The Structure of Rapidly Solidified Powders of Ni3Al and Ni3 Al + B + Ti

1983 ◽  
Vol 28 ◽  
Author(s):  
I. Baker ◽  
F. Ichishita ◽  
E.M. Schulson
Keyword(s):  
Particle Size ◽  
Rapid Solidification ◽  
Solidification Rate ◽  
Dendritic Structure ◽  
Arithmetic Mean ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
X Ray ◽  
Log Normal ◽  
Rapidly Solidified

ABSTRACTPowders of stoichiometric Ni3Al and Ni3Al containing boron and titanium were produced by rapid solidification rate (RSR) processing. Most particles were found to be spherical; some had skins and some contained holes. Fractured particles were found, indicating possible brittleness. Particle size distributions were log-normal with an arithmetic mean particle size of 23.5μm. Both alloys exhibited a dendritic structure in which compositional differences were present. In addition, stoichiometric Ni3Al contained interdendritic lamellae. X-ray diffractometry indicated that the powders were only partially ordered.

scholarly journals X-Ray Dynamical Diffraction in Powder Samples with Time-Dependent Particle Size Distributions - ADDENDUM

MRS Advances ◽  
2020 ◽  
Vol 5 (29-30) ◽  
pp. 1623-1623
Author(s):  
Adriana Valério ◽  
Sérgio L. Morelhão ◽  
Alex J. Freitas Cabral ◽  
Márcio M. Soares ◽  
Cláudio M. R. Remédios
Keyword(s):  
Particle Size ◽  
Time Dependent ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Dynamical Diffraction ◽  
X Ray ◽  
Powder Samples

Phase and Particle Size Analysis of SnO2 Nanomaterials

2015 ◽  
Vol 1109 ◽  
pp. 314-318
Author(s):  
Nor Diyana Abdul Aziz ◽  
Kelimah Elong ◽  
Norlida Kamarulzaman
Keyword(s):  
Particle Size ◽  
Particle Size Analysis ◽  
Annealed Sample ◽  
Degree Of Crystallinity ◽  
Size Analysis ◽  
Size Distributions ◽  
X Ray Diffraction ◽  
Particle Size Distributions ◽  
X Ray ◽  
Particle Sizer

Tin Oxide (SnO2) is a metal oxide which has many applications in industry. In this study, SnO2 powders were synthesized by a self-propagating combustion (SPC) method. The product was annealed at 800 °C for 12 and 24 h before characterizing with X-Ray Diffraction (XRD) for phase studies. X-Ray Diffraction results showed that both samples are pure of tetragonal structure with space group P42/mnm. The sample annealed at a longer period, that is, 24 h, shows a higher degree of crystallinity compared to the 12 h annealed sample. It also shows a smaller full width at half maximum (FWHM), indicating larger crystallite size for the 24 h annealed sample. The particle size analysis reveals that there are two groups of particle size distributions for both samples. SEM results give values that are different from the particle sizer results due to the different nature of the measurement methods.

Textural properties of regoliths on vegetated steep slopes in upland regions, Scotland

1986 ◽  
Vol 77 (3) ◽  
pp. 241-250 ◽  
Author(s):  
J. L. Innes
Keyword(s):  
Particle Size ◽  
Early Stage ◽  
Probability Distributions ◽  
Textural Properties ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Normal Probability ◽  
Log Normal ◽  
Steep Slopes

ABSTRACTThe textural properties of many sediments provide a good indication of their provenance, but surprisingly little information is available on the transitional stages between the breakdown of a rock and the incorporation of the material into a fluvial sediment. These transitional stages are important as certain fractions (particularly the finer ones) may be selectively removed. Regoliths developed on steep slopes represent an early stage in the debris cascade and they are here examined in detail to assess the role of parent lithology on the textural properties of the regolith. There are substantial variations between lithologies, although the majority of regoliths are dominated by coarser fractions and are poorly sorted. Most particle size distributions show some degree of fit to both log-normal probability distributions and Rosin distributions. Differences from these can be ascribed to the processes operating on steep slopes, particularly the influx of sand- and silt-sized material by colluvial processes and the removal of clay-sized material by leaching. The regoliths form a distinct facies type which may be recognisable in the geological record.

scholarly journals Eight-year variations in atmospheric radiocesium in Fukushima City

2021 ◽  
Author(s):  
Akira Watanabe ◽  
Mizuo Kajino ◽  
Kazuhiko Ninomiya ◽  
Yoshitaka Nagahashi ◽  
Atsushi Shinohara
Keyword(s):  
Particle Size ◽  
Numerical Model ◽  
Causal Relationship ◽  
Seasonal Variations ◽  
Fluorescence Analysis ◽  
Terrestrial Ecosystems ◽  
Nuclear Accident ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
X Ray

Abstract. After the Fukushima nuclear accident, atmospheric 134Cs and 137Cs measurements were taken in Fukushima city for eight years, from March 2011 to March 2019. The surface air concentrations and deposition of radio-Cs were high in winter and low in summer; these trends are the opposite of those observed in a contaminated forest area. The half-lives of 137Cs in the concentrations and deposition before 2015 (275 d and 1.11 y) were significantly shorter than those after 2015 (756 d and 4.69 y). The dissolved fractions of precipitation were larger than the particulate fractions before 2015, but the particulate fractions were larger after 2016. The half-lives of 137Cs in the concentrations and deposition were shorter before 2015, probably because the dissolved radio-Cs was discharged from the local terrestrial ecosystems more rapidly than the particulate radio-Cs. X-ray fluorescence analysis suggested that biotite may have played a key role in the environmental behavior of particulate forms of radio-Cs after 2014. However, the causal relationship between the seasonal variations in particle size distributions and the possible sources of particles is not yet fully understood. The current study also proposes a method of evaluating the consistency of a numerical model for radio-Cs resuspension and suggests that improvements to the model are necessary.

Application of Proton Induced X-Ray Emission Analysis to the St. Louis Regional Air Pollution Study

1974 ◽  
Vol 18 ◽  
pp. 588-597
Author(s):  
R. Akselsson ◽  
C. Orsini ◽  
D. L. Meinert ◽  
T. B. Johansson ◽  
R. E. Van Grieken ◽  
...  
Keyword(s):  
Air Pollution ◽  
Particle Size ◽  
Sampling Period ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Emission Analysis ◽  
X Ray ◽  
Particle Size Fractions ◽  
Pollution Study ◽  
Time Variations

AbstractThe St. Louis aerosol was sampled during the period 16-22 August 1973 simultaneously at two locations using cascade impactors for sequential 12-hour samples. The six particle size fractions of each sampling were individually analyzed using PIXE for elements from S to Br and beyond and for heavy elements including Pb which permitted time variations of concentrations and particle size distributions to be followed and related to meteorological changes during the sampling period. In addition, the data were compared with average levels of the elements in coastal north Florida and maritime Bermuda as well as at a third St. Louis site. From this it appeared that some of the concentrations in St. Louis were at natural levels whereas others appeared to be higher and linked to air pollution sources. These relationships and others in this study may lead to criteria for distinguishing between pollutants and natural background in urban aerosols.

DETERMINATION OF ELEMENT CONCENTRATION AND PARTICLE SIZE DISTRIBUTION IN BEIJING URBAN ATMOSPHERIC AEROSOL

1992 ◽  
Vol 02 (04) ◽  
pp. 637-644 ◽  
Author(s):  
GUANGHUA ZHU ◽  
XINFU WANG ◽  
XINYIN SHEN
Keyword(s):  
Particle Size ◽  
Atmospheric Aerosol ◽  
Element Concentration ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Retention Models ◽  
Elemental Concentrations ◽  
Log Normal ◽  
Least Squares Minimization

The atmospheric aerosol samples are collected in Beijing using a ten-stage cascade impactor sampler, and the elemental concentrations are analyzed by the PIXE analytical method. The parameters of particle size distributions are determined by the use of log-normal plots and the least-squares minimization. From these parameters the total amount of deposit in a day at the naso-pharyngeal, tracheo-bronchial and pulmonary are evaluated based on the deposition and retention models.

Textured Coatings from Colloidal Suspensions of Faceted Oxide Microcrystals

1992 ◽  
Vol 286 ◽  
Author(s):  
Gregg.W. Steadman ◽  
J. R. Brewster ◽  
J. D. Budai ◽  
L. A. Boatner
Keyword(s):  
Particle Size ◽  
Colloidal Suspensions ◽  
Fiber Texture ◽  
Preferred Orientation ◽  
Morphological Properties ◽  
Size Distributions ◽  
X Ray Diffraction ◽  
Particle Size Distributions ◽  
X Ray ◽  
Flat Substrate

ABSTRACTThe morphological properties of cubic, faceted MgO microcrystals have been exploited in the formation of textured coatings. Coatings exhibiting a <100> “fiber” texture were formed by centrifugal sedimentation of colloidal suspensions onto a flat substrate. A decrease in the degree of preferred orientation in the coatings with increasing areal coverage of the particles was quantified for several particle-size distributions by using x-ray diffraction. Novel methods for the deposition of particles exhibiting an in-plane preferred orientation in addition to fiber texture have been investigated.

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