scholarly journals Smectite in weathered hyaloclastite of the Shakotan Peninsula, Hokkaido, Japan: significance of clay mineralogy in engineering geology

2000 ◽  
Vol 22 ◽  
Author(s):  
Tetsuro Yoneda ◽  
Ganesh P. Dhakal ◽  
Katsuhiko Kaneko ◽  
Iwao Nakajima
Keyword(s):  
Rock Mass ◽  
Clay Mineralogy ◽  
Volcanic Glass ◽  
Optical Microscope ◽  
Engineering Properties ◽  
X Ray ◽  
Bay Area ◽  
Transmission Electron ◽  
Compositional Field ◽  
Electron Probe Microanalyser

The occurrence and chemical composition of smectite in hyaloclastite from the Toyohama rock fall site of 10 February 1996 and the Oshoro Bay area were examined by using optical microscope, X-ray diffractometer, electron probe microanalyser and analytical transmission electron microscope. Frequently, smectite occurs as fillings and linings of pores in various forms, and sporadically as the replacement of volcanic glass in hyaloclastite. The analytical results show that smectite is of dioctahedral and Fe-rich type. Its compositional field varies extensively between montmorillonite and nontronite. Moreover, interlayer cations of smectite vary intensively in relation with the type of weathering in hyaloclastite. Na-smectite occurs characteristically in discoloured hyaloclastite affected by superficial weathering, whereas Ca- and K-smectite occurs dominantly in the hyaloclastite collected from the inner part of the rock mass. These features of smectite in hyaloclastite can be attributed to its formational and weathering environments. Mineralogical characterisation of hyaloclastite provides detailed information on engineering properties of this type of rock mass and rock materials.

scholarly journals Facile and Scalable Synthesis and Self-Assembly of Chitosan Tartaric Sodium

Polymers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 69
Author(s):  
Sixuan Wei ◽  
Rujie Peng ◽  
Shilong Bian ◽  
Wei Han ◽  
Biao Xiao ◽  
...  
Keyword(s):  
Self Assembly ◽  
Optical Microscope ◽  
Solvent Evaporation ◽  
Resonance Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Evaporation Temperature ◽  
Transmission Electron ◽  
Naoh Solution ◽  
Scalable Synthesis

Chitosan-based nanostructures have been widely applied in biomineralization and biosensors owing to its polycationic properties. The creation of chitosan nanostructures with controllable morphology is highly desirable, but has met with limited success yet. Here, we report that nanostructured chitosan tartaric sodium (CS-TA-Na) is simply synthesized in large amounts from chitosan tartaric ester (CS-TA) hydrolyzed by NaOH solution, while the CS-TA is obtained by dehydration-caused crystallization. The structures and self-assembly properties of CS-TA-Na are carefully characterized by Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (1H-NMR), X-ray diffraction (XRD), differential scanning calorimeter (DSC), transmission electron microscopy (TEM), a scanning electron microscope (SEM) and a polarizing optical microscope (POM). As a result, the acquired nanostructured CS-TA-Na, which is dispersed in an aqueous solution 20–50 nm in length and 10–15 nm in width, shows both the features of carboxyl and amino functional groups. Moreover, morphology regulation of the CS-TA-Na nanostructures can be easily achieved by adjusting the solvent evaporation temperature. When the evaporation temperature is increased from 4 °C to 60 °C, CS-TA-Na nanorods and nanosheets are obtained on the substrates, respectively. As far as we know, this is the first report on using a simple solvent evaporation method to prepare CS-TA-Na nanocrystals with controllable morphologies.

Development of a High-Speed Optical Microscope Auto-Focus Control System for EPMA

1996 ◽  
Vol 54 ◽  
pp. 442-443
Author(s):  
S. Notoya ◽  
M. Saito ◽  
M. Matsuya ◽  
T. Ishii ◽  
K. Murakami ◽  
...  
Keyword(s):  
Control System ◽  
High Speed ◽  
Optical Microscope ◽  
X Rays ◽  
Depth Of Focus ◽  
X Ray ◽  
Simultaneous Acquisition ◽  
New Development ◽  
Electron Probe Microanalyser ◽  
Dimensional Element

This paper reports the new development of an optical microscope automatic focus control system (OMAFD) for the JXA-8800/8900 series Electron Probe Microanalyser (EPMA). In recent years, a method called “wide area mapping” has been increasingly used with EPMA for measurement of X-rays by moving the specimen to obtain 2-dimensional element distributions over large analysis areas. In mapping, the simultaneous acquisition of multiple elements is required. Using an optical microscope, which has a very small (about ±1 μm) depth of focus, the specimen surface needs to be vertically adjusted to the Rowland circle of a wavelength dispersive X-ray spectrometer. Even with flat specimens, actual analysis points often show some inclination. Specimens are often inclined accidentally during sample preparation and mounting. Moreover, requirements of specimen analysis with curved or irregular surfaces have been increasing.

Electron Microscopy and X-Ray Microanalysis in Forensic Science

1973 ◽  
Vol 56 (4) ◽  
pp. 930-943
Author(s):  
John L Brown ◽  
James W Johnson
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Chemical Elements ◽  
Optical Microscope ◽  
Forensic Analysis ◽  
Depth Of Focus ◽  
Crystalline Materials ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Abstract The optical microscope has long been an important tool in forensic analysis for the comparison of firearms markings and the examination and identification of other minute bits of evidence. The electron microscope permits the examination of even smaller details and offers analytical capabilities unique to the type of instrument used. The transmission electron microscope can be used to identify very small amounts of crystalline materials through the process of electron diffraction. The scanning electron microscope can frequently supersede the optical microscope because of its superior depth of focus and range of magnification. When it is equipped with an energy dispersive X-ray analyzer, most of the chemical elements in a sample can be determined. Applications of these instruments have provided some interesting and instructive results in forensic analysis.

scholarly journals Study on Growth Mechanism of Cu Nanowires and Its Application as Transparent Conducting Electrode

2019 ◽  
Vol 19 (1) ◽  
pp. 160
Author(s):  
Dedi Mardiansyah ◽  
Kuwat Triyana ◽  
Harsojo Harsojo
Keyword(s):  
Electron Microscopy ◽  
Growth Mechanism ◽  
Optical Microscope ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cu Nanowires ◽  
Transparent Conducting Electrode ◽  
Transparent Conducting ◽  
Conducting Electrode ◽  
Transmission Electron

Cu nanowires (CuNWs) were synthesized in an aqueous solution at low temperature using ethylenediamine (EDA) as a capping agent and hydrazine as a reducing agent. This study investigated the growth of mechanism CuNWs and fabricated the transparent conducting electrode. For the growth mechanism of CuNWs, the study was conducted with an optical microscope, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The performance of the transparent conducting electrode was studied with UV-Vis spectrometer and IV meters. CuNWs growth from Cu nanoparticles (CuNPs) in the solution. Transparent conducting electrode gave a sheet resistance of 48.8 Ohm/sq and the transmittance of 52.63%. The understanding of the growing mechanism of Cu nanowires is important for the development of CuNWs for alternative application as a transparent conducting electrode.

Mechanism of Work Hardening of Mn13 after Asynchronous Cold Rolling

2011 ◽  
Vol 117-119 ◽  
pp. 118-121
Author(s):  
Yan Feng Wang ◽  
Chang Ming Qiu ◽  
Hong Chan Sun
Keyword(s):  
Electron Microscope ◽  
Electron Diffraction ◽  
Cold Rolling ◽  
Electron Diffraction Pattern ◽  
Work Hardening ◽  
Optical Microscope ◽  
Theory And Practice ◽  
X Ray ◽  
Photographic Camera ◽  
Transmission Electron

The hardness of Mn13 can increase if taking asynchronous cold rolling technique .The mechanism of work hardening after asynchronous cold rolling is analyzed in depth by studying the microstructure and electron diffraction pattern with optical microscope, transmission electron microscope and X-ray electron diffract photographic camera. The research will make a contribution to theory and practice of Mn13.

Preparation and tribological properties of BN/calcium borate nanocomposites as additive in lubricating oil

2018 ◽  
Vol 70 (1) ◽  
pp. 105-114 ◽  
Author(s):  
Yanfei Yang ◽  
Xiaobo Wang ◽  
Sen Mei ◽  
Xing Zhu ◽  
Shiqiang Chen ◽  
...  
Keyword(s):  
Tribological Properties ◽  
Optical Microscope ◽  
Lubricating Oil ◽  
Core Shell ◽  
Calcium Borate ◽  
Wear Area ◽  
Content Type ◽  
X Ray ◽  
Friction Tester ◽  
Transmission Electron

Purpose The purpose of this paper is to investigate the tribological performance and mechanisms of BN/calcium borate nanocomposites (BCBNs) as additives in lubricating oil. Design/methodology/approach BCBNs were prepared by heterogeneous deposition method. And the morphology and structure of samples were analysed by transmission electron microscopy, Fourier transform infrared spectra and X-ray powder diffraction pattern. The maximum non-seizure load (PB) of samples was tested using four-ball friction tester. The average friction coefficients and wear tracks were obtained. In addition, tribological mechanism was also investigated using optical microscope, energy dispersive spectroscopy and X-ray photoelectron spectroscope. Findings It was found that the nanocomposites present core-shell nanostructure with the thickness of shell around 12 nm and the diameter of particles 100-200 nm, and tribological tests indicate that the PB value of BCBNs was increased by 113 per cent, whereas the average friction coefficient was decreased by 23.6 per cent and the bloom’s wear area was also decreased by 25.2 per cent. Originality/value This paper involves investigation on tribological properties and mechanism of the BCBNs with core-shell structure.

scholarly journals Effects of fines content on hydraulic conductivity and morphology of laterite soil as hydraulic barrier

2018 ◽  
Vol 34 ◽  
pp. 01005 ◽  
Author(s):  
Yamusa Bello Yamusa ◽  
Nor Zurairahetty Mohd Yunus ◽  
Kamarudin Ahmad ◽  
Norhan Abd Rahman ◽  
Radzuan Sa’ari
Keyword(s):  
Clay Mineralogy ◽  
Dry Weight ◽  
Engineering Properties ◽  
Molecular Characteristics ◽  
Natural Soil ◽  
Laterite Soil ◽  
Liner Material ◽  
Fines Content ◽  
Landfill Liner ◽  
X Ray

Laterite soil was investigated to find out the effects of fines content and to identify the micro-structural and molecular characteristics to evaluate its potentiality as a compacted soil landfill liner material. Tests were carried out on natural soil and reconstituted soil by dry weight of soil samples to determine the physical and engineering properties of the soil. All tests were carried out on the samples by adopting the British Standard 1377:1990. The possible mechanisms that contributed to the clay mineralogy were analyzed using spectroscopic and microscopic techniques such as field emission scanning electron microscopy (FESEM), energy-dispersive X-ray (EDX) and X-ray diffractometry (XRD). The laterite soil was found to contain kaolinite as the major clay minerals. A minimum of 50% fines content of laterite soil met the required result for hydraulic barriers in waste containment facilities.

Contrasted mineralogical composition of the laterite cover on serpentinites of Nkamouna-Kongo, southeast Cameroon

Clay Minerals ◽  
2009 ◽  
Vol 44 (2) ◽  
pp. 221-237 ◽  
Author(s):  
R. Yongue–Fouateu ◽  
M. Yemefack ◽  
A. S. L. Wouatong ◽  
P. D. Ndjigui ◽  
P. Bilong
Keyword(s):  
Electron Microscopy ◽  
Microprobe Analysis ◽  
Clay Mineralogy ◽  
Mineralogical Composition ◽  
Ultramafic Rocks ◽  
Flow Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Close Relationship

AbstractFour drill cores along a lateritic hill in Nkamouna-Kongo (southeast Cameroon) were studied using microprobe analysis, X-ray diffraction, scanning electron microscopy, transmission electron microscopy and infrared spectroscopy. The main objective of the study was to investigate the occurrence of clay silicates while evaluating the Ni-Co content of the laterite for potential mineral exploitation. The thick lateritic profiles (>40 m deep) developed on serpentinized ultramafic rocks have an Fe-rich clayey fraction, with goethite as the main mineralogical constituent and secondary quartz and relicts of magnetite-maghemite as accessory minerals. Silicate clays are less abundant and occur mainly towards the top of the profiles. At the summit of the interfluve, kaolinite and some gibbsite are associated with goethite. Along the slopes, at the bottom of profiles, the weathered bedrock shows the presence of smectite (Fe-beidellite) and kaolinite, probably due to slower water-flow conditions. Towards the top of the profile in the lower clay, ferruginous and upper clay horizons, only kaolinite remains with gibbsite, after the leaching of silica and soluble cations following repeated remobilization-recrystallization processes. At the summit, where the downward movement of water is rapid, no smectite was identified. As a whole, the mineralogical composition of the material varies in close relationship with the drainage, leading to a contrasted clay mineralogy marked by the presence of Fe-beidellite and kaolinite at the bottom, and that of kaolinite and gibbsite at the summit of the profiles.

Growth of crack-free GaN on AlN quantum dots on Si(111)substrates by MOCVD

2003 ◽  
Vol 798 ◽  
Author(s):  
W. H. Sun ◽  
J. L. Chen ◽  
L. S. Wang ◽  
S. J. Chua
Keyword(s):  
Quantum Dots ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Optical Microscope ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Transmission Electron ◽  
Pressure Chemical ◽  
Aln Buffer

AlN self-assembled quantum dots (QDs) with high density of ∼ 4.4 × 1010/cm2 on Si(111) substrates have been grown by low-pressure chemical vapor deposition under a very low V/III ratio of 350. We found that using AlN-QD/AlN buffer two-inch GaN epilayers without cracks were grown, indicating the underlying quantum dots play a crucial role in relaxing the stain of GaN epilayer. The quality and morphology were investigated by atom force microscopy, transmission electron microscopy, X-ray diffraction and optical microscope.

Niobium-Alloyed Steel Treated by Quenching-Partitioning-Tempering

2014 ◽  
Vol 528 ◽  
pp. 149-152
Author(s):  
Hua Zheng ◽  
Kai Ming Wu ◽  
S.F. Sun ◽  
G.W. Hu
Keyword(s):  
Hardness Test ◽  
Optical Microscope ◽  
Medium Carbon Steel ◽  
Test Results ◽  
X Ray Diffraction ◽  
Medium Carbon ◽  
X Ray ◽  
Fine Grained ◽  
Recent Interest ◽  
Transmission Electron

Given the strong recent interest in quenching-partitioning-tempering processed steels, the Niobium-alloyed medium carbon steel was investigated here. The microstructural observations and hardness were analyzed by optical microscope, transmission electron microscope, X-ray diffraction and hardness test. Results show that when quenched at 210°C and partitioned at 450°C, the quenching partitioning-tempering process leads to ultra fine-grained microstructures of martensite, retained austenite and carbides. And the microstructure and hardness changed differently with the increase of partitioned time.

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