Removal of radionuclides from acid mine waters by retention on adsorbing materials

This study proposes a method for decontamination of acid drainage water from a uranium mine, as an alternative process to lime treatment. The research embodied the recovery of uranium with an ion-exchange resin, treatment of effluent resin with lime, or with inorganic adsorbents and biosorbents. The uranium decontamination level using the resin process was 94% and allowed the recovery of this element as a commercial product. Among the inorganic adsorbents studied, phosphogypsum was effective for Ra-226, Ra-228, and Pb-210 removal. Among the biosorbents, Sargassum sp.was superior in relation to its specific capacity to accumulate and remove Ra-226.

Brillouin scattering in planar waveguides. II. Experiments

Silica-titania planar waveguides of different thicknesses and compositions have been produced by radio-frequency sputtering and dip coating on silica substrates. Waveguides were also produced by silver exchange on a soda-lime silicate glass substrate. Brillouin scattering of the samples has been studied by coupling the exciting laser beam with a prism to different transverse-electric (TE) modes of the waveguides, and collecting the scattered light from the front surface. In multimode waveguides, the spectra depend on the m mode of excitation. For waveguides with a step index profile, two main peaks due to longitudinal phonons are present, apart from the case of the TE0 excitation, where a single peak is observed. The energy separation between the two peaks increases with the mode index. In graded-index waveguides, m-1 peaks of comparable intensities are observed. The spectra are reproduced very well by a model which considers the space distribution of the exciting field in the mode, a simple space dependence of the elasto-optic coefficients, through the value of the refraction index, and neglects the refraction of phonons. A single-fit parameter, i.e., the longitudinal sound velocity, is used to calculate as many spectra as is the number of modes in the waveguide. (C) 2003 American Institute of Physics.

Optimisation of conditions for the extraction of casearins from Casearia sylvestris using response surface methodology

Optimal conditions for the extraction of casearins from Casearia sylvestris were determined using response surface methodology. The maceration and sonication extraction techniques were performed using a 3 x 3 x 3 full factorial design including three acidity conditions, three solvents of different polarities and three extraction times. The yields and selectivities of the extraction of casearins were significantly influenced by acidity conditions. Taking into account all variables tested, the optimal conditions for maceration extraction were estimated to involve treatment with dichloromethane saturated with ammonium hydroxide for 26 h. Similar yields and selectivities for casearins were determined for sonication extraction using the same solvent but for the much shorter time of I h. The best results for stabilisation of the fresh plant material were obtained using leaves that had been oven dried at 40 degrees C for 48 h. Copyright (c) 2006 John Wiley & Sons, Ltd.

Aging behaviour of 25Cr-17Mn high nitrogen duplex stainless steel

The precipitation behaviour of a nickel free stainless steel containing 25% chromium, 17% manganese and 0.54% nitrogen, with duplex ferritic-austenitic microstructure, was studied using several complementary techniques of microstructural analysis after aging heat treatments between 600 and 1 000 degrees C for periods of lime between 15 and 6 000 min. During aging heat treatments, ferrite was decomposed into sigma phase and austenite by a eutectoid reaction, like in the Fe-Cr-Ni duplex stainless steel. Chromium nitride precipitation occurred in austenite, which had a high nitrogen supersaturation. Some peculiar aspects were observed in this austenite during its phase transformations. Chromium nitride precipitation occurred discontinuously in a lamellar morphology, such as pearlite in carbon steels. This kind of precipitation is not an ordinary observation in duplex stainless steels and the high levels of nitrogen in austenite can induce this type of precipitation, which has not been previously reported in duplex stainless steels. After chromium nitride precipitation in austenite, it was also observed sigma phase formation near the cells or colonies of discontinuously precipitated chromium nitride. Sigma phase formation was made possible by the depletion of nitrogen in those regions. Time-temperature-transformation (precipitation) diagrams were determined.

Peanut seed tegument is affected by liming and drying method

Calcium plays a fundamental role in cell division and growth, and is an important constituent of the cell wall. An increase in Ca concentration in the tegument of peanut (Arachis hypogea L.) seeds in response to lime application can affect its structure. The tegument structure can also be affected by the drying method of the seeds. The effects of lime application and drying methods as affecting the peanut seed tegument structure were studied in seeds from a field experiment conducted in Sao Manuel, São Paulo, Brazil. Peanut (cv. Botutatu, Valencia Type) was grown in presence or absence of 2.1 Mg ha(-1) of lime and dried in an oven, in shade and in the field. The tegument anatomical features were described and its structure was analysed. Pectic substances, lipidic reserves and starch accumulation were studied. The peanut tegument exhibited well differentiated exotesta, mesotesta and endotesta rich in pectates and covered by a cuticle. Tannin was not observed but there was lipid accumulation in mature teguments. Lignin was observed in the vascular bundles. Lime increased the tegument thickness and decreased the central cavity mainly in the exotesta cells when the period of seed drying was shortened. The effect of drying method upon the tegument was more noticeable in seeds grown without lime. It can be inferred that liming increased the resistance of the tegument.

Uso de indicadores para estimar fluxos de matéria seca ileal em eqüinos fistulados

This experiment was carried out with six half-bred Bretao-Campolinacolts with ileum fistulated to evaluate the difference in the ileum dry matter flow estimated by chromic oxide, cellulose, NDF, lignin and fecal lignin through the collection of ileum samples digesta at 28 h intervals, totalizing six samples per animal, starting at 10:00 a.m. The animals were fed ad libitum with the following diets: R1: clephantgrass, R2: elephantgrass plus ground corn, and R3: elephantgrass plus ground corn plus soybean meal. The data was statistically described, based on the coefficient of variation. The values of dry matter prececal digestion coefficients were, respectively, for diets 1, 2 and 3, at six schedules, for cellulose (-16.4; 21.4 and 6.6%), NDF(-34.7; 28.8 and -12.8%), to lignin (-51.5; -5.1 and -25.7%), in two schedules for cellulose (-13.4; 25.6 and 21.5%), fecal lignin (-37.1, 16.6 and -6.4%) and chromic oxide (-219.3, 36.4 and 9.5%). The coefficients of variation were, respectively, for the diets i, 2 and 3, at six schedules, for cellulose (148.3; 107.5 and 522.7%), NDF (95.4; 80.9 and 314.3%), lignin (210.2; 752.3 and 209.6%), at two schedules for cellulose(148.5; 80.7 and 70.0%), fecal lignin, (262.4; 177.9 and 723.5%) and chromic oxide (141.1; 158.9 and 473.4%). In diet i, the ileum dry matter now were over estimated for all markers, showing that chosen collection lime to estimate the flows were not adequate. Based on the coefficient of variation of the diets 2 and 3, the cellulose at two schedules was the most marker indicator to determine the ileum dry matter flow.

Root growth and cotton nutrition as affected by liming and soil compaction

Soil columns were produced by filling PVC tubes with a Dark Red Latosol (Acrortox, 22% of clay). A compacted layer was established at the depth of 15 cm in the columns. In the compacted layer, soil was packed to 1.13, 1.32, 1.48, and 1.82 Mg kg(-1), resulting in cone resistances of 0.18, 0.43, 1.20, and 2.50 MPa. Cotton was cropped for 30 days. Lime was applied to raise base saturation to 40, 52, and 67%. The highest base saturation caused a decrease in phosphorus (P) and zinc (Zn) concentrations in the plants. A decrease in root dry matter, length and surface area was also observed. This could be a consequence of lime induced Zn deficiency. Root growth was decreased in the compacted layer, and complete inhibition was noticed at 2.50 MPa. Once the roots got through the compacted layer, there was a growth recovery in the bottom layer of the pots. The increase in base saturation up 52% was effective in preventing a decrease in cotton root length at soil resistances to 1.20 MPa. Where the roots were shorter, there was an increase in nutrient uptake per unit of root surface area, which kept the plants well nourished, except for P.

Adsorptive potentiometric stripping analysis of trace tamoxifen at a glassy carbon electrode

A highly sensitive adsorptive stripping procedure for trace measurement of the anticancer drug tamoxifen is described. The method is based on controlled adsorptive accumulation of the drug at an electrochemically treated glassy carbon electrode, followed by chronopotentiometric measurement of the surface species. The chronopotentiometric operation effectively addresses the large background contribution inherent to the glassy carbon electrode to yield a detection limit of 4 x 10(-10) M after 4 min preconcentration. The adsorptive stripping response is evaluated with respect to electrode type and conditioning, accumulation potential and lime, stripping current, pH, drug concentration, potential interferences, and other variables. Applicability to urine samples is illustrated. (C) 1997 Elsevier B.V. B.V.

Efeito da calagem sobre a produção de matéria seca de três gramíneas forrageiras

A greenhouse investigation was carried out to study the effects of liming on the dry matter (DM) production of the grasses Brachiaria brizantha (Hoscht.) Stapf. cv. Marandu, Andropogon gayanus Kunth cv. Planaltina and Panicum maximum Jacq cv. Aruana, cultivated on a Dark-Red Latosol, medium texture. The liming levels were obtained through the addition of carbonates in a Ca:Mg ratio of 4:1, necessary to increase the degree of base saturation (V%) to the following values; 4% (control), 20%, 36%, 52%, 68% and 84%. During the experimental period (180 days), four cuts were done to determine the DM production. The results indicated that the DM production was increased (P<0,05) with the liming-levels increased to the three grasses. Panicum maximum cv. Aruana yielded the lower DM quantity, but it presented a better response to liming. The inverse was observed in relation to A. gayanus. The data allowed to conclude that the DM production increased by liming and when the V% level was lower than 50%, it will be increased to 70% for establishment.

Rhodamine B-containing silica films from TEOS precursor: Substrate surface effects detected by photoluminescence

This work presents the study of substrate surface effects on rhodamine B-containing silica films obtained from TEOS (tetraethylorthosilicate) acid hydrolysis. Soda-lime glass substrates were treated with basic solution under different reaction times and temperatures. Rhodamine B-containing silica films were deposited on pre-treated substrates by the spin-coating method. The substrate surface directly affects film morphology and homogeneity. The films are formed by packed silica spheres which protect the dye against acid-base attack. Luminescence spectra present shifts on the dye emission maximum as expected for different pH values on the substrate surface depending on the alkaline treatment. (c) 2006 Elsevier B.V. All rights reserved.

Thin films prepared from tungstate glass matrix

Vitreous samples containing high concentrations of WO3 (above 40% M) have been used as a target to prepare thin films. Such films were deposited using the electron beam evaporation method onto soda-lime glass substrates. These films were characterized by X-ray diffraction (XRD), perfilometry, X-ray energy dispersion spectroscopy (EDS), M-Lines and UV-vis absorption spectroscopy. In this work, experimental parameters were established to obtain stable thin films showing a chemical composition close to the glass precursor composition and with a high concentration of WO3. These amorphous thin films of about 4 mu m in thickness exhibit a deep blue coloration but they can be bleached by thermal treatment near the glass transition temperature. Such bleached films show several guided modes in the visible region and have a high refractive index. Controlled crystallization was realized and thus it was possible to obtain WO3 microcrystals in the amorphous phase. (C) 2007 Elsevier B.V. All rights reserved.

Crescimento radicular e aéreo de cultivares de arroz de terras altas em função da calagem

This work aimed to evaluate root growth, shoot development and nutrient absorption efficiency by rice cultivars Caiapo and Maravilha as affected by lime application. The experiment was carried out in a greenhouse, with treatments set up by Caiapo and Maravilha cultivars in combination with the base saturation (V%) of 10%, 40% and 70%. The experiment was in a randomized complete block design, with four replications. The number of tillers, root length, root dry matter, leaves and stems, leaf content and macronutrients absorption efficiency were evaluated. Comparing cultivars, Maravilha cultivar presented higher root dry weight, root length, number of stems, dry matter of stems and shoot than Caiapo cultivar, as well as accumulated more nutrients in the shoots. on the other hand, nutrient contents were higher in the cultivar Caiapo compared to Maravilha. Maravilha cultivar shows greater root and shoot growth while Caiapo shows higher nutrient absorption efficiency from the soil. The base saturation of 40% is the most effective for both cultivars.

Infestación natural de Lonchaeidae (Diptera) en variedades de melocotón

Se estudió la ocurrencia de Lonchaeidae en variedades de melocotón, conducidos sobre los patrones ‘Okinawa’ y Umê: Tropical, Ouromel 3, Jóia 4, Régis, Talismã, Aurora 2, Aurora 1, Dourado 2 y Doçura 2. Se colectaron muestras de 30 frutos por planta en el Banco de Germoplasma en Presidente Prudente, Brasil. Se obtuvieron 633 especímenes de Lonchaeidae; 394 de ellos en frutos de variedades sobre ‘Okinawa’ y 239 sobre Umê. Se capturaron especies como Neosilba zadolicha, N. inesperata, N. pendula, N. certa y Neosilba spp. (hembras). N. zadolicha y N. inesperata, se observaron en 77,78% de las muestras de las variedades sobre ‘Okinawa’. Sobre el patrón Umê la mayor incidencia fue de N. zadolicha , N. inesperata y N. pendula (55,6%, 33,3% y 33,3% respectivamente). Las variedades Ouromel 3, Talismã, Doçura 2 y Aurora 2 presentaron mayores infestaciones por Lonchaeidae. N. certa tuvo una menor incidencia y sólo se observó en la variedad Doçura 2 sobre ‘Okinawa’. Plantas con mayor número de frutos presentaron mayor incidencia de moscas por fruto; sin embargo, no hubo correlación entre peso del fruto y número de moscas. No se observó diferencia para peso del fruto y número de moscas por fruto entre los dos patrones, ‘Okinawa’ y Umê. Melocotones crecidos en los patrones ‘Okinawa’ y Umê en Presidente Prudente están infestados por especies de Lonchaeidae que presentan preferencia independientemente del peso de los frutos. El aporte de este trabajo al conocimiento de la comunidad de especies de Lonchaeidae ofrece una base para su control.

Qualidade física de um Latossolo Vermelho em recuperação há dezessete anos

The bulk density and resistance to penetration as indicators of recovery were studied with the objective to investigate the physical quality of a Red Latosol (Oxisol) under restoration for 17 years using green manures, soil correction, gypsum and pasture. The experimental design was a completely randomized with nine treatments and four replications. The treatments were: control (tilled soil without crop); Stizolobium aterrium; Cajanus cajan until 1994 and then substituted by Canavalia ensiformis; lime+S. aterrimum; lime+C. cajan until 1994 and then substituted by C. ensiformis; lime+gypsum+S. aterrimum; lime+ gypsum+C. cajan until 1994 and then substituted by C. ensiformis, the treatments were installed in 1992 and remained for seven years, in 1999 Brachiaria decumbens was planted; two other controls (native vegetation and exposed soil) were also used to compare. Bulk density, resistance to penetration and soil moisture were evaluated. The results were analyzed performing analysis of variance and Tukey test at probability of 5% to compare means. The treatments of reclamation are improving the physical qualities of soil and the results of treatment with C. cajan/C. ensiformis, lime and gypsum attained physical conditioning similar to soil under natural conditions.

Nanomechanical properties of glass-ceramic films obtained by pressure impregnation of oxide powders on commercial float glass surfaces

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)