The main motivation of this thesis is to explore several techniques for estimating electric guitar synthesis parameters to replicate the sound of popular guitarists. Many famous guitar players are recognisable by their distinctive electric guitar tone, and guitar enthusiasts would like to play or obtain their favourite guitarist's sound on their own guitars. This thesis starts by exploring the possibilities of replicating a target guitar sound, given an input guitar signal, using a digital filter. A preliminary step is taken where a technique is proposed to transform the sound of a pickup into another on the same electric guitar. A least squares estimator is used to obtain the coefficients of a finite impulse response (FIR) filter to transform the sound. The technique yields good results which are supported by a listening test and a spectral distance measure showing that up to 99% of the difference between input and target signals is reduced. The robustness of the filters towards changes in repetitions, plucking positions, dynamics and fret positions are also discussed. A small increase in error was observed for different repetitions; moderate errors arose when the plucking position and dynamic were varied; and there were large errors when the training and test data comprised different notes (fret positions). Secondly, this thesis explored another possible way to replicate the sound of popular guitarists in order to overcome the limitations provided by the first approach. Instead of directly morphing one sound into another, replicating the sound with electric guitar synthesis provides flexibility that requires some parameters. Three approaches to estimate the pickup and plucking positions of an electric guitar are discussed in this thesis which are the Spectral Peaks (SP), Autocorrelation of Spectral Peaks (AC-SP) and Log-correlation of Spectral Peaks (LC-SP) methods. LC-SP produces the best results with faster computation, where the median absolute errors for pickup and plucking position estimates are 1.97 mm and 2.73 mm respectively using single pickup data and the errors increased slightly for mixed pickup data. LC-SP is also shown to be robust towards changes in plucking dynamics and fret positions, where the median absolute errors for pickup and plucking position estimates are less than 4 mm. The Polynomial Regression Spectral Flattening (PRSF) method is introduced to compensate the effects of guitar effects, amplifiers, loudspeakers and microphones. The accuracy of the estimates is then tested on several guitar signal chains, where the median absolute errors for pickup and plucking position estimates range from 2.04 mm to 7.83 mm and 2.98 mm to 27.81 mm respectively.

Nanopartículas (NPs) que apresentam ressonância plasmon de superfície localizada (RPSL) são aplicáveis em diversas áreas como, por exemplo, em terapia e diagnóstico na área biomédica. Estudos e aplicações in vivo requerem que a banda plasmon (BP) ocorra na mesma região da janela terapêutica, entre 600 e 1000 nm. Esta condição pode ser atingida com a modulação da BP pelo controle da morfologia e da composição química das NPs. Os objetivos principais deste trabalho foram estudar métodos de síntese que permitissem obter maiores quantidades de materiais quando comparados aos métodos convencionais em meio aquoso, e conjuntamente avaliar os parâmetros de síntese para obter NPs com diferentes morfologias e composições almejando modular a BP para região de interesse. Obteve-se nanoesferas (NEs) de Au monodispersas com diâmetro médio de 9 nm por redução com oleilamina em solução concentrada de sais de ouro. Dispersibilidade em água com elevada estabilidade coloidal foi alcançada via um procedimento de troca de ligantes, substituindo as moléculas de oleilamina, presentes na superfície das NPs assim como sintetizadas, por moléculas de ácido 11-mecaptoundecanóico. Nanobastões (NBs) de Au (largura de 12 nm) com diferentes comprimentos (30-300 nm) foram obtidos em misturas incomuns das fases cristalinas fcc e hcp. Estes NBs apresentam duas BP no espectro UV-Vis-NIR, uma em 520 nm e outra banda alargada a partir de 800 nm atribuídas à RPSL transversal e longitudinal, respectivamente. Inicialmente, os NBs foram sintetizados utilizando oleilamina como agente redutor e surfactante, sendo posteriormente avaliado que a presença de álcool oleico ou trietilamina no meio mantiveram uma condição de crescimento-1D mantendo a forma dos nanomateriais. NEs de Ag foram obtidas em condições semelhantes às NEs de Au com a BP em torno de 420 nm. Obteve-se misturas de NEs e NBs de AuCu3 (NBs, com razão de aspecto de 3) em todas as condições estudadas, sendo posteriormente separadas. Duas BP foram observadas para os NBs de AuCu3 em 560 e 766 nm, atribuídas à ressonância transversal e longitudinal, respectivamente. NPs monodispersas de Cu1,8S com 10 nm e BP centradas em 1150 nm foram sintetizadas por injeção a quente. Uma tentativa de recobrimento com Au das NPs de Cu1,8S resultou em uma reação de substituição, formando NPs de Au2S, a qual não apresentou BP. Investigou-se sínteses de NPs Cu1,8S dopado com M (M = Fe, Al e Zn) e alguns resultados foram: i) todas amostras foram obtidas na fase digenita e com baixa dispersão de tamanho; ii) Al e Fe incorporaram na estrutura cristalina, mas aparentemente o Zn não incorporou; iii) a BP foi deslocada para maiores comprimentos de ondas em todas amostras. Em resumo, obteve-se NPs com BP na região de interesse, em quantidades maiores que as sínteses convencionais. Este trabalho contribui para a compreensão da ação de reagentes/condições experimentais sobre a composição e o controle morfológico das NPs (principalmente crescimento-1D). Ressalta-se, entre os estudos, a formação de NBs de Au na fase hcp, possibilitando futuros estudos de propriedades; o redshift da BP das NPs de Cu1,8S dopados que não eram esperados, sendo um resultado instigante para futuros estudos; e a efetiva modificação de superfície das NPs de Au que resultou em elevada estabilidade coloidal na faixa de pH entre 6 e 10, possibilitando futuras aplicações. / Nanoparticles (NPs) that present localized surface plasmon resonance (LSPR) enables several applications, for example, therapy and diagnosis in the biomedical area. In vivo studies and applications require that plasmon band occurs in the same region of the therapeutic window, between 600 and 1000 nm. This condition can be achieved with the plasmon band (PB) modulation by morphological and chemical composition control of the NPs. The main purpose of this work concerning to evaluate of the syntheses parameters to obtain NPs with different morphologies and compositions by using experimental procedures, which to enable reach larger NPs amounts than the conventional aqueous medium methods. Monodisperse Au nanospheres (NSs) with average diameter of 9 nm were obtained by reduction of gold salts in concentrated solutions by oleylamine. As-synthesized Au-NSs present oleylamine molecules onto the surface that it was replaced by 11-mercaptoundecanoic acid by using a ligand exchange procedure, resulting in the water-dispersible system with high colloidal stability. Au nanorods (NRs, 12 nm-width) with different lengths (30-300 nm) were synthesized. These NRs are an expressive result, because its present an unusual fcc and hcp crystalline phases mixtures. There is only one paper in the literature that reports the direct synthesis of Au-hcp nanostructure. The NRs dispersion show two PB in the UV-Vis-NIR spectrum at 520 nm and another large band starting in 800 nm attributed to transversal and longitudinal LSPR, respectively. Initially, the NRs were synthetized by using oleylamine as reducing agent and surfactant, and NPs with same shape were obtained in presence of oleyl alcohol or triethylamine as surfactant in the medium. Ag NSs were obtained in similar conditions of Au NSs with shape control, and LSPR band in 420 nm. Mixtures of NSs and NRs (aspect ratio of 3) of AuCu3 were obtained for all studied conditions, and separated by using a selective separation process. Two PB were observed for AuCu3 NRs at 560 and 766 nm, assigned to transversal and longitudinal resonance, respectively. Monodisperse Cu1,8S semiconductor NSs with 10 nm and PB centered in 1150 nm were synthetized via hot-injection, and attempts to cover them with Au resulted in a substitution reaction that lead the formation of Au2S NPs, which did not present PB. Syntheses of M-doped Cu1,8S NPs (M = Fe, Al e Zn) were investigated and some results were: i) all samples are digenite phase and presented low dispersivity of size; ii) Al and Fe were incorporate more effective into the crystal structure than Zn; iii) were observed redshift of PB for all samples. In summary, NPs with PB in the region of interest were obtained in greater amounts than the conventional syntheses. This thesis presents contributions to the understanding of experimental parameters that act on the compositional and morphological control of NPs (mainly 1D growth). It is emphasized among the studies: the formation of Au NRs in the hcp phase, enabling future studies of properties; the PB redshift of the doped Cu1,8S NPs that were not expected, however, this is a stimulating result for future studies; and an effective surface modification of the Au NPs that result in high colloidal stability in the pH range between 6 and 10, allowing for future applications.

Nanopartículas (NPs) que apresentam ressonância plasmon de superfície localizada (RPSL) são aplicáveis em diversas áreas como, por exemplo, em terapia e diagnóstico na área biomédica. Estudos e aplicações in vivo requerem que a banda plasmon (BP) ocorra na mesma região da janela terapêutica, entre 600 e 1000 nm. Esta condição pode ser atingida com a modulação da BP pelo controle da morfologia e da composição química das NPs. Os objetivos principais deste trabalho foram estudar métodos de síntese que permitissem obter maiores quantidades de materiais quando comparados aos métodos convencionais em meio aquoso, e conjuntamente avaliar os parâmetros de síntese para obter NPs com diferentes morfologias e composições almejando modular a BP para região de interesse. Obteve-se nanoesferas (NEs) de Au monodispersas com diâmetro médio de 9 nm por redução com oleilamina em solução concentrada de sais de ouro. Dispersibilidade em água com elevada estabilidade coloidal foi alcançada via um procedimento de troca de ligantes, substituindo as moléculas de oleilamina, presentes na superfície das NPs assim como sintetizadas, por moléculas de ácido 11-mecaptoundecanóico. Nanobastões (NBs) de Au (largura de 12 nm) com diferentes comprimentos (30-300 nm) foram obtidos em misturas incomuns das fases cristalinas fcc e hcp. Estes NBs apresentam duas BP no espectro UV-Vis-NIR, uma em 520 nm e outra banda alargada a partir de 800 nm atribuídas à RPSL transversal e longitudinal, respectivamente. Inicialmente, os NBs foram sintetizados utilizando oleilamina como agente redutor e surfactante, sendo posteriormente avaliado que a presença de álcool oleico ou trietilamina no meio mantiveram uma condição de crescimento-1D mantendo a forma dos nanomateriais. NEs de Ag foram obtidas em condições semelhantes às NEs de Au com a BP em torno de 420 nm. Obteve-se misturas de NEs e NBs de AuCu3 (NBs, com razão de aspecto de 3) em todas as condições estudadas, sendo posteriormente separadas. Duas BP foram observadas para os NBs de AuCu3 em 560 e 766 nm, atribuídas à ressonância transversal e longitudinal, respectivamente. NPs monodispersas de Cu1,8S com 10 nm e BP centradas em 1150 nm foram sintetizadas por injeção a quente. Uma tentativa de recobrimento com Au das NPs de Cu1,8S resultou em uma reação de substituição, formando NPs de Au2S, a qual não apresentou BP. Investigou-se sínteses de NPs Cu1,8S dopado com M (M = Fe, Al e Zn) e alguns resultados foram: i) todas amostras foram obtidas na fase digenita e com baixa dispersão de tamanho; ii) Al e Fe incorporaram na estrutura cristalina, mas aparentemente o Zn não incorporou; iii) a BP foi deslocada para maiores comprimentos de ondas em todas amostras. Em resumo, obteve-se NPs com BP na região de interesse, em quantidades maiores que as sínteses convencionais. Este trabalho contribui para a compreensão da ação de reagentes/condições experimentais sobre a composição e o controle morfológico das NPs (principalmente crescimento-1D). Ressalta-se, entre os estudos, a formação de NBs de Au na fase hcp, possibilitando futuros estudos de propriedades; o redshift da BP das NPs de Cu1,8S dopados que não eram esperados, sendo um resultado instigante para futuros estudos; e a efetiva modificação de superfície das NPs de Au que resultou em elevada estabilidade coloidal na faixa de pH entre 6 e 10, possibilitando futuras aplicações. / Nanoparticles (NPs) that present localized surface plasmon resonance (LSPR) enables several applications, for example, therapy and diagnosis in the biomedical area. In vivo studies and applications require that plasmon band occurs in the same region of the therapeutic window, between 600 and 1000 nm. This condition can be achieved with the plasmon band (PB) modulation by morphological and chemical composition control of the NPs. The main purpose of this work concerning to evaluate of the syntheses parameters to obtain NPs with different morphologies and compositions by using experimental procedures, which to enable reach larger NPs amounts than the conventional aqueous medium methods. Monodisperse Au nanospheres (NSs) with average diameter of 9 nm were obtained by reduction of gold salts in concentrated solutions by oleylamine. As-synthesized Au-NSs present oleylamine molecules onto the surface that it was replaced by 11-mercaptoundecanoic acid by using a ligand exchange procedure, resulting in the water-dispersible system with high colloidal stability. Au nanorods (NRs, 12 nm-width) with different lengths (30-300 nm) were synthesized. These NRs are an expressive result, because its present an unusual fcc and hcp crystalline phases mixtures. There is only one paper in the literature that reports the direct synthesis of Au-hcp nanostructure. The NRs dispersion show two PB in the UV-Vis-NIR spectrum at 520 nm and another large band starting in 800 nm attributed to transversal and longitudinal LSPR, respectively. Initially, the NRs were synthetized by using oleylamine as reducing agent and surfactant, and NPs with same shape were obtained in presence of oleyl alcohol or triethylamine as surfactant in the medium. Ag NSs were obtained in similar conditions of Au NSs with shape control, and LSPR band in 420 nm. Mixtures of NSs and NRs (aspect ratio of 3) of AuCu3 were obtained for all studied conditions, and separated by using a selective separation process. Two PB were observed for AuCu3 NRs at 560 and 766 nm, assigned to transversal and longitudinal resonance, respectively. Monodisperse Cu1,8S semiconductor NSs with 10 nm and PB centered in 1150 nm were synthetized via hot-injection, and attempts to cover them with Au resulted in a substitution reaction that lead the formation of Au2S NPs, which did not present PB. Syntheses of M-doped Cu1,8S NPs (M = Fe, Al e Zn) were investigated and some results were: i) all samples are digenite phase and presented low dispersivity of size; ii) Al and Fe were incorporate more effective into the crystal structure than Zn; iii) were observed redshift of PB for all samples. In summary, NPs with PB in the region of interest were obtained in greater amounts than the conventional syntheses. This thesis presents contributions to the understanding of experimental parameters that act on the compositional and morphological control of NPs (mainly 1D growth). It is emphasized among the studies: the formation of Au NRs in the hcp phase, enabling future studies of properties; the PB redshift of the doped Cu1,8S NPs that were not expected, however, this is a stimulating result for future studies; and an effective surface modification of the Au NPs that result in high colloidal stability in the pH range between 6 and 10, allowing for future applications.

Les polymères de Fe(II) à transition de spin à base de ligand triazole [Fe(Rtrz)3]X2 possèdent des propriétés de commutation proches de la température ambiante. Cette bistabilité détectable à la fois par voie optique et magnétique leur confère un intérêt applicatif. Il est maintenant acquis que leurs propriétés sont très dépendantes de leur composition : la nature du substituant du ligand 1,2,4-triazole et/ou de l’anion et/ou du taux d’hydratation. Ce travail a permis d’aborder diverses problématiques. L’influence du phénomène de déshydratation/réhydratation sur les propriétés de transition de spin est d’abord étudiée pour quelques complexes. Ensuite, la synthèse de nouveaux matériaux est envisagée grâce à la méthode des alliages moléculaires. Puis, l’influence des paramètres de synthèse sur les propriétés est examinée pour quatre composés choisis. Enfin, l’effet du traitement en milieu supercritique sur les caractéristiques de ces composés moléculaires est étudié. / Spin crossover polymers based on Fe(II) and 1,2,4-triazole ligands [Fe(Rtrz)3]X2 have switching capabilities near room temperature. Optical and magnetic bistabilities observed for these systems confer potential applications. It is well established that their properties are highly dependent on their composition : the nature of the 1,2,4-triazole substituent, the anion and the rate of hydration. Our work has addressed several different topics. The influence of the dehydration/rehydration phenomenon on the spin transition is first studied for some complexes. Next, molecular alloy method is considered to obtain new materials. Then, the influence of synthesis parameters on the properties is examined for four selected compounds. Finally, the effect of treatment in a supercritical medium on the molecular characteristics of these compounds is studied.

L’influence de paramètres de synthèse et de traitements post-synthèse sur le caractère hydrophobe/hydrophile de silices mésoporeuses organisées (SMO) de type SBA-15 a été étudiée. Ainsi nous avons montré que la durée du mûrissement peut être réduite à la durée nécessaire à la précipitation. La température, l’agitation et la durée de synthèse modulent la morphologie des particules et des agrégats. Le mode de chauffage, la présence d’un sel inorganique et le rapport silice/tensioactif ont un effet sur la structure et la texture du matériau. Concernant les traitements post-synthèse, nous avons considéré l’élimination de l’agent structurant et la fonctionnalisation par greffage. Le taux de silanols diminue suite au vieillissement mais surtout après calcination : cette étape efface les différences en termes de teneur en silanols. C’est la raison pour laquelle une nouvelle méthode d’élimination du tensioactif efficace (dès 300 °C) et rapide (dès 15 min) a été mise en œuvre : la calcination à l’aide d’un four à induction conduit à un matériau avec des propriétés structurales, texturales et une teneur en silanols supérieures à celles d’une SMO de type SBA-15 calcinée par la méthode conventionnelle. La calcination par induction a également été appliquée avec succès sur différents types de SMO telles que la SBA-16 et la MCM-41. Ensuite, l’influence des caractéristiques initiales de la SMO sur la fonctionnalisation par un greffage post-synthèse a été étudiée. Une SMO de type SBA-15 plus hydrophobe a été obtenue avec un greffon possédant une seule fonction condensable. La teneur initiale et probablement l’accessibilité des silanols ont un impact significatif sur le taux de greffage. / The influence of synthesis parameters and post-synthesis treatments on the hydrophobic/hydrophilic character of SBA-15 type ordered mesoporous silicas (OMS) was studied. It was found that the duration of ripening can be reduced to the precipitation time. Temperature, stirring and duration of synthesis steps can modulate the morphology of particles and aggregates. Heating process, presence of an inorganic salt and silica/surfactant ratio are also parameters that affect the structure and texture of the material. Concerning post-synthesis treatments, the elimination of the template and the functionalization by grafting were considered. The rate of silanols decreases during aging but mostly after calcination: this step erases the differences in silanol content. This is why a new method for an effective (at 300 ° C) and fast (for 15 min) removal of the surfactant has been implemented: the calcination using an induction furnace leads to a material with structural, textural properties and silanol content greater than those of a SBA-15 material calcined by the conventional method. The calcination induction has also been successfully applied on different types of OMS such as SBA-16 and MCM-41. Then, the influence of the OMS characteristics on functionalization by post-synthesis grafting was studied. The more hydrophobic SBA-15 material was obtained with a grafting agent possessing a single condensable function. It was also observed that the initial content and the accessibility of silanols probably have a significant impact on the grafting rate.