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Dissertations / Theses on the topic 'Arch width'

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Published: 4 June 2021
Last updated: 13 February 2022

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1

MacKriel, Earl Ari. "Changes in arch dimensions after extraction and non-extraction orthodontic treatment." Thesis, University of the Western Cape, 2008. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_4464_1260523586.

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The aim of this study was to determine whether there are changes in the interdental arch widths and arch lengths of the mandibular and maxillary arches during nonextraction and extraction orthodontic treatment. The records of 78 patients treated by one orthodontist were used for this study. Three treatment groups were selected: a nonextraction group (Group NE), a group treated with extraction of maxillary and mandibular first premolars (Group 44), and a group treated with extraction of maxillary first premolars and mandibular second premolars (Group 45). The arch width measurements were measured in the inter-canine, inter-premolar and inter-molar areas. The arch length was measured as the sum of the left and right distances from mesial anatomic contact points of the first permanent molars to the contact point of the central incisors or to the midpoint between the central incisor contacts, if spaced.

Statistical analysis included descriptive statistics of the data, analysis of the correlation matrices, Wilcoxon Signed Rank tests and Kruskal-Wallis tests of the changes which occurred during treatment. The intercanine widths in the mandible and maxilla increased during treatment in all three groups, with the extraction groups showing a greater increase than Group NE (p<
0.05). In Group NE the mandibular arch length increased (p<
0.05), while the maxillary arch length remained essentially unchanged. Both extraction groups showed decreases in arch length in the dentitions (p<
0.05), with greater decreases occurring in the maxilla. The difference in arch length change between the two extraction groups was not significant (p>
0.10). The inter-canine arch width increased in all three treatment groups, more so in the two extraction groups. From this it is evident that extraction treatment does not necessarily lead to narrowing of the dental arches in the canine region. The inter-second premolar arch width decreased in both extraction groups. Non-extraction treatment resulted in an increase in the inter-premolar and inter-molar arch widths.

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Raan, F. J. du. "Using a mathematical model to determine dental arch- perimeter in class ii patients presenting at UWC orthodontic clinics." University of the Western Cape, 2021. http://hdl.handle.net/11394/7976.

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Doctor Scientiae - DSc
Determining arch perimeter is of importance in both a clinical setting, where it is used to determine space requirements, as well as in an epidemiological setting where it is used to describe large populations. Physical measurement of arch perimeter is time consuming and may be prone to operator errors when done on study casts and even more so in a clinical situation. The use of a simple mathematical model to predict arch perimeter, using a few measurements that can be done easily and reliably, would be of great use to the practitioner.
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Bachtiar, Mulyani Dalidjan. "An assessment of Pont's Index to predict dental arch width in human populations /." Title page, contents and summary only, 1990. http://web4.library.adelaide.edu.au/theses/09DM/09dmb124.pdf.

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4

Aynaciyan, Raffi J. "Rapid maxillary expansion long-term hard tissue profile and dental arch width changes /." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0025/MQ30661.pdf.

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5

Katz, Robert Adam. "The Long Term Stability of Mandibular Arch Length and Width Changes Following Rapid Maxillary Expansion." The Ohio State University, 1990. http://rave.ohiolink.edu/etdc/view?acc_num=osu1383819575.

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6

Sacksteder, James Martin. "Dental Arch Width and Length Parameters in Patients with Obstructive Sleep Apnea vs Patients Without: A Pilot Study." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1490040724141358.

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7

Suga, Selma Sano. "Avaliação do posicionamento de caninos superiores permanentes na fase da dentadura mista em relação à largura do arco dentário e ao espaço na região anterior." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/23/23132/tde-17092008-100018/.

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Este estudo avaliou o posicionamento de caninos superiores permanentes em relação à largura do arco dentário superior e ao espaço na região anterior em pacientes na fase da dentadura mista. Foram analisados radiografias panorâmicas e modelos de estudo pré-tratamento de pacientes sem caninos deslocados (n = 68; 34 do gênero masculino; 34 do gênero feminino). A amostra foi dividida em idade e gênero. A largura do arco dentário e o espaço na região anterior entre os incisivos permanentes foram medidos. A posição e a inclinação do canino na radiografia panorâmica foram avaliadas em relação à linha mediana. Os resultados deste estudo mostram que não houve diferenças no posicionamento dos caninos permanentes em relação às variáveis analisadas. A média da angulação do canino superior em relação à linha mediana foi 6,2o e 10o para o gênero feminino e 9,2o e 11o para o masculino, respectivamente para o lado direito e esquerdo.
This study investigated the correlation between maxillary dental arch width, anterior space and the position of canines in patients during the mixed-dentition stage. Pretreatment Panoramic radiographs and dental casts were evaluated of randomly selected patients in the mixed dentition without maxillary canines displaced (n = 68; male, 34; female, 34). This sample was matched according to sex and age. Arch widths between the maxillary canines deciduous and anterior space between permanent incisors were measured and recorded. The position and inclination of canine on panoramic radiography was investigated. The results of this study showed that there are similarities in the position of the permanent canines in all cases and in both gender. The average of the canine\'s angulation to the mid-sagital plane was 6,2o and 10o for female and 9,2o and 11o for male, respectively to the right and left side.
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8

Walker, Becky J. "A comparison of mandibular arch width changes using two different bracket systems : a randomised controlled clinical trial." Thesis, University of Bristol, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.681744.

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AIMS: The primary aim was to assess and compare mandibular arch width changes between self-ligating and non-self-ligating brackets using superelastic nickel titanium archwires. DESIGN: Single-centre prospective randomised controlled clinical trial. SETTING: Orthodontic department, Queen Alexandra Hospital, Portsmouth. PARTICIPANTS: 92 consecutive patients seen in the department who fulfilled the selection criteria. INTERVENTIONS: All patients were treated with upper and lower fixed appliances on a nonextraction basis. Patients were randomly assigned to Damon Q self-ligating or Orthos non-selfligating brackets in a ratio 1:1. Both groups received the same archwire sequence. Impressions were taken pre-treatment (TO) and 8 weeks after placement of the following archwires: 0.014// CuNiTi (TlL 0.014// x 0.025// CuNiTi (T2L 0.018// x 0.025// CuNiTi (T3). OUTCOME MEASURES: Intercanine, first and second interpremolar and intermolar widths were measured at all timepoints using digital callipers and a three-dimensional laser scanner. Perceived pain and anxiety levels were measured using questionnaires. Any breakages occurring during the study were recorded. RESULTS: There were statistically significant differences between Damon Q and Orthos in lower intercanine width at Tl (calliper p=0.031; laser p=O.017L T2 (calliper p=0.006; laser p=O.027) and T3 (calliper p=0.002; laser p=O.OOl); lower second interpremolar width at T3 (calliper p=0.009; laser p=0.009) and lower intermolar width at T3 (laser p=0.036). Orthos had the higher value for all of these differences. No findings were considered clinically significant. Pain scores were significantly higher for Orthos at TO, significantly higher for Damon at Tl, with no significant difference at T2. There was no significant difference in anxiety scores between the 2 groups. A record of breakages showed that Damon had more IIArchwire out// and Orthos 110 ring// failures than would be expected. CONCLUSION: There is no clinically significant difference between Damon Q self-ligating and Orthos non-self-ligating brackets in arch width changes when using superelastic nickel titanium archwires.
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Bezerra, Valeria Matos. "Alterações das dimensões dos arcos dentários e das inclinações dos incisivos produzidas pelo Sistema Damon." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/25/25144/tde-05042013-102219/.

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PROPOSIÇÃO: O objetivo deste trabalho foi descrever as alterações das dimensões dos arcos dentários e das inclinações dos incisivos produzidas pelo Sistema Damon, durante a fase de alinhamento e nivelamento. Outro objetivo foi verificar a correlação destas alterações com o padrão de crescimento dos indivíduos. MATERIAL E MÉTODOS: modelos de estudo, telerradiografias convencionais e telerradiografias reconstruídas a partir de tomografias computadorizadas cone-beam de 22 casos tratados com o bráquetes Damon 3MXTM foram avaliados durante a fase de alinhamento e nivelamento. Os modelos de estudo foram obtidos ao início do tratamento (T0), após a primeira troca de fio (T1) e na inserção do fio de aço 0,019 x 0,025 (T2). Foram verificados os comprimentos de arco e as dimensões transversais nas regiões de caninos, primeiros e segundos pré-molares e primeiros molares mensuradas a partir das pontas de cúspides e margens gengivais linguais dos dentes, a cada etapa. Nas telerradiografias foram verificadas as alterações das inclinações dos incisivos inferiores e superiores, bem como o padrão de crescimento dos indivíduos. RESULTADOS: os comprimentos dos arcos e todas as distâncias transversais apresentaram aumentos significantes, com exceção da distância intercervical dos caninos superiores; houve aumento significante das inclinações vestibulares dos incisivos superiores e inferiores; o padrão de crescimento dos pacientes apresentou correlação significante com os aumentos transversais na região de pré-molares inferiores. CONCLUSÕES: o alinhamento e nivelamento de casos tratados sem extrações com o uso do Sistema Damon resultou no aumento significante das dimensões dos arcos dentários e das inclinações dos incisivos para vestibular.
OBJECTIVE: This study aimed to evaluate the dental arch widths and incisor torque changes produced by the Damon System during leveling and alignment. Other objective was to verify the correlation between these changes and the growth pattern. MATHERIAL AND METHODS: study casts and lateral radiographs derived from cone-beam computed tomographies of 22 subjects treated with Damon 3MXTM brackets were evaluated. The study casts were obtained at the start of treatment (T0), the first archwire change (T1), and the placement of the final 0,019 x 0,025-in archwire (T2). Arch depth and widths (intercanine, interpremolar and intermolar) were assessed at each stage. The incisor torques changes and the growth pattern were measured on the cephalometric records at T0 and T2. RESULTS: There was significant increase of the arch depths and lateral expansion of the arches for all measures, except for the intercervical of maxillary canines. The maxillary and mandibular incisors were significantly tipped labially; the growth pattern showed significant correlation with the lateral increases in lower premolars region. CONCLUSIONS: nonextraction cases treated with Damon System show significant increases in arch dimensions and incisors proclination.
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10

Seon, Hongsun 1965. "Electrode erosion and arc stability in transferred arcs with graphite electrodes." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=108637.

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Arc stability and erosion behavior were studied on a hollow graphite DC cathode in an argon atmosphere at atmospheric pressure. It was found that the arc stability is associated with the electron emission mode transition of the cathode operation. Estimation of current densities, SEM pictures, Fast Fourier Transform (FFT) of total voltage, and measurement of cathode surface temperature supported this. Stable arcs are in the thermionic emission regime while unstable arcs in the thermofield emission regime. Higher argon gas flow rate is believed to cause the shift of the mode from the thermofield emission to the thermionic emission by increasing the arc root temperature through steepening the thermal gradient at the arc root and increasing ionization phenomena inside the arc. Sharp cathode tip geometry usually leads to the thermionic emission while a rounded tip geometry encourages the thermofield emission. For the unstable arcs, the high voltage fluctuation resulted from the jumping of the arc root between different cathode spots and changes in the arc length. In the stable arcs, however, the voltage was almost constant because of the absence of arc jumping. The standard deviation of the voltage was used as the arc stability indicator and was less than 3 V for the stable arc in this transferred arc system.
The erosion rate of the cathode in this work ranged from 0.41 to 2.61 mug/C. At 150 A runs the arc stability strongly influenced the erosion rate; as the arc stability increased, the erosion rate decreased. Higher currents runs (300 and 400 A), however, showed the opposite trend because of the carbon vapor redeposition. The total erosion rates of 150 A runs were separated into the stable (Es) and the unstable (Eu) erosion rate. The Eu was more than 3 times higher in this work. It is believed that the thermofield emission of the unstable arcs produced more erosion because of the higher local heat flux to the cathode spots.
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11

Aagard, Adam D. "Rectification of 2-D to 3-D Finite Element Analysis in Buried Concrete Arches Under Discrete Loading." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd1768.pdf.

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12

Wermerson, Christopher Paul. "Comparison of tooth widths, arch widths, arch lengths in early mixed and permanent class I normal dentitions to class I and II crowded dentitions." Thesis, University of Iowa, 2016. https://ir.uiowa.edu/etd/3214.

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This thesis compared tooth widths, arch widths, and arch lengths; their differences between males and females, and changes from early mixed dentitions to adult dentitions. Comparing subjects who were known to have Angle Class I normal occlusion in their permanent dentitions to subjects who were known to be Class I or Class II crowded malocclusions in their permanent dentitions. These comparisons can only be achieved utilizing data from a longitudinal study, such as the Iowa Growth Study. Dental casts in the early mixed dentition (average age of 8.85 years) and in the adult dentition (average age 15.45 years) taken from subjects who did not receive orthodontic treatment during or in the dates prior to data collection were measured for this study. The casts utilized were from the Iowa Growth Study; all of the subjects were of European descent. The longitudinal sample of casts in the Iowa Growth study were made from white dental stone poured into alginate impressions from 1946 until 1960. The objectives of this study were to compare individual tooth widths, mean sum tooth widths, arch widths, arch length segments, and arch perimeters of Class I Normal (CIN) and Class I and II crowded dentitions (CD) in the early mixed (MD) and permanent (PD) dentitions to explore new methods of predicting crowding. The goal was to evaluate the significance of differences between MD and PD for tooth widths, arch lengths, and arch widths in both arches of CIN and CD subjects to determine values that may be useful for MD space analysis. Thirty males and thirty females from the Iowa Growth Study with CIN and CD occlusions were selected from the longitudinal study. Casts of MD and PD subjects were double measured with digital calipers by both the primary and secondary investigators. The average of each investigator's two measurements were used to determine measurement error. All other statistical analysis was based on the mean measurements taken by CPW. Descriptive statistics were computed. The normal non-crowded and crowded samples were compared with two-sample t-test, and changes from MD to PD with paired-sample t-test. Examiner measurement errors were tested with intra-class correlation coefficients. When the mean sums of MD and PD tooth widths were compared, using data from all 60 subjects, the CD group had a significantly greater mean sum of tooth widths than the CIN group. In both genders, crowded dentitions had significantly greater mean sum of tooth widths than CIN's for both the maxilla and mandible in MD and PD. When the mean sums of the arch lengths [Perimeters] were compared using data from all 60 subjects, the arch perimeters of the CD and CIN samples did not differ. It was concluded that total arch lengths Perimeters] were not significant indicators for crowding. Gender comparisons: Within the CIN group, males had numerically larger tooth width sums and arch length sums than females. The sum of maxillary and mandibular tooth widths for CIN's and CD (both males and females) mandibular tooth widths for CIN's and CD (both males and females pooled together and sexes separately. In the MD stage the mean sum of maxillary and mandibular arch lengths in the MD were significantly greater than those in the PD, because arch perimeters decrease during the transition from mixed to permanent dentitions. In summary, the results of this research thesis study showed that the sum of tooth widths in both arches had a significant association with dental crowding. In contrast, the sum of arch lengths [perimeter in both arches] did not differ between the normal and crowded samples. Additional analysis of the measurements taken in this thesis research project, the individual arch length segments, especially the canine and posterior arch length segments in the right and left sides of the lower arch in the mixed dentition casts, and their relation to the sum of the widths of the lower permanent canines and premolars in the normal and crowded malocclusions may give us important information about the development of crowded malocclusions.
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Enocksson, David, and Joakim Skoog. "Evaluating VaR with the ARCH/GARCH Family." Thesis, Uppsala universitet, Statistiska institutionen, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-168283.

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The aim of the thesis is to identify an appropriate model in forecasting Value-at-Risk on a morevolatile period than that one from which the model is estimated. We estimate 1-day-ahead and10-days-ahead Value-at-Risk on a number of exchange rates. The Value-at-Risk estimates arebased on three models combined with three distributional assumptions of the innovations, andthe evaluations are made with Kupiec's (1995) test for unconditional coverage. The data rangesfrom January 1st 2006 through June 30th 2011. The results suggest that the GARCH(1,1) andGJR-GARCH(1,1) with normally distributed innovations are models adequately capturing theconditional variance in the series.
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Baker, Martin G. "Finite element analysis of masonry with application to arch bridges." Thesis, Cardiff University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284492.

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Elmubarak, Mona Dr. "Accuracy and reliability of traditional measurement techniques for tooth widths and arch perimeter compared to CAD/CAM." The University of the Western Cpae, 2018. http://hdl.handle.net/11394/6472.

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Magister Scientiae Dentium - MSc(Dent)
BACKGROUND: Plaster models form an integral part of the traditional orthodontic records. They are necessary for diagnosis and treatment planning, case presentations as well as for the evaluation of treatment progress. The accuracy of the measurements taken for space assessment is crucial prior to treatment planning. The introduction of digital models overcomes some problems experienced with plaster models. Digital models have shown to be an acceptable alternative for plaster models. AIM: The aim of the study was to determine the accuracy of traditional measurement techniques when compared to the CAD/ CAM measurements in the assessment of tooth widths and arch perimeter from plaster models. METHOD: The mesio-distal tooth widths and arch perimeter of thirty archived plaster models were measured using a digital caliper to the nearest 0.01 mm and divider to the nearest 0.1 mm. Corresponding digital models were produced by scanning them with a CAD/CAM (InEos X5) and space analysis completed by measurements using InEos Blue software. Measurements were repeated after 1 week from the initial measurement. The methods were compared using descriptive analysis (mean difference and standard deviation). RESULTS: The operator reliability was high for digital models as well as the plaster models when the measurement tool was the digital caliper (analyzed using the Pearson correlation coefficient in the paired t-test). The mean values of tooth widths measurements of CAD/CAM, digital caliper and divider were 6.82 (±0.04), 6.94 (± 0.04) and 7.11 (± 0.04). There was a significant difference between the measurements made by the CAD/CAM and the divider. Additionally significant differences between the measurements by digital caliper and divider measurements (p < 0.05) were observed. No significant difference was found when comparing CAD/CAM to digital caliper. Positive correlation was displayed between CAD/CAM, digital caliper and the divider, but the measurements completed with the digital caliper had the highest correlation with the CAD/CAM. The difference was not significant between the aforementioned measurement tools (p > 0.05). Arch perimeter measurements showed no statistical significant difference between CAD/CAM, digital caliper and divider (p < 0.05). CONCLUSION: Archived plaster models stored as records can be converted to digital models as it will have the same accuracy of measurements. The value of doing a space analysis with the CAD/CAM system can be performed with similar reliability on the digital models as a caliper on plaster models.
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16

Roblee, Thomas, Robert R. Boyd, James Chen, and Heesoo Oh. "EFFICIENCY AND EFFECTIVENESS OF ARCH EXPANSION WITH CORTICOTOMY-ASSISTED CLEAR ALIGNER THERAPY." Scholarly Commons, 2020. https://scholarlycommons.pacific.edu/dugoni_etd/7.

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Introduction: Surgically Facilitated Orthodontic Therapy (SFOT) has been utilized for years to overcome the limitations encountered with traditional orthodontic treatment of dentoalveolar and alveoloskeletal malocclusions. The procedure, which consists of full flap corticotomies and bone grafting, has many proposed benefits including increased speed and range of tooth movement. The purpose of this study is to evaluate arch expansion in patients treated with SFOT and clear aligners. Materials and Methods: A retrospective cohort study design was used to evaluate 51 consecutive adult patients that were treatment planned for significant arch expansion with corticotomies, bone grafting, and clear aligners. 17 of the 51 patients refused the surgical procedure and served as controls. Eight transverse arch width measurements were obtained at three different time points (Initial, ClinCheck, Refinement). Five calculations were performed to determine the magnitude, predictability, and efficiency of arch expansion. Results: The difference in treatment time between the two groups was statistically significant at 5.2 months (P < .0001). On average, corticotomies reduced the length of treatment by 46% and increased the rate of expansion 2.4x. Patients that received SFOT achieved a greater magnitude (+28%) of expansion at a significantly higher rate (P< 0.002) than controls for all eight interarch measurements. The SFOT group displayed higher predictability (% goal achieved) and a smaller difference between predicted and achieved tooth movements for all measures obtained. The mean age for the entire sample was 42.81 (+12.51 years). Conclusion: Arch expansion with corticotomy-assisted clear aligner therapy is significantly more effective, efficient, and predictable than with clear aligners alone. The predictability of expansion with aligners appears to have a higher range than initially thought, even in patients that do not receive corticotomies.
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Bell, Eric Jason. "Arch variation in relatives of individuals with orofacial clefts using 3D dental casts." Thesis, University of Iowa, 2019. https://ir.uiowa.edu/etd/6704.

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Introduction: Dento-alveolar anomalies associated with Orofacial clefts (OFCs) can present with a wide range of variation. This vast diversity makes it difficult to pinpoint their specific etiology. For instance, differentiating anomalies that arise as a consequence of the physical effects of the cleft itself or from the same biological processes that result on clefting, from those that likely occur as a sequela from the surgical repair is a challenge. One approach that can aid this differentiation is to study if first degree relatives of children with clefts whom themselves do not have an overt cleft but may carry genetic cleft risk, are more likely to present some of these anomalies. If so, the elevated risk on these seemingly unaffected relatives will indicate that the particular anomaly arises as a consequence of the molecular pathways that give rise to cleft risk rather than from the physical consequences of the cleft or the surgical repairs. Understanding the different etiological factors underlying dental anomalies within the cleft phenotypic spectrum is a fundamental step for prevention and better management of such anomalies. Amongst the most common dento-alveolar anomalies seen in children born with OFC are tooth size-arch length discrepancies and dento-alveolar shape irregularities, mostly studied in the maxillary arches. Such arch irregularities lead to moderate or severe malocclusions. It is not well known if unaffected family members (UFM) of children with clefts are also susceptible to such dento-alveolar shape irregularities and thus their etiology is not well understood. This study aims to characterize 3D variation in dento-alveolar shape as part of the cleft phenotypic spectrum in UFMs of individuals with OFCs compared to controls with no history of OFC. Methods: A total of 760 maxillary and 760 mandibular casts were digitally scanned using a NextEngine Laser scanner and digitized by two raters with 92 landmarks for maxilla and 94 landmarks for mandible, covering gingival margins and occlusal surfaces via Landmark Editor Software. A reliability of 88.15% was obtained for an interrater agreement error of less than 1mm for all landmarks obtained. 3D coordinates were extracted and registered using a Procrustes fit procedure. Procrustes residuals were analyzed via canonical variate analyses to capture differences in 3D shape between cases and controls. Of the 760 maxillary individuals attempted, 535 (Cases N=133, Controls=402) had all 92 landmarks and 688 (Cases=192, Controls496) had at least 40 landmarks in the canine to canine region. Of the 760 mandibular individuals attempted, 434 (Cases N=99, Controls=335) had all 94 landmarks and 611 (Cases=180, Controls=431) had at least 40landmarks in the canine to canine region. Thus analyses were done separately for each subsample. Results: Case-control differences were not significant (P=0.11) for overall maxillary dental arch shape. However, for the maxillary canine to canine dataset, significant differences were found (P=0.02 for raw Procrustes distance, P<0.0001 for Mahalanobis distance). Case-control differences were significant (P=0.02) for overall mandibular dental arch shape. Significant shape differences were also found for the mandibular canine to canine dataset (P=0.01 for raw Procrustes distance, P<0.0001 for Mahalanobis distance). In other words, there is better separation between cases and controls for the mandibular dataset compared to the maxillary dataset (P=0.11 for the maxillary full arch). Cases had maxillary and mandibular anterior dentitions that were overall retrusive, with anterior teeth that significantly tapered towards the incisal third with larger interproximal incisal embrasures and height to width rations that deviate from ideal ratios (i.e. width is ~70% of the height) due to an overall decrease in crown height. Also, incisal edges seem to flare outwards from the arch line when compared to controls. Moreover, case arch forms trend towards a “v” shape, resembling a Bonwill-Hawley arch shape compared to a “u” shape in the controls. Conclusions: Upper anterior, lower anterior and overall arch shape significantly differ between UFM of individuals with OFC and controls. The most significant differences were located in the maxillary and mandibular anterior dentitions, where cases were more retrusive overall with incisal edges that were tapered and flared, displaying large embrasures and tapered and flared, displayed large embrasures when compared to controls. The phenotypic differences identified in this study contribute to the understanding of the cleft phenotypic spectrum aiding future studies of cleft etiology and cleft risk prediction.
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Padilla, Mark Thomas. "POSTURAL ADAPTATIONS IN ARCHWIRE EXPANSION WITH SELF-LIGATING BRACKETS." Master's thesis, Temple University Libraries, 2014. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/291479.

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Oral Biology
M.S.
Objectives: Orthodontic arch development expands and broadens the dentition beyond the confines of the original arch perimeter. This is often accomplished by means of self-ligating fixed appliances. When movements take the teeth outside those confines, without adoption, the muscular forces are unbalanced and may lead to dental relapse. Muscle spindles and associated reflex loops within the tongue provide feedback to arch perimeter changes that may produce postural changes to the new archform. Resting posture has long been accepted as aiding in tooth position. The objective of this study was to assess the oral and pharyngeal postural changes that result from arch development with the Damon system and report the amount of expansion accomplished. Methods: Pre- and post-treatment models and lateral cephalograms were collected on 69 previously treated orthodontic patients from four different private practices. Expansion was measured from the buccal cusp tips of the first and second premolars and first molars. A new cephalometric analysis was implemented to diagnose both variations in malocclusion and variations in posture of the head, neck, pharynx, hyoid bone and tongue. Results: Both tongue height and length increased, 2.9mm (P-value 0.001, SEM=1.06) and 3.76mm (P-value 0.00002, SEM=0.62) respectively, following posterior dental arch expansion using Damon archwires. Hyoid position was not significantly different. Conclusion: As dental arches are expanded the tongue increases in both length and height to fill the space and therefore may aid in stability during the retention phase of treatment. The lack of change in hyoid bone position, as one would expect with a rise in tongue position, might be explained by either slight changes in head position or the need to maintain the airway.
Temple University--Theses
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19

Tzenkov, Anton D. "Seismic analysis of concrete arch dams with contraction joint and nonlinear material models." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/MQ61026.pdf.

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20

Andersson, Andreas. "Capacity assessment of arch bridges with backfill : Case of the old Årsta railway bridge." Doctoral thesis, KTH, Bro- och stålbyggnad, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-32827.

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The work presented in this thesis comprises the assessment of existing arch bridges with overlying backfill. The main objective is to estimate the load carrying capacity in ultimate limit state analysis. A case study of the old Årsta railway bridge is presented, serving as both the initiation and a direct application of the present research. The demand from the bridge owner is to extend the service life of the bridge by 50 years and increase the allowable axle load from 22.5 to 25 metric tonnes. The performed analyses show a great scatter in estimated load carrying capacity, depending on a large number of parameters. One of the factors of main impact is the backfill material, which may result a significant increase in load carrying capacity due to the interaction with the arch barrel. Based on theoretical analyses, extensive conditional assessments and the demand from the bridge owner, it was decided that the bridge needed to be strengthened. The author, in close collaboration with both the bridge owner and the persons performing the conditional assessment, performed the development of a suitable strengthening. The analyses showed a pronounced three-dimensional behaviour, calling for a design using non-linear finite element methods. Due to demands on full operability during strengthening, a scheme was developed to attenuate any decrease in load carrying capacity. The strengthening was accepted by the bridge owner and is currently under construction. It is planned to be finalised in 2012. The application of field measurements to determine the structural manner of action under serviceability loads are presented and have shown to be successful. Measured strain of the arch barrel due to passing train has been performed, both before, during and after strengthening. The results serve as input for model calibration and verification of the developed strengthening methods. The interaction of the backfill was not readily verified on the studied bridge and the strengthening was based on the assumption that both the backfill and the spandrel walls contributed as dead weight only. The finite element models are benchmarked using available experimental results in the literature, comprising masonry arch bridges with backfill loaded until failure. Good agreement is generally found if accounting for full interaction with the backfill. Similarly, accounting for the backfill as dead weight only, often results in a decrease in load carrying capacity by a factor 2 to 3. Still, several factors show a high impact on the estimated load carrying capacity, of which many are difficult to accurately assess. This suggests a conservative approach, although partial interaction of the backfill may still increase the load carrying capacity significantly.
Arbetet i föreliggande avhandling omfattar analyser av befintliga bågbroar med ovanliggande fyllning. Huvudsyftet är att uppskatta bärförmågan i brottgränstillstånd. En fallstudie av gamla Årstabron redovisas, vilken utgör både initieringen och en direkt tillämpning av föreliggande forskning. Kravet från broförvaltaren är att öka brons livslängd med 50 år, samtidigt som axellasten ska ökas från nuvarande 22.5 ton till 25 ton. Utförda analyser visar på stor spridning i uppskattad bärförmåga, beroende på ett stort antal parametrar. En av de främsta faktorerna är fyllningens egenskaper, vilken kan resultera i en markant ökning av bärförmågan p.g.a. samverkan med bågen. Baserat på teoretiska analyser, tillståndsbedömningar och krav från broförvaltaren beslutades att bron skulle förstärkas. En förstärkningsmetod har utvecklats i nära samarbete med broförvaltaren och personer som tidigare utfört tillståndsbedömningarna. Analyserna visar ett utpräglat tredimensionellt beteende, vilket har föranlett användandet av icke-linjära finita elementmetoder. Krav på full trafik under samtliga förstärkningsarbeten har resulterat i att dessa utförs enligt en föreskriven ordning, som ska reducera minskning i bär­förmåga under samtliga etapper. Förstärkningsförslaget godkändes av Banverket och är för närvarande under byggnation. Enligt plan ska dessa slutföras under 2012. Fältmätningar har använts för att bestämma det statiska verkningssättet under brukslaster, vilket visas ge goda resultat. Resulterande töjningar från passerande tåg har uppmäts i bågen, både före, under och efter förstärkning. Resultaten har använts både för att kalibrera beräkningsmodeller och att verifiera utförda förstärkningar. Samverkan mellan båge och fyllning har inte kunnat verifierats för den aktuella bron och de utvecklade förstärkningarna baseras på en modell där både fyllning och sidomurar endast utgör yttre verkande last. De framtagna finita element modellerna har jämförts med experimentella resultat från litteraturen, omfattande tegelvalvsbroar med ovan­liggande fyllning belastade till brott. Generellt erhålls god överensstämmelse om full samverkan mellan båge och fyllning antas. Om fyllningen istället endast betraktas som yttre last, minskar lastkapaciteten ofta med en faktor 2 till 3. Fortfarande uppvisar ett antal faktorer stor inverkan på bärförmågan, vilka ofta är svåra att med säkerhet bestämma. Ett konservativt betraktningssätt rekommenderas, även om delvis sam­verkan med fyllningen fortfarande kan öka bärförmågan avsevärt.
QC 20110426
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21

Zeidan, Hala. "Detailed analysis of the transverse arch of hallux valgus feet with and without pain using weight-bearing ultrasound imaging and precise force sensors." Kyoto University, 2020. http://hdl.handle.net/2433/253224.

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付記する学位プログラム名: 充実した健康長寿社会を築く総合医療開発リーダー育成プログラム
Kyoto University (京都大学)
0048
新制・課程博士
博士(人間健康科学)
甲第22388号
人健博第74号
新制||人健||5(附属図書館)
京都大学大学院医学研究科人間健康科学系専攻
(主査)教授 黒木 裕士, 教授 高桑 徹也, 教授 妻木 範行
学位規則第4条第1項該当
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22

Maier, Georg [Verfasser]. "Smooth Minimum Arc Paths : Contour Approximation with Smooth Arc Splines / Georg Maier." Aachen : Shaker, 2010. http://d-nb.info/1084536501/34.

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23

Katsiampa, Paraskevi. "Nonlinear exponential autoregressive time series models with conditional heteroskedastic errors with applications to economics and finance." Thesis, Loughborough University, 2015. https://dspace.lboro.ac.uk/2134/18432.

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The analysis of time series has long been the subject of interest in different fields. For decades time series were analysed with linear models, which have many advantages. Nevertheless, an issue which has been raised is whether there exist other models that can explain and forecast real data better than linear ones. In this thesis, new nonlinear time series models are suggested, which consist of a nonlinear conditional mean model, such as an ExpAR or an Extended ExpAR, and a nonlinear conditional variance model, such as an ARCH or a GARCH. Since new models are introduced, simulated series of the new models are presented, as it is important in order to see what characteristics real data which could be explained by them should have. In addition, the models are applied to various stationary and nonstationary economic and financial time series and are compared to the classic AR-ARCH and AR-GARCH models, in terms of fitting and forecasting. It is shown that, although it is difficult to beat the AR-ARCH and AR-GARCH models, the ExpAR and Extended ExpAR models and their special cases, combined with conditional heteroscedastic errors, can be useful tools in fitting, describing and forecasting nonlinear behaviour in financial and economic time series, and can provide some improvement in terms of both fitting and forecasting compared to the AR-ARCH and AR-GARCH models.
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24

Ueda, Yuichi. "Retrograde Cerebral Perfusion with Hypothermic Circulatory Arrest in Aortic Arch Surgery : Operative and Long-Term Results." Nagoya University School of Medicine, 2001. http://hdl.handle.net/2237/5371.

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25

Glockner, Gregory D. "Dynamic network flow with uncertain arc capacities." Diss., Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/30734.

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26

Elmubarak, Mona. "Accuracy and reliability of traditional measurement techniques for tooth widths and arch perimeter compared to CAD/CAM." University of the Western Cape, 2018. http://hdl.handle.net/11394/6521.

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>Magister Scientiae - MSc
Background: Plaster models form an integral part of the traditional orthodontic records. They are necessary for diagnosis and treatment planning, case presentations as well as for the evaluation of treatment progress. The accuracy of the measurements taken for space assessment is crucial prior to treatment planning. The introduction of digital models overcomes some problems experienced with plaster models. Digital models have shown to be an acceptable alternative for plaster models. Aim: The aim of the study was to determine the accuracy of traditional measurement techniques when compared to the CAD/ CAM measurements in the assessment of tooth widths and arch perimeter from plaster models. Method: The mesio-distal tooth widths and arch perimeter of thirty archived plaster models were measured using a digital caliper to the nearest 0.01 mm and divider to the nearest 0.1 mm. Corresponding digital models were produced by scanning them with a CAD/CAM (InEos X5) and space analysis completed by measurements using InEos Blue software. Measurements were repeated after 1 week from the initial measurement. The methods were compared using descriptive analysis (mean difference and standard deviation). Results: The operator reliability was high for digital models as well as the plaster models when the measurement tool was the digital caliper (analyzed using the Pearson correlation coefficient in the paired t-test). The mean values of tooth widths measurements of CAD/CAM, digital caliper and divider were 6.82 (±0.04), 6.94 (± 0.04) and 7.11 (± 0.04). There was a significant difference between the measurements made by the CAD/CAM and the divider. Additionally significant differences between the measurements by digital caliper and divider measurements (p < 0.05) were observed. No significant difference was found when comparing CAD/CAM to digital caliper. Positive correlation was displayed between CAD/CAM, digital caliper and the divider, but the measurements completed with the digital caliper had the highest correlation with the CAD/CAM. The difference was not significant between the aforementioned measurement tools (p > 0.05). Arch perimeter measurements showed no statistical significant difference between CAD/CAM, digital caliper and divider (p < 0.05). Conclusion: Archived plaster models stored as records can be converted to digital models as it will have the same accuracy of measurements. The value of doing a space analysis with the CAD/CAM system can be performed with similar reliability on the digital models as a caliper on plaster models.
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27

Rodríguez, César. "Verification based on unfoldings of Petri nets with read arcs." Phd thesis, École normale supérieure de Cachan - ENS Cachan, 2013. http://tel.archives-ouvertes.fr/tel-00927064.

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Humans make mistakes, especially when faced to complex tasks, such as the construction of modern hardware or software. This thesis focuses on machine-assisted techniques to guarantee that computers behave correctly. Modern computer systems are large and complex. Automated formal verification stands as an alternative to testing or simulation to ensuring their reliability. It essentially proposes to employ computers to exhaustively check the system behavior. Unfortunately, automated verification suffers from the state-space explosion problem: even relatively small systems can reach a huge number of states. Using the right representation for the system behavior seems to be a key step to tackle the inherent complexity of the problems that automated verification solves. The verification of concurrent systems poses additional issues, as their analysis requires to evaluate, conceptually, all possible execution orders of their concurrent actions. Petri net unfoldings are a well-established verification technique for concurrent systems. They represent behavior by partial orders, which not only is natural but also efficient for automatic verification. This dissertation focuses on the verification of concurrent systems, employing Petri nets to formalize them, and studies two prominent verification techniques: model checking and fault diagnosis. We investigate the unfoldings of Petri nets extended with read arcs. The unfoldings of these so-called contextual nets seem to be a better representation for systems exhibiting concurrent read access to shared resources: they can be exponentially smaller than conventional unfoldings on these cases. Theoretical and practical contributions are made. We first study the construction of contextual unfoldings, introducing algorithms and data structures that enable their efficient computation. We integrate contextual unfoldings with merged processes, another representation of concurrent behavior that alleviates the explosion caused by non-determinism. The resulting structure, called contextual merged processes, is often orders of magnitude smaller than unfoldings, as we experimentally demonstrate. Next, we develop verification techniques based on unfoldings. We define SAT encodings for the reachability problem in contextual unfoldings, thus solving the problem of detecting cycles of asymmetric conflict. Also, an unfolding-based decision procedure for fault diagnosis under fairness constraints is presented, in this case only for conventional unfoldings. Finally, we implement our verification algorithms, aiming at producing a competitive model checker intended to handle realistic benchmarks. We subsequently evaluate our methods over a standard set of benchmarks and compare them with existing unfolding-based techniques. The experiments demonstrate that reachability checking based on contextual unfoldings outperforms existing techniques on a wide number of cases. This suggests that contextual unfoldings, and asymmetric event structures in general, have a rightful place in research on concurrency, also from an efficiency point of view.
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28

Bjurström, Henrik, and Johan Lasell. "Capacity assessment of a single span arch bridge with backfill : A case study of the Glomman Bridge." Thesis, KTH, Civil and Architectural Engineering, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-10065.

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The aim of this Master Thesis is to assess the load carrying capacity of the Glomman Bridge outside of the Swedish city Örebro. The Glomman Bridge is an unreinforced concrete single span arch bridge with backfill. The bridge was constructed in 1923 on assignment from the Swedish National Railways (SJ).

The failure criteria used in this thesis is that the bridge collapses when any cross section in the concrete arch reaches its ultimate capacity. In reality, the bridge may manage heavier loads than this. When the capacity is reached in a cross section, a hinge is formed and the arch relocates the forces to other parts of the arch that can carry higher stresses. The real bridge will not collapse until a fourth hinge is formed, and by that a mechanism. To be able to calculate the cross section forces in the arch, it was necessary to know the influences of the loads on the arch when they were run along the bridge. For this purpose, influence lines were obtained from a 2D finite element model created in ABAQUS, a general FE-analyses software. A calculation routine to find the least favourable load combination was then created in Matlab, a numerical calculation software. The routine was made to find the worst case among different load cases and to combine the standardized axle pressures with the present number of axles.

A parametric survey was also performed because the material properties for the different parts of the bridge are very uncertain. In the survey, the initial values were changed one at a time to study the outcome on the load factor. The load factor is the ratio between the ultimate limit load and the actual load. The studied parameters are the compressive strength, the Young's modulus, the density and the Poisson's ratio of the different parts of the bridge. The parameters are studied individually irrespective of possible correlation. The studied parts of the bridge are the backfill, the arch, the abutments and the asphalt. The clearly most important component is found to be the backfill. With increased stiffness or increased Poisson's ratio in the backfill follows increased load factor.

The equations behind the failure envelope can be derived from equilibrium equations for the unreinforced cross section. The influence lines are normalised with respect to the capacity of the cross section to get the degree of efficiency along the whole length of the arch, instead of the common influence lines that give the cross section forces. This is done because the failure is not caused by large cross section forces but by an exceeded ultimate stress. As the different loads are run along the bridge, the largest positive and negative efficiency for bending moment and normal force are localised. The normalised cross section forces are plotted together with the failure envelope and the load factor is then calculated.

Several masonry arch bridges were loaded until collapse in a study performed by the British Transport and Road Research Laboratory. One of the bridges in the study, the Prestwood Bridge, has been used in this thesis as a comparison to the Glomman Bridge. The load carrying capacity of the Prestwood Bridge is known, and is used to verify that the method using the failure envelope is applicable.

To compare the results from the cross section analysis from the failure envelope model to another method, the Glomman Bridge and the Prestwood Bridge were also tested in the commercial software RING 2.0. The method used in RING 2.0 differs from the failure mode in this thesis by calculating the load factor when four different cross sections reach their capacity and the bridge collapses.

The failure envelope method allows an A/B-value (Axle- and Bogie load) of 102 kN/147 kN when using very poor values of the parameters and 181 kN/226 kN when using a reference case with normal parameters.

Although the load capacity is found to be acceptable, the uncertainties are still large. To get a more accurate apprehension of the condition of the actual bridge, further research should be carried out, such as e.g. a non-linear model.


Syftet med föreliggande examensarbete är att uppskatta bärförmågan hos bron Glomman utanför Örebro. Glomman är en oarmerad betongvalvbro i ett spann med ovanliggande jordfyllning. Bron byggdes 1926 på uppdrag av Statens Järnvägar (SJ).

Brottkriteriet i detta examensarbete är att bron går till brott när något tvärsnitt i betongbågen uppnår sin kapacitet. I själva verket är det möjligt att bron kan klara tyngre last än detta. När kapaciteten nås i ett tvärsnitt uppstår en led och bågen omlagrar krafterna till andra bågdelar som klarar större spänningar. Den verkliga bron rasar inte förrän en fjärde led har utvecklats, och därmed en mekanism. För att kunna beräkna tvärsnittskrafterna i bågen, var det nödvändigt att känna till trafiklasternas påverkan på bågen när de kördes över bron. För detta ändamål erhölls influenslinjer från en tvådimensionell finita elementmodell skapad i ABAQUS, ett generellt FE-program. En beräkningsrutin för att finna värsta tänkbara lastkombinering skapades i Matlab, ett numeriskt beräkningsprogram. Rutinen utformades för att hitta värsta fallet bland olika lastfall samt för att kombinera standardiserade axeltryck med det aktuella antalet axlar.

En parameterstudie utfördes också då materialegenskaperna för de olika delarna i bron är mycket osäkra. I parameterstudien ändrades ingångsvärdena ett åt gången för att studera utslaget på lastfaktorn. Lastfaktorn är förhållandet mellan brottgränslasten och den verkliga lasten. De parametrar som studeras är tryckhållfastheten, E-modulen, densiteten och tvärkontraktionen för de olika brodelarna. Parametrarna studeras enskilt utan hänsyn till eventuell korrelation. De brodelar som studeras är fyllningen, bågen, fundamenten och asfalten. Den klart viktigaste komponenten visar sig vara fyllningen. Med ökad styvhet eller ökad tvärkontraktion i fyllningen följer ökad last­faktor.

Ekvationerna bakom brottenveloppet kan härledas ur jämviktsekvationer för det oarmerade tvärsnittet. Influenslinjerna normeras med avseende på tvärsnittets kapa­citet för att få ut utnyttjandegraden längs hela bågen. Detta görs då det egentligen inte är för stor tvärsnittskraft som orsakar brott utan för stor spänning. Högsta och lägsta utnyttjandegrad för böjande moment och normalkraft lokaliseras när de olika typlasterna körs över bron. Utnyttjandegraderna placeras i brottenveloppet för att sedan räkna fram en lastfaktor.

Ett flertal liknande broar har lastats till brott i en studie genomförd av British Transport and Road Research Laboratory. En av broarna i studien, Prestwood Bridge, har använts i denna rapport som jämförelse med Glomman. Då bärförmågan hos Prestwood Bridge är känd används den till att bekräfta att metoden med brott­enveloppet är tillämpbar.

För att jämföra resultaten från tvärsnittsanalysen i brottenveloppmetoden med en annan metod, testades även Glomman och Prestwood Bridge i det kommersiella programmet RING 2.0. Metoden som används i RING 2.0 skiljer sig från brottmoden i denna rapport genom att istället beräkna lastfaktorn när fyra olika tvärsnitt har uppnått sina kapaciteter och bron kollapsar.

Metoden med brottenvelopp tillåter ett A/B-värde (Axel- och Boggitryck) på 102 kN/147 kN när mycket dåliga parametervärden används och 181 kN/226 kN när referensfallet med normala parametervärden används.

Även om bärförmågan kan anses vara acceptabel är osäkerheterna stora. För att få en nogrannare uppfattning om brons faktiska tillstånd bör fortsatta studier utföras, som t.ex. en icke-linjär modell.

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29

Fleming, Padhraig Seamus. "An assessment of arch dimensional change with self-ligating brackets : systematic review and a randomised controlled trial." Thesis, Queen Mary, University of London, 2013. http://qmro.qmul.ac.uk/xmlui/handle/123456789/8718.

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The purposes of this study were to systematically review the evidence on the clinical use of self-ligating brackets (SLBs) and the validity of digital models, and to compare maxillary arch dimensional change during alignment with conventional brackets (CBs) and active or passive self-ligation in a clinical study. In the systematic reviews, multiple databases were searched, study selection, quality assessment and data extraction were performed, and meta-analyses conducted, where appropriate. In a laboratory study a technique to measure molar inclination change incorporating digital models was developed and validated. A multicentre, 3- arm parallel-group trial was conducted with 96 patients aged 16 and above randomly allocated into 3 equal groups (OvationTM, InOvationCTM or Damon QTM) and undergoing alignment with a DamonTM wire sequence for at least 34 weeks. Meta-analyses demonstrated no difference in arch dimensional changes between SLBs and CBs; however, a greater treatment time was found with self-ligation (2.2 months, 95% CI: 0.4, 3.98). The validity of direct measurement on digital models was confirmed in the other review, although meta-analysis was not possible. Complete data were obtained from 87 subjects in the trial. Bracket type had no significant effect on transverse dimensional changes with no difference in inter-molar width between passive self-ligation and CBs (0.32mm, 95% CI: -0.41, 1.05, p= 0.38) or active selfligation (0.4mm, 95% CI: -0.31, 1.11, p= 0.27). Incisor inclination changes with Damon QTM could not be differentiated from the conventional system (0.44 degrees, 95% CI: - 1.93, 2.8, p=0.71) or InOvationCTM (-0.22 degrees, 95% CI: -2.58, 2.14, p=0.85). Based on the systematic reviews, measurement of digital models is a valid alternative to plaster models, while little evidence to support the use of self-ligation was found. In the clinical trial no differences in arch dimensional changes during alignment between CBs and either active or passive self-ligation was found.
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30

Gutiérrez, Faxas Patricia. "Distributed Constraint Optimization Related with Soft Arc Consistency." Doctoral thesis, Universitat Autònoma de Barcelona, 2012. http://hdl.handle.net/10803/98395.

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Los Problemas de Optimización con Restricciones Distribuidos (DCOP) son utilizados para modelar problemas de coordinación multi-agente. Los DCOPs se definen con un número finito de agentes, variables y funciones de coste. El objetivo es encontrar una asignación de todas las variables cuyo coste global sea mínimo. Para lograrlo, los agentes que manejan las variables han de intercambiar información sobre el coste de sus asignaciones hasta encontrar la solución óptima. Varios algoritmos distribuidos se han propuesto para encontrar soluciones óptimas en DCOPs. En el caso centralizado, se han desarrollado técnicas para acelerar la resolución de problemas de optimización con restricciones. En particular, técnicas de arco consistencia blanda, como AC, FDAC y EDAC, las cuales identifican valores inconsistentes que pueden ser eliminados. El objetivo de esta tesis es incluir técnicas de arco consistencia blanda en la resolución de DCOPs. Esta combinación obtiene mejoras sustanciales en el rendimiento. Las arco consistencias blandas son conceptualmente iguales en el caso centralizado y distribuido. Sin embargo, mantenerlas en el caso distribuido requiere un enfoque diferente. En centralizado, todos los elementos del problema están disponibles para el único agente que realiza la búsqueda, mientras que en el caso distribuido los agentes solo conocen algunas partes del problema y deben intercambiar información para lograr el nivel de consistencia deseado. En este proceso, las estructuras del problema se deben modificar de tal manera que la información parcial del problema global permanezca coherente en cada agente. En esta tesis presentamos tres contribuciones para la resolución de DCOPs. En primer lugar, hemos estudiado el algoritmo de búsqueda BnB-ADOPT y hemos podido mejorarlo de manera significativa. Probamos que algunos de los mensajes enviados por BnB-ADOPT son redundantes y pueden ser eliminados sin afectar la optimalidad y completitud del algoritmo. Además, cuando se trabaja con restricciones de aridad mayor que dos, algunos problemas aparecen en este algoritmo. Proponemos una forma simple de solucionarlos obteniendo una nueva versión para el caso n-ario. También, presentamos el nuevo algoritmo ADOPT(k), el cual generaliza los algoritmos ADOPT y BnB-ADOPT. ADOPT(k) realiza una estrategia de búsqueda similar a ADOPT, a BnB-ADOPT, o a un híbrido de ambos dependiendo del parámetro k. En segundo lugar, introducimos técnicas de arco consistencia blanda en DCOPs, utilizando BnB-ADOPT+ como algoritmo de resolución. Durante la búsqueda mantenemos los niveles de consistencia AC y FDAC, con la limitación que solo se propagan borrados incondicionales, logrando importantes beneficios en la comunicación y en esfuerzo de cómputo. Mantenemos FDAC en varios órdenes de las variables obteniendo reducciones en la comunicación. Además, proponemos DAC por propagación de token, una nueva forma de propagar borrados durante la búsqueda distribuida. Experimentalmente, esta estrategia ha demostrado ser competitiva comparada con FDAC. En tercer lugar, exploramos la inclusión de restricciones globales blandas en DCOPs. Pensamos que las restricciones globales mejoran la expresividad de DCOP. Proponemos tres formas de incluir restricciones globales blandas en DCOP y extendemos el algoritmo BnB-ADOPT+ para incorporarlas. Además, exploramos el impacto de mantener arco consistencia en problemas con restricciones globales blandas. Experimentalmente, medimos la eficiencia de los algoritmos propuestos en varios conjuntos de datos comúnmente usados en la comunidad de DCOP.
Distributed Constraint Optimization Problems (DCOPs) can be used for modeling many multi-agent coordination problems. DCOPs involve a finite number of agents, variables and cost functions. The goal is to find a complete variable assignment with minimum global cost. This is achieved among several agents handling the variables and exchanging information about their cost evaluation until an optimal solution is found. Recently, researchers have proposed several distributed algorithms to optimally solve DCOPs. In the centralized case, techniques have been developed to speed up constraint optimization solving. In particular, search can be improved by enforcing soft arc consistency, which identifies inconsistent values that can be removed from the problem. Some soft consistency levels proposed are AC, FDAC and EDAC. The goal of this thesis is to include soft arc consistency techniques in DCOP resolution. We show that this combination causes substantial improvements in performance. Soft arc consistencies are conceptually equal in the centralized and distributed cases. However, maintaining soft arc consistencies in the distributed case requires a different approach. While in the centralize case all problem elements are available in the single agent performing the search, in the distributed case agents only knows some part of the problem and they must exchange information to achieve the desired consistency level. In this process, the operations that modify the problem structures should be done in such a way that partial information of the global problem remains coherent on every agent. In this thesis we present three main contributions to optimal DCOP solving. First, we have studied and experimented with the complete solving algorithm BnB-ADOPT. As result of this work, we have improved it to a large extent. We show that some of BnB-ADOPT messages are redundant and can be removed without compromising optimality and termination. Also, when dealing with cost functions of arity higher than two, some issues appear in this algorithm. We propose a simple way to overcome them obtaining a new version for the n-ary case. In addition, we present the new algorithm ADOPT($k$), which generalizes the algoritms ADOPT and BnB-ADOPT. ADOPT ($k$) can perform a search strategy either like ADOPT, like BnB-ADOPT or like a hybrid of both depending on the $k$ parameter. Second, we have introduced soft arc consistency techniques in DCOPs, taking BnB-ADOPT$^+$ as our base solving algorithm. During the search process, we enforce the soft arc consistency levels AC and FDAC, under the limitation that only unconditional deletions are propagated, obtaining important benefits in communication and computation. We enforce FDAC considering multiple orderings of the variables obtaining savings in communication. Also, we propose DAC by token passing, a new way to propagate deletions during distributed search. Experimentally, this strategy turned out to be competitive when compared to FDAC. Third, we explore the inclusion of soft global constraints in DCOPs. We believe that soft global constraints enhance DCOP expressivity. We propose three different ways to include soft global constraints in DCOPs and extend the solving algorithm BnB-ADOPT$^+$ to support them. In addition, we explore the impact of soft arc consistency maintenance in problems with soft global constrains. Experimentally, we measure the efficiency of the proposed algorithms in several benchmarks commonly used in the DCOP community.
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31

Xing, Aitang. "Dosimetric Investigation of Electron Arc Therapy Delivered Using Siemens Electron Arc Applicator with a Trapezoidal Aperture." Thesis, University of Canterbury. Physics and Astronomy, 2007. http://hdl.handle.net/10092/1486.

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This study investigated the delivery of electron arc treatment with a trapezoidal aperture. The aim of the investigation is to reduce the nonuniformity of the dose distribution, which is caused by the variation of the patient contour from superior to inferior. The characteristics of static electron beam were first investigated. Then a measurement-based algorithm was developed and implemented as a computer program called EarcMU to calculate the monitor units required for delivering the prescribed dose with a trapezoidal aperture. The central axis percentage depth dose was found to be independent of source-to-surface distance (SSD) and the width of the aperture. The inplane profiles of a trapezoidal aperture show that the dose decreases longitudinally from the wide to the narrow end of the trapezoidal aperture. The EarcMU program was verified using two cylindrical water phantoms. The measured dose and the dose calculated by the program agreed within 2.1% in the typical clinical conditions. A simple method was also proposed for determining the trapezoidal aperture for an individual patient. Under the same conditions, the trapezoidal apertures calculated by this method along with the open aperture were used to deliver treatments to several conical phantoms. Significant improvement in the uniformity of dose distribution was observed. On average, the flatness index of the longitudinal dose distribution from superior to inferior decreases dramatically from 8% for open aperture down to 0.58% for trapezoidal aperture. The results are clinically significant, indicating that delivering the electron arc treatment using a trapezoidal aperture can bring more uniform dose to the patient regardless of the change of patient contour from superior to inferior.
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Jorge, Paula Karine. "Evaluation of the dental arch in children with cleft lip and palate by means of 3D digital models." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/61/61132/tde-14012015-103434/.

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The aim of this study was to evaluate the dimensional alterations of dental arches of cleft lip and palate children after cheiloplasty at two rehabilitation centers. The sample was composed of 94 digital models and divided in two groups: Group I 23 children, assisted at University of Zurich with presurgical orthopedic intervention (Hotz plate); Group II 24 children, assisted at Hospital for Rehabilitation of Craniofacial Anomalies of the University of São Paulo without presurgical orthopedic intervention. The three dimensional images were used to evaluate before lip repair (stage 1) and approximately 1 year old (stage 2). The obtained measures were: intercanine distance, intertuberosity distance, anterior-posterior arch distance, anterior-posterior cleft length, anterior and posterior cleft width. The comparison between stages 1 and 2 was evaluated in group I, group II and between group I and II. The alterations between groups were verified by Independent t test. If the sample did not present a normal distribution, Wilcoxon and Mann-Whitney tests were used. In Group I, the comparisons between stages 1 and 2 showed that the intertuberosity and anterior-posterior arch distance increased and the intercanine, anterior and posterior cleft distances decreased. In Group II, the comparisons between stages 1 and 2 showed that intertuberosity distance increased and intercanine, anteriorposterior cleft length distances, anterior and posterior cleft widths decreased. The comparison of the dimensional alterations of dental arches between the two rehabilitation centers exhibited differences: in the stage 1, the intercanine distance decreased in Group II; in the stage 2, the anterior cleft width, the intercanine distance and the anterior-posterior cleft length decreased in Group II, suggesting the superposition of maxillary segments; in Group II, there was a greater narrowing of the anterior and posterior cleft widths, suggesting that Hotz plate induced a more evenly and equidistant approximation of maxillary segments in Group I. It is worth emphasizing that more studies should be conduct to reduce the variability in treatment protocols for cleft lip and palate patients, thus assuring the best evidencebased treatment.
O propósito deste estudo foi avaliar as alterações dimensionais dos arcos dentários de crianças com fissura de lábio e palato após a queiloplastia em dois centros de reabilitação. A amostra foi composta por 94 imagens digitais de modelos de gesso, e dividida em dois grupos: Grupo I - 23 crianças, tratas na Universidade de Zurique, com intervenção ortopédica pré-cirúrigica (placa de Holtz); Grupo II - 24 crianças tratadas no Hospital de Reabilitação de Anomalias Craniofaciais da Universidade de São Paulo, sem intervenção ortopédica pré-cirúrgica. As imagens tridimensionais dos modelos de gesso foram avaliados antes da queiloplastia (estágio 1) e com aproximadamente 1 ano de idade (estágio 2). As seguintes dimensões foram obtidas: comprimento anteroposterior da fissura, amplitude anterior da fissura, amplitude posterior da fissura, comprimento anteroposterior do arco, distância intercaninos e distância intertuberosidades. As comparações foram realizadas entre os estágios 1 e 2 e entre os grupos I e II. As diferenças entre os grupos foram verificadas pelo teste t independente, os testes de Wilcoxon e Mann-Whitney foram usados. No Grupo I, entre os estágios 1 e 2, as distâncias intertuberosidade aumentou e as distâncias intercaninos, distância anteroposterior da fissura, amplitude anterior e posterior da fissura diminuíram. A comparação entre as alterações dimensionais dos arcos dentários entre os dois centros de reabilitação apresentaram diferenças: no estágio 1, a distância intercaninos foi menor no Grupo II que no Grupo I; e no estágio 2, a amplitude anterior da fissura, a distância intercaninos e o comprimento anteroposterior da fissura foram menos no Grupo II que no Grupo I, sugerindo sobreposição dos segmentos maxilares. No Grupo II, houve maior estreitamento nas amplitudes anterior e posterior da fissura, sugerindo que a placa de Holtz no Grupo I induziu a aproximação dos segmentos maxilares de forma mais uniforme e equidistante. É importante salientar que mais estudos longitudinais precisam ser conduzidos a fim de reduzir a variabilidade de protocolos de tratamento em pacientes com fissura de lábio e palato, garantindo o melhor tratamento baseado em evidências científicas.
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Ocker, Stella Koch. "Testing the Production of Scintillation Arcs with the Pulsar B1133+16." Oberlin College Honors Theses / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=oberlin1526565414057674.

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Rowley, Iain. "Midwife of An-arché : toward a poetics of becoming-with-woman." Thesis, University of East Anglia, 2014. https://ueaeprints.uea.ac.uk/56847/.

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This project explores the connections between midwifery and the ethical demands attendant to poetic practice. Through verse and prose, I unfold a figuration of the midwife that traverses the boundaries between Levinasian heteronomy and Deleuzian heteromorphism, and is a constitutive factor in sites of resistance to the biomedical territorialisation of the creative body. Chief archival and methodological components that inform the thesis include: a historiography of childbirth - tracing the development of ‘holistic’ and ‘interventionist’ paradigms, and the ideological underpinnings of the phallocratic takeover of the birthing room in certain Western countries; idiographic insights gathered from dialogues with maternal practitioners and mothers, including residents of The Farm in Tennessee - where I participated in a midwifery workshop week; an experiential inquiry into Holotropic Breathwork - to facilitate access to non-ordinary states of consciousness; and a negotiation between Marxist-feminist and poststructuralist articulations of ethico-political agency. Subject matter ranges from a consideration of the ethical import of the placental economy to the bio-intelligent tissue of the psoas, the banishment of Anne Hutchinson from Massachusetts Bay to the legacy of the ‘Twilight Sleep’ movement. Sustained critical attention is devoted to Mina Loy’s “Parturition”, and contemporary poets that have acknowledged Loy as an influence, such as Lara Glenum. I suggest that, despite the absence of a birth attendant on the symbolic level, Loy’s poem resonates with the investments of midwifery, instating a ‘subjectin- process’ that woks through and against abstruse and instrumental discourses, defying both the technocratic erasure of maternal knowing and the fetishistic reduction of labour to an end-product. Art’s capacity for opening up a corporeallycharged zone of between-ness is further elaborated in an essay on Andrei Tarkovsky’s Stalker - through which the treatment of spatiotemporality is aligned with the imperatives of midwifery guardianship.
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35

Arzpeyma, Niloofar. "Modeling of electric arc furnaces (EAF) with electromagnetic stirring." Thesis, KTH, Materialvetenskap, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-43906.

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The influence of electromagnetic stirring in an electric arc furnace (EAF) has been studied. Using numerical modeling the effect of electromagnetic stirring on the thermal stratification and fluid flow has been investigated. The finite element method (FEM) software was used to compute the electromagnetic forces, and the fluid flow and heat and mass transfer equations were solved using a finite volume method (FVM) software. The results show that electromagnetic stirring has a significant effect on temperature homogenization and mixing efficiency in the bath. The important part of this study was calculation of heat transfer coefficient. The results show, electromagnetic stirring improves the heat transfer from the melt to scrap which is dependent on the stirring direction and force magnitudes.
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Li, Rong Ding 1967. "Dynamic electron arc therapy with the Clinac-21EX linac." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=101603.

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Electron arc therapy is the treatment modality for superficial tumors involving large curved surfaces. At the McGill University Health Centre, the characteristic angle beta concept was developed for the dosimetry and treatment planning of electron arc therapy. In this work, this concept was verified in dynamic mode with the new generation linac of Varian(TM), the Clinac-21 EX.
Radial PDDs were measured for beta angles varying from 60º--120º of electron arc beams with energies of 6 MeV, 9 MeV, and 12 MeV and 2-D isodose distributions of electron arc beams were studied as well. Dose penumbral regions exist at the beam start area and stop area, and the size of these regions is a function of the beam energy and the field width. When shielded with a tertiary collimator, the size of the penumbral regions and the dose levels in the penumbral regions were reduced significantly, and it is sufficient for the shielding to cover exactly the start field and the stop field of the arc beam in a clinical setting.
The dose rate of the electron arc beam was investigated. It was found that the dose rate at the depth of dose maximum linearly increased with the arc beam field width and was independent of the arc angle.
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37

Marghitu, Octav. "Auroral arc electrodynamics with FAST satellite and optical data." [S.l.] : [s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=967869188.

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38

Zeytun, Serkan. "Stochastic Volatility, A New Approach For Vasicek Model With Stochastic Volatility." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/3/12606561/index.pdf.

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In the original Vasicek model interest rates are calculated assuming that volatility remains constant over the period of analysis. In this study, we constructed a stochastic volatility model for interest rates. In our model we assumed not only that interest rate process but also the volatility process for interest rates follows the mean-reverting Vasicek model. We derived the density function for the stochastic element of the interest rate process and reduced this density function to a series form. The parameters of our model were estimated by using the method of moments. Finally, we tested the performance of our model using the data of interest rates in Turkey.
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39

Ayub, Priscila Vaz. "Analysis of the maxillary dental arch after rapid maxillary expansion in patients with unilateral complete cleft lip and palate." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/61/61132/tde-14012015-094508/.

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Objective: The aim of this study was to evaluate the dentoalveolar effects of rapid maxillary expansion in children with unilateral complete cleft lip and palate in comparison with non-cleft patients. Methods: The experimental group (EG) was composed of 25 patients with unilateral and complete cleft lip and palate (9 males and 15 females) with a mean age of 10.6 years. The control group (CG) comprised of 27 patients without cleft lip and palate (14 males and 13 females) with a mean age of 9.1 years. Dental models of the maxillary dental arch were obtained immediately preexpansion (T1) and 6 months post-expansion (T2) at the time of appliance removal. Digital dental models were obtained using the 3Shape R700 3D laser scanner (3Shape A/S, Copenhagen, Denmark). Transversal widths, arch perimeter, arch length, palatal depth, palatal volume, canine and posterior tooth inclination were digitally measured. Paired t-test was used to perform interphase comparisons and independent t-test to perform intergroup comparisons (p<0.05). Results: In the experimental group, the expansion produced a ignificant increase of all maxillary transverse measurements, palatal volume, arch perimeter and palatal depth while decreased the arch length. RME caused a buccal tip of posterior teeth in patients with UCLP. No differences were observed between experimental and control groups for all the measurements performed except for the intermolar distance (6-6), which showed a greater increase in patients with cleft. Conclusion: Rapid maxillary expansion showed similar dentoalveolar effects in children with UCLP and without oral clefts.
Objective: The aim of this study was to evaluate the dentoalveolar effects of rapid maxillary expansion in children with unilateral complete cleft lip and palate in comparison with non-cleft patients. Methods: The experimental group (EG) was composed of 25 patients with unilateral and complete cleft lip and palate (9 males and 15 females) with a mean age of 10.6 years. The control group (CG) comprised of 27 patients without cleft lip and palate (14 males and 13 females) with a mean age of 9.1 years. Dental models of the maxillary dental arch were obtained immediately preexpansion (T1) and 6 months post-expansion (T2) at the time of appliance removal. Digital dental models were obtained using the 3Shape R700 3D laser scanner (3Shape A/S, Copenhagen, Denmark). Transversal widths, arch perimeter, arch length, palatal depth, palatal volume, canine and posterior tooth inclination were digitally measured. Paired t-test was used to perform interphase comparisons and independent t-test to perform intergroup comparisons (p<0.05). Results: In the experimental group, the expansion produced a ignificant increase of all maxillary transverse measurements, palatal volume, arch perimeter and palatal depth while decreased the arch length. RME caused a buccal tip of posterior teeth in patients with UCLP. No differences were observed between experimental and control groups for all the measurements performed except for the intermolar distance (6-6), which showed a greater increase in patients with cleft. Conclusion: Rapid maxillary expansion showed similar dentoalveolar effects in children with UCLP and without oral clefts.
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40

Wright, Mark. "Probing the star-formed region W3(OH) with ground-state hydroxyl masers." Thesis, University of Bristol, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340298.

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41

Eivensitz, Ran. "A QUANTITATIVE ANALYSIS OF PATIENTS WITH POSSIBLE AUGMENTED RENAL CLEARANCE AND ITS RELEVANCE TO PREDOMINANTLY RENALLY EXCRETED DRUGS." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2014. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2014~D_20140618_233713-04964.

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Objective of work: the aim of this study was to conduct a retrospective, quantitative, descriptive survey accompanied with a comparative statistical research, in which cases of patients with augmented renal clearance were examined and analyzed regarding the similarities and differences between them and their relevance for possible under-dosage of predominantly renally excreted drugs. Tasks: 1. to detect all cases of lower than 50 µmol/L Scr measurements and calculate possible ARC using Cockcroft-Gault equation in a defined period of time in a Lithuanian hospital in Kaunas. 2. To compare the performance of 3 different equations to distinguish the ARC as assessed by Cockcroft-Gault equation from non-ARC cases. 3. To analyze possible reasons associated with these ARC cases. 4. To search for the cases when predominantly renally excreted drugs were prescribed to these patients.
Tikslas darbo: Šio tyrimo tikslas buvo atlikti a posteriori, kiekybinį aprašomąjį tyrimą Kartu su lyginamosios statistinių tyrimų, kuriais atvejais pacientai, sergantys inkstų papildyta klirensas buvo išnagrinėti ir išanalizuoti apie panašumus ir skirtumus tarp jų ir jų svarbą galimo nepakankamo dozę daugiausia išsiskiria pro inkstus narkotikų. Uždaviniai: 1. Aptikti bet mažesnis negu 50 mmol / l SCR matavimų bylas ir apskaičiuoti galimą ARC naudojant Kokrofto-Gault lygtis nustatytą laiką, Lietuvos ligoninę Kaune. 2. Norėdami palyginti iš 3 skirtingų lygčių atskirti ARC, įvertintas Kokrofto-Gault lygtį kokybės iš ne ARC atvejais. 3. Išanalizuoti galimas priežastis, susijusias su šių ARC atvejais. 4. Norėdami ieškoti atvejai, kai daugiausia išsiskiria pro inkstus narkotikų buvo nustatyta, kad šiems pacientams.
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42

Niaouris, Apostolos. "An algebra of Petri nets with arc-based timing restrictions." Thesis, University of Newcastle Upon Tyne, 2006. http://hdl.handle.net/10443/1999.

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Human beings from the moment they understood the power of their brain tried to create things to make their life easier and satisfy their needs either physical or mental. Inventions became more and more complicated, covering almost every aspect of human life and satisfying the never ending human curiosity. One of the reasons for this complexity is that an increasing number of systems exhibit concurrency. The development of concurrent systems is generally challenging since it is more difficult to fully understand their exact behaviour. In this thesis We present and investigate two of the most widely used and well studied theories to capture concurrent behaviour. Based on the results of PBC, we develop two algebras, one based on term re-writing and the other on Petri nets, aimed at the Specification and analysis of concurrent systems with timing information. The former is based on process expressions (at-expressions) and employs a set of SOS rules providing their operational semantics. The latter is based on a class of Petri nets with time restrictions associated with their arcs, called at-boxes, and the corresponding transition firing rule. We relate the two algebras through a compositionally defined mapping which for a given at-expression returns an at- box with behaviourally equivalent transition system. The resulting framework consisting of the two algebras is called the Timed-Arc Petri Box Calculus, or atPBC.
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43

Chhowalla, Manish. "Carbon thin films with enhanced properties from cathodic arc plasmas." Thesis, University of Cambridge, 1998. https://www.repository.cam.ac.uk/handle/1810/265423.

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In this thesis, the physical, optical and electronic properties of amorphous carbon ( a-C) thin films deposited using a filtered and unfiltered cathodic arcs are investigated. Firstly, the plasma properties of the filtered cathodic vacuum arc (FCVA) have been examined using planar and wire Langmuir probes in order to optimize the plasma throughput around the 90� bend. The knowledge of plasma characteristics is then utilized to understand the properties of highly tetrahedral amorphous carbon ( ta-C) films as a function of the ion energy, deposition temperature and the deposition rate. A model based on the intrinsic thermal effects of the deposition process is developed to explain the discrepancy of the sp3 fraction versus the ion energy in the literature. The possibility of p-type electronic doping of ta-C has also been investigated by the incorporation of B into the ta-C matrix. It was shown for the first time that the incorporation of B in ta-C reduces the compressive stress while maintaining high sp3 bonding. The details of a new form of arc discharge referred to as the 'stationary arc' which allows the deposition of smooth ta-C films without a bulky macroparticle filter are reported. Finally, extraordinary hardness and elastic properties of a new form of carbon arising from interlinking of graphitic nanoparticles are also presented.
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44

Hill, S. D. "Plasma torch interaction with a melting substrate." Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/17261.

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45

Luka, Miral. "Spiritual transformation in persons with developmental disabilities in l'Arche community koinonia as a vehicle for metanoia /." Theological Research Exchange Network (TREN), 2005. http://www.tren.com/search.cfm?p088-0131.

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46

Christman, Benjamin M. "Evaluation of frictional forces between brackets of different types at various angulations and an arch wire: With and without pulsating vibration." Thesis, NSUWorks, 2015. https://nsuworks.nova.edu/hpd_cdm_stuetd/61.

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Objective: The objective of this study was to determine the effect of pulsating vibration on the sliding resistance between orthodontic brackets and stainless steel wires. Brackets were placed at two different angulations (0° and 5°) to simulate leveling of a tipped tooth during tooth movement. Pulsating vibration was delivered via the AcceleDent device. Background: Friction is defined as a force that retards or resists the relative motion of two objects in contact, and its direction is tangential to the common boundary of the two surfaces in contact. This has been of interest to the orthodontist since the mid-20th century. Since the time of Stoner’s paper in 1960, the orthodontic literature has been full of studies done on friction in orthodontics including: friction with different ligation methods, friction among different arch wire materials, friction and different bracket materials, and friction with various slot designs. Understanding friction has led to the emergence of new technologies in orthodontics. One of the most popular is the self-ligating bracket. This popularity arose from claims that they reduce friction during treatment. Other innovations have been introduced in the field of orthodontics to help accelerate tooth movement. Among these innovations is the application of a pulsating vibration during active orthodontic treatment. Such pulsating vibration can be delivered during orthodontic treatment by AcceleDent, which is a hands- free device designed by OrthoAccel Technologies, Inc., Bellaire, TX. The company claims the output force helps accelerate bone turnover. The following study investigated whether it could decrease treatment time via a different mechanism: decreasing frictional resistance to tooth movement along the arch wire. Methods: A paper template was made of a typodont tooth with a bracket window cut out. The bracket cut out was made with the bracket window angulated 0° and 5°. 0.022” x 0.028” standard prescription edgewise brackets (American Orthodontics, Sheboygan, WI) of ceramic, twin and self-ligating design were bonded to 3 maxillary 1st premolar typodont teeth using the template. The teeth were leveled with a 0.019” x 0.025” SS arch wire and placed in a metal scaffold. They were held in place with Aquasil Ultra XLV wash material PVS (DENTSPLY Caulk, Milford, DE.). Only the middle bracket was adjusted for angulation and accuracy was checked with the iPhone 6 level. The AcceleDent Aura device (OrthoAccel Technologies, Inc., Bellaire, TX). was attached to the occlusal surface of the teeth via cable ties. The AcceleDent Aura device provided 30 Hz of pulsating vibration. All tests were performed with a 0.019” x 0.025” SS arch wire pulled through the brackets via a Universal Testing Machine (Instron, Grove City, PA) at a crosshead speed of 2.5mm/min for 30 seconds. Frictional resistance was measured by averaging 6 recordings every 5 seconds. Results: The pulsating vibration provided by the AcceleDent device significantly reduced the resistance to sliding for each bracket type at both 0° and 5° (p<0.05). Ceramic brackets had the highest resistance to sliding of all bracket types. Conclusions: Pulsating vibration via the AcceleDent Aura device reduces the resistance to sliding between a bracket and arch wire in vitro. This may potentially decrease overall treatment time but more in vivo studies need to be done to evaluate this.
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Almulla, Muhannad. "Implementation of an Arc Model for MV Network with Resonance Earthing." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-278499.

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The most common fault type in electric power systems is the line to groundfault. In this type of faults, an electrical arc is usually developed. The thesispresents a mathematical model that describes the behavior of the arc during afault. The arc model has been verified based on real and simulated tests thatwere conducted on a system that has resonant earthing coil.In addition, two studies have been conducted on the same verified system.The first studied was implemented to see the effect of detuning the resonantearthing coil at different levels. It was noted that detuning the coil affected ACand the DC components in the arc faults. Also, the detuning affected the arcextinction.The second study has been looking at the effects of implementing a parallelresistor to the resonant earthing coil. The tests have been conducted usingdifferent set values of the resistor. In some of the studied cases and during thetesting period, the resistor has affected the self-extinguish behavior of the arc.
Den vanligaste feltypen i elektriska kraftsystem är fas till jord. I denna typ avfel utvecklas vanligtvis en elektrisk ljusbåge. Examensarbetet presenterar enmatematisk modell som beskriver ljusbågens beteende under ett fel. Bågmodellenhar verifierats baserat på verkliga tester och simuleringar som utfördespå ett system som har resonansjordningsspole.Dessutom har två studier genomförts på samma verifierade system. Denförsta studien genomfördes för att se effekten av avstämning av den resonantajordningspolen på olika nivåer. Det noterades att avstämning av spolen påverkadeACoch DC-komponenterna i ljusbågsfel.Avstämningen påverkade ocksåljusbågens släckning.Den andra studien har tittat på effekterna av att implementera ett parallelltmotstånd till den resonanta jordningsspolen. Testen har utförts med olikainställda värden på motståndet. I några av de studerade fallen och under testperiodenhar motståndet påverkat ljusbågens självsläckande beteende.
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48

Tan, Benjamin H. "A Novel Arc Welding Power Supply with Improved Power Factor Correction." DigitalCommons@CalPoly, 2020. https://digitalcommons.calpoly.edu/theses/2199.

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This paper presents the design and development of a novel Arc Welding Power Supply utilizing a modified two-switch forward converter topology. The proposed design improves the power quality by improving power factor to near unity and reducing total harmonic distortion. State space analysis of the proposed circuit showed that the circuit followed a boost-buck input output relationship. Simulation of the circuit was first implemented in LTspice to verify the functionality of the new topology. Hardware implementation of the proposed design was built on a scaled-down prototype for a proof-of-concept of the new topology. The prototype specifications were created for a 5A, 20V output with a 20-24V, 60Hz input. This project demonstrated that the proposed new topology was successful in obtaining a near unity power factor and a total harmonic distortion of less than 2%. Additionally, the prototype followed the simulation and calculations of a boost-buck function while varying duty cycle, and the final measurements aligned well with waveforms from the simulation.
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Ingalls, Brian K. "A comparative study of the Nubian and American dentitions arch width, the missing dimension : submitted in partial fulfillment ... orthodontics ... /." 1985. http://books.google.com/books?id=jpE9AAAAMAAJ.

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50

Thiyagarajan, Ramya. "A longitudinal study of dental arch dimensions in Australian aboriginals using 2D and 3D digital imaging methods." 2008. http://hdl.handle.net/2440/50873.

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This study investigated arch dimension changes associated with growth and tooth wear in Australian Aboriginals aged from age 8 to 15 years using 2D and 3D digital imaging systems. Serial dental casts of Australian Aboriginals from Yuendumu were used in the study. The sample comprised 25 females and 24 males for whom casts were available at ages of 8, 12 and 15 years ( a total of 294 dental study casts). The primary method of data acquisition involved obtaining digital photographs and digitizing the images using an Apple IIGS computer and customised software program. A subset of 40 dental stone models (5 individuals at ages 8, 12, 15 and 18 years) were duplicated and scanned using the Minolta Vivid 900 laser surface scanner at the DSIRO Laboratories, National University Singapore. The 3-D images were digitised using the Rapidform software package (Inus, technology, Seoul, Korea). Study variables included mesiodistal crown diameters, arch widths, arch depths and arch lengths. Mesiodistal crown dimensions in males tended to be larger than those in females. All arch dimensions were significantly larger in males than females. Upper and lower Intercanine width increased from age 8 to age 12 years but did not change thereafter. Upper and lower intermolar widths increased with age from 8 years to 15 years while arch depth decreased. No significant reduction in arch lengths was found from age 12 to 15 years. The two imaging systems were comparable in their measurement reliability, although the 2D method provided consistently larger crown diameters than the 3D method. Changes in arch dimensions with age in the Aboriginal sample were similar to those reported for other populations. However, no measurable change was detected in arch length over time, even though the Aboriginals had abrasive diets that would be expected to contribute to interproximal wear. It was concluded that the 2D and 3D imaging methods were suitable for clinical use but would require further refinement for research projects aimed at assessing minor changes in arch lengths associated with interproximal wear.
http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1347947
Thesis (D.Clin.Dent.) -- University of Adelaide, School of Dentistry, 2008
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