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1

Hyperspectral indices developed from multi-angular bidirectional reflectance can trace the particle size of granite

Wu Mengjuan, Jin Jia, Wang Jinlin, Wang Quan

Acta Geophysica

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2023

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Vol. 71, no. 1

193--208

EN

The particle size of a rock is one of the critical physical properties related to a series of geological processes. While the prevalent photometric studies performed to quantitatively assess the physical properties of minerals and rocks rely much on radiative transfer model inversions from surface reflectance, the complicated procedures required seriously limit their applications. Instead, this study has attempted an empirical-based approach to trace the particle size of granite based on multi-angular bidirectional reflected information, providing a practical method for quickly assessing the physical properties of minerals and rocks from surface reflectance. Five common hyperspectral index types together with different spectral preprocessing treatments, including the original hyperspectral reflectance, derivative analysis, continuum-removed reflectance, and apparent absorption spectra, were screened to explore the best indices for both measured and Hapke model-simulated datasets. The results suggested that the normalized difference index (ND) calculated from the apparent absorption spectra using the wavelengths of 1 325 nm and 1 800 nm is a robust index for tracing the particle size for both measured and simulated datasets.

2

Wpływ właściwości kruszyw na procesy ich klasyfikacji

Ławińska Katarzyna, Modrzewski Remigiusz

Kruszywa : produkcja - transport - zastosowanie

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2020

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Nr 2

38--47

PL

Niniejsza praca analizuje wpływ właściwości materiałów sypkich i kruszyw mineralnych na proces przesiewania tych mediów ziarnistych. Właściwości te to przede wszystkim wilgotność materiału i związany z nią współczynnik tarcia wewnętrznego, jak również kształt i rozmiary ziaren. Ponadto wprowadzono pojęcie tzw. funkcji wypływu, która również może być ważnym narzędziem opisującym właściwości materiałów w ich procesach przeróbczych.

EN

This paper analyses the influence of the properties of bulk materials and mineral aggregates on the sieving process of these granular materials. These properties include first of all: the water content of a material and the relevant coefficient of internal friction as well as particle shape and size. Moreover, the notion of the so called outflow function is introduced, which can be an important tool describing the properties of materials during their processing.

3

Long-term effect of different particle size distributions of waste glass powder on the mechanical properties of concrete

Omer Brwa, Saeed Jalal

Architecture Civil Engineering Environment

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2020

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Vol. 13, no. 4

61--75

EN

In this paper, a comprehensive experimental investigation was conducted into the effect of the particle size distributions (PSDs) and percentages of waste powdered glass as a partial replacement of cement on the long-term mechanical behavior of concrete produced at two different cement levels. For this purpose, two different mixtures of concrete were used as reference mixtures; the first has a relatively low cement content (331 kg/m3), and the second has a relatively high cement content (490 kg/m3). Two different PSDs of glass powder (GP) labeled GP-A and GP-B ((55 μmGP-B) were used, and the considered GP content for the low cement content mixture (LCCM) and the high cement content mixture (HCCM) were (0%, 5%, and 10%) and (0%, 5%, 10%, and 15%) by weight of cement, respectively. The mechanical performance of all concrete mixtures at 180 days was investigated and evaluated in related tests as compressive strength and toughness, splitting and flexural tensile strength, elastic modulus, and compressive stress-strain behavior. The experimental results generally indicated that the compressive strength of GP-modified concrete improved significantly over the long-term age (180-days) compared to the early age (28-days). The contribution of PSDs of GP to enhancing the mechanical properties of concrete is insignificant compared to its replacement amount. Finally, independent of the PSDs, the incorporation of 10% GP for LCCM and 15% of GP for HCCM has a positive effect on the long-term mechanical properties of concrete, indicating that GP can be used as a replacement for cement.

4

Relationship between mineral magnetic properties and soil textural parameters

Kanu M. O., Meludu O. C., Basavaiah N., Oniku A. S.

Acta Geophysica

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2019

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Vol. 67, no. 2

517--532

EN

The study analyzed the relationship between mineral magnetic properties and particle size in order to determine the suitability of magnetic measurements to serve as particle size proxy for urban top soils samples collected from Jalingo, NE Nigeria. Pearson correlation analyses between mineral magnetic parameters (χlf, χfd%, χARM, SIRM, Soft IRM, ARM/SIRM) and particle size properties (PM2.5, PM10, clay, silt and sand) are reported. Results indicate that each particle size class shows different strength of correlation with magnetic parameters, implying that each particle class contains a proportion of magnetic minerals. For the whole data set (n = 154), χfd%, χARM and ARM/SIRM show significant positive correlation with the fine size fractions (PM2.5, PM10, clay and silt) but negatively correlated with the sand proportion, while χlf, SIRM and Soft IRM exhibit contrasting relationship. Of all the magnetic parameters, the magnetic parameters indicating fine-grained ferrimagnetic minerals (ARM/SIRM and χARM) have the strongest and most significant correlations. The nature of the magneto-particle size relationship is different when examined in terms of land use. The fact that magnetic properties and textural parameters have strong relationship indicates that magnetic methods could be considered a potential particle size proxy in Jalingo. However, since the relationship does not follow predictable and consistent patterns of other studies in top soils and sedimentary settings, it brings to fore the non-universality of the method. Hence, the type of relationship existing between magnetic and particle size properties in an environmental setting must be determined before applying the magnetic method as particle size proxy.

5

Effects Of Process Parameters On Cu Powder Synthesis Yield And Particle Size In A Wet-Chemical Process

Shin Y. M., Lee J. H.

Archives of Metallurgy and Materials

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2015

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Vol. 60, iss. 2B

1247--1250

EN

This study presents a simple wet-chemical process to prepare several micron-size Cu powders. Moreover, changes in powder synthesis yield and particle size are examined with different solvents, synthesis temperatures, and amounts of reducing agent during the synthesis. As a reducing agent and capping agent, L-ascorbic acid and polyvinyl pyrrolidone were used, respectively. The yields in distilled water or an ethylene glycol (EG)/distilled water mixture were higher than that in EG alone, and the yield increased with increasing temperature owing to a lower Δ Gred value. Increasing the L-ascorbic acid concentration also increased the yield. The Cu powder synthesized in 3 h at 90°C in distilled water with 272.8 mM of L-ascorbic acid showed the lowest average particle size of 2.52 μm, indicating mechanisms of short burst nucleation and reduced growth via the increased reduction rate of Cu ions. It is estimated that the nucleation step was nearly completed within 10 min in this system. The Cu powders synthesized in an ethylene glycol/distilled water mixture presented an average particle size of 3.76 μm and the highest yield of 87.9%.

6

Dissolved state of cellulose in ionic liquids - the impact of water

Kuzmina O., Sashina E., Troshenkowa S., Wawro D.

Fibres & Textiles in Eastern Europe

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2010

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Vol. 18, no. 3 (80)

32--37

EN

The aggregate size of cellulose dissolved in 1-ethyl-3-methylimidazolium acetate (EMIMAc) and 1-butyl-3-methylimidazoluim chloride (BMIMCl) was measured by static and dynamic light scattering. Examined were cellulose solutions containing various amounts of water. The impact of water on the size of cellulose particles in the solutions tested has been defined based upon the measurement results.

PL

W artykule przedstawiono wyniki badań rozmiarów agregatów celulozowych w roztworach octanu 1-etylo-3-metyloimidazolu (EMIMAc) i chlorku 1-butylo-3-metyloimidazolu (BMIMCl) otrzymanych podczas pomiarów statycznego i dynamicznego rozpraszania światła. Zbadano roztwory celulozy ze zróżnicowaną zawartością wody oraz określono wpływ wody na rozmiar cząstek celulozowych w badanych roztworach.

7

Badania kinetyki rozrostu i koagulacji fazy gamma' w superstopie niklu EI-867

Majka H., Sieniawski J.

Archiwum Nauki o Materiałach

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1998

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t. 19, nr 4

237-254

PL

Przedstawiono wpływ temperatury i czasu starzenia na kinetykę rozrostu i koagulacji gazy gamma' w przemysłowym stopie EI-867. Określono udział objętościowy oraz wyznaczono zakresy temperatury rozrostu i koagulacji fazy gamma'. Na podstawie pomiaru rozmiarów cząsteczek w próbkach wyżarzonych w określonej temperaturze w dostatecznie długim czasie wyznaczono stałą K szybkości rozrostu i określono energię aktywacji tego procesu. Opracowano histogramy rozkładu rozmiarów czasteczek i porównano z rozkładem teoretycznym. Otrzymane wyniki potwierdziły, że rozrost cząsteczek fazy gamma' w stopie EI-867 odbywa się poprzez kontrolowany dyfuzją transport materii cząsteczka-osnowa i jest zgodny z teorią LSW.

EN

In the paper influence of aging and temperature on the gamma'-phase growth and coagulation in commercial nickel-base EI-867 alloy has been presented. On the basis of particle size measurements in specimen after annealing in particular temperature for appropriate time, growth rate constant K, and growth activation energy have been obtained and compared with theoretical distribution. Results of the investigation proved that diffusion controlled particle-matrix mass transport is the mechanism of gamma'-phase particle growth in EI-867 alloy, which is in agreement with LSW theory.