Influence of the size and amount of cork particles on the toughness of a structural adhesive

The inclusion of particles (nano or micro) is a method to improve the mechanical properties such as toughness of structural adhesives. Structural adhesives are known for their high strength and stiffness but also for their low ductility and toughness. There are many processes described in the literature to increase the toughness, being one of the most common the use of rubber particles. In the present study, natural micro particles of cork are used with the objective to increase the toughness of a brittle epoxy adhesive. The idea is for the cork particles to act like as a crack stopper leading to more energy absorption. The influence of the cork particle size and amount were studied. Particles of cork ranging from 38 to 250 µm were mixed in the epoxy adhesive Araldite 2020 from Huntsman. The amount of cork in the adhesive was varied between 1 and 5% in weight. Surface treatment (low pressure plasma) was applied to the cork powder to assess the effect of the interaction adhesive-cork with several degrees of adhesion

Taxonomic and nomenclatural notes on Guatteria australis (Annonaceae)

Guatteria is the largest genus of Annonaceae, comprising ca. 300 species. The genus presents taxonomic problems, and the number of species has been overestimated. Taxonomic revision, description, comments and illustration of G. australis are presented here. As a result, 41 names have been placed in synonymy under G. australis, and three lectotypes are newly designated

Absorção de fosfatos mono e diâmonico marcados com radiofósforo, em presença e ausência de uréia, pela parte aérea de mudas de abacaxizeiro (Ananas comosus (L.) Merr.)

One per cent (w/v) solutions of monoammonium and diammonium phosphates either in the presence or absence of 1% urea were applied in the axyl of the "D" leaves of young plants grown in soil filled pots. There was no statistical difference between the two P sources. On the other hand, the presence of urea showed tendency to decrease internal transport of the applied phosphates irrespective of the source used.O presente trabalho, desenvolvido em casa-de-vegetação com abacaxizeiro cultivar "Smooth cayenne", para observação do efeito de MAP e OAP com e sem uréia adicionados em solução a 1%, via axila da folha D, mostrou que: ambas as fontes tiveram efeitos semelhantes no suprimento de fósforo e a uréia não melhorou a eficiência de absorção, mostrando ainda uma tendência negativa na distribuição do 32p entre as partes estudadas

Estudos sobre a nutrição mineral do sorgo granífero: V. efeitos das deficiências de micronutrientes (nota)

Grain sorghum var. TEY-101 was grown in nutrient solution in the presence and in the absence of micronutrients. Symptoms of deficieny of all micronutrients were obtained. Growth, as measured by dry matter production was affected by the treatments in the folowing decreasing, order: minus Fe, minus Zn, minus Mn, minus B, minus Mo and minus Cu. An additional treatment in which excess Mn was used revealed a relative tolerance of the variety to high levels of this element. The results of chemical analyses of the leaves suggest that the following contents (in ppm) of micronutrients are associated with the respective deficiencies: B - 20 to 40, Cu - 8 to 10, Fe - 198, Mn - 32 to 35, Mo - 0.5, Zn - 46 to 52; in the case of Fe the Fe/Mn relationship seems to give a better indication of the nutritional status than the content of the element per se, being igual to 1.7 in the healthy plants, and 0.6 in the iron deficient ones.O sorgo granífero, var. TEY 101, foi cultivado em solução nutritiva na presença e ausência de micronutrientes. Foram obtidos sintomas de carência e foi feita a determinação dos teores desses elementos nas folhas

COVAD survey 2 long-term outcomes: unmet need and protocol

Vaccine hesitancy is considered a major barrier to achieving herd immunity against COVID-19. While multiple alternative and synergistic approaches including heterologous vaccination, booster doses, and antiviral drugs have been developed, equitable vaccine uptake remains the foremost strategy to manage pandemic. Although none of the currently approved vaccines are live-attenuated, several reports of disease flares, waning protection, and acute-onset syndromes have emerged as short-term adverse events after vaccination. Hence, scientific literature falls short when discussing potential long-term effects in vulnerable cohorts. The COVAD-2 survey follows on from the baseline COVAD-1 survey with the aim to collect patient-reported data on the long-term safety and tolerability of COVID-19 vaccines in immune modulation. The e-survey has been extensively pilot-tested and validated with translations into multiple languages. Anticipated results will help improve vaccination efforts and reduce the imminent risks of COVID-19 infection, especially in understudied vulnerable groups