Particle Size Distribution Research Papers (original) (raw)

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- Nonlinear dynamics, Materials modeling, Computer Program, Particle Size

This article reports the results of an investigation into the efficiency of mechanical activation to increase the reactivity in alkali activated mortar synthesized from low-grade clay. Mechanical activation significantly changed the structure of clay, increasing the specific surface area, and decreasing the particle size. The 7-day compressive strength of mortar synthesized from untreated clay was 31.7 MPa, which increased to 35.3 after 4 h milling. A further increase of grinding time to 8 h did not result in any increase in compressive strength which is attributed to a decrease in the workability. However, the extent of reactivity did significantly increase as determined from solid-state MAS NMR, FTIR, and EDS analyses. Solid-state MAS NMR results revealed the increased formation of Q 4 (2Al) silicon sites, which is correlated with improved reaction. Furthermore, the EDS and FTIR analysis results indicated greater incorporation of aluminium into the matrix structure with increased grinding time.

- by Morteza Tahmasebi Yamchelou
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- Materials Science, FTIR spectroscopy, Solid State NMR, CT scanning
- by Vasudeva Singh
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- Chemistry, Quality Improvement, Functional Food, Rice bran oil
- by Kenneth Gunter
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- Mechanical Engineering, Modeling, Evaporation, Fluids
- by Douglas Ruthven
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- Engineering, Magnetic Properties, Polyethylene, Composite Material
- by Adalberto Noyola
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- Chemistry, Medicine, Multidisciplinary, Ultrafiltration
- by Kent Rausch
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- Analytical Chemistry, Distillation columns, Molecular Sieve, Coefficient of Variation
- by Hartwig Steckel
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- Chemical Engineering, Light Scattering, Quality Control, Pharmaceutical industry
- by Grzegorz Łysiak
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- Mechanical Engineering, Chemical Engineering, Chemistry, Powder technology
- by Claudia Timmreck
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- Evaporation, Multidisciplinary, Stratosphere, Seasonality
- by Michel COURNIL and +1
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- Mechanical Engineering, Chemical Engineering, Kinetics, Chemical Engineering Science
- by Naomi Harley
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- Environmental Science, Quality Control, Exposure Assessment, New York City

Fly Ash (FA) from South African power stations was successfully used to treat Acid Mine Drainage (AMD) and the insoluble residual solids that were obtained as a result of the reaction between FA and AMD proved suitable as a backfill material for mine stabilization. Particle Size Distribution (PSD) of FA varies from time to time depending on the coal burning conditions in the power station. Such variability in PSD of FA could influence its capability to neutralize AMD as well as the flow behaviour of residual solids that have to be transported hydraulically to the backfill site. The objective of this paper is to study the influence of variability of PSD on the above mentioned properties. The FA from Arnot power station in South Africa was used for this study. PSD analysis showed that the FA particle size distribution was <25 m (38%), 25-75 m (42%) and 75-150 m (14%). The % of fine and coarse particles (in the context of this study) could influence the neutralization capacity of FA...

- by Paul Slatter
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- Acid Mine Drainage, South Africa, Fly Ash, South African
- by Candan Hamamci and +1
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- Particle Physics, Kinetics, Activation Energy, Nitrogen

In order to develop efficient photocatalytic TiO2 films and membranes for application in water and wastewater treatment and reuse systems, there is a great need to tailor-design the structural properties of TiO2 material and enhance its... more

- by Elias Stathatos
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- Engineering, Materials Science, Design, Adsorption
- by Hainer Wackerbarth
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- Chemical Engineering, Food, Interaction, Emerging Market
- by nicole scheifhacken
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- Water, Biomass, Environmental Monitoring, Phytoplankton
- by Yallapu Murali Mohan
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- Engineering, Nanoparticle, Morphology, Polymer
- by Norman Peinemann
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- Soil Science, Biological Sciences, Environmental Sciences, Water use efficiency
- by Jai Mittal
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- Materials Engineering, Electron Microscopy, Crystallite Size, X ray diffraction

... J. Germán Rodríguez and Adolfo Uriarte ... View larger version (15K), Table 1. Pearson product moment correlations between cumulative percentiles, measured by laser diffractometry and by dry sieving on sandy marine sediments (n = 68).... more

- by Adolfo Uriarte
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- Engineering, Earth Sciences, Coastal, Grain size
- by Robert N Grass
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- Engineering, Materials Chemistry, Magnetic Materials, Nanoparticles
- by Pooja Kumari
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- Materials Engineering, Catalysis, Nanoparticle, Morphology
- by isabel Lima
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- Engineering, Environmental Science, Technology, Production
- by J. Leys
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- Air Quality, Water resources, Multidisciplinary, Environmental Sciences
- by Carlos Londono
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- Mechanical Engineering, Chemical Engineering, High Pressure, Carbon

We consider the fragmentation process with mass loss and discuss self-similar properties of the arising structure both in time and space, focusing on dimensional analysis. This exhibits a spectrum of mass exponents theta, whose exact numerical values are given for which x(-theta) or t(theta z) has the dimension of particle size distribution function psi(x,t), where z is the kinetic exponent. We obtained conditions for which the scaling and fragmentation process altogether breaks down, and we give an explicit scaling solution for a special case. Finally, we identify a new class of fractals ranging from random to nonrandom and show that the fractal dimension increases with increasing order and a transition to a strictly self-similar pattern occurs when randomness completely ceases.

- by Kamrul Hassan
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- Engineering, Kinetics, Dimensional Analysis, Mathematical Sciences

Particle concentrations and size distributions have been measured from different heights inside and above a boreal forest during three BIOFOR campaigns (14 April–22 May 1998, 27 July–21 August 1998 and 20 March–24 April 1999) in Hyytiälä, Finland. Typically, the shape of the background distribution inside the forest exhibited 2 dominant modes: a fine or Aitken mode with a geometric number mean diameter of 44 nm and a mean concentration of 1160 cm−3 and an accumulation mode with mean diameter of 154 nm and a mean concentration of 830 cm−3. A coarse mode was also present, extending up to sizes of 20 μm having a number concentration of 1.2 cm−3, volume mean diameter of 2.0 μm and a geometric standard deviation of 1.9. Aerosol humidity was lower than 50% during the measurements. Particle production was observed on many days, typically occurring in the late morning. Under these periods of new particle production, a nucleation mode was observed to form at diameter of the order of 3 nm and, on most occasions, this mode was observed to grow into Aitken mode sizes over the course of a day. Total concentrations ranged from 410–45 000 cm−3, the highest concentrations occurring on particle production days. A clear gradient was observed between particle concentrations encountered below the forest canopy and those above, with significantly lower concentrations occurring within the canopy. Above the canopy, a slight gradient was observed between 18 m and 67 m, with at maximum 5% higher concentration observed at 67 m during the strongest concentration increases.

- by Edo Do
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- Environmental Engineering, Modeling, China, Public Health
- by Sheng-Bo Wang
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- Materials Engineering, Electron Microscopy, Powder Diffraction, Nanostructures
- by Milena Corredig
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- Heat Treatment, Animal Production, Soybean, Size Distribution
- by Masaru Okabe
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- Materials Engineering, Polymer Engineering, Polymerization, Phase Transitions
- by Edmond P Byrne and +1
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- Mechanical Engineering, Chemical Engineering, Packaging, Modeling

Nanosized zirconium oxide (ZrO2) powders were prepared by adding NaOH to a zirconyl chloride aqueous solution under microwave-hydrothermal conditions. The obtained results showed that the tetragonal polymorph increased with increasing NaOH concentration in the starting solution and reached the maximum value by using 1M ZrOCl2. The microwave-assisted hydrothermal synthesis is expected to be able to process continuously, and may lead to energy savings because of rapid heating to temperature and increased kinetics of crystallization. This method is very simple and can lead to powders with desirable characteristics such as very fine size, narrow size distribution, and good chemical homogeneity.

- by Federica Bondioli
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- Materials Engineering, Mechanical Engineering, The, Hydrothermal Synthesis
- by Mingwan Young
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- Mechanical Engineering, Chemical Engineering, Design, Modeling
- by Wolfram Heineken
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- Mechanical Engineering, Chemical Engineering, Nonlinear dynamics, Modeling

The size distribution of polycyclic aromatic hydrocarbons (PAH) was determined for airborne particles from a large city with high vehicular traffic. The analytical method was optimised and validated using NIST standard reference material (SRM 1649a Urban Dust). The 16 priority PAH listed in the US-EPA were Soxhlet-extracted from filtered particulate matter and then fractionated using on-column chromatography. The aromatic fraction was quantified by gas chromatography-mass spectrometry. Real samples of particles collected in Seville (Spain) were analysed using the validated method. Values for the total concentration of PAH in the air, as well as the concentrations of each PAH in six particle-size ranges were obtained. Values of the PAH in TSP, PM10, PM2.5 and PM1 were assessed.

- by Antonio José Fernández Espinosa
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- Engineering, Environmental Monitoring, Filtration, Spain
- by Sumrit Wacharasindhu
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- Engineering, Nanoparticle, Thermochromism, Photopolymerization
- by Sohrab Rohani
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- Chemical Engineering, Modeling, Mineral Processing, Ultrasound
- by Thava Vasanthan
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- Chemical Engineering, Food, Scanning Electron Microscopy, Composition

Because the particle number concentration in the area of the metal and alloys operation with the highest risk exceeded by at least two orders of magnitude the concentrations in other areas, particle number was considered as possibly a better metric (ref. B-2). Number concentration is strongly influenced by the smaller particle sizes. The mean particle size for the high risk

- by Michael McCawley
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- Sampling methods, Risk factors, Particle Size, Size Distribution
- by Michael Hannigan
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- Environmental Engineering, Air Quality, Atmospheric Science, Biomass
- by Dmitri Talapin
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- Engineering, Surface modification, Semiconductor, Surface

The particle size distribution of faecal pellets produced by the tubificid worm Tubifex tubifex in laboratory culture, was measured with a Coulter® Multisizer. The faecal material from worms cultured in a range of sediments was composed of particles with a mean diameter of less than 63 μm, and only a few isolated larger particles were found by microscopic analysis. This suggests that this species actively selects the silt-clay fraction, avoiding larger sand particles. A more detailed analysis of faeces revealed that about 75%, by volume, was composed of particles with a mean diameter < 25μm, and the mode was < 10μm. T. tubifex fed selectively on the organic rich particles of the sediment, and this feeding was independent of particle size. Measurement of the organic content of faeces (measured as % loss on ignition) showed that they had a consistently higher organic content than the sediment, considered as whole sediments or the <63 μm sieved fraction. On the basis of these results, we hypothesise that this species exhibits two levels of selectivity in its feeding behaviour. Thus selection is primarily based on particle size, avoiding the ingestion of sand particles and also, on the preferential selection of particles associated with organic material, within the fine (silt-clay) fraction of the sediment.

- by Jesus Angel Arrate Jorrin and +3
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- Earth Sciences, Biological Sciences, Environmental Sciences, Particle Size
- by Joselio Vieira
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- Chemical Engineering, Microbiology, Food, Scanning Electron Microscopy
- by Sudhagar Mani
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- Model development, Mathematical Model, Particle Size, Size Distribution
- by Robert Rusinek
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- Food Engineering, Potato, Oscillations, Shear Stress