Cations
Mostrando 13-24 de 2751 artigos, teses e dissertações.
-
13. VALORES DE REFERÊNCIA DA CONCENTRAÇÃO DE METAIS PESADOS EM SOLOS NA AMAZÔNIA CENTRAL
Considering the size of the Amazon region and the need for studies to establish soil trace metal concentrations in natural environments, the objective of this work was to evaluate heavy metal contents in a toposequence of an Amazon State microbasin. Soil samples were collected in three native forest topographic positions. Samples were opened for analysis by
Quím. Nova. Publicado em: 2020-05
-
14. Influência do processo de aditivação na capacidade de troca de cátions e viscosidade de dispersões de argilas bentoníticas
Resumo No Brasil, as argilas bentoníticas não são naturalmente sódicas e é uma prática industrial a aditivação sódica, uma vez que o íon de sódio expande suas lamelas permitindo a penetração de uma maior quantidade de água. O objetivo foi analisar as influências da adição do carbonato de sódio na argila durante o processo de aditivação, d
Cerâmica. Publicado em: 2020-03
-
15. Experimental and Theoretical Study of LiMn2O4 Synthesized by the Solution Combustion Method Using Corn Starch as Fuel
Lithium manganese oxide, LiMn2O4, was synthesized in two temperature stages, where the first consisted by an ecofriendly solution combustion method at 300 °C. Finally, the as-burned powders were thermal treated at 500 and 700 °C. The structural and morphological changes were evaluated by the Rietveld method and density functional theory (DFT) calculations.
J. Braz. Chem. Soc.. Publicado em: 2020-02
-
16. Clinical and care profiles of children and adolescents with Sickle Cell Disease in the Brazilian Northeast region
Resumo Objetivos: descrever o perfil clínico-epidemiológico e assistencial dos pacientes pediátricos com doença falciforme. Métodos: estudo descritivo da totalidade (48) de crianças e adolescentes portadores de doença falciforme, atendidos em hospital de referência da rede pública da Paraíba. As informações obtidas em prontuários e entrevistas
Rev. Bras. Saude Mater. Infant.. Publicado em: 13/01/2020
-
17. ONE-POT DIASTEREOSELECTIVE SYNTHESIS OF CHIRAL TRICYCLIC L-CYSTEINE AND D-PENICILLAMINE DERIVATIVES: A LABORATORY EXPERIMENT
A one-pot diastereoselective synthesis of thiazolidine-ring fused systems derived from enantiomerically pure amino acids, L-cysteine or D-penicillamine, and achiral succindialdehyde is described as an experiment to be carried out by upper-division undergraduate students in a laboratory classroom. Reactions were performed under mild conditions, the products w
Quím. Nova. Publicado em: 2020-01
-
18. Serpentinites: Mineral Structure, Properties and Technological Applications
Serpentine is a versatile mineral family rich in Mg silicate with several polymorphic phases, mainly antigorite and lizardite, all of them with similar chemical composition (Mg3Si2O5(OH)4). Their structures are generally composed of octahedral layers rich in Mg[MgO2(OH)4]6- , attached to a tetrahedral silicate [Si2O5]2- sheet. The unique physicochemical prop
J. Braz. Chem. Soc.. Publicado em: 2020-01
-
19. Cation Vacancies in NiFe2O4 During Heat Treatments at High Temperatures: Structural, Morphological and Magnetic Characterization
Nickel ferrite (NiFe2O4) was synthesized by mixing stoichiometric amounts of α-Fe2O3 and NiO using mechanical milling and heat treatments at high temperatures. The physical characterization of the samples was carried out using X-ray diffraction, infrared and Raman spectroscopies, Mössbauer spectrometry, magnetization measurements, scanning electron microsc
Mat. Res.. Publicado em: 20/12/2019
-
20. Phytodesalination of a moderately saline soil combined with two inorganic amendments
ABSTRACT The shortage of water and the increasing salinity are the main limiting environmental factors that directly affect the establishment and the development of crops. In this research, phytodesalination capacity of Sesuvium verrucosum was evaluated alone and in combination with agricultural gypsum (CaSO4·2H2O) and Polisul-C, in order to remedy a modera
Bragantia. Publicado em: 13/12/2019
-
21. Lateral loss of clay in the genesis of Luvisols in the Semi-Arid Depression of the Jequitinhonha Valley, Minas Gerais - Brazil
RESUMO Os solos da região semi-árida de Minas Gerais possuem pequena profundidade; consistência dura, muito dura ou mesmo extremamente dura quando seca e muito plástica e muito pegajosa quando úmida; estrutura colunar ou em blocos angulares e fendilhamento significativo ao longo do perfil no período seco, entretanto eles não foram profundamente estuda
Ciênc. agrotec.. Publicado em: 05/12/2019
-
22. Layered Double Hydroxides with the Composition Mn/Al-SO4-A (A = Li, Na, K; Mn:Al ca. 1:1) as Cation Exchangers
Hydrated Mn/Al-SO4-A (A = Li, Na or K) layered double hydroxides with M2+:M3+ molar ratio close to 1:1 were synthesized by co-precipitation with increasing pH. All phases presented solvated alkali metals and sulfate as intercalated species. In the exchange reactions, when sulfate solutions of alkali metals were used, sodium could be partially replaced by pot
J. Braz. Chem. Soc.. Publicado em: 16/09/2019
-
23. Relief Position and Soil Properties under Continuous Banana Cropping in Subhumid Climate in Northeast Brazil
ABSTRACT Sequences of thick and eroded soils in hills surfaces are cultivated with banana since the beginning of the last century in the Northeast of Pernambuco (PE), Brazil. Measurements of soil properties depending on soil slope under intensive agricultural cultivation are limited mostly as the pedogenetic approach. This study aimed to identify the dominan
Rev. Bras. Ciênc. Solo. Publicado em: 09/09/2019
-
24. Influence of reactivity and mineralogical composition on instability due to the disintegration of shales from Paraíba and Ceará States, Brazil
Resumo Este trabalho teve como objetivo correlacionar a reatividade e composição mineralógica de folhelhos à sua desintegração. Para tanto, foram caracterizadas cinco amostras de folhelho das Bacias do Rio do Peixe e Araripe, localizadas nos estados brasileiros da Paraíba e Ceará e, para fins de comparação, foi utilizada uma amostra de argila bento
Cerâmica. Publicado em: 15/08/2019