FE-modeling is a rapidly spreading method to analyze structures nowadays. With this theunderstanding of the outcome is of very high importance and potential inaccuracies areimportant to find so that faulty and over dimensioning of the structure does not occur whichleads to unnecessary costs. One of these inaccuracies is the unrealistic sectional forces that occurdue to thermal effects in the transversal direction for concrete frame bridges which leads to anexcessive amount much reinforcement in the structure than actually needed. This has beenstudied with several cases by using two approaches on how to apply the temperature in the framebridge, only in the superstructure and in the whole structure, but also by analyzing severalboundary conditions. By examining the results for the sectional forces and stresses one of thetemperature approaches could be disregarded because of the extreme values in the transitionbetween superstructure and support. But the other approach was much more useful because ofits better compliance with reality. With these results and by calculating the reinforcement neededfor the worst case, one model has been found to be the most favorable and can be used whenmodeling concrete frame bridges with acceptable outcome. The study resulted in a model whereone applies a varying temperature on the whole structure, with spring boundary conditions over asurface that represents the bottom slab.

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In the past few years a new class of layered piezoceramic and piezoceramic-composite actuators, known as RAINBOW and GRAPHBOW, respectively, that are capable of achieving 100 times greater out-of-plane displacements than previously available has been developed. Prior to the development of RAINBOW and GRAPHBOW, large stacks of piezoelectric actuators, requiring complicated electronic drive circuits, were necessary to achieve the displacement now possible through the use of a single RAINBOW actuator. The major issues with both RAINBOW and GRAPHBOW are the prediction of their room-temperature shapes after processing, and their deformation response under application of electric field. In this research, a methodology for predicting the manufactured shapes of rectangular and disk-style RAINBOW and GRAPHBOW is developed. All of the predictive analyses developed are based on finding approximate displacement responses that minimize the total potential energy of the devices through the use of variational methods and the Rayleigh-Ritz technique. These analyses are based on classical layered plate theory and assumed the various layers exhibited linear elastic, temperature-independent behavior. Geometric nonlinearities are important and are included in the strain-displacement relations. Stability of the predicted shapes is determined by examining the second variation of the total potential energy. These models are easily modified to account for the deformations induced by actuation of the piezoceramic. The results indicate that for a given set of material properties, rectangular RAINBOW can have critical values of sidelength-to-thickness ratio (Lx/H or Ly/H) below which RAINBOW exhibits unique, or single-valued, spherical or domed shapes when cooled from the processing temperature to room temperature. For values of sidelength-to-thickness ratio greater than the critical value, RAINBOW exhibits multiple room-temperature shapes. Two of the shapes are stable and are, in general, near-cylindrical. The third shape is spherical and is unstable. Similarly, disk-style RAINBOW can have critical values of radius-to-thickness ratios (R/H) below which RAINBOW exhibits axisymmetric room-temperature shapes. For values of R/H greater than the critical value, disk-style RAINBOW exhibits two stable near-cylindrical shapes and one unstable axisymmetric shape. Moreover, it is found that for the set of material properties used in this study, the optimal reduced layer thickness would be at 55%, since the maximum change in curvature is achieved under the application of an electric field, while the relationship between the change in curvatures and the electric field is kept very close to being linear. In general, good agreement is found for comparisons between the predicted and manufactured shapes of RAINBOW. A multi-step thermoelastic analysis is developed to model the addition of the fiber-reinforced composite layer to RAINBOW to make GRAPHBOW. Results obtained for rectangular RAINBOW indicate that if the bifurcation temperature in the temperature-curvature relation is lower than the composite cure temperature, then a unique stable GRAPHBOW shape can be obtained. If the RAINBOW bifurcation temperature is above the composite cure temperature, multiple room-temperature GRAPHBOW shapes are obtained and saddle-node bifurcations can be encountered during the cooling to room temperature of [0°/RAINBOW], [RAINBOW/0o], and [0o2/RAINBOW]. Rectangular [RAINBOW/0o/90o] seems to be less likely to encounter saddle-node bifurcations. Furthermore, the unstable spherical RAINBOW configuration is converted to a stable near-cylindrical configuration. For the case considered of disk-style GRAPHBOW, three stable room-temperature shapes are obtained and the unstable axisymmetric RAINBOW configuration is also converted to a stable near-cylindrical configuration. For both rectangular and disk-style GRAPHBOW, the relationship between the major curvature and the electric field is shown to be very close to being linear. This characteristic would aid any dynamic analysis of RAINBOW or GRAPHBOW. / Ph. D.

Much of North America’s reinforced concrete infrastructure is reaching the end of its service life and careful inspection and assessment is required to ensure the appropriate capacity is maintained in these structures. The research conducted herein seeks to further the development of two new sensor technologies: fibre optic strain sensors and digital image correlation, which have the potential to provide comprehensive performance data for structures to a level of accuracy previously not possible. The research involves determining the accuracy of these sensor systems to monitor both strain and crack widths in reinforced concrete compared to conventional techniques, such as electrical resistance strain gauges. Preliminary work was also undertaken on correcting the sensor results for temperature. It was determined that temperature variations in the range of +21 °C to 20 °C, result in significant strain errors for both sensor systems. Once the results obtained from the sensors systems are corrected for temperature, crack widths are monitored in four small-scale reinforced concrete tension specimens, and strain and crack width behaviour is monitored in four full-scale beams under four point bending. One of the major problems faced when using the digital image correlation technique is out of plane movement which results in significant error. Techniques to lower this error are addressed. In addition, obtaining a more robust understanding of the effects of temperature on crack widths, stiffness, strength and short term creep behaviour of reinforced concrete elements is explored to improve structural monitoring and numerical models used for analysis. Four full-scale beams, two at room temperature and two at 20 °C, were loaded to failure under four point bending. A comparison of the room temperature and low temperature test results show that the cracks tend to close up at lower temperatures in members that are free to expand and contract. This behaviour results in a potential increase in shear capacity for beams at lower temperatures. The low temperature beams also saw a minor increase in strength, but saw no noticeable increase in stiffness. Lastly, short term creep behaviour was reduced in the low temperature beams once the formation of ice occurred. / Thesis (Master, Civil Engineering) -- Queen's University, 2012-10-31 11:08:32.631

L’objectif de la thèse est de développer une nouvelle technique d’optique adaptive pour les interferomètres gravitationels avancés, basée sur un nouveau type de miroir pour le faisceau d’injection de l’interferomètre. Le miroir déformable, basé sur une actuation thermique, doit etre un outil compatible ultra-vide, qui fonctionne sans bruit électronique ou mécanique, bon marché et permettre la correction des modes d’ordre supérieurs afin d’améliorer le matching des faisceaux de haute puissance dans les cavités laser du détecteur sous ultra-vide. Un montage experimental de caractérisation du miroir déformable a été mis en place afin d’effectuer les tests de validation du premier prototype sous air. L’élaboration d’une procédure de caractérisation des propriétés du miroir et d’une boucle de controle a permis de développer une approche efficace pour déterminer les possibilités et les limites du miroir. Nous avons ainsi pu faire la démonstration de sa capacite a corriger les aberrations de phase d’un faisceau laser infrarouge a différentes fréquences spatiales. Nous avons également démontré que le miroir vérifie les performances de stabilité, de reproductibilité et de linearité attendues. Nous avons ensuite validé l’amélioration du mode matching d’un faisceau laser sur une cavité de réference par le miroir thermiquement déformable / In this thesis we develop a new technique of adaptive optics for the Advanced Gravitational Interferometers, based on a new type of deformable mirror for the injection beam of the interferometer. This deformable mirror, based on a thermal actuation, has to be a high vacuum compatible and low-cost device, that is working without any electronic or mechanic noise. It has to allow the correction of high order modes to improve the matching of high power laser beams in the interferometer.An experimental setup has been made to characterize the first prototype on air. An efficient process and a control loop have allowed to determine the possibilities and limits of the device. We have demonstrated its ability to correct high order modes of an infrared laser beam. Afterwards, we have validated the improvement of mode matching into a fixed cavity.

Esta dissertação está focada no estudo do espectro de absorção em fase gasosa de Porfirinas e Ftalocianinas. O estudo dessas moléculas é de grande interesse científico e tem sido tema em diversos trabalhos na literatura. São apresentados resultados para o espectro de absorção teórico das Porfirinas Base Livre (H2-Porfirina), complexada com Zinco, e complexada com Magnésio, e das Ftalocianinas Base Livre (H2-Ftalocianina) e complexada com Zinco. Espectros de absorção dos monômeros optimizados dessas moléculas são calculados com vários métodos e uma análise das transições eletrônicas é feita junto com uma discussão do modelo de Gouterman. São apresentados espectros para estruturas optimizadas de dímeros de H2-Porfirina e H2-Ftalocianina. A inclusão de efeitos térmicos no espectro dos monômeros de H2-Porfirina e H2-Ftalocianina é estudada usando dinâmicas moleculares. Após comparação entre resultados de dinâmicas clássica e ab initio, propomos novos parâmetros para o campo de força da H2-Porfirina que fornece resultados mais compatíveis, mas o mesmo não precisou ser feito para H2-Ftalocianina. Mostramos que para H2-Porfirina a inclusão de efeitos térmicos aumenta com a temperatura as forças de oscilador médias das bandas Q e gera um deslocamento das bandas para o vermelho, e para H2-Ftalocianina um aumento do desdobramento das bandas Q. Esses resultados fornecem uma explicação para observações experimentais e mostram que efeitos térmicos são importantes para uma descrição mais completa do espectro. / This work aims at studing the gas phase absorption spectrum of Porphyrins and Phthalocyanines. The study of these molecules is of immense cientific interest and has been topic for several works at the literature. Results are presented for the theoretical absorption spectrum of Free Base (H2-Porphyrin), Zinc and Magnesium Porphyrins and of Free Base (H2-Phythalocyanine) and Zinc Phthalocyanines. The absorption spectra of these molecules\' optimized monomers are calculated with several methods and eletronic transitions analysis is done together with a discussion of Gouterman model. Spectra are presented for optimized dimers of H2-Porphyrin and H2-Phythalocyanine. The inclusion of thermal effects on the H2-Porphyrin\'s and H2-Phythalocyanine\'s monomer spectra is studied through molecular dynamics. After comparing results of classical and ab initio molecular dynamics we proposed new force field parameters for H2-Porphyrin that provides more consistent results, but the same didn\'t need to be done for H2-Phythalocyanine. We showed that the inclusion of thermal effects increases with temperature the Q bands average oscillator strengths and implies in a red shift of the H2-Porphyrin bands, and increases the H2-Phythalocyanine\'s Q bands splitting. These results provide an explanation to the experimental observations and shows that thermal effects are important to a more complete description of the spectrum.

O uso de biomassas para biossorção de metais pesados é bem documentado na literatura e vários tipos de espécies de microrganismos e algas já foram testados. A maior parte destes trabalhos foi realizada com biomassa seca para prevenir qualquer resposta metabólica indesejável. Vários estudos na literatura sugerem o uso de biomassa seca sobre condições moderadas, tais como secagem ao sol; por outro lado, vários trabalhos recomendam a faixa de 313K a 353K para garantir completa inativação da biomassa. O efeito da biomassa seca ao sol a 303K e seca a 333K em estufa na remoção de Cd2+ é aqui reportado. A avaliação dos resultados foi baseada na cinética e capacidade de remoção do metal pela alga Sargassum filipendula. Os resultados indicam que a adsorção máxima de metal não foi notadamente reduzida quando a biomassa seca em estufa foi usada, para concentrações de cádmio na faixa de 10,0 a 500,0 mg L-1. O estudo cinético realizado indicou que o modelo de pseudo segunda ordem ajustou melhor os dados experimentais, tanto para uma solução diluída (10 mg L-1) quanto para a concentrada (100 mg L-1). Em ambos os casos, os efeitos da secagem em estufa, a 60C refletiu-se suavemente na remoção do metal. Os dados experimentais foram melhor ajustados pelo modelo de Langmuir em comparação com o modelo de Freundlich. Análises termogravimétricas mostraram que não havia dano estrutural no biossorvente devido à secagem em estufa. O espectro de infravermelho não indicou diferença entre a biomassa in natura e seca. O efeito da temperatura na biossorção do metal significativo na faixa de 303K a 328K, refletindo-se na capacidade de remoção do cádmio / The use of biomass for biosorption of heavy metals is well documented in the literature and several types of microbial species and seaweeds were already tested. Most of these works are conducted with dry biomass in order to prevent any undesirable metabolic response. Several literature reports suggest drying the biomass under mild conditions, such as sun-drying; on the other hand, several reports recommend the range from 313 K to 353 K to ensure complete inactivation of the biomass. The effect of sun-drying the biomass at 303 K and oven-drying at 333 K in Cd2+ ions remotion is here reported. Evaluation of results was based on the kinetics and uptake capacity of the metal by the seaweed Sargassum filipendula. Results indicated that the maximum metal uptake was not markedly reduced when oven-dried biomass was used, for cadmium concentrations ranging from 10.0 to 500.0 mg L-1. Kinetic tests performed indicated a better fit of the experimental data to the pseudo second order model, both for a dilute (10 mg L-1) and a concentrated solution (100 mg L-1). In both cases the effect of drying in an oven, at 333 K was slightly reflected in the uptake. Results were best represented by the Langmuir model in comparison to the Freundlich model. Thermogravimetric analysis confirmed that no structural damage due to drying at high temperatures was observed. Infrared spectra indicated no difference between the in natura and dried biomass. The effect of temperature on the metal uptake was significant in the range from 303 to 328 K, reflected in the cadmium uptake capacity

Magistriniame darbe įvertinamas Ignalinos atominės elektrinės ir gamtinių sąlygų poveikis terminiam Drūkšių ežero režimui. Tyrimo tikslas – įvertinti Ignalinos atominės elektrinės ir gamtinių sąlygų poveikį terminiam Drūkšių ežero režimui. Tyrimo objektas – atominė elektrinė ir Drūkšių ežeras. Nuo l984 m. Lietuvos didžiausias Drūkšių ežeras pradėjo tarnauti kaip Ignalinos atominės elektrinės (IAE) aušintuvas. Todėl natūralus hidrologinis režimas ir šilumos balansas ežere buvo sutrikdyti. Ypač pakito Drūkšių ežero terminis režimas. Vidutiniškai Drūkšių ežero vandens temperatūra pakilo apie 3,5 ºC. Tačiau pastaraisiais metais Lietuvoje stebimos klimato atšilimo tendencijos. Per pastaruosius dešimtmečius vidutinė oro temperatūra padidėjo apie 1 ºC. Oro temperatūros augimas taip pat turėjo įtakos visų vandens telkinių, tuo pačiu ir Drūkšių ežero vandens temperatūrai. Todėl tiek antropogeniniai veiksniai (atominė elektrinė), tiek gamtiniai veiksniai (klimato kaita) turi įtakos Drūkšių ežero terminiam režimui. Lietuvos energetikos instituto ir kitų mokslinių institucijų darbuotojai atliko daug tyrimų, susijusių su Drūkšių ežero hidrologine, hidrotermine bei ekologine būkle. Tačiau šiuose tyrimuose mažai dėmesio buvo skirta gamtinės kaitos įtakos Drūkšių ežero terminiam režimui nustatymui. Šio tyrimo tikslas buvo įvertinti atominės elektrinės ir gamtinių sąlygų poveikį terminiam Drūkšių ežero režimui. Norint įvertinti Drūkšių ežero terminio režimo pokyčius veikiant IAE... [toliau žr. visą tekstą] / The paper evaluated the Ignalina nuclear power and natural conditions, the thermal effect of the lake Drūkšiai regime. Purpose of the survey - to assess the Ignalina nuclear power and natural conditions on the thermal regime of Lake Drūkšiai. The object of research - nuclear power and natural environment impacts. Since l984, the Lithuanian Drūkšiai largest lake began to serve as the Ignalina Nuclear Power Plant (INPP) cooler. Therefore, the natural hydrological regime and heat balance in the lake has been disturbed. In particular, changes in lake thermal regime Drūkšiai. On average, Drūkšiai lake temperature has risen approximately 3.5 ° C. However, in recent years, Lithuania observed warming trends. Over the past decades, the average air temperature increased about 1 ° C. Air temperature rise is also affected by the water at the same time and lake water temperatures. Therefore, both anthropogenic factors (NPP) and natural factors (climate change) affect the thermal regime of Lake Drūkšiai. Lithuanian Energy Institute and other scientific staff, the large number of tests and touching Drūkšiai lake hydrology, hydrothermal and ecological condition. However, these studies little attention was given to natural changes affect Drūkšiai lake thermal regime. Purpose of this study was to evaluate nuclear power and natural conditions on the thermal regime of Lake Drūkšiai. To assess Drūkšiai Lake thermal regime change operation IAE... [to full text]

Electrophysical agents (EPA) are a fundamental element of therapy practice and are vital for the treatment of a variety of conditions. Many of these agents employ some form of electromagnetic fields (EMF), in which radiofrequency (RF) is a major component. The therapeutic effects of RF are mainly linked to their effects on pain relief and potential effects on tissue repair. Although RF across various frequency ranges has been in use, reviews have shown that the frequency ranges currently used in therapy practice have narrowed to within 30 kHz-30,000 kHz (30 MHz). The most commonly used and hence the most commonly researched are shortwave therapies (SWT) that operate at 27.12 MHz, which is presently used predominantly in its pulsed form (PSWT). In addition to SWT, devices employing significantly lower RF ranges have also been used widely despite their lack of evidence. Capacitive Resistive Monopolar Radiofrequency (CRMRF) that operates at 448 kHz is one such RF. This programme of research was designed to investigate the physiological and clinical efficacy of CRMRF delivered using the 'Indiba Activ 902' device. The project also evaluated the scope and evidence for RF-based EPAs in therapy, through a comprehensive review of literature. A total of 120 relevant clinical studies on either acute (30 studies) or chronic (90 studies) conditions were reviewed. Notable evidence was identified for chronic OA knee and acute postoperative pain and wound healing. Some evidence also exists for chronic low back pain and healing of chronic wounds. Only eight studies reported devices that employed RF outside the shortwave frequency band. In a randomised crossover laboratory study on asymptomatic adults, the effects of contrasting doses of CRMRF on skin temperature (SKT), skin blood flow (SBF), nerve conduction velocity (NCV), deep blood flow and the extensibility of tissues were examined against a placebo dose and a control condition with no treatment. The study further compared CRMRF results with that of PSWT. The results showed that high (moderately thermal) and low (sub/minimally thermal) doses of CRMRF significantly enhanced and sustained SKT (p < 0.001), while only the high dose meaningfully increased SBF (p < 0.001). High dose PSWT increased SKT marginally (p < 0.001) but did not sustain it. Further, the high and low dose CRMRF significantly enhanced blood flow volume at depth (p=0.003), while PSWT failed to show any significant impact. None of the treatments significantly affected deep blood flow velocity, tissue extensibility or NCV. These results were reproduced on a cohort of patients affected by OA knee in a randomised controlled trial (RCT), and the effects appeared more pronounced in the patients than in the asymptomatic people. More importantly, the RCT showed that a four-week high dose CRMRF treatment (eight sessions) produced statistically and clinically significant gains in pain and function associated with OA knee in the short to medium term (p < 0.001), which was also significantly more pronounced than the gains produced by a placebo, or standard care (p=0.001for pain; p=0.031 for function). The findings of this study were considered promising. It is therefore suggested that CRMRF-based treatment can potentially be used as an adjunct to current therapeutic methods to enhance the clinical outcomes. However, further studies are needed to substantiate this, and the current results will provide credible baseline data for future research.