Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 21 for “"Axial length"”.
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Refractive error, ocular biometry and oculomotor function: The prevalence of myopia and its potential risk factors in the Middle East, with an investigation of dynamic accommodation responses and axial length fluctuations in young myopic adults.
… accommodative responses and twenty-four hour axial length fluctuations were investigated in young myopic adults. The prevalence of myopia in 3000 Middle Eastern adults (age range 17-40 years) was similar to previously reported levels of myopia in the West. Myopia was associated with a higher …
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Refractive Outcome in Eyes of Preterm Infants
… There were no significant differences in the axial length and anterior chamber depth between group 1 and 3. The degree of myopia was related to laser or cryotherapy treated eyes, birth weight, intrauterine period, and axial length. CONCLUSION: Laser or cryotherapy treated eyes were …
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Analysis of a Hybrid Rocket Burn Using Generalized Compressible Flow
… The variation of the flow properties along the axial length of the port are calculated using a generalized one-dimensional compressible flow analysis. The combined effects of wall mass injection and heat addition are taken into account.</p>
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Ocular biometric change in orthokeratology. An investigation into the effects of orthokeratology on ocular biometry and refractive error in an adult population.
… in agreement with previously published studies. Axial length and anterior chamber depth were unaffected by the treatment. Conclusion; Orthokeratology should be available as an alternative to laser refractive surgery. It is best restricted to myopes of up to -4.00DS with low levels of with the …
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Design and Benchmarking of a Combustor Simulator Relevant to Gas Turbine Engines
… condition to the turbine. Turbulent integral length scales were found to scale well with the dilution hole diameters and no dominant frequencies were observed in the streamwise velocity energy spectra. Dilution flow resulted in an increase in turbulence levels and mixing causing a reduction in …
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Development of capacitive sensor to determine void fraction in horizontal and vertical tubes
… in HVAC&R systems, electrodes with different axial lengths are built together to be compared. The comparison of signals from them show the signals are independent on axial length. Due to the non-uniformity of the electric field between the electrodes of the sensor, a calibration procedure of …
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The design and feasibility of a 10 mN chemical space propulsion thruster
… thickness, each cut to 25%, 50% and 100% axial lengths. The last nozzle is a 100% axial length, ideal contour class, that is twice the thickness to see the effect of end wall boundary layer growth. The nozzles are tested in the MIT Space Propulsions Lab's vacuum chamber at sub atmospheric …
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Visual Performance in Pseudophakia. The Effect of Meridional Blur in Pseudoaccommodation.
… aberrations, corneal multifocality, patient age, axial length). Further, the functionality of meridional blur was evaluated for alphabets in addition to the standard Roman alphabet using a VA task. The results confirm that myopic astigmatism contributes to a better visual performance at closer …
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Self-assembly of helical ribbons from chiral amphiphiles
… of extensions (up to 200% of helix original axial length). The forces involved in the deformation of low pitch helices have been found to be in the 0.25-1.0 nN range making them ideal for use as biological force probes.
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Design optimisation of a slotless brushless permanent magnet DC motor with helically-wound laminations for underwater rim-driven thrusters
… tend to be very thin radially, have very small axial length to diameter ratios, and have relatively large airgaps to accommodate corrosion protection layers on the surfaces of the rotor and stator. The relatively large diameter stator laminations of such machines tend, therefore, to have a very …
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Low-dimensional Models for Real-time Simulation of Internal Combustion Engines and Catalytic After-treatment Systems
… coefficients, spatial averaging over the axial length and simplified chemistry by lumping the oxidants and the reductants. The model performance is tested and validated using data on actual vehicle emissions resulting in good agreement. The computational efficiency and the ability of the …
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Following Ocular Changes in United States Optometry Students (FOCUS): Protocol Development and Baseline Data
… zone area and perimeter were associated with axial length (P < 0.05 for both). Optic nerve head metrics demonstrated variations by sector and eccentricity. Higher order root mean square wavefront error for a 5 mm pupil was 0.22 ± 0.08 µm. Conclusion: A protocol for the FOCUS study was …
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Creep characterization of single crystal silicon in support of the MIT Micro-Engine Project
… application. With a 20 mm diameter and 4 mm axial length, the micro-engine should be able to generate electrical power at over 10 times the power density of a comparably sized battery. Other applications for this technology have been identified, including; propulsion for small unmanned air …
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Solid-liquid mass transfer in trickle bed reactors
… the flow structure is changing as a function of axial length. Lastly, with regards to electrochemical measurements of liquid-solid mass transfer, it was shown that measurements using a single particle electrode compared well to that of a multiple packing electrode.
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Posterior Corneal Astigmatism
… surgery, the most important measurements are the axial length of the eye and corneal shape. The cornea is a three dimensional structure and so, although it has commonly been considered as a single refractive surface, we must take into account that the anterior and posterior surfaces of the cornea …
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How to build a chordate: Multiscale decomposition of axial morphogenesis in the amphioxus, Branchiostoma lanceolatum
… the body plan is the notochord, located at the axial midline, which is flanked dorsally by a neural tube, bilaterally by a metameric pattern of somites, and ventrally by a primitive gut tube. If we are to understand how chordates emerged in evolution, and have subsequently diverged, it is …
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Design and Low-Speed Validation of a Tailored Low-Loss Flow Straightening Device
… flows with approximately constant density and axial velocity, the velocity magnitude decreases and pressure increases along streamlines. This creates an unfavorable streamwise pressure gradient that inhibits the fluids ability to remain attached to the convex suction surface of the turning …
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The association of myopia progression with family history of myopia, nearwork, and other risk factors among Singapore schoolchildren: A 2 year follow-up study
Purpose: To investigate the progression rate of myopia and the possible risk factors among Singapore schoolchildren. Methods: A 2-year follow-up study was carried out among 642 myopic (SER at least - 0.5 D) schoolchildren aged 7-9 years at baseline. Results: The 2-year cumulative progression rate …
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Visuelle und chirurgische Ergebnisse beim kindlichen Glaukom
Das kindliche Glaukom ist eine seltene Erkrankung. Die Patienten müssen ein ganzes Leben lang beobachtet werden. Eine erfolgreiche Operation verlängert zwar die Kontrollintervalle, kann sie aber nicht ersetzen. Ungefähr drei Viertel der Glaukomaugen wurde ein- oder zweimal operiert, bei den übrigen …
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Auswertung von Mehrfachsignalen bei der optischen Achsenlängenmessung
Bei der optischen Achsenlängenmessung des Auges (das auf dem Prinzip der Teilkohärenzinterferometrie beruht)wird das größte Interferenzsignal (Hauptmaximum), das in der Regel vom retinalen Pigmentepithel ausgeht, registriert und zur Bestimmung der Achsenlänge verwandt. Zusätzliche …
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