Microstructure and Property Modifications of Cold Rolled IF Steel by Local Laser Annealing

Metallurgical and Materials Transactions A - Laser annealing experiments are performed on cold rolled IF steel whereby highly localized microstructure and property modification are achieved. The...     

Phase transformations in nickel sulphide: Microstructures and mechanisms

Nickel sulphide inclusions are known to be responsible for delayed fracture in tempered glasses due to phase transformation within the inclusion. Microstructural identification of the phase transformation mechanisms in the Ni–S system close to the NiS composition were carried out on a series of partially transformed states. Observations allow to investigate the morphological evolution during transformation, the phase orientation relationships and the first stages of the transformation were investigated by optical microscopy, electron backscatter diffraction, and scanning and transmission electron microscopy. The transformation mechanisms change significantly with the change in sulphur content of the α-NiS phase. Massive transformation is observed for near-stoichiometric composition. For overstoichiometric composition, the transformation is controlled by a long-range diffusion mechanism. The influence of stoichiometry and impurities (Fe) on the microstructural evolution and transformation mechanisms has also been studied.     

An intuitive daylighting performance analysis and optimization approach

The effective integration of daylighting considerations into the design process requires many issues to be considered simultaneously, such as daily and seasonal variations, illumination, and thermal comfort. To address the need for early integration into the design process, a new approach called Lightsolve has been developed. Its key objectives are to support the design process using a goal-oriented approach based on iterative design improvement suggestions; to provide climate-based annual metrics in a visual and synthesized format; and to relate quantitative and qualitative performance criteria using daylighting analysis data in various forms. This methodology includes the development of a time-segmentation process to represent weather and time in a condensed form, the adaptation of daylight metrics that encompass temporal and spatial considerations, and the creation of an interactive analysis interface to explore design options and design iterations. This system relies on optimization techniques to generate these suggestions. Lightsolve allows the designer to explore other design alternatives that may better fulfil the objectives and to learn about appropriate strategies to resolve daylight or sunlight penetration issues. It offers architects and building engineers support for daylighting design that can be employed interactively within the existing design process.

L'intégration des aspects relatifs à l'éclairage naturel dans un projet d'architecture exige l'étude simultanée de nombreuses questions comme ses variations quotidiennes et saisonnières ou l'équilibre entre le niveau d'éclairement et le confort thermique. Afin de répondre à la nécessité d'une intégration rapide dans le processus de conception architecturale, une nouvelle approche baptisée Lightsolve a été mise au point. Ses principaux objectifs sont les suivants: guider le processus par une approche inverse s'appuyant sur des suggestions itératives d'amélioration du projet; fournir des paramètres annuels basés sur le climat sous forme visuelle et synthétique; mettre en relation les critères de performance quantitatifs et qualitatifs en utilisant diverses formes de données d'analyse d'éclairage naturel. Cette méthodologie inclut le développement d'un processus de segmentation temporelle permettant de représenter les conditions météorologiques ainsi que la date ou l'heure sous forme condensée; elle permet également d'englober des considérations temporelles et spatiales pour l'éclairage naturel et comprend la création d'une interface d'analyse interactive pour explorer les options et les itérations du projet dans sa phase conceptuelle. Ce système repose sur des techniques d'optimisation qui génèrent des suggestions de modifications. La méthode Lightsolve permet ainsi au concepteur d'explorer d'autres alternatives pour son projet, susceptibles de mieux atteindre les objectifs visés et de s'informer sur des stratégies appropriées permettant de résoudre des problèmes d'éclairage naturel et de penetration de la lumière directe du soleil. Elle offre aux architectes et aux ingénieurs en bâtiments une aide à la conception en éclairage naturel qui peut être utilisée de manière interactive, afin de ne pas perturber le processus de conception architecturale.

Mots clés: éclairage natural, processus de conception architecturale, aide à la conception, énergie, optimisation interactive, simulation, visualisation     

First-Principles Study of Lattice Dynamics and Thermal Properties of Alkaline-Earth Metal Nitrides CaN,SrN, and BaN

We have performed first-principles calculations to investigate the structural, electronic, magnetic, lattice dynamics, and thermodynamic properties of ferromagnetic alkaline earth metal nitrides CaN, SrN, and BaN in the rocksalt structure using the plane-wave pseudopotential approach to the density functional theory within local density and generalized gradient approximations for the exchange and correlation potential. The linear response to the density functional theory allowed us to calculate the phonon dispersion spectra for these compounds. We reported also the results on thermodynamic properties as a function of temperature calculated by using the quasiharmonic approximation.     

Application of semi-analytical finite element method to evaluate asphalt pavement bearing capacity

Bearing capacity is a key index in pavement management systems in many countries, which reflects the essential material properties of asphalt pavements. Many stationary measuring methods have been undertaken in the past; current assessment of the bearing capacity tends towards fast and continuous measurements at traffic speed for a network analysis. The conventional evaluation using stationary loads do not represent real traffic loading condition; therefore the results will inevitably lead to discrepancies from reality. A specific computational program SAFEM based on semi-analytical finite element method is proposed to overcome the difficulty. The reliability and efficiency of the SAFEM is proved by verification with commercial FE software ABAQUS and field measurements. The variation tendency of the back-calculated bearing capacity has a quite good negative linear relation with the number of loading cycles in the experiment. The investigation shows this proposed assessment system is a feasible option for the fast and reliable analysis of the pavement bearing capacity at a network level for road administrations.     

Is there a golden age in publication activity?—an analysis of age-related scholarly performance across all scientific disciplines

Scientometrics - We examined whether the publication characteristics of various scientific disciplines exhibit age-related trends. Our analysis was based on two large data sets comprising all major...