K3 ENDO, PRO TAPER, AND PRO FILE SYSTEMS: BREAKAGE AND DISTORTION IN SEVERELY CURVED ROOTS OF MOLARS.By Matthew T. Ankrum, D.D.S.A Thesis submitted in partial fulfillment of the requirements for the degree of Master of Science at Virginia Commonwealth University.Virginia Commonwealth University, 2003Major Director: Gary R. Hartwell, D.D.S., M.S.Chairman and Professor, Department of EndodonticsIt was the aim of this study to investigate the incidence of file breakage and distortion when the Pro Taper, K3 Endo and ProFile systems were used to instrument canals in the severely curved roots of extracted molars.Forty-five roots of extracted mandibular and maxillary molars with curvatures between 40 and 75 degrees were chosen for use in this study. The roots in Group One were instrumented with the Pro File (PF) system and served as the control group. Roots in Group Two were instrumented with the Pro Taper (PT) system and those in Group Three were instrumented with the K3 Endo (K3) system. The three systems were used according to the manufacturers' instructions.The proportion of files distorted was 15.3% for the PF group, 2.4% for the PT group, and 8.3% for the K3 group. There was a statistically significant difference between the PF and PT groups (p = .0079). The percentage of broken files was 1.7% for the PF group, 6.0% for the PT group and 2.1% for the K3 group. No statistically significant differences were found between these three groups (p = .4243). The results of this study showed that these three rotary tapered systems were not significantly different with regard to breakage. There were significantly more distorted files in the PF group when compared to the PT group, with regard to distortion there was no significant difference between the PT and K3 and the PF and K3 groups.

Augmented reality (AR) systems are often used to superimpose virtual objects or information on a scene to improve situational awareness. Delays in the display system or inaccurate registration of objects destroy the sense of immersion a user experiences when using AR systems. AC electromagnetic trackers are ideally for these applications when combined with head orientation prediction to compensate for display system delays. Unfortunately, these trackers do not perform well in environments that contain conductive or ferrous materials due to magnetic field distortion without expensive calibration techniques. In our work we focus on both the prediction and distortion compensation aspects of this application, developing a “small footprint” predictive filter for display lag compensation and a simplified calibration system for AC magnetic trackers. In the first phase of our study we presented a novel method of tracking angular head velocity from quaternion orientation using an Extended Kalman Filter in both single model (DQEKF) and multiple model (MMDQ) implementations. In the second phase of our work we have developed a new method of mapping the magnetic field generated by the tracker without high precision measurement equipment. This method uses simple fixtures with multiple sensors in a rigid geometry to collect magnetic field data in the tracking volume. We have developed a new algorithm to process the collected data and generate a map of the magnetic field distortion that can be used to compensation distorted measurement data.

We study the continuity of mappings of finite distortion, a set of mappings intended to model elastic deformations in non-linear elasticity. We focus on continuity criteria for the inner-distortion function and prove that certain modulus of continuity estimates are sharp, i.e. cannot be im- proved. We also give a proof of the continuity of mappings of finite distortion under simplified conditions on the integrability of the distortion function. 1

The purpose of this dissertation was to determine the usefulness of the linguistic processes of Distortion, Deletion, Generalization, and Semantic Ill-Formedness as constructs which differentiate the verbal communication of families who express dissatisfaction with their current intrafamilial relationships from families expressing satisfaction with their current relationships. Specifically, it was hypothesized that dissatisfied families would use these linguistic structures to a greater extent in their interaction than would satisfied families. Thirty-one family triads (father, mother, and child) were obtained by asking families randomly selected from the local high school student directory to participate. The families were given a Revealed Differences questionnaire which they subsequently discussed together and a questionnaire regarding their satisfaction with their intrafamilial relationships. The discussions were recorded and transcribed. Each of 150 Surface Structures (a complete thought, usually a grammatical sentence) per family was scored for 11 subcategories of Distortion, Deletion, Generalization, and Semantic Ill-Formedness. Interrater reliabilities ranged from .86 to .98. A mean was computed for the questionnaire pertaining to satisfaction with family relationships. Six families who scored at least one half standard deviation below the mean comprised the "dissatisfied" family group, and six families who scored at least one half standard deviation above the mean comprised the "satisfied" family group. It was found that the dissatisfied families used significantly more Deletion (p The linguistic process of Deletion is theorized to result in impoverishing the speaker's model of the world and the behavioral choices available to the speaker. Similarily, the listener(s) who must respond to the impoverished model is limited in his response and behavioral options. Since all members of the dissatisfied families used this form of language, they perpetuate the impoverishing model of the world and the limitations on their behavior. It was concluded that, while not establishing an etiologic link between the use of Deletion and family dissatisfaction, Deletion is part of the current verbal interaction of families who express dissatisfaction. Further research involving families in which a member is symptomatic is warranted based on the findings of this study. Language may provide at least one form of explanation regarding the process by which families maintain homeostasis in the face of symptom development. The use of linguistic concepts shows promise as an intermediate link in family interaction theory as well as a form of intervention available to therapists.

M.Ing. / Please refer to full text to view abstract

[pt] Os principais problemas causados pela passagem de múltiplas portadoras por dispositivos não lineares são, conhecidamente, a conversão AM/AM, a conversão AM/PM, e a intermodulação. Estes problemas estão presentes tanto na transmissão via satélite, onde amplificadores de alta potência (HPAs) e transponders não lineares estão presentes, quando na radiodifusão terrestre onde, com o objetivo de ampliar ao máximo o tamanho da área geográfica na qual o serviço é oferecido, são utilizados amplificadores de alta potência operando em sua região não-linear. Neste contexto encontram-se os sinais multiportadora do tipo OFDM, amplamente utilizados na radiodifusão de sinais digitais de TV. Com o objetivo de minorar efeitos de canais não lineares sobre sinais OFDM, o presente trabalho propõe a utilização de um esquema de pré-distorção não linear modelado matematicamente através de uma série complexa de potências. Duas estratégias são consideradas no dimensionamento do esquema de pré-distorção: a redução da soma das potência dos produtos de intermodulação de ordens especificadas e a equalização das potências dos diversos produtos de intermodulação. Analises de configurações baseadas nestas duas estratégias são apresentadas juntamente com resultados numéricos envolvendo situações específicas de interesse. / [en] The main problems of multiple carriers through non-linear devices are, AM / PM conversion, conversion AM / PM conversion, and intermodulation. These problems are usually present in satellite transmissions, where high-power amplifiers (HPAs) and nonlinear transponders are used, as well as in terrestrial broadcasting systems where, in order to enlarge the service area(geographical area in which the service is offered). High-power amplifiers operating in their non-linear region are used. The multicarrier transmission called OFDM, which is widely used in TV broadcasting digital signals falls in this context. In order to alleviate the effects of nonlinear channels on OFDM signals, the present study suggests the use of a pre-distortion system mathematically described through a complex power series. Two Strategies are considered in order to determine the pre-distortion system parameters: the reduction of the intermodulation power sum associated to intermodulation products of any specified order, and the equalization of the intermodulation power associated to intermodulation product of various orders. Analysis of configurations based on these two strategies are presented together with numerical results involving situations of specific interest.

The primary aim of the research was to describe hearing function in a group of children with chronic renal dysfunction receiving treatment in an academic hospital in Johannesburg, South Africa. Specific objectives in the study were to determine the prevalence of hearing loss in paediatric patients with chronic renal dysfunction; to describe the type, degree and configuration of the hearing loss; and to establish if there was a relationship between the presenting hearing loss and the severity of renal dysfunction, the different treatment regimens, duration of renal dysfunction, and the duration of treatment. One hundred children between the ages five -18 years participated in the study and comprised 65 males and 35 females. The mean age of the participants was 11.68 years. A cross-sectional, descriptive, quantitative research design was employed. All participants underwent a case history interview and a full audiological examination which included an otoscopic examination, immittance testing (tympanometry and ipsilateral acoustic reflex testing), pure tone audiometry including extended high frequency testing up to 16 kilohertz as well as diagnostic distortion product otoacoustic emission testing. A record review was also done. Both descriptive and inferential statistics were used to analyse the collected data. Inferential statistics included parametric measures using multiple regression measures as well as non parametric measures using the Kruskal-Wallis statistical analysis. Results revealed that there was a high prevalence of hearing loss in children with chronic renal dysfunction. Results from the extended high frequency pure tone testing as well as the diagnostic distortion product testing revealed that the most common hearing loss was a low and high to ultrahigh frequency mild sensorineural hearing loss. The study showed that there was no relationship between the severity of hearing loss and the severity of renal dysfunction, or the duration of renal dysfunction and the duration of treatment. However, the study showed that there was a relationship between the severity of hearing loss and certain treatments, that is, v haemodialysis and the use of ototoxic medication such as loop diuretics, tuberculosis medication, and antimalarial medication. As the potential to miss hearing loss in this population is high, the research highlighted the importance of extended high frequency audiometry as well as diagnostic distortion product otoacoustic emission testing for the use of ototoxic monitoring in patients with chronic renal dysfunction. The research also highlighted the need for further research in this area as well as the need for educating medical personnel and caregivers working with children with chronic renal disease.

Purpose: The main objective of the current study was to investigate and monitor the auditory status in a group of adult patients with AIDS receiving antiretroviral therapy (ART) and other therapies in a hospital outpatient clinic in Gauteng, South Africa. Specific objectives included estimating the prevalence of hearing loss and the presence of other otologic effects over and above hearing impairment (tinnitus, aural fullness, disequilibrium, and so forth); assessing the type, degree and configuration of the hearing loss; exploring the type of hearing symptom onset; documenting case history data such as signs and symptoms of each participant and identifying any associations between obtained signs and symptoms and hearing loss; documenting the names of all medications used and their possible impact on hearing function (specifically ototoxicity monitoring of ART); and comparing the results of the experimental group to those of a control group.

Thesis advisor: Stephen D. Wilson / This dissertation investigates the cubic type II superconductor, Ca₃Ir₄Sn₁₃, discovered by Remeika and the coauthors more than 30 years ago. It was originally discovered be to a superconductor and later suggested to host ferromagnetic spin fluctuations, which lead to a peak-like anomaly in thermodynamic and transport measurements. Later detailed x-ray single crystal structural refinement associated the peak-like anomaly in transport and magnetization measurements with a charge density wave phase transition at the same temperature. The potential charge density wave phase transition T* can be suppressed either by pressure or chemical potential through substitution on the Ca and Ir site such that a temperature-pressure/composition phase diagram can be constructed. Upon investigating magnetism in this compound, polarized neutron scattering and μSR data from our group and other researchers did not reveal any magnetic order or magnetic spin fluctuations at the time scale of μSR . However, through the partial substitution of Ir by Rh, we realized a structural quantum critical point at ambient pressure with 30% of Ir substituted by Rh--providing the research community a valuable material's platform for studying the interplay between 3D charge density wave order and superconductivity. On the other hand, our surprising discovery of the weak HHL (L=odd) type of super-lattice peaks from neutron scattering led us to a tentative model of a distorted Ca sublattice in this material. The similarity of the lattice instabilites of the Remeika compound and A15 superconductors are discussed, which may give us more insight into its role in the formation of the superconducting phase. / Thesis (PhD) — Boston College, 2015. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Physics.

A Agência Nacional de Energia Elétrica (ANEEL) deverá estabelecer a regulamentação para distúrbios de qualidade de energia em um futuro próximo. Há ainda questões em aberto sobre os procedimentos de medição e limites máximos para os indicadores de qualidade de energia. Este trabalho aborda uma dessas questões, que é a conexão de transdutores e os impactos nos índices de qualidade de energia associados. Simulações em ATPDraw e campanhas de medição foram realizadas de modo a identificar o comportamento dos indicadores de distorção harmónica sob as duas configurações possíveis de conexão de transdutores: dois equipamentos com ligação entre fases ou três com ligação fase-neutro. Os resultados das simulações e os valores medidos mostram grandes discrepâncias entre ambas as configurações, e as diferenças tornam-se ainda mais significativas com o incremento do desequilíbrio do sistema elétrico. As causas subjacentes deste fenômeno são investigadas e discutidas / The Brazilian electricity regulatory agency (ANEEL) is expected to establish a legal framework for quality disturbances in the near future. There are still some open questions regarding metering procedures and maximum limits for Power Quality indicators. This work addresses one of such issues, namely the connection of the associated transducers and its impact on PQ indexes. Simulations in ATPDraw and on-field measurement campaigns were carried out so as to identify the behavior of harmonic distortion indicators under the two possible transducer configurations: two phase-to-phase or three phase-to-neutral transducers. Simulation results and measured values show large discrepancies between both configurations, and the differences become more significant as the electrical systems unbalance increases. The underlying causes of this phenomenon are investigated and discussed.