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Wyszukujesz frazę "Kozlowski, S." wg kryterium: Autor


Wyświetlanie 1-6 z 6
Tytuł:
Regressive-transgressive cyclothem with facies record of the re-flooding window in the Late Silurian carbonate succession (Podolia, Ukraine)
Autorzy:
Łuczyński, P.
Kozłowski, W.
Skompski, S.
Powiązania:
https://bibliotekanauki.pl/articles/138684.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
re-flooding window
spectral gamma ray record
shallow water carbonates
late Silurian
Podolia
wody płytkie
węglan
sylur
Podole
Opis:
The term “re-flooding window” was recently proposed as a time-interval connected with the transgressive stage of present day peri-reefal development. In the analysis presented here, a fossil record of a re-flooding window has been recognized. Nine Late Silurian carbonate sections exposed on the banks of the Dnister River in Podolia (Ukraine) have been correlated base on bed-by-bed microfacies analysis and spectral gamma ray (SGR) measurements. Correlated were sections representing settings ranging from the inner part of a shallow-water carbonate platform to its slope, through an organic buildup. The reconstructed depositional scenario has been divided into six development stages, with the first three representing a regressive interval and the latter three a transgressive interval of the basin’s history. The re-flooding window has been identified at the beginning of a transgressive part of the succession. Surprisingly, it is characterized by an extremely fast growth of a shallow, tide-dominated platform and by deposition of calciturbiditic layers in a more basinal area. The interpreted succession is a small-scale model illustrating the reaction of carbonate depositional sub-environments to sea level changes and determining the facies position of the stromatoporoid buildups within the facies pattern on a Silurian shelf. The use of SGR analyses in shallow water, partly high-energy, carbonate facies, both for correlation purposes and for identifying depositional systems, is a relatively new method, and thus can serve as a reference for other studies of similar facies assortment.
Źródło:
Acta Geologica Polonica; 2015, 65, 3; 297-318
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stromatoporoid beds and flat-pebble conglomerates interpreted as tsunami deposits in the Upper Silurian of Podolia, Ukraine
Autorzy:
Łuczyński, P.
Skompski, S.
Kozłowski, W.
Powiązania:
https://bibliotekanauki.pl/articles/138749.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Palaeotsunami
Silurian
Podolia
Stromatoporoid beds
Flat-pebble conglomerates
sylur
Podole
warstwy stromatoporoidowe
prefabrykaty płaskie
Opis:
Tsunami deposits are currently a subject of intensive studies. Tsunamis must have occurred in the geological past in the same frequency as nowadays, yet their identified depositional record is surprisingly scarce. Here we describe a hitherto unrecognized example of probable palaeotsunamites. The Upper Silurian (Pridoli) carbonate succession of Podolia (southwestern Ukraine) contains variously developed event beds forming intercalations within peritidal deposits (shallow water limestones, nodular marls and dolomites). The event beds are represented by stromatoporoid and fine-grained bioclastic limestones, in some places accompanied by flat-pebble conglomerates. The interval with event beds can be traced along the Zbruch River in separate outcrops over a distance of more than 20 km along a transect oblique to the palaeoshoreline. The stromatoporoid beds have erosional bottom surfaces and are composed of overturned and often fragmented massive skeletons. The material has been transported landward from their offshore habitats and deposited in lagoonal settings. The flat-pebble conglomerates are composed of sub-angular micritic clasts that are lithologically identical to the sediments forming the underlying beds. Large-scale landward transport of the biogenic material has to be attributed to phenomena with very high energy levels, such as tropical hurricanes or tsunamis. This paper presents a tsunamigenic interpretation. Morphometric features of redeposited stromatoporoids point to a calm original growth environment at depths well below storm wave base. Tsunami waves are the most probable factor that could cause their redeposition from such a setting. The vastness of the area covered by parabiostromal stromatoporoid beds resembles the distribution of modern tsunami deposits in offshore settings. The stromatoporoid beds with unsorted stromatoporoids of various dimensions evenly distributed throughout the thickness of the beds and with clast-supported textures most probably represent deposition by traction. In some sections, the stromatoporoids are restricted to the lowermost parts of the beds, which pass upwards into bioclastic limestones. In this case, the finer material was deposited from suspension. The coexistence of stromatoporoid beds and flat-pebble conglomerates also allows presenting a tsunami interpretation of the latter. The propagating tsunami waves, led to erosion of partly lithified thin-layered mudstones, their fragmentation into flat clasts and redeposition as flat-pebble conglomerates.
Źródło:
Acta Geologica Polonica; 2014, 64, 3; 261-280
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Recent studies on the Silurian of the western part of Ukraine
Autorzy:
Łuczyński, P.
Skompski, S.
Kozłowski, W.
Powiązania:
https://bibliotekanauki.pl/articles/138934.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Upper Silurian
Podolia
facies
stromatoporoid beds
sedimentary environments
górny sylur
Podole
facja
warstwy stromatoporoidowe
środowiska sedymentacyjne
Opis:
The paper summarises the effects of recent studies carried out by a team from the Department of Historical and Regional Geology of the Faculty of Geology, University of Warsaw on the upper Silurian of Podolia (western part of Ukraine). The sedimentary history of the Silurian succession of Podolia is characterised by its cyclic pattern, with shallowing-upward cyclothems. In the traditional interpretation, the occurrence of stromatoporoid beds within each cyclothem marks the deepest (or most open-marine) sedimentary environment within the cycle. According to the results of recent studies, their occurrence is connected rather with a relatively shallow-water environment and with high energy phenomena. A substantial reinterpretation of the main sedimentary processes governing the deposition and facies distribution on the shelf is presented. Particularly, there are recognised and described high-energy sedimentary events repeatedly punctuating the generally calm sedimentation that prevailed in the lagoonal settings, some of which are interpreted as tsunami induced. Further perspectives for studies on the Silurian successions of Podolia are also discussed. The main problem is the precise correlation of particular sections that are scattered over vast distances and developed in similar facies associations.
Źródło:
Acta Geologica Polonica; 2016, 66, 3; 281-297
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Secondary steel refining for continuous sequence bloom casting for high oxide cleanness final products
Rafinacja pozapiecowa ciekłej stali do ciągłego sekwencyjnego odlewania z przeznaczeniem na wyroby o dużej czystości tlenkowej
Autorzy:
Zdonek, B.
Szypuła, I.
Kozłowski, J.
Szczęch, S.
Powiązania:
https://bibliotekanauki.pl/articles/354603.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
rafinacja
czystość tlenkowa
odlewanie sekwencyjne
secondary refining
oxide cleanness
sequence continuous casting
Opis:
Steelmaking and secondary refining process technology of resulphurized liquid steel with low content of total oxygen, assigned for continuous casting of strands for rolled and forged products for automotive industry was developed. The influence of secondary steel refining parameters on total oxygen content as well as amount and morphology of non-metallic inclusions was examined. It was found, that content of total oxygen and amount of non-metallic inclusions in steel decrease as steel refining time in the ladle becomes longer, and the chemical composition of non-metallic inclusions in steel changes from modified calcium aluminates to spinel inclusion of CaOźAl2O3źMgO type. The total oxygen content in steel from continuous casting in four cast sequence ranged from 6 to 25 ppm, with percentage share of non-metallic inclusions from 0.09 to 0.30 per cent and equivalent diameter 0.78 to 1.59 µm.
Opracowano technologię wytapiania i rafinacji pozapiecowej ciekłej stali z regulowaną zawartością siarki, z niską zawartością tlenu całkowitego, przeznaczoną do odlewania w sekwencji wlewków ciągłych na wyroby walcowane i kute dla przemysłu motoryzacyjnego. Zbadano wpływ parametrów technologicznych rafinacji pozapiecowej stali na zawartość tlenu całkowitego oraz na ilość i morfologię wtrąceń niemetalicznych. Stwierdzono, że zawartość tlenu całkowitego w stali oraz liczność wtrąceń niemetalicznych zmniejszają się w miarę wydłużania czasu rafinacji stali w kadzi, a skład chemiczny wtrąceń niemetalicznych zmienia się ze zmodyfikowanych glinianów wapnia we wtrącenia spinelowe typu CaOźAl2O3ź MgO. Zawartości tlenu całkowitego w stali odlewanej w cztero wytopowej sekwencji wynosiły od 6 do 25 ppm, przy procentowym udziale wtrąceń niemetalicznych - od 0,09 do 0,30 % i średnicy równoważnej od 0,78 do 1,59 µm.
Źródło:
Archives of Metallurgy and Materials; 2012, 57, 1; 347-353
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magmatic and post-magmatic phenomena in the Karkonosze granite and its metamorphic envelope (West Sudetes, SW Poland)
Autorzy:
Kozłowski, A.
Ilnicki, S.
Matyszczak, W.
Marcinowska, A.
Powiązania:
https://bibliotekanauki.pl/articles/138848.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Karkonosze pluton
melt inclusions
fluid inclusions
Nb-Ta-REE pegmatites
contact zone amphibolites
pluton Karkonoszy
inkluzje stopu
ciekłe inkluzje
pegmatyt
Opis:
Mineralogical studies of the Karkonosze granite (ca. 322–312 Ma) and its surroundings in West Sudetes (SW Poland) have provided data on Nb-Ta-REE minerals from pegmatites in the NE part of the pluton and several new finds of Ag minerals and 15 oxygenic Bi phases, hitherto not reported from the massif. The Karkonosze pegmatites are enriched in HREE as fergusonite-(Y) or xenotime-(Y) appear in almost every studied pegmatite, together with a subordinate assemblage of the aeschynite, euxenite or columbite group. The abundance of LREE minerals such as allanite-(Ce) and the monazite group, correlates inversely with the Nb-Ta-Ti minerals, whilst an early generation of monazite-(Ce) revealed an exceptionally high amount of Nd (up to 22 wt.% of Nd2O3). The physical and chemical conditions during the magmatic and post-magmatic processes were reconstructed and the effects of contact metamorphism in amphibolites from hornfelsed zones examined. Changes in solution composition and concentration at the early magmatic stage (825–920ºC), pegmatitic stage overlapping with hydrothermal (560°C which ended at 160–90°C) and clearly hydrothermal stage (400 to 110°C) were studied in detail by means of melt and fluid inclusions in quartz. Furthermore, post-magmatic fluids, including some enriched in Li and B, were identified in rock-forming quartz from the whole pluton. In turn, study of the amphibolites indicates that the pair cummingtonite + anorthite or the presence of Ca-rich plagioclase with actinolite seem to be reliable mineral proxies of the thermal impact of the granitoid body on amphibolites in its envelope. The inferred conditions of the contact processes (450–550°C, 2.5–4.8 kbar) point to an elevated geothermal gradient (ca. 32–45°C/km) probably reflecting the heat flow induced by the Karkonosze intrusion. Moreover, despite the textural and mineral changes imposed by regional and contact metamorphism, the amphibolites have their pre-metamorphic (magmatic) geochemical features undisturbed.
Źródło:
Acta Geologica Polonica; 2016, 66, 3; 451-471
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thresholding techniques for segmentation of atherosclerotic plaque and lumen areas in vascular arteries
Autorzy:
Markiewicz, T.
Dziekiewicz, M.
Osowski, S.
Maruszyński, M.
Kozłowski, W.
Bogusławska-Walecka, R.
Powiązania:
https://bibliotekanauki.pl/articles/201734.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
image processing
thresholding methods
computed tomography
vascular image parameterization
przetwarzanie obrazu
metody progowania
tomografia komputerowa
Opis:
The paper develops the automatic methods of segmentation of the blood vessel area in the images of the multi-slice computed tomography, allowing to separate the lumen from the atherosclerotic plaque areas. The solution is based on the application of different implementations of thresholding, including between class variance in a bimodal mode, Gaussian mixture modeling, clustering technique, polynomial and multilayer perceptron approximations. These methods are compared with many examples of arteries of different percentage of the plaque occupancy in the iliac and femoral arteries. The numerical results of segmentation have been verified by the medical experts and prove its usefulness in medical practice. The presented system can find application in an automatic evaluation of the atherosclerosis progression/regression of patients on the basis of sequence of Computed Tomography slice images.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2015, 63, 1; 269-280
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-6 z 6

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