Tunable visible photoluminescence of powdered silica glass

intense photoluminescence in the visible region was observed at room temperature in standard soda-lime-silica glass powder, mechanically milled in a high-energy attrition mill. The emission band maximum shows an interesting dependence on the exciting wavelength, suggesting the possibility to tune the PL emission. These findings indicate that the photoluminescence may be directly related to unsatisfied chemical bonds correlated with the high surface area. The Raman scattering and ultraviolet-visible optical reflectance measurements corroborate this assertion. Transmission electron microscopy measurements indicate that samples milled more than 10 h present the formation of nanocrystallites with about 10-20 nm. (C) 2007 Elsevier B.V. All rights reserved.

Uma linguagem de modelagem da interação para auxiliar a comunicação designer-usuário

The development of interactive systems involves several professionals and the integration between them normally uses common artifacts, such as models, that drive the development process. In the model-driven development approach, the interaction model is an artifact that includes the most of the aspects related to what and how the user can do while he/she interacting with the system. Furthermore, the interactive model may be used to identify usability problems at design time. Therefore, the central problematic addressed by this thesis is twofold. In the first place, the interaction modeling, in a perspective that helps the designer to explicit to developer, who will implement the interface, the aspcts related to the interaction process. In the second place, the anticipated identification of usability problems, that aims to reduce the application final costs. To achieve these goals, this work presents (i) the ALaDIM language, that aims to help the designer on the conception, representation and validation of his interactive message models; (ii) the ALaDIM editor, which was built using the EMF (Eclipse Modeling Framework) and its standardized technologies by OMG (Object Management Group); and (iii) the ALaDIM inspection method, which allows the anticipated identification of usability problems using ALaDIM models. ALaDIM language and editor were respectively specified and implemented using the OMG standards and they can be used in MDA (Model Driven Architecture) activities. Beyond that, we evaluated both ALaDIM language and editor using a CDN (Cognitive Dimensions of Notations) analysis. Finally, this work reports an experiment that validated the ALaDIM inspection method

Um ambiente multi-middleware para desenvolvimento de aplicações distribuídas

This work presents a proposal of a multi-middleware environment to develop distributed applications, which abstracts different underlying middleware platforms. This work describes: (i) the reference architecture designed for the environment, (ii) an implementation which aims to validate the specified architecture integrating CORBA and EJB, (iii) a case study illustrating the use of the environment, (iv) a performance analysis. The proposed environment allows interoperability on middleware platforms, allowing the reuse of components of different kinds of middleware platforms in a transparency away to the developer and without major losses in performance. Also in the implementation we developed an Eclipse plugin which allows developers gain greater productivity at developing distributed applications using the proposed environment

MARISA-MDD: uma abordagem para transformações entre modelos orientados a aspectos: dos requisitos ao projeto detalhado

Aspect Oriented approaches associated to different activities of the software development process are, in general, independent and their models and artifacts are not aligned and inserted in a coherent process. In the model driven development, the various models and the correspondence between them are rigorously specified. With the integration of aspect oriented software development (DSOA) and model driven development (MDD) it is possible to automatically propagate models from one activity to another, avoiding the loss of information and important decisions established in each activity. This work presents MARISA-MDD, a strategy based on models that integrate aspect-oriented requirements, architecture and detailed design, using the languages AOV-graph, AspectualACME and aSideML, respectively. MARISA-MDD defines, for each activity, representative models (and corresponding metamodels) and a number of transformations between the models of each language. These transformations have been specified and implemented in ATL (Atlas Definition Language), in the Eclipse environment. MARISA-MDD allows the automatic propagation between AOV-graph, AspectualACME, and aSideML models. To validate the proposed approach two case studies, the Health Watcher and the Mobile Media have been used in the MARISA-MDD environment for the automatic generation of AspectualACME and aSideML models, from the AOV-graph model

The Temperature and Humidity in a Low-Flow Anesthesia Workstation With and Without a Heat and Moisture Exchanger

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Uma abordagem dirigida por modelos para gerência de variabilidade e execução de processos de software

This dissertation presents a model-driven and integrated approach to variability management, customization and execution of software processes. Our approach is founded on the principles and techniques of software product lines and model-driven engineering. Model-driven engineering provides support to the specification of software processes and their transformation to workflow specifications. Software product lines techniques allows the automatic variability management of process elements and fragments. Additionally, in our approach, workflow technologies enable the process execution in workflow engines. In order to evaluate the approach feasibility, we have implemented it using existing model-driven engineering technologies. The software processes are specified using Eclipse Process Framework (EPF). The automatic variability management of software processes has been implemented as an extension of an existing product derivation tool. Finally, ATL and Acceleo transformation languages are adopted to transform EPF process to jPDL workflow language specifications in order to enable the deployment and execution of software processes in the JBoss BPM workflow engine. The approach is evaluated through the modeling and modularization of the project management discipline of the Open Unified Process (OpenUP)

Um modelo conceitual baseado em MDD e padrões para evolução de sistemas OA

Aspect-Oriented Software Development (AOSD) is a technique that complements the Object- Oriented Software Development (OOSD) modularizing several concepts that OOSD approaches do not modularize appropriately. However, the current state-of-the art on AOSD suffers with software evolution, mainly because aspect definition can stop to work correctly when base elements evolve. A promising approach to deal with that problem is the definition of model-based pointcuts, where pointcuts are defined based on a conceptual model. That strategy makes pointcut less prone to software evolution than model-base elements. Based on that strategy, this work defines a conceptual model at high abstraction level where we can specify software patterns and architectures that through Model Driven Development techniques they can be instantiated and composed in architecture description language that allows aspect modeling at architecture level. Our MDD approach allows propagate concepts in architecture level to another abstraction levels (design level, for example) through MDA transformation rules. Also, this work shows a plug-in implemented to Eclipse platform called AOADLwithCM. That plug-in was created to support our development process. The AOADLwithCM plug-in was used to describe a case study based on MobileMedia System. MobileMedia case study shows step-by-step how the Conceptual Model approach could minimize Pointcut Fragile Problems, due to software evolution. MobileMedia case study was used as input to analyses evolutions on software according to software metrics proposed by KHATCHADOURIAN, GREENWOOD and RASHID. Also, we analyze how evolution in base model could affect maintenance on aspectual model with and without Conceptual Model approaches

Dos requisitos à arquitetura em linhas de produtos de software: uma estratégia de transformações entre modelos

The tracking between models of the requirements and architecture activities is a strategy that aims to prevent loss of information, reducing the gap between these two initial activities of the software life cycle. In the context of Software Product Lines (SPL), it is important to have this support, which allows the correspondence between this two activities, with management of variability. In order to address this issue, this paper presents a process of bidirectional mapping, defining transformation rules between elements of a goaloriented requirements model (described in PL-AOVgraph) and elements of an architectural description (defined in PL-AspectualACME). These mapping rules are evaluated using a case study: the GingaForAll LPS. To automate this transformation, we developed the MaRiPLA tool (Mapping Requirements to Product Line Architecture), through MDD techniques (Modeldriven Development), including Atlas Transformation Language (ATL) with specification of Ecore metamodels jointly with Xtext , a DSL definition framework, and Acceleo, a code generation tool, in Eclipse environment. Finally, the generated models are evaluated based on quality attributes such as variability, derivability, reusability, correctness, traceability, completeness, evolvability and maintainability, extracted from the CAFÉ Quality Model

Apoiando a Construcao de Testes de Aceitacao Automatizados a partir da Especificacao de Requisitos

A automação consiste em uma importante atividade do processo de teste e é capaz de reduzir significativamente o tempo e custo do desenvolvimento. Algumas ferramentas tem sido propostas para automatizar a realização de testes de aceitação em aplicações Web. Contudo, grande parte delas apresenta limitações importantes tais como necessidade de valoração manual dos casos de testes, refatoração do código gerado e forte dependência com a estrutura das páginas HTML. Neste trabalho, apresentamos uma linguagem de especificação de teste e uma ferramenta concebidas para minimizar os impactos propiciados por essas limitações. A linguagem proposta dá suporte aos critérios de classes de equivalência e a ferramenta, desenvolvida sob a forma de um plug-in para a plataforma Eclipse, permite a geração de casos de teste através de diferentes estratégias de combinação. Para realizar a avaliação da abordagem, utilizamos um dos módulos do Sistema Unificado de Administração Publica (SUAP) do Instituto Federal do Rio Grande do Norte (IFRN). Participaram da avaliação analistas de sistemas e um técnico de informática que atuam como desenvolvedores do sistema utilizado.

Effect of thermocycling on the flexural and impact strength of urethane-based and high-impact denture base resins

Objective: Mechanical properties of the acrylic resins used for denture fabrication may be influenced by water and temperature. Thus, the aim of this study was to evaluate the effect of thermocycling on the flexural and impact strength of a high-impact (Lucitone 199) and a urethane-based denture material (Eclipse).Materials and methods: Flexural strength (64 x 10 x 3.3 mm) and impact strength (60 x 6 x 4 mm) specimens were made following the manufacturers' instructions and assigned to two groups (n = 10): control (C) - not thermocycled - and T - thermocycled (5000 cycles between 5 and 55 degrees C). Specimens were submitted to three-point bending and Charpy impact tests.Results: Flexural strength (MPa) and impact strength (kJ/m(2)) data were analysed with two-way ANOVA (p = 0.05). The flexural strength of material Eclipse (C, 136.5; T, 130.7) was significantly higher than that of resin Lucitone 550 (C, 99.4; T, 90.1). Material Eclipse exhibited significantly higher impact strength (C, 6.9; T, 5.3) than the resin Lucitone 550 (C, 3.5; T, 3.0). For both materials, a significant decrease in flexural and impact strengths was observed when the specimens were thermocycled.Conclusion: Flexural and impact strengths were higher for Eclipse than for Lucitone 550, in both groups. Thermocycling decreased the flexural and impact strengths of Eclipse and Lucitone 550.

Electrical conductivity of silicate glasses with tetravalent cations substituting Si

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Growth rates in modern speleothems from Santana Cave, Brazil, by the Pb-210-method

The Santana Cave is located at the Upper Ribeira Touristic State Park (PETAR-Parque Estadual Turistico do Alto Ribeira) in southern São Paulo State, Brazil. This paper describes Pb-210 activity concentration data in soda straw stalactites samples collected at Salao das Flores in Santana Cave that is a fossil tributary of the cave river. Non-expensive alpha counting following some analytical steps for extracting and depositing Pb-210 were used for providing the Pb-210 data. In the analyzed samples, Pb-210 values of increasingly older samples fitted an exponential curve, thus suggesting that the production of Pb-210 has been constant with time. Also, the near-ideal fit indicated that the growth was uniform and there was no break in the continuous growth. The soda straw growth rates were determined from the best fit to the exponential curve through the Pb-210 activity concentration. The results of the measurements allowed estimate a longitudinal rate corresponding to 1.3 mm/yr and a lateral rate of 0.01 mm/yr, which permitted calculate times of 70 years and 317-498 years for their formation, respectively. The lateral growth rate is compatible with values from studies of chemical weathering rates held under laboratory and natural conditions. (C) 2011 Elsevier Ltd. All rights reserved.

Structural study of thin films prepared from tungstate glass matrix by Raman and X-ray absorption spectroscopy

Thin films were prepared using glass precursors obtained in the ternary system NaPO(3)-BaF(2)-WO(3) and the binary system NaPO(3)-WO(3) with high concentrations of WO(3) (above 40% molar). Vitreous samples have been used as a target to prepare thin films. Such films were deposited using the electron beam evaporation method onto soda-lime glass substrates. Several structural characterizations were performed by Raman spectroscopy and X-ray Absorption Near Edge Spectroscopy (XANES) at the tungsten L(I) and L(III) absorption edges. XANES investigations showed that tungsten atoms are only sixfold coordinated (octahedral WO(6)) and that these films are free of tungstate tetrahedral units (WO(4)). In addition, Raman spectroscopy allowed identifying a break in the linear phosphate chains as the amount of WO(3) increases and the formation of P-O-W bonds in the films network indicating the intermediary behavior of WO(6) octahedra in the film network. Based on XANES data, we suggested a new attribution of several Raman absorption bands which allowed identifying the presence of W-O and W=O terminal bonds and a progressive apparition of W-O-W bridging bonds for the most WO(3) concentrated samples (above 40% molar) attributed to the formation of WO(6) clusters. (C) 2008 Elsevier B.V. All rights reserved.

Visible and near-infrared luminescent Eu3+ or Er3+ doped laponite-derived xerogels and thick films: Structural and spectroscopic properties

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Novos processos de reciclagem de chumbo

O processo pirometalúrgico convencional para a produção de chumbo metálico é comparado com dois novos processos ambientalmente não agressivos: o eletrohidrometalúrgico e fusão alcalina. O processo eletrohidrometalúrgico consiste em reduzir o tamanho das partículas dos compostos de chumbo e lixiviar os mesmos com uma solução ácida de fluoborato férrico. Neste ponto, o chumbo é dissolvido com os íons férricos sendo reduzidos a íons ferrosos. A solução resultante da lixiviação é bombeada para os compartimentos catódicos de uma célula eletrolítica de diafragma nos quais o chumbo metálico é depositado em catodos de aço inoxidável numa forma compacta e pura. A solução que é empobrecida em íons Pb2+ é então enviada aos compartimentos anódicos da mesma célula onde, nas superfícies de anodos ocorre a oxidação dos íons ferrosos a férricos, que retornam ao estágio de lixiviação. O processo de fusão alcalina consiste em se juntar soda cáustica fundida, enxofre e compostos de chumbo num reator a uma temperatura entre 600 °C e 700 °C. Como um resultado chumbo metálico é obtido juntamente com sais fundidos de sódio, sulfetos metálicos e borra. O fundido é processado, resultando em borra, sulfetos metálicos, soda cáustica e enxofre. Estes dois últimos retornam para o reator. Ambos os processos permitem a recuperação de metais como antimônio, estanho, enxofre e prata, que em processo convencional são perdidos na escória. Esses novos processos são ambientalmente corretos sem poluições severas de Pb e SO2. O chumbo metálico obtido é mais puro que aquele do processo convencional.