Consulta: subjectFacets:"Iron oxides"
Registros recuperados: 10
Data/hora: 01/06/2024 09:54:13

EFFECTS OF CLAY FRACTION MINERALOGY ON PHYSICAL ATTRIBUTES OF A YELLOW ULTISOL TREATED WITH CHISELING
Provedor de dados: 70
Autores: Nogueira,Deise C. S.; Fernandes,Carolina; Souza,Luma C. de; Camargo,Lívia A.; Ferraudo,Antonio S.
ABSTRACT The objective of this study was to evaluate the influence of minerals in the clay fraction on physical attributes of Yellow Ultisol cultivated with sugarcane and prepared with two different treatments: chiseling across the entire area and chiseling only in planting rows. The samples were collected from four layers of soil at eight months after planting. We assessed the texture of the soil, levels of iron extracted by dithionite-citrate-bicarbonate (DCB) and ammonium acid oxalate (AAO), ratio of kaolinite/(kaolinite + gibbsite), soil bulk density, and soil penetration resistance. The first area showed a higher ratio of kaolinite/(kaolinite + gibbsite) and the second area had greater levels of iron extracted by DCB. Levels of iron extracted by DCB...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Iron oxides; Kaolinite; Soil bulk density; Soil penetration resistance.
Ano: 2020
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162020000400433

Bacterial symbionts and mineral deposits in the branchial chamber of the hydrothermal vent shrimp Rimicaris exoculata: relationship to moult cycle
Provedor de dados: 5
Autores: Corbari, Laure; Zbinden, Magali; Cambon-bonavita, Marie-anne; Gaill, Françoise; Compere, Philippe.
The shrimp Rimicaris exoculata is considered a primary consumer that dominates the fauna of most Mid-Atlantic Ridge hydrothermal ecosystems. The shrimps harbour in their gill chamber an important ectosymbiotic community of chemoautotrophic bacteria associated with iron oxide deposits. The settlement and development of this ectosymbiosis was investigated using microscopy techniques (light microscopy, LM; and scanning, transmission and environmental scanning electron microscopy: SEM and ESEM, respectively) for shrimps from 2 different vent fields (Rainbow, 36 degrees 14.0' N and TAG, 26 degrees 08.0' N). The results revealed a bacterial re-colonisation after each exuviation and a development of the bacterial community in 5 steps in relation to the moult...
Tipo: Text
Palavras-chave: Iron oxides; Ectosymbiosis; Moult cycle; Shrimp; Hydrothermal vents.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/publication-4626.pdf

Chemical-Mineralogical Characterization of Magnetic Materials from Magnetic Soils of the Southern Espinhaço Mountain Chain and of the Upper Jequitinhonha Valley, State of Minas Gerais, Brazil
Provedor de dados: 90
Autores: Silva,Alexandre Christófaro; Souza,Solange de; Fabris,José Domingos; Barbosa,Maurício Soares; Barral,Uidemar Morais; Costa,Roberto Vial.
ABSTRACT In the Southern Espinhaço Mountain Chain and in the Upper Jequitinhonha Valley, magnetic soils, in different pedogenetic stages, are found to be forming over intrusions of basic lithology. The essential chemical and mineralogical properties of samples from magnetic soil profiles from those two physiographic environments in the state of Minas Gerais, Brazil, are reported. Three of the pedons (Rhodic Kandiustox – RKox, Rhodic Haplustox – RHox, and Typic Argiustoll - TAoll) were identified as being indeed developed over basic rocks; the fourth pedon (Typic Haplustox - THox) is currently forming on an acidic rock. Particle size and routine chemical analyses were performed on samples from all horizons of the four selected soil profiles. For a deeper...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Iron oxides; X ray diffractometry; Mössbauer spectroscopy; Scanning electron microscopy; Energy dispersive spectroscopy.
Ano: 2017
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832017000100305

Validation of a Standard Operating Procedure (SOP) for Forensic Soils Investigation in Brazil
Provedor de dados: 90
Autores: Testoni,Samara Alves; Melo,Vander Freitas; Dawson,Lorna Anne; Salvador,Fábio Augusto da Silva; Kunii,Paulo Akira.
ABSTRACT Soil traces are useful as forensic evidence due to their potential to transfer and adhere to different types of surfaces on a range of objects or persons. Several works have been developed in forensic soils, under different analytical approaches. However, in Brazil, only the researches from the Group of the Federal University of Paraná have developed works with soils under a forensic approach. Focus has been given on the sequential chemical analyses and mineralogical techniques once they presented a large potential to discriminate soil samples, even that originated from the same bedrock. In this way, this work aimed to test a Standard Operating Procedure (SOP) for forensic soil sampling and an analytical protocol in Brazil between the academy and...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Forensic science; Soil evidence; Sequential chemical analysis; Gibbsite; Iron oxides.
Ano: 2019
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832019000100410

Genesis and classification of Oxisols in a highland toposequence of the upper Jequitinhonha Valley (MG)
Provedor de dados: 90
Autores: Ferreira,Celmo Aparecido; Silva,Alexandre Christófaro; Torrado,Pablo Vidal; Rocha,Welington Willian.
The Brazilian System of Soil Classification (SiBCS) is a taxonomic system, open and in permanent construction, as new knowledge on Brazilian soils is obtained. The objective of this study was to characterize the chemical, physical, morphological, micro-morphological and mineralogical properties of four pedons of Oxisols in a highland toposequence in the upper Jequitinhonha Valley, emphasizing aspects of their genesis, classification and landscape development. The pedons occupy the following slope positions: summit - Red Oxisol (LV), mid slope (upper third) - Yellow-Red Oxisol (LVA), lower slope (middle third)- Yellow Oxisol (LA) and bottom of the valley (lowest third) - "Gray Oxisol" ("LAC"). These pedons were described and sampled for characterization in...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Soil color; Iron oxides; Soil classification; Pale Oxisol.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832010000100020

Reversibility of the Hardening Process of Plinthite and Petroplinthite in Soils of the Araguaia River Floodplain under Different Treatments
Provedor de dados: 90
Autores: Martins,Angélica Pires Batista; Santos,Glenio Guimarães; Oliveira,Virlei Álvaro de; Maranhão,Deyvid Diego Carvalho; Collier,Leonardo Santos.
ABSTRACT Although ferruginous materials occur frequently in soils of tropical regions, information about the reversal of the hardening process of these materials is scarce. This study assessed the influence of different chemical treatments and periods of immersion on the reversibility of the hardening process of plinthite and petroplinthite in soils of the Araguaia River plain. Soil samples were collected from the plinthic horizons in 0.10 m high and 0.15 m diameter PVC cylinders and divided into subsamples with a rock hammer. Homogeneous petroplinthite samples were also collected and broken into subsamples with a rock hammer. The plinthite and petroplinthite subsamples were subjected to five immersion treatments: distilled water, calcium carbonate...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Dispersion; Deterioration of structural stability; Hardness; Reagents; Iron oxides.
Ano: 2018
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832018000100307

Cristallochemical characterization of synthetic Zn-substituted maghemites (g-Fe2-xZn xO3)
Provedor de dados: 90
Autores: Batista,Marcelo Augusto; Costa,Antonio Carlos Saraiva da; Souza Junior,Ivan Granemann de; Bigham,Jerry Marshal.
Maghemite (g-Fe2O3) is the most usually found ferrimagnetic oxide in red basalt-derived soils. The variable degrees of ionic substitution of Fe3+ for different metals (e.g. Ti4+, Al3+, Mg2+, Zn2+, and Mn2+) and non-metals in the maghemite structure influence some cristallochemical features of this iron oxide. In this study, synthetic Zn-substituted maghemites were prepared by co-precipitation in alkaline aqueous media of FeSO4.7H2O with increasing amounts of ZnSO4.7H2O to obtain the following sequence of Fe3+ for Zn2+ substitutions: 0.0, 0.025, 0.05, 0.10, 0.15, 0.20, and 0.30 mol mol-1. The objective of this work was to evaluate the cristallochemical alterations of synthetic Zn-substituted maghemites. The dark black synthetic precipitated material was...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Iron oxides; X ray diffraction; Mass-specific magnetic susceptibility; Specific surface area; Isomorphic substitution.
Ano: 2008
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832008000200011

Mineralogy of the clay fraction of Alfisols in two slope curvatures: III - spatial variability
Provedor de dados: 90
Autores: Camargo,Livia Arantes; Marques Júnior,José; Pereira,Gener Tadeu.
A good knowledge of the spatial distribution of clay minerals in the landscape facilitates the understanding of the influence of relief on the content and crystallographic attributes of soil minerals such as goethite, hematite, kaolinite and gibbsite. This study aimed at describing the relationships between the mineral properties of the clay fraction and landscape shapes by determining the mineral properties of goethite, hematite, kaolinite and gibbsite, and assessing their dependence and spatial variability, in two slope curvatures. To this end, two 100 × 100 m grids were used to establish a total of 121 regularly spaced georeferenced sampling nodes 10 m apart. Samples were collected from the layer 0.0-0.2 m and analysed for iron oxides, and kaolinite and...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Iron oxides; Kaolinite; Gibbsite; Goethite; Hematite; Relief.
Ano: 2013
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832013000200001

Mineralogy, magnetic susceptibility and geochemistry of Fe-rich Oxisols developed from several parent materials
Provedor de dados: 63
Autores: Camêlo,Danilo de Lima; Ker,João Carlos; Fontes,Maurício Paulo Ferreira; Costa,Antonio Carlos Saraiva da; Corrêa,Marcelo Metri; Leopold,Matthias.
ABSTRACT: Fe-rich Oxisols on mafic rocks in Brazil generally have high magnetic susceptibility with high contents of some trace elements. These are taxonomically similar soils; however, differences in magnetic and geochemical properties may affect agricultural or environmental usability and subsequent management. This study investigated the pedogenesis of Fe-rich Oxisols from various parent materials and evaluated the lithogenetic influence on magnetic susceptibility and trace elements contents. Soil samples were collected from Bw horizons in 13 Rhodic Oxisols and a Typic Oxisol developed from several parent materials in Minas Gerais State, Brazil. Soils were analyzed by X-ray diffractometry (XRD) and magnetometry. Soil chemical analyses consisted of...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Magnetic soils; Iron oxides; Ferrimagnetic minerals; Trace elements; Mafic rocks.
Ano: 2018
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162018000500410

Adsorption of P and forms of iron in no-tillage areas in the ‘Cerrado’ biome
Provedor de dados: 1
Autores: Pereira, Marcos Gervasio; Guareschi, Roni Fernandes; Perin, Adriano.
The objective of this study was to evaluate the forms of iron extracted as sodium dithionite-citrate-bicarbonate (Fed), acid ammonium oxalate (Feo) and sodium pyrophosphate (Fep) and the relationship between these variables and the total organic carbon content and maximum adsorption capacity of P (MACP). The areas selected for this study had been using a no-tillage system (NTS) for varying periods of time: 3 years (NTS3), 15 years (NTS15) and 20 years (NTS20). These areas were compared with an area of native ‘Cerrado’ (CE) and a pasture area planted with Brachiaria decumbens (PA). The soil of the areas studied was classified as dystrophic oxisol. In each area, samples were collected at 0–5 cm and 5–10 cm. A correlation was observed between the C content...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Ciências Agrárias - Agronomia - Ciência do Solo soil organic matter; Pasture; Iron oxides; Oxisol Fertilidade do Solo soil organic matter; Pasture; Iron oxides; Oxisol.
Ano: 2014
URL: http://periodicos.uem.br/ojs/index.php/ActaSciAgron/article/view/17686