Search

Physalis peruviana L. is a species of commercial interest belonging to the Solanaceae family, cultivated preferentially in shaded environment, which still has cultivation restricted to small areas in Brazil and therefore requires further studies. Plants are directly affected by environmental factors such as drought, temperature, radiation, among others. These factors affect not only the vegetative organs, but also reproductive structures, which may cause damage to agronomically explored plants. With the need for shading presented by the crop, the present work aimed to characterize the pollen grain and to verify the influence of shade nets used in shading on the morphology of pollen grains of this species. The work was developed at the Lavras Federal University, where three replications of two plants were cultivated under full sun and under shadenets white, blue, red and black. Flower anthesis pollen was collected, processed and photographed by scanning electron microscope (SEM). Polar diameter, equatorial diameter and pollen area were measured in ten pollen grains. The results showed that P. peruviana pollen grains are isopolar, radial, prolato-spheroidal in shape and medium in size. There was also an increase in pollen grain area when cultivated in shading with white shade net and in full sun. [ABSTRACT FROM AUTHOR]

The batteries convert chemical energy into electrical energy and are responsible for the operation of laptops, watches, telephones, calculators, radios and cardiac pacemakers. Alkaline cells, which are known in the art as having an inorganic base, are composed of a porous zinc anode immersed in an alkaline solution of potassium hydroxide or sodium hydroxide, and of a cathode of compacted manganese dioxide. The objective of this study was to perform physical-chemical analyzes (pH, conductivity, real color and turbidity) in three different types of batteries (alkaline and two zinc manganese) and to identify the presence of certain metals such as cadmium, lead, iron, manganese, zinc and potassium through a leaching test. The composition of the cells was also quantified and qualified by means of instrumental analyzes using X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM) technique. The values found were compared with the current legislation (CONAMA, Resolution 401/2008, resolution 430/2011) where it was found that the pH, turbidity, real color, iron, manganese and zinc parameters exceeded the legal limits while the values of metals cadmium and lead have met the limits proposed by the legislation. In this way, it is fundamental that there is awareness of the society and monitoring of the responsible bodies regarding the correct disposal of the batteries, avoiding future problems, since the same ones in contact with a water course, can entail in complications to the environment. [ABSTRACT FROM AUTHOR]

Scanning electron microscopy (SEM) coupled with X-ray dispersive energy spectroscopy (EDS) has as its operating principle the use of a small diameter electron beam to explore the surface of the sample under study and identify chemical elements present in the samples. Butterflies are potential bioindicators of environmental quality, being possible to observe in some species the migration process, and thus, they unintentionally become victims of metal dispersion. The present study aimed to identify and perform a semiquantitative analysis of the presence of heavy metals in wings of the species Hamadryas februa. The specimens were collected on the campus of the University of Vale do Paraíba (UNIVAP), São José dos Campos, SP, in three distinct locations: butterfly garden; inside a fragment of Atlantic Forest and surrounding the Center for Planning and Development of Education (CEPLADE). A total of five butterfly specimens were selected for removal of a fragment of the lower wing, and the specimens were immediately released. The fragments were fixed in a sample holder, following the drying process, treatment with gold metallization, and analysis under a Scanning Electron Microscope. Semiquantitative analyses were performed based on the total atomic percentage of the metals found in each sample: iron (0.28%), manganese (0.74%), nickel (0.77%), cobalt (2.32%), copper (4.96%), zinc (11.71%), bromine (12.83%), aluminum (19.57%), lead (21.79%) and mercury (24.98%). According to the analyses, the samples showed marked concentrations of lead and mercury. This work may indicate that butterflies from the species Hamadryas februa are able to accumulate heavy metals in their scales. [ABSTRACT FROM AUTHOR]

The energy that a material absorbs during its fracture is a very important parameter in the steels. In most parts of the applications in the Market, it is searched a kind of steel that can be resistant and in the same time can have tenacity so in that way, they can be able to avoid catastrophic and fragile failures. On this way, the heat treatment of hardening and tempering is one of the alternatives to be applied for changing the mechanical properties of a big variety of steels. Like this, it is very important that the influences of different conditions of heat treatment that are applied in the same alloy be studied, evaluating the mechanical and microstructural properties which were obtained after the heat treatment. This article has the aim to evaluate the behavior of tenacity of SAE 8640 steel, for that, fifteen pieces of tests were made, they were submitted to the same hardening process and separated in three categories of tempering process (200°C, 400°C e 600°C). It was performed metallographic analysis to get the images of the microstructure as stereomicroscope and electron microscope scanning to get the images of fractured surface together with a hardness test and rehearsal Charpy respecting the ASTM E-23 standard, after the analysis, it was possible to conclude that the material which was submitted to 600°C heat treatment had its hardness decreased and its tenacity increased together with a more ductile behavior than when it was submitted to the materials to200°C e 400°C which kept similar characteristics. [ABSTRACT FROM AUTHOR]

Ferritic stainless steel has good electrical conductivity and corrosion resistance, enabling its use as an interconnector for low temperature fuel cells. The performance of these electrodes is related to the surface porosity, which can be obtained through the anodizing process. However, the stainless steel anodizing process has been mainly done for coloring ferritic stainless steel with pulsed current application. Thus, the objective of this work deals with the anodizing of ferritic stainless steel to obtain a porous surface through the application of direct current. For this purpose, anodization was performed in INCO electrolyte (2.5 M CrO3 + 5 M H2SO4) with time variation. Scanning electron microscope (SEM) analyzes showed the formation of a porous surface, and the anodizing time does not seem to have influenced the process. Electrochemical analysis showed that the anodizing time may have favored the formation of barrier oxide. However, the dissolution process that occurs during anodizing may have been more intense than the oxide formation, causing similar electrical conductivity measurements between samples without and with anodizing. In this case, it is possible to obtain a porous and conductive surface by anodizing INCO electrolyte with the application of direct current. [ABSTRACT FROM AUTHOR]

The use of automotive catalysts has been increasing in recent decades. With the strict regulations governing the emission of polluting gases, the number of catalysts that are discarded also grows, generating enormous volume of waste, which can be a source for urban mining. The objective of this work is to characterize deactivated automotive catalysts in terms of mineralogical, structural and elemental composition, quantitatively and qualitatively. The analyzes were performed in granulometry by laser diffraction, X-ray diffractometer (XRD), scanning electron microscope with X-ray energy dispersion spectroscopy (SEM / EDS), Raman spectroscopy and inductive coupling plasma optical spectrometry (ICP-OES). The studied automotive catalyst presented cracks and contaminants such as P, Ca, F, C and S, accentuating the deactivation process. The largest composition identified was cordierite, corresponding to 40.17%. The catalysts of the platinum group identified in the automotive catalyst were, Pd (0.92%), Pt (0.03%) and Rh (0.17%). [ABSTRACT FROM AUTHOR]

Due to the complexity of itabirite ores, their characterization is required, with emphasis on microstructure. Widely used is the scanning electron microscope (SEM) with the chemical energy-dispersive microanalyzer (EDS). An efficient computerized analytical system is MLA (Mineral Liberation Analyzer) which uses backscattered electrons images (BSE) and X-ray spectra (EDS) to identify the minerals in polished sections of ore particles. Thus, microstructural composition maps are generated, with very important information such as liberation, mineral associations and modal analysis. There is excellent statistical significance because several thousand particles are analyzed. Four samples of iron ores from the Iron Quadrangle, Minas Gerais, with different degrees of microstructural complexity have been studied. The particle sizes (-0.500 +0.300 mm and -0.300 +0.212 mm) were analyzed by X-ray diffraction, Mossbauer spectroscopy and MLA. By the instrumental methods, abundant minerals were quartz and hematite, obviously; also identified were goethite, and minor gibbsite and magnetite. In general, these data were consistent with MLA's. Some minor inconsistences between the global chemical analyses and the quantitative microstructure data are due to the different localized analytical sampling and the degree of homogenization. Quartz liberation was above 90% in three samples; the exception was the APV4 sample with only 60% quartz liberation, where quartz is associated with hematite (mainly) and goethite. [ABSTRACT FROM AUTHOR]