47,998 research outputs found
Otro título: Ciudad:
No full textTítulo tomado de la cubiertaDirector : Víctor de la Serna; Redactor-jefe : Eduardo Blanco-AmorA partir de n. 18, 39 c
Fracionamento do óleo essencial de Patchouli [Pogostemon cablin (Blanco) Benth.] obtido por extração supercrítica
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia Química.O fracionamento do óleo essencial de patchouli [Pogostemon cablin (Blanco) Benth.] extraído com dióxido de carbono supercrítico (CO2_SC) foi estudado. Este óleo essencial é muito usado pela indústria de cosméticos e perfumaria como excelente fixador de aromas. Adotando-se pressão e temperatura de trabalho em 100 bar e 32°C, respectivamente, foram estudados alguns parâmetros nunca antes averiguados para o patchouli. O trabalho se dividiu em quatro frentes de estudo: aumento de rendimento variando o tempo de extração e tempo estático; análise do tamanho ideal de partícula; épocas de colheita; composição química do óleo essencial. O tempo estático combinado com o tempo de coleta de amostras foi estudado com o objetivo de aumentar o rendimento do processo, resultando em um tempo ideal de 20 minutos de tempo estático e de tempo para coleta de amostras. Três tamanhos "médios" de partículas foram estudados à duas diferentes vazões de solvente. O tamanho de partícula ideal para a extração supercrítica do óleo essencial de patchouli foi de 0,346 mm à vazão de 1,2 L/min de CO2. Lotes de folhas de patchouli colhidas em diferentes épocas do ano foram usados para extração de seu óleo essencial. A época do ano nas quais se obtiveram melhores rendimentos foi no inverno. A composição química do óleo essencial de patchouli foi estudada com a intenção de saber a que tempo de processo os principais compostos de interesse (patchoulol e a-bulneseno) são extraídos. As amostras de óleo essencial analisadas forneceram resultados suficientes para se traçar o perfil de concentração destes compostos com o tempo de extração. Sabendo-se o tempo ideal de coleta de amostras, pode-se estabelecer um método de fracionamento para óleo essencial de patchouli. The fractionation of the essential oil of patchouli [Pogostemon cablin (Blanco) Benth.] extracted with supercritical carbon dioxide (CO2_SC) was studied. This oil is widely used by industries of cosmetics and fragrances. Bringing up of work pressure and temperature at 100 bar and 32 ° C, respectively, were studied some parameters never before investigated for the patchouli. The work was divided into four subjects of study: increasing yield varying the static period and the total time of extraction; analysis of the optimal particle size; harvest period; chemical composition of the essential oil. The static period combined with the time of collection of samples was studied with the objective of increasing the yield of the process, resulting in an ideal time of 20 minutes of static period and time for collection of samples. Three "averages" particles sizes were studied for two different flows of solvent. The ideal particle size for the supercritical extraction of essential oil of patchouli was 0.346 mm, at flow rate of 1.2 L / min of CO2. Lots of patchouli leaves harvested at different times of the year were used for extraction of its essential oil. The time of the year which it was obtained better yield is the winter. The chemical composition of the essential oil of patchouli was studied with the intention of knowing that process time the main compounds (patchoulol and a-bulnesene) are extracted. Samples of essential oil analyzed results provided sufficient to trace the profile of concentration of these compounds. Knowing the perfect time of collection of samples, can be possible to establish a method for the fractionation of patchouli essential oil
Design and Thermal and Spectroscopic Characterization of novel architecture’s POSS nanoparticles
No full textPolyhedral oligomeric silsesquioxanes (POSSs), with Si vertices interconnected by –O– linkages, form three-dimensional nanometer size cage structures with substituents attached to silicon atoms. These substituents may contain reactive groups, such as hydroxyl or isocyanate. A combination of a rigid inorganic nanocore with organic vertex groups makes POSS molecules useful hybrid building blocks that can be chemically incorporated in the polymer matrix by copolymerization, grafting or reactive blending, or physically mixed by solvent casting or polymer processing by using, for example, the extrusion technique [1]. The use of POSSs for making polymer composites has grown exponentially since the last few years of the 20th century. In comparison with the other most commonly used fillers, POSSs possess the advantage of being molecules. Thus, this allows us to combine their nano-sized cage structures, which have dimensions that are similar to those of most polymer segments and produce a particular and exclusive chemical composition. These characteristics linked with their hybrid (inorganic–organic) nature allow researchers to modify POSS according to particular needs or original ideas, before incorporating them into polymers [2].
Figure 1. Molecular structure of the prepared and investigated POSSs
In this context, our research group at the University of Catania, in collaboration with eminent researchers in the field, tested the stabilization of different polymers, synthetics or naturals, such as polyethersulfone (PES), ethylene propylene diene monomer (EPDM), polyethylene oxide (PEO), and chitosan by the incorporation of polyhedral oligomeric silsesquioxanes (POSS) molecules [3-6]. Represented in their most common form by the symbol T8 and having a diameter usually falling in the range of 1.5–3 nm, POSS molecules comprise a silicon and oxygen cage completed by organic groups that are covalently bonded with silicon atoms. Novel architectures of POSS with various organic groups were synthesized by using corner capping reaction in order to verify their polimeryzability in the presence of monomer. In this work, after a spectroscopic investigation aiming at verify that the obtained molecules have the structure for which they were designed, their thermal behavior in terms of resistance to thermal degradation were evaluated by means of thermogravimetric analysis (TGA). The obtained temperatures at 5% mass loss (T5%) were compared with each other and with those of the POSSs previously designed and studied by us.
Bibliography
[1] Lichtenhan, J.D., Pielichowski, K., Blanco, I. POSS-Based Polymers. Polymers 2019, 11, 1727
[2] Blanco, I. The Rediscovery of POSS: A Molecule Rather than a Filler. Polymers 2018, 10, 904.
[3] Cicala, G., Blanco, I., Latteri, A., Ognibene, G., Agatino Bottino, F., Fragalà, M.E. PES/POSS Soluble Veils as Advanced Modifiers for Multifunctional Fiber Reinforced Composites. Polymers 2017, 9, 281
[4] Zaharescu, T., Blanco, I., Bottino, F.A. Antioxidant activity assisted by modified particle surface in POSS/EPDM hybrids. Appl. Surf. Sci. 2020, 509, 144702
[5] Legnani, L.; Iannazzo, D.; Pistone, A.; Celesti, C.; Giofrè, S.; Romeo, R.; Di Pietro, A.; Visalli, G.; Fresta, M.; Bottino, P.; et al. Functionalized polyhedral oligosilsesquioxane (POSS) based composites for bone tissue engineering: Synthesis, computational and biological studies. RSC Adv. 2020, 10, 11325–11334
[6] Stipanelov Vrandečić, N., Erceg, M., Andričić, B., Blanco, I., Bottino, F.A. Characterization of poly(ethylene oxide) modified with different phenyl hepta isobutyl polyhedral oligomeric silsesquioxanes. J. Therm. Anal. Calorim. 2020, 142, 1863–187
Rescatar del olvido (Azorín en Blanco y Negro)
No full textSome articles written by José Martínez Ruiz for the Blanco y Negro illustrated weekly between 1904 and 1910 were analysed, according to the requirements of this monograph. They were collected by José García Mercadal, in a volume entitled En lontananza [In the distance] (1963), alongside many others from varying backgrounds. These collaborations were a kind of literary workshop for Azorín, given that those not made into a book would serve as trials for works or parts of subsequent works. At other times, our author would re-elaborate existing works, giving them new dimensions. Finally, many beautiful stories have remained forgotten in the pages of Blanco y Negro – works which would not be seen in any volume of Azorín’s wide range of works.Atendiendo a las exigencias de este monográfico, se estudian algunos artículos que José Martínez Ruiz escribió para el semanario gráfico Blanco y Negro entre 1904 y 1910. Son, precisamente, aquellos que, en 1963, José García Mercadal recogió en el volumen titulado En lontananza, entre otros tantos de diversa procedencia. Estas colaboraciones fueron una especie de taller literario para Azorín, puesto que las que no pasaron a un libro sirvieron como probaturas para obras o partes de obras posteriores. Otras veces, en cambio, nuestro autor reelaboró escritos ya existentes, dándoles una nueva dimensión. Por último, en las páginas de Blanco y Negro quedaron olvidados bellos cuentos que luego no encontraron cabida en ningún volumen de la amplia creación azoriniana
Weak C-H×××O and C-H×××F-C hydrogen bonds in the Oxirane-Trifluoromethane Dimer
No full textThe oxirane-trifluoromethane dimer generated in a supersonic expansion has been characterized by Fourier transform microwave spectroscopy. The rotational spectra of the parent species and of its two 13C isotopomers in combination with ab initio calculations have been used to establish a Cs geometry for the dimer with the two monomers bound by one C-HâââO and two C-HâââF-C hydrogen bonds. An overall bonding energy of about 6.7 kJ/mol has been derived from the centrifugal distortion analysis. The lengths of the C-HâââO and C-HâââF hydrogen bonds, r(OâââH) and r (FâââH), are 2.37 and 2.68 Å, respectively. The C-HâââF-C interactions give rise to the HCF3 internal rotation motion barrier of 0.55(1) kJ/mol, which causes the A-E splittings observed in the rotational spectra. The analysis of the structural and energetic features of the C-HâââO and C-HâââF-C interactions allows us to classify them as weak hydrogen bonds. Ab initio calculations predict these weak interactions to produce blue shifts in the C-H vibrational frequencies and shortenings of the C-H lengths
FIGURE 2. Lockhartia endresiana M.A.Blanco. A. Plant habit. B. Flower, front view. C. Flower, lateral view. D in Four new species of Lockhartia (Orchidaceae, Oncidiinae)
No full textFIGURE 2. Lockhartia endresiana M.A.Blanco. A. Plant habit. B. Flower, front view. C. Flower, lateral view. D. Same as previous, with sepals and lateral petals removed. E. Dissected perianth parts (flattened, except lateral petal on right), with column in center (ventral view). F. Floral bract, flattened. Scale bar: 5.5 cm (for A), 1.0 cm (for B–F). Drawing by the author; A, based on Carballo et al. 40 (CR); B–F based on Blanco 1803 (FLAS).Published as part of Blanco, Mario A., 2014, Four new species of Lockhartia (Orchidaceae, Oncidiinae), pp. 134-146 in Phytotaxa 162 (3) on page 138, DOI: 10.11646/phytotaxa.162.3.2, http://zenodo.org/record/513204
The educative dimension of the life of Rufino Blanco y Sánchez (1861-1936)
No full textFrente al ideal krausista sobre la cultura y la enseñanza, Rufino Blanco desarrolló
una intensa actividad pedagógica y propuso un programa docente en la Escuela Superior de
Magisterio de Madrid. Siendo autor regeneracionista de creencias cristianas, se opuso a la
secularización de la vida pública y a la neutralidad religiosa en la escuela. Podría ser situado
en la corriente católica, representada por Manjón, Ruiz Amado, Pedro Poveda y otros. De
fundamentación neoescolástica, no dudó en dialogar con las corrientes pedagógicas de la época
(Pestalozzi, Dewey, Mercier). En estas líneas se recoge un retrato pedagógico, intelectual y
humano de este pedagogo español.Faced with the Krausist ideal of culture and education, Rufino Blanco developed
an intense pedagogical activity and proposed a teaching program at the Escuela Superior de
Magisterio in Madrid. Being a regenerationist author of Christian beliefs, he opposed the
secularization of public life and religious neutrality at school. It could thus be situated in
the Catholic stream, represented by Manjón, Ruiz Amado, Pedro Poveda and others. With a
neo-scholastic foundation, he did not hesitate to dialogue with the pedagogical currents of the time (Pestalozzi, Dewey, Mercier). In these lines a pedagogical, intellectual and human
portrait of this Spanish pedagogue is collected.Educació
La dimensión educativa de la vida de Rufino Blanco y Sánchez (1861-1936)
No full textFaced with the Krausist ideal of culture and education, Rufino Blanco developed an intense pedagogical activity and proposed a teaching program at the Escuela Superior de Magisterio in Madrid. Being a regenerationist author of Christian beliefs, he opposed the secularization of public life and religious neutrality at school. It could thus be situated in the Catholic stream, represented by Manjón, Ruiz Amado, Pedro Poveda and others. With a neo-scholastic foundation, he did not hesitate to dialogue with the pedagogical currents of the time (Pestalozzi, Dewey, Mercier). In these lines a pedagogical, intellectual and human portrait of this Spanish pedagogue is collected.Frente al ideal krausista sobre la cultura y la enseñanza, Rufino Blanco desarrolló una intensa actividad pedagógica y propuso un programa docente en la Escuela Superior de Magisterio de Madrid. Siendo autor regeneracionista de creencias cristianas, se opuso a la secularización de la vida pública y a la neutralidad religiosa en la escuela. Podría ser situado en la corriente católica, representada por Manjón, Ruiz Amado, Pedro Poveda y otros. De fundamentación neoescolástica, no dudó en dialogar con las corrientes pedagógicas de la época (Pestalozzi, Dewey, Mercier). En estas líneas se recoge un retrato pedagógico, intelectual y humano de este pedagogo españo
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