Orientador: Raquel Gonçalves / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-08-06T00:21:33Z (GMT). No. of bitstreams: 1 Silva_SergioAugustoMelloda_D.pdf: 3060293 bytes, checksum: 3514c54e017be522e62c07231642a540 (MD5) Previous issue date: 2003 / Resumo: As tecnologias para produção das chapas denominadas ¿Medium Density Fiberboard¿ (MDF), confeccionadas com fibras de madeiras de reflorestamento de baixo custo e resinas fenólicas provenientes de uréia, representam para vários setores industriais uma possibilidade de agregar valores às espécies com pouco interesse comercial, possibilitando para os seguimentos industriais investimento promissores. Um aspecto importante a ser considerado sobre a utilização de resinas fenólicas na confecção de chapas MDF é que produzem emissões tóxicas poluidoras da natureza e nocivas ao ser humano. Dentro deste contexto, de acordo com o ¿Protocolo de Quioto¿ de 1997, os países industrializados precisam diminuir suas emissões combinadas de gases de efeito estufa em pelo menos 5 % até 2012. Considerando-se as exigências do ¿Protocolo de Quioto¿, este trabalho objetivou avaliar o desempenho de chapas MDF confeccionadas com poliuretana (PU) derivada do óleo de mamona, pois este produto apresenta baixos teores de toxidez sendo classificado como não poluente e não tóxico ao ser humano. A caracterização das chapas foi realizada considerando-se a utilização do equipamento de ultra-som da Marca Steinkamp modelo BP7 com transdutoes de 45 kHz e a realização de ensaios físicos e mecânicos propostos pela EuroMDFBoard - EMB. A avaliação desenvolveu-se em três fases distintas: 1. Na fase I foram realizados estudos exploratórios com o objetivo de verificar as características do PU sendo utilizado como adesivo para confecção de chapas de Pinus caribaea. Nesta fase foram confeccionadas chapas com 5 e 10 % de PU3070, que de acordo com a caracterização física e mecânica observou-se que as chapas apresentaram resistências compatíveis com as exigências da EMB, entretanto, a forte exalação de solvente inviabilizou seu manuseio do PU3070. 2. Na fase II foram confeccionadas chapas com fibras de Pinus caribaea e Eucalyptus grandis com uma nova síntese de adesivo, denominada neste trabalho de PU7030. A caracterização física e mecânica determinou valores de resistências compatíveis com as exigências da EMB. Entretanto, verificou-se a necessidade de se ajustar o teor de umidade a temperatura e a pressão de prensagem. 3. Na fase III novas chapas foram confeccionadas com fibras de Pinus caribea e Eucalyptus grandis modificando-se o teor de umidade, a temperatura e a pressão de prensagem. Com o resultado da caracterização física e mecânica, observou-se que as alterações nas umidades, temperatura e pressão de prensagem propiciaram resistências compatíveis com a EMB, com vantagens de utilização de menores teores de PU7030 e diminuição na temperatura de prensagem, representando economia no consumo de energia. Outro aspecto muito importante estudado neste trabalho foi a caracterização das chapas utilizando ensaios não-destrutivos. Neste caso foram realizadas medições, por meio de equipamento de ultra-som, utilizando-se transdutores de faces exponenciais e planas aplicados nas direções x, y e z das chapas. A partir das medições dos tempos de propagação das ondas ultra-sônicas determinaram-se as velocidades das ondas e as constantes dinâmicas das chapas. Estas variáveis foram comparadas com as propriedades de resistência das chapas obtidas nos ensaios estáticos. Em seguida desenvolveu-se análise estatística buscando-se avaliar as correlações entre os resultados de ensaios não-destrutivos e destrutivos tendo sido possível concluir que a utilização dos métodos de ensaios não-destrutivos é viável para inferir sobre as propriedades físicas e mecânicas das chapas. Com relação à utilização da PU7030, concluiu-se que essa poliuretana possibilita a substituição da resina fenólica na confecção das chapas MDF / Abstract: While employing low cost reforestation lumber, the technologies of the fabrication of fiber plates denominated ¿Medium Density Fiberboard¿ (MDF) offer to several industrial sectors the opportunity to aggregate worth to species with little or no commercial interest, opening to them the possibility of promising profitable investments. However, the phenolic resins used in the production of MDF plates are well-known pollutants to the environment and therefore harmful to the human beings in such a way that environmentally friendly alternatives have been eagerly sought. According to that, the present work has been aimed to evaluate the physical, chemical and mechanical properties of MDF manufactured with Polyurethane Adhesive (PU) derived from Castor Oil, due to the low toxicity and to the non-polluting characteristics of the resulting adhesive. The characterization of the plates has been accomplished with the help of Steinkamp BP7 ultrasonic equipment using 45 kHz transducers and the physical and mechanical tests recommended by Euro MDF Board - EMB. The work has been developed along three distinct phases. Initially a better understanding of the characteristics of the polyurethane adhesive derived from castor oil has been acquired. It has been learnt that the adhesive exhibits the main characteristic of a monocomponent synthesis, stabilized by air humidity. During that phase, plates with 5% and 10% of polyurethane adhesive have been manufactured, called Adhesive PU3070 in this work, corresponding to 30% of solids and 70% of solvents. The properties of the plates manufactured with this synthesis have been determined and it has been found that although they have met EMB demands, the strong exhalation of solvent has ruled out its usage for MDF manufacture. As for the second phase, fiber plates have been produced with a new synthesis, called Adhesive PU7030, that is, 70% of solids and 30% of solvents. Again mechanical properties have satisfied EMB regulations. However, during the tests, it has been noticed that in order to control the quality of the final product, a fine adjusting to the values of some important Variables in the manufacture process, such as humidity level, temperature and pressing pressure, would be necessary. Accordingly, in the last phase, using Pinus caribea as fiber material, three experimental conditions have been elaborated, one for each controlled Variable, and repeated again for Eucalyptus gandis. Resulting from the adjusting of the variables, it has been observed that during the manufacture process, plates using much less adhesive than the former standards still have satisfied EMB demands fully, with advantages of a significant decrease in the pressing temperature and the corresponding energy savings. The characterization of the plates using non-destructive tests has been an important feature of the present work. Measurements have been performed in the plates by means of ultrasound equipment, using exponential as well as plane face transducers. From the readings, the propagation times of the ultrasonic waves have been evaluated, allowing to the determination of the propagation velocity of the ultrasonic waves through the material and consequently its dynamic parameters, which have been correlated to the mechanical properties of the plates, by means of a suitable statistic model. It has been concluded from the results that non-destructive test methods could as well be employed for the characterization of the physical and mechanical properties of the plates / Doutorado / Construções Rurais / Doutor em Engenharia Agrícola

Ensaios não destrutivos são testes que não causam danos a estrutura ensaiada, o que os torna um excelente auxílio aos métodos de ensaios tradicionais quando estes apresentam alguma dificuldade de serem executados. Desta forma, este trabalho visa utilizar os ensaios de esclerometria e ultrassom, dando ênfase na transmissão indireta, para determinar a resistência à compressão nas primeiras idades do concreto e possibilitar um melhor controle tecnológico do material. Para se obter a relação entre os dados experimentais não destrutivos e a resistência à compressão, foram realizados ensaios em duas etapas. A primeira etapa foi desenvolvida em corpos de prova cilíndricos e prismáticos com três traços diferentes de concreto, onde foi variado o consumo de cimento. Na segunda etapa os ensaios foram realizados em uma laje alveolar produzida em laboratório. Com os dados coletados nos ensaios foi possível determinar a relação de crescimento da resistência, do índice esclerométrico e da velocidade do pulso ultrassônico ao longo do tempo, além das correlações velocidade x resistência, velocidade x índice esclerométrico; e a correlação múltipla entre os três fatores. Com base nisto, concluiu-se que é viável ter um bom controle tecnológico da resistência do concreto a partir dos ensaios não destrutivos. Este trabalho não obteve uma equação universal que correlacionasse os parâmetros para todos os tipos de traço de concreto, porém foram obtidas correlações satisfatórias para os traços ensaiados. Desta forma, é possível afirmar que o ensaio de ultrassom, especificamente posição indireta de 30 centímetros, e a esclerometria são ferramentas possíveis de serem aplicadas como auxílio à obtenção da resistência à compressão nas primeiras idades. / Non-destructive tests are tools that do not cause damage to the evaluated structure, which is an excellent support for traditional test methods. Therefore, this work used non-destructive tests such as rebound method and ultrasound, emphasizing the indirect transmission, to determine compression strength in the early age sand enable a better technological control of the material. Two-step tests were performed to see if there is a relationship between non-destructive test data and the compressive strength. The first one was performed in specimens with three different concrete compositions, where the cement ratio was varied, where as the second was carried out in a laboratory hollow core slab. With the experimental data was possible to determine the relationship of the compression strength, rebound number and ultrasonic pulse velocity over time; as the correlations strength x velocity, velocity x rebound number; and a multiple correlation between the three tests. Based on this, it was concluded that it is possible to have a good technological control of the concrete strength from non-destructive tests. A universal equation that correlates parameters for all types of concrete compositions was not found, but satisfactory correlations were obtained for the tested concretes. In this way, it is possible to affirm that the ultrasound test, specifically indirect position of 30 centimeters, and rebound method are possible tools to be applied as aid to obtain the compression strength in the early ages.

Técnicas adequadas para quantificação de biomassa florestal têm sido demandadas devido ao grande crescimento do mercado de carbono e de aspectos relacionados às mudanças climáticas, assim, é importante desenvolver métodos de determinação e estimação da biomassa com menores custos e que apresentem estimativas confiáveis. O objetivo deste trabalho foi determinar a biomassa aérea total comparando métodos destrutivos e não destrutivos e ajustar equações alométricas para biomassa aérea total e seus componentes (biomassa do fuste e biomassa da copa) usando diferentes modelos de regressão (modelos de efeitos fixos e modelos de efeitos mistos). Para isso foi realizado um inventário selecionando sistematicamente locando 30 parcelas de 200 m2 nas áreas de floresta nativa da Fazenda Três Lagoas, localizada em Angatuba, estado de São Paulo, Brasil. Posteriormente, foram coletados indivíduos de 11 espécies nativas (as de maior frequência e maior Índice de Valor de Importância - IVI). Foi realizada uma amostragem destrutiva e a cubagem rigorosa, além de coleta de quatro discos do fuste e uma bagueta de madeira das árvores distribuídas em três classes de diâmetros e determinada a densidade básica e a biomassa. Posteriormente foram ajustados diferentes modelos de regressão linear e não linear de efeitos fixos e de efeitos mistos e escolhido o melhor modelo segundo o AIC (Critério de Akaike) e o Índice de Furnival. Quando estudada a densidade básica da madeira, o método de determinação usando bagueta é diferente dos métodos destrutivos, sendo que a densidade básica da madeira baseada na bagueta apresentou sempre a maior média. No entanto, quando a biomassa do tronco é estudada, o método não destrutivo não apresenta diferença estatística dos outros métodos de coleta destrutivos (um disco e múltiplos discos). Ainda, os métodos diretos de determinação de biomassa (volumetria e gravimetria) foram estatisticamente similares. Ao ajustar as equações para biomassa aérea, os modelos mistos foram superiores aos modelos de efeitos fixos. Modelos na escala original e modelos com função de variância não conseguiram obter um bom comportamento do resíduo, sendo os modelos com transformações em ambos os lados (logaritmo) os que obtiveram homocedasticidade. Os modelos selecionados (usando o Critério de Akaike e o Índice de Furnival) foram os modelos lineares transformados de efeitos mistos (usando espécie como variável aleatória). Quando esses modelos foram aplicados ao inventário florestal da área, a biomassa aérea total foi de 125,52 Mg.ha-.1. Conclui-se que: Os métodos volumétricos e gravimétricos para determinação de biomassa do fuste são estatisticamente iguais, e permitem o uso de técnicas não destrutivas (bagueta) para determinar a densidade básica da madeira a ser usada no cálculo da biomassa. O uso de métodos não destrutivos diminui o trabalho de campo e de laboratório, o que permite a redução de custos. Quando só a densidade básica da madeira é estudada, o método destrutivo e não destrutivo apresentam diferenças estatísticas, sendo que a bagueta apresenta a maior média de densidade básica da madeira. Quando são construídos modelos de regressão para estimação de biomassa, os modelos de efeitos mistos com a espécie como efeito aleatório apresentam um melhor AIC que os modelos de efeitos fixos. Nesta floresta os modelos com transformações de ambos os lados foram os únicos modelos que obtiveram homocedasticidade. / Adequate techniques to quantify the forest biomass have shown to be necessary due to the carbon market growth and issues related to climate change; therefore, it is important to develop less expensive biomass determination and estimation methods that provide reliable estimations. The main objective of this research was to determine the total aboveground biomass by comparing destructive and non-destructive methods and fit allometric equations for total aboveground biomass and its components (trunk biomass and crown biomass) using different regression models (fixed effects and mixed effects models). In order to do that, we inventoried 30 plots of 200 m2 in native forest areas at Três Lagoas Farm in Angatuba, Sao Paulo, Brazil. Subsequently, we collected sample trees of 11 native species (those that are more frequent and that have a higher Importance Value Index - IVi). A destructive sampling was performed in those trees and after that their volume was calculated; four discs were extracted from their trunks as well as core samples distributed in three diameter classes; and, basic density and biomass were determined. Then, we fitted different linear and non-linear models of regression of fixed and mixed effects and then we chose the best model according to AIC (Akaike Information Criterion) and Furnival\'s Index. When studying wood basic density the core sample method differs from other types of methods and presents the higher mean value. However, when analyzing trunk biomass this non-destructive method does not differ statistically from other sampling destructive methods like disc and multiple discs. Nevertheless, direct methods to determine biomass (volumetry and gravimetry) were statistically similar. When fitting equations for aboveground biomass, mixed models had a superior behavior compared with fixed effects. Models in their original scale and models with variance function did not have good residuals behavior. Two-side transformation models (logarithm) showed homoscedasticity. The selected models (using Akaike Criteria and Furnival´s Index) were linear transformed models of mixed effects (using the species as a random variable). When those models were applied to the forest inventory of the area, the value corresponding to total aboveground biomass was 125.52 Mg.ha-1. Therefore, we were able to conclude that: Volumetric and gravimetric methods to determine trunk biomass are statistically equal, and allow the use of non-destructive techniques (core sampling) to determine the wood basic density if this variable is going to be used to determine biomass. The use of non-destructive methods decreases field and lab work, allowing cost reduction. When wood basic density is the only variable, destructive and non-destructive methods showed statistic differences, being that the core sample presented the highest mean of wood basic density. When adjusting regression models to estimate biomass, mixed effects models with the species as a random effect showed a better AIC compared to fixed effects models. In this forest, models with two-side transformations were the only models to obtain homoscedasticity.

O suicídio é uma morte repentina e violenta, que choca. Pode provocar indignação, pois causa em quem ficou um hiato, em relação à experiência de dizer adeus àquele que é amado. A morte autoinfligida causa sofrimento e, por isso, o enlutado por suicídio é reconhecido como sobrevivente. Este estudo teve como objetivo a compreensão do processo de luto do(a) filho(a) da pessoa que cometeu o suicídio. Jamison (2010), Alvarez (1999) e Shneidman (1985; 1993) foram os principais autores que fundamentaram a discussão sobre o suicídio. As obras de Parkes (1998; 2009), Franco (2002; 2010), Kovács (1992; 2003) e Clark (2001; 2007), as fontes básicas consultadas para a compreensão do processo de luto. Trata-se de pesquisa de natureza qualitativa, tendo como participantes 9 (nove) filhos de indivíduos que cometeram o suicídio. Os princípios éticos de sigilo, privacidade, confidencialidade, não identificação dos dados do colaborador e liberdade de participação foram respeitados. Os depoimentos foram gravados com a anuência dos entrevistados e realizados: entrevista para a coleta de depoimento, de aproximadamente 3 (três) horas de duração e 2 (dois) contatos por e-mail para enviar a transcrição das entrevistas, e outro, depois da análise dos dados, para compartilhar com o colaborador a compreensão da pesquisadora. As unidades de significados foram extraídas conforme o método fenomenológico (Moustakas, 1994) e compreendidas pela perspectiva da abordagem da Gestalt-terapia. Observou-se que para alguns entrevistados, a superação da falta do progenitor trouxe ambivalências: vivos, foram ausentes; mortos, tornaram-se presentes. O ato suicida pode denunciar uma dinâmica familiar cujo rompimento de vínculos já acontecia, ou seja, o estresse foi experienciado antes, durante e depois do suicídio. Portanto, o suicídio não foi fator precipitante, mas, sim, o processo como um todo. Quando o filho sobrevive ao suicídio de um dos genitores pode ter uma experiência cujo sofrimento provoca culpa, raiva, ressentimentos, sensação de desamparo e de abandono, solidão, falta de oportunidade por não ter recebido colo, acalanto, cuidado, amor e direção. Considerou-se que, embora a morte seja para sempre, o luto é um processo dinâmico, no qual os enlutados tentam administrar uma diversidade de sentimentos e pensamentos: além da necessidade de compreender a morte, surge a redefinição de seu papel na família. Destaca-se também o calar e o isolamento dos depoentes. O isolamento parece acontecer para que não sejam mobilizados os sentimentos confusos e não compartilhados, que ameaçam a zona de conforto tão arduamente conquistada pelos que sobreviveram. O que se cala é o sofrimento, a dúvida e o estigma. Identificou-se que o suicídio parental é uma vivência ímpar, que permite à pessoa descobrir e desenvolver estratégias de enfrentamento em seu processo de luto / Suicide is a sudden and violent death, which shocks. It may cause outrage, as it causes a gap in those who remained, in relation to the experience of saying goodbye to the one who is loved. The self-inflicted death causes suffering and, thus, the bereaved by suicide is recognized as a survivor. This study had as goal the comprehension of the grieving process of the offspring of the person who committed suicide. Jamison (2010), Alvarez (1999) and Shneidman (1985; 1993) were the main authors who grounded the discussion about suicide. The works of Parkes (1998; 2009), Franco (2002; 2010), Kovács (1992; 2003) and Clark (2001; 2007), the basic sources consulted to the comprehension of the grieving process. It is a research of qualitative nature, having as participants nine (9) offspring of individuals who committed suicide. The ethical principles of secrecy, privacy, confidentiality, no identification of the data of the collaborators and freedom of participation were respected. The testimonies were recorded with the consent of the interviewees and carried out: interview - to collect the testimony, approximately three (3) hours long - and two (2) contacts by e-mail one to send the transcripts of the interviews, and other after analyzing the data, to share with the collaborator the comprehension of the researcher. The units of meaning were extracted according to the phenomenological method (Moustakas, 1994) and understood through the perspective of the Gestalt-Therapy approach. It was observed that for some interviewees, overcoming the lack of a parent brought ambivalences: as alive, they were absent; as dead, they became present. The suicidal act may denounce a family dynamic in which breaking of bonds has already happened, in other words, the stress was experienced before, during and after the suicide. Therefore, suicide was not a triggering factor, but, instead, the process as a whole. When the child survives the suicide of one of its parents, one can have an experience whose suffering causes guilt, anger, resentment, helplessness and abandonment, loneliness, lack of opportunity by not having received lap time, soothing, care, love and guidance. It was considered that, although death is forever, grief is a dynamic process, in which bereaved ones try to manage a diversity of feelings and thoughts: besides the necessity of comprehending death, comes the redefinition of their role in the family. Also noteworthy is the silence and isolation of the deponents. The isolation seems to happen for mixed and not shared feelings not to be mobilized, that threaten the comfort zone so hardly conquered by those who survived. What is silenced is the suffering, the doubt and the stigma. It was identified that parental suicide is a unique experience that allows the person to discover and develop coping strategies in their grieving process

O presente trabalho objetivou desenvolver e implementar, em escala laboratorial, uma rotina experimental com base em Imageamento por Ressonância Magnética Nuclear (IRMN) de modo a verificar seu potencial como metodologia não-destrutiva aplicável à inspeção quali- e quantitativa de água e hidrocarbonetos líquidos aprisionados no interior de células de núcleos-colméia utilizados na confecção de painéis-sanduíche compósitos estruturais de grau aeronáutico. Tentativas foram também realizadas no sentido de se observarem e caracterizarem danos por amassamento de núcleos-colméia, assim como de se detectar a presença de resina polimérica na forma sólida, visando, desta feita, verificar o uso do IRMN na inspeção de componentes previamente reparados e/ou contendo excesso de resina por falha do processo de manufatura. Concluiu-se que IRMN é uma poderosa ferramenta para a detecção e a quantificação de líquidos puros e compostos, ricos em hidrogênio, contidos nas células de núcleos de amostras extraídas de painéis-sanduíche compósitos. O potencial do IRMN na identificação, e, portanto, na discriminação entre os diversos fluidos se mostrou bastante promissor, desde que se empreguem ferramentas de processamento e análise computadorizada de imagens a partir de programas computacionais de reconhecimento de padrões via redes neurais artificiais e/ou sistemas com base em conhecimento. A técnica de IRMN utilizada neste estudo não permitiu a captura de imagens de resina polimérica sólida, nem mesmo quando à esta foram adicionadas cargas de elementos intensificadores de sinais de RMN, tais como ferro e gadolíneo. Danos no núcleo-colméia tão pequenos quanto 1,0 mm de profundidade e 1,8 mm de diâmetro foram clara e inequivocamente imageados e delineados pela técnica IRMN, desde que estivessem permeados por fluido hidrogenado (ex. água). A quantificação de líquidos nos núcleos-colméia por intermédio de ferramentas computacionais simples (processadores e analisadores de imagens) foi muito bem sucedida no caso dos líquidos com relativamente alto ponto de fulgor, pois as massas fluidas se mantiveram constantes por períodos de tempo significativamente longos no interior das células analisadas. / This work intended to develop and implement in laboratorial scale an experimental routine funded in Nuclear Magnetic Resonance Imaging (NMRI) in order to verify its potential as a non-destructive methodology for quali- and quantitative inspection of liquid water and hydrocarbons entrapped in honeycomb core cells utilized to build up aeronautical grade structural composite sandwich panels. Attempts were also carried out to observe and characterize crush damage of honeycomb core, as well as to detect solid polymer resin towards the use of NMRI to assess previously repaired components and/or containing in excess resin amount due to manufacturing process faults. It has been concluded that NMRI is a powerful tool in detecting and quantifying hydrogen-rich pure and compound liquids contained in core cells of composite sandwich samples. The NMRI potential in identifying and, therefore, discriminating several fluids has shown very promising as long as computed image processing and analysis tools are employed from pattern recognition software via artificial neural networks and/or knowledge-based systems. The utilized NMRI technique failed in imaging solid polymer resin, even when the latter was loaded with NMR-signal intensifier elements such as iron and gadolinium. Honeycomb core damages as small as 1.0 mm in depth and 1.8 mm in diameter were clearly and unambiguously imaged and delineated by the NMRI technique since they were permeated with hydrogenated fluid (ex., water). The quantification of liquids in honeycomb cores by means of simple computational tools (image processor and analyzer) was very successful in case of relatively high flash point fluids, insofar as their masses remained constant within the analyzed cells for significantly long periods of time.

Abstract Barkhausen noise measurement is an intriguing non-destructive testing method suitable for ferromagnetic materials. It is based on the stochastic movements of magnetic domain walls when the tested sample is placed in an external varying magnetic field. Barkhausen noise is typically utilised so that some features are calculated from the signal and then compared with the studied material properties. Typical features are, for example, the root-mean-square value (RMS), peak height, width and position. Better utilisation of the method, however, requires quantitative predictions of material properties. The aim of this thesis is to study and select a suitable methodology for the quantitative prediction of material properties based on Barkhausen noise measurement. The prediction considered is divided into four steps: feature generation, feature selection, model identification and model validation. In feature generation, a large set of features is calculated with different mathematical procedures. This feature set is explored in the feature selection step to find the most significant features in terms of predictions. A model with the selected features is identified and some independent data are usually used for model validation. This thesis presents the developed procedures required in feature generation and the results of the studies using different feature selection strategies and modelling techniques. The studied feature selection methods are forward selection, simulated annealing and genetic algorithms. In addition, two-step algorithms are investigated where a pre-selection step is used before the actual selection. The modelling techniques used are multivariable linear regression, partial least squares regression, principal component regression and artificial neural networks. The studies also consider the use and effect of different objective functions. The results of the studies show that the proposed modelling scheme can be used for the prediction task. The models identified mainly include reasonable terms and the prediction accuracy is fairly good considering the challenge. However, the application of Barkhausen noise measurement is very case-dependent and thus conflicts may occur. Furthermore, the changes in unmeasured material properties may lead to the unexpected behaviour of some features. The results show that linear models are adequate for capturing the major interactions between material properties and Barkhausen noise but indicate that the use of neural networks would lead to better model performance. The results also show that genetic algorithms give better selection results but at the expense of the computational cost. / Tiivistelmä Barkhausen-kohina-mittaus on ferromagneettisille materiaaleille soveltuva materiaalia rikkomaton testausmenetelmä. Mittaus perustuu magneettisten alueiden välisten rajapintojen stokastisiin liikkeisiin, kun testattava kappale asetetaan vaihtuvaan magneettikenttään. Tyypillisesti Barkhausen-kohina-mittaussignaalista lasketaan piirteitä, joita sitten verrataan tutkittaviin materiaaliominaisuuksiin. Usein käytettyjä piirteitä ovat signaalin keskineliön neliöjuuri (RMS-arvo) sekä piikin korkeus, leveys ja paikka. Menetelmää voidaan soveltaa paremmin, jos tutkittavia materiaaliominaisuuksia voidaan ennustaa kvantitatiivisesti. Tämän tutkimuksen tavoitteena on tutkia ja valita menetelmiä, jotka soveltuvat materiaaliominaisuuksien kvantitatiiviseen ennustamiseen Barkhausen-kohina-mittauksen perusteella. Ennustusmallit luodaan neljässä vaiheessa: piirteiden laskenta, piirteiden valinta, mallin identifiointi ja mallin validointi. Piirteiden laskennassa yhdistellään erilaisia matemaattisia laskutoimituksia, joista tuloksena saadaan suuri joukko erilaisia piirteitä. Tästä joukosta valitaan ennustukseen soveltuvimmat piirteiden valinta -vaiheessa. Tämän jälkeen ennustusmalli identifioidaan ja viimeisessä vaiheessa sen toimivuus todennetaan riippumattomalla testausaineistolla. Väitöskirjassa esitetään piirteiden laskentaan kehitettyjä algoritmeja sekä mallinnustuloksia käytettäessä erilaisia piirteiden valintamenetelmiä ja mallinnustekniikoita. Tutkitut valintamenetelmät ovat eteenpäin valinta, taaksepäin eliminointi, simuloitu jäähtyminen ja geneettiset algoritmit. Väitöskirjassa esitellään myös kaksivaiheisia valintamenettelyjä, joissa ennen varsinaista piirteiden valintaa suoritetaan esivalinta. Käytetyt mallinnustekniikat ovat monimuuttujaregressio, osittainen pienimmän neliösumman regressio, pääkomponenttiregressio ja neuroverkot. Tarkasteluissa huomioidaan myös erilaisten kustannusfunktioiden vaikutukset. Esitetyt tulokset osoittavat, että käytetyt menetelmät soveltuvat materiaaliominaisuuksien kvantitatiiviseen ennustamiseen. Identifioidut mallit sisältävät pääasiassa perusteltavia termejä ja mallinnustarkkuus on tyydyttävä. Barkhausen-kohina-mittaus on kuitenkin erittäin tapauskohtainen ja täten ristiriitoja kirjallisuuden kanssa voidaan joskus havaita. Näihin ristiriitoihin vaikuttavat myös ei-mitattavat muutokset materiaaliominaisuuksissa. Esitetyt tulokset osoittavat, että lineaariset mallit kykenevät ennustamaan suurimmat vuorovaikutukset materiaaliominaisuuksien ja Barkhausen-kohinan välillä. Tulokset kuitenkin viittaavat siihen, että neuroverkoilla päästäisiin vielä parempiin mallinnustuloksiin. Tulokset osoittavat myös, että geneettiset algoritmit toimivat piirteiden valinnassa paremmin kuin muut tutkitut menetelmät.

L’objectif de cette thèse était de concevoir, fabriquer, et tester des transducteurs ultrasonores multi – éléments pour des applications en environnements sévères. Dans ce contexte, des techniques de caractérisation des matériaux ont été développées afin d’adapter la conception des transducteurs en fonction des contraintes de l’environnement, et plus particulièrement la température. Deux types de conceptions ont été étudiées selon les applications visées : La première application consistait à développer un transducteur ultrasonore permettant de réaliser des contrôles non destructifs dans des réacteurs de génération IV (refroidi au sodium liquide) lors d’un arrêt de tranche. Dans ce cas, l’environnement sévère était caractérisé par une température de 200 °C, et la présence de sodium liquide. Des radiations pouvaient également être présentes. Pour cette application, un transducteur (nommé LiNa) sous la forme d’un projecteur ultrasonore linéaire de 20 éléments, fonctionnant à 2.5MHz a été fabriquée, puis testé en eau et en sodium liquide. La seconde application consistait à développer un transducteur ultrasonore permettant de réaliser des contrôles non destructifs en contact de pièces massives en cours de soudage. Une pièce massive est par exemple une cuve de réacteur nucléaire. Ce transducteur permet de détecter des défauts dans une soudure très rapidement après sa réalisation, et ainsi corriger directement cette dernière, sans attendre que les pièces soient refroidies. Pourcette application, un transducteur (nommé MaCo) sous forme de matrice 8 × 8 éléments, fonctionnant à 5MHz a été développé, et caractérisé de la température ambiante, jusqu’à 240 °C. Avec ce capteur, Avec ce capteur, des échos en ondes transversales ont été obtenus jusqu’à la température limite, sans refroidissement. / The goal of this thesis was to design, fabricate and test phased arrays ultrasonic transducers for harshenvironment applications. In this context, characterization methods were developed in order to adapt transducerdesign to the environment. We designed two types of ultrasonic phased array transducers according to theconsidered application:The first application aimed at developping an ultrasonic transducer for non destructive testing in IVth generationnuclear reactors (cooled with liquid sodium) during reactor outages. In this case, the harsh environment wascharacterized by a temperature of 200 °C, and the presence of liquid sodium. Radiations could also be present.For this application, a 20 elements 2.5MHz immersion linear projector (called LiNa) was fabricated then testedunder water and under liquid sodium.The second application aimed at developping an ultrasonic transducer in order to realize non destructive testingin contact with massive pieces during welding. A massive piece for example is a tank for nuclear plant reactor.The transducer will permit to quickly detect defects in a weld after its realization, and then correct it directlyif necessary, without waiting for the pieces to cool down at ambient temperatures. For this application,a 64elements 5MHz matrix transducer (named MaCo) were developed and tested from ambient to 240 °C. Thetransducer worked up to the limit temperature without any cooling system, and some typical defects weredetected.

The forecast of the next upcoming years estimates a growth of demand in transport. As the railway sector in Europe has developed over many years, the infrastructure presents performance issues because of, among other factors, asset maintenance activities being difficult and time consuming. There are currently 4000 railway bridges in Sweden managed by Trafikverket which are submitted to inspections at least every six years. The most common survey is done visually to determine the physical and functional condition of the bridges as well as finding damages that may exist on them. Because visual inspection is a subjective evaluation technique, the results of these bridge inspections may vary from inspector to inspector. The data collection is time consuming and written in standard inspection reports which may not provide sufficient visualization of damages. The inspector also needs to move around the bridge at close distance which could lead to unsafe working conditions. 3D modelling technology is becoming more and more common. Methods such as Close Ranged Photogrammetry (CRP) and Terrestrial Laser Scanning (TLS) are starting to be used for architecture and heritage preservation as well as engineering applications. Infrared (IR) scanning is also showing potential in creating 3D models but has yet not been used for structural analysis and inspections. A result from these methods is a point cloud, a 3D representation of a model in points that can be used for creating as-built Building Information Modeling (BIM)-models. In this study, the authors put these three methods to test to see if IR scanning and CRP are suitable ways, such as TLS is, to gather data for 3D-reconstruction of concrete railway bridges in fast, safe and non-disturbing ways. For this, the three technologies are performed on six bridges chosen by Trafikverket. The further aim is to determine if the 3D-reconstructions can be used for acquiring BIM-information to, among other things, create as-built drawings and to perform structural evaluations. As a result from the study, IR scanning and CRP show great potential as well as TLS in 3D-reconstruction of concrete railway bridges in fast, safe and non-disturbing ways. Still, there is a need of development regarding the technologies before we can start to rely on them completely.

Albert Bandura’s construct of moral disengagement has been recognized as theoretically useful for the study of self-destructive behaviors and moral disengagement, and to provide a unique criterion for empirical investigation of United States combat veterans returning from the wars in Iraq and Afghanistan. The purpose of this project is to better understand predictors related to the disengagement of moral self-sanctions in order that self-destructive behaviors related to Post Traumatic Stress Disorder, such as drug and alcohol abuse, and the ultimate self-destructive behavior of suicide, might be mitigated. Charles Snyder’s hope construct, Harold Koenig and Arndt Büssing’s concept of intrinsic religiosity and Corey Keyes’ notion of psychological flourishing are chosen as viable predictor variables. Hope and intrinsic religiosity are found to be significant and to be correlated with moral disengagement. Inferences regarding the results are postulated and suggestions are made for research regarding other possible predictors of moral disengagement. Agentive moral reinforcement is discussed and proposals offered related to increasing psychological resilience and decreasing the agent’s risk associated with moral disengagement.

Les matériaux composites sont largement utilisés dans l'industrie en raison de leur bonne tenue mécanique et de leur faible densité. La diversité des domaines d’application des matériaux composites donne lieu à une grande variété de modes de sollicitation et d’endommagement. De ce fait, l’évaluation de leurs propriétés et le contrôle de leur état présentent un grand intérêt industriel. Dans ce travail, une nouvelle méthode d’évaluation et de contrôle non destructif dite par sonothermographie est explorée. Cette méthode est basée sur l'analyse du champ thermique induit par des ondes ultrasonores de puissance dans les matériaux absorbants tels que les composites. Deux applications complémentaires sont étudiées, d’une part l’évaluation des propriétés thermiques du matériau et d’autre part le contrôle non destructif de structures par thermographie infrarouge. Dans ce cadre, le problème direct de la sonothermographie est résolu numériquement à partir d’un modèle par éléments finis. Ce modèle permet de simuler le champ thermique induit par la propagation d’ondes ultrasonores dans un matériau absorbant dont les propriétés sont connues. Les simulations réalisées permettent de montrer l’applicabilité de la sonothermographie à la détection de défauts. Une nouvelle approche de caractérisation thermique est également développée. Cette approche basée sur la formulation faible de l’équation de conduction de la chaleur permet une estimation robuste de la diffusivité thermique du matériau à partir du champ thermique induit par les ondes ultrasonores de puissance. Des résultats expérimentaux sont présentés pour le cas de plaques minces. / The composite materials are widely used in industry because of their high mechanical resistance and low density. The diversity of composite materials application fields gives rise to a large variety of solicitation and damage conditions. For this reason, the evaluation of their properties and their health monitoring are of great industrial interest. In this work, a new method of evaluation and non-destructive testing named sonothermography is explored. This method is based on the analysis of thermal fields induced by ultrasonic waves in absorbent materials such as composites. Two additional applications are studied: the evaluation of the thermal properties of the material and the non-destructive testing of structures by infrared thermography. In this framework, the direct problem of sonothermography is solved numerically using a model based on the finite element method. This model allows to simulate the thermal field induced by the propagation of ultrasonic waves in absorbent material whose properties are known. The simulations carried out show the applicability of the sonothermography for the detection of defects. An innovative approach for thermal characterization is also developed. This approach based on the weak formulation of the heat conduction equation allows a robust estimate of the thermal diffusivity of the material from the thermal field induced by ultrasonic waves. Experimental results are presented for thin plates.