Abstract The physical and mechanical properties of foamed geopolymers were determined. The geopolymers were made with two different metakaolins (from Metacaulim do Brasil - MB, and Pantano Grande/RS - MPG) as precursors, with NaOH and Na2SiO3 as activators, and with the addition of foam, which was produced with the foaming agent diethanolamide of coconut fatty acid with a minimum of 80% concentration. Also, two times (2.5 and 4 h) were used for the calcination of MPG at 750 °C. The results showed that all factors (precursors type, alkali content, silica modulus, and foam content) had a significant influence on the response variables, which presented the following variations: compressive strength of 0.36 to 3.23 MPa; thermal conductivity from 0.22 to 0.42 W/(m.K); saturated bulk density from 1176 to 1364 kg/m3; dry bulk density of 619 to 864 kg/m3; air void from 46.4% to 62.5%; and water absorption from 55.7% to 95.4%. It was also concluded that the precursor type was the factor that had the most influence on the properties of foamed geopolymers, with MPG calcined for 4 h being the best, as greater compressive strength and low thermal conductivity were obtained.

Abstract Most books on Thermodynamics explain what thermodynamic potentials are and how conveniently they describe the properties of physical systems. Certain books add that, to be useful, the thermodynamic potentials must be expressed in their “natural variables”. Here we show that, given a set of physical variables, an appropriate thermodynamic potential can always be defined, which contains all the thermodynamic information about the system. We adopt various perspectives to discuss this point, which to the best of our knowledge has not been clearly presented in the literature.

Studies on the occurrence of Cryptosporidium spp. in cats are still scarce. In this literature review, we address epidemiological and clinical aspects, as well as diagnostic methods, therapeutic behavoiur, and control and prevention measures for this disease in cats, with the aim of investigating if cryptosporidiosis is an underestimated disease in the laboratory routine and in small animal medical clinics.

Estudios científicos acerca de la presencia de Cryptosporidium spp. en los gatos son escasos. En esta revisión bibliográfica se tratan los aspectos epidemiológicos y clínicos, así como los métodos de diagnóstico, la conducta terapéutica, y las medidas de control y prevención de la cryptosporidiosis en el gato doméstico, con el objetivo de establecer si se trata de una enfermedad subestimada en la rutina de laboratorio y en la clínica de pequeños animales.