For the first time, ultrafiltration (UF) green membranes were prepared through a sustainable route by using PLA as a biopolymer and dihydrolevoclucosenone, whose trade name is Cyrene™ (Cyr), dimethyl isosorbide (DMI), and ethyl lactate (EL) as biobased solvents. The influence of physical-chemical properties of the solvent on the final membrane morphology and performance was evaluated. The variation of polymer concentration in the casting solution, as well as the presence of Pluronic^® (Plu) as a pore former agent, were assessed as well. The obtained results highlighted that the final morphology of a membrane was strictly connected with the interplaying of thermodynamic factors as well as kinetic ones, primarily dope solution viscosity. The pore size of the resulting PLA membranes ranged from 0.02 to 0.09 μm. Membrane thickness and porosity varied in the range of 0.090–0.133 mm of 75–87%, respectively, and DMI led to the most porous membranes. The addition of Plu to the casting solution showed a beneficial effect on the membrane contact angle, allowing the formation of hydrophilic membranes (contact angle < 90°), and promoted the increase of pore size as well as the reduction of membrane crystallinity. PLA membranes were tested for pure water permeability (10–390 L/m² h bar).

During processing of zirconia blocks, where they are used for different dental implants type, most of the loosed material as a powder is subsequently discarded. Besides damage to the environment, waste of material results in financial losses, resulting in higher final cost of treatment. The yttria stabilized zirconia (Y-TZP) has a variety of applications due to it is combination of high strength and fracture toughness. The objective was to reuse zirconia waste analyzing the effects of sintering temperature. The starting materials used in this study were two different powders of ceramic system ZrO₃-Y₂O₃: commercial zirconia nanoparticle and microparticle zirconia waste. The raw material was shaped by uniaxial and isostatic pressing and then sintered at 1500, 1550 and 1600 ° C over 1 hour. The X-ray diffraction (XRD) and dilatometry were used to powder characterization. After sintering density / porosity, flexural strength, and scanning electron microscopy (SEM) were realized .The waste showed similar values of density, and grain size to commercial material studied, confirming that it can be reused.

Este trabalho teve por objetivo analisar a viabilidade da produção de pisogramas de concreto com a incorporação de fibras de papel kraft provenientes de embalagens de cimento pós-uso. As embalagens foram coletadas e processadas, resultando nas fibras de papel kraft (FPK). Foi adotado o traço de referência de 1:2,31:2,49:0,54 nas proporções de massa de cimento, agregado miúdo, agregado graúdo e fator água/cimento, respectivamente. Estudou-se duas composições com incorporação de FPK nos percentuais de 0,5% e 1,0% em relação à massa total de agregados. Para cada composição, foram moldados 4 corpos de prova e executados os ensaios de absorção de água e resistência à compressão aos 28 dias. Como resultado, todas composições apresentaram absorção de água abaixo do limite normativo de 6%. No ensaio de resistência à compressão, as composições de referência, de 0,5% e de 1,0% de FPK obtiveram 35,55 MPa, 30,61 MPa e 28,40 MPa, respectivamente. Como o concreto com 0,5% de incorporação de FPK obteve melhor desempenho mecânico, foram confeccionados 6 pisogramas para realização da inspeção visual e avaliação dimensional, os quais atenderam aos requisitos normativos. Este trabalho mostra a viabilidade de produção de concreto com FPK e a utilização deste na fabricação de pisogramas para áreas que exijam até 30 MPa.

This paper presents the application of Design of Experiments (DOE) to an alkaline treatment in mordenite zeolite, in order to identify the optimum settings of the variables (temperature and concentration of NaOH) that promote greater desilication. Samples of commercial mordenite with Si / Al ratio = 9 have been treated with aqueuos NaOH solution of various concentration (0,1;0,5;1,0) and temperature (30,50,70°C). Statistical analysis was carried out based on a 2² factorial design with center point replicates. Seven experiments were executed and the data of Si/Al ratio obtained. The resulting samples were characterized by x-ray difraction (XRD) and energy dispersive x-ray (EDX), to identify the structures and crystalline phases, and to determine the percentages of silicon and aluminum, respectively. In all samples, a decrease in the Si / Al ratio was observed, keeping the crystalline structure. The treatment was most effective, especially, at high temperature and NaOH concentration (experiment 4). DOE was shown to be a powerful techinique for the study of the variables, allowing determining which variables and value ranges have more influence on response, enabling optimization.

Alumina-Glass compositions were prepared to evaluate the effect of glass as sintering aids. The composites showed densification below 1100°C. The highest density values (~95%) were obtained for compositions based respectively on borosilicate (G2 and G3) and soda lime glasses (G4), all [A1] [A2] containing Na in the precursor powder. Samples G1 (K-based) and G5 (no K or Na in the precursor glass powder) presented irregular morphology with the presence of intergranular porosity. The composition G2, G3, and G4 presented uniform morphology corresponding to higher densification.