Estudo das alterações das propriedades mecânicas em aço A-516 grau 70 soldado e submetido a tratamento térmico de alívio de tensões

Pressure vessels are equipments that require a great care because of their high cost and human life risk in case of fail, and its fabrication methods are different for each manufacturer. Normally, pressure vessels and its parts are fabricated by welding, which may change local properties of metals. The head of a pressure vessel is a very important structural component and it is fabricated by welding and mechanical conformation. Because its excellent mechanical properties, de steel A-516 Grade 70 is often used in manufacturing of large pressure vessels that are subjected to high pressure and temperature, but was verified that its mechanical resistance is decreased when submitted to a tension relief heat treatment. By experience it was defined that before mechanical conformation of the head of a large pressure vessel, the steel should be submitted to a stress relief heat treatment in order to facilitate the mechanical conformation, but there is no quantitative analysis to prove this method and study its possible risks. In the present work the steel A-516 Grade 70 demonstrated a decrease of its mechanical resistance when submitted to a stress relief heat treatment, but keeping above the minimum limit defined in the literature. By other side its ductility was substantially increased, being possible to deduce that the stress relief heat treatment before mechanical conformation is a viable e recommended technique, but with reservations. With the data acquired during the fabrication e preparation of the specimen and the result of the tests, it was possible to elaborate a welding procedure that provides the same results obtained in this present work

Atitudes dos profissionais de enfermagem relacionadas ao Processo de Enfermagem

Os objetivos do estudo foram descrever a disposição sobre o Processo de Enfermagem (PE) e a percepção de poder clínico dos profissionais de enfermagem; analisar associações entre atitudes relacionadas ao PE e variáveis selecionadas. Participaram 1.605 auxiliares de enfermagem e enfermeiros (86,9% mulheres, idade média 44,12 anos; DP=9,55). O escore médio no instrumento Posições sobre o Processo de Enfermagem (PPE) foi 112,37 (DP=22,28) e no Power as Knowing Participation in Change Tool - versão brasileira (PKPCT) foi 281,12 (DP= 38,72). Os escores nos instrumentos foram mais altos para enfermeiros quando comparados aos auxiliares. Houve correlação positiva moderada entre escores do PPE e PKPCT. Para os auxiliares houve associação entre os escores no PPE, sexo e pós-graduação; e entre percepção de poder e sexo. Para os enfermeiros houve associação entre PKPCT e cargo de chefia. Mais estudos devem ser desenvolvidos com vistas a identificar variáveis potencialmente associadas ao uso do Processo de Enfermagem na prática clínica.

Shedding light on the role of the prokaryotic assemblage in the biogeochemical cycles of the dark ocean

Se han eliminado las páginas en blanco

Mesoscale eddies: Hotspots of prokaryotic activity and differential community structure in the ocean

[EN] To investigate the effects of mesoscale eddies on prokaryotic assemblage structure and activity, we sampled two cyclonic eddies (CEs) and two anticyclonic eddies (AEs) in the permanent eddy-field downstream the Canary Islands. The eddy stations were compared with two far-field (FF) stations located also in the Canary Current, but outside the influence of the eddy field. The distribution of prokaryotic abundance (PA), bulk prokaryotic heterotrophic activity (PHA), various indicators of single-cell activity (such as nucleic acid content, proportion of live cells, and fraction of cells actively incorporating leucine), as well as bacterial and archaeal community structure were determined from the surface to 2000m depth. In the upper epipelagic layer (0?200 m), the effect of eddies on the prokaryotic community was more apparent, as indicated by the higher PA, PHA, fraction of living cells, and percentage of active cells incorporating leucine within eddies than at FF stations. Prokaryotic community composition differed also between eddy and FF stations in the epipelagic layer. In the mesopelagic layer (200?1000 m), there were also significant differences in PA and PHA between eddy and FF stations, although in general, there were no clear differences in community composition or single-cell activity. The effects on prokaryotic activity and community structure were stronger in AE than CE, decreasing with depth in both types of eddies. Overall, both types of eddies show distinct community compositions (as compared with FF in the epipelagic), and represent oceanic ?hotspots? of prokaryotic activity (in the epi- and mesopelagic realms).

Significance of non‐sinking particulate organic carbon and dark CO2 fixation to heterotrophic carbon demand in the mesopelagic northeast Atlantic

[EN] It is generally assumed that sinking particulate organic carbon (POC) constitutes the main source of organic carbon supply to the deep ocean's food webs. However, a major discrepancy between the rates of sinking POC supply (collected with sediment traps) and the prokaryotic organic carbon demand (the total amount of carbon required to sustain the heterotrophic metabolism of the prokaryotes; i.e., production plus respiration, PCD) of deep-water communities has been consistently reported for the dark realm of the global ocean. While the amount of sinking POC flux declines exponentially with depth, the concentration of suspended, buoyant non-sinking POC (nsPOC; obtained with oceanographic bottles) exhibits only small variations with depth in the (sub)tropical Northeast Atlantic. Based on available data for the North Atlantic we show here that the sinking POC flux would contribute only 4–12% of the PCD in the mesopelagic realm (depending on the primary production rate in surface waters). The amount of nsPOC potentially available to heterotrophic prokaryotes in the mesopelagic realm can be partly replenished by dark dissolved inorganic carbon fixation contributing between 12% to 72% to the PCD daily. Taken together, there is evidence that the mesopelagic microheterotrophic biota is more dependent on the nsPOC pool than on the sinking POC supply. Hence, the enigmatic major mismatch between the organic carbon demand of the deep-water heterotrophic microbiota and the POC supply rates might be substantially smaller by including the potentially available nsPOC and its autochthonous production in oceanic carbon cycling models.

Un copista-autor : Francisco de Paula Castañeda en Doña María Retazos (1821-1823)

En el marco polifónico e intertextual de la construcción enunciativa del periódico Doña María Retazos (1821-1823), Francisco de Paula Castañeda formula una figura de autor que se expone como scriptor de antiguallas, operación devenida, paradójicamente, en la configuración de un autor moderno, es decir, un periodista