1,721,144 research outputs found
A Complementary Response to Anthony Brian Taylor
Full text linkThis essay is a response to Anthony Brian Taylor's "Arthur Golding and the Elizabethan Progress of Actaeon's Dogs.
Photopolymerised urethane acrylates / Anthony Brian Clayton
Full text linkIncludes bibliographical referencesxi, 228 leaves : ill ; 30 cm.Thesis (Ph.D.)--University of Adelaide, Depts. of Physical and Inorganic Chemistry and Chemical Engineering, 199
Popular Religious Radio Programs (A Content Analysis)
Full text linkA thesis presented to the faculty of the Caudill College of Humanities at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Arts by Anthony Brian Corea in July of 1995
Single frequency and high power operation of diode-pumped solid-state lasers
No full textIn recent years, advances made in semiconductor diode lasers have led to a resurgence in the development of solid-state lasers. Diode-pumped solid-state lasers (DPSSLs) are typically more compact, efficient, reliable and economical than alternative laser sources. In this thesis two areas of research in the field of DPSSLs have been investigated namely, single frequency ring lasers and high power diode bar pumped solid-state lasers.Single frequency laser sources are important in a wide range of applications, and a number of methods are available for producing single frequency operation. In this work an acousto-optic modulator was used in a ring laser cavity to enforce unidirectional operation, which in turn can produce single frequency output. Acousto-optic devices can provide a simple, low-loss means of enforcing unidirectional operation in ring lasers, compared to other methods. Previously, the means by which this was accomplished was not understood. Here, two distinct mechanisms are described that can be used to enforce unidirectional operation, experimental verification is provided, and the implications that this has for the development of single frequency sources are discussed. Ring lasers were also constructed which operated at wavelengths of 1.3µm and 2µm, using acousto-optic modulators to produce unidirectional operation.Diode bar lasers have recently emerged as one of the most economical pump sources for solid-state lasers, and are capable of producing high output powers in side-pumping geometries. In this thesis, the use of diode bars in end-pumping configurations is explored, as such systems potentially offer much higher efficiencies than side-pumping, and should be more suitable for output powers up to a few tens of watts. A significant problem with diode bar end-pumped systems is that the dimensions of the diode bar (10mm x 1µm) make it difficult to effectively couple their output into the lasing mode of a solid-state laser. In this thesis, initial attempts to end-pump lasers are described. Some degree of success was obtained. Also presented is a novel optical arrangement that manipulates the diode bar output to produce a beam with a much higher degree of symmetry, and hence, suitability for end-pumping. This system, using just two mirrors to chop up and rearrange the diode beam, has applications in a wide variety of situations involving laser beams with a large difference in dimensions and divergence properties in two orthogonal directions, and should allow diode bars to be effectively used for end-pumping solid-state lasers. Preliminary results for end-pumping a solid- state laser are presented, which offer great promise for optimised laser systems
Enhanced ultrasound for advanced diagnostics, ultrasound tomography for volume limb imaging and prosthetic fitting
Full text linkUltrasound imaging methods hold the potential to deliver low-cost, high-resolution, operator-independent and nonionizing imaging systems-such systems couple appropriate algorithms with imaging devices and techniques. The increasing demands on general practitioners motivate us to develop more usable and productive diagnostic imaging equipment. Ultrasound, specifically freehand ultrasound, is a low cost and safe medical imaging technique. It doesn't expose a patient to ionizing radiation. Its safety and versatility make it very well suited for the increasing demands on general practitioners, or for providing improved medical care in rural regions or the developing world. However it typically suffers from sonographer variability; we will discuss techniques to address user variability. We also discuss our work to combine cylindrical scanning systems with state of the art inversion algorithms to deliver ultrasound systems for imaging and quantifying limbs in 3-D in vivo. Such systems have the potential to track the progression of limb health at a low cost and without radiation exposure, as well as, improve prosthetic socket fitting. Current methods of prosthetic socket fabrication remain subjective and ineffective at creating an interface to the human body that is both comfortable and functional. Though there has been recent success using methods like magnetic resonance imaging and biomechanical modeling, a low-cost, streamlined, and quantitative process for prosthetic cup design and fabrication has not been fully demonstrated. Medical ultrasonography may inform the design process of prosthetic sockets in a more objective manner. This keynote talk presents the results of progress in this area. Keywords: Clinical ultrasound, Force control, 3-D ultrasound, Tomograph
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
The relationship between structure and seismogenic behaviour in subduction zones
No full textThe largest earthquakes on Earth take place on the megathrusts of subduction zones, but the slip behavior of megathrusts is variable. This thesis considers why by conducting local, regional and global studies of the interrelationships between the structure and seismogenic behavior of subduction zones. New marine geophysical data collected from the collision zone between the Louisville Ridge seamount chain with the Tonga-Kermadec trench constrain overthrusting and subducting plate structure. Mo'unga seamount is identified beneath the outer-forearc, which calibrates the association of residual bathymetric anomalies and subducting relief, implies an E-W geometry for the subducted ridge and suggests the 200 km wide Louisville seismic gap is modulated by the sediment filled flexural moat. Spectral averaging is then applied along the Tonga-Kermadec margin and along strike variations in overthrusting plate structure are verified by wide-angle seismic transects. The remnant Tonga-Ridge occupies the inner fore-arc and residual free-air gravity anomalies constrain its latitudinal extent (north of 30.5°S), width (110±20 km) and strike (~005° south of 25°S). Plate tectonic reconstructions suggest the Lau Ridge is unmodified by subduction related erosion, <200 km of the Tonga Ridge has been eroded, and neither ridge ever occupied the southern Kermadec arc. Crustal thickness variations are thus inherited, reflecting the Cenozoic tectonic evolution of the Tonga-Kermadec-Hikurangi margin. Spectral averaging is finally applied to all subduction zones on Earth. Part one develops a global catalogue of subducting relief, which is compared with seismological and geodetic inferences of fault-slip behavior. Most seamounts are aseismic, relatively undeformed and observations are not consistent with mechanical models proposing full-decapitation. Aseismic ridges are also associated with megathrust complexity, but are of a larger wavelength and contrasting mode of isostatic compensation. Part two shows almost all intra-margin along-strike transitions in seismogenic behavior are related to pre-existing crustal structure. A paired forearc anomaly is interpreted consisting of a trench-parallel ridge landward of the deep-sea-terrace basin. The ridge crest correlates with the down-dip limit of coseismic slip and strong interplate coupling, the up- dip limit of tremor epicentres, and is interpreted as defining the boundary between the velocity-weakening and seismogenic portion of the subduction interface and the down-dip frictional transition zone. Paired anomalies may be attributed to unrecovered interseismic elastic strain, the preferential subduction erosion of the outer-forearc and/or underplating beneath the inner forearc
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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