Temat: particle size distribution

Skocz do pozycji: 1.

Tytuł:: Ultrasonic Properties of Magnetic Nanoparticles with an Additional Biocompatible Dextrane Layer
Autorzy:: Dąbek, L.
Hornowski, T.
Józefczak, A.
Skumiel, A.
Tematy:: magnetic nanoparticles
ultrasound
particle size distribution; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/176605.pdf Link otwiera się w nowym oknie
Opis:: The temperature dependence of the particle size distribution (PSD) of the magnetic fluid with an additional biocompatible dextran layer was studied using a ultrasonic method. The measurements of the ultrasound velocity and attenuation were carried out as a function of the volume concentration of magnetite particles at temperatures ranging from 15°C to 40°C. In order to extract the PSD from ultrasonic measurements, the theoretical model of Vinogradov-Isakovich was used. The extraction of PSD from the ultrasonic data requires also the measurements the density and viscosity of the ferrofluid samples. The calculated PSD of the magnetic fluid with an additional biocompatible layer shows a greater thermal stability than that of a magnetic fluid with a single surfactant layer.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Effects of operating pressure and stand-off distance on coal comminution by waterjet
Autorzy:: Li, Y.
Galecki, G.
Şen, G. A.
Şen, S.
Tematy:: coal
waterjet
comminution
particle size distribution; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/110840.pdf Link otwiera się w nowym oknie
Opis:: Comminution of coal to ultrafine sizes by high-pressure waterjet coupled with cavitation cell provides a novel method for preparation of coal-water fuels for next generation, near-zero emission electric power generation. To establish the fundamental performance of the waterjet mill, the effects of the operating pressure and stand-off distance were comprehensively investigated using a high ash bituminous coal. The comminution products were evaluated in terms of the particle size, particle size distribution, and surface area change. The experimental results indicated that the waterjet-mediated comminution of coal was strongly affected by all these operating parameters. Higher operating pressure led to finer products, while the efficiency of the waterjet mill in terms of particle size strongly depended on the stand-off distance. This research provides a deeper insight into the high-pressure waterjet for coal comminution and a basis for process parameter optimization.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Influence of the sand particle shape on particle size distribution measured by laser diffraction method
Autorzy:: Polakowski, C.
Sochan, A.
Bieganowski, A.
Ryzak, M.
Foldenyi, R.
Toth, J.
Tematy:: sand
particle shape
particle size distribution
laser diffraction; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Agrofizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/25877.pdf Link otwiera się w nowym oknie
Opis:: The aim of this paper was to show how the shape of sand particles affects the results of particle size distribution obtained by the laser diffraction method. On the basis of the results obtained one can conclude: the shape of the investigated particles influences particle size distribution obtained by the laser diffraction method. This phenomenon occurs in the sand fraction, as shown in our investigation. The importance of this effect depends on the type of the measured material and on the aim of the investigations. For most researchers in soil science and sedimentology who investigate sand fractions, this impact can be negligible. Further investigations with other soil and sediment fractions are needed.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Studies on the Tailoring of Particle Size and Micromeritic Properties of Reduced Shock Sensitivity RDX (RSS-RDX)
Autorzy:: Ramavat, V.
Sarangapani, R.
Reddy, S. T.
Patil, R. S.
Gore, G. M.
Sikder, A. K.
Tematy:: crystallization
RSS-RDX
micromeritics
particle size distribution; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:: https://bibliotekanauki.pl/articles/951500.pdf Link otwiera się w nowym oknie
Opis:: The microstructure of explosive particles, as well as formulations, has a significant influence on the shock sensitivity of various energetic formulations. Particle shape and specific size distributions are always important considerations in explosives processing in order to realize better process parameters. The present study aimed to explore crystallization variables required to achieve a specific particle size of Reduced Shock Sensitivity RDX (RSS-RDX). Crystallization process factors such as cooling rate, agitator speed and configuration, etc. have been systematically studied to understand their effect on the particle size. The study also established the crystallization process parameters required to tightly control a specific particle size distribution ranging from 50 to 500 μm by cooling crystallization. Fine particles ranging from 15 to 30 μm were prepared by an ultrasonication technique. Ultrasonic process parameters, including temperature, time and ultrasonic frequency, were studied and the process conditions were optimized. Micromeritic characterization of RSS-RDX revealed the nature of flowability, which in-turn is useful in identifying the ease of processability. Overall, our interest stemmed from an investigation which showed that careful optimization of crystallization variables can lead to a specific particle size distribution.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Mathematical models of particle size distribution in simulation analysis of high-pressure grinding roll operations
Autorzy:: Saramak, D.
Tematy:: HPGR
comminution
particle size distribution
ore processing; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/110253.pdf Link otwiera się w nowym oknie
Opis:: The high-pressure grinding roll (HPGR) technology is currently one of the most efficient methods of hard ore comminution from the scope of the energy consumption. Throughput and energetic models of performance are quite well developed, but technological models predicting the comminution effects still needs an in-depth research. In the paper author presents the method of modeling of HPGR products’ particle size distribution by using suitable mathematical models. A basis of the HPGR perfor-mance assessment and HPGR-based crushing circuits design is a product’s particle size distribution. In order to precisely determine the particle size distribution of a HPGR product, parameters of product’s particle size distributions should be conditional on the main technical parameters of the roller press like operating pressure and the speed of rolls. The most accurate approximation of a distribution of size parti-cle appears to be Weibull’s truncated distribution and it is possible to obtain significant relationships between the approximation formula and the value of operating pressure, or feed characteristics. It makes possible a determination of mass recoveries of the product’s respective size fractions and the productivity planning. Instead of pressure, the other HPGR operating parameters can be applied, but the pressure value appears to produce the most relevant relationship. A determination of HPGR product’s particle size dis-tribution is a basis of the press operation simulation analysis.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: A study of selected properties of rhenium sulphide dispersion
Autorzy:: Pawlak, D. W.
Parus, J. L.
Skwarek, E.
Janusz, W.
Tematy:: rhenium sulphide
particle size distribution
zeta potential; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/951830.pdf Link otwiera się w nowym oknie
Opis:: Due to potential application of rhenium sulphide in medicine and industry, this study is focused on the properties of synthetic and commercial rhenium sulphide. The main reaction of rhenium sulphide preparation involves potassium perrhenate and sodium thiosulphate in the acidic environment giving a mixture of rhenium sulphide and sulphur. The next step is removing sulphur by its dissolution in ether. Stabilization by Povidone K-25 is needed to obtain rhenium sulphide dispersed with the grain size of 0.5–4 m. The extrapolated value of pHiep for synthesised rhenium sulphide is 2.3 whereas for commercial samples this value is lower than 2. For synthetic sample a dependence of zeta potential on the carrier electrolyte concentration is found. It is larger than that for the commercial sample, probably due to surface oxidation during synthesis or purification.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Evolution of droplet size distribution in selected nebulizers
Autorzy:: Dobrowolska, Katarzyna
Sosnowski, Tomasz R.
Tematy:: spraying
liquid atomization
aerosol dynamics
particle size distribution; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/1450682.pdf Link otwiera się w nowym oknie
Opis:: Nebulizers are the class of atomizing devices used to disperse liquids to fine droplets. They found their application in selected technological (typically: small-scale) processes, but their most common use is related to the generation of medicinal aerosols for inhalation. In this work we present the experimental data on the evolution of the size distributions of water droplets generated by two nebulizers (pneumatic and vibrating-mesh) as a result of aerosol mixing with the ambient air. Such a process reflects the real situation, where aerosol emitted from a nebulizer is diluted by additional air sucked by a patient during inhalation. Droplet size distribution was determined by laser diffraction, and these results were further discussed including the data of the aerosol velocity measured by the Laser Doppler Anemometry (LDA). It was demonstrated – as expected - that dilution with the ambient air with moderate humidity results in the intense evaporation of the smallest droplets. However, larger droplet may be saved to a different degree depending on the velocity and geometry of the aerosol cloud emitted from the nebulizer, and on the volume of the diluting air. These parameters have an influence on the droplet coalescence which is another process shaping the droplet size distribution in the studied conditions. The results can deepen the understanding of the mist dynamics which can be applied in various fields of colloidal science and technology.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: The use of particle size distribution of soils in estimating quality of mountain forest sit
Autorzy:: Wanic, Tomasz
Zwydak, Maciej
Błońska, Ewa
Lasota, Jarosław
Wydawca:: Instytut Badawczy Leśnictwa
Opis:: Przemysław Szmit
The physical and chemical properties of soil are the basic features that are used in the assessment of mountain sites. The aim of this study was to produce a simple key for classifying forest sites in mountain areas using soil particle size distribution. 200 plots (standard typological space) were selected for examination, most of which are typical of the Carpathians – being dominated by flysch rock. A few plots were located in the Sudety and Tatra Mountains, which have a different surface geology, mostly metamorphic rock and granite. The study proved that soil properties (reaction, base saturation, content of base cations, organic carbon and nitrogen) are helpful in distinguishing and assigning soils to particular site types. The particle size distribution of forest mountain sites separated into different categories in terms of productivity. These results can be used to improve the classification of forest mountain sites
Dostawca treści:: Repozytorium Centrum Otwartej Nauki

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Skocz do pozycji: 9.

Tytuł:: Effect of two-stage thermal disintegration on particle size distribution in sewage sludge
Autorzy:: Kaczmarek, A. M.
Gaca, J.
Tematy:: laser diffraction
particle size distribution
sludge
thermal hydrolysis; Pokaż więcej
Wydawca:: Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Powiązania:: https://bibliotekanauki.pl/articles/777862.pdf Link otwiera się w nowym oknie
Opis:: The effect of two-stage thermal disintegration of sewage sludge on the particle size distribution using laser diffraction method has been studied. The sludge was sampled from municipal sewage treatment plant after each stage of disintegration. The first stage of disintegration known as homogenization proceeds at temperature of 70-90°C and pressure of 3 bar, the second stage called thermal hydrolysis was performed at temperature of 160-170°C and pressure of 6 bar. It was found that the first stage of disintegration has the strongest impact on the reduction of the sludge particle size and changes in chemical properties. The maximum size of the particles from raw sewage before disintegration was 310 μm. After first stage of the process average size of the particles was 250 μm, and during the second stage it was reduced to 226 μm. Sludge disintegration degree (DDCOD) of 59% confirms high effectiveness of the process. We established that the redox potential (Eh) of sludge effluents was changed after each step of the studied process. Furthermore, chemical oxygen demand (COD) increases which leads to the conclusion that resizing of floccules is accompanied by hydrolysis.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Structure of aluminosilicate-supported nickel and iron oxides nanocomposites in gaseous and aqueous media
Autorzy:: Goncharuk, Olena
Dyachenko, Alla
Skwarek, Ewa
Ischenko, Olena
Andriyko, Lyudmila
Borysenko, Mykola
Sulym, Iryna
Sternik, Dariusz
Kowalska, Klaudia
Marynin, Andrii
Tematy:: oxide nanocomposites
NiO/FexOy
textural properties
particle size distribution; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/2146949.pdf Link otwiera się w nowym oknie
Opis:: A series of mixed oxides was synthesized by deposition of a guest phase on a highly dispersed oxide matrix. Fumed nanooxides SiO2, Al2O3, SiO2/Al2O3, and SiO2/Al2O3/TiO2 with the specific surface area of 65-91 m2/g were selected as highly dispersed matrices. NiO/FexOy was deposited as a guest oxide using solvate-stimulated modification of a surface of fumed nanocarriers with nickel nitrate and iron(III) formate and subsequent heat treatment up to 600 °C to form NiO/FexOy. The aim of this work was to study the influence of the composition and structure of fumed oxide matrices and deposited guest phase on the behavior of the composites in gaseous and aqueous media using XRD, nitrogen adsorption and SEM/EDX, and quasi-elastic light scattering (QELS) methods. The lowtemperature nitrogen adsorption isotherms have a sigmoid shape with a narrow hysteresis loop characteristic of mesoporous materials. The specific surface area of composites varies from 65 to 120 m2/g. SEM data show denser aggregate structure of nanocomposites compared to the initial carriers. The primary particle size was in the 30-60 nm range. According to QELS data, there is a tendency to form aggregates of 100 nm - 10 µm in size in the aqueous media. The XRD method shows that the deposited metal oxides are in the form of crystalline phases of NiO with crystallites of 7-23 nm in size, but the iron oxide reflexes were not identified for NiO-containing composites.
Dostawca treści:: Biblioteka Nauki

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