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Search Results: 1 - 10 of 858 matches for " Sibele Berenice Castell?; "
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Synthesis of Mesoporous Material from Chrysotile-Derived Silica  [PDF]
Anderson Joel Schwanke, Christian Wittee Lopes, Sibele Berenice Castell? Pergher
Materials Sciences and Applications (MSA) , 2013, DOI: 10.4236/msa.2013.48A009
Abstract:

Mesoporous MCM-41-type molecular sieves were synthesized using calcined and leached chrysotile and cetyltrimethylammonium bromide as the silica source and structure directing agent, respectively. Powder X-ray diffraction (XRD), N2 isothermal adsorption-desorption, scanning electron microscopy (SEM) and thermogravimetric analysis (TGA) were used to characterize the samples. The calcined and leached chrysotile can be employed as an inexpensive silica source for the formation of low-order MCM-41 mesoporous materials.

Pilariza??o de uma argila brasileira com poliidroxications de alumínio: prepara??o, caracteriza??o e propriedades catalíticas
Pergher, Sibele Berenice Castell?;Sprung, Renato;
Química Nova , 2005, DOI: 10.1590/S0100-40422005000500008
Abstract: montmorillonite clay from brazil was pillared with aluminium polyhydroxications. the influence of aging of the pillaring solution and the concentration of the clay suspension on the properties of the prepared materials was studied. the materials were characterized by chemical analysis, xrd and pore analysis by n2 adsorption. the catalytic properties were evaluated in the cumene cracking reaction. results showed that the pillarization process increases the basal spaces of natural clay from 9.7 to 18.5 ? and the surface area from 41 to 300 m2/g.
Pilariza o de uma argila brasileira com poliidroxications de alumínio: prepara o, caracteriza o e propriedades catalíticas
Pergher Sibele Berenice Castell,Sprung Renato
Química Nova , 2005,
Abstract: Montmorillonite clay from Brazil was pillared with aluminium polyhydroxications. The influence of aging of the pillaring solution and the concentration of the clay suspension on the properties of the prepared materials was studied. The materials were characterized by chemical analysis, XRD and pore analysis by N2 adsorption. The catalytic properties were evaluated in the cumene cracking reaction. Results showed that the pillarization process increases the basal spaces of natural clay from 9.7 to 18.5 and the surface area from 41 to 300 m2/g.
Zeolite A synthesis employing a brazilian coal ash as the silicon and aluminum source and its applications in adsorption and pigment formulation
Bieseki, Lindiane;Penha, Fábio Garcia;Pergher, Sibele Berenice Castell?;
Materials Research , 2013, DOI: 10.1590/S1516-14392012005000144
Abstract: zeolite a was synthesized using the coal ash from siderópolis/rs - brazil. the synthesis was based on a standard iza synthesis using coal ash as the si and al source. xrf analysis showed that the coal ash has a si/al ratio of 1.52, which is close to the si/al ratio required to produce zeolite a (1.0). the synthesized materials were analyzed by xrd, sem and n2 adsorption. more crystalline materials were obtained during synthesis when an additional treatment was applied at a temperature of 353 k at the dissolution of naoh step. the product formed after 4 hours was the most crystalline, but even the product formed after 1 hour proved to be better than that formed using the standard 4 hours iza synthesis. the zeolites synthesized by this method had an adsorption capacity of 120 mg.g-1 for ca2+, half the capacity of commercial zeolite a (300 mg.g-1). it was not possible to obtain blue or green pigments using the synthesized zeolite a.
Decomposi??o do NO sobre Cu suportado em zeólitas
Oliveira, Andréa Marins de;Pergher, Sibele Berenice Castell?;Moro, Celso Camilo;Baibich, Ione Maluf;
Química Nova , 2004, DOI: 10.1590/S0100-40422004000200010
Abstract: direct decomposition of no on copper supported on zeolite catalysts such as mcm-22 and beta was compared with that on the thoroughly studied cu-zsm-5. the catalysts were prepared by ion-exchange in basic media. they were characterized by atomic absorption, surface area, nitrogen adsorption at 77k, x-ray diffraction and temperature programmed reduction. the products of the reaction were analyzed by fourier transform infrared spectroscopy using a gas cell. catalytic activity tests indicated that zeolite catalysts, like beta and mcm-22, lead to no conversion values comparable to zsm-5.
Síntese da zeólita cancrenita a partir de caulim: uma alternativa viável à redu o de impactos ambientais
Anderson Joel Schwanke,Seliane Teresinha Spazzini,Fábio Garcia Penha,Sibele Berenice Castell? Pergher
Tecno-Lógica , 2011,
Abstract: A síntese da zeólita cancrenita foi realizada aproveitando três caulins denominados AD44, Mina e Reagen, utilizados em substitui o às fontes de silício e alumínio já empregadas na síntese de peneiras moleculares, geralmente caras e que necessitam de tratamentos químicos para sua obten o. Os dois primeiros s o caulins naturais e o ultimo é um caulim comercial. Estas argilas foram usadas na forma natural e calcinada a 900oC. As argilas e os materiais obtidos foram caracterizados por difra o de raios-X, medidas de área superficial BET e microscopia eletr nica de varredura. Os resultados mostraram que as argilas calcinadas conduzem à fase cancrenita com maior cristalinidade quando comparada com as argilas naturais. Diferentes fases, tais como sodalita e mesofases entre cancrenita e sodalita também s o formadas. Abstract The synthesis of cancrinite zeolite was accomplished by three types of kaolins called AD44, Mina and Reagen. These materials were used as aluminium and silicon sources in substitution of expensive reactants. The first two types are natural kaolin and the last one is a commercial. These clays were used in natural and calcinated (900oC) forms. The clays and the obtained materials were characterized by X-ray diffraction (XRD) specific superficial area (BET) and scanning electronic microscopy (SEM). The results showed that calcinated clays lead to cancrinite phases with higher cristallinity when compared with the natural clays. Different phases such as sodalite and mesophases between sodalite and cancrinite were formed too.
Decomposi o do NO sobre Cu suportado em zeólitas
Oliveira Andréa Marins de,Pergher Sibele Berenice Castell,Moro Celso Camilo,Baibich Ione Maluf
Química Nova , 2004,
Abstract: Direct decomposition of NO on copper supported on zeolite catalysts such as MCM-22 and Beta was compared with that on the thoroughly studied Cu-ZSM-5. The catalysts were prepared by ion-exchange in basic media. They were characterized by atomic absorption, surface area, nitrogen adsorption at 77K, X-ray diffraction and temperature programmed reduction. The products of the reaction were analyzed by Fourier transform infrared spectroscopy using a gas cell. Catalytic activity tests indicated that zeolite catalysts, like Beta and MCM-22, lead to NO conversion values comparable to ZSM-5.
Programa de gerenciamento de resíduos dos laboratórios de gradua??o da Universidade Regional Integrada do Alto Uruguai e das Miss?es - Campus Erechim
Demaman, Anelise Schwengber;Funk, Suzana;Hepp, Luiz Ubiratan;Adário, Alexandro Magno dos Santos;Pergher, Sibele Berenice Castell?;
Química Nova , 2004, DOI: 10.1590/S0100-40422004000400026
Abstract: this work presents a proposal for the management of residues from teaching laboratories. the main goals of the proposal are: scale reduction of experiments, reuse of residues as raw materials for new experiments and appropriate treatment and storage of residues. the methodology includes standardized labels for residue classification and registration of experimental classes and their residues in files. the management seemed to be efficient, resulting in a reduction of the amount of reagents utilized and residues generated, and an increase of reutilization of residues. a considerable decrease of needed storage space and suitable methods for correct residue disposal were achieved. we expect that all laboratories, including those exclusively for research activities, become involved, in a near future, in the residue management project of uri - campus erechim.
Printability of HDPE/Natural Fiber Composites with High Content of Cellulosic Industrial Waste  [PDF]
Luis Claudio Mendes, Sibele Piedade Cestari
Materials Sciences and Applications (MSA) , 2011, DOI: 10.4236/msa.2011.29181
Abstract: In this paper, a continuous polymeric matrix highly filled with fiber of sugarcane bagasse has been obtained and its feasibility as an ink-absorbing material has been evaluated. In order to study the effect of the amount of cellulose fiber on the surface printability, contact angle measurement using different liquids—water-based inks, ethanol and ink for ink-jet printers—and printing tests were performed on composites of high density polyethylene (HDPE) and sugarcane bagasse (SCB). The composites were processed in a Haake internal mixer, using the SCB without any previous chemical treatment or compatibilizer. The differential scanning calorimetry (DSC) and derivative thermogravimetry (TG/ DTG) revealed an increase in the thermal stability and in the degree of crystallinity of the HDPE. The optical microscopy (OM) and scanning electron microscopy (SEM) showed that the cellulosic material was homogeneously embedded within the HDPE matrix. In order to assess the resistance of the composite sample to the pull strength of the printer, tensile tests were applied to the composites and the results were compared to known paper samples. The best result was achieved in the composite with the highest content of SCB, as well as the shortest drying time.
Thomas Mann e a cena intelectual no Brasil: encontros e desencontros
Paulino, Sibele;Soethe, Paulo;
Pandaemonium Germanicum , 2009, DOI: 10.1590/S1982-88372009000100004
Abstract: thomas mann's brazilian origin, from his mother julia da silva bruhns, made it possible for the adult writer to make contact with brazilian or foreign intellectuals, connected to the cultural scene in brazil. in the first group we find gilberto freyre, sérgio buarque de holanda and erico verissimo. living in brazil, karl lustig-prean (whom later returns to europe), and the translator herbert caro, settled in brazil. also, the direct or indirect contact with thinkers and writers, such as karl loewenstein, heinrich eduard jacob, marte brill and stefan zweig has played a part in bringing thomas mann closer to the brazilian universe. this and other points of contact are described in the present article, which intends to diffuse documents and data long unpublished or unavailable, offering up-to-date approaches to thomas mann works, as well as indicating biographical and documental information related to the writer, regarding his relationship to brazil.
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