scholarly journals Mineralogical characterization of clay mineral assemblages from Rio de Janeiro pegmatites to identify kaolinite and/or halloysite deposits

Cerâmica ◽  
2020 ◽  
Vol 66 (380) ◽  
pp. 483-495
Author(s):  
V. M. J. Salgado-Campos ◽  
L. C. Bertolino ◽  
F. J. da Silva ◽  
J. C. Mendes
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Chemical Analysis ◽  
Rio De Janeiro ◽  
Mineralogical Characterization ◽  
X Ray ◽  
Mineral Assemblages ◽  
Saprolite Zone ◽  
Scanning Electron

Abstract This study reports the mineralogical characterization of kaolin occurrences in the State of Rio de Janeiro, Brazil, to identify new kaolinite and halloysite deposits. Samples were collected in 10 pegmatites with varying sizes for X-ray diffractometry, chemical analysis by X-ray fluorescence, and scanning electron microscopy studies. The results indicated that the kaolin occurrences were of weathered origin, wherein some places there were occurrences of tubular halloysite. Concerning the regolith stratigraphy, samples located in the saprock zone were found to contain kaolinite and/or halloysite contents from 0 to 10.1%, while those located in the saprolite zone contained kaolinite and/or halloysite contents from 16.3% to 34.9%. Kaolinite and/or halloysite-7Å were formed from plagioclase weathering instead of K-feldspar or mica, and the halloysite-7Å occurrence was related to samples in regions with a higher degree of weathering.

Mineralogical Characterization of Hispano-Moresque Glazes: A µ-Raman and Scanning Electron Microscopy with X-Ray Energy Dispersive Spectrometry (SEM-EDS) Study

2018 ◽  
Vol 24 (3) ◽  
pp. 300-309 ◽  
Author(s):  
Susana Coentro ◽  
Rui C. da Silva ◽  
Cátia Relvas ◽  
Teresa Ferreira ◽  
José Mirão ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Energy Dispersive Spectrometry ◽  
Raw Materials ◽  
Energy Dispersive ◽  
Mineralogical Characterization ◽  
X Ray ◽  
Intermediate Phases ◽  
Scanning Electron

AbstractThis work explores the combination of µ-Raman spectroscopy and scanning electron microscopy with X-ray energy dispersive spectrometry (SEM-EDS) for the study of the glazes in 15th–16th century Hispano-Moresque architectural tiles. These are high lead glazes that can be tin-opacified or transparent, and present five colors: tin-white, cobalt-blue, copper-green, iron-amber, and manganese-brown. They are generally homogenous and mineral inclusions are mostly concentrated in the glaze-ceramic interface. Through SEM-EDS, these inclusions were observed and chemically analyzed, whereas µ-Raman allowed their identification on a molecular level. K-feldspars, wollastonite and diopside were the most common compounds, as well as cassiterite agglomerates that render the glaze opaque. Malayaite was identified in green glazes, and andradite and magnesioferrite in amber glazes. Co–Ni–ferrites were identified in blue glazes, as well as Ni–Fe–olivines. Manganese-brown is the color where most compounds were identified: bustamite, jacobsite, hausmannite, braunite, and kentrolite. Through the µ-Raman analysis of different areas in large inclusions previously observed by SEM, it was possible to identify intermediate phases that illustrate the reaction process that occurs between the color-conferring compounds and the surrounding lead glaze. Furthermore, the obtained results allowed inference of the raw materials and firing temperatures used on the manufacture of these tiles.

scholarly journals Characterization of a Mahamayuri Vidyarajni Sutra excavated in Lu’an, China

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Liu Liu ◽  
Decai Gong ◽  
Zhengquan Yao ◽  
Liangjie Xu ◽  
Zhanyun Zhu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Tang Dynasty ◽  
Optical Microscope ◽  
Lead White ◽  
Scientific Methods ◽  
X Ray ◽  
Micro Raman Spectroscopy ◽  
Scanning Electron

Abstract Historically, sutras played an important role in spreading Buddhist faith and doctrine, and today these remain important records of Buddhist thought and culture. A Mahamayuri Vidyarajni Sutra with polychrome paintings was found inside the cavity on top of the Nanmen Buddhist pagoda, built in the early Tang dynasty (618–627 CE) and located in Anhui Province, China. Textile was found on the preface which is strongly degraded and fragile. Unfortunately, the whole sutra is under severe degradation and is incomplete. Technical analysis based on scientific methods will benefits the conservation of the sutra. Optical microscopy (OM), micro-Raman spectroscopy combined with optical microscope (Raman), scanning electron microscopy in combination with energy dispersive X-ray analysis (SEM–EDS) and Fourier Transform Infrared Spectroscopy (FTIR) were used to characterize the pigment and gilded material, as well as the paper fiber and textile. Pigments such as cinnabar, minium, paratacamite, azurite, lead white were found. Gilded material was identified as gold. A five-heddle warp satin, made of silk, was found as the textile on the preface of the sutra. The sutra’s preface and inner pages were made of paper comprised of bamboo and bark. As a magnificent yet recondite treasure of Buddhism, the sutra was analyzed for a better understanding of the material. A conservation project of the sutra will be scheduled accordingly.

Preliminary Preparation and Characterization Studies of Cellulose from Merbau (Intsia bijuga)

2012 ◽  
Vol 620 ◽  
pp. 314-319
Author(s):  
Nur Amira Mamat Razali ◽  
Fauziah Abdul Aziz ◽  
Saadah Abdul Rahman
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Alkaline Treatment ◽  
Raw Material ◽  
X Ray Diffraction ◽  
X Ray ◽  
Preliminary Preparation ◽  
Characterization Studies ◽  
Scanning Electron

Hardwood is wood from angiosperm trees. The characteristic of hardwood include flowers, endosperm within seeds and the production of fruits that contain the seeds. This paper aims to discuss the preparation and characterization of cellulose obtained from hardwood. The hardwood Merbau (Intsia bijuga) was chosen as raw material in this study. Alkaline treatment and delignification methods were used for the preparation of cellulose. Acid hydrolysis was employed to produce cellulose nanocrystal (CNC). The treated and untreated samples were characterized using x-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). The final product, from both trated and untreated samples were then compared.

Hydrothermal Synthesis and Characterization of BiFeO3 Polyhedral Crystallites

2012 ◽  
Vol 174-177 ◽  
pp. 508-511
Author(s):  
Lin Lin Yang ◽  
Yong Gang Wang ◽  
Yu Jiang Wang ◽  
Xiao Feng Wang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

BiFeO3 polyhedrons had been successfully synthesized via a hydrothermal method. The as-prepared products were characterized by power X-ray diffraction (XRD) pattern, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The possible mechanisms for the formation of BiFeO3 polyhedrons were discussed. Though comparison experiments, it was found that the kind of precursor played a key role on the morphology control of BiFeO3 crystals.

Geochemistry of halloysite-7Å formation from plagioclase in trachyandesite rocks from Limnos Island, Greece

Clay Minerals ◽  
2014 ◽  
Vol 49 (1) ◽  
pp. 75-89 ◽  
Author(s):  
D. Papoulis ◽  
S. Komarneni ◽  
D. Panagiotaras
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Chemical Analysis ◽  
Geochemical Data ◽  
X Ray Diffraction ◽  
Polarizing Microscopy ◽  
X Ray ◽  
Geochemical Evaluation ◽  
Scanning Electron ◽  
Southwest Part

AbstractTrachyandesite rocks, occurring over an area of about 1 km2in the southwest part of Limnos Island, Greece, are altered mainly to halloysite. The samples were collected and analysed by polarizing microscopy, powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and chemical analysis. The alteration of plagioclase to halloysite follows seven discrete stages that are described in detail. The geochemical evaluation of the data shows enrichment of the lightREE(LREE) over heavyREE(HREE) as expressed by the (La/Yb)n ratio. TheΣLREErange from 206.44 to 272.30, while the sum ofHREEvaries from 11.01 to 26.26. The (La/Yb)n ratio ranges from 9.72 to 27.64. Fractionation amongLREEexpressed as (La/Sm)n and between middleREE(MREE) andHREEis shown as (Tb/Yb)n ratios. The most altered rocks close to the fault zone have high (Tb/Yb)n ratios and low (La/Sm)n and Eu/Eu* ratios. Although mineralogy and clay mineral textures indicate hydrothermal genesis of halloysite, the geochemical data are not conclusive due to a secondary weathering effect.

Characterization of a coating for radioprotection, by X-ray diffraction, scanning electron microscopy, and dispersive energy spectroscopy

2022 ◽  
Vol 321 ◽  
pp. 126326
Author(s):  
Gladis Aparecida Galindo Reisemberger de Souza ◽  
Ramón Sigifredo Cortés Paredes ◽  
Frieda Saicla Barros ◽  
Gustavo Bavaresco Sucharski ◽  
Sebastião Ribeiro Junior ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

New perspectives on Nephridiacanthus major (Acanthocephala: Oligacanthorhynchidae) collected from hedgehogs in Iran

2020 ◽  
Vol 94 ◽  
Author(s):  
O.M. Amin ◽  
M. Sharifdini ◽  
R.A. Heckmann ◽  
M. Zarean
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Phylogenetic Analysis ◽  
Chemical Analysis ◽  
Central Asia ◽  
Molecular Profile ◽  
X Ray ◽  
The Family ◽  
First Time ◽  
Scanning Electron

We describe morphological features not previously reported for this old acanthocephalan Nephridiacanthus major (Bremser, 1811 in Westrumb, 1821) Golvan, 1962 first described over 200 years ago. Our specimens were collected from long-eared hedgehog Hemiechinus auritus (Gmelin, 1770) (Erinaceidae) in Iran. We compare the morphometrics of our material with others previously reported from the same host in Iran, Russia, central Asia and Europe. Our specimens had markedly smaller proboscides, proboscis hooks and lemnisci than those reported from Russia and central Asia, but comparable measurements of other structures with specimens previously described from other collections. We document our new observations with scanning electron microscopy features not previously demonstrable by other observers and provide a chemical analysis of proboscis hooks using energy-dispersive X-ray analysis for the first time. The molecular profile of this acanthocephalan, based on 18S rDNA and cox1 genes, was generated for the first time. The phylogenetic analysis showed that N. major is placed in a clade of the family Oligacanthorhynchidae, well separated from the families Moniliformidae and Gigantorhynchidae.

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