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This study presents results of selective laser melting (SLM), powder metallurgy (PM), and casting technologies applied for producing Ti–TiB composites from Ti–TiB₂ powder. Diffraction patterns and microstructural investigations reveal that chemical reaction occurred between Ti and TiB₂ during all the three processes, leading to the formation of Ti–TiB composites. The ultimate compressive strength of SLM-processed and cast samples are 1421 and 1434 MPa, respectively, whereas the ultimate compressive strengths of PM-processed 25%, 29%, and 36% porous samples are 510, 414, and 310 MPa, respectively. The Young’s moduli of porous composite samples are 70, 45, and 23 GPa for 25%, 29%, and 36% porosity levels, respectively, and are lower than those of SLM-processed (145 GPa) and cast (142 GPa) samples. Fracture analysis of the SLM-processed and cast samples shows shear fracture and microcracks across the samples, whereas failure of porous samples occurs due to porosities and weak bonds among particles.

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Denna studie har för avsikt att analysera hur den rådande trafikplaneringen ser ut i dagens Sverige, med fokus på Stockholm. Fokus ligger på att analysera trafikplaneringens uppkomst med bilen som utgångspunkt, hur denna har bidragit till negativa externa effekter som nu på senare tid uppmärksammats och legat till grund för ökad pådrivning mot ett trafiksystem som behöver förändras mot mer hållbara transporter, likt kollektivtrafik. Genom att analysera rådande regeringsdokument mot olika plan- och visionsdokument så kan studien bidra till att ge en mer reflekterad syn över vad som görs i realiteten mot vad mer visionära mål säger. Studien sker utifrån totalt 2 teorier samt 2 begrepp som är viktiga för att förstå dagens trafikplanering och hur resebeteende kan förändras. Mot detta är det också viktigt att se vad medborgare tycker och tänker för att se om planeringen delas av allmänheten. Detta då ökad samsyn gällande frågor och åtgärder inom trafikplaneringen kan bidra till ökad effektivitet och vilja till förändrat resebeteende. Studien har ett tydligt fokus på bilen och kollektivtrafik som transportmedel.

The fast development of the tourism industry has created both positive and negative impacts on host communities. Reacting to these impacts, host residents hold various attitudes towards tourism and tourists. It has come to common agreement that a supportive host community plays a vital role in the successful and long-term development of community tourism. In order to explain the antecedents of community attitudes towards tourism, researchers have investigated the topic from both the extrinsic perspective (such as stage-based models) and the intrinsic perspective (such as the Social Exchange Theory). Nevertheless, there are still several important research gaps and deficiencies within the existing literature. First, the influence of psychological factors (personality) on attitudes towards tourism is somewhat neglected. Second, when examining the relationship between community attitudes towards tourism and the influential factors, the majority of previous studies do not distinguish the orthogonal dimensions of attitudes (such as positive dimension and negative dimension). Third, the existing literature has not addressed the issue of whether specific attitudes towards tourism will lead to a corresponding behaviour when interacting with tourists, and what other factors are determinant in host-guest interactive behaviour. Aiming to address such research gaps and deficiencies, this study has a major objective of developing a theoretical model (encompassing attitude element) to understand the antecedents of host-guest interaction. A quantitative approach was employed for the entire project. A self-administrated questionnaire survey was used to collect primary data. A total of 878 useful questionnaires were returned for analyses. Stratification sampling methods were utilized in communities where population database was accessible, while random sampling methods were used in other communities. The findings from this study confirmed the two major hypotheses in terms of community attitudes towards tourism. First, there was a significant relationship between an individual's personality and his/her attitudes towards tourism. Residents being high on Openness, Conscientiousness, Extraversion and Agreeableness traits and low on the Neuroticism trait tended to be more positive towards tourism than their counterparts. Second, while some factors were found to be influential on both positive and negative dimensions of attitudes towards tourism, others only demonstrated influences on one dimension. The Resident-Tourist Interaction Model developed in this study provided a comprehensive theoretical framework in modelling and predicting host residents' interactive behaviour towards tourists. Drawing on the evaluation results of three leading behavioural theories belonging to the school of cognition, the Model identified attitudinal, volitional, social, motivating and habitual factors for the prediction of resident-tourist interactive behaviour. Motivating factor (intention) was the critical and immediate element for action, which, in turn, was best predicted by subjective norms. External factors (gender, age and personality traits) only moderated the predictive power of the Model by less than two percent. The Model was valid and reliable for the current data. The present study advanced resident-tourist interactive behavioural study by establishing a sound theoretical framework. It also consolidated the body of knowledge in understanding community attitudes towards tourism. Findings from this study have significant practical implications for community tourism planning and management.

Le matériau composite à matrice de titane renforcée par des cristaux discontinus de monoborure de titane (TiB) constitue une classe nouvelle de matériaux destinés à des applications de haute technologie. Ces composites présentent des avantages car le procédé d'élaboration permet l'obtention de pièces de formes complexes à moindre coût par rapport aux composites à matrice titane renforcée par des filaments continus. Le procédé d'obtention de composites Ti/TiB nécessite deux étapes de fabrication: (1) au cours de la première étape un pré-composite de fraction volumique élevée en TiB est obtenu par un procédé d'autocombustion (SHS), (2) lors d'une seconde étape, ce composite est dilué dans l'alliage de titane liquide pour obtenir la fraction volumique désirée. Des composites de fraction volumique en TiB comprise entre 0 et 10% ont été élaborés puis caractérisés. La microstructure de la matrice est affinée et les performances mécaniques sont améliorées par la présence du TiB. Finalement, une étude technico-économique de ce procédé a été réalisée pour évaluer la viabilité industrielle du matériau et du procédé.

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[pt] O objetivo da dissertação é contribuir para o avanço do conhecimento sobre a importância das funções da Tecnologia Industrial Básica (TIB) no ciclo de inovação das micro, pequenas e médias empresas (MPMEs) de base tecnológica no Brasil. Reconhecendo que essas empresas têm um papel fundamental no desenvolvimento econômico e social do país, a motivação da pesquisa é responder como elas percebem a importância das funções da TIB para o ciclo de inovação, na perspectiva de ressaltar os benefícios oriundos da consolidação da infraestrutura nacional de serviços tecnológicos de apoio a MPMEs de base tecnológica. A metodologia utilizada compreende: (i) revisão bibliográfica e documental para a elaboração do referencial teórico sobre os temas centrais da dissertação: MPMEs de base tecnológica; TIB; e inovação tecnológica; (ii) definição do objeto de estudo; da fonte primária de dados – Pesquisa de Inovação Tecnológica (PINTEC) do IBGE; e da grade de análise; (iii) solicitação ao IBGE de tabulações especiais da PINTEC; recebimento, formatação e análise dos dados; e elaboração e análise dos resultados; (iv) formulação das conclusões da pesquisa e de sugestões para a próxima PINTEC e estudos futuros. Destacam-se como resultados: (i) identificação de quatro itens da PINTEC diretamente associados às funções da TIB; (ii) análise da percepção das MPMEs brasileiras de base tecnológica sobre a relevância das funções da TIB para a inovação; (iii) análise comparativa dos padrões de respostas das MPMEs de base tecnológica inovadoras e não inovadoras. Como conclusão, tais resultados permitem afirmar que, em geral, essas empresas consideram as funções da TIB relevantes para suas atividades inovativas. A comparação entre as respostas das empresas inovadoras e não inovadoras reforça essa percepção: as inovadoras percebem melhor a importância de algumas funções da TIB do que as não inovadoras. / [en] The aim of this dissertation is to contribute to the understanding of some basic infrastructural technologies (TIB acronym in Portuguese) supporting innovation of technology-based micro, small and medium size enterprises (MSMEs) in Brazil. Given the critical role played by these firms in Brazil s social and economic development, the work seeks to answer how they perceive the importance of TIB in their innovation cycle. The methodology comprises: (i) a literature survey to elaborate a theoretical outline to characterize the core subjects of the dissertation: technology-based MSMEs; TIB; and technological innovation; (ii) definition of the object of study, of the primary data source – Technological Innovation Survey (Pesquisa de Inovação Tecnológica-PINTEC), of IBGE (Brazilian Statistical Office), and the analytic framework; (iii) to request IBGE to produce special tabulations; receipt, formatting and analysis of data; and analysis of results; and (iv) formulation of conclusions and suggestions for the next PINTEC survey and for future research. The main results can be summarized as follows: (i) identification of four PINTEC items associated with some TIB functions; (ii) identification and analysis of Brazilian technology-based MSMEs perceptions of the relevance of TIB functions for supporting innovation; and (iii) comparative analysis of patterns of response of innovative and non-innovative technology-based MSMEs. As conclusion, it can be said that, in general, these firms positively respond to TIB functions in innovation cycle. In particular, results show that innovative enterprises perceived better some TIB functions than the non-innovative ones.

This work presents a systematic study of the mechanochemical processes leading to chemical reactions occurring due to effects of high-strain-rate deformation associated with uniaxial strain and uniaxial stress impact loading in highly heterogeneous metal powder-based reactive materials, specifically compacted mixtures of Ti/Al/B powders. This system was selected because of the large exothermic heat of reaction in the Ti+2B reaction, which can support the subsequent Al-combustion reaction. The unique deformation state achievable by such high-pressure loading methods can drive chemical reactions, mediated by microstructure-dependent meso-scale phenomena. Design of the next generation of multifunctional energetic structural materials (MESMs) consisting of metal-metal mixtures requires an understanding of the mechanochemical processes leading to chemical reactions under dynamic loading to properly engineer the materials. The highly heterogeneous and hierarchical microstructures inherent in compacted powder mixtures further complicate understanding of the mechanochemical origins of shock-induced reaction events due to the disparate length and time scales involved. A two-pronged approach is taken where impact experiments in both the uniaxial stress (rod-on-anvil Taylor impact experiments) and uniaxial strain (instrumented parallel-plate gas-gun experiments) load configurations are performed in conjunction with highly-resolved microstructure-based simulations replicating the experimental setup. The simulations capture the bulk response of the powder to the loading, and provide a look at the meso-scale deformation features observed under conditions of uniaxial stress or strain. Experiments under uniaxial stress loading reveal an optimal stoichiometry for Ti+2B mixtures containing up to 50% Al by volume, based on a reduced impact velocity threshold required for impact-induced reaction initiation as evidenced by observation of light emission. Uniaxial strain experiments on the Ti+2B binary mixture show possible expanded states in the powder at pressures greater than 6 GPa, consistent with the Ballotechnic hypothesis for shock-induced chemical reactions. Rise-time dispersive signatures are consistently observed under uniaxial strain loading, indicating complex compaction phenomena, which are reproducible by the meso-scale simulations. The simulations show the prevalence of shear banding and particle agglomeration in the uniaxial stress case, providing a possible rationale for the lower observed reaction threshold. Bulk shock response is captured by the uniaxial strain meso-scale simulations and is compared with PVDF stress gauge and VISAR traces to validate the simulation scheme. The simulations also reveal the meso-mechanical origins of the wave dispersion experimentally recorded by PVDF stress gauges.