lead to the progression of osteoarthritis and musculoskeletal injuries. The Dorsiflexometer proved to be capable of conducting repeatable assessments and yielding accurate results which can be used to distinguish between balance capabilities.
AFRIKKANSE OPSOMMING: Die Dorsiflexometer is ’n apparaat wat die balansvermoë van pasiënte analiseer. Die masjien is ontwerp en vervaardig weens die groot behoefte aan fisiologiese balans assesserings toerusting wat dinamiese toetse in die mediese sektor kan bepaal. Dit word bereik deur pasiënte se liggaamsreaksie in die sagittale vlak te meet en te assesseer. Die Dorsiflexometer is beheerbaar vanaf ’n rekenaar sagteware koppelvlak program. Die masjien maak gebruik van ’n enkele kragplaat om pasiënte se balans statistieke te meet. Hierdie balans statistieke wat die pasiënte se balans vermoë beskryf en karakteriseer behels die sogenaamde: swaai indeks, balans telling, posturale stabiliteit indeks en die radius parameter. ’n Enkel en dubbel inverse slinger model van die liggaam is afgelei. Hierdie modelle maak gebruik van ’n pasiënt se kragplaat metings en sy liggaamlike parameters om die swaartepunt tydens beweging te bereken. Drie eksperimente, waarin 48 persone betrokke was, is gedoen. Die eksperimente is gedoen om die apparaat se bevoegdheid te bewys, die akkuraatheid van altwee inverse slinger modelle te toets en verder die balans van seevaarders op die Antarktiese navorsings en toevoer skip tydens rowwe see toestande te analiseer. Die toetse het bewys dat die inverse modelle gebruik kan word om die liggaam se swaartepunt te bereken. Die dubbel inverse slinger model resultate is wel akkurater as die enkel slinger model. Daar is bevind dat seevaarders van meer liggaamsbeweging en posturale reaksies gebruik moet maak om orent te bly tydens rowwe seetoestande. Verder word hul liggame blootgestel aan ’n wisselende grond reaksie krag wat kan lei tot die ontwikkeling van osteoarthritis en muskuloskeletale beserings. Die Dorsiflexometer is bewys as ’n aparaat wat wat akurate resultate lewer vir herhaalbare assesserings. Dit kan gebruik word om te onderskei tussen verskillende balans vermoëns.
13
Langford, Nancy Jane. "The Relationship of the Sit and Reach Test to Criterion Measures of Hamstring and Back Flexibility in Adult Males and Females". Thesis, North Texas State University, 1987. https://digital.library.unt.edu/ark:/67531/metadc501137/.
Testo completoAbstract (sommario):
The purpose of this study was to examine the criterion-related validity of the sit and reach test as a measure of hamstring and low back flexibility in adult males and females. Subjects were 52 males and 52 females, 20 to 45 years of age. Hamstring flexibility was measured using a goniometer. Spinal flexibility was measured using a tape measure and an inclinometer. The sit and reach test was performed according to the AAHPERD Health Related Fitness Test Manual. Data were analyzed using correlations and appropriate descriptive statistics. Conclusions of the investigation were: 1) in adult males 20 to 45, the sit and reach test is a valid measure of hamstring flexibility but has questionable validity as a measure of low back flexibility, 2) in adult females 20 to 45, the sit and reach test is a moderately valid measure of hamstring flexibility and is not a valid measure of low back flexibility.
14
Gesbert, Jean-Charles. "Modélisation 3D du rachis scoliotique : fusion de données et personnalisation expérimentale". Thesis, Rennes 1, 2014. http://www.theses.fr/2014REN1S051/document.
Testo completoAbstract (sommario):
Ces travaux s'inscrivent dans le cadre d'un projet de recherche translationnel visant à améliorer la conception des corsets orthopédiques de traitement de la scoliose par la mise en place, par méthode inverse, d'un modèle biomécanique global, simplifié et personnalisé, propre au tronc de chaque patient scoliotique. Ils constituent la première étape de ce projet, à savoir, développer et mettre en œuvre des techniques, outils et protocoles permettant, d'une part, la construction d'un modèle géométrique 3D de la surface externe et des éléments internes du tronc du patient à partir de radiographies bi-planes issues d'un équipement standard et du système Model Maker (Proteor), et d'autre part, la mesure des pressions exercées par le corset ainsi que leur recalage sur les géométries reconstruites. Des reconstructions géométriques 3D du tronc avec et sans corset ainsi que des mesures de pressions ont été réalisées pour 11 patients. La conception d'un unique dispositif de calibration associé à un protocole spécifique permet l'acquisition des différentes données quasi sans déplacements du patient. Sa facilité de transport, d'installation et son faible coût, associés à un temps d'acquisition ne pénalisant pas le confort du patient, rendent envisageable son utilisation en routine clinique. L'utilisation de modèles géométriques paramétriques, associée à des équations de prédiction des paramètres anatomiques, permet d'obtenir une initialisation rapide des géométries des éléments internes du tronc à partir d'un nombre réduit de points anatomiques à numériser. Les mesures de la pression exercée par le corset, effectuées à l'aide d'un dispositif innovant muni de capteurs entièrement réalisés en fibres textiles lui permettant d'épouser parfaitement les courbes anatomiques, ont mis en avant les variations de correction, non négligeables, qu'entraînent la modification de la position du patientThis thesis is a part of a translational research project to improve scoliosis orthopedic brace design through the use, by inverse method, of a simplified and personalized comprehensive biomechanical model for each scoliotic patient’s trunk. It represents the first step of this project, namely, to develop and to implement methods, tools and protocols allowing, on one hand, 3D reconstruction of the external shape and internal components of patient’s trunk from biplanar X-rays (performed with a standard device) and the Model Maker system (Proteor), and on the other hand, measurements of the pressure infered by the brace and their registration on the reconstructed geometry. 3D modeling of the trunk with and without brace as well as pressure measurement were carried out on 11 patients. The development of a common calibration device associated to a specific protocol allows data acquisition nearly without displacements of the patient. Its ease of transportation, installation and a low cost associated with an acquisition time which not penalize the patient’s comfort make possible its use in clinical routine. The use of parametrics geometrical models associated with prediction equations of anatomical parameters provides fast initialization of the geometries of trunk’s internal elements from a reduced number of anatomical landmarks to digitize. Measurements of the pressure infered by the brace, performed thanks to an innovative device made of pressure-sensitive textile fibers allowing it to perfectly fit anatomical curves, have highlighted significant correction variations according to the patient’s position
15
Ronkainen, Jouni A. "Laser based tracking and spin measurement". Thesis, Loughborough University, 2008. https://dspace.lboro.ac.uk/2134/10800.
Testo completoAbstract (sommario):
The sports ball market is extremely competitive and in the US alone valued in excess of $1305 million (SGMA 2008). Original equipment manufacturers (OEMs) are continually trying to create a competitive edge over their rivals. In order to research and develop sports balls it is vital to quantitatively measure launch and flight characteristics of the ball, in an attempt to create a ball that has better flight and/or impact characteristics. A launch or flight monitor allows consistent measurement and benchmarking of the ball under test. Current top of the range soccer ball monitors are assessed for performance. Predominantly the sports engineering community uses high speed video (HSV) cameras in this benchmarking process. This technique however is extremely susceptible to errors in spin measurement. These errors are explored in detail and recommendations are given in order to improve the measurements. The properties of laser light make it an ideal tool for accurate, non-contact measurements. It has gained such widespread use, that living in the 21" century it is inconceivable to avoid laser technology. In this thesis, optical laser techniques are pursued for ball launch angle, velocity and spin measurement. In order to successfully utilise these techniques a system that is capable of accurately steering the laser beam to the desired target is developed. A novel laser tracking system (NLTS) has been designed, developed and proven to work successfully, allowing tracking capability of an arbitrarily moving soccer ball, that has no special fiducials. The system is demonstrated to be capable of measuring the position of the ball in space, therefore the NLTS is capable of acting as a launch monitor. The system is proven to track soccer balls in the laboratory and in a more realistic player testing environment. A valuable design feature is that the natural and ambient lighting conditions are inconsequential for the operation of the system. The tracking technique could be applied to any sports ball and could conceivably be transferred to other applications, e.g. military and automotive. Single point vibrometry work and the NLTS are combined to add spin measurement capability. Actual and measured spin rate values show high levels of similarity when tracking a ball with angular, but no translational velocity. A purpose built 'pendulum rig' is used to carry out measurements on a ball with both translational and angular velocity. The testing highlights how influential the radial measurement distance from the spin axis is, regarding the outputted spin rate value. The current set-up would require further development to allow accurate spin rate measurement using the 'pendulum rig'. The main sources of error and recommendations for future developments of this device are outlined and discussed.
16
Smith, Gregory A. "Continuous Optical Measurement of Cold Atomic Spins". Diss., The University of Arizona, 2006. http://hdl.handle.net/10150/194781.
Testo completoAbstract (sommario):
Quantum measurement is one of the most important features of quantum theory. Although mathematical predictions have been verified in great detail, practical implementation has lagged behind. Only recently have people begun to take advantage of quantum measurement properties to produce new technologies. This research helps fill that technological gap by experimental examination of a continuous, optical measurement for an ensemble of cold atomic spins. The essential physics reduces to the interaction between an atomic ensemble and a weak optical field, which has many well known results. While this work demonstrates many novel applications of the interaction, it also shows that the whole can be more than the sum of the individual parts. Starting with basic characterization of the measurement system using laser-cooled cæsium atoms, the mean value of a spin component is obtained in real time. In essence, the angular momentum of the atomic spins creates a Faraday-like rotation in the polarization of a laser probe beam. With slight modifications, additional spin components are also observed, and are shown to be in good agreement with predictions. In measuring spin dynamics, it is important to account for effects of the probe on the spin states as well. Capitalizing on this as a resource, the probe-induced ac-Stark shift is used to transform a quasi-classical spin-coherent state into a highly quantum Schrödinger cat type of superposition between two spin states. Finally, this work combines all the previous results to demonstrate how a continuous measurement of the spin with a carefully crafted evolution created in part by the probe, allows for nearly real-time determination of the complete spin density matrix. In a single 1.5 millisecond run, a spin density matrix is determined with fidelities ranging from about 85% to 90% across a wide spectrum of test states.
17
Schwab, Adele Ann. "Spin-squeezing of ⁸⁷Rb via optical measurement". Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/45338.
Testo completoAbstract (sommario):
Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Physics, 2008.Includes bibliographical references (p. 55-57).
This project aims to reduce measurement uncertainty in atomic clocks by squeezing the collective spin of atoms. Spin-squeezing reduces noise below the standard quantum limit where precision scales as 1/ [square root of] N, allowing us to instead approach the Heisenberg limit where it scales as 1/N. We report spin-squeezing of the (F = 2, mR = 0) --> (F = 1, mF = 0) hyperfine transition of the 5S1/2 level of ⁸⁷Rb. We also demonstrate a viable setup for the spin-squeezing of the magnetically trappable (F = 2, mF = 1) --> (F = 1, mF = -1) transition, which could potentially be used as a compact frequency standard. This thesis provides a brief theoretical background of spin-squeezing and a summary of the project in its current state.
by Adele Ann Schwab.
S.B.
18
Dahliah, Diana Faraj. "Andreev Spectroscopy Measurement Of GaMnAs Spin Polarization". Miami University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=miami1344427042.
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Pothuganti, Virabadra Phani Raju P. K. "Feasibility study of ultrasound measurements on the human lumbar spine". Auburn, Ala., 2006. http://hdl.handle.net/10415/1302.
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Stockton, John Kenton Mabuchi Hideo. "Continuous quantum measurement of cold alkali-atom spins /". Diss., Pasadena, Calif. : California Institute of Technology, 2007. http://resolver.caltech.edu/CaltechETD:etd-02172007-172548.
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Monat, Heath Barnhart. "Lumbar Skin Profile Prediction from Anterior and Lateral Torso Measurements". The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1343062090.
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22
Furuta, Suguru. "Control and measurement of quantum spins : theory and simulations". Thesis, University of Cambridge, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.615036.
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23
Lai, Wai Cheu. "Spin-spin coupling measurements in solid-state NMR and applications to rhodopsin". Thesis, University of Southampton, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.417982.
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Hauger, Markus. "Measurement of the neutron proton spin correlation parameter Axz /". [S.l.] : [s.n.], 2002. http://edoc.unibas.ch/diss/DissB_6024.
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Chen, Kai, e Shufeng Zhang. "Roles of nonlocal conductivity on spin Hall angle measurement". AMER PHYSICAL SOC, 2017. http://hdl.handle.net/10150/625981.
Testo completoAbstract (sommario):
Spin Hall angle characterizes the rate of spin-charge current conversion and it has become one of the most important material parameters for spintronics physics and device application. A long-standing controversy is that the spin Hall angles for a given material measured by spin pumping and by spin Hall torque experiments are inconsistent and they could differ by as much as an order of magnitude. By using the linear response spin transport theory, we explicitly formulate the relation between the spin Hall angle and measured variables in different experiments. We find that the nonlocal conductivity inherited in the layered structure plays a key role to resolve conflicting values of the spin Hall angle. We provide a generalized scheme for extracting spin transport coefficients from experimental data.
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Mohamad, Haidar Jawad. "Ultrafast optical measurements of spin-polarized electron dynamics in nanostructured magnetic materials". Thesis, University of Exeter, 2015. http://hdl.handle.net/10871/18425.
Testo completoAbstract (sommario):
At present, electronic devices depend upon electric charge to transfer and record information. However, such devices are approaching a scaling limit due to Joule heating. Spintronics offers a solution by exploiting the spin rather than the charge of the electron, since the propagation of spin current can in principle occur without dissipation. Immediate applications lie in magnetic random access memory and novel media for hard disk recording. Within this thesis, the Magneto-optical Kerr effect (MOKE) has been used to measure the static and dynamic magnetic properties of a number of different thin film samples that are of interest for spintronic applications. A femtosecond laser has been used to perform time-resolved MOKE (TRMOKE) and time resolved reflectivity (TRR) measurements simultaneously, which probe the spin and charge dynamics respectively. Measurements have been performed upon a continuous thin film of CrO2 that is known to be half-metallic in bulk form, and a series of YIG/Cu/Ni81Fe19 based structures that are expected to exhibit the spin Seebeck effect (SSE). Chemical vapour deposition (CVD) was used to fabricate the continuous CrO2 thin film on a (100)-oriented TiO2 substrate. Precessional magnetisation dynamics were studied by means of the TRMOKE technique. The dependence of the precession frequency and the effective damping parameter upon the static applied magnetic field were investigated. The precession frequency exhibited a minimum at the hard axis saturation field as expected. However precession was also observed for fields greater than the hard axis saturation value, perhaps suggesting the presence of a twisted magnetic state within the film. TRMOKE and TRR measurements were performed upon the YIG/Cu/Ni81Fe19 based structures for different values of the pump fluence and applied magnetic field. For fixed pump fluence and varying applied field, the frequency of precession is well described by a numerical solution of the Landau-Lifshitz equation for the Ni81Fe19 (permalloy, Py) layer. The frequency, amplitude, damping, phase and chirp of the precessional oscillations was extracted from measurements made with a field of 3 kOe applied at 2.8° from the normal to the sample plane, in a configuration designed to maximise any spin transfer torque (STT) generated by the SSE. The oscillation parameters extracted for trilayer samples and a Py reference sample were found to be very similar. Features indicative of STT predicted by simulations were not observed. This suggests that either the YIG/Cu interface was unable to efficiently transmit spin current within the samples studied here, or else that the STT generated by means of the SSE is too small to be of practical use.
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Parno, Diana Marwick Seymour. "Measurements of the Double-Spin Asymmetry A1 on Helium-3: Toward a Precise Measurement of the Neutron A1". Research Showcase @ CMU, 2011. http://repository.cmu.edu/dissertations/554.
Testo completoAbstract (sommario):
The spin structure of protons and neutrons has been an open question for nearly twenty-five years, after surprising experimental results disproved the simple model in which valence quarks were responsible for nearly 100% of the nucleon spin. Diverse theoretical approaches have been brought to bear on the problem, but a shortage of precise data – especially on neutron spin structure – has prevented a thorough understanding. Experiment E06-014, conducted in Hall A of Jefferson Laboratory in 2009, presented an opportunity to add to the world data set for the neutron in the poorly covered valence-quark region. Jefferson Laboratory’s highly polarized electron beam, combined with Hall A’s facilities for a high-density, highly polarized 3He target, allowed a high-luminosity double-polarized experiment, while the large acceptance of the BigBite spectrometer gave coverage over a wide kinematic range: 0.15 < x < 0.95. In this work, we present the analysis of a portion of the E06-014 data, measured with an incident beam energy of 4.74 GeV and spanning 1.5 < Q2 < 5.5 (GeV/c)2 . From these data, we extract the longitudinal asymmetry in virtual photon-nucleon scattering, A1, on the 3He nucleus. Combined with the remaining E06-014 data, this will form the basis of a measurement of the neutron asymmetry An 1 that will extend the kinematic range of the data available to test models of spin-dependent parton distributions in the nucleon.
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Rudolph, Matthew (Matthew Scott). "Measurement of [gamma](1S) spin alignment with the CMS detector". Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/77489.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2011.In title on title-page, "[gamma]" appears as the lower-case Greek letter. Cataloged from PDF version of thesis.
Includes bibliographical references (p. 135-137).
This thesis presents a measurement of the spin alignment of prompt [gamma](1S) mesons produced in proton-proton collisions at [square root of]s = 7 TeV at the Large Hadron Collider using the Compact Muon Solenoid detector. Approximately 1 fb-1 of data taken during the year 2011 is analyzed. The decay to two muons is used to identify these decays, and the angular distribution of the two muons is measured. The method is designed to measure the tensor polarization with minimal assumptions about the production mechanism involved. The decay distribution of the muons is measured in the full two dimensional angular space as a function of the transverse momentum and rapidity of the [gamma], and the analysis is repeated in the helicity and Collins-Soper frames. A frame invariant quantity is calculated in each frame from the measured decay distribution and compared. The final result disfavors large polarization, but suggests the presence of some anisotropy in the decay
by Matthew Rudolph.
Ph.D.
29
Xing, Zengping. "Magnetoelectric Device and the Measurement Unit". Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/27387.
Testo completoAbstract (sommario):
Magnetic sensors are widely used in the field of mineral, navigational, automotive, medical, industrial, military, and consumer electronics. Many magnetic sensors have been developed that are generated by specific laws or phenomena: such as search-coil, fluxgate, Hall Effect, anisotropic magnetoresistance (AMR), giant magnetoresistance (GMR), magnetoelectric (ME), magnetodiode, magnetotransictor, fiber-optic, optical pump, superconducting quantum interference device (SQUID), etc. Each of these magnetic field sensors has their merits and application areas. For low power consumption (<10uW), quasi-static frequency (<10Hz) and high sensitivity (Ph. D.
30
Horton, Dean. "Testing the SUSY hypothesis though naturalness ans spin measurements". Thesis, University of Oxford, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.543461.
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31
Giles, Brandon L. "Opto-thermal measurements of thermally generated spin current in Yttrium Iron Garnet". The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1503024951599588.
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Anilkumar, Ravi. "Energy-Efficient Measurement of Coverage in Distributed Sensor Networks". Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/9787.
Testo completoAbstract (sommario):
Large-scale sensor networks have become a reality due to recent developments in sensor node hardware and algorithms. Sensor networks can provide real-time information based on detection and tracking. This information cannot be reliable if little is known about the sensor coverage of the network, which can be defined as the total sensing range of the network due to contributions from each sensor node. Knowledge about coverage can also be useful in determining if there is any gap in coverage in the region of interest as well as improving the algorithm that determines the placement of nodes. Although coverage estimation is this thesis's central concern, other factors such as energy-efficiency and network lifespan that affect the network performance are investigated. Energy-efficiency and network lifespan depend on the communication model used for obtaining coverage information from each sensor node. This thesis proposes the use of B-splines for describing coverage efficiently. The properties of B-splines also enable communication models such as directed diffusion and hierarchical clustering to provide better performance as compared to a centralized scheme. Results obtained from simulation experiments indicate that hierarchical clustering and directed diffusion can be used effectively for coverage measurement. The hierarchical clustering model, however, exhibited some drawbacks such as a dependency on the routing scheme and poor node-failure recovery.Master of Science
33
鄧樹恩 e Shu Yan Tang. "Measurement of microwave absorption in cuprate superconductors by electron spin resonance". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1995. http://hub.hku.hk/bib/B31213662.
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Tang, Shu Yan. "Measurement of microwave absorption in cuprate superconductors by electron spin resonance /". Hong Kong : University of Hong Kong, 1995. http://sunzi.lib.hku.hk/hkuto/record.jsp?B17311998.
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35
Dreiser, Jan. "Optical study, preparation and measurement of a single quantum-dot spin". kostenfreifrei, 2007. http://e-collection.ethbib.ethz.ch/view/eth:29799.
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Fersch, Robert G. "Measurement of inclusive proton double -spin asymmetries and polarized structure functions". W&M ScholarWorks, 2008. https://scholarworks.wm.edu/etd/1539623531.
Testo completoAbstract (sommario):
The scattering of polarized electrons from a polarized proton target provides a means for studying the internal spin structure of the proton. The CLAS (CEBAF Large Acceptance Spectrometer) EG1b experiment in Hall-B at Jefferson Laboratory measured double-spin inclusive and exclusive electron-nucleon scattering asymmetries using longitudinally polarized frozen NH3 and ND3 targets and a longitudinally polarized electron beam at 4 different energies (1.6, 2.5, 4.2, 5.6 GeV). Extraction of the virtual photon asymmetry Ap1 (for 0.05 GeV2 < Q2 < 5.0 GeV2) provides precision measurements of the polarized proton spin-structure function gp1 in and above the resonance region. Linear regression of data between the varying energies yields new constraints on the virtual photon asymmetry Ap2 (and thus the structure function gp2 ) in the resonance region (for 0.3 GeV2 < Q2 < 1.0 GeV2). Measurements of these structure functions and their moments allows testing of perturbative Quantum Chromodynamics (pQCD) models and evaluation of moments of the structure functions in the Operator Product Expansion. Testing of Chiral Perturbation Theory (chiPT) at Q2 < 0.2 GeV 2 is enabled by the new data. Other applications of polarized structure functions include measurement of foward-spin polarizability, evaluation of high-order corrections in 1H hyperfine splitting, and testing of quark-hadron duality.
37
McLaughlan, Thomas. "Measurement of spin correlation in top quark pair production at ATLAS". Thesis, University of Birmingham, 2014. http://etheses.bham.ac.uk//id/eprint/4826/.
Testo completoAbstract (sommario):
This thesis presents a study of spin correlation in ttˉ production in the ATLAS detector, in proton-proton collisions, corresponding to an integrated luminosity of 4:7fb\(^1\), with a centre of mass energy of \(\surd\)s = 7 TeV. Both the dilepton and single lepton channels are considered, the latter providing a greater challenge due to the necessity to reconstruct the down-type quark resulting from the W boson decay. A simple technique is employed to reconstruct single lepton ttˉ events, with the transverse angle between the charged lepton and down-type quark used as a probe of the spin correlation. In the dilepton channel, the transverse angle between both charged leptons is used. The extracted value of spin correlation in each channel is consistent with Standard Model predictions, with the result in the e\(\mu\) channel alone sufficient to exclude a model without spin correlation at 7:8\(\sigma\). Also described is the author's contribution to the maintenance and development of the Atlantis Event Display.
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Segal, Michael Ph D. Massachusetts Institute of Technology. "Measurement and control of exciton spin in organic light emitting devices". Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/42245.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2007.Includes bibliographical references (p. 199-215).
Organic semiconductors are a promising new material set for electronic and optoelectronic devices. Their properties can be precisely controlled through chemistry, and they are well-suited for large-area, flexible, and low-cost devices. Optical emission and absorption in these materials is mediated by strongly-bound electron-hole pairs called "excitons". While the function of many organic electronic devices depends on excitons, exciton formation is incompletely understood. This thesis presents a general rate model for exciton formation, and studies formation through three different experimental approaches, in the context of the rate model. First, a novel method for measuring exciton spin statistics is described and implemented. This method avoids several drawbacks common to existing methods, and shows completely randomized exciton spin statistics in two archetypal organic semiconductors: one that is a small molecule, and another that is a polymer. Second, optically-detected magnetic resonance effects in organic semiconductors are shown to be unrelated to exciton formation processes, contrary to the current understanding. A quenching-based model is developed and shown to completely describe the data. Both of these experimental results suggest an absence of spin mixing of exciton precursor states. In the third section of this thesis, this lack of mixing is confirmed both experimentally and through calculation. It is then "turned on" through the introduction of spin-orbit coupling. An approximately three-fold increase in the fluorescent efficiency of an organic light emitting device results.
by Michael Segal.
Ph.D.
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Tipton, Bryan E. "Measurement of polarized parton distributions with spin-dependent deep-inelastic scattering". Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/85351.
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Crook, Nigel Paul. "The application of quantitative environmental magnetic measurements to sedimentary systems". Thesis, Manchester Metropolitan University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248812.
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Morecroft, Deborah. "In-situ magnetoresistance measurements during patterning of spin valve devices". Thesis, University of Cambridge, 2003. https://www.repository.cam.ac.uk/handle/1810/34689.
Testo completoAbstract (sommario):
This dissertation describes an experimental study on the patterning of thin films and spin valve devices. Initially the change in the magnetisation reversal of ferromagnetic Ni80Fe15Mo5 thin films was investigated as the shape anisotropy was increased using optical lithography to pattern wire arrays. These structures show a progressive increase in coercivity and a transition between single and two-stage reversal with increasing milling depth. A similar patterning technique was applied to unpinned (Ni80Fe20/Cu/Ni80Fe20) pseudo spin valve (PSV) structures in order to enhance the coercivity of one of the ferromagnetic layers. The increased coercivity induced by micropatterning changed the natural similarity of the magnetic layers and the structure exhibited a small spin valve response. These initial measurements were carried out with separate milling and electrical characterisation steps. However, it was decided that it would be ideal to design a technique to do in-situ magnetoresistance measurements during milling. This meant that the samples could be milled and characterised in the same step, leading to a much cleaner and more efficient process. In-situ magnetoresistance measurements were carried out during micropatterning of PSV devices, and the measurements showed the evolution in the electrical response as wire structures were gradually milled through the thickness. Contrary to what was expected, the structures showed a maximum spin valve response when fully milled through. The effect of further increasing the shape anisotropy by reducing the wire width, and changing the material properties in the PSV structure has also been investigated. MR measurements were taken as the temperature was increased from 291K to 493K, and the results show that the patterned PSV structures have a better thermal stability than exchange biased spin valves with an IrMn pinning layer. The experiment was extended to the nanoscale, and the results show that a significant increase in MR is not observed despite the fact that the magnetic configuration tends more towards single domain. This is thought to be due to an increase in the initial resistance of the structures. A small increase in MR was observed as the wire width was decreased from 730 to 470 nm, although the spin valve response is heavily dependent on the gallium dosage density during patterning in the Focused Ion Beam (FIB). Micromagnetic simulations were carried out, which agree with the experimental results and showed the change in the magnetisation reversal from rotation to switching as the dimensions were reduced on the nanoscale.
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Dylla, Thorsten. "Electron spin resonance and transient photocurrent measurements on microcrystalline silicon". [S.l. : s.n.], 2004. http://www.diss.fu-berlin.de/2005/209/index.html.
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Anderson, Mark David. "Beam spin asymmetry measurements for two pion photoproduction at CLAS". Thesis, University of Glasgow, 2015. http://theses.gla.ac.uk/6957/.
Testo completoAbstract (sommario):
The overarching goal of this analysis, and the many like it, is to develop our understanding of the strong force interactions within the nucleon by examining the nature of their excitation spectra. As the resonances of these spectra have very short lifetimes (τ = 1 × 10 −23 s) and often have very similar masses, it is often impossible to directly observe them. Polarization observables allow us to study the resonances by looking at how they affect the spin state of final state particles. The beam asymmetry is a polarization observable that allows us to detect the sensitivity of these resonances, and other transition mechanisms, to the electric vector orientation of incident photons. Presented in this thesis are first measurements of the beam asymmetries in the resonant region for the reaction channel γp → pπ+π− focusing on the intermediate mesonic states ρ0 and f0 . The analysis used data from the g8b experiment undertaken at the Thomas Jefferson National Accelerator Facility (JLab), the first experiment at JLab to use a linearly polarized photon beam. Using the coherent Bremsstrahlung facility and the CLAS detector of Hall B at JLab allowed for many multi-channel reactions to be detected and the first measurements of many polarization observables, including those presented here, to be determined. A brief overview of the theoretical framework used to undertake this analysis is given, followed by a description of the experimental details of the facilities used, then a description of the calibration of the Bremsstrahlung tagging facility which the author undertook, and finally the analysis and the resulting measurements are presented.
44
Murakawa, Hiroshi. "Spin anisotropy of Cooper pairs in the spin-triplet superconductor Sr2RuO4 studied by Knight-shift measurements". 京都大学 (Kyoto University), 2007. http://hdl.handle.net/2433/136755.
Testo completo
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Poltera, Carina M. "Numerical analysis of spline generated surface Laplacian for ellipsoidal head geometry". Virtual Press, 2007. http://liblink.bsu.edu/uhtbin/catkey/1371849.
Testo completoAbstract (sommario):
Electroencephalography (EEG) is a valuable tool for clinical and cognitive applications. EEG allows for measuring and imaging of scalp potentials emitted by brain activity and allows researchers to draw conclusions about underlying brain activity and function. However EEG is limited by poor spatial resolution due to various factors. One reason is the fact that EEG electrodes are separated from current sources in the brain by cerebrospinal fluid (CSF), the skull, and the scalp. Unfortunately the conductivities of these tissues are not yet well known which limits the spatial resolution of EEG.Based on prior research, spatial resolution of the EEG can be improved via use of various mathematical techniques that provide increased accuracy of the representation of scalp potentials. One such method is the surface Laplacian. It has been shown to be a direct approach to improving EEG spatial resolution. Yet this approach depends on a geometric head model and much work has been done on assuming the human head to be spherical.In this project, we will develop a mathematical model for ellipsoidal head geometry based on surface Laplacian calculations by Law [1]. The ellipsoidal head model is more realistic to the human head shape and can therefore improve accuracy of the EEG imaging calculations. We will construct a computational program that utilizes the ellipsoidal head geometry in hopes to provide a more accurate representation of data fits compared to the spherical head models. Also, we will demonstrate that the spline surface Laplacian calculations do indeed increase the spatial resolution thereby affording a greater impact to the clinical and cognitive study community involving EEG.Department of Physics and Astronomy
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Xie, Jingyi. "Quantitative measurement of regional cerebral blood flow with arterial spin labelling imaging". Thesis, University of Oxford, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.504384.
Testo completo
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Armstrong, Whitney Richard. "Measurement of the proton A1 and A2 spin asymmetries| Probing color forces". Thesis, Temple University, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=3702966.
Testo completoAbstract (sommario):
The Spin Asymmetries of the Nucleon Experiment (SANE) measured the proton spin structure function g2 in a range of Bjorken x, 0.3 < x < 0.8, where extraction of the twist-3 matrix element d2 p (an integral of g2 weighted by x2) is most sensitive. The data was taken from Q2 equal to 2.5 GeV 2 up to 6.5 GeV2. In this polarized electron scattering off a polarized hydrogen target experiment, two double spin asymmetries, A∥ and A⊥ were measured using the BETA (Big Electron Telescope Array) Detector. BETA consisted of a scintillator hodoscope, gas Čerenkov counter, lucite hodoscope and a large lead glass electromagnetic calorimeter. With a unique open geometry, a threshold gas Čerenkov detector allowed BETA to cleanly identify electrons for this inclusive experiment. A measurement of d2 p is compared to lattice QCD calculations.
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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.
Testo completoAbstract (sommario):
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.
49
Tallini, Hugh Arthur McLaren. "A measurement of the quark spin distributions of the nucleon at HERMES". Thesis, University of Liverpool, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367159.
Testo completo
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Wöhrle, Hartmut. "Measurement of the neutron proton spin correlation parameter Azz at forward angles /". Basel : [s.n.], 2006. http://edoc.unibas.ch/diss/DissB_7464.
Testo completo