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Number of results: 19
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Abstract

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.
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Bibliography

[1] Gurgul, D., Burbelko, A. & Wiktor T. (2021). Derivation of equation for a size distribution of spherical particles in non-transparent materials. Journal of Casting & Materials Engineering. 5(4), 53-60.
[2] Wicksell, S.D. (1925). The corpuscle problem: mathematical study of a biometric problem. Biometric. 17 (1/2), 84-89.
[3] Sheil, E. (1935). Statistische gefügeuntersuchungen I. Zeitschrift für Metallkunde. 27 (9), 199-208.
[4] Schwartz, H.A. (1934). The metallographic determination of the sze distribution of temper carbon nodules. Metals and Alloys. 5, 139-140.
[5] Saltykov, S.A. (1967). The determination of the size distribution of particles in an opaque material from the measurement of the size distribution of their section. in the second international congress for stereology, Chicago, 8-13 April 1967. Berlin–Heidelberg–New York, Springer Verlag.
[6] Cahn, J.W. & Fulmann, R.L. (1956) On the use of lineal analysis for obtaining particle size distributions in opaque samples. Transactions, American Institute of Mining, Metallurgical and Petroleum Engineers. 206, 177-187. [7] Lord, G.W. & Willis, T.F. (1951). Calculation of air bubble size distribution from results of a rosiwal traverse of aerated concrete. ASTM Bulletin. 177, 177-187.
[8] Spektor, A.G. (1950). Analysis of distribution of spherical particles in non-transparent structures. Zavodsk. Lab. 16, 173-177.
[9] https://www.cplusplus.com (date of access 06.06.2021).
[10] Burbelko, A., Gurgul, D., Guzik, E. & Kapturkiewicz, W. (2018). Stereological analysis of the statistical distribution of the size of graphite nodules in DI. Materials Science Forum. 925, 98-103.
[11] Fras, E., Burbelko, A.A. & Lopez, H.F. (1996). Secondary nucleation of eutectic graphite grains. Transactions of the American Foundrymen Society. 104, 1-4.

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Authors and Affiliations

D. Gurgul
1

  1. AGH University of Science and Technology, Kraków, Poland
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Abstract

During the cruise of the research ship r/v Oceania owned by the Institute of Oceanology of the Polish Academy of Sciences in Sopot a research on mineral suspension concentration and dispersion distributions was conducted. The research area included the western part of the Baltic Sea, the Danish Straits, the Norwegian Sea, the waters around Spitsbergen and the North Atlantic Ocean. Samples of water were collected from the surface layer. They were subjected to microscopic analysis. Measurements were done with a projection microscope (magnification lOOOx) and using the Burker's table. After counting the particles dispersion distribution was determined. The largest concentration of mineral suspension was noted offshore in the Norwegian Sea and around Spitsbergen and the smallest in the central Atlantic Ocean.

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Authors and Affiliations

Henryk Gurgul
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Abstract

The article presents a review of the researches on sea and atmospheric physics conducted by the Polish expeditions in Antarctica from 1977 to 1990.

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Authors and Affiliations

Henryk Gurgul
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Abstract

Concentration and dispersion distributions of mineral suspension and crude-oil particles in waters of the Kongsfiord (Spitsbergen) were examined in 1997. Most suspension occurs at glacier margins and decreases towards a fiord outlet.

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Authors and Affiliations

Henryk Gurgul
Waldemar Staroń
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Abstract

This study examines the causal links between improvements in economic freedom and changes in GDP per capita of new EU members in transition in the period 2000‒2009. The empirical results suggest significant causality running from changes in monetary and fiscal freedom, trade openness, regulation of credit, labour, and business, legal structure and security of property rights, and access to sound money to movements in GDP per capita, especially in less and moderately developed CEE transition countries. Moreover, we find evidence that improvements in economic freedom are one of the main factors stimulating the convergence of these economies towards rich EU members. The evidence of causality in the opposite direction is much weaker.

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Authors and Affiliations

Henryk Gurgul
Łukasz Lach
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Abstract

The paper presents validation tests for method which is used for the evaluation of the statistical distribution parameters for 3D particles’ diameters. The tested method, as source data, uses chord sets which are registered from a random cutting plane placed inside a sample space. In the sample space, there were individually generated three sets containing 3D virtual spheres. Each set had different Cumulative Distribution Function (CDF3) of the sphere diameters, namely: constant radius, normal distribution and bimodal distribution as a superposition of two normal distributions. It has been shown that having only a chord set it is possible, by using the tested method, to calculate the mean value of the outer sphere areas. For the sets of data, a chord method generates quite large errors for around 10% of the smallest nodules in the analysed population. With the increase of the nodule radii, the estimation errors decrease. The tested method may be applied to foundry issues e.g. for the estimation of gas pore sizes in castings or for the estimation of nodule graphite sizes in ductile cast iron.

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Authors and Affiliations

D. Gurgul
A. Burbelko
T. Wiktor
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Abstract

The determination of the form of a probability density function (PDF3) of diameters for nodular particles by using a probability density function (PDF2), which form is empirically estimated from cross-sections of these nodules in a metallographic specimen, can be regarded as a special case of Wicksell's corpuscle problem (WCP). The estimation of the PDF3 for the nodular particles provides information about the kinetics of these particles nucleation, and so about the kinetics of their growth. This information is essential for building more accurate mathematical models of the alloy crystallization. In the paper there are presented two derivations of the methods used for the estimation of the PDF3 form. The first method bases on diameters received from a planar cross-section. The second one uses also data from the planar cross-section but not the diameters only chords. Both methods provide practical rules for the analysis of the empirical diameters’ and chord’s size distribution and allow to estimate the mean value of the external surface area of the particles.

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Authors and Affiliations

D. Gurgul
A. Burbelko
T. Wiktor
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Abstract

Recent studies have shown that announcements of information about the
state of the US economy have had a significant impact on European stock
markets. However, the importance of information about the US economy may
vary in time. In order to analyze this issue, we examine the impact of
announcements of unexpected US macroeconomic news on the prices of
selected stocks listed on the Vienna Stocks Exchange. On the basis of
the 5-minute returns of 13 stocks we examine how the strength and the
significance of the reactions of investors to unexpected macroeconomic
news from the US has changed over the last 15 years. Event study
methodology allows us to describe precisely such reactions in the first
minutes after news announcements.
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Authors and Affiliations

Tomasz Wójtowicz
1
Henryk Gurgul
1
Christoph Mitterer
2

  1. Department of Applications of Mathematics in Economics, Faculty of Management, AGH University of Science and Technology, Cracow, Poland
  2. Capital Solutions Advisory GmbH, Graz, Austria
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Abstract

Temperature of superficial water in the Ezcurra Inlet was measured from March 1989 to February 1990, with a use of a mercurial thermometer with accuracy +0.1°C. Temperature was measured usually once a month at selected points. Influence of various factors on temperature of superficial water was preliminarily analysed. Basing on these results, temperature distribution in the mentioned area was determined. Mean yearly temperatures for each station, average space temperatures on measurement days and mean yearly temperatures for the whole area of the Ezcurra Inlet were calculated.

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Authors and Affiliations

Henryk Gurgul
Wiesław Stochmal
Wiesław Szymczak
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Abstract

The mathematical model of the globular eutectic solidification in 2D was designed. Proposed model is based on the Cellular Automaton Finite Differences (CA-FD) calculation method. Model has been used for studies of the primary austenite and of globular eutectic grains growth during the ductile iron solidification in the thin wall casting. Model takes into account, among other things, non-uniform temperature distribution in the casting wall cross-section, kinetics of the austenite and graphite grains nucleation, and non-equilibrium nature of the interphase boundary migration. Calculation of eutectic saturation influence (Sc = 0.9 - 1.1) on microstructure (austenite and graphite fraction, density of austenite and graphite grains) and temperature curves in 2 mm wall ductile iron casting has been done.
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Authors and Affiliations

A.A. Burbelko
M. Górny
D. Gurgul
W. Kapturkiewicz
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Abstract

Characterisation of copy number variation (CNV) and loss of heterozygosity (LOH) has pro- vided evidence for the relationship of this type of genetic variation with the occurrence of a broad spectrum of diseases, including cancer lesions. The role of CNVs and germinal or somatic LOHs in canine mammary tumours is still unknown. Therefore, the aim of this study was to identify CNVs and LOHs in canine mammary tumours. Forty-eight samples obtained from normal (n=24) and tumour (n=24) tissues of dogs were analysed. In the study, we used CanineHD BeadChip assay (Illumina) and OncoSNP software to identify copy number alternations in genomes of dif- ferent dog breeds and in different mammary cancer types occurring in this species. The analyses revealed that, in the case of CNV, the amplification-type variants were longer and more frequent than deletions. Based on the analysis of the frequency of different types of aberrations in the in- dividual parts of the genome, regions that are particularly susceptible to structural aberrations were indicated. The fraction of genes identified within these regions was associated with major processes of neoplastic transformation. Association analysis of such traits as tumour grading as well as the size and age of dogs demonstrated that structural aberrations were more frequent in dogs diagnosed with tumour malignancy grade II and III, in dogs with a larger body size, and in large dogs aged 7-8. The promising results of these pioneering investigations prompt continuation thereof to analyse other types of cancer.

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Authors and Affiliations

M. Surdyka
A. Gurgul
B. Slaska
K. Pawlina
T. Szmatola
M. Bugno-Poniewierska
A. Smiech
K. Kasperek
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Abstract

This article is a description of the progress of research and development in the area of massive large-scale castings - slag ladles implemented in cooperation with the Faculty of Foundry Engineering of UST in Krakow. Slag ladles are the one of the major castings that has been developed by the Krakodlew (massive castings foundry) for many years. Quality requirements are constantly increasing in relation to the slag ladles. Slag ladles are an integral tool in the logistics of enterprises in the metallurgical industry in the process of well-organized slag management and other by-products and input materials. The need to increase the volume of slag ladles is still growing. Metallurgical production is expected to be achieved in Poland by 2022 at the level of 9.4 million Mg/year for the baseline scenario - 2016 - 9 million Mg/year. This article describes the research work carried out to date in the field of technology for the production of massive slag ladles of ductile cast iron and cast steel.

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Authors and Affiliations

M. Paszkiewicz
Edward Guzik
ORCID: ORCID
D. Kopyciński
ORCID: ORCID
Barbara Kalandyk
ORCID: ORCID
A. Burbelko
ORCID: ORCID
D. Gurgul
S. Sobula
ORCID: ORCID
A. Ziółko
K. Piotrowski
ORCID: ORCID
P. Bednarczyk

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