Relation between kinetic parameters for reactions of organic matter degradation in waste environmental matrix

The organic fraction of urban solid residues disposed of in sanitary landfills during the decomposition yields biogas and leachate, which are sources of pollution. Leachate is a resultant liquid from the decomposition of substances contained in solid residues and it contains in its composition organic and inorganic substances. Literature shows an increase in the use of thermoanalytical techniques to study the samples with environmental interest, this way thermogravimetry is used in this research. Thermogravimetric studies (TG curves) carried out on leachate and residues shows similarities in the thermal behavior, although presenting complex composition. Residue samples were collected from landfills, composting plants, sewage treatment stations, leachate, which after treatment, were submitted for thermal analysis. Kinetic parameters were determined using the Flynn-Wall-Ozawa method. In this case they show little divergence between the kinetic parameter that can be attributed to different decomposition reaction and presence of organic compounds in different phases of the decomposition with structures modified during degradation process and also due to experimental conditions of analysis.

Dissolved organic carbon in rainwater from areas heavily impacted by sugar cane burning

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Waveguides and gratings fabrication in zirconium-based organic/inorganic hybrids

Sol-gel derived poly(oxyethylene)/siloxane organic/inorganic di-ureasil hybrids containing different amounts of methacrylic acid (McOH, CH(2)=C(CH(3))COOH)) modified zirconium oxo-clusters (Zr-OMc) were processed as thin films deposited in glassy substrates via spin coating and as transparent and shape controlled monoliths. Channel monomode waveguides and diffraction gratings were UV patterned using the Talbot interferometer and the Lloyd mirror interferometer experimental setups. The time dependence of the diffraction gratings efficiency was studied for hybrids containing different amounts of Zr-OMc. Finally, the number of propagating modes and the refractive index gradient within the waveguide region, determined as a Gaussian section located below the patterned channel, was evaluated and modeled, a maximum index contrast of 2.43 X 10(-5) being estimated.

Effect of dietary organic selenium and zinc on the internal egg quality of quail eggs for different periods and under different temperatures

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of organic selenium and zinc on the performance and egg quality of Japanese quails

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Gravimetric determination of soil organic matter

Avaliou-se o método de determinação gravimétrica da matéria orgânica do solo pela perda de massa por incineração a 300ºC e comparou-se com o carbono determinado pelo método Walkley-Black. Os dois métodos foram correlacionados positivamente com a seguinte equação de regressão linear: y = 3,720x + 0,2914. r = 0,937. O coeficiente. 3,720 foi maior do que os encontrados na literatura. que variaram de 1,68 a 2,13. Esta diferença foi atribuída ao maior grau de oxidação da matéria orgânica dos solos das regiões tropicais. O método de incineração é aplicável para determinação do C do solo em rotina. O método não contamina o meio ambiente com metal tóxico (Cr6+) e não oferece riscos aos analistas com o uso de ácido sulfúrico concentrado.

Efficiency of bioaugmentation in the removal of organic matter in aquaculture systems

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Gastrointestinal helminths in calves and cows in an organic milk production system

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Organic acid profile of commercial sour cassava starch

A presença de ácidos orgânicos no polvilho azedo, além de contribuir com aspectos como sabor e aroma, tem, conforme a literatura indica, correlação com a propriedade de expansão, que é um fator determinante no uso alimentício. Amostras de polvilho azedo foram coletadas nas Regiões Sul e Sudeste diretamente nas empresas ou no comércio. Foram preparadas para análise em cromatografia líquida de alta eficiência (CLAE), sendo que o cromatógrafo estava equipado com coluna Biorad Aminex HPX-87H para análise de ácidos orgânicos e detector refratométrico. As condições de análise envolveram o emprego da fase móvel ácido sulfúrico 0,005M, fluxo de 0,6 ml/min e temperatura da coluna de 60oC. Os ácidos quantificados foram lático (0,036 a 0,813 g/100g), acético (0 a 0,068 g/100g), propiônico (0 a 0,013 g/100g) e butírico (0 a 0,057 g/100g), presentes na fermentação natural. Os resultados revelaram grande variação entre as amostras, com diferenças mesmo dentro das Regiões. Algumas amostras apresentaram quantidades elevadas de ácidos, especialmente do ácido lático, mas nestas amostras os ácidos propiônico e butírico não foram detectados. A ausência do ácido butírico não era esperada, uma vez que esse ácido está diretamente relacionado com o aroma característico do polvilho azedo. O fato pode sugerir que a obtenção de algumas das amostras estudadas pode ter ocorrido sem o processo fermentativo natural.

The sensitization of the ligand-field state of the hexaammineruthenium(II) complex ion by organic compounds

The sensitized photolysis of [Ru(NH3)(6)](2+) by the organic dye rhodamine B and biacetyl was studied under conditions in which only the sensitizer absorbs. The reaction products resulting from ammonia aquation and Ru(II) to Ru(III) oxidation are the same for direct and sensitized photolysis. The energy transfer rate constant, calculated from the fluorescence quenching of rhodamine B, is similar to that estimated from the limiting quantum yield of the photosensitized photoaquation of the complex. Both reactions originate from a common reactive low-lying ligand-field (LF) state, which is also responsible for the direct photolysis reactions. This state, which leads directly to photoaquation, seems to have a certain charge transfer to solvent (CTTS) character, which is responsible for the photo-oxidation products. Sensitization is effective with rhodamine B (17 450 cm(-1)) and biacetyl (19 000 cm(-1)), whereas no reaction is observed with neutral red (16 900 cm(-1)). These results show that the excited state responsible for the photochemical reactions lies in the energy range between 16 900 cm(-1) and 17 700 cm(-1) and possesses spin-orbit character.

Low optical loss planar waveguides prepared in an organic-inorganic hybrid system

HfO2-(3-glycidoxipropil)trimethoxisilane (GPTS) planar waveguides were prepared by a sol-gel route. A stable sol of Hafnia nanocrystals was prepared and characterized by photon correlation spectroscopy and high resolution transmission electron microscopy. The suspension was incorporated in GPTS host and the resulting sol was deposited on borosilicate substrates by the spin coating technique. Optical properties such as refractive index, thickness, number of propagating modes, and attenuation coefficient were measured at 632.8, 543.5, and 1550 nm by the prism coupling technique as a function of the HfO2 content. (C) 2000 American Institute of Physics. [S0003-6951(00)03348-9].

Comparative procedures for the sample decomposition of rocks used in organic agriculture and the determination of Cu, Fe, Mn, and Zn by FAAS

The aim of this work was to develop an appropriate sample preparation procedure for the flame atomic absorption spectrometry determination of Cu, Fe, Mn, and, Zn in rocks used in organic agriculture as a source of macro- and micronutrients.Six different procedures were evaluated and are classified into three groups: (a) pressure digestion system with Teflon bombs, (b) conventional wet digestion in a digester heating block, and (c) closed microwave system with pressure and temperature control.Two standard reference materials and two commercial samples were analyzed. It was found that the closed microwave system required low reagent consumption, less time, and resulted in low contamination.

Ultrastructural evidences of the occurrence of digestion and absorption of organic solutes in bees ileum (Melipona quadrifasciata anthidioides - Hymenoptera, Apidae)

The ultrastructural aspects of the ileum of Melipona quadrifasciata anthidioides, a stingless bee whose workers obtain their protein requirements from pollen, present morphological evidences of digestion and absorption. These evidences are represented by special relationships between food particles and the bacterial nora present and between their assemblage and the ileum wall, mainly in the ileum three anterior fourths. The apical features of the epithelium also are indicative of organic material absorption.

Planar and UV written channel optical waveguides prepared with siloxane poly(oxyethylene)-zirconia organic-inorganic hybrids. Structure and optical properties

Organic-inorganic hybrids were prepared using ureapropyltriethoxysilane, methacryloxypropyltrimethoxysilane and acrylic acid modified zirconium(IV) n-propoxide precursors and were characterized by small angle X-ray scattering, X-ray diffraction and photoluminescence spectroscopy. The results indicate an effective interaction between the zirconium-based nanoparticles and the siliceous nanodomains that induces changes in the hybrids' emission features. Planar waveguides were obtained by spin-coating of the prepared sols on sodalime and silica substrates. Refractive index, thickness, number of propagating modes, and attenuation coefficient were measured at 543.5, 632.8 and 1550 nm by the prism coupling technique. The synergism between the two hybrid precursors resulted in monomode planar waveguides with low losses in the infrared ( from 0.6-1.1 dB cm(-1)) which also support a number of propagating modes in the visible ( losses from 0.4-1.5 dB cm(-1)). Channel waveguides were also obtained by UV photopatterning using amplitude or phase masks and propagating modes were observed at 1550 nm.

Variable influence of ferric and cupric ions on Saccharomyces cerevisiae strains used in asymmetric organic synthesis.

Fe (III) and Cu (II) each at 50 mu M in four commercial strains of Saccharomyces cerevisiae induced an increase of NAD(P)(+) reduction in one strain (Turkish), but two others (Chilean and Brazilian), the presence of Fe(III) and/or Cu(II) diminished NAD(P)(+) reduction presumably due to free radicals formation inside these living cells. Suprisingly, in the American strain, Fe(III) induced a decrease and Cu (II) an increase of NAD(P)(+) reduction.