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1

Thermal treatment effect on the particle size distribution of alkaline earth metals hydroxyapatite

Diichuk Volodymyr, Diichuk Iryna

Scientiae Radices

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2023

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Vol. 2, Iss. 4

309--318

EN

Hydroxyapatites of certain alkaline earth metals were synthesised, and their phase composition was determined using X-ray phase analysis. Thermal modification of the studied compounds was performed at temperatures not exceeding 800°C. The laser diffraction method determined the size distribution of the samples subjected to thermal treatment. It was found that the mean particle size ranged from 5,48±1,28 to 126,71±3,68 μm. It has been demonstrated that particle aggregation and fragmentation processes are possible depending on the synthesised compounds' qualitative and quantitative phase composition and the modification temperature.

2

The effect of energies on the impact breakage characteristic of magnetite ores

Si Liang, Cao Yijun, Li Guosheng

Physicochemical Problems of Mineral Processing

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2023

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Vol. 59, iss. 1

art. no. 159098

EN

The energy applied during breakage is the key to enhancing the magnetite liberation degree and improving quality. The relationship between energy and liberation properties remains unclear due to various complicated factors affecting mineral liberation. Therefore, this work aims to study the effect of energy on the breakage characteristics of magnetite ores; the impact breakage test was conducted on magnetite particle groups at different energies using a drop weight impact tester; the statistical analysis was performed based on the fractal theory to research the particle size distribution; the fracture morphology and liberation properties of these ores were analyzed using scanning electron microscope and mineral liberation analyzer. Results show that the particle size distribution of magnetite after breakage conforms to the fractal law. The larger the energy, the greater the fractal dimension for this distribution, showing a linear relation between them, which implies that the fractal dimension can evaluate the breakage degree. The fracture morphology of magnetite ores indicates that as the energy increases, the intergranular fracture evolves into transgranular fracture, proving the influence of energy on fracture modes. It is found that the magnetite liberation degree first increases and then decreases with the rising of energy, indicating that the magnetite liberation can be improved at an appropriate amount of energy. The above conclusions provide a theoretical reference for optimizing energy and improving broken product quality.

3

The use of a laser diffractometer to analyse the particle size distribution of selected organic soils

Straż Grzegorz

Archives of Civil Engineering

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2023

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Vol. 69, nr 3

521--539

EN

This paper deals with the problem of determining the particle size distribution of selected organic soils from the vicinity of Rzeszów (Poland), using a laser diffractometer method, the knowledge of which will allow to determine the degree of differentiation or similarity of the tested organic soils in this aspect. The HELOS Laser Diffractometer manufactured by Sympatec GmbH was used for the tests. For proper analysis, the researches results in the form of graphs were grouped according to the content of organic substances in accordance with the standard classification. The conducted research was primarily aimed at presenting the grain differentiation and particle size distribution in terms of the applied method and comparing the test results of samples of selected, different organic soils, prepared using the same dispersion procedure and carried out in exactly the same test conditions, generated using capabilities of a diffractometer. Summing up, the laser diffractometer method presented in the article, although not fully verified in the case of organic soils, seems to be a the perspective method with capabilities allowing it to be nominated as an exceptionally useful method for the investigations of soft soils, including organic soils.

PL

W niniejszej pracy zaprezentowano wyniki analizy granulometrycznej 12 próbek wybranych gruntów organicznych pochodzących z okolic Rzeszowa. Grunty te, ze względu na ich cechy charakterystyczne, zaliczane są do gruntów słabonośnych, charakteryzujących się w stosunku do gruntów mineralnych, głównie niewielką wytrzymałością oraz małą sztywnością. Pomimo tych niekorzystnych właściwości obecnie grunty te znajdują się w obszarze zainteresowań inżynierii geotechnicznej z powodu coraz częstszego ich lokalizowania na terenach będących obiektem zainteresowania inwestorów. Posadowienie obiektów budowlanych czy konstrukcji inżynierskich na terenach, gdzie zalegają grunty słabonośne, w tym organiczne, jest wyjątkowo skomplikowane, pracochłonne i kosztowne a kluczem do bezpiecznego posadowienia jest prawidłowe określenie ich właściwości i parametrów geotechnicznych, a określenie składu ziarnowego jest jednym z podstawowych badań geotechnicznych. Niestety, na chwilę obecną nie opracowano dedykowanej metody, która byłaby w pełni wiarygodna w przypadku badań granulometrycznych gruntów organicznych. Opracowania naukowe w tym zakresie, najczęściej obejmują badania mineralnej części szkieletu gruntowego, które w warunkach laboratoryjnych zostały pozbawione materii organicznej, a to przede wszystkim ona decyduje o właściwościach gruntu organicznego. Skutkiem takiego modyfikowania próbek do badań jest fakt, że próbki te różnią się od naturalnego materiału pozyskanego ze złoża i oczywistym jest, że charakteryzują się zupełnie różnymi właściwościami. Wyników tych obydwu badań nie można bezpośrednio porównywać, mimo, że materiałem bazowym do badań granulometrycznych był ten sam grunt organiczny. Dlatego planując badania zaprezentowane w niniejszym opracowaniu, przyjęto że zostaną one przeprowadzone na próbkach gruntów organicznych o kompletnym szkielecie gruntowym, bez rozdzielania materiału badawczego na cześć mineralną i organiczną.

4

Permeability of sandy soils estimated from particle size distribution and field measurements

Gorczewska-Langner Wioletta, Gumuła-Kawęcka Anna, Jaworska-Szulc Beata, Angulo-Jaramillo Rafael, Szymkiewicz Adam

Archives of Civil Engineering

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2023

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Vol. 69, nr 4

187--204

EN

Accurate estimation of soil permeability is crucial in many geotechnical applications. Empirical and theoretical equations based on soil particle size distribution (PSD) offer a fast and cheap way for preliminary estimation of permeability in granular soils, however the results obtained from various formulas available in the literature often show significant discrepancies. While several comparative studies on this topic have been published, no definite conclusions can be drawn on the performance of the predictive equations in comparison with in-situ permeability measurements. Many formulas require porosity or void ratio as input parameter, which is difficult to obtain for granular soil in-situ. In this study we applied 30 predictive equations to estimate permeability of sandy soil in an outwash plain deposit. The equations were divided into 5 groups, based on their structure and the required input parameters. Empirical formulas were used to estimate the expected in-situ porosity range. The obtained permeability values were compared to the results of in-situ permeameter measurements and pumping tests. Significant differences in the results and in their sensitivity to porosity were found between the 5 groups of methods. In general, simple equations which do not include porosity were in better agreement with measurements than the other groups.

PL

Dokładne oszacowanie przepuszczalności gruntu (k) ma kluczowe znaczenie w wielu zastosowaniach geotechnicznych. Empiryczne i teoretyczne równania oparte na rozkładzie uziarnienia (PSD) umożliwiają szybką i tanią wstępną ocenę przepuszczalności gruntów ziarnistych, jednak wyniki otrzymane z różnych wzorów dostępnych w literaturze często wykazują znaczne rozbieżności. Chociaż opublikowano kilka badań porównawczych na ten temat, nie można wyciągnąć jednoznacznych wniosków dotyczących zgodności równań predykcyjnych z pomiarami przepuszczalności wykonanymi bezpośrednio w terenie. Wiele wzorów wymaga uwzględnienia współczynnika porowatości jako parametru wejściowego, co jest trudne do uzyskania w przypadku gruntu ziarnistego in-situ. W niniejszej pracy zastosowano 30 równań predykcyjnych do oszacowania przepuszczalności gleby piaszczystej na terenie równiny sandrowej, zlokalizowanej w pobliżu miejscowości Cekcyn w Borach Tucholskich, w północnej Polsce. Badania realizowane były w ramach projektu badawczego dotyczącego określenia zasilania wód podziemnych. Równania predykcyjne podzielono na 5 grup ze względu na ich strukturę oraz wymagane parametry wejściowe. Wzory empiryczne wykorzystano do oszacowania oczekiwanego zakresu porowatości in-situ. Otrzymane wartości przepuszczalności porównano z wynikami pomiarów in-situ wykonanych za pomocą permeametru Aardvark oraz uzyskanych w wyniku próbnego pompowania. Stwierdzono istotne różnice w wynikach uzyskanych poszczególnymi wzorami oraz ich wrażliwość na współczynnik porowatości. Najlepszą zgodność wyników empirycznych z pomiarami in-situ uzyskano dla tych grup formuł, które nie uwzględniają porowatości lub uwzględniają jedynie stopień zagęszczenia, gdyż metody te opracowano pierwotnie na podstawie wyników badań terenowych. Jak wykazano w pracy, większość metod opartych na pomiarach laboratoryjnych przewiduje k niższe niż pomiary in-situ, czego powodem między innymi może być anizotropia i niejednorodność gruntu, który zwiększa przepuszczalność poziomą in situ, ze względu na obecność poziomych warstw lub soczewek o małej skali. Cechy te są trudne do uchwycenia za pomocą wzorów opartych na krzywych PSD.

5

Structure of aluminosilicate-supported nickel and iron oxides nanocomposites in gaseous and aqueous media

Goncharuk Olena, Dyachenko Alla, Skwarek Ewa, Ischenko Olena, Andriyko Lyudmila, Borysenko Mykola, Sulym Iryna, Sternik Dariusz, Kowalska Klaudia, Marynin Andrii

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 2

art. no. 144375

EN

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.

6

Validation of measurements of pine pollen grain concentrations in Baltic Sea waters

Pawlik Magdalena M., Ficek Dariusz

Oceanologia

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2022

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No. 64 (2)

233--243

EN

Each spring, pine pollen coats considerable expanses of Baltic Sea surface waters. Measurements have shown that there are areas where its concentrations in this surface layer are so high that they are the dominant constituent of the suspended particulate matter (SPM) (Pawlik and Ficek, 2016). It then determines to a large extent the optical properties of the water surface, inter alia by modifying the sea colour. To date, however, the concentration of this constituent in the marine environment has rarely been studied, and its presence is not accounted for in the satellite algorithms used to define the composition and properties of sea water. This may well be the source of substantial errors in the remote sensing of the optical properties of the water and the measurement of concentrations of the optically important constituents it contains (chlorophyll a, TSM, CDOM). Measuring the concentration of pollen suspensions in Baltic Sea water, which often contains prodigious amounts of other SPM, is a daunting experimental challenge. Firstly, we characterized the pollen from pine trees growing near the southern shores of the Baltic Sea (northern Poland) using a microscope and two instruments routinely used in oceanography for measuring SPM size distributions: the LISST-100X and the Coulter counter. The measurements and analyses showed that a correct interpretation of the LISST-100X and Coulter measurements, is sufficient to count the number of pollen grains in distilled water alone. Furthermore, our laboratory analysis of the particle size distribution spectra enabled the fraction due only to pine pollen grains to be separated from the overall SPM. We then tested our method of analysing the SPM composition, which showed that the LISST-100x instrument is both a useful and an effective means for the in situ detection of the pine pollen that one sees in spring in Baltic waters.

7

Effects of different conditions on particle dynamics and properties in West-Estonian coastal areas

Uusõue Mirjam, Ligi Martin, Kutser Tiit, Bourrin François, Uudeberg Kristi, Kangro Kersti, Paavel Birgot

Oceanologia

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2022

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No. 64 (4)

694--716

EN

Satellite sensors are used to monitor water on a large scale. One of the key variables defining the water-leaving signal is suspended particulate matter (SPM) and thus it is important to understand its properties to improve remote sensing algorithms. However, only a few studies investigating the variability of SPM properties (concentration, nature and size) under different seasonal, weather and geographical conditions have been carried out in the Baltic Sea. We focused on relatively shallow areas (maximum depth of 10 m) where there is strong sediment transport by rivers and resuspension of the particles by wave action and advection by currents. Eleven field campaigns were conducted using a set of instruments measuring inherent optical properties, auxiliary data, and, in Pärnu Bay, also particle size distributions. The results showed that the SPM concentrations, particulate absorption, mass-specific particulate scattering, and backscattering varied temporally and spatially from 5.5–19.6 g m−3, 0–5.62 m−1, 0.08–1.45 m2 g−1, and 0.0009–0.25 m2 g−1, respectively. The spectral backscattering ratio, which in general is considered to be constant in bio-optical remote sensing algorithms, was actually wavelength-dependent and varied between 0.005 and 0.09 depending on the origin of the particles (organic or mineral matter), particle size distribution, weather conditions, and location. In situ particle size measurements in coastal waters of Pärnu Bay also showed that resuspended fine clay particles agglomerated into flocs of >30 µm in the brackish waters of the Baltic Sea having random shapes and different sizes.

8

Agroecological assessment of agricultural soils fertility in the Iglinsky region, the Russian Federation

Kiseleva Anna, Asylbaev Ilgiz, Mirsayapov Ramil, Kurmasheva Nadezhda

Journal of Water and Land Development

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2022

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no. 55

200--205

EN

The article provides an assessment of soil fertility indicators of agricultural lands in the northern forest-steppe of the Republic of Bashkortostan within the Iglinsky region (Russian Federation). The content of humus, mobile phosphorus, exchangeable potassium, the thickness of the humus horizon, granulometric composition, morphological properties and soil washout were studied. It was revealed that the soil-forming process occurs on rocks of different ages and genesis, such as diluvial carbonate and carbonate-free clays and heavy loams, limestone eluvium, sandstone eluvium and alluvial deposits, which determine the diversity of the soil cover. In the study area, water erosion processes are developing, influenced by anthropogenic and natural factors such as planar and linear washout on slopes with a steepness of more than 2-3° and high ploughing of agricultural land. In terms of humus content, low-humus and medium-humus soils are widespread, accounting for 45.5 and 40%, respectively. The soil map was corrected and digitised to identify the main types and subtypes of soils, indicating the varieties at a scale of 1: 25,000. Digitised maps, taking into account the current state of soil fertility, are used to develop projects for inter-farm and intra-farm land management of organisations of the agro-industrial complex, state cadastral valuation of agricultural land, determination of land tax and development of measures to improve soil fertility.

9

Extraction and Characterization of Silicon Dioxide from Volcanic Ash of Mount Sinabung, Indonesia: A Preliminary Study

Hasanah Moraida, Sembiring Timbangen, Sitorus Zuriah, Humaidi Syahrul, Zebua Fynnisa, Rahmadsyah

Journal of Ecological Engineering

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2022

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Vol. 23, nr 3

130--136

EN

The study was conducted on the extraction of volcanic ash from Mount Sinabung through the co-precipitation method to recover silicon dioxide (SiO2). The X-ray fluorescence (XRF) analysis showed that the SiO2 content in volcanic ash was 48.5%, and after extraction, it was 99.1%. The morphology shown by scanning electron microscope (SEM) indicated that SiO2 looks cleaner and tends to be the same size compared to the volcanic ash sample. The average particle size of volcanic ash and extracted SiO2 were 32.28571 ± 2.51259 and 12.97521 ± 0.60657 μm, respectively. The X-ray diffractometer (XRD) analysis showed that the crystal structure of the volcanic ash sample was quartz, maghemite, and cristobalite. Besides, the extracted SiO2 had an amorphous quartz crystal structure. The test conducted using Fourier transform infrared (FTIR) resulted in the absorption of 1095.57 cm-1 and 798.53 cm-1 for the Si‒O‒Si and Si‒OH groups which were the groups of siloxanes and silanols, respectively.

10

Influence of freeze–thaw cycling on properties of cementitious systems doped with fly ash having optimized particle size distribution

Demir Ilhami, Filazi Ahmet, Sevim Ozer, Simsek Osman

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 4

art. no. e189, 2022

EN

In this study, the particle size distribution (PSD) of class F and C fly ash (FA) was optimized using theory of the Fuller-Thompson. After defining the optimal size distribution, the distribution modulus (q) of 0.4 yields the best mechanical property results. The freeze–thaw up to 300 cycles on mechanical and permeability properties of 90-day cementitious composites incorporating optimized class F and C fly ash (5, 10, 15, 20, 25, and 30% by weight of cement) were investigated. Optimized FA has improved the mechanical and permeability properties of cementitious composites under freeze–thaw cycling by ensuring a better filler effect. The cementitious composite mortars with 20% optimized class C fly ash and class F fly ash replacement yielded high compactness and better mechanical properties than the control cementitious composite mortars without any fly ash replacement after 90 days. Finding the best particle size distribution of FA providing high compactness will save cement, reduce the carbon dioxide (CO2) emission that pollutes the environment in cement production, and contribute to the economy and environment.

11

Effects of hydrocarbon contamination on the engineering geological properties of Neogene clays and Pleistocene glacial tills from Central Poland

Dobak Paweł, Izdebska-Mucha Dorota, Stajszczak Piotr, Wójcik Emilia, Kiełbasiński Kamil, Gawriuczenkow Ireneusz, Szczepański Tomasz, Zawrzykraj Piotr, Bąkowska Anna

Acta Geologica Polonica

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2022

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Vol. 72, no. 4

529--555

EN

Petroleum products influence the engineering behaviour of the soil. Neogene clays and glacial tills from Central Poland were tested under laboratory conditions to evaluate the changes of selected physical and mechanical parameters: particle size distribution, particle density, swelling, shear strength and permeability. Four petroleum products were used in the experiments: diesel fuel, kerosene, jet fuel and mineral engine oil. The study revealed that even for the lowest degree of contamination the values of physical and mechanical properties of the soils changed significantly. Greater variation can be expected in soils contaminated with high-viscosity compounds. Also, higher relative changes were found for glacial tills than for Neogene clays. Consolidation tests revealed changes in soil permeability depending on the soil composition and the physical properties of the contaminant – considerable reduction of permeability was observed for glacial tills contaminated with light Jet fuel, while the reduction was lower for Neogene clays. The obtained results indicate the role of mesopores and the dimensionless pore pressure coefficient in changes of soil permeability. The methodological issues regarding testing and analysing the hydrocarbon-contaminated soils were also presented and discussed, which might be useful for researchers studying contaminated soils.

12

Zastosowanie dyfrakcji laserowej do badania stabilności emulsji typu olej w wodzie w przemyśle mleczarskim

Bomba Adriana, Babuchowski Andrzej, Adamczak Marek

Przemysł Spożywczy

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2021

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T. 75, nr 10

25--28

PL

Stabilność fizyczna emulsji w przypadku produktów żywnościowych to parametr ściśle związany z akceptacją konsumencką, który jednocześnie jest jednym z najważniejszych wyróżników jakości przy określaniu terminu przydatności do spożycia. Termodynamiczna stabilność żywności determinuje warunki przechowywania i możliwość transportu wyprodukowanych dóbr. W związku z powyższym ocena stabilności fizycznej emulsji jest ważnym elementem badań przemysłowych. Zagadnienie to ma szczególne znaczenie w przypadku przemysłu mleczarskiego, którego głównym surowcem jest mleko, czyli klasyczny przykład emulsji typu olej w wodzie (o/w). Dotychczasowe metody badania stabilności emulsji typu o/w opierały się na analizie wielkości kuleczek tłuszczowych z wykorzystaniem mikroskopu optycznego. Postęp naukowy i techniczny doprowadził do dezaktualizacji normy PN-A-86059:1975, która utraciła statu „uznanej reguły technicznej” i została wycofana bez zastąpienia. Stabilność emulsji typu o/w, określana na podstawie rozkładu wielkości kuleczek tłuszczowych jest coraz częściej badana z wykorzystaniem dyfrakcji laserowej.

EN

The physical stability of emulsions in case of food products is a parameter closely related to consumers’ acceptance, as well as one of the most important determinants of the products’ shelf life. Thermodynamic stability determines the conditions of storage and transportation of manufactured goods. Therefore, the research on emulsion physical stability is an important part of industrial research. This topic is of particular importance for dairy industry, where the raw material is milk – a classic example of oil-in-water (o/ w) emulsion. The analytical methods used so far to determination the stability of o/w emulsions’ stability have been based on the analysis of the size of fat globules using an optical microscope: PN-A-86059: 1975. However, scientific and technical progress has led to the obsolescence of the quoted standard, which lost the status as the “recognized technical rule” and was withdrawn without replacement. Currently, the stability of o/w emulsions, determined by the fat globules’ size distribution is being studied by means of laser diffraction.

13

Analysis of Proportional Scopes on Probability Density Functions of Random Chords of Spherical Particles

Gurgul D.

Archives of Foundry Engineering

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2021

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Vol. 21, iss. 4

61--66

EN

The paper presents an experimental confirmation of the fact that if a three-dimensional volume does not contain spherical particles with particular size, the Probability Density Function (PDF1) of half-chord lengths has proportional ranges. This fact has been deduced in work [1] during the derivation process of the Probability Density Function (PDF3) that maps the particle radii on the basis of data (PDF1) collected from flat cross-sections. The experiment has been executed virtually by using a simple computer program written in the C++11 language. The computer generation of particles allowed imposing various kinds of known PDF3 and the ranges in which the particles could not be created. Next, the virtual nodules have been used to produce sets of chords that served as input data to create histograms that approximated the continuous PDF1. Having such histograms, it was possible to reveal proportional scopes of the PDF1. The proportional dependencies occurred in the same ranges where the nodules had not been generated.

14

Investigation of particle size distribution of grinded amber by electropulse discharges in a liquid medium

Chornyi Valentyn, Kharchenko Yevhen, Mysiura Taras, Popova Nataliia, Zavialov Volodymyr

Archive of Mechanical Engineering

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2021

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LXVIII, nr 3

337--348

EN

The article presents the study results of electropulse grinding of amber in aqueous and alcoholic media at different amounts of supplied energy. Description of the electropulse grinding laboratory installation, the mechanism of the destruction process of amber particles and methods of statistical processing of experimental data are given. It was established that alcohol medium has a greater impact on the efficiency of crushing than water. Thus, under the same conditions of energy supply, in the aqueous medium the weighted average particle size of amber was 601:6±688:9 μm, and in an alcohol medium – 368:0±269:6 μm. In an aqueous medium, the particle size decreased to 1/13.6 of raw sample, and in an alcoholic medium to 1/22.3 of raw sample compared to the initial size of raw amber. We found that in the aqueous medium the ratio of large to small fractions is mainly the same with the coefficient of alignment of particles with a size of 1.09. In an alcoholic medium, this ratio significantly differs, with the coefficient of alignment of amber particles of a size of 1.67 with the amount of supplied energy of 125 kJ.

15

Experimental and numerical study on the classification of a cyclonic field in a flotation column

Li Xiaoheng, Li Xiao, Yan Xiaokang, Wang Lijun, Zhang Haijun

Physicochemical Problems of Mineral Processing

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2020

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Vol. 56, iss. 3

421--431

EN

The cyclonic-static micro-bubble flotation column (FCSMC) performs well in fine mineral flotation. Compared to traditional flotation columns, its design innovatively introduces a cyclonic structure. The separation of middling and tailing occurs in the cyclonic flow field induced by a cyclonic reversal cone. In this study, the particle size distribution analysis and computational fluid dynamics (CFD) simulations were conducted to reveal the particle distribution law and the classification mechanism in cyclonic flow fields under different circulation pressures. The results showed that particle size showed the same distribution tendency as tangential velocity in the radial direction: both increase from the center and decrease around the wall. As circulation flux increased, the tangential velocity increased, and the particle size differences in the radial direction also increased. The position of the largest particles will move to outside as the largest value of tangential velocity migrates the outward in the radial direction. According to the particle size distribution of the feed, it can be adjusted to the flow field to change the particle distribution, thereby improving the efficiency of separation. This study has an important guiding significance for column design and adjustment of the operating parameters of the flotation process.

16

Evolution of droplet size distribution in selected nebulizers

Dobrowolska Katarzyna, Sosnowski Tomasz R.

Physicochemical Problems of Mineral Processing

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2020

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Vol. 56, iss. 6

32--40

EN

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.

17

Właściwości cementów portlandzkich wieloskładnikowych zawierających granulowany żużel wielkopiecowy, zeolit i wapień

Sanytsky Myroslav, Usherov-Marshak Aleksandr, Kropyvnytska Tetiana, Heviuk Iryna

Cement Wapno Beton

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2020

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R. 25, nr 5

416--427

PL

W pracy przedstawiono wyniki badań wpływu granulowanego żużla wielkopiecowego, naturalnej pucolany [superzeolit] i mączki wapiennej na właściwości cementów wieloskładnikowych. Stwierdzono, że synergiczne połączenie wymienionych dodatków mineralnych, biorąc pod uwagę wpływ rozkładu wielkości cząstek według objętości i powierzchni, a także ustalenie wskaźników wpływu czynników fizycznych, takich jak wodoządność, wydzielanie mleczka, aktywność pucolanowa, ciepło hydratacji na zestaw właściwości zaczynu i betonu: urabialność, wytrzymałość normowa i wczesna, emisja CO2, pozwala uzyskać technologicznie zoptymalizowane cementy portlandzkie wieloskladnikowe. Wyniki wykazały, że oddzielne mielenie poszczególnych składników, optymalizacja składu ziarnowego żużlia, superzeolitu i mączki wapiennej, z uwzględnieniem rozkładu wielkości cząstek według powierzchni, umożliwia wytwarzanie cementu portlandzkiego wieloskładnikowego o dużej wytrzymałości wczesnej CEM II/B-M 42,5 R LH.

EN

The paper presents the results of research on the influence of granulated blast furnace slag, natural pozzolana [superzeolite], and limestone powder on the performance of multi-component cements. It was found that the synergistic combination of mineral additives of different genesis, taking into account the influence of the particle size distribution [PSD] by volume and surface area, as well as the determination of indicators of the influence of physical factors such as water demand, bleeding, pozzolanic activity, the heat of hydration on the set of properties of paste and concrete: workability, standard, and early strength, global warming potential, allows to obtain technologically optimized multi-component Portland cements. The results showed that the production of multi-component Portland cement with high early strength CEM II/B-M 42.5 R-LH ensures separate grinding of individual constituents, optimization of grain composition of slag, superzeolite, and limestone powder taking into account the PSD by surface area.

18

The study of particle size distribution of micronized oat bran layer

Dziki Dariusz, Tarasiuk Wojciech, Łysiak Grzegorz, Jochymek Paweł

Agricultural Engineering

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2020

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Vol. 24, No. 2

45--55

EN

The aim of this work was to study the particle size distribution of micronized oat bran. An impact classified mill was used to pulverizing. Before the pulverizing raw material was sterilized using overheated steam at 150°C during 3.5 min. The moisture of bran after sterilization decreased from 7.2 to about 3.9%. Five speeds of the rotor disc were used: 2600, 2970, 3340, and 3710 rpm. For each speed of the rotor disc the following speeds of classifier wheel were applied: 480, 965, 1450, 1930, 2410 and 2890 rpm. The particle size distribution of oat bran layer was measured by laser light scattering. Moreover, the sense of touch of coarse particles of micronized oat bran on a tongue was assessed according to five point scale. The largest fragmentation of the oat bran was obtained at a disc speed of 3710 rpm and at a classifier rotation speed of 1930 rpm, whereas the most coarse particles were obtained when these parameters were 3340 rpm and 480 rpm, respectively. On the other hand, the highest uniformity in size of particles in size was observed when the lowest speed of disc and classifier were used. Moreover, for the most samples the pulverized particles of oat bran were almost not discernible on tongue.

PL

Celem pracy była analiza składu granulometrycznego zmikronizowanej warstwy owocowo-nasiennej ziarna owsa. Przed rozdrabnianiem surowiec był poddany procesowi sterylizacji parą przegrzaną o temperaturze 150ºC przez 3,5 min. Wilgotność surowca po sterylizacji zmniejszyła się z 7,2 do około 3,9%. Rozdrabnianie przeprowadzono wykorzystując młyn wirnikowy z klasyfikatorem cząstek. Zastosowano cztery prędkości obrotowe wirnika (2600, 2970, 3340, i 3710 obr·min-1). Przy każdej prędkości wirnika stosowano pięć prędkości obrotowych klasyfikatora (480, 965, 1450, 1930, 2410 i 2890 obr·min-1). Skład granulometryczny sproszkowanej okrywy ziarna owsa określono metodą dyfrakcji laserowej. Ponadto przeanalizowano skład chemiczny okrywy i przeprowadzone ocenę sensoryczną wyczuwalności większych jej fragmentów na języku, stosując skalę pięciopunktową. Największy stopień rozdrobnienia okrywy uzyskano przy prędkości wirnika wynoszącej 3710 obr·min-1 oraz przy prędkości klasyfikatora równej 1930 obr·min-1. Natomiast w najgorszym stopniu okrywa ulegała mikronizacji przy prędkości wirnika i klasyfikatora równych odpowiednio 3340 obr·min-1 i 480 obr·min-1. Z kolei największą jednorodność wymiarów uzyskiwano przy najniższych prędkościach wirnika i klasyfikatora. Ponadto dla większości zastosowanych warunków mikronizacji nie stwierdzono podczas oceny sensorycznej obecności grubszych cząstek okrywy na języku.

19

Badanie rozkładu wielkości cząstek zawiesin w wodach opadowych

Wiercik Paweł, Berger Żaneta

LAB Laboratoria, Aparatura, Badania

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2019

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R. 24, nr 2

30--35

PL

Wody opadowe mogą zawierać różnego rodzaju zawiesiny pochodzące bezpośrednio z zanieczyszczonej atmosfery oraz spłukiwane z powierzchni roślin, dachów, ulic. Zawiesiny te mogą występować w postaci stałej, rozpuszczonej lub koloidalnej. Informacje o kształcie, strukturze oraz wielkości i ilości cząstek zawiesin mają znaczenie między innymi przy doborze odpowiednich procesów oczyszczania wód. Celem przeprowadzonych badań było określenie przydatności informacji uzyskanych z granulometru laserowego firmy Malvern dla poznania struktury i wielkości cząstek tworzących polidyspersyjną zawiesinę w wodach opadowych. Próbki wód opadowych w postaci opadu bezpośredniego oraz spływów z dachu pobierano we wsi Szklarka Myślniewska w okresie od grudnia 2017 r. do kwietnia 2018 r. W ujęciu objętościowym w próbkach opadu bezpośredniego dominowały cząstki o średnicach 100-1000 μm, natomiast w ujęciu ilościowym głównie o średnicach 1-10 μm. Większa różnorodność występowała w zawiesinach ze spływów z dachu, co wynikało przede wszystkim z porywania zanieczyszczeń z powierzchni dachu i rynny przez wody opadowe. Zawiesiny we wszystkich próbkach charakteryzowały się różną budową przestrzenną, o czym świadczyły wartości optycznego wymiaru fraktalnego oraz różnymi właściwościami sorpcyjnymi i sedymentacyjnymi (wartości średnich średnic), co wynikało zarówno z rodzaju próbki oraz daty poboru.

20

Eco-efficient blended cements with high volume supplementary cementitious materials

Sanytsky Myroslav, Kropyvnytska Tetiana, Ivashchyshyn Hanna, Rykhlitska Оksana

Budownictwo i Architektura

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2019

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Vol. 18, nr 4

5--14

EN

The ways of reducing CO2 emissions in the cement industry were analysed for the purposes of implementation of the low carbon development strategy. The optimal solution to this problem is the technologically optimised blended cements with high volume of supplementary cementitious materials of various genesis and fineness. The design of eco-friendly blended cements was achieved by a synergistic combination of the main constituents such as granulated blast furnace slag, superfine zeolite, fly ash and limestone, as well as by optimisation of the their granulometric composition, taking into account their bimodal particle size distribution by volume and surface area. Moreover, the article presents the technical, environmental and economic benefits of using eco-efficient blended cements.