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Here, we report the use of fluorescence spectroscopy for the identification of lubricant oils used in reciprocating compressors, and the use of silica gel as an adsorbent to capture lubricant oil vapors. The silica gel was tested for adsorption of lubricant oil vapors, by heating the samples at 200°C, the emission spectrum of the lubricant oils is observed on the silica gel layer, over 20 min of heating. The spectrum of the lubricant oils over the silica gel layer presents a redshift, an indication of the degradation effect. In order to investigate this effect on the optical properties, we conducted an experiment by heating the samples at (130 ± 4) °C, and collected at different times. The MID-infrared absorption of the samples presents bands of oxygen-containing groups at 1010 and 1050 cm-1, and NIR infrared absorption measurements at 3444 cm-1 show an increase in the hydroperoxide band during the degradation time. These two results indicate that the oxidation process is associated with the observed redshift of the absorption and emission bands in lubricant oils and over the adsorbent layer.

Juvenile Hormone (JH) is considered the main determinant of caste in social insects, though little is known about how this hormone acts in social wasps, especially the independent-founding species. The known relationship between JH titer and caste in the colony and we suggest a relationship among the effects of JH and the cuticular chemical profile. Therefore, this study aimed to test the hypothesis that topical application of JH to larvae of different instars alters the cuticular chemical composition of newly emerged females of Mischocyttarus consimilis (Zikán), influencing the dynamics of colony. Two techniques were used to evaluate the variation in cuticular chemical composition: Fourier transform infrared photoacoustic spectroscopy and gas chromatography coupled to mass spectrometry (GC-MS). Indeed, the application of JH did significantly alter the cuticular chemical composition of adult females that received treatment at the larval stage in comparison to control. The effects of JH were instar-dependent in that the results of topical application were significant when performed at third larval instar. Overall, these results add evidence that caste determination may, at least in part may be pre-imaginal in species of independent-founding social wasps.

The transesterification reaction is the most widely used process for biodiesel production. Monitoring it in real time enables optimization of the operational parameters, hence providing better yields and lowering the costs of biodiesel production. Techniques that have been used for this purpose include chromatography and spectroscopic methodologies. In this work, transesterification reactions were monitored on line, in situ, by fluorescence spectroscopy with ultraviolet excitation at ~360 nm. The temporal behavior of the fluorescence intensity was similar to that of the viscosity of the oil/alcohol/catalyst solution, as reported in the literature. The results indicated that UV-Vis fluorescence spectroscopy could be used on-line, in situ, for the efficient monitoring of biodiesel production, providing a valuable indication of the degree of success of the transesterification reaction. DOI: http://dx.doi.org/10.17807/orbital.v10i1.1026

In this work, we report the use of the fluorescence spectroscopy to identify lubricant oils. Optical characterization was performed in four commercial lubricant oils that are used in the reciprocating compressors. Mid-infrared absorption of samples indicates the presence of aromatic rings showing bands at 1605 cm-1 (C=C stretching) and 815 cm-1 (C–H stretch out of plane). UV-VIS absorption spectra show bands of di and polyaromatic rings (around 230 nm and 260 nm respectively). Exciting the samples at 360 nm, a broad emission band centred at 440 nm is observed, indicating that this excitation is appropriate to be used for the diagnosis of the oil presence in the environment.

Wasps can synthesize chemical compounds called venom whose function is to overcome prey and assist in defense of the colonies. Geographic Parameters such as sex, age, the season of the year, and diet determined the composition of the venom location, genetics, environment. However, studies on the compositional variability of venom are still limited due to the difficulty in obtaining samples and the complexity of these substances. This work describes the use of the Fourier Transform Infrared Photoacoustic Spectroscopy (FTIR-PAS) to investigate inter- and intraspecific variability in the venom chemical composition (VCC) of the social wasp Polybia paulista (Von Ihering 1896) and the ant Ectatomma brunneum (Smith 1858). The results reveal significant differences in VCC among the ant and wasp, even for samples obtained from the same environment. The genetic component, therefore, seemed to be the predominant factor determining the compounds present. The findings also showed that exogenous factors, such as diet, could also be responsible for intraspecific differences, especially in wasps. The FTIR-PAS technique proved to be a reliable way of assessing intra- and interspecific differences in social Hymenoptera VCC.

The transesterification reaction is the most widely used process for biodiesel production. Monitoring it in real time enables optimization of the operational parameters, hence providing better yields and lowering the costs of biodiesel production. Techniques that have been used for this purpose include chromatography and spectroscopic methodologies. In this work, transesterification reactions were monitored on line, in situ, by fluorescence spectroscopy with ultraviolet excitation at ~360 nm. The temporal behavior of the fluorescence intensity was similar to that of the viscosity of the oil/alcohol/catalyst solution, as reported in the literature. The results indicated that UV-Vis fluorescence spectroscopy could be used on-line, in situ, for the efficient monitoring of biodiesel production, providing a valuable indication of the degree of success of the transesterification reaction. DOI: http://dx.doi.org/10.17807/orbital.v10i1.1026

In this work, we report the use of fluorescence spectroscopy to identify lubricant oils. Optical characterization was performed in four commercial lubricant oils that are used in reciprocating compressors. Mid-infrared absorption of samples indicates the presence of aromatic rings showing bands at 1605 cm-1 (C=C stretching) and 815 cm-1 (C–H stretch out of plane). UV-VIS absorption spectra show bands of di- and polyaromatic rings (around 230 nm and 260 nm, respectively). By exciting the samples at 360 nm, a broad emission band centered at 440 nm is observed, indicating that this excitation is appropriate to be used for the diagnosis of oil presence in the environment. DOI: http://dx.doi.org/10.17807/orbital.v10i1.1032

The 1º Scientific Symposium about Natural Resources (1º Simpósio Científico sobre Recursos Naturais - SCRN) has as theme “Natural environmental and products: an interdisciplinary view”, and the main aim was encourage discussion among graduation and postgraduate students, and researchers with different disciplinary views, about the exploration, conservation and monitoring of natural resources, bringing out the importance of multidisciplinary actions in research to a responsible regional development. The event was a promotion of the Postgraduation Program in Natural Resource (Programa de Pós-graduação em Recursos Naturais - PGRN) of the State University of Mato Grosso do Sul (Universidade Estadual de Mato Grosso do Sul - UEMS) and received financial supported by Foundation for Support the Development of Teaching, Science and Technology of Mato Grosso do Sul (Fundação de Apoio ao Desenvolvimento do Ensino, Ciência e Tecnologia do Estado de Mato Grosso do Sul, Fundect). The event was organized in the following thematic scopes: 1) Applied materials development for natural resources; 2) Analytical methods and control for natural resources; 3) Valuation and characterization of natural environmental; 4) Environmental monitoring; 5) Natural products and derived from vegetal and animal origins; 6) Evaluation, systematic and chemistry ecology. In this special issue published in Orbital: The Electronic Journal of Chemistry the reader has a sample of the 250 works presented during four event days. To publish in this issue all participants were invited to submit a full paper following the journal Author Guidelines. Sandro Marcio Lima (UEMS) Chairman Claudia Andrea Lima Cardoso (UEMS) Guest Editor

This work presents the results of the investigation of structural and thermal properties of Nd3+-doped tellurite glasses with low OH content. The samples were characterized by XRD, FTIR, DTA, UV/VIS/NIR and Archimedes’ method. Tellurite glasses of composition (100 – x)(0.8TeO2 + 0.2WO3) + xNd2O3 (x = 0, 0.05, 0.5, 1, 2, and 4 mol%) were prepared in both ambient and oxygen atmospheres. All samples showed an increase of the values of Tg, Tx, and Tx-Tg with Nd2O3 addition. The reduction of OH content implies a slight decrease of Tg. The density and the molar volume of the glasses increased with Nd2O3. The intensity of the absorption bands associated with Te-O bonds of TeO4 units decreased compared with the bands associated with Te-O bonds of TeO3+1/3 units. This indicates that Nd2O3 favors the transformation of the TeO4 groups in TeO3 groups via TeO3+1, increasing the NBOs and contributing to the formation of strongly hydrogen-bonded OH groups. The samples made in O2 showed a reduction of 48% of “free” OH ions compared with the Amb ones.

Female wasps such as Polistes versicolor can form aggregates to face weather conditions that are not suitable to sustain their colonies. The interactions between individuals in these aggregates, just as in other associations, are probably facilitated by chemical signals. Of these compounds some of the most efficient during social interactions of insects are those called contact pheromones or superficial pheromones. This special type of pheromones, known as cuticular hydrocarbons, can be found in insects cuticle. They facilitate the differentiation of caste, species and nestmates, and may be important indicators of dominance as well as fertility. Some studies indicate that linear alkanes are important cuticular compounds for intraspecific recognition and discrimination. The aim of this study was to evaluate the relationship between reproductive physiologic condition and the linear alkanes present in the cuticle of females of P. versicolor in aggregates employing Gas Chromatography with Flame Ionization Detector (GC-FID). Females from distinct aggregates were differentiated by the chemical composition of their cuticle. In each aggregate, there was difference in cuticular chemical composition between females with different ovarian development degrees, allowing the distinction between inseminated and non-inseminated females.

A fundamental feature in the evolution of social insects is the separation of castes, and the presence of wide differentiation between castes indicates a more advanced degree of sociability. In this study, we evaluated factors that indicate the reproductive status of females in colonies of the social wasp Polistes versicolor. The reproductive status of each female was examined by measuring nine morphometric characters, by the cuticular chemical profile, insemination and by her relative age. We conclude that in P. versicolor colonies there are 3 female groups that show cuticular chemical profile difference. The first group belong to females with ovarioles filamentous, typical of workers; the second is females with ovarioles intermediates; and the third is a group of queens, which are older females, inseminated and with greater degree of ovarian development found among all females. On the other hand, there was no significant morphological differences between these female groups. Therefore, although no significant morphological differences among females there are other factors such as the cuticular chemical composition that is an indicative of reproductive physiological condition of female in the colony.

The synthesis of layered double hydroxides has been investigated aiming innumerous applications, mainly as adsorbent, catalyst and catalyst support materials, due their ability to adsorb anionic species and several aqueous soluble compounds. The carbonated magnesium-aluminium hydrotalcites are known as the main class of the layered double hydroxides and new composition are often characterized under the view point of thermal stability, crystallinity and catalytic performance for many reactions. Few trivalent cations are able to replace the aluminum one due the severe restriction for oxidation state and ionic radii, but the iron (III) one seems to be high potential to improve some of the characteristics required for that materials, such as specificity for built-rebuilt bonds in organic molecules. In this work, we have synthesized carbonated magnesium-aluminum hydrotalcite samples through the coprecipitation at pH 11 and investigate the Fe(III) insertion at 10 and 20 mol%. Thermal analysis, FTIR spectrometry and X-ray diffractometry techniques were used to understand the influence of the Fe(III) co-substitution, keeping the Mg(II) molar fraction invariable among the samples. We show the iron (III) insertion affects the dehydration and dehydroxylation processes due the changes in M-OH bond energies Very homogeneous structures were obtained for all of the samples dried at 100 ºC and a consistent lattice volume expansion was observed as a function of iron (III) content, which can be required for catalyst or catalyst matrix applications. DOI: http://dx.doi.org/10.17807/orbital.v10i1.1036

The synthesis of layered double hydroxides has been investigated aiming innumerous applications, mainly as adsorbent, catalyst and catalyst support materials, due their ability to adsorb anionic species and several aqueous soluble compounds. The carbonated magnesium-aluminium hydrotalcites are known as the main class of the layered double hydroxides and new composition are often characterized under the view point of thermal stability, crystallinity and catalytic performance for many reactions. Few trivalent cations are able to replace the aluminum one due the severe restriction for oxidation state and ionic radii, but the iron (III) one seems to be high potential to improve some of the characteristics required for that materials, such as specificity for built-rebuilt bonds in organic molecules. In this work, we have synthesized carbonated magnesium-aluminum hydrotalcite samples through the coprecipitation at pH 11 and investigate the Fe(III) insertion at 10 and 20 mol%. Thermal analysis, FTIR spectrometry and X-ray diffractometry techniques were used to understand the influence of the Fe(III) co-substitution, keeping the Mg(II) molar fraction invariable among the samples. We show the iron (III) insertion affects the dehydration and dehydroxylation processes due the changes in M-OH bond energies Very homogeneous structures were obtained for all of the samples dried at 100 ºC and a consistent lattice volume expansion was observed as a function of iron (III) content, which can be required for catalyst or catalyst matrix applications. DOI: http://dx.doi.org/10.17807/orbital.v10i1.1036