We have conducted a survey of young single and multiple systems in the Taurus-Auriga star-forming region with the Atacama Large Millimeter Array (ALMA), substantially improving both the spatial resolution and sensitivity with which individual protoplanetary disks in these systems have been observed. These ALMA observations can resolve binary separations as small as 25-30 AU and have an average 3σ detection level of 0.35 mJy, equivalent to a disk mass of 4 × 10 −5 M for an M3 star. Our sample was constructed from stars that have an infrared excess and/or signs of accretion and have been classified as Class II. For the binary and higher order multiple systems observed, we detect λ = 1.3 mm continuum emission from one or more stars in all of our target systems. Combined with previous surveys of Taurus, our 21 new detections increase the fraction of millimeter-detected disks to over 75% in all categories of stars (singles, primaries, and companions) earlier than spectral type M6 in the Class II sample. Given the wealth of other information available for these stars, this has allowed us to study the impact of multiplicity with a much larger sample. While millimeter flux and disk mass are related to stellar mass as seen in previous studies, we find that both primary and secondary stars in binary systems with separations of 30 to 4200 AU have lower values of millimeter flux as a function of stellar mass than single stars. We also find that for these systems, the circumstellar disk around the primary star does not dominate the total disk mass in the system and contains on average 62% of the total mass.

ResumoLigas de alumínio possuem, dentre diversas propriedades, uma atrativa combinação entre resistência mecânica e densidade, característica que leva à utilização cada vez maior desses materiais em setores estratégicos, como as indústrias aeronáutica e automobilística. O aumento da resistência dessas ligas, por sua vez, está associado ao tratamento de endurecimento por precipitação, podendo ainda ser influenciado pelo encruamemto do metal, esse último decorrente da eventual realização de deformação plástica entre as etapas de solubilização e envelhecimento do referido processamento. Dentro desse contexto, neste trabalho foi avaliado o comportamento mecânico de amostras da liga de alumínio 7.075 submetidas à compressão monotônica e cíclica após a etapa de solubilização do tratamento de endurecimento por precipitação. O comportamento do material foi analisado através de ensaios de dureza. Os resultados evidenciaram os efeitos das características e da magnitude da deformação na propriedade mecânica da liga. Palavras-chave: Deformação; Endurecimento por precipitação; Liga de alumínio. INFLUENCE OF MONOTONIC AND CYCLIC STRAIN ON THE MECHANICAL BEHAVIOR OF AN ALUMINUM ALLOY SUBMITTED TO PRECIPITATION HARDENING HEAT TREATMENT AbstractAluminum alloys have, among several properties, an attractive combination of strength and density, which leads to an increased use of these materials in strategic sectors, such as aeronautical and automotive industries. The significant increase of strength in these alloys is usually associated with the precipitation hardening heat treatment, and may also be influenced by work hardening, the latter resulting from plastic deformation between the solution treatment and aging. In his study the mechanical behavior of 7075 aluminum alloy samples subjected to monotonic and cyclic compression after solution treatment was evaluated. The behavior of the material was analyzed through hardness tests. The results showed the effects of the characteristics and the magnitude of the strain in the mechanical property of the aluminum alloy.