José Amarilio Barbosa

Ferroelectric characterization of aligned barium titanate nanofibres

We report the synthesis, structural and ferroelectric characterization of continuous well-aligned nanofibres of barium titanate produced by the electrospinning technique. The fibres with average diameter of 150–400 nm consist of connected nanoparticles of BaTiO3 stacked together to form the shape of a long filament. The tetragonal phase in the obtained nanofibres was revealed by the x-ray diffraction and Raman spectroscopy and has been also confirmed by the second harmonic generation (SHG) and piezoresponse force microscopy (PFM). The temperature dependence of the SHG in the vicinity of the paraelectric–ferroelectric phase transition suggests that barium titanate nanofibres are indeed ferroelectric with an apparent glass-like state caused by metastable polar nanoregions. The existence of domain structure and local switching studied by PFM present clear evidence of the polar phase at room temperature.

Assessment of land use efficiency using BSA tools : development of a new index

AbstractIn this article, the sustainability assessment of land use efficiency of buildings is subject to a critical study. Several building sustainability assessment (BSA) tools were analyzed, finding that the impacts of this criterion are not correctly assessed in current methodologies and some even ignore its importance. Some existing assessment methods and corresponding indexes were used in four virtual buildings to evaluate the effectiveness of each calculation method. It was concluded that the existing methods do not provide correct assessments and can promote unsustainable practices. It was also proved that it is necessary to include the implantation index, spatial efficiency, and occupational efficiency for correct assessments complementary to the use of the gross floor area index or development density. Due to difficulties in the weighting of the four complementary indexes, a single index was developed to perform the calculations using five main variables. The new index was tested in seven virtual...

Piezoelectric, nonliner optical, electro-optical, and pyroelectric properties of cesium hydrogen malate hydrate crystal

Cesium hydrogen L-malate monohydrate crystals are shown to be a promising material for several potential applications. The crystals display an exceptionally large piezoelectric coefficient, d22=23.7pm∕V. They are also an efficient generator of the optical second harmonic of near infrared light, being close to an order of magnitude more efficient than potassium diphosphate crystals. A relatively strong electro-optic response (the figure of merit 12∣n1r12−n3r32∣ was found to be 4.83pm∕V) and a reasonable pyroelectric coefficient (p2=2.5×10−4μC∕cm2K at 245K) are also observed.

Adaptation of SBToolPT to office buildings

The few available sustainability assessment tools applicable in Portugal are oriented for residential buildings. Nevertheless, the impacts of office buildings have been rising mainly due to an increase in the energy consumption for cooling and heating. This way, due to the growing environmental impact of office buildings, the development of Building Sustainability Assessment (BSA) tools to assess the sustainability of this type of buildings is necessary and important to guide and to boost the construction sector towards sustainable development. The main objective of this work was to develop a sustainability assessment tool aimed at office buildings based in SBToolPT-H. The work includes the definition of the tools framework and assessment method, as well as the Portuguese benchmarks and weighting system used in the aggregation. In order to promote the practical use of this tool, an evaluation guide was also developed in which there is detailed information about calculation methods and aggregation models....

Smart interior design of buildings and its relationship to land use

ABSTRACT Architectural design is often associated with aesthetics and style, but it is also very important to building performance and sustainability. There are some studies associating architectural design to the choice for materials from sustainable sources, to indoor air quality, to energy efficiency and productivity. This article takes a step further to analyse how the use of efficient interior design techniques can impact the habitable space in order to improve building sustainability in land use. Smart interior design, a current trend related to the use of efficient and flexible furniture and movable walls in tiny or compact apartments, is analysed. A building with a standard design is used as a case study reference building and compared to a proposed theoretical design alternative using smart interior design techniques. In order to correctly assess sustainability performance, a quantifiable and verified method is used. Results showed that the use of smart interior design techniques can greatly reduce buildings’ impact on the environment.

New approach addressing sustainability in urban areas using sustainable city models

A brief analysis of the environmental, social and economic paradigm of todays cities, allows a simple conclusion to be reached: current cities are not sustainable. Considering this, it is very important to study the causes of city problems and to develop city models implementing sustainability practices. There are a limited number of studies developing sustainable city models, but in the scientific community there is an even greater lack of studies about the rehabilitation of current cities to implement these models. This work emerges with the objective of analysing how it is possible to implement sustainability practices in cities through the development of a sustainable city model and an urban rehabilitation plan. The development of sustainable city models is a very complex topic and the analysis of the literature shows that it is necessary to consider the relation between environmental and social aspects in the development of sustainable cities, while taking special care when considering the economic ...