On the existence of ordered phases of encapsulated diamondoids into carbon nanotubes

We have investigated some diamondoids encapsulation into single walled carbon nanotubes (with diameters ranging from1.0 up to 2.2 nm) using fully atomistic molecular dynamics simulations. Diamondoids are the smallest hydrogen-terminated nanosized diamond-like molecules. Diamondois have been investigated for a large class of applications, ranging from oil industry to pharmaceuticals. Molecular ordered phases were observed for the encapsulation of adamantane, diamantane, and dihydroxy diamantanes. Chiral ordered phases, such as; double, triple, 4- and 5-stranded helices were also observed for those diamondoids. Our results also indicate that the modification of diamondoids through chemical functionalization with hydroxyl groups can lead to an enhancement of the molecular packing inside the carbon nanotubes in comparison to non-functionalized molecules. For larger diamondoids (such as, adamantane tetramers), we have not observed long-range ordering, but only a tendency of incomplete helical structural formation. © 2012 Materials Research Society.

Monitoramento da Integridade Estrutural de Sistemas Mecânicos via Observador de Estado Modal

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Milho alto óleo - parâmetros genéticos, correlações entre modelos fixo e misto e seleção

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Pseudomonas aeruginosa LBI production as an integrated process using the wastes from sunflower-oil refining as a substrate

Pseudomonas aeruginosa LBI produced surface active rhamnolipids when cultivated on waste from the sunflower-oil process under different conditions. These biosurfactants, which reduce the superficial and interfacial tensions between fluids, offer advantages over their chemical counterparts, especially because of their ecological acceptability. These molecules can be used in fields as diverse as chemical, pharmaceutical and petrochemical industries. In this work, we present the effect of C/N ratio on growth and production yield. The best production yields (Y-P/S) were achieved for C/N ratios (in g/g) of 8/1 (0.22) and 6.4/1 (0.23). The product concentration was very satisfactory (7.3 g/L) at C/N ratio of 8/1, especially when considering that the substrate was basically composed of wastes that would otherwise constitute an environmental disposal problem. (c) 2007 Elsevier Ltd. All rights reserved.

Genotoxicity and mutagenicity of Rosmarinus officinalis (Labiatae) essential oil in mammalian cells in vivo

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Yellow passion fruit seed oil (Passiflora edulis f. flavicarpa): physical and chemical characteristics

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

Vibration and oil analysis for monitoring problems related to water contamination in rolling

Trying to reduce particle contamination in lubrication systems, industries of the whole world spend millions of dollars each year on the improvement of filtration technology. In this context, by controlling fluid cleanliness, some companies are able to reduce failures rates up to 85 percent. However, in some industries and environments, water is a contaminant more frequently encountered than solid particles, and it is often seen as the primary cause of component failure. Only one percent of water in oil is enough to reduce life expectancy of a journal bearing by 80 percent. For rolling bearing elements, the situation is worse because water destroys the oil film and, under the extreme temperatures and pressures generated in the load zone of a rolling bearing element, free and emulsified water can result in instantaneous flash-vaporization giving origin to erosive wear. This work studies the effect of water as lubricant contaminant in ball bearings, which simulates a situation that could actually occur in real systems. In a designed bench test, three basic lubricants of different viscosities were contaminated with different contents of water. The results regarding oil and vibration analysis are presented for different bearing speeds.

Influence of organic and mineral soil fertilization on essential oil of Spilanthes oleracea cv. Jambuarana

In the present study, the composition of essential oil of leaves and inflorescences of jambu (Spilanthes oleracea. Jambuarana), under organic manuring and mineral fertilization, was stuhed. Jambu plants show important chemical properties and their production has been addressed for the extraction of the essential oils for cosmetics industries, due to their pharmacolopcal properties. The experimental area of treatments contained urea as mineral fertilizer (120 g m2), applied twice and organic fertilizer (8 kg m2), applied at the planting. Jambu leaves and flowers were harvested twice: the first at 90 days after seedling transplantation and at the opening of the flower buds. Branches were cut at 7 cm from the soil, thus new branches can bud for the accomplishment of the second crop which happened 40 days after the re-budhng. The essential oil was analyzed by gas chromatography coupled with mass-spectrometry. According to our results the most representative compounds were trans-caryophyllene, germacrene-D, 1-dodecene, spathulenol and spilanthol (a compound presenting anesthetic properties) occurring in inflorescences. Fertilization procedure does not affect the content and the quality of the essential oil in Jambu plants. © 2012 Academic Journals Inc.

Thermal behavior of coffee oil (Robusta and Arabica species)

Coffee seeds are a source for obtaining oil which is used in the candy, soluble coffee, and cosmetics industries. The main purpose of this study was the investigation of the lipid profile and thermal behavior of the roasted and in nature coffee oil of Arabica and Robusta species, using thermogravimetry, differential thermal analysis, derivative thermogravimetry, differential scanning calorimetry (DSC), and modulated DSC. Details concerning the thermal decomposition as well as data of the kinetic parameters have been described here. The kinetic studies were evaluated from several heating rates with a sample mass of 10 mg in open crucible under nitrogen atmospheres. The obtained data were evaluated with the isoconversional kinetic method, where the values of activation energy (Ea/kJ mol-1) were evaluated in function of the conversion degree (α). In addition, this oil was evaluated by modulated DSC from 25 to -60 °C, where the transition phase behavior was verified. © 2013 Akadémiai Kiadó, Budapest, Hungary.

Effect of Various Thickening Agents on the Rheological Properties of Oil-in-Water Emulsions Containing Nonionic Emulsifier

The knowledge of rheological characteristics can indicate the emulsions properties, thus, nowadays rheology is used in the cosmetic and pharmaceutical industries, even to study the influence of rheological additives on them. Ten emulsions were prepared with 5% and 10% of nonionic emulsifier. Two of them were used as controls while in the others were added thickening agents. Rheological analyses were performed. The results showed that all emulsions are non-Newtonian, thixotropics and viscoelastics fluids. The thickening agents could modify the rheological characteristics of the emulsions and knowing the influence of them is easy to adopt one to reach the desirable performance. © 2013 Copyright Taylor and Francis Group, LLC.

Fatty acids and some antioxidant compounds of Psidium guajava seed oil

Physico-chemical characteristics, fatty acid and tocopherol compositions, total phenolic content and antioxidant activity of crude oil extracted from guava (Psidium guajava var. pomifera) seeds were investigated. Oil yield from the seeds was 14.0%. Data obtained for the analytical indexes compared well with those of others edible oils. The oil showed high levels of unsaturated fatty acids (88.1%), mainly linoleic acid (78.4%). The tocopherol and total phenolic contents in the oil amounted to 29.2 and 92.3 mg/100 g, respectively. The guava seed oil exhibited a great DPPH · scavenging activity showing EC₅₀ of 12.9 g oil/g [DPPH · ] -1 and antiradical efficiency of 7.9×10 -2 . Therefore, the potential utilization of the guava seed oil as a raw material of food, chemical and pharmaceutical industries appears to be favourable and provides the use of a renewable resource, adding value to agricultural products.

Vegetable Oil Derived Solvent, and Catalyst Free Click Chemistry'' Thermoplastic Polytriazoles

Azide-alkyne Huisgen click chemistry provides new synthetic routes for making thermoplastic polytriazole polymers-without solvent or catalyst. This method was used to polymerize three diester dialkyne monomers with a lipid derived 18 carbon diazide to produce a series of polymers (labelled C18C18, C18C9, and C18C4 based on monomer chain lengths) free of residual solvent and catalyst. Three diester dialkyne monomers were synthesized with ester chain lengths of 4, 9, and 18 carbons from renewable sources. Significant differences in thermal and mechanical properties were observed between C18C9 and the two other polymers. C18C9 presented a lower melting temperature, higher elongation at break, and reduced Young's modulus compared to C18C4 and C18C18. This was due to the odd-even effect induced by the number of carbon atoms in the monomers which resulted in orientation of the ester linkages of C18C9 in the same direction, thereby reducing hydrogen bonding. The thermoplastic polytriazoles presented are novel polymers derived from vegetable oil with favourable mechanical and thermal properties suitable for a large range of applications where no residual solvent or catalyst can be tolerated. Their added potential biocompatibility and biodegradability make them ideal for applications in the medical and pharmaceutical industries.