Bulletin du Comité de l'Afrique française

1903 (A13).

Bulletin du Comité de l'Afrique française

1900 (A10).

Bulletin du Comité de l'Afrique française

1892 (A2).

Bulletin du Comité de l'Afrique française

1898 (A8).

Bulletin du Comité de l'Afrique française

1895 (A5).

Bulletin du Comité de l'Afrique française

1901 (A11).

Bulletin du Comité de l'Afrique française

1902 (A12).

Indicadores químicos de qualidade da matéria orgânica de solo da sub-bacia do Rio das Mortes sob manejos diferenciais de cafeeiro

This work evaluated the chemical quality of organic matter (OM) of a Brazilian Oxisol cultivated with coffee plants, under organic and conventional managements. Total organic C (TOC), light fraction C (LF-C) and C in humic (HA-C) and fulvic (FA-C) acids fractions was measured. Amongst the evaluated indexes, TOC and LF-C discriminated better OM attributes as a function of management. The stratification ratio (TOC5-10cm/TOC10-20cm) did not show differences between the systems studied. The organic system can contribute to the sustainability of coffee plantations in Brazil, because it maintains the chemical attributes of OM closer to the indexes verified under forest conditions.

De fatis scientiae chemicae sub epocha patrum

Invocatio: D.D.

De candela sub aquis ardente

Invocatio: Q.F.F.Q.S.

Avaliação da qualidade de sedimentos - estudo de caso: sub-bacia do Ribeirão Espírito Santo, afluente do Rio São Francisco

This study evaluated the environmental impact resulting from surface water and sediment contamination by metals in a watershed affected by a tailing basin that controls effluents coming from a zinc-ore beneficiation plant. The studies combined assessments of sediment chemistry (exceedances of sediment quality guidelines), benthic assemblage structure and acute and chronic ecotoxicity. The results showed that the levels of metal contamination in sediments are not yet enough to cause deleterious effects to the biota. However, the ecotoxicity tests indicated the occurrence of chronic effects, demonstrating that other factors, as the use of fertilizers, could also be a source of contamination.

Indicia mineralogiae in Fennia sub gentilismo

Invocatio: I.N.D.

An mysterium S.S. Trinitatis veteribus Scandianis sub gentilismo fuerit cognitum?

Invocatio: I.N.D.O.M.

COMPARISON BETWEEN ASPHALTENES (SUB)FRACTIONS EXTRACTED FROM TWO DIFFERENT ASPHALTIC RESIDUES: CHEMICAL CHARACTERIZATION AND PHASE BEHAVIOR

Asphaltenes are blamed for various problems in the petroleum industry, especially formation of solid deposits and stabilization of water-in-oil emulsions. Many studies have been conducted to characterize chemical structures of asphaltenes and assess their phase behavior in crude oil or in model-systems of asphaltenes extracted from oil or asphaltic residues from refineries. However, due to the diversity and complexity of these structures, there is still much to be investigated. In this study, asphaltene (sub)fractions were extracted from an asphaltic residue (AR02), characterized by NMR, elemental analysis, X-ray fluorescence and MS-TOF, and compared to asphaltene subfractions obtained from another asphaltic residue (AR01) described in a previous article. The (sub)fractions obtained from the two residues were used to prepare model-systems containing 1 wt% of asphaltenes in toluene and their phase behavior was evaluated by measuring asphaltene precipitation onset using optical microscopy. The results obtained indicated minor differences between the asphaltene fractions obtained from the asphaltic residues of distinct origins, with respect to aromaticity, elemental composition (CHN), presence and content of heteroelements and average molar mass. Regarding stability, minor differences in molecule polarity appear to promote major differences in the phase behavior of each of the asphaltene fractions isolated.

Discursus chorographicus de terris Hyperboreis seu polo arctico vicinis, quem, ex C. Julii Solini polyhist. cap. XXI, verbis: Fabula erat de Hyperboreis ... sub moderamine ... Caroli Lithman, ... nec non venerandi consistorij approbatione, in florente Gymnasio Stregnesiano, die 26. Maij anni 1680, aequo bonorum examini ventilandum obtulit Jonas Grimsteen, respondente Andrea Bolino

Dedicated to: Petro Wreman, Leonhardo Gadd, Olao J. Hidingio, Samueli Jonson.