Software forking---creating a variant product by copying and modifying an existing project---is often considered an ad hoc, low cost alternative to principled product line development. To maintain forked projects, developers need to manually port existing features or bug-fixes from one project to another. Such manual porting is not only tedious but also error-prone. When the contexts of the ported code vary, developers often have to adapt the ported code to fit its surroundings. Faulty adaptations or inconsistent updates of the ported code could potentially introduce subtle inconsistencies in the codebase. To build a deeper understanding to cross-system porting and porting related errors, this dissertation investigates: (1) How can we identify ported code from software version histories? (2) What is the overhead of cross-system porting required to maintain forked projects? (3) What is the extent and characteristics of porting errors that occur in practice? and (4) How can we detect and characterize potential porting errors? As a first step towards assessing the overhead of cross-system porting, we implement REPERTOIRE, a tool to analyze repeated work of cross-system porting across peer projects. REPERTOIRE can detect ported edits between program patches with high accuracy of 94% precision and 84% recall. Using REPERTOIRE, we study the temporal, spatial, and developer dimensions of cross-system porting using 18 years of parallel evolution history of the BSD product family. Our study finds that cross-system porting happens periodically and the porting rate does not necessarily decrease over time. The upkeep work of porting changes from peer projects is significant and currently, porting practice seems to heavily depend on developers doing their porting job on time. Analyzing version histories of Linux and FreeBSD, we derive five categories of porting errors, including incorrect control- and data-flow, code redundancy, and inconsistent identifier and token renamings. Leveraging this categorization, we design a static control- and data-dependence analysis technique, SPA, to detect and characterize porting inconsistencies. SPA detects porting inconsistencies with 65% to 73% precision and 90% recall, and identify inconsistency types with 58% to 63% precision and 92% recall on average. In a comparison with two existing error detection tools, SPA outperforms them with 14% to 17% better precision. / text

The composite material of different density, where porous cement paste serves as matrix and crushed waste expanded polystyrene packages serve as inclusions, was developed. The compositions of formative mixtures and technological parameters of production for this composite material were selected and its properties were investigated. / Sukurta skirtingo tankio kompozitinė medžiaga, kurioje matrica yra poringoji cemento tešla, o intarpai - trupintos polistireninio putplasčio pakavimo taros atliekos. Parinktos minėtos kompozitinės medžiagos formavimo mišinių sudėtys, gamybos technologiniai parametrai ir ištirtos jos bandinių savybės.

Applications of chromium vary widely (refractories, chemicals and metallurgical); however, the greatest benefit of chromium is its ability to improve the corrosion resistance, strength and hardness of steel. South Africa possesses approximately 75% of the viable global chromite reserves and, as a result, dominates the ferrochrome market with production in excess of 5 million mega tonnes per year - making it an industry of extreme importance to the South African economy Submerged arc ferroalloy production furnaces mainly use Soderberg electrodes - self–baking continuous electrodes that are produced in situ during furnace operation. Electrode breakings may affect a furnace in a number of ways depending on the nature and location of the break. Low furnace power input, abnormal charging and tapping conditions, as well as loss of production are among the more common negative implications associated with electrode breaks. The successful operation of Soderberg electrodes is dependent on two main factors: high quality electrode paste and effective electrode management procedures. This study focused on electrode paste quality. The raw materials utilised in the production of Soderberg electrode paste consists of calcined anthracite mixed with a tar pitch binder. In this study the focus was on the development of an experimental procedure to measure the dimensional changes of electrode paste raw materials as a function of temperature by means of thermomechanical analysis (TMA). Three uncalcined anthracite (Zululand chips, Zululand duff, and Tendele duff) and two tar pitch samples (low and high softening point pitches, i.e. LSP and HSP) were obtained from a local paste producer. Electrode graphite samples were also obtained from a local pre–baked electrode supplier. The experimental procedure for both the anthracite and tar pitches consisted of two phases: sample preparation and TMA measurements. During the sample preparation procedure for the tar pitches, the two tar pitches were heat treated in order to prevent softening in the TMA (preventing possibly damage the instrument), where after pellets were pressed for TMA measurement. The anthracite samples were calcined at 1200, 1300 and 1400°C in the anthracite sample preparation phase. TMA sample pellets of calcined and uncalcined anthracite were pressed using only water as a binder. TMA was performed on pellets produced from the heat–treated tar pitch samples, uncalcined and calcined anthracite samples, as well as core drilled pellets of the pre–baked electrode graphite. The dimensional changes of these pellets were measured, as a function of temperature, through three consecutive heating (room temperature to 1300°C) and cooling (1300°C to approximately 100°C) cycles under a N2 atmosphere. A significant shrinkage (> 12%) for both the LSP and HSP tar pitches occurred during the first TMA heating cycle. During the second and third heating cycles of the LSP and HSP tar pitches, dimensional changes were approximately 2%. This indicates that substantial structural reordering of the carbonaceous binder takes place during the first heating cycle. TMA results obtained for all three the calcined anthracite samples investigated indicated thermal dimensional changes of less than 1%. The anthracite samples calcined at the highest experimental calcination temperature (1400°C) prior to TMA analysis had the smallest dimensional changes. This confirmed that higher calcination temperatures result in a higher level of structural ordering and dimensional stability. Considering the combined calcined anthracite and tar pitches TMA results, the importance of the initial baking of a Soderberg electrode at temperatures exceeding the baking isotherm temperature (475°C) becomes apparent - the dimensional behaviour of the tar pitch binder and the calcined anthracite differ dramatically, making the newly–formed electrode very susceptible to breakage. Once structural reordering of the pitch had taken place, thermal dimensional behaviours of the materials are much more similar, significantly reducing the risk of thermal shock–induced electrode breakages. In contrast to the relatively small dimensional changes measured for the calcined anthracite samples, the shrinkages measured for the uncalcined samples during the first TMA heating/cooling cycle were substantial (6–8%). This indicates the importance of the anthracite calcination process, before the electrode paste is formulated. Improperly calcined anthracite present in electrode paste would result in additional dimensional shrinkage that would have to be accommodated in the baking of a new electrode section. Considering the large shrinkage of the tar pitch that already takes place, it is unlikely that a strong enough electrode would be formed if this occurs. From the results, it also became apparent that the anthracite with the highest fixed carbon and lowest ash contents exhibited the smallest shrinkage during in situ TMA calcination. High fixed carbon, low ash type anthracites are therefore less prone to dimensional instabilities in Soderberg electrodes, as a result of poor calcination. The dimensional changes observed in the calcined anthracites were very similar to those observed for the electrode graphite samples. The expansions/shrinkages observed in the graphite samples were mostly less than 0.5%, whereas the expansions/shrinkages observed in the various calcined anthracites were approximately 0.6 to 0.9%. The difference in the magnitude of the dimensional behaviour between the calcined anthracites and the graphite can be attributed to the fact that the graphite had already undergone maximum structural ordering (having been pre–baked at 3000°C). / Thesis (M.Ing. (Chemical Engineering))--North-West University, Potchefstroom Campus, 2012.

Applications of chromium vary widely (refractories, chemicals and metallurgical); however, the greatest benefit of chromium is its ability to improve the corrosion resistance, strength and hardness of steel. South Africa possesses approximately 75% of the viable global chromite reserves and, as a result, dominates the ferrochrome market with production in excess of 5 million mega tonnes per year - making it an industry of extreme importance to the South African economy Submerged arc ferroalloy production furnaces mainly use Soderberg electrodes - self–baking continuous electrodes that are produced in situ during furnace operation. Electrode breakings may affect a furnace in a number of ways depending on the nature and location of the break. Low furnace power input, abnormal charging and tapping conditions, as well as loss of production are among the more common negative implications associated with electrode breaks. The successful operation of Soderberg electrodes is dependent on two main factors: high quality electrode paste and effective electrode management procedures. This study focused on electrode paste quality. The raw materials utilised in the production of Soderberg electrode paste consists of calcined anthracite mixed with a tar pitch binder. In this study the focus was on the development of an experimental procedure to measure the dimensional changes of electrode paste raw materials as a function of temperature by means of thermomechanical analysis (TMA). Three uncalcined anthracite (Zululand chips, Zululand duff, and Tendele duff) and two tar pitch samples (low and high softening point pitches, i.e. LSP and HSP) were obtained from a local paste producer. Electrode graphite samples were also obtained from a local pre–baked electrode supplier. The experimental procedure for both the anthracite and tar pitches consisted of two phases: sample preparation and TMA measurements. During the sample preparation procedure for the tar pitches, the two tar pitches were heat treated in order to prevent softening in the TMA (preventing possibly damage the instrument), where after pellets were pressed for TMA measurement. The anthracite samples were calcined at 1200, 1300 and 1400°C in the anthracite sample preparation phase. TMA sample pellets of calcined and uncalcined anthracite were pressed using only water as a binder. TMA was performed on pellets produced from the heat–treated tar pitch samples, uncalcined and calcined anthracite samples, as well as core drilled pellets of the pre–baked electrode graphite. The dimensional changes of these pellets were measured, as a function of temperature, through three consecutive heating (room temperature to 1300°C) and cooling (1300°C to approximately 100°C) cycles under a N2 atmosphere. A significant shrinkage (> 12%) for both the LSP and HSP tar pitches occurred during the first TMA heating cycle. During the second and third heating cycles of the LSP and HSP tar pitches, dimensional changes were approximately 2%. This indicates that substantial structural reordering of the carbonaceous binder takes place during the first heating cycle. TMA results obtained for all three the calcined anthracite samples investigated indicated thermal dimensional changes of less than 1%. The anthracite samples calcined at the highest experimental calcination temperature (1400°C) prior to TMA analysis had the smallest dimensional changes. This confirmed that higher calcination temperatures result in a higher level of structural ordering and dimensional stability. Considering the combined calcined anthracite and tar pitches TMA results, the importance of the initial baking of a Soderberg electrode at temperatures exceeding the baking isotherm temperature (475°C) becomes apparent - the dimensional behaviour of the tar pitch binder and the calcined anthracite differ dramatically, making the newly–formed electrode very susceptible to breakage. Once structural reordering of the pitch had taken place, thermal dimensional behaviours of the materials are much more similar, significantly reducing the risk of thermal shock–induced electrode breakages. In contrast to the relatively small dimensional changes measured for the calcined anthracite samples, the shrinkages measured for the uncalcined samples during the first TMA heating/cooling cycle were substantial (6–8%). This indicates the importance of the anthracite calcination process, before the electrode paste is formulated. Improperly calcined anthracite present in electrode paste would result in additional dimensional shrinkage that would have to be accommodated in the baking of a new electrode section. Considering the large shrinkage of the tar pitch that already takes place, it is unlikely that a strong enough electrode would be formed if this occurs. From the results, it also became apparent that the anthracite with the highest fixed carbon and lowest ash contents exhibited the smallest shrinkage during in situ TMA calcination. High fixed carbon, low ash type anthracites are therefore less prone to dimensional instabilities in Soderberg electrodes, as a result of poor calcination. The dimensional changes observed in the calcined anthracites were very similar to those observed for the electrode graphite samples. The expansions/shrinkages observed in the graphite samples were mostly less than 0.5%, whereas the expansions/shrinkages observed in the various calcined anthracites were approximately 0.6 to 0.9%. The difference in the magnitude of the dimensional behaviour between the calcined anthracites and the graphite can be attributed to the fact that the graphite had already undergone maximum structural ordering (having been pre–baked at 3000°C). / Thesis (M.Ing. (Chemical Engineering))--North-West University, Potchefstroom Campus, 2012.

Orientador: Devaney Ribeiro do Carmo / Resumo: O presente trabalho descreve a preparação de partículas formadas a partir de Pentacianonitrosilferrato (III) de sódio e Cloreto de cádmio. As partículas foram preparadas em quatro proporções empregando os solventes Água/Formamida (100:0; 80:20; 40:60; 0:100) com o objetivo de investigar a sua influência na morfologia, topologia e nas propriedades eletrocatalíticas das partículas. Os materiais foram caracterizados por técnicas espectroscópicas e eletroquímica tais como: Espectroscopia na região do infravermelho (FTIR), Espectroscopia Raman, Reflectância difusa (UV-visível), Difração de raios-X (DRX), Microscopia eletrônica de varredura (MEV), Espectrometria de energia dispersiva de raios-X (EDS), Microscopia eletrônica de transmissão (MET) e voltametria cíclica (VC). Após as caracterizações foram realizados estudos sobre as propriedades eletroquímicas dos materiais utilizando um eletrodo de pasta de grafite. Dos quatro sistemas estudados, apenas dois foram sensíveis à concentrações de isoniazida, a saber o CdNP-3 e CdNP-4. Ambos os sistemas apresentaram duas regiões lineares de sinal em função da concentração com limites de detecção de 6,80×10-5 mol L-1 e 7,07×10-4 mol L-1, e 2,18×10-4 mol L-1 e 1,16×10-3 mol L-1 para os sistemas CdNP-3 e CdNP-4, respectivamente. Para o sistema CdNP-3 observou-se uma sensibilidade amperométrica de 23,96 mA mol L-1 e 10, 83 mA mol L-1, já para CdNP-4 observou-se uma sensibilidade amperométrica de 17,80 mA mol L-1 e 5,79 mA mol L-1 para cada reg... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The present work describes the preparation of particles formed from Sodium Pentacyanonitrosylferrate (III) and Cadmium Chloride. The particles were prepared in four ratios using solvents Water / Formamide (100:0, 80:20, 40:60, 0:100) to investigate the influence on particle morphology, topology and electrocatalytic properties. The materials were characterized by spectroscopic and electrochemical techniques such as: Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, Diffuse reflectance (UV-Visible), X-ray diffraction (XRD), Scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDS), Transmission electron microscopy (TEM) and Cyclic voltammetry (CV). After the characterization studies, the electrochemical properties of materials were performed using a graphite paste electrode. Of the four systems studied, only two tests with concentrations of isoniazid, CdNP-3 and CdNP-4. Both systems presented two linear concentrations with detection limits of 6.80 × 10-5 mol L-1 and 7.07 × 10-4 mol L-1 and 2.18 × 10-4 mol L-1 and 1.16 × 10-3 mol L-1 for the CdNP-3 and CdNP-4 systems, respectively. For the CdNP-3 system, an amperometric sensitivity of 23.96 mA mol L-1 and 10.83 mA mol L-1 was observed, whereas for CdNP-4 an amperometric sensitivity of 17.80 mA mol L-1 and 5.79 mA mol L-1 for each linear region. / Mestre

Resumo: Objetivou-se avaliar o crescimento, a produção e composição físicoquímica de raízes e amidos de mandioquinha-salsa e suas potencialidades. Foram avaliados nove clones BGH (4560, 5741, 5744, 5746, 5747, 6414, 6513, 6525 e 7609) e a cultivar Amarela de Senador Amaral, os quais foram cultivados na Fazenda Experimental São Manuel- SP, safra de 2009. O delineamento experimental utilizado no plantio foi de blocos casualizados com três repetições. Foram avaliados o crescimento vegetativo durante o cultivo, produção total, comercial, por classe e calibre das raízes e as características físico-químicas das raízes: umidade, amido, cinzas, proteína bruta, matéria-graxa, açúcares, fibra bruta, pH, acidez e cor e caracterização do amido quanto ao teor de amilose, propriedades térmicas e de pasta. Os materiais que destacaram foram BGH 6414, maior crescimento vegetativo; 'Amarela de Senador Amaral' e BGH 5741, menores quantidades de raízes por planta; e BGH 6414, menor produção total, comercial, nas classes e calibres. Na caracterização da coloração das raízes, BGH 6513 e BGH 4560 apresentaram menores valores de luminosidade, BGH 6414 e BGH 5744 maiores valores para croma a* e BGH 5746, BGH 6513 e BGH 5744 os menores valores para o croma b*. A cultivar Amarela de Senador Amaral apresentou pH mais alto e a maior quantidade de acidez foi observada no clone BGH 6525. Os clones que apresentaram maiores teores de umidade foram BGH 7609 e BGH 6414. Os clones BGH 5744, BGH 7609, BGH 6414 e BGH 5741 apresentaram menores teores de cinzas e na avaliação de matéria graxa BGH 6525, BGH 5741 e BGH 5744 apresentaram os maiores teores. O clone BGH 7609 apresentou maior teor de fibras, açúcares totais, menor teor de amido, maiores temperaturas de gelatinização e menor temperatura de pico nos amidos retrogradados, além de apresentar a maior porcentagem de amidos retrogradados... (resumo completo, clicar acesso eletrônico abaixo) / Abstract: The objective was to evaluate the growth, yield and physico-chemical composition of starches from roots and peruvian carrot and its capabilities. We evaluated nine clones BGH (4560, 5741, 5744, 5746, 5747, 6414, 6513, 6525 and 7609) and cultivar Amarela de Senador Amaral, which were cultivated at the Experimental Farm São Manuel-SP, the 2009 harvest. The experiment was planted in a randomized block design with three replications. We evaluated the vegetative growth during cultivation, total production, trade, by class and size of roots and the physicochemical characteristics of the roots for moisture, starch, ash, protein, raw grease, sugar, crude fiber, pH, acidity and color and characterization of starch and amylose content, thermal properties and paste. The materials that were highlighted BGH 6414, increased vegetative growth, 'Amarela de Senador Amaral' and BGH 5741, lower amounts of roots per plant, and BGH 6414, lower overall production, commercial classes and sizes. In characterizing the coloration of the roots, BGH 6513 and BGH 4560 had lower levels of brightness, BGH 6414 and BGH 5744 higher values for chroma and a* BGH 5746, BGH 6513 and BGH 5744 the lowest values in the chrome b*. The cultivar Amarela de Senador Amaral presented higher pH and higher amount of acidity was observed in clones BGH 6525. The clones that showed higher levels of humidity were BGH 7609 and BGH 6414. Clones BGH 5744, BGH 7609, BGH 6414 and BGH 5741 had lower levels of ash and fatty matter in the evaluation of BGH 6525, BGH 5741 and BGH 5744 showed the highest levels. BGH Clone 7609 showed a higher fiber content, total sugar, less starch, higher temperatures and lower gelatinization peak temperature in starch downgraded, besides presenting the highest percentage of retrograded starch. Differ significantly higher than BGH 4560 and 'Amarela de Senador Amaral "in crude protein and BGH 5746, BGH 6513... (Complete abstract click electronic access below) / Orientador: Magali Leonel / Coorientador: Silvio José Bicudo / Banca: Cláudio Cabello / Banca: Marcelo Alvares de Oliveira / Mestre

Concrete, the major construction material used in the civil industry worldwide, displays remarkable performance and economic benefits. Yet, it also presents a huge environmental impact producing about 7% of the global carbon dioxide (CO2). Given the rise of global warming concerns, studies have been focusing on alternatives to reduce the amount of Portland cement (PC), which is the least sustainable ingredient of the mixture, for example by adopting particle packing model (PPM) techniques. Although a promising alternative, there is currently a lack of studies regarding the efficiently use of PPMs to reduce PC without compromising the fresh and hardened properties of the material. This work appraises the influence of PPMs and advanced mix-design techniques on the fresh (rheological behaviour) and hardened (compressive strength, modulus of elasticity, porosity, and permeability) state behaviours of systems with reduced amount of PC, the so-called low cement content (LCC) concrete. Results show that is possible to produce eco-efficient concrete maintaining and/or enhancing fresh and hardened properties of the material. Nevertheless, further durability and long-term behaviour must be performed on LCC systems.

The Self-Compacting Concrete (SCC) it needs of the high amount of fine in yo ur composition to assist your properties in the fresh state. In the context of the fine materials if show the Residue of the Improvement of the Marble and Granite (RBMG), which was chosen to compose the dosagem of CAA in that research. This was a form of contributing with the technological progress and maintainable development of the concrete. Using Gomes' Methodology (2002) for obtaining of SCC, the study of the paste was developed through the rehearsals in the Cone of Marsh and in the Mini-slump and the study of the mortar using the rehearsals in the Cone of Marsh and in the cone log of the consistence table, all, in the sense of obtaining the percentile great of superplasticizer and an appropriate amount of RBMG in the composition of the mixture. Starting from parameters obtained in the study of the paste and mortar was given segment to a practical application of completion of premolded pieces, without the use of any type of mechanical vibration, with self-compacting mortar. Soon after, through the study of the composition of the granular skeleton it was obtained the great relationship among the small and great aggregate. The study of the concrete was developed using the rehearsals of Slump-flow, V Funnel, L Box and U Pipe, for the tests of your properties in the fresh state, such as: filling ability, passing ability and segregation resistance. In this study they were obtained two Self Compacting Concrete, a just using RBMG and other with 3% of sílica fume; in this it was verified some improvements in the viscosity and in the cohesion of the mixture. For both concretes they were moulded cylindrical specimens of 10cm x 20cm and 15cm x 30cm for study of the resistance to the compression to the 7 days and the 28 days; module of static deformation and resistance to the traction in the diametrical compression to the 28 days. The results of the accomplished rehearsals indicated for the technical viability of the use of RBMG in the production of SCC. / O Concreto Auto-Adensável (CAA) necessita de uma alta quantidade de finos em sua composição para atender suas propriedades no estado fresco. No contexto dos materiais finos se apresenta o Resíduo do Beneficiamento do Mármore e Granito (RBMG), o qual foi escolhido para compor a dosagem do CAA nessa pesquisa. Esta foi uma forma de contribuir com o avanço tecnológico e desenvolvimento sustentável do concreto. Utilizando a Metodologia de Gomes (2002) para obtenção do CAA, foi desenvolvido o estudo da pasta através dos ensaios no Cone de Marsh e no Mini-slump e o estudo da argamassa usando os ensaios no Cone de Marsh e no Tronco de cone da mesa de consistência, todos, no sentido de se obter o percentual ótimo de superplastificante e uma quantidade adequada do RBMG na composição da mistura. A partir de parâmetros obtidos no estudo da pasta e argamassa foi dado segmento a uma aplicação prática de preenchimento de peças pré-moldadas, sem a utilização de nenhum tipo de vibração mecânica, com argamassa auto-adensável. Em seguida, através do estudo da composição do esqueleto granular foi obtida a relação ótima entre o agregado miúdo e graúdo. O estudo do concreto foi desenvolvido utilizando os ensaios de Espalhamento, Funil V, Caixa L e Tubo em U, para os testes de suas propriedades no estado fresco, tais como: capacidade de preenchimento, capacidade de passagem por obstáculos e resistência à segregação. Neste estudo foram obtidos dois Concretos Auto- Adensáveis, um usando apenas o RBMG e outro com 3% de sílica ativa; neste foi verificado algumas melhoras na viscosidade e na coesão da mistura. Para ambos concretos foram moldados corpos-de-prova cilíndricos de 10cm x 20cm e 15cm x 30cm para estudo da resistência à compressão aos 7 dias e aos 28 dias; módulo de deformação estática e resistência à tração na compressão diametral aos 28 dias. Os resultados dos ensaios realizados indicaram pela viabilidade técnica da utilização do RBMG na produção de CAA.

Les centrales nucléaires jouent un rôle important au niveau mondial dans la production d'électricité aujourd'hui. Dans l'histoire humaine, deux accidents tragiques ont déjà eu lieu, à Tchernobyl et Fukushima, provoquant des fuites des matières radioactives. Pour éviter ce genre d'accident dans la future, la construction en béton prend un rôle important en tant que matériau de construction de confinement qui est la dernière barrière pour isoler la matière radioactive de l'environnement. La compréhension des transferts dans le béton dans des circonstances graves, en particulier à étudier le comportement du béton sous haute température jusqu'à 200°C. Dans la première partie, un modèle de déshydratation a été appliqué dans le modèle thermo-hygro. Le modèle thermo-hygro a ensuite été mis en oeuvre pour simuler une maquette dont les résultats expérimentaux sont disponibles dans la littérature, sans tenir compte des comportements mécaniques. Enfin, des études paramétrique ont été réalisées pour étudier l'influence de certains paramètres. Le modèle à ensuite été appliqué à des structures sous vitesse de chauffage différente, et le modèle à ensuite été appliqué à des structure sous rythme de chauffage différents et celles avec des épaisseurs différentes pour comparer les profiles de température et de pression de gaz à travers de la mur. / Nuclear power plant now takes an important part in the world's electricity generation. In human history, there have already been two tragic accidents in Chernobyl and Fukushima causing severe radioactive matter leakage. To pre- vent this kind of accident from happening again, concrete structure plays an important role as material of containment building, which is the last barrier to isolate the radioactive matter from the environment. Hence, the transfer properties of concrete under severe circumstances, especially high tempera- ture, are important for this usage. This PhD thesis aims to investigate the behavior of the concrete under high temperature up to 200°C. In the first part, a dehydration model was proposed. The model consists of different dehydration sub-models for main hydrates in the cement paste. In the second part, the dehydration model was implemented in a thermo-hygral model. The thermo- hygral model was then used to simulate a mock-up for which experimental results are available in the literature, without considering the mechanical behaviors. At last, parametric studies were performed to investigate the influ- ence of some parameters, and the model was then applied to structures under different heating rates, and structures with different thicknesses to compare the temperature and gas pressure profiles across a wall.

L’assemblage et le conditionnement en électronique représentent un enjeu de création de nouveaux systèmes électroniques hybrides rassemblant sur un même substrat des éléments électroniques, optiques, mécaniques… La technologie Flip-chip , introduite par IBM et baptisée C4 (Control Collapse Chip Connection), garantit une plus grande densité d’intégration tout en gardant les mêmes dimensions de puce. Au coeur de cette technologie, le « Bumping » est un procédé qui consiste en l’introduction d’une microbille conductrice entre deux plots de connexion des puces afin de réaliser une liaison électrique et mécanique avec le niveau de packaging suivant. La technique de dépôt par sérigraphie de pâte à braser est récemment devenue pratique en raison de son adaptation aux alliages sans plomb. Cette méthode présente l'avantage d'un faible coût et d'une possible production à grande échelle. Nous avons donc choisi de développer cette technique afin d’obtenir des matrices de connexions électriques de dimensions comprises entre 50 μm et 100 μm, pour une pâte à braser de type Sn3.0Ag0.5Cu. Nous avons déterminé les paramètres de sérigraphie afin d’obtenir un minimum d’étalement de pâte pour un remplissage maximum des ouvertures du masque choisi en Ni-électroformé d’épaisseur 50μm : une vitesse de racle de 20mm/s et une vitesse de démoulage de 4mm/s sont par exemple à retenir pour une pâte de type 5. L’étude du masque de sérigraphie a conduit au choix d’ouvertures circulaires. Des formes de billes circulaires ont été obtenues pour des UBM (Under Bump Metallurgy) également circulaires, de diamètre ¼ et ½ le diamètre de l’ouverture du masque. L’optimisation du profil de refusion a permis de déterminer qu’un palier à 180°C, un TAL de 90s ou plus et une température maximale à 250°C favorisaient l’obtention de billes circulaires avec absence de vides. Pour une pâte de type 6, des billes de 60à 70μm de diamètre ont été obtenues pour des ouvertures de masque de 100μm. Une étude de fiabilité de ces billes à partir de tests de cisaillement et de l’analyse des IMC (composés intermétalliques) formés après refusion a permis de montrer que des UBM en Cr-Cu-Au, de diamètre égal à la moitié de l’ouverture du masque, permettaient d’assurer un meilleur maintien mécanique des billes / The semiconductor industry has continuously improved its products by increasing the density of integration resulting in an increasing of the I/Os, always with a low cost requirement. To obtain high-density and high-speed packaging, the Flip-Chip interconnection technology was introduced by IBM also called C4 (Control Collapse Chip Connection). Solder bumps have been widely used in electronic industry and were generally based on the Sn-Pb alloy, for its low melting point and good wetting property. Containing highly toxic element (Pb), Pb-Sn solder alloy has been banned. The ternary alloy Sn-Ag-Cu seems to be the best compromise, in fact it as physical and chemical characteristics equivalent to that of Sn-Pb.In this study we are interested to optimize stencil printing process and adjust it with the flip-chip technology, in order to obtain solder bumps which height is between 50µm and 100µm associated to pitches less than or equal to 200µm, using Sn-3.0Ag-0.5Cu solder paste. We have optimized the stencil printing parameters machine, the stencil apertures shape and size (circular shape and 50µm height, for a Ni-electroformed stencil). Spherical solder balls have been achieved with circular UBM (Under Bump Metallurgy), which diameter is ¼ and ½ the diameter of the stencil aperture. The reflow thermal profile is the key to the formation of a reliable solder bump. It must allow a homogeneous reflow for all particles of the metallic solder paste. We define a thermal profile with a Time above liquidus (TAL) of 90s, a temperature in soaking zone (Ts) of 180°C and a maximum temperature (Tmax) of 250°C. For type 6 solder pastes, balls of 60-70µm diameter have been obtained for 100µm stencil apertures.The quality of a solder joint is directly related to the adhesion of the solder ball to the substrate. Among the various methods of mechanical testing, shear testing is the most widely used to assess the strength of the attachment of beads to the substrate and determine the fragility of the ball at the interface caused by the intermetallic layer compounds (IMC) formed after the reflow step. We have shown that Cr-Cu-Au UBM, with a diameter equal to the half of the stencil aperture, ensure the mechanical adhesion of the balls