Dissolved uranium, radium and radon evolution in the Continental Intercalaire aquifer, Algeria and Tunisia

Natural, dissolved U-238-series radionuclides (U, Ra-226, Rn-222) and activity ratios (A.R.s: U-234/U-238; Ra-228/Ra-226) in Continental Intercalaire (Cl) groundwaters and limited samples from the overlying Complexe Terminal (CT) aquifers of Algeria and Tunisia are discussed alongside core measurements for U/Th (and K) in the contexts of radiological water quality, geochemical controls in the aquifer, and water residence times. A redox barrier is characterised downgradient in the Algerian Cl for which a trend of increasing U-234/U-238 A.R.s with decreasing U-contents due to recoil-dominated U-234 solution under reducing conditions allows residence time modelling similar to 500 ka for the highest enhanced A.R. = 3.17. Geochemical modelling therefore identifies waters towards the centre of the Grand Erg Oriental basin as palaeowaters in line with reported C-14 and Cl-36 ages. A similar U-234/U-238 trend is evidenced in a few of the Tunisian CI waters. The paleoage status of these waters is affirmed by both noble gas recharge temperatures and simple modelling of dissolved, radiogenic He-4-contents both for sampled Algerian and Tunisian CI and CT waters. For the regions studied these waters therefore should be regarded as "fossil" waters and treated effectively as a non-renewable resource. (C) 2014 The Authors. Published by Elsevier Ltd.

The effect of self-adhesive and self-etching resin cements on the bond strength of nonmetallic posts in different root thirds

The purpose of this study was to evaluate the effect of self-adhesive and self-etching resin cements on the bond strength of nonmetallic posts in different root regions. Sixty single-rooted human teeth were decoronated, endodontically treated, post-space prepared, and divided into six groups. Glass-fiber (GF) posts (Exacto, Angelus) and fiber-reinforced composite (FRC) posts (EverStick, StickTeck) were cemented with self-adhesive resin cement (Breeze) (SA) (Pentral Clinical) and self-etching resin cement (Panavia-F) (SE) (Kuraray). Six 1-mm-thick rods were obtained from the cervical (C), middle (M), and apical (A) regions of the roots. The specimens were then subjected to microtensile testing in a special machine (BISCO; Schaumburg, IL, USA) at a crosshead speed of 0.5 mm/min. Microtensile bond strength data were analyzed with two-way ANOVA and Tukey's tests. Means (and SD) of the MPa were: GF/SA/C: 14.32 (2.84), GF/SA/M: 10.69 (2.72), GF/SA/A: 6.77 (2.17), GF/SE/C: 11.56 (4.13), GF/SE/M: 6.49 (2.54), GF/SE/A: 3.60 (1.29), FRC/SA/C: 16.89 (2.66), FRC/SA/M: 13.18 (2.19), FRC/SA/A: 8.45 (1.77), FRC/SE/C: 13.69 (3.26), FRC/SE/M: 9.58 (2.23), FRC/SE/A: 5.62 (2.12). The difference among the regions was statistically significant for all groups (p < 0.05). The self-adhesive resin cement showed better results than the self-etching resin cement when compared to each post (p < 0.05). No statistically significant differences in bond strengths of the resin cements when comparable to each post (p > 0.05). The bond strength values were significantly affected by the resin cement and the highest values were found for self-adhesive resin cement.

De um subproduto industrial para um produto destinado à alimentação animal: produção de biomassa bacteriana

A grande diversidade das atividades industriais ocasiona durante o processo produtivo a geração de resíduos sólidos, líquidos e gasosos, que podem poluir e/ou contaminar o solo, a água e o ar. Embora existam regulamentos para o descarte desses resíduos, a inobservância às regras, a ineficiência dos tratamentos despoluentes e a inoperância de órgãos fiscalizadores permitem que, ainda hoje, sejam lançados ao ambiente grandes cargas de poluentes. Isso se aplica às indústrias de alimentos de origem animal. Felizmente, a visão dos empresários do setor vem mudando, na medida em que a imagem de uma empresa que conta com produtos e processos ambientalmente responsáveis representa parte das estratégias competitivas atuais. O objetivo deste trabalho foi demonstrar como um efluente industrial pode ser transformado em matéria prima para a obtenção de um produto com valor comercial, utilizando tecnologias reconhecidas pela indústria e a atividade microbiana. O efluente foi obtido em indústria de abate e processamento de tilápias, apresentado (valores médios) pH = 9,4, DQO = 1.127 mg/L, óleos e graxas = 1.166 mg/L, nitrogênio total = 813 mg/L, coliformes a 30–35o C = 1,0x105 NMP/mL, coliformes a 45o C = 0,41 NMP/mL, bolores e leveduras = 4,6x103 UFC/mL e, ocasionalmente, contendo Salmonella sp e Aeromonas sp. Os tratamentos físicos aplicados ao efluente incluíram gradeamento, filtração (50µm) e pasteurização (65o C/30 min). O cultivo de Rubrivivax gelatinosus foi realizado sob anaerobiose em reatores de vidro durante 7 dias, em temperatura ambiente (30±5o C) e 2.000±500 lux. A recuperação da biomassa foi feita por filtração tangencial (0,2 µm; 1,5 bar), centrifugação (3.400 g/30 min; 5o C) e liofilização (-40o C) e a pulverização foi realizada manualmente. A produção de massa celular atingiu 0,18 g/L, com produtividade de 0,0634 g/L.dia. O processo promoveu redução de 52% na DQO, 48% em óleos e graxas e 22% no nitrogênio total, gerando um resíduo com pH 7,9, livre de bactérias patogênicas e, portanto, apto ao descarte. O produto obtido apresentou cor vermelho escuro (L = 22,42; C = 14,22; h = 25,48), 4,55% de umidade, 57,39% de proteína, 11,08% de extrato etéreo, 4,05% de matéria mineral, 3,03 mg/g de oxicarotenóides, 20,27 NMP/g de coliformes a 30–35o C, <1,0 NMP/g de coliformes a 45o C, 1,2x103 UFC/g de bolores e leveduras e ausência de microrganismos patogênicos. Essas características apontam para um potencial pigmentante e nutricional positivo no produto, que pode encontrar aplicação na produção animal, com segurança microbiológica. Dessa forma, fecha-se um ciclo autosustentável que pode ser adotado na própria fonte geradora do resíduo industrial, permitindo a reversão de gastos com tratamento despoluente em receitas advindas da comercialização de um novo produto.

The ability of Nile tilapia to regulate protein and energy intake evaluated by carbon relative enrichement

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Poultry offal meal in chicken: Traceability using the technique of carbon (C-13/C-12)- and nitrogen (N-15/N-14)-stable isotopes

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Atmospheric cosmic rays in the South Atlantic anomaly region

To study the production and propagation of fast secondaries particles in the atmosphere, data collected during eleven quiet-time balloon flights are analysed. Comparisons of these data with those obtained in different geomagnetic rigidity regions permit to estimate the contributions of the proton and electron components in the measured intensities. Derivations of this last component in the «upward» and «downward» moving electrons fluxes indicate that in the anomaly region a fraction of these particles, produced by the primary protons, are leaving the atmosphere and will not return to the Earth. © 1991 Società Italiana di Fisica.

Increased atmospheric carbon dioxide concentration: effects on eucalypt rust (Puccinia psidii), C:N ratio and essential oils in eucalypt clonal plantlets

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estimation of lower flammability limits of C-H compounds in air at atmospheric pressure, evaluation of temperature dependence and diluent effect

Estimation of the lower flammability limits of C-H compounds at 25 degrees C and 1 atm; at moderate temperatures and in presence of diluent was the objective of this study. A set of 120 degrees C H compounds was divided into a correlation set and a prediction set of 60 compounds each. The absolute average relative error for the total set was 7.89%; for the correlation set, it was 6.09%; and for the prediction set it was 9.68%. However, it was shown that by considering different sources of experimental data the values were reduced to 6.5% for the prediction set and to 6.29% for the total set. The method showed consistency with Le Chatelier's law for binary mixtures of C H compounds. When tested for a temperature range from 5 degrees C to 100 degrees C , the absolute average relative errors were 2.41% for methane; 4.78% for propane; 0.29% for iso-butane and 3.86% for propylene. When nitrogen was added, the absolute average relative errors were 2.48% for methane; 5.13% for propane; 0.11% for iso-butane and 0.15% for propylene. When carbon dioxide was added, the absolute relative errors were 1.80% for methane; 5.38% for propane; 0.86% for iso-butane and 1.06% for propylene. (C) 2014 Elsevier B.V. All rights reserved.