Quartz surface microtextures and grain-size characteristics of Quaternary sediments in the Porcupine Strand area of coastal Labrador, Newfoundland, Canada

1983 ◽  
Vol 20 (3) ◽  
pp. 377-387 ◽  
Author(s):  
R. J. Rogerson ◽  
H. M. Hudson
Keyword(s):  
Grain Size ◽  
Distribution Data ◽  
Quartz Surface ◽  
Quaternary Sediments ◽  
Multivariate Statistical ◽  
Surface Textures ◽  
Systematic Fashion ◽  
Statistical Pattern ◽  
Quartz Grains ◽  
Scanning Electron

Sand-sized quartz grains from five Quaternary environments on the coast of Labrador were scrutinized under a scanning electron microscope. Various surface textural characteristics defined in previous literature were noted and "counted" in a systematic fashion. Multivariate statistical analysis of the data reveals that certain groups of surface textures provide for significant environmental identification, but no single surface texture is unique to any one environment. Absolute recognition of a particular environment from the presence of "diagenetic" features on several grains is not recommended for areas such as this. Yet the statistical pattern of scores for some features results in a position of individual samples and groups similar to the patterns obtained from the analysis of grain-size distribution data. The glacial environment appears to be no harder to define than most others in this type of analysis.

Quartz grain characteristics of the late Pleistocene hard clay in the Yangtze River delta and implications for sedimentary environment and provenance

2020 ◽  
Vol 97 ◽  
pp. 199-215
Author(s):  
Chao Wu ◽  
Peng Qian ◽  
Xiangmin Zheng ◽  
Limin Zhou ◽  
Hui Wang ◽  
...  
Keyword(s):  
Grain Size ◽  
Late Pleistocene ◽  
Yangtze River ◽  
Yangtze River Delta ◽  
River Delta ◽  
The Yangtze River ◽  
The Yrd ◽  
The Yangtze River Delta ◽  
Quartz Grains ◽  
Scanning Electron

AbstractThe sedimentologic fingerprinting in detrital deposit is vital to reconstruct sedimentary environments and discriminate sources. In this study, grain size and microtextural characteristics of quartz from the late Pleistocene hard clay in the Yangtze River delta (YRD) were analyzed by using a laser particle size analyzer and a scanning electron microscope. Subaqueous quartz from the Yangtze River and Yellow River sediments and eolian quartz from the Chinese Loess Plateau loess were also analyzed by scanning electron microscopy to obtain the microtextural characteristics. Quartz grains of the hard clay were characterized by poor sorting, fine skew, bimodal grain-size distributions, and numerous eolian microtextures. The comparison of the quartz grain characteristics of the hard clay with these in eolian loess indicated that the hard clay belonged to an eolian deposition. Moreover, the fine quartz grains of the hard clay were dominated by eolian microtextural characteristics, representing long-distance transportation. The coarse quartz grains of the hard clay exhibited more subaqueous microtextural characteristics, which indicated that the coarse fraction of the hard clay was derived from the proximal source regions in the YRD. The determination of buried eolian deposition with multiple sources in the YRD implies a southward westerly jet stream, strengthened eolian dust transportation, and extensive aridification in the YRD due to the increased Northern Hemisphere ice sheets in Marine Oxygen Isotope Stage 2.

scholarly journals The Domain and Microstructure of Resin-Bonded Magnets

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2849
Author(s):  
Marcin Jan Dośpiał
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Grain Size ◽  
Size Distribution ◽  
Domain Structure ◽  
Grain Size Distribution ◽  
Exchange Interactions ◽  
Force Microscopy ◽  
Transmission Electron ◽  
Scanning Electron

This paper presents domain and structure studies of bonded magnets made from nanocrystalline Nd-(Fe, Co)-B powder. The structure studies were investigated using scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), Mössbauer spectroscopy and X-ray diffractometry. On the basis of performed qualitative and quantitative phase composition studies, it was found that investigated alloy was mainly composed of Nd2(Fe-Co)14B hard magnetic phase (98 vol%) and a small amount of Nd1.1Fe4B4 paramagnetic phase (2 vol%). The best fit of grain size distribution was achieved for the lognormal function. The mean grain size determined from transmission electron microscopy (TEM) images on the basis of grain size distribution and diffraction pattern using the Bragg equation was about ≈130 nm. HRTEM images showed that over-stoichiometric Nd was mainly distributed on the grain boundaries as a thin amorphous border of 2 nm in width. The domain structure was investigated using a scanning electron microscope and metallographic light microscope, respectively, by Bitter and Kerr methods, and by magnetic force microscopy. Domain structure studies revealed that the observed domain structure had a labyrinth shape, which is typically observed in magnets, where strong exchange interactions between grains are present. The analysis of the domain structure in different states of magnetization revealed the dynamics of the reversal magnetization process.

Sintering Process of Nd:YAG Transparent Ceramic

2013 ◽  
Vol 281 ◽  
pp. 475-479
Author(s):  
Bo Wang ◽  
Quan Xi Cao ◽  
Guang Xu ◽  
Sen Tian
Keyword(s):  
Grain Size ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Crystal Structures ◽  
Heating Rate ◽  
Optical Transmittance ◽  
Sintering Process ◽  
X Ray ◽  
Polycrystalline Ceramics ◽  
Scanning Electron

1.0at% Nd:YAG polycrystalline ceramics were sintered at 1420°C, 1500°C, 1600°C and 1730°C respectively by different heating rate (1°C/min and 5°C/min). The crystal structures were indexed by X-ray diffractometer (XRD). The microstructure and the grain size of the samples were characterized by scanning electron microscope (SEM). The optical transmittance spectra of the samples were measured using V-570 UV spectrophotometer. The sintering process of Nd:YAG ceramics and the effect of heating rate on the microstructure of samples have been investigated.

scholarly journals 6. The Nature of Asteroid Surfaces, from Optical Polarimetry

1977 ◽  
Vol 39 ◽  
pp. 243-251 ◽  
Author(s):  
A. Dollfus ◽  
J. E. Geake ◽  
J. C. Mandeville ◽  
B. Zellner
Keyword(s):  
The Body ◽  
Space Weathering ◽  
Carbonaceous Chondrites ◽  
The Moon ◽  
Laboratory Measurements ◽  
Surface Textures ◽  
Lunar Samples ◽  
Dark Material ◽  
Polarization Of Light ◽  
Scanning Electron

Telescopic observations of the polarization of light by asteroids are interpreted on the basis of a systematic polarimetric analysis of terrestrial, meteoritic and lunar samples. Laboratory measurements were made using samples with different surface textures, and scanning electron microscope pictures were used to investigate the influence of microtexture and crystalline structure.It is demonstrated that asteioid surfaces do not accumulate thick regolithic layers of micro-fragments, as do the Moon and Mercury. This is because the majority of debris ejected by impacts are lost, due to the low gravitational escape velocity from these bodies. However, asteroids are not bare rocks, but are coated with a thin layer of adhesive debris. This coating apparently has the composition of the body itself. The fact that there is no indication of significant maturation by space weathering suggests that the dust which coats the surface of asteroids is frequently replaced by further impacts.Asteroids may be classified polarimetrically in several groups: those in group C are made of very dark material and behave like carbonaceous chondrites, or very dark Fe-rich basalts; Those in group S correspond to silicates and stony meteorites. A third group represented by Asteroid 21 Lutetia and 16 Psyche may be metallic.

The Synthesis of Cu0.81Ni0.19 Intermetallics by Mechanical Alloying

2012 ◽  
Vol 496 ◽  
pp. 379-382
Author(s):  
Rui Song Yang ◽  
Ming Tian Li ◽  
Chun Hai Liu ◽  
Xue Jun Cui ◽  
Yong Zhong Jin
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Grain Size ◽  
Mechanical Alloying ◽  
Milling Time ◽  
Elemental Powder ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scherrer Equation ◽  
Scanning Electron

The Cu0.81Ni0.19 has been synthesized directly from elemental powder of nickel and copper by mechanical alloying. The alloyed Cu0.81Ni0.19 alloy powders are prepared by milling of 8h. The grain size calculated by Scherrer equation of the NiCu alloy decreased with the increasing of milling time. The end-product was analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM)

La production de limon sur des terrasses de cryoplanation dans les monts Richardson, Canada

1999 ◽  
Vol 36 (10) ◽  
pp. 1645-1654 ◽  
Author(s):  
I Lamirande ◽  
B Lauriol ◽  
A E Lalonde ◽  
I D Clark
Keyword(s):  
Grain Size ◽  
Size Fraction ◽  
Runoff Water ◽  
Chemical Action ◽  
Intergranular Porosity ◽  
Potential Source ◽  
Petrographic Analyses ◽  
Glacial Time ◽  
Richardson Mountains ◽  
Quartz Grains

The production of silt on cryoplanation terraces in the Richardson Mountains was documented by a sedimentological study. Geochemical, grain-size, and petrographic analyses of the Jurassic Bug Creek sandstone were done. Results show that in the unaltered rock the detrital quartz grains are solidly held by a siliceous cement. In the altered and strongly altered sandstone, there is a marked increase in intergranular porosity and fracturing of the grains. The disaggregation and weathering of the sandstone releases mainly material in the silt-size fraction, with lesser amounts of sand and clay. This material covers the tread of the terraces and constitutes a potential source of loess in glacial time. Runoff water has a PCO2 value two orders of magnitude greater than the atmosphere yet is weakly mineralized, with only amorphous silica approaching saturation. However, the weathering of sandstones is probably accelerated by the chemical action of water which, by attacking the cement that forms the diagenetic overgrowth of the quartz grains, facilitates their release.

Study on the Properties of Doped La in BaBi4Ti4O15 Ceramic

2007 ◽  
Vol 26-28 ◽  
pp. 243-246
Author(s):  
Xing Hua Yang ◽  
Jin Liang Huang ◽  
Xiao Wang ◽  
Chun Wei Cui
Keyword(s):  
Crystal Structure ◽  
Grain Size ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Sintering Temperature ◽  
Solid Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lanthanum Content ◽  
Scanning Electron

BaBi4-xLaxTi4O15 (BBLT) ceramics were prepared by conventional solid phase sintering ceramics processing technology. The crystal structure and the microstructure were detected by X-ray diffraction (XRD) and scanning electron microscope (SEM). The XRD analyses show that La3+ ions doping did not change the crystal structure of BBT ceramics. The sintering temperature increased from 1120°C to 1150°C with increasing Lanthanum content from 0 to 0.5, but it widened the sintering temperature range from 20°C to 50°C and refined the grain size of the BBT ceramic. Additionally, polarization treatment was performed and finally piezoelectric property was measured. As a result, the piezoelectric constant d33 of the 0.1at.% doped BBLT ceramics reached its highest value about 22pc/N at polarizing electric field of 8kV/mm and polarizing temperature of 120°C for 30min.

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