Centro de Tecnologia Mineral

In the present work the morphology of natural fibers was correlated with their mechanical properties via image analysis. Jute, sisal, curaua, coir and piassava fibers were tested under direct tension in a universal testing machine and the cross-sectional areas of the fibers were calculated using images obtained in a scanning electron microscopy. For the jute fiber the tests were performed for several gage lengths in order to investigate its influence on the tensile strength and to compute the machine compliance. For sisal, jute and curaua fibers the amount of fiber-cells, the size of the cell walls and the real area of the fibers were measured and their correlation with the tensile strength addressed. The curaua fiber presented the highest mechanical performance with tensile strength and Young's modulus of 543 MPa and 63.7 GPa, respectively. Weibull statistical analysis was used to quantify the variability of fiber strength. The sisal fibers presented the highest Weibull modulus (3.70), whereas the curaua presented the lowest one (m = 2.2), which means that the sisal had the lowest variability and curaua the highest.

An intercomparison of aerosol backscatter lidar algorithms was performed in 2001 within the framework of the European Aerosol Research Lidar Network to Establish an Aerosol Climatology (EARLINET). The objective of this research was to test the correctness of the algorithms and the influence of the lidar ratio used by the various lidar teams involved in the EARLINET for calculation of backscatter-coefficient profiles from the lidar signals. The exercise consisted of processing synthetic lidar signals of various degrees of difficulty. One of these profiles contained height-dependent lidar ratios to test the vertical influence of those profiles on the various retrieval algorithms. Furthermore, a realistic incomplete overlap of laser beam and receiver field of view was introduced to remind the teams to take great care in the nearest range to the lidar. The intercomparison was performed in three stages with increasing knowledge on the input parameters. First, only the lidar signals were distributed; this is the most realistic stage. Afterward the lidar ratio profiles and the reference values at calibration height were provided. The unknown height-dependent lidar ratio had the largest influence on the retrieval, whereas the unknown reference value was of minor importance. These results show the necessity of making additional independent measurements, which can provide us with a suitable approximation of the lidar ratio. The final stage proves in general, that the data evaluation schemes of the different groups of lidar systems work well.

Abstract. >We analyse simulations performed for the Chemistry-Climate Model Initiative (CCMI) to estimate the return dates of the stratospheric ozone layer from depletion caused by anthropogenic stratospheric chlorine and bromine. We consider a total of 155 simulations from 20 models, including a range of sensitivity studies which examine the impact of climate change on ozone recovery. For the control simulations (unconstrained by nudging towards analysed meteorology) there is a large spread (±20 DU in the global average) in the predictions of the absolute ozone column. Therefore, the model results need to be adjusted for biases against historical data. Also, the interannual variability in the model results need to be smoothed in order to provide a reasonably narrow estimate of the range of ozone return dates. Consistent with previous studies, but here for a Representative Concentration Pathway (RCP) of 6.0, these new CCMI simulations project that global total column ozone will return to 1980 values in 2049 (with a 1σ uncertainty of 2043–2055). At Southern Hemisphere mid-latitudes column ozone is projected to return to 1980 values in 2045 (2039–2050), and at Northern Hemisphere mid-latitudes in 2032 (2020–2044). In the polar regions, the return dates are 2060 (2055–2066) in the Antarctic in October and 2034 (2025–2043) in the Arctic in March. The earlier return dates in the Northern Hemisphere reflect the larger sensitivity to dynamical changes. Our estimates of return dates are later than those presented in the 2014 Ozone Assessment by approximately 5–17 years, depending on the region, with the previous best estimates often falling outside of our uncertainty range. In the tropics only around half the models predict a return of ozone to 1980 values, around 2040, while the other half do not reach the 1980 value. All models show a negative trend in tropical total column ozone towards the end of the 21st century. The CCMI models generally agree in their simulation of the time evolution of stratospheric chlorine and bromine, which are the main drivers of ozone loss and recovery. However, there are a few outliers which show that the multi-model mean results for ozone recovery are not as tightly constrained as possible. Throughout the stratosphere the spread of ozone return dates to 1980 values between models tends to correlate with the spread of the return of inorganic chlorine to 1980 values. In the upper stratosphere, greenhouse gas-induced cooling speeds up the return by about 10–20 years. In the lower stratosphere, and for the column, there is a more direct link in the timing of the return dates of ozone and chlorine, especially for the large Antarctic depletion. Comparisons of total column ozone between the models is affected by different predictions of the evolution of tropospheric ozone within the same scenario, presumably due to differing treatment of tropospheric chemistry. Therefore, for many scenarios, clear conclusions can only be drawn for stratospheric ozone columns rather than the total column. As noted by previous studies, the timing of ozone recovery is affected by the evolution of N2O and CH4. However, quantifying the effect in the simulations analysed here is limited by the few realisations available for these experiments compared to internal model variability. The large increase in N2O given in RCP 6.0 extends the ozone return globally by ∼ 15 years relative to N2O fixed at 1960 abundances, mainly because it allows tropical column ozone to be depleted. The effect in extratropical latitudes is much smaller. The large increase in CH4 given in the RCP 8.5 scenario compared to RCP 6.0 also lengthens ozone return by ∼ 15 years, again mainly through its impact in the tropics. Overall, our estimates of ozone return dates are uncertain due to both uncertainties in future scenarios, in particular those of greenhouse gases, and uncertainties in models. The scenario uncertainty is small in the short term but increases with time, and becomes large by the end of the century. There are still some model–model differences related to well-known processes which affect ozone recovery. Efforts need to continue to ensure that models used for assessment purposes accurately represent stratospheric chemistry and the prescribed scenarios of ozone-depleting substances, and only those models are used to calculate return dates. For future assessments of single forcing or combined effects of CO2, CH4, and N2O on the stratospheric column ozone return dates, this work suggests that it is more important to have multi-member (at least three) ensembles for each scenario from every established participating model, rather than a large number of individual models.

This paper describes the construction and main components of a full-scale superconducting magnetic levitation vehicle. The prototype, comprising four 1.5-m-long wagons, will travel a short test line of 200 meters, connecting two buildings inside the campus of the Federal University of Rio de Janeiro. The efforts to implement this technology started thirteen years ago with a small-scale prototype in an attempt to prove the concept. The second step was the construction of a functional prototype that could levitate more than one Ton. The actual stage of this project is the construction of an operational prototype mentioned above, designed to transport up to 24 passengers. This work has been reported in several previous editions of the ASC conference. New details about the elevated test line, the permanent magnetic (Nd-Fe-B) guideways, the cryostats with YBCO high critical temperature superconductors, the energy conditioning, the linear induction motor and its regenerative braking, as well as the automatic supply system of liquid nitrogen will be presented in the proposed paper. Tests with this operational prototype demonstrate the technology feasibility.

Workplace spirituality is a renowned topic now-a-days and is gaining gratitude and value among academicians and industrial people. Workplace spirituality (WPS) aims at meaningful work, sense of community, and value of organization. The purpose of the present study is to examine the relationship between workplace spirituality dimensions and work satisfaction by taking trust as a mediator. Using convenience sampling, a five-point Likert scale questionnaire is used to get data from teachers working in the education sector. Two hundred questionnaires were rotated in universities and 174 responses were generated. Multiple regression is used to test the hypotheses of the study using Barron and Kenny's method. The results showed that WPS has a significantly positive relationship with trust and trust significantly mediates the impact of workplace spirituality on job satisfaction. In future, new dimensions should be added to workplace spirituality. New moderators should be checked along with the mediator. Creativity in the form of improved communication among the teachers can be generated with the help of the promotion of workplace spirituality. The findings indicated that there is a positive relationship between WPS and job satisfaction and trust between employees would mediate the interaction of WPS and job satisfaction as the p-values are less than .05.

This study characterizes the precursor mineralogy and geochemistry of the Neoproterozoic iron ore deposits as well as some associated Na-containing manganese assemblages of the Urucum district, Mato Grosso do Sul, Brazil. It is based on ten mineralogically well characterized samples (six of banded iron-formation (BIF), three of manganese formations, and a sample of a veinlet that crosscuts the manganese assemblage), which were carefully selected so as avoid as much as possible supergene enrichment and secondary alteration (weathering), both of which are pervasive in the Urucum district. The six BIF samples are representative of the extensive Urucum BIF sequence from which the rich iron ores were developed by supergene enrichment and are considered to be precursors to the iron ore. The manganese-rich samples are part of unusual siliceous manganese horizons that contain complex silicate assemblages with braunite, cryptomelane, some pyrolusite, and authigenic aegirine. The Urucum BIF sequence is distinctive because it consists almost entirely of hematite and chert (jasper) with almost all of the iron present as only Fe2O3. This is in sharp contrast to the iron chemistry of much older (Archean and Early Proterozoic) BIF, in which a very large proportion of the iron occurs as ferrous iron in magnetite, carbonates, and silicates. As such, the Urucum BIF are essentially identical to those of the Neoproterozoic Rapitan sequence (755–730 Ma) of the Yukon and Northwest Territories of Canada. The Urucum sequence contains abundant dropstones, whereas the Rapitan sequence is set among diamictites but also contains dropstones. The δ 13C values of carbonates at Urucum are low, ranging from –5.2 to –7.0 per mil, which reflects their deposition in a glaciomarine setting. The REE concentrations of the BIF, as well as three Mn formation samples, are very similar and are almost completely lacking positive Eu anomalies (relative to NASC). This is in sharp contrast to the pronounced positive Eu anomalies of Archean and Early Proterozoic iron-formations. The general trend of the REE profiles (in NASC plots), with some enrichment of the heavy REE, is qualitatively very similar to that of modern seawater. The source of the Fe, Mn, and Si is concluded to be from typical ocean water with some deep-sea hydrothermal component. The reappearance of the Neoproterozoic Urucum sequence with BIF and interlayered manganese formations, together with the Rapitan sequence of similar Neoproterozoic age, after an absence of such sedimentary sequences in the geologic record for about 1.1 billion years, is considered to reflect ocean stagnation (with anoxic conditions), which may have been caused by a near-global ice cover, referred to as snowball Earth.

Biosorption processes emerge as an economical and eco-friendly alternative technology for the removal of pollutants present in the environment. One biosorption process application is found in the immobilization of microbial cells for the removal of toxic pollutants in industrial wastewater. The immobilization of microorganisms on magnetic nano-based carriers is a relevant new technique applied to obtain biocatalysts for environmental pollution control, however, it has been little described in the literature. Magnetic nanoparticles present several advantages when compared to suspended microorganism technology and conventional methods of cell immobilization, such as simple recovery of catalysts from the liquid phase. Considering the relevant application of magnetic nanoparticles as a support for microorganism immobilization, this review aims to present potential studies in the immobilization of bacteria, yeast, and fungi on magnetic nano-based carriers. Immobilization carriers and methods are highlighted and discussed based on their strengths and drawbacks. Isotherm and kinetic models are presented. This review also highlights the application of immobilized microbial nanoparticles in the removal of heavy metals from the environment. The state-of-the art of biosorption technology applying magnetically immobilized cells is presented in this review and provides insights into this research area.

BACKGROUND: Silicone gel dressings decrease scar volume and soften hypertrophic tissue, allowing it to be more easily controlled by other methods. Although silicone does not appear to be an essential component of the treatment, nonsilicone dressings have been reported to cause no change in physical parameters during a 2-month treatment period. OBJECTIVE: To compare silicone and nonsilicone gel dressings in the treatment of keloids and hypertrophic scars, including a control group, and to evaluate the effectiveness of these treatments using two new assessment techniques. METHODS: Patients were randomly chosen to receive silicone or nonsilicone gel dressings in a 4.5-month controlled prospective study. Scar size, induration, and symptoms were evaluated before and after the treatment. Scar color was visually measured using a color palette catalog, and a new device was developed to measure intracicatricial pressure. RESULTS: All of the measured parameters were significantly reduced in both silicone- and nonsilicone-treated groups, as compared to the control, with no significant differences between them. CONCLUSION: Silicone and nonsilicone gel dressings are equally effective in the treatment of keloids and hypertrophic scars.

Neuromodulation of deep brain structures (deep brain stimulation) is the current surgical procedure for treatment of Parkinson's disease (PD). Less studied is the stimulation of cortical motor areas to treat PD symptoms, although also known to alleviate motor disturbances in PD. We were able to show that optogenetic activation of secondary (M2) motor cortex improves motor functions in dopamine-depleted male mice. The stimulated M2 cortex harbors glutamatergic pyramidal neurons that project to subcortical structures, critically involved in motor control, and makes synaptic contacts with dopaminergic neurons. Strikingly, optogenetic activation of M2 neurons or axons into the dorsomedial striatum increases striatal levels of dopamine and evokes locomotor activity. We found that dopamine neurotransmission sensitizes the locomotor behavior elicited by activation of M2 neurons. Furthermore, combination of intranigral infusion of glutamatergic antagonists and circuit specific optogenetic stimulation revealed that behavioral response depended on the activity of M2 neurons projecting to SNc. Interestingly, repeated M2 stimulation combined with l -DOPA treatment produced an unanticipated improvement in working memory performance, which was absent in control mice under l -DOPA treatment only. Therefore, the M2-basal ganglia circuit is critical for the assembly of the motor and cognitive function, and this study demonstrates a therapeutic mechanism for cortical stimulation in PD that involves recruitment of long-range glutamatergic projection neurons. SIGNIFICANCE STATEMENT Some patients with Parkinson's disease are offered treatment through surgery, which consists of delivering electrical current to regions deep within the brain. This study shows that stimulation of an area located on the brain surface, known as the secondary motor cortex, can also reverse movement disorders in mice. Authors have used a brain stimulation technique called optogenetics, which allowed targeting a specific type of surface neuron that communicates with the deep part of the brain involved in movement control. The study also shows that a combination of this stimulation with drug treatment might be useful to treat memory impairment, a kind of cognitive problem in Parkinson's disease.

ZAM is an env-containing member of the gypsy family of retrotransposons that represents a possible retrovirus of invertebrates. In this paper, we traced ZAM mobilization to get information about a potential path a retroelement may take to reach the germ line of its host. In situ hybridization on whole-mount tissues and immunocytochemistry analyses with antibodies raised against ZAM Gag and Env proteins have shown that all components necessary to assemble ZAM viral particles, i.e., ZAM full-length RNAs and Gag and Env polypeptides, are coexpressed in a small set of follicle cells surrounding the oocyte. By electron microscopy, we have shown that ZAM viral particles are indeed detected in this somatic lineage of cells, which they leave and enter the closely apposed oocyte. Our data provide evidence that the vesicular traffic and yolk granules in the process of vitellogenesis play an important role in ZAM transfer to the oocyte. Our data support the possibility that vitellogenin transfer to the oocyte may help a retroelement pass to the germ line with no need of its envelope product.

Lignocellulolytic enzymes have been extensively studied due to their potential for industrial applications such as food, textile, pharmaceutical, paper, and, more recently, energy. The influence of metal ions, chemical agents, and organic compounds on these enzyme activities are addressed in this chapter, based on data available in the scientific literature.

Sewage sludge (SS) has been widely used as organic fertilizer. However, its continuous use can cause imbalances in soil fertility as well as soil-water-plant system contamination. The study aimed to evaluate possible improvements in the chemical and microbiological characteristics of domestic SS, with low heavy metal contents and pathogens, through the composting process. Two composting piles were set up, based on an initial C/N ratio of 30:1, with successive layers of tree pruning waste and SS. The aeration of piles was performed by mechanical turnover when the temperature rose above 65 ºC. The piles were irrigated when the water content was less than 50 %. Composting was conducted for 120 days. Temperature, moisture content, pH, electrical conductivity (EC), carbon and nitrogen contents, and fecal coliforms were monitored during the composting. A reduction of 58 % in the EC of the compost (SSC) compared with SS was observed and the pH reduced from 7.8 to 6.6. There was an increase in the value of cation exchange capacity/carbon content (CEC/C) and carbon content. Total nitrogen remained constant and N-NO3- + N-NH4+ were immobilised in organic forms. The C/N ratio decreased from 25:1 to 12:1. Temperatures above 55 ºC were observed for 20 days. After 60 days of composting, fecal coliforms were reduced from 107 Most Probable Number per gram of total solids (MPN g−1) to 104 MPN g−1. I one pile the 103 MPN g−1 reached after 90 days in one pile; in another, there was recontamination from 105 to 106 MPN g−1. In SSC, helminth eggs were eliminated, making application sustainable for agriculture purposes.

• Saccharomyces cerevisiae showed 76% Cu(II) removal efficiency. • The biosorption process was adjusted to the Langmuir isotherm. • The yeast presented maximum biosorption capacity of 4.73 mg g −1 . • The analyzed variables influence the biosorption process. With the industrial and population advances, the generation of effluents containing heavy metals has grown a lot. In this work, the commercial biomass of the yeast Saccharomyces cerevisiae Perlage ® BB were carried out as Cu (II) ion biosorbent. The influence of some variables such as metal concentration, pH range, equilibrium time and biomass concentration were evaluated. The biosorption capacity was measured by adsorption isotherms, with the Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) models. The characterization of the biomass surface were investigated by Dispersive Energy X-Ray Fluorescence Spectrometry (EDX) and Atomic Force Microscopy (AFM). The results showed that the biomass presented good biosorption efficiency. The best fit of the data was obtained with the Langmuir model, detecting the maximum biosorption capacity of 4.73 mg g −1 . By the methods used in the characterization of the biomass surface, it was possible to verify the presence of the Cu (II) ion in the yeast.

Sediment has been considered to be one of the most important mercury methylation sites, but recent studies have demonstrated a new site that is relevant, i.e. the roots of floating aquatic macrophytes, where high methylation is observed. The effects of temperature, pH and electric conductivity on net mercury methylation were studied in the roots of the water-hyacinth Eichhornia crassipes of a freshwater coastal lagoon (Lagoinha, RJ, Brazil). Root samples were incubated, over three days, with 203HgCl2 addition, at different temperatures (10–90 °C), pH values (3–8) and different electrolytic solutions (KClO4, KCl and CaCl2, at 1, 5, 10, 25 and 50 mM, ranging between 18 and 760 µS cm−1). 203Hg-labeled methylmercury (Me203Hg) was extracted in toluene, after acid leaching, and measured by β-counting. Up to 35% of mercury added was converted to MeHg Methylation increased from 10 to 35 °C, and decreased thereafter. The process was completely inhibited at 90 °C. At pH values of 6 and 7 methylation was stimulated and a significant decrease was verified at pH 8. Increasing KClO4 concentrations led to a significant decrease in the methylation rates, while for KCl and CaCl2 solutions only a slight decrease was observed. Copyright © 1999 John Wiley & Sons, Ltd.

Mica-based pearlescent pigments are widely applied in plastics, cosmetics, automobiles coatings among others, but they seem to be not explored by the ceramic industry. In this work, the potential of two commercial special effect pigments (with gold and silver lustre, respectively) in the decoration of ceramic tiles was appraised by testing them dispersed into several ceramic coatings fired in a wide range of temperatures (700–1150 °C). The pigments were characterized by XRD, FTIR, SEM, XRF and PSD, while their technological behavior was assessed by determining phase composition (XRD) and colorimetric parameters (DRS) of ceramic materials, including a Pearlescence Index. Results indicate that mica titania pigments are stable in glassy coatings up to 900 °C, any deterioration of their optical properties being due to anatase-to-rutile and muscovite-to-feldspar transformations occurring at higher temperatures or after long firing times. The pigment type with a gold shine is particularly suitable for third fire decoration of ceramic tiles, involving low temperatures and fast firing schedules, where it can replace expensive precious metals lustres. Moreover, a certain satin effect was appreciable in porcelain stoneware tiles, unexpectedly persistent after firing at 1200 °C.

Oxygenation is an important parameter involved in the design and operation of mixing-sparging bioreactors and it can be analyzed by means of the oxygen mass transfer coefficient (k(L)a). The operational conditions of a stirred, submerged aerated 2-L bioreactor have been optimized by studying the influence of a second liquid phase with higher oxygen affinity (perfluorodecalin or olive oil) in the k(L)a. Using k(L)a measurements, the influence of the following parameters on the oxygen transfer rate was evaluated: the volume of working medium, the type of impellers and their position, the organic phase concentration, the aqueous phase composition, and the concentration of inactive biomass. This study shows that the best experimental conditions were achieved with a perfluorodecalin volume fraction of 0.20, mixing using two Rushton turbines with six vertical blades and in the presence of YPD medium as the aqueous phase, with a k(L)a value of 64.6 h(-1). The addition of 20% of perfluorodecalin in these conditions provided a k(L)a enhancement of 25% when pure water was the aqueous phase and a 230% enhancement when YPD medium was used in comparison to their respective controls (no perfluorodecalin). Furthermore it is shown that the presence of olive oil as a second liquid phase is not beneficial to the oxygen transfer rate enhancement, leading to a decrease in the k(L)a values for all the concentrations studied. It was also observed that the magnitude of the enhancement of the k(L)a values by perfluorodecalin depends on the biomass concentration present.

ABSTRACT We have developed an adaptive double-focusing method that is specifically designed for the field-data application of source-receiver Marchenko redatuming. Typically, the single-focusing Marchenko method is combined with a multidimensional deconvolution (MDD) to achieve redatuming. Our method replaces the MDD step by a second focusing step that naturally complements the single-focusing Marchenko method. Instead of performing the MDD method with the directionally decomposed Green’s functions that result from single-focusing, we now use the retrieved upgoing Green’s function and the retrieved downgoing focusing function to obtain a redatumed reflection response in the physical medium. Consequently, we only remove the strongest overburden effects instead of removing all of the overburden effects. However, the gain is a robust method that is less sensitive to imperfections in the data and a sparse acquisition geometry than the MDD method. In addition, it is computationally much cheaper, more straightforward to implement, and it can be parallelized over pairs of focal points, which makes it suitable for application to large data volumes. We evaluate the successful application of our method to 2D field data of the Santos Basin.

In the aluminum industry, the initial operation comprises the production of its oxide, Al2O3 (alumina) from ores, mainly the bauxite. The Bayer process is, in practice, the only used to produce alumina generating a huge amount of hazardous waste known as red mud. Among the proposed alternatives to consider red mud a useful by-product, the incorporation into clay ceramics allows large quantities to be reutilized as construction products. Several research works investigated this alternative but were limited to single clay incorporation without specific application in building construction products. In the present work the possibility of producing bricks and roofing tiles for building construction with plain red mud and incorporations separately, in two different clays, with low and high plasticity, was for the first time investigated. Both red mud and clays were characterized. Corresponding ceramics fired at 850, 950 and 1050°C were evaluated for their technological properties. The results indicated that plain red mud fired at any of these temperatures might be used as bricks according to the Brazilian standards. It could also be used for roofing tiles production when fired at 1050°C. Application in bricks for building construction and a preliminary environmental assessment were for the first time presented.

Filamentous fungi were resistant to high concentrations of imidazolium-based ionic liquids, and<italic>Pseudomonas aeruginosa</italic>was tolerant to [NTf₂] anions.

Approximately a decade ago, superconducting maglev train prototypes started to be developed. Researchers from China, Germany, and Brazil have built prototypes carrying people based on superconducting levitation technology. The Brazilian MagLev project, named MagLev-Cobra, started in 2000 with a small-scale prototype that was concluded in 2006. After that, efforts toward a full-scale test vehicle for 30 passengers began. This vehicle will be composed of 4 modules, each one 1.5 m long, with six levitation cryostats and a linear induction motor. The first module and 12 m of test track are already constructed and this paper will describe the following tests: air gap as a function of load, temporal air gap stability, linear motor traction force, and vehicle acceleration. The paper will also describe the construction details of module, linear motor, and the rail.