Effect of Na-chloride on the bioleaching of a chalcopyrite concentrate in shake flasks and stirred tank bioreactors

Oxidative dissolution of chalcopyrite at ambient temperatures is generally slow and subject to passivation, posing a major challenge for developing bioleaching applications for this recalcitrant mineral. Chloride is known to enhance the chemical leaching of chalcopyrite, but much of this effect has been demonstrated at elevated temperatures. This study was undertaken to test whether 100-200 mM Na-chloride enhances the chemical and bacterial leaching of chalcopyrite in shake flasks and stirred tank bioreactor conditions at mesophilic temperatures. Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans and abiotic controls were employed for the leaching experiments. Addition of Na-chloride to the bioleaching suspension inhibited the formation of secondary phases from chalcopyrite and decreased the Fe(III) precipitation. Neither elemental S nor secondary Cu-sulfides were detected in solid residues by X-ray diffraction. Chalcopyrite leaching was enhanced when the solution contained bacteria, ferrous iron and Na-chloride under low redox potential (< 450 mV) conditions. Scanning electron micrographs and energy-dispersive analysis of X-rays revealed the presence of precipitates that were identified as brushite and jarosites in solid residues. Minor amounts of gypsum may also have been present. Electrochemical analysis of solid residues was in concurrence of the differential effects between chemical controls, chloride ions, and bacteria. Electrochemical impedance spectroscopy was used to characterize interfacial changes on chalcopyrite surface caused by different bioleaching conditions. In abiotic controls, the impedance signal stabilized after 28 days, indicating the lack of changes on mineral surface thereafter, but with more resistive behavior than chalcopyrite itself. For bioleached samples, the signal suggested some capacitive response with time owing to the formation of less conductive precipitates. At Bode-phase angle plots (middle frequency), a new time constant was observed that was associated with the formation of jarosite, possibly also with minor amount or elemental S, although this intermediate could not be verified by XRD. Real impedance vs. frequency plots indicated that the bioleaching continued to modify the chalcopyrite/solution interface even after 42 days. © 2013 The Authors.

Desenvolvimento de produto tipo shake utilizando farinha de tremoço doce (Lupinus albus) CV multolupa, decorticada e desengordurada

Pós-graduação em Alimentos e Nutrição - FCFAR

A universalidade poética de Rilke na formação do Grupo dos Novos: tradução e confluências na Amazônia brasileira

Esta dissertação objetiva pensar os desdobramentos que as traduções da poesia de Rainer Maria Rilke alcançaram no cenário do Suplemento Literário da Folha do Norte - SL/FN e em outros periódicos das décadas de 1940 e 1950, em que foram publicadas. Consideramos que estas traduções foram um indício de intensificação da abertura universalizante das letras paraenses às novidades modernistas iniciadas na Semana de Arte Moderna de 1922. Tais traduções foram cruciais para a formação do Grupo dos Novos, composto principalmente de nomes como Benedito Nunes, Mário Faustino e Paulo Plinio Abreu, além do antropólogo alemão Peter Paul Hilbert. O suporte teórico-metodológico será a utilização dos conceitos de Weltliteratur (Literatura universal) de Goethe e Reflexionsmedium (Médium-de-reflexão) de Benjamin. Estas matrizes interligarão os campos da história, da filosofia da linguagem e da tradução para refletirmos sobre o impacto dessas traduções na Amazônia brasileira da época. Outro conceito importante nesta dissertação é o de Bildung (formação), pensado a partir da leitura de Antoine Berman quando ele o relaciona à tradução, incluindo vários fenômenos que envolvem as relações tradutórias entre culturas e línguas. Ao final, por meio da reflexão tradutológica de Haroldo de Campos, visamos observar possíveis confluências nas produções poéticas e críticas de Mário Faustino, Manuel Bandeira e Paulo Plínio Abreu, como resultante do processo relacional promovido por estas traduções.

Effect of the consumption of a symbiotic shake on the intestinal microflora of erdely people

The consumption of foods containing probiotic and prebiotic ingredients is growing consistently every year, and in view of the limited number of studies investigating their effect in the elderly. Objective The objective of this study was to evaluate the effect of the consumption of a symbiotic shake containing Lactobacillus acidophilus, Bifidobacterium bifidum and fructooligosaccharides on glycemia and cholesterol levels in elderly people. Methods A randomized, double-blind, placebo-controlled study was conducted on twenty volunteers (ten for placebo group and ten for symbiotic group), aged 50 to 60 years. The criteria for inclusion in the study were: total cholesterol > 200 mg/dL; triglycerides > 200 mg/dL and glycemia > 110 mg/dL. Over a total test period of 30 days, 10 individuals (the symbiotic group) consumed a daily dose of 200 mL of a symbiotic shake containing 108 UFC/mL Lactobacillus acidophilus, 108 UFC/mL Bifidobacterium bifidum and 2 g oligofructose, while 10 other volunteers (the placebo group) drank daily the same amount of a shake that did not contain any symbiotic bacteria. Blood samples were collected 15 days prior to the start of the experiment and at 10-day intervals after the beginning of the shake intake. The standard lipid profile (total cholesterol, triglycerides and HDL cholesterol) and glycemia, or blood sugar levels, were evaluated by an enzyme colorimetric assay. Results The results of the symbiotic group showed a non-significant reduction (P > 0.05) in total cholesterol and triglycerides, a significant increase (P < 0.05) in HDL cholesterol and a significant reduction (P < 0.05) in fasting glycemia. No significant changes were observed in the placebo group. Conclusion The consumption of symbiotic shake resulted in a significant increase in HDL and a significant decrease of glycemia.

Generating Realistic Camera Shake for Virtual Scenes

When depicting both virtual and physical worlds, the viewer's impression of presence in these worlds is strongly linked to camera motion. Plausible and artist-controlled camera movement can substantially increase scene immersion. While physical camera motion exhibits subtle details of position, rotation, and acceleration, these details are often missing for virtual camera motion. In this work, we analyze camera movement using signal theory. Our system allows us to stylize a smooth user-defined virtual base camera motion by enriching it with plausible details. A key component of our system is a database of videos filmed by physical cameras. These videos are analyzed with a camera-motion estimation algorithm (structure-from-motion) and labeled manually with a specific style. By considering spectral properties of location, orientation and acceleration, our solution learns camera motion details. Consequently, an arbitrary virtual base motion, defined in any conventional animation package, can be automatically modified according to a user-selected style. In an animation package the camera motion base path is typically defined by the user via function curves. Another possibility is to obtain the camera path by using a mixed reality camera in motion capturing studio. As shown in our experiments, the resulting shots are still fully artist-controlled, but appear richer and more physically plausible.

Gundolf über Rilke [Rezension]

Lutz Weltmann

Rilke, Hüftbild

Signatur des Originals: S 36/F01644