No abstract

Seeks to integrate the complete design process beginning with a design created with the mathematical perception of fractal geometry, followed by the introduction of these images into CAD systems and its adjustment to the technical and aesthetic limitations of the printing industry. The result is an artwork created on a pure mathematical basis using the most recent techniques of computer‐aided textile design.

Urbanism and communities centralization enlarges atmospheric pollution that affects both human beings as well as their constructed buildings. Different scientific and technological studies are being conducted, both in academic and construction industry, aiming the development of new construction materials with properties that can decrease visual pollution of cities, reducing also the number of cleanings required. The present research work aims the study and the production of self-cleaning ceramic surfaces in an economical and viable way without changing aesthetical aspect of material substrates used. The use of TiO2 nanoparticles (TiO2-NNPs) represents an attractive way to generate self-cleaning surfaces, therefore promoting the degradation of pollutant agents and reducing cleaning maintenance costs. In order to impart self-cleaning properties to ceramic surfaces, TiO2-NNPs based layers were deposited on different ceramic material substrates using the dip-coating method. The Photocatalytic activity (degradation of pollutants adsorbed on the surface) of the TiO2-NNPs based layers was characterized via the decomposition rate of an aqueous solution of Methylene blue (MB) under UV light irradiation. Colourless layers were successfully produced onto gray and white ceramic substrates using this sol-gel technique, without changing their aesthetical appearance. It was observed that the best photocatalytic activity was exhibited by the most porous ceramic substrate (gray); nevertheless, all the TiO2-NNPs coated ceramic surfaces showed good photocatalytic efficiency.

Microencapsulated organic thermochromic pigments may have varied industrial applications, such as in windows and greenhouse roofs. Two black coloured commercial microencapsulated pigments from A and B brands are used in this work. The study is conducted with UVA irradiation, and simulation of atmospheric conditions (weathering tester QUV). After a few degradation cycles, the colour of the substrate becomes a yellowish hue, which suggests that chemical degradation of the components of the microcapsule has occurred. Some tests that include DSC are carried out in order to obtain information on the composition of the microcapsules.Extraction with organic solvents provides several fractions that are analysed by 1 H-NMR and IR. It is concluded that the material of the microcapsules is melamine formaldehyde and two of the core components are probably crystal violet and benzotriazole, which are assumed to act as a UV absorber and promoter of proton transfer. SEM analyses of the pigments before and after degradation show that the microcapsules maintain their shape. A study is also implemented on the effect of adding DABCO to the suspensions of the pigments, which are then irradiated with UV light. A somewhat protecting effect is observed.

Fibrous structures based on natural fibers have gained a key space when it is required to perform functions like separation, drainage, filtration, protection and soil reinforcement. The use of natural fibers turns engineering work more sustainable, since they are renewable, biodegradable, energy efficient and non-toxic raw materials. In this work, the influence of degradation caused by UV rays, heat and moisture on the mechanical behavior of vegetal natural fibers used in geotextiles, including sisal, coir and banana fibers, was studied. Natural fibers have been subjected to accelerate aging agents using QUV equipment and to real conditions, in contact with soil over a 3 months period. Samples were removed every 15 days and their mechanical behaviour evaluated under tensile. Moreover, the morphological modifications in the fibers structure have been also analyzed using SEM. The results show a significant degradation over the first 15 days for all types of fibers used. Sisal and banana fibers subjected to degradation in soil, present higher tensile strength loss over time than fibers subjected to accelerate aging tests in QUV. For geotextiles design, important remarks from the results can be obtained including: banana fibers are quite degraded by aging and soil conditions making them difficult to be applied in geotechnical engineering; sisal and coir fibers present high potential to perform various functions in contact with soil.