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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

The Effects of Lead Placement and Sample Shape in the Measurement of Electrical Resistivity

Stephens, Anthony E. 08 1900 (has links)
This thesis is a study of the effects of lead placement and sample shape in the measurement of electrical resistivity.
112

Status Monitoring Of Inflatables By Accurate Shape Sensing

Bond, Justin Matthew 01 January 2017 (has links)
The use of inflatable structures in aerospace applications is becoming increasingly widespread. In order to monitor the inflation status and overall health of these inflatables, an accurate means of shape sensing is required. To this end, we investigated two existing methods for measuring simple curvature, or curvature in one-dimension. The first method utilizes a pair of strain sensing Fiber Bragg Gratings (FBGs) separated by a known distance; dividing the difference in strain by the separation distance yields an experimental value for the one-dimensional curvature at a point. The second method makes use of conductive ink-based flex sensors, which give a variable resistance based on curvature. We used the latter was in a design for a Curvature-Based Inflation Controller (CBIC). While the controller successfully inflated a test body, its overall utility is limited by the simplicity of its sensors. To improve the shape sensing capabilities of the controller, we investigated the use of FBGs in a multidimensional array. We fabricated a curvature-sensing FBG pair on an inflatable membrane and tested its accuracy as the membrane was shaped into a known radius of curvature. This work reports on the assembly of three such curvature-sensing FBG pairs into a two-dimensional Curvature-Sensing Rosette (CSR). The goal is to use this rosette to measure the curvature of a surface in multiple directions at a single point. A 3-D printed surface with saddle geometry was used to calibrate the curvature-sensing rosette. Presented will be methods of extracting values for the tensor of curvature for the surface at a point using the curvature-sensing rosette, along with experimental verification. This essentially defines the local geometry about the rosette, measured in real time. By employing an array of such rosettes across the surface of an inflatable structure, the local curvature of the inflatable could be known at every point. Combining these curvature measurements can yield an accurate depiction of the global geometry. Thus, the inflation status of the inflatable space structure could be monitored in real time.
113

Patterns of osteoarthritic bone change

Shepstone, Lee January 1999 (has links)
No description available.
114

Early recognition of mandibular growth pattern using geometric morphometrics

Graham, Meghan 25 October 2017 (has links)
OBJECTIVE: The objective of this study is to determine the earliest time point in growth when a difference in mandibular shape of dolichocephalic and brachycephalic subjects is distinguishable. MATERIALS & METHODS: 11 dolichocephalic and 14 brachycephalic subjects were selected using lateral cephalograms from the Forsyth/Moorrees Twin Study using a method described by Rocky Mountain Orthodontics. 23 landmarks outlining the mandible were identified on the lateral cephalograms of each subject from their earliest age (5-8 years) to their latest (16-18 years) using TPSdig software. The 2 dimensional coordinates for each landmark were then exported to TPSUtil. From TPSUtil, the TPS data was then converted to a .csv file in Microsoft Excel and imported into MorphoJ for analysis. Primary morphometric analysis consisted of generalized Procrustes analysis, principal component analysis, and discriminant function analysis. RESULTS: The first 5 principal components for both facial types accounted for the majority of the variance. Discriminant function analyses were not significant for any phenotype or age group pairing, suggesting that the overall shape difference was too small to be detected between groups and over time starting at age 7. A plot of the Procrustes coordinates for the brachycephalic group versus the dolichocephalic group revealed that there were differences in shape between the two phenotypes, but this difference was statistically insignificant. CONCLUSIONS: The mandible increases in size with age, with minimal change in shape. Mandibular shape is established by the age of 7. The difference in mandibular shapes of the two phenotypes was not statistically significant.
115

prepositions

Andersson, Sara January 2011 (has links)
Prepositions describes relations between different things. In this collection thosethings refers to the soft and moving body, hard and stiff sculptural shapes, colours,prints, fabrics and shoes.I have a great passion for sculptural shapes and for this collection I have used thispassion as an important source for inspiration. Interesting and challenging meetingsbetween the choice of especially materials and colours is another aspect of this project.Wholeness has a significant meaning to me, as the important thing is not to put focuson the garments themselves rather than the combination of all elements, in the compositionof each outfit and in the line-up. I have looked at the different componentssuch as the sculptural shapes, garments, colours, prints and shoes as if they wherebuilding blocks. I have arranged and rearranged and combined those building blocksin different ways trying to achieve a dynamic and balanced composition. I have triedto simplify all parts as much as possible when aiming for a clear and strong result. / Program: Modedesignutbildningen
116

prepositions

ANDERSSON, SARA January 2013 (has links)
Prepositions describes relations between different things. In this collection thosethings refers to the soft and moving body, hard and stiff sculptural shapes, colours,prints, fabrics and shoes.I have a great passion for sculptural shapes and for this collection I have used thispassion as an important source for inspiration. Interesting and challenging meetingsbetween the choice of especially materials and colours is another aspect of this project.Wholeness has a significant meaning to me, as the important thing is not to put focuson the garments themselves rather than the combination of all elements, in the compositionof each outfit and in the line-up. I have looked at the different componentssuch as the sculptural shapes, garments, colours, prints and shoes as if they wherebuilding blocks. I have arranged and rearranged and combined those building blocksin different ways trying to achieve a dynamic and balanced composition. I have triedto simplify all parts as much as possible when aiming for a clear and strong result. / Program: Modedesignutbildningen
117

[en] STRUCTURAL BEHAVIOUR OF COMPOSITE SLAB WITH CORRUGATIONS IN THE COLD FORMED SECTION PROFILES WEB / [pt] COMPORTAMENTO ESTRUTURAL DE LAJES-MISTAS COM CORRUGAÇÕES NA ALMA DE PERFIS DE CHAPA DOBRADA

ALLYSON JOSE DO NASCIMENTO BELTRAO 13 January 2004 (has links)
[pt] Este trabalho apresenta um estudo de um sistema de laje mista com o uso de perfis metálicos de chapa dobrada com corrugações na alma e chapa de vedação lateral com mossas seqüencialmente dispostos lado a lado e preenchidos com concreto armado. A principal motivação para este estudo foi o desenvolvimento de um eficiente sistema de laje de rápida construção. O sistema de laje desenvolvido maximiza o espaço livre útil da construção, eliminando a necessidade de formas e escoras tendo assim como conseqüência direta a minimização das perdas construtivas. Este trabalho é iniciado com uma avaliação da forma ideal dos perfis de chapa dobrada de acordo com as suas características estáticas e dinâmicas. Variáveis como peso, altura, espessura, tensão de escoamento, vão máximo, e carga suportada foram estudadas. Além disso foi feito um estudo para confecção das ferramentas de fabricação das corrugações e mossas na alma do perfil e na chapa de vedação lateral de forma eficiente e econômica. Após definição e otimização da seção do perfil metálico, foi efetuado um estudo experimental composto de uma série de três testes em escala real. O objetivo principal dos testes experimentais foi de comprovação dos resultados teóricos de resistência ultima da laje mista com perfis corrugados na alma e efetuar uma comparação com o sistema de laje previamente proposto por Takey. Os testes demostraram a real aderência entre concreto e perfil metálico e sua influência nos estados limites últimos de flexão, cisalhamento e deslizamento. Ensaios tipo push-out também foram executados para estabelecer a carga ultima de deslizamento na interface aço/concreto. A fase final compreendeu a comparação dos resultados experimentais com as normas de projeto de laje mista e com o trabalho desenvolvido por Takey para validação e comparação de resultados do sistema de laje mista. / [en] This work presents an investigation of a composite slab system made of cold formed section profiles with web corrugations and corrugated steel deck plates spanning between suck profiles, both acting compositely with concrete slab cast in place. The main motivation for this work was the development of an efficient slab system associated with easy and fast erection procedures. The proposed slab system also maximises the construction usable space, eliminating the use of temporary propping and, consequently reducing the final construction cost. This work initiates with an evaluation of the ideal cold- formed steel profile geometry according to its static and dynamical characteristics. Variables like weight, height, thickness, yield stress, and collapse load were considered. Additionally, a study of the more suitable fabrication tools to be used in the process of incorporating the corrugations to the profile webs and deck supporting plates was executed. With the optimum steel profile in hand, an experimental investigation of three full scale composite slabs, spanning three meters, was conducted. The main objective of these tests was to access the ultimate limit states associated with the proposed composite slab system and compared it to a previously proposed solution, developed by Takey. The tests made possible the evaluation of the concrete versus steel slippage resistance when compare to the other ultimate limit states associated with flexion and shear. The adopted solution, despite the natural chemical bond present in the steel/concrete interface, enhances its performance due to the action of the web profile corrugations. Push-out tests were also executed to enable the determination of the ultimate slippage load in the steel/concrete interface due to the presence of the proposed corrugations. The final stage of this investigation concerned the comparison of the experimental data to the current composite design standards, and to the previous system, developed by Takey, in order to validate its use.
118

Protein shape description and its application to shape comparison

Tykac, Michal January 2018 (has links)
There are currently over 138, 000 known macromolecular structures deposited in the wwPDB (Worldwide Protein Data Bank) database. While all the macromolecular structure files contain information about a particular structure, the collection of these files also allows combining the macromolecular structures to obtain statistical information about macromolecules in general. This fact has been the basis for many structural biology methods including the molecular replacement method used in X-ray crystallography or homologous structure restraints in the refinement methods. With the success of methods based on prior information, it is feasible that novel methods could be developed and current methods improved using further prior information; more specifically, by using the structure density-map shape similarity instead of sequence or model similarity. Therefore, this project introduces a mathematical framework for computing three different measures of macromolecular three-dimensional shape similarity and demonstrates how these descriptors can be applied in symmetry detection and protein-domain clustering. The ability to detect cyclic (C), dihedral (D), tetrahedral (T), octahedral (O) and icosahedral (I) symmetry groups as well as computing all associated symmetry elements has direct applications in map averaging and reducing the storage requirements by storing only the asymmetric information. Moreover, by having the capacity to find structures with similar shape, it was possible to reduce the size of the BALBES protein domain database by more than 18.7% and thus achieve proportional speed-up in the searching parts of its applications. Finally, the development of the method described in this project has many possible applications throughout structural biology. The method could, for example, facilitate matching and fitting of protein domains into the density maps produced by the electron-microscopy techniques, or it could allow for molecular-replacement candidate search using shape instead of sequence similarity. To allow for the development of any further applications, software for applying the methods described here is also presented and released for the community.
119

Landmark-based approach to examining changes in arch shape: a longitudinal study

Varner, Taylor Blake 01 May 2015 (has links)
Objective: Variation in dental arch shape and arch relations from the primary to the permanent dentition were studied in an untreated longitudinal sample from the Iowa Fluoride Study and Growth Study data (55 females and 63 males). Methods: 3D coordinate data from 68 landmarks located on maxillary, mandibular, and occlusal dental cast scans from ages 5, 9, and 13 were submitted to a Procrustes fit prior to a Principal Component (PC) analysis to capture symmetric and asymmetric aspects of arch shape variation. Covariance pattern models were used to determine longitudinal arch shape changes from the primary to the permanent dentition and to correlate these changes with Angle class molar classification. Results: The first 3 principal components capture 52-78% of the variation in arch shape. PC1 explains 30-44% of the variance and captures changes in overall dentoalveolar height. PC2 explains 14-22% and shows mainly variation in dentoalveolar height and width at the canines. Lastly, PC3 explains 8-12% and captures overall arch width and perimeter differences and changes in anteroposterior arch relations. Results on symmetric shape variation for the occlusal data set captured significant differences (p < 0.0001) in morphology for PC2 and PC3. For PC2, initial morphology in the deciduous dentition for an individual classified as Class II was significantly different than a Class I individual. Initial shape characteristics for the Class II features stepped down maxillary incisors and an increased curve of Spee with deep overbite. For PC3, the initial morphology for both the distocclusion and Class II individuals demonstrated characteristics such as stepped up maxillary incisors and increased overjet relative to their flush terminal plane and Class I counterparts. The rate of arch shape changes at which the distal step group transitions to the mixed dentition was also significantly different from the flush terminal plane sample. Conclusions: Initial findings summarize the main aspects of arch shape variation throughout 3 dentition stages. The covariance pattern models estimated individual trajectories and dynamics of arch shape changes from the primary to the permanent dentition and correlated these changes with Angle molar classification. In the symmetric dataset, significant shape characteristic differences of both initial starting morphology and change in shape over time were discovered for two occlusal phenotypes highlighting differences primarily in the vertical and anteroposterior dimensions. The results found in the present study provide an excellent foundation for describing and identifying dental arch shape differences in the primary dentition that can aid in earlier detection, diagnosis, and treatment of malocclusion, or at a minimum warrant closer observation by the clinician.
120

Candidate gene analysis of 3D dental phenotypes in patients with malocclusion

Weaver, Cole Austin 01 May 2014 (has links)
Objectives: About 2% of the US population suffers from severe malocclusion discrepancies that are beyond the limits of orthodontics alone. This study explores correlations between 3D malocclusion phenotypes and craniofacial development genes. Methods: CBCTs (124) or digital casts (161) of 285 subjects with skeletal Class I (n=60), II (n=143) and III (n=82) malocclusion were digitized with 48 dental landmarks. 3D coordinates were superimposed prior to Principal Component (PC) analyses to identify symmetric (sym) and asymmetric (asym) aspects of shape variation related to malocclusion. PCs explaining 51%-67% of total shape variation were regressed on 200 variants genotyped within 75 genes adjusting for race, gender, age and data source. Results: Significant correlations (p<0.01) were found for sym variation with BMP3, PITX2, MAFB, SNAl3, FGF8, ABCA4-ARHGAP29, FOXL2 and asym variation PAX7, TBX1, LEFTY1, SATB2, SOX2, TP63 and the 400Kb region containing D1S435. Conclusion: Results suggest genetic pathways associated with malocclusion.

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