Analysis of the Mean Diameters and Particle-Size Distribution in Powders

2010 ◽  
Vol 27 (5-6) ◽  
pp. 158-164 ◽  
Author(s):  
Pedro González-Tello ◽  
Fernando Camacho ◽  
José. M. Vicaria ◽  
Pedro A. González
1994 ◽  
Vol 59 (6) ◽  
pp. 1301-1304
Author(s):  
Jaroslav Nývlt ◽  
Stanislav Žáček

Lead iodide was precipitated by a procedure in which an aqueous solution of potassium iodide at a concentration of 0.03, 0.10 or 0.20 mol l-1 was stirred while an aqueous solution of lead nitrate at one-half concentration was added at a constant rate. The mean size of the PbI2 crystals was determined by evaluating the particle size distribution, which was measured sedimentometrically. The dependence of the mean crystal size on the duration of the experiment exhibited a minimum for any of the concentrations applied. The reason for this is discussed.


Author(s):  
H. Lin ◽  
X. Zhang ◽  
Y. Yang ◽  
X. Wu ◽  
D. Guo

From geologic perspective, understanding the types, abundance, and size distributions of minerals allows us to address what geologic processes have been active on the lunar and planetary surface. The imaging spectrometer which was carried by the Yutu Rover of Chinese Chang’E-3 mission collected the reflectance at four different sites at the height of ~ 1 m, providing a new insight to understand the lunar surface. The mineral composition and Particle Size Distribution (PSD) of these four sites were derived in this study using a Radiative Transfer Model (RTM) and Sparse Unmixing (SU) algorithm. The endmembers used were clinopyroxene, orthopyroxene, olivine, plagioclase and agglutinate collected from the lunar sample spectral dataset in RELAB. The results show that the agglutinate, clinopyroxene and olivine are the dominant minerals around the landing site. In location Node E, the abundance of agglutinate can reach up to 70 %, and the abundances of clinopyroxene and olivine are around 10 %. The mean particle sizes and the deviations of these endmembers were retrieved. PSDs of all these endmembers are close to normal distribution, and differences exist in the mean particle sizes, indicating the difference of space weathering rate of these endmembers.


2004 ◽  
Vol 19 (9) ◽  
pp. 2765-2773 ◽  
Author(s):  
A.J. Kulkarni ◽  
K. Krishnamurthy ◽  
S.P. Deshmukh ◽  
R.S. Mishra

Aging of precipitation hardened alloys results in particle coarsening, which in turn affects the strength. In this study, the effect of particle size distribution on the strength of precipitation-hardened alloys was considered. To better represent real alloys, the particle radii were distributed using the Wagner and Lifshitz and Slyozov (WLS) particle size distribution theory. The dislocation motion was simulated for a range of mean radii and the critical resolved shear stress (CRSS) was calculated in each case. Results were also obtained by simulating the dislocation motion through the same system but with the glide plane populated by equal strength particles, which represent mean radii for each of the aging times. The CRSS value with the WLS particle distribution tends to decrease for lower radii than it does for the mean radius approach. The general trend of the simulation results compares well with the analytical values obtained using the equation for particle shearing and the Orowan equation.


2010 ◽  
Vol 28 (No. 1) ◽  
pp. 36-43
Author(s):  
P. Sladký ◽  
R. Koukol

The hazes of freshly bottled and aged pale lager beers determined with the 12° and 90° dual angle laboratory hazemeters and 10° to 90° range photogoniometer were compared and evaluated. The instruments were standardised in EBC formazin units. In freshly bottled beer, the forward (12°–25°) haze values were smaller approximately by a factor of three than the nephelometric (90°) values which yielded 0.33 EBC units. In aged beer, the forward haze was greater than the nephelometric one. Whereas the aged beer showed the greatest and the fresh beer the lowest intensity of scattered light, the formazin suspension intensity was in between. Due to the standardisation of the beer scattered intensities by relation to that of formazin, the standardised nephelometric haze in non-aged beer was greater than the forward haze, and vice versa in aged beer. The greater forward than the nephelometric haze in aged beer was caused by the growth of haze particles above the mean size of formazin particles which was larger than 2 μm as confirmed by the particle size distribution measurement.


1976 ◽  
Vol 31 ◽  
pp. 73-73
Author(s):  
C.L. Ross

Observations to determine the radiance of forward scattered sunlight from particles in lunar libration regions have been attempted with the white light coronagraph on Skylab. The libration regions could not be distinguished against the solar K + F coronal background; the upper limit to the libration cloud radiance is determined to be 2.5 × 10−11 Bo, where Bo is the radiance of the mean solar disk. Employing models of the particle type and size distribution in the libration clouds, density enhancements have been calculated on the basis of the upper limit of the forward scattered radiance presented herein, and on the basis of earlier observations of the libration region backscattered radiance. The cases where the power law particle size distribution exponent K and complex index of refraction m are 2.5, 1.33-0.051 and 2.5, 1.50-0.051, respectively, are inconsistent with the forward and backscatter observations. Finally, the brightness contrast of remaining possible models of the libration clouds with respect to the K- and F-coronal background is calculated, and is shown to be a maximum in the vicinity of elongation angle ~30°.


2006 ◽  
Vol 11-12 ◽  
pp. 315-318 ◽  
Author(s):  
Seigo Nishimura ◽  
Y. Hayashi ◽  
Tsuneo Suzuki ◽  
Tadachika Nakayama ◽  
Hisayuki Suematsu ◽  
...  

A pulsed wire discharge (PWD) apparatus for mass production of nanosized powders was developed. The apparatus had a wire feeder, and could prepare 1.5 g of Cu powder in 200 sec. The mean surface diameter of Cu powder was 86 nm. The particle size distribution of the powder prepared by 100 discharges was increased than that by one discharge. In addition, the median diameter of the powder after the 100 discharges was larger than that by one discharge. A part of the nanosized powders in production chamber of the apparatus would be grown by the deposition of plasma or vapor formed by the next discharge.


1999 ◽  
Vol 28 ◽  
pp. 111-117 ◽  
Author(s):  
A. Khatwa ◽  
J. K. Hart ◽  
A. J. Payne

AbstractA technique proposed by Hooke and Iverson (1995) to identify deformed subglacial sediments is reviewed and tested, based on two main objectives. First, an investigation of whether the fractal dimension can distinguish between non-deformed and deformed facies; for which we compare supraglacial and subglacial facies explicitly. Second, an evaluation of whether the fractal dimension can be used as a diagnostic criteria to discriminate between different styles and degrees of basal deformation. This is tested using a range of sediments from the deformation continuum suggested by Hart and Boulton (1991b). Sixteen subglacial samples were selected from Quaternary sites in England and three supraglacial samples from the modern Haut Glacier d’Arolla, Switzerland. The mean fractal dimension for the subglacial diamicton matrix facies was 2.92, similar to findings of 2.90 by Hooke and Iverson (1995) for their basal tills. The supraglacial facies displayed a mean fractal dimension of 2.83, which is unusually high for facies which are assumed to be undeformed. A Mann—Whitney U test showed that fractal dimensions of supraglacial and subglacial diamicton matrix facies were not significantly different. No significant difference was found between the fractal dimensions of the different tectonic facies within the subglacial group. It may be impossible to separate the subglacial and supraglacial facies because of complex debris paths within the glacier. Grain fracture or parent lithology may affect the particle-size distribution of subglacial facies.


2006 ◽  
Vol 326-328 ◽  
pp. 445-448 ◽  
Author(s):  
Beom Goo Lee ◽  
Yeon Ho Jeong ◽  
Dong Ha Cho ◽  
Kang Yol Lee ◽  
Wie Soo Kang

It is investigated whether ginseng can be milled into super fine powder below 50μm, changing the circumferential velocity of impeller of a turbo mill(100, 110 and 120m/s). The mean particle size is 113.3μm in control but is decreased abruptly into 11.9μm at 120m/s. The largest particle diameter at 97% of volume distribution is reduced into below 32μm at 120m/s from below 725μm at control. The particle size distribution between d(0.1) and d(0.9) is 334μm at control, but is decreased into less than 26μm in all conditions after milling. It shows that ginseng can be milled into super fine powder by the turbo mill, which has the narrow particle size distribution.


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