With many unique advantages compared to traditional sensors, optical fiber sensors have been studied and applied to many different areas. Interferometric sensors are one of the most useful sensor types due to their high sensitivities and relatively relaxed requirement on the stability of the optical source’s power level. In-line optical interferometric sensors received further attention as a result of compactness and robustness to the reference channel instability. Long period gratings (LPG) are one of the most useful components in the in-line optical fiber sensors. However, the fabrication cost is normally high due to the expensive masks and stringent photolithographic procedures. Two new sensor components, namely abrupt tapers and connector-offset attenuators, are proposed as couplers in the optical fiber to couple light from core to cladding (or reverse) to replace LPGs. Using OPTIBPM software, the coupling coefficients between core and cladding modes are calculated. For an abrupt taper, coupling mostly happens between LP01 and LP0m modes; the first ten LP0m modes account for 98% of the incident mode energy. For a connector-offset attenuator, coupling mainly happens between LP01 and LP1m modes; the first ten LP0m and first ten LP1m modes account for 92% of the incident mode energy. The relative direction of two connector-offset attenuators is found to be very important to the interference performance. Phase dependent interference (attenuation range from 1 dB to 35 dB) is observed in the simulation for the interferometers using abrupt tapers and connector-offset attenuators. Three interferometers are realized in the experiment using the abrupt tapers (Mach-Zehnder and Michelson) or the connector-offset attenuators (Michelson). Due to the interference between core and cladding modes, transmission is strongly dependent on wavelength ranging from 3 dB to 26 dB in the best implementation. Although it is difficult to make two perfect parallel connector-offset attenuators required by the Mach-Zehnder interferometers by using the fusion splicer, some evidence of constructive interference is observed in the experiment. The interferometers are tested as refractive index (RI) sensors using the maximum attenuation wavelength shift relative to the RI change. Given that the minimum resolution of optical spectrum analyzer is 10 pm, ~10-4 difference of the RI can be detected by the interferometric sensors using the abrupt tapers or the connector-offset attenuators. / Thesis (Master, Physics, Engineering Physics and Astronomy) -- Queen's University, 2008-08-18 15:42:59.506

A prototype imaging array utilizing tapered slot antenna elements is investigated for potential use in radio astronomy. The design utilizes a previously reported substrate integrated waveguide style feed for the antenna element. The reported behavior of a tapered slot antenna is reproduced within CST Microwave Studio simulator, and the design parameters in the previous design were ported to a higher frequency and adjusted to increase directivity. Approximately symmetric 3 dB beamwidths are achieved in the simulator. Array simulation is limited in scope; a prototype, sixteen element planar array was fabricated and measured. Mutual coupling effects between elements cause adverse radiation performance compared to simulated predictions. Array performance is improved by using an alternate array configuration that introduced electrical boundaries between adjacent elements. Cross-polarization performance and array element spacing remain significant challenges to the antenna and feed technology for use in radio astronomy.

The purpose of this experiment was to examine the efficacy of implementing a high intensity, high volume workout into the late stages of a taper, to identify if there was a performance enhancing effect beyond that of an intensity maintained, reduced-volume taper. Eleven male collegiate rowers (age 21.0 ± 1.9 years, VO2max 60.9 ± 5.8 ml/kg/min) completed 23 days of progressively overloaded training, followed by 5 days of reduced training volume. Participants were matched and randomly assigned to either a high intensity-low volume or high intensity-high volume treatment workout approximately 48 hours prior to an indoor rowing competition. Other than the treatment workout, all prescribed training was identical. Both tapers resulted in significant improvements in 2000 m ergometer performance; however there was no statistically significant difference between these groups (Low volume: 5.4 ± 2.7 seconds High volume 4.0 ± 3.3 seconds) Post race blood lactate tended to be higher following taper, however it did not reach significance (p = 0.06) and there was no difference between groups. There were no differences throughout training and taper for hemoglobin (Hb), hematocrit (Hct.), and plasma volume in either group. Mean corpuscular volume (MCV), increased with training and increased further with taper in both groups; conversely, red cell distribution width (RDW) decreased with training and decreased further with taper in both groups. Jump height did not change from pre-taper to competition; however, there was a decrease in dip depth and a corresponding increase in peak acceleration and rate of force development in both groups. There was also a reduction in fatigue at competition compared to week 2 as measured by the Profile of Mood States questionnaire. These physiological and psychological adaptations may in part explain the observed combined 1.8% improvement in 2000m ergometer performance compared to pre-taper test times, however we were unable to discern any differences in any measured parameters between the higher volume and low volume treatment groups. The changes in hematological parameters may be indicative of decreases in erythrocyte age; and the adaptations to acceleration / rate of force development suggest potential improvements under the broad theme of movement economy. This study found that employing a 5 day reduced volume taper improved performance, however, implementing a higher volume, high intensity stimulus 48-52 hours prior to competition resulted in no added benefit and a potentially meaningful (1.4 seconds) yet not significant reduction in performance response to taper.

We analyze by simulation the properties of two time domain and two frequency domain estimators for low order autoregressive fractionally integrated moving average Gaussian models, ARFIMA (p,d,q). The estimators considered are the exact maximum likelihood for demeaned data, EML, the associated modified profile likelihood, MPL, and the Whittle estimator with, WLT, and without tapered data, WL. Length of the series is 100. The estimators are compared in terms of pile-up effect, mean square error, bias, and empirical confidence level. The tapered version of the Whittle likelihood turns out to be a reliable estimator for ARMA and ARFIMA models. Its small losses in performance in case of ``well-behaved" models are compensated sufficiently in more ``difficult" models. The modified profile likelihood is an alternative to the WLT but is computationally more demanding. It is either equivalent to the EML or more favorable than the EML. For fractionally integrated models, particularly, it dominates clearly the EML. The WL has serious deficiencies for large ranges of parameters, and so cannot be recommended in general. The EML, on the other hand, should only be used with care for fractionally integrated models due to its potential large negative bias of the fractional integration parameter. In general, one should proceed with caution for ARMA(1,1) models with almost canceling roots, and, in particular, in case of the EML and the MPL for inference in the vicinity of a moving average root of +1. (author's abstract) / Series: Preprint Series / Department of Applied Statistics and Data Processing

The purpose of this experiment was to examine the efficacy of implementing a high intensity, high volume workout into the late stages of a taper, to identify if there was a performance enhancing effect beyond that of an intensity maintained, reduced-volume taper. Eleven male collegiate rowers (age 21.0 ± 1.9 years, VO2max 60.9 ± 5.8 ml/kg/min) completed 23 days of progressively overloaded training, followed by 5 days of reduced training volume. Participants were matched and randomly assigned to either a high intensity-low volume or high intensity-high volume treatment workout approximately 48 hours prior to an indoor rowing competition. Other than the treatment workout, all prescribed training was identical. Both tapers resulted in significant improvements in 2000 m ergometer performance; however there was no statistically significant difference between these groups (Low volume: 5.4 ± 2.7 seconds High volume 4.0 ± 3.3 seconds) Post race blood lactate tended to be higher following taper, however it did not reach significance (p = 0.06) and there was no difference between groups. There were no differences throughout training and taper for hemoglobin (Hb), hematocrit (Hct.), and plasma volume in either group. Mean corpuscular volume (MCV), increased with training and increased further with taper in both groups; conversely, red cell distribution width (RDW) decreased with training and decreased further with taper in both groups. Jump height did not change from pre-taper to competition; however, there was a decrease in dip depth and a corresponding increase in peak acceleration and rate of force development in both groups. There was also a reduction in fatigue at competition compared to week 2 as measured by the Profile of Mood States questionnaire. These physiological and psychological adaptations may in part explain the observed combined 1.8% improvement in 2000m ergometer performance compared to pre-taper test times, however we were unable to discern any differences in any measured parameters between the higher volume and low volume treatment groups. The changes in hematological parameters may be indicative of decreases in erythrocyte age; and the adaptations to acceleration / rate of force development suggest potential improvements under the broad theme of movement economy. This study found that employing a 5 day reduced volume taper improved performance, however, implementing a higher volume, high intensity stimulus 48-52 hours prior to competition resulted in no added benefit and a potentially meaningful (1.4 seconds) yet not significant reduction in performance response to taper.

A prototype imaging array utilizing tapered slot antenna elements is investigated for potential use in radio astronomy. The design utilizes a previously reported substrate integrated waveguide style feed for the antenna element. The reported behavior of a tapered slot antenna is reproduced within CST Microwave Studio simulator, and the design parameters in the previous design were ported to a higher frequency and adjusted to increase directivity. Approximately symmetric 3 dB beamwidths are achieved in the simulator. Array simulation is limited in scope; a prototype, sixteen element planar array was fabricated and measured. Mutual coupling effects between elements cause adverse radiation performance compared to simulated predictions. Array performance is improved by using an alternate array configuration that introduced electrical boundaries between adjacent elements. Cross-polarization performance and array element spacing remain significant challenges to the antenna and feed technology for use in radio astronomy.

Os aços inoxidáveis dúplex compõem uma família de materiais conhecidos por apresentar uma excelente combinação propriedades mecânicas e de corrosão, e por isso têm sido amplamente estudados nos últimos anos. Contudo, essa combinação de propriedades está intrinsecamente relacionada com a microestrutura desses aços, composta por iguais quantidades de ferrita e austenita, e esse equilíbrio entre as fases é extremamente dependente dos ciclos térmicos aos quais são submetidos, sob risco, inclusive, da precipitação de fases secundárias deletérias. Sendo assim, a soldagem desses materiais exige uma série de cuidados para que ela não implique em prejuízo para suas propriedades. Nesse contexto, a soldagem por fricção surge como alternativa para a união e reparo dessas ligas, justamente por apresentar um menor aporte térmico que técnicas convencionais de soldagem. Isto posto, foi realizado um reparo pelo processo de soldagem por fricção com pino consumível em uma chapa de 12mm de espessura feita em um aço inoxidável dúplex UNS S31803. Para tanto, foram registrados os dados térmicos do processamento, analisou-se a microestrutura apresentada pela junta soldada, além de avaliar-se sua tenacidade ao impacto. Os resultados comprovaram que, embora não ocorra significativa precipitação de fases secundárias, o processo de soldagem por fricção provoca diminuição da tenacidade ao impacto do material por causar o deslocamento do equilíbrio entre as fases no sentido de formação da fase ferrítica. / Duplex stainless steels compose a family of materials known to exhibit an excellent combination of mechanical and corrosion properties, and therefore have been widely studied in recent years. However, this combination of properties intrinsically relates to the microstructure of these steels that consists of equal amounts of ferrite and austenite, and this balance between phases is extremely dependent on the thermal cycles, at risk including the precipitation of deleterious secondary phases. Thus, welding of these materials requires a lot of care so that it does not result in damage to their property. In this context, the friction welding is an alternative to the union and repair of these alloys, just by having a lower heat input than conventional welding techniques. That said, a repair by the friction taper plug welding process was made on a 12 mm plate thick in a duplex stainless steel UNS S31803. Thermal processing data were recorded, microstructure presented by the welded joint was analyzed, and evaluate is its impact toughness. The results proved that although not occur significant precipitation of secondary phases, the friction welding process causes decrease in the impact toughness of the material for causing the displacement of the equilibrium between the phases towards the formation of the ferritic phase.

Made available in DSpace on 2016-12-23T13:51:44Z (GMT). No. of bitstreams: 1 Romulo Mora.pdf: 2626430 bytes, checksum: ee373f5861d8c09f0884b13c435b815a (MD5) Previous issue date: 2011-02-03 / Este trabalho teve como objetivo verificar a exatidão e precisão das estimativas das variáveis diâmetro, altura e volume, considerando as estimativas dos parâmetros obtidos no ajuste do conjunto de dados pelo modelo original e pelas expressões de diâmetro e altura para diferentes modelos de afilamento e comprimento das seções. Para a realização do trabalho, foram cubados 70 fustes do híbrido Eucalyptus urophylla x Eucalyptus grandis em espaçamento de 3 x 2 m num talhão de 3,48 hectares com 8 anos de idade em seções de 0,5 m até atingir um diâmetro mínimo de 4 centímetros para o estudo das funções de afilamento. Para verificar a influência do comprimento das seções, todos os fustes foram medidos em dez comprimentos de seções diferentes correspondentes a 0,5 m, 1,0 m, 1,5 m, 2,0 m, 2,5 m, 3,0 m, 3,5 m, 4,0 m, 4,5 m e 5 m, começando da seção de 0,0 m até o diâmetro mínimo de 4 centímetros e separados em dois grupos, um considerando a influência da base e outro não. Os modelos utilizados na comparação das estimativas foram Baldwin, Demaerschalk, Kozak e Ormerod. No estudo da influência do comprimento das seções, utilizou-se o modelo de Demaerschalk nos diferentes comprimentos de seções analisadas. A precisão e acurácia das estimativas foram verificadas através da análise gráfica dos resíduos, do coeficiente de determinação ( ), do erro padrão da estimativa (Syx(%)), do viés (V), da média das diferenças (MD) e do desvio padrão das diferenças (DPD). Baseado nessas estatísticas foi feita uma classificação para determinar o modelo que propiciasse melhores estimativas das variáveis pelas diferentes formas de ajuste e comprimento das seções, estimando assim resultados mais exatos para as variáveis analisadas. As estimativas das variáveis diâmetro, altura e volume foram obtidas de maneira mais precisa para o modelo de Demaerschalk, considerando as estimativas dos parâmetros obtidos das expressões das variáveis diâmetro e altura em relação às estimativas baseadas nas estimativas dos parâmetros do modelo original. No estudo da influência do comprimento das seções, pode-se constatar que à medida em que se diminui o número de seções medidas no fuste, verifica-se a presença de tendência das estimativas das variáveis analisadas para os dois grupos. Comparando os resultados do grupo, com e sem influência da base, nota-se que as estimativas com influência são melhores, fato observado principalmente para a variável volume / This work had as objective to verify the accuracy and precision of estimates of diameter, height and volume variables, considering the estimates of the parameter obtained in the adjustment of data set by the original model and the expressions in diameter and height for different taper models and sections length. To conduct the study, 70 stems of Eucalyptus urophylla x Eucalyptus grandis hybrid were cubed in a spacing of 3 x 2 m, in a stand of 3,48 hectares with 8 years-old, in sections of 0,5 m until they reach a minimum diameter of 4 cm for the study of taper functions. To check the influence of the sections length, all stems were measured in ten different sections lengths corresponding to 0,5 m, 1,0 m, 1,5 m, 2,0 m, 2,5 m, 3,0 m, 3,5 m, 4,0 m, 4,5 m and 5 m, starting from the section of 0,0 m to a minimum diameter of 4 cm and separated into two groups, one considering the influence of the base and the other not. The models used in the comparison of the estimates are the ones proposed by Baldwin, Demaerschalk, Kozak and Ormerod. In the study of the sections length influence, it was used the model proposed by Demaerschalk in the different analyzed sections lengths. The precision and accuracy of the estimates were verified by graphic analysis of the waste, the determination coefficient ( ), estimated standard error (Syx(%)), bias (V), average of the differences (MD) and standard deviation of the differences (DPD). Based on these statistics, a classification was made to determine the model that would provide better variables estimates by different types of adjustment and sections length, estimating more accurate results for the analyzed variables. Diameter, height and volume variables estimates were obtained more accurately for the Demaerschalk model, considering the parameters estimates obtained from the expressions of the diameter and height variables in relation to estimates based on parameters estimates of the original model. In the study of the influence of the sections length, it can be seen that as the number of sections measures in the stem decreases, it becomes possible to verify the presence of tendency of the variables estimates for both groups. Comparing the results of the group, with and without influence of the basis, it is noted that the estimates with influence are better, which was observed mainly to the volume variable

Os aços inoxidáveis dúplex compõem uma família de materiais conhecidos por apresentar uma excelente combinação propriedades mecânicas e de corrosão, e por isso têm sido amplamente estudados nos últimos anos. Contudo, essa combinação de propriedades está intrinsecamente relacionada com a microestrutura desses aços, composta por iguais quantidades de ferrita e austenita, e esse equilíbrio entre as fases é extremamente dependente dos ciclos térmicos aos quais são submetidos, sob risco, inclusive, da precipitação de fases secundárias deletérias. Sendo assim, a soldagem desses materiais exige uma série de cuidados para que ela não implique em prejuízo para suas propriedades. Nesse contexto, a soldagem por fricção surge como alternativa para a união e reparo dessas ligas, justamente por apresentar um menor aporte térmico que técnicas convencionais de soldagem. Isto posto, foi realizado um reparo pelo processo de soldagem por fricção com pino consumível em uma chapa de 12mm de espessura feita em um aço inoxidável dúplex UNS S31803. Para tanto, foram registrados os dados térmicos do processamento, analisou-se a microestrutura apresentada pela junta soldada, além de avaliar-se sua tenacidade ao impacto. Os resultados comprovaram que, embora não ocorra significativa precipitação de fases secundárias, o processo de soldagem por fricção provoca diminuição da tenacidade ao impacto do material por causar o deslocamento do equilíbrio entre as fases no sentido de formação da fase ferrítica. / Duplex stainless steels compose a family of materials known to exhibit an excellent combination of mechanical and corrosion properties, and therefore have been widely studied in recent years. However, this combination of properties intrinsically relates to the microstructure of these steels that consists of equal amounts of ferrite and austenite, and this balance between phases is extremely dependent on the thermal cycles, at risk including the precipitation of deleterious secondary phases. Thus, welding of these materials requires a lot of care so that it does not result in damage to their property. In this context, the friction welding is an alternative to the union and repair of these alloys, just by having a lower heat input than conventional welding techniques. That said, a repair by the friction taper plug welding process was made on a 12 mm plate thick in a duplex stainless steel UNS S31803. Thermal processing data were recorded, microstructure presented by the welded joint was analyzed, and evaluate is its impact toughness. The results proved that although not occur significant precipitation of secondary phases, the friction welding process causes decrease in the impact toughness of the material for causing the displacement of the equilibrium between the phases towards the formation of the ferritic phase.

Problemas com desenho de conexões protéticas sobre implantes, microfendas, afrouxamento e, consequentemente, perdas das estruturas protéticas reabilitadoras são tópicos frequentes do estudo odontológico. Conexões do tipo Cone Morse, devido às suas características, diminuíram o índice desses problemas, abrindo uma nova perspectiva para o sucesso da prótese sobre implante. Contudo, ainda é frequente encontrar componentes que falham no desempenho, levando à falência da restauração, especialmente quando esses componentes não são bem ajustados, bem fixados ou, ainda, não possuem, na sua geometria, características suficientes para suportar as forças laterais e oclusais de um ciclo mastigatório. O objetivo deste estudo é avaliar a influência do jateamento com óxido de alumínio sobre a superfície externa dos componentes protéticos, separadamente e em conjunto, com um adesivo industrial, em uma tentativa de aumentar os valores de torque de abertura de componentes apertados em seu torque recomendado, pelo fabricante ou menor. Neste ensaio, foram utilizados 36 implantes da marca Straumann®, de 10mm de comprimento com diâmetro de 4,8 mm, os quais foram divididos em 6 grupos: Grupo 1 = controle, torque de 35 N.cm; Grupo 2 = superfície jateada com óxido de alumínio (# 320) e torque de 35 N.cm; Grupo 3 = superfície jateada com óxido de alumínio (# 320) e torque de 25 N.cm; Grupo 4 = superfície jateada com óxido de alumínio (# 100) e torque de 25 N.cm; Grupo 5 = superfície jateada com óxido de alumínio (# 320), aplicação de adesivo e torque de 25 N.cm; Grupo 6 = superfície jateada com óxido de alumínio (# 100), aplicação de adesivo e torque de 25 N.cm, que receberam componentes protéticos sólidos de 5,5 mm de altura, regulares e alterados. As modificações incluídas foram o jateamento com partículas de óxido de alumínio (100 e 320 micra) e o uso de Loctite® 277 como adesivo industrial. Os conjuntos implante-componente foram levados até uma máquina de controle de tração, Instron®, e, após a sua calibração, as amostras dos grupos foram apertadas em 35 e 25 N.cm, com um conjunto catraca-torquímetro, com checagem visual e registro no software acoplado à máquina de ensaio. Após trinta dias, os grupos foram levados à máquina novamente e o conjunto abutment-implante foi desapertado, agora somente com registro no software da máquina de ensaio. Os valores e porcentagens da diferença entre torque de aperto e desaperto foram avaliados estatisticamente, e comparados entre os grupos. Para todas as associações, o valor de p deveria ser menor ou igual 0,05, para relevância. O grupo Jateado 35 N.cm, 320 micra, não apresentou valores mais altos do que o grupo Controle no momento do torque de desaperto, assim como os grupos Jateados 25 N.cm 100 e 320 micra. Os grupos Jateados 25 N.cm, 100 e 320 micra, com adesivo, mostraram uma resistência por volta de uma vez e meia maior, no torque de desaperto do que o grupo Controle 35 N.cm. / Problems with design of prosthetic implant connections, microleakage,! loosening which leads to loss of rehabilitative prosthetic structures are frequent topics of dental study. Morse taper connections, due to its characteristics, decreased the rate of these problems opening a new perspective to the success of the prosthesis supported over implant. However, it is still frequent to find components that fail in performance leading to failure of restoration especially when these components are not well adjusted, tightened or do not have in its geometry enough characteristics to support the occlusal and lateral forces in a masticatory cycle. The aim of this study is to evaluate the influence of blasting with aluminum oxide on the outer surface of the prosthetic components separately and in conjunction with an industrial adhesive in an attempt to increase the opening torque values of components tightened on their recommended torque by the manufacturer or less, therefore allowing the dentist an early intervention in the prosthetic rehabilitation. In this test, 36 Straumann® implants of 10mm high and 4,8mm wide were used. They were divided into six groups: Group 1 Solid abutments control group - 35 N.cm tightened; Group 2 - Solid sandblasted abutments, 35 N.cm aluminum oxide 320 microns size particles; Group 3 - Solid sandblasted abutments, 25 N.cm aluminum oxide 320 microns size particles; Group 4 - Solid sandblasted abutments, 25 N.cm aluminum oxide 100 microns size particles; Group 5 - Solid sandblasted abutments, 25 N.cm aluminum oxide 320 microns size particles with glue application; Group 6 - Solid sandblasted abutments, 25 N.cm aluminum oxide 100 microns size particles with glue application, which received 5,5 mm high regular and modified solid abutments. The included modifications were sandblasting with aluminum oxide particles (100 and 320 microns) and the use of Loctite® 277 as an industrial adhesive. The samples were taken to a traction control test machine, Instron ®, and after calibration the group samples were tightened on 35 and 25 N.cm with a ratchet-wrench set with visual check. The data was recorded in a software coupled to the test machine. After thirty days the groups were brought again to the test machine and the samples were untightened. At this point the resulting data was recorded only in the testing machine software. The values and percentages of the changes between the tightening and loosening torques were recorded and compared among the study groups. For all associations a p-value < 0.05 was considered significant. The group blasted 35 N.cm, 320 microns did not show higher values than the control group at the time of loosening torque as well as groups blasted 25 N.cm 100 and 320 microns. The groups blasted 25 N.cm, 100 and 320 microns with adhesive showed a resistance around one and a half times greater in the loosening torque than the control group 35 N.cm.