There is increasing interest in the ceramic industry in the development of pigments with intense tonalities that can be produced from low-cost alternative raw materials and also can fulfill technological and environmental requirements. This work reports on the preparation and characterization of CdS yellow ceramic pigment derived from Ni-Cd batteries through an acid leaching process. Cadmium was chemically extracted with HCl and tributylphosphate (TBP) and reacted with H2S to form CdS. The obtained yellow powder is composed of agglomerated particles with nanometer sizes and hexagonal and rod-shaped crystals. Rietveld refinement indicated that these particles consist of cubic and hexagonal CdS. CIELab colorimetric parameters revealed a bright yellow color (L*=77.8, a*=13.7 and b*=76.2), similar to that of commercial Cd Yellow pigment. The extraction of Cd from Ni-Cd batteries could be a low-cost and environmentally friendly solution for the production of CdS-based ceramic pigments.

Abstract This work investigates fluid mechanics and structural properties inside bacterial cellulose hydrogels in from of macroscopic anisotropic ellipsoid body cocoon-like 3D scaffolds. The hydrogels were evaluated by injections of iopamidol, a radiopaque medium used in medical radiological procedures. Results showed that hydromechanical behavior of BC hydrogels may be used to characterize its internal structure. It is suggested that internal barriers and flow distribution anisotropy may be used to develop novel therapeutic applications based on the tissue engineered multifunctional possibilities of the biomaterial.

A necessidade de novos recursos em cardiologia tem direcionado a Engenharia de Tecidos ao desenvolvimento de vasos sanguíneos artificiais que atendam aos requisitos do organismo. Neste trabalho, estruturas tubulares de celulose bacteriana (CB) foram produzidas e sua degradação in vitro foi avaliada. Através de microscopia eletrônica de varredura constatou-se que não houve alterações significativas na microestrutura e morfologia das fibras de CB após ensaios de degradação. Os ensaios de degradação em soluções fisiológicas PBS e salina revelaram uma degradação substancialmente baixa após 20 semanas. A baixa velocidade de degradação dos vasos é de grande importância, visto que o processo para a formação de novos vasos (angiogênese) demanda tempo.

The need of new techniques in cardiology has driven Tissue Engineering towards the development of artificial blood vessels that fulfill the requirements of the organism. In this work bacterial cellulose (BC) tubular structures were produced and their degradation in vitro was evaluated. No significant changes in microstructure and BC fiber morphology were observed by scanning electron microscopy after degradation tests. Degradation tests in physiological solutions (PBS and saline) revealed a very low degradation after 20 weeks. A low degradation rate of artificial vessels is important, since the process of new blood vessel formation (angiogenesis) demands time.

The synthesis of the ceramic pigment Victoria Green (Ca3Cr2Si3O12 ) is described. As raw materials CaCO3, Cr2O3, and SiO2 obtained from rice husk were used. Borax was used as mineralizer. Raw materials were formulated stoichiometrically and calcined from 1000 to 1200 ºC for 180 min. The main phase detected was uvarovite with particle size below 45 mm. The pigments were applied on ceramic tiles and sintered at 1150 ºC for 40 min. The synthesis process showed to be adequate to produce the green pigment, whose characteristics resemble those of a commercial pigment.

Characterization of the thermal decomposition of polyurethane (PUR) foams was performed by Fourier-transformed infrared (FT-IR) spectroscopy and thermogravimetric analysis (TGA). Three main weight loss paths were observed by TGA, the residue being lower than 3 wt.% for 3 different PUR foams analyzed. FT-IR spectra indicated CO2, CO, NH3 and isocyanides as main decomposition products. PUR foams of different cell sizes were immersed in a slurry of the parent glass ceramic of composition Li2O-ZrO2-SiO2-Al 2O3 (LZSA) and submitted to heat treatment. The LZSA cellular glass ceramics obtained after sintering and crystallization resembled the original morphology of the PUR foams.