936 resultados para Hero worship
Resumo:
We report an efficient one-pot conversion of glycerol (GLY) to methyl lactate (MLACT) in methanol in good yields (73 % at 95 % GLY conversion) by using Au nanoparticles on commercially available ultra-stable zeolite-Y (USY) as the catalyst (160 °C, air, 47 bar pressure, 0.25 M GLY, GLY-to-Au mol ratio of 1407, 10 h). The best results were obtained with zeolite USY-600, a catalyst that has both Lewis and Brønsted sites. This methodology provides a direct chemo-catalytic route for the synthesis of MLACT from GLY. MLACT is stable under the reaction conditions, and the Au/USY catalyst was recycled without a decrease in the activity and selectivity. From glycerol to green building blocks and solvents! An efficient, base-free conversion of glycerol to methyl lactate in methanol is reported, achieving good yields (73 % at 95 % glycerol conversion) using Au/ultra-stable zeolite-Y (USY) as the catalyst and environmentally benign oxygen as the oxidant by combining two separate reaction steps efficiently in a one pot procedure. The Au/USY catalyst can be recycled without a decrease in the activity and selectivity. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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The phenomenon of microscopic hot-spots, during the calcination of MCM-41, was investigated by quantifying the magnitude of the temperature increase during the calcination of a soft MCM-41 mesophase using a SAXS comparative study. This was performed by thermally treating a soft material that was detemplated via Fenton chemistry followed by equilibrating and drying in a low-surface-tension solvent (n-butanol or N,N-dimethylformamide); these samples have limited structural shrinkage. The resulting samples were thermally treated at increasing temperatures, and the structural shrinkage was compared with that of the directly calcined material. By comparing the structural shrinkage, it was found that the microscopic temperature increase would fall between 190 and 250 C, as deduced from N,N-dimethyl-formamide and n-butanol. The order of magnitude of the temperature increase appears to be consistent with the well-known glow effect. It is, however, substantially higher than the experimentally determined macroscopic temperature increase. Several aspects are discussed to interpret this difference. © 2013 Elsevier B.V.
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A mild protocol that allows the template removal of soft un-aged silica nanoparticles was investigated. After oxidizing the organic template by Fenton chemistry, a good structural preservation is only achieved when the material is equilibrated and dried in a low-surface tension solvent. This avoids excessive capillary stress induced by the high surface tension of water, a major component in the Fenton reaction medium. The Fenton reaction should be carried out under mild conditions as well; otherwise the sample deteriorates by extensive hydrolysis, and capillary stress, and the structural ordering diminishes severely. We propose employing 10 ppm Fe concentration at 70 °C for 24 h for the cetyltrimethylammonium bromide template. The proposed protocol involves 2 steps resulting in an overall significantly higher pore volume attributed to the wider pores and limited particle agglomeration, while the calcined counterpart evidences aggregation and loss of the hexagonal ordering. n-BuOH exchange is unnecessary when the mesophase is stabilized by ageing, as the structure resists the water capillary stress. © The Royal Society of Chemistry 2013.
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In this work a direct activation route of zeolites is assessed. It consists of NH4-exchanging the as-synthesized solids before removing the organic template. Calcination afterwards serves to combust the organic template and creates the Brønsted sites directly; thus applying merely a single thermal step. This method simplifies their activation and the material suffers less thermal stress. The approach was particularly effective for microcrystalline beta and ferrierite zeolites. Thorough investigation of the template content and materials' texture points out to three relevant effects that can explain the effective exchange process: partial removal of the template during exchange creates substantial microporosity (ferrierite), the remaining template is reorganized within the pores (ferrierite) and finally, void space can exist due to the non-perfect matching between the network and template (beta). This shorter method appears suited for microcrystalline zeolites; it was ineffective for crystalline MFI types. © 2013 Elsevier B.V. All rights reserved.
Resumo:
High surface area nanosized α-alumina has been obtained by thermally treating a sol-gel-derived mesophase at 1200 C; the mesophase was synthesized by a sol-gel route involving evaporation induced self-assembly (EISA) of a hydrolyzed gel from Al-tri-sec-butoxide in s-BuOH in the presence of a nonionic surfactant (EO20PO70EO20), HCl as catalyst, and water (H2O/Al = 6). The activated material renders moderate surface areas of about 8.4-10 m2 g-1, associated with significant crystallite coarsening. The key aspect to produce smaller crystallites is making the mesophase more resistant to coarsening. This was achieved by enhancing the condensation step by treating the hydrolyzed gel with tetrabutyl ammonium hydroxide (TBAOH) before evaporation. The characteristics of the mesophase indicate condensation of the primary particles with less AlO5 unsaturated sites, at the expense of a lower solid yield due to small crystallites dissolution. The activated TBAOH condensed EISA material is composed of α-alumina aggregated crystallites of about 60-100 nm, and the material possesses surface areas ranging from 16 to 24 m2 g -1 due to the improved resistance to coarsening. At least two aspects are suggested to play a role in this. The worm-hole morphology of the mesophase aggregates yields high particle coordination, which favors densification rather than coarsening. Furthermore, the decrease of the AlO5 defect sites by the TBAOH condensation makes the mesophase less reactive and consequently more resistant to coarsening. © 2013 American Chemical Society.
Resumo:
The potential use of the solvothermal extraction (SE) as a preliminary step to calcination for detemplating SBA-15 mesophases is investigated; aiming to reduce the amount of organics to be burnt and thereby the corresponding structural shrinkage. A systematic study was carried out by soxhlet extraction on mesophases hydrothermally aged between 90 and 130 C. The mesophases containing variable amounts of template were then treated by calcination or pyrolysis/calcination. TGA was applied to quantify the template amount after the various treatments. The as obtained materials were characterized by SAXS and Ar ad/desorption for structural and textural information while 1H NMR gave information about the integrity of the as-recycled template. The study shows that solvothermal conditions remove considerably the template, typically from 50 to 10-20 wt.%, mainly extracted from the primary mesopores. Possible reuse of the extracted template is questionable as it is poor in polyethyleneoxide compared to the synthesis block-copolymer, Pluronic P123. For all thermal protocols applied (direct calcination, calcination after solvent-extraction or pyrolysis/calcination after solvent extraction), the thermal shrinkage decreases with the aging temperature; that is consistent with the condensation degree of the silica. For each mesophase, it was found that the thermal shrinkage becomes less pronounced when the material is fully templated; thus the template can serve as structural support or can control the mass transfer of O2 and thereby the oxidation rate of the template burning. © 2013 Elsevier Inc. All rights reserved.
Resumo:
Commercially available γ-Al2O3 was calcined at temperatures between 500 and 1200 °C and tested for its performance in the oxidative ethylbenzene dehydrogenation (ODH) over a wide range of industrially-relevant conditions. The original γ-Al2O 3, as well as η- and α-Al2O3, were tested. A calcination temperature around 1000/1050 °C turned out to be optimal for the ODH performance. Upon calcination the number of acid sites (from 637 to 436 μmol g-1) and surface area (from 272 to 119 m 2 g-1) decrease, whereas the acid site density increases (from 1.4 to 2.4 sites per nm2). Less coke, being the active catalyst, is formed during ODH on the Al-1000 sample compared to γ-Al 2O3 (30.8 wt% vs. 21.6 wt%), but the coke surface coverage increases. Compared with γ-Al2O3, the EB conversion increased from 36% to 42% and the ST selectivity increased from 83% to 87%. For an optimal ST selectivity the catalyst should contain enough coke to attain full conversion of the limiting reactant oxygen. The reactivity of the coke is changed due to the higher density and strength of the Lewis acid sites that are formed by the high temperature calcination. The Al-1000 sample and all other investigated catalysts lost ODH activity with time on stream. The loss of selectivity towards more COX formation is directly correlated with the amount of coke. © The Royal Society of Chemistry 2013.
Resumo:
The metal catalyzed hydrogenolysis of the biomass-derived THF-dimethanol to 1,2,6-hexanetriol using heterogeneous catalysts was investigated. Bimetallic Rh-Re catalysts (4 wt% Rh and a Re/Rh (mol. ratio of 0.5) on a silica support gave the best performance and 1,2,6-hexanetriol was obtained in 84% selectivity at 31% conversion (120 C, 80 bar, 4 h); the selectivity reaches a maximum of 92% at 80 C. The product distribution at prolonged reaction times or higher temperatures or both shows the formation of diols and mono-alcohols, indicating that the 1,2,6-hexanetriol is prone to subsequent hydrodeoxygenation reactions. Different silica supports were investigated and optimal results were obtained with an amorphous silica featuring an intermediate surface area and an average mesopore size of about 6 nm. TPR and XPS surface analysis support the presence of mixed Rh and Re particles. The redox Reδ+/ReTotal surface ratio correlates with the conversion in a volcano type dependency. Both gas phase as well as Rh200Re1OH cluster DFT calculations support an acid-metal bifunctional mechanism and explain the products distribution. © 2013 Elsevier B.V. All rights reserved.
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An efficient route to stabilize alumina mesophases derived from evaporation-induced self-assembly is reported after investigating various aspects in-depth: influence of the solvent (EtOH, s-BuOH, and t-BuOH) on the textural and structural properties of the mesophases based on aluminum tri-sec-butoxide (ATSB), synthesis reproducibility, role of nonvolatile acids, and the crystallization and thermal stability of the crystalline counterparts. Mesophase specific surface area and pore uniformity depend notably on the solvent; s-BuOH yields the highest surface area and pore uniformity. The optimal mesophase synthesis is reproducible with standard deviations in the textural parameters below 5%. The most pore-uniform mesophases from the three solvents were thermally activated at 1023 K to crystallize them into γ-alumina. The s-BuOH mesophase is remarkably thermally stable, retaining the mesoscopic wormhole order with 300 m2/g (0.45 cm3/g) and an increased acidic site density. These features are not obtained with EtOH or t-BuOH, where agglomerated γ-Al2O3 crystallites are formed with lower surface areas and broader pore size distributions. This was rationalized by the increase of the hydrolysis rate using EtOH and t-BuOH. t-BuOH dehydrates under the synthesis conditions or reacts with HCl, situations that increase the water concentration and rate of hydrolysis. It was found that EtOH exchanges rapidly, producing a highly reactive Al-ethoxide, thus enhancing the hydrolysis rate as well. Particle heterogeneity with random packing of fibrous and wormhole morphologies, attributed to the high hydrolysis rate, was observed for mesophases derived from both solvents. Such a low particle coordination favors coarsening with enlargement of the pore size distribution upon thermal treatment, explaining the lower thermal stability. Controlled hydrolysis and formation of low-polymerized Al species in s-BuOH are possibly responsible for the adequate assembly onto the surfactant. This was verified by the formation of a regular distribution of relatively size-uniform nanoparticles in the mesophase; high particle coordination prevents coarsening, favors densification, and maintains a relatively uniform pore size distribution upon thermal treatment. The acid removal in the evaporation is another key factor to promote network condensation in this route. © 2013 American Chemical Society.
Resumo:
This study analyzes Carmen de Burgos' European travel literature, and focuses on two themes: education and travel literature as a literary genre. An examination of her travel literature reveals two essential elements related to her view of education. The first is the influence that the European educational system had on her way of thinking, particularly with respect to the idea of tolerance, the practice of hygiene, and the important role of nature in education. The second is the development of her view of education as the foundation for the emancipation of women in Spain. Carmen de Burgos espoused the view that the reform of the Spanish educational system was the primary and foundational goal to further social, political and economic progress of women in Spain at the end of the 19th and beginning of the 20th Century. ^ In the second part of this dissertation I support the theory that her travel literature was her main source to convey to Spanish women the need for social change. I do this by analyzing four properties that are considered characteristic of women's travel literature: (1) the woman as a hero, (2) scientific authority of women, (3) feminine style, and (4) feminine content. I argue that Carmen de Burgos's travel literature uses these properties to facilitate her access to women audiences and to assure that this audience regarded her as an authoritative voice. ^
Resumo:
THE FULLNESS OF TIME is a novel about the quest for identity that transcends the limitations of moral duty, social status, and cultural conventions. Set in Tarpon Springs, Florida, in 1969, it is the story of Victor Lucas, a young Greek immigrant forced to go to war in Vietnam in another man's place in order to save the woman he loves. He must survive the war to return and reclaim his love and his rightful place in society. Based on the archetypal hero's quest as articulated by Joseph Campbell, the narrative is told from the limited third-person perspective of the main character. Though the journey is particular to Tarpon Springs in the 1960s, it echoes the human struggle and triumph in the wanderings of Ulysses. The novel's influences include Thomas Hardy's The Mayor of Casterbridge, but is also thematically related to contemporary works exploring cultural turbulence and upheaval.
Resumo:
The Gnostic Mass of the Ecclesia Gnostica Catholica (E.G.C.) suggests a heterosexual gender binary in which the female Priestess seated on the altar as the sexual and fertile image of the divine feminine is directed by the male Priest’s activity, desire and speech. The apparent contradiction between the empowered individual and the polarized gender role was examined by comparing the ritual symbolism of the feminine with the interpretations of four Priestesses and three Priests (three pairs plus one). Findings suggest that the Priestess’ role in the Gnostic Mass is associated with channeling, receptivity, womb, cup, and fertility, while the Priest’s role is associated with enthusiasm, activity, phallus, lance, and virility. Despite this strong gender duality, the Priestesses asserted that their role was personally and spiritually empowering, and they maintained heterosexual and polarized gendered roles are necessary in a transformative ritual which ultimately reveals the godlike unified individual.
Resumo:
This master‘s thesis presents an analytical reading of Cyro dos Anjos (1906-1994)‘s novel O amanuense Belmiro (1937) and its main objective is to analyze the way some aspects of melancholy, together with the notion of memory, diary writing as well as time permeate all the narrative of this unique book in the Brazilian literary scenario. Anjos‘ novel is an atypical work in the fiction of the 1930s as it is considered a dissonant voice compared to the regional and social productions of the time it was published. Among other themes, the book depicts the relationship of man with life; the present and the past; love and frustrations and the hero in search of itself. Belmiro Borba, character-narrator, is a sentimental man, often handicapped by his inner life. For this matter, Borba decides to write a book in order to register his stories, memories, feelings, meditations and illusions. From this perspective, this research aims to deal with issues related to the aesthetics of melancholy, especially its relationship with the creative process, which belongs to Borba‘s attempt to write literature. Throughout our academic research, we used the work of Aristotle (1998), Lambotte (2000), Benjamin (2011) and Kristeva (1989) to articulate relevant issues of melancholy; Halbwachs (2006) on the concept of memory, among other theorists who were essential to the completion of this study.
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This inquiry looks it to think of the body through Hedonistic Philosophy of Michel Onfray. To compose his written, the philosopher launches strong criticism to the asceticism (constituted by the philosophical tradition and by the monoteístas religions), accusing it of despise the body and the pleasure of his teachings, anchored by the Christian moral. However, his philosophy defends the hedonismo and emphasizes the pleasure as an ethical / moral beginning, which aims the other as much as the individual himself, elevating the body and his potentialities through five senses. The contemplated philosophy allowed us think on the Physical Education, area wich, traditionally, was tied to the execution of disciplinary tasks of the body, disregarding the sensibility of his pedagogic practice. In this scenery, there is an ideal of body that attacks us daily, intensified by this area, which turns in the ethical problem of the body. From then, we launch our questions: From Michel Onfray philosophy, how the body shapes between the asceticism and the hedonismo?, What are the possible implications for the Physical Education? Ruled in the method of the Hedonistic Materialism, proposed by Michel Onfray, we think about this inquiry on two central points that contemplate our categories of study to be known: Glorious body and Loose living Body. We resort to Michel Onfray´s books, as well as, interviews given by the author in magazines / newspapers to help in our inquiry intentions. For the approach ethics / esthetics in the Physical Education, we use the texts of Silvino Santin and Hugo Lovisolo. Besides, we brought the cinema dialog. We classify this inquiry as a true Odyssey that transported us to unknown places and as a return to other already visited. This travel provided teachings that will help our wisdom on how survive the life, alerting us for the worship to the body like the cultivation of ourselves, and not as search of reaching physical standards stipulated by the society in force.
Resumo:
The churches in Brazil have shown themselves as a very important space in the musical training of many individuals. However, we perceive in many of them an excluding and merely performatic musical posture. Their argument is the fact that they want to give worship to the Divine Being and, for that, they must always offer their best. Besides that, the culture of the talent and the gift has provoked the selection of people in the ecclesiastical musical practices. The musical theatre, also practiced in this context, has been following the same principles. Understanding that musical practices must be accessible to all people, we have seen, through the studies of Amelia Santa Rosa, 2006 and 2012, the musical theatre, for its various possibilities, as an important tool for the music teaching in this context in an integrating, motivating, interdisciplinary and liberating way. For this reason, through an action research, this work has aimed to investigate the applicability of the musical theatre as a pedagogical practice in the context of the Igreja Batista da Esperanca (Hope Baptist Church), in Natal-RN, verifying the impact of this experience to the ones involved. In order to accomplish this, we carried out the construction of a musical with all of the ones who wanted to be a part of this research, having or not having previous musical experiences. The data collection was made through the field diary, semi-structured interviews with the cast of the musical and pictures and videos of rehearsals and presentations. The main issues highlighted were categorized and properly analyzed, which showed us how much the musical theatre can be used as a musical pedagogical tool also effective in the ecclesiastical context. Thus, another conception of artistic endeavor could be brought to churches, contributing to the inclusion of new participants in their musical practices, expanding the studies on the musical theatre and the presence of music in these spaces a bit more, causing other future studies.