Nine samples of basic (dolerite, gabbro) intrusions collected at Bellsund, South Spitsbergen, have been K−Ar dated. Three dates, between 87.8 and 102.9 Ma, obtained from dolerite sills which intrude Carboniferous and Permian deposits in Van Keulenfjorden point to a Cretaceous age of intrusive activity (Diabasodden Suite). The K−Ar dates obtained from dolerite and gabbro which intrude Upper Proterozoic metasedimentary terrane of Chamber− lindalen form two groups: the dates between 97.1 and 178.6 Ma point to a Mesozoic age of the intrusions (Diabasodden Suite); the dates from a tectonized gabbroid (280.9–402.0 Ma) might point to a Late Palaeozoic age of the intrusion. No K−Ar dates which would indicate a Proterozoic age of the basic intrusions were obtained
Henryk Elzenberg ewoluował od racjonalizmu i zachwytu logiką do radykalnej opozycji wobec scjentyzmu i „biurokratów ścisłości” ze szkoły lwowsko-warszawskiej. W obecnej filozofii akademickiej istnieje nieszczęśliwy ostry podział na filozofię analityczną i tzw. kontynentalną. Czy tę filozofię nieanalityczną da się określić w sposób pozytywny? Zasugerowanych jest kilka pomysłów, ale żaden nie wydaje się dostatecznie dobry. Czy ten podział da się przezwyciężyć? Niektórzy usiłują, np. Hilary Putnam i Alain Badiou, chociaż Putnam nie próbuje syntezy, a Badiou próbuje, ale rezultat jego działań rozczarowuje i nie jest wolny od błędów, gdy filozof powołuje się na zaawansowaną logikę matematyczną. W każdym razie filozofia musi funkcjonować pomiędzy dwoma biegunami: naukowym, logicznym i humanistycznym, literackim. W naszych czasach nowym źródłem doświadczeń powinny być dla filozofii komputery. Możliwość cyfrowej symulacji każe na nowo rozważyć pytanie o specyfikę człowieka. W tej dziedzinie oba podejścia do filozofii stają się niezbędne. Przykładem uwzględnienia zarówno logiki, jak i filozofii dialogu jest zaproponowane wcześniej przez autora ostateczne wzmocnienie Testu Turinga, czyli eksperyment myślowy, w którym dziecko jest od urodzenia wychowywane przez roboty i ma się okazać, czy tak ukształtowany człowiek okaże się w miarę „normalny”.
In this paper, two new sinusoidal signal frequency estimators calculated on the basis of four equally spaced signal samples are presented. These estimators are called four-point estimators. Simulation and experimental research consisting in signal frequency estimation using the invented estimators have been carried out. Simulation has also been performed for frequency tracking. The simulation research was carried out applying the MathCAD computer program that determined samples of a sinusoidal signal disturbed by Gaussian noise. In the experimental research, sinusoidal signal samples were obtained by means of a National Instruments PCI-6024E data acquisition card and an Agilent 33220A function generator. On the basis of the collected samples, the values of four-point estimators invented by the authors and, for comparison, the values of three- and four-point estimators proposed by Vizireanu were determined. Next, estimation errors of the signal frequency were determined. It has been shown that the invented estimators can estimate a signal frequency with greater accuracy.
The subject of the paper is structural stability of the Zn-26 wt.% Al binary alloys doped with 2.2 wt.% Cu or 1.6 wt.% Ti addition. The structural stability of Zn-Al alloys with increased Al content is connected with stability of solid solution of zinc in aluminium α', which is the main component of these alloys microstructure. Such a solution undergoes phase transformations which are accompanied, among others, by changes in dimensions and strength properties. The structural stability of the ZnAL26Cu2.2 and ZnAl26Ti1.6 alloys was investigated using XRD examinations during long term natural ageing after casting, as well as during long term natural ageing after super-saturation and quenching. On the basis of the performed examinations it was stated that small Ti addition to the binary ZnAl25 alloy, apart from structure refinement, accelerates decomposition of the primary α' phase giving stable structure in a shorter period of time in comparison with the alloy without Ti addition. Addition of Ti in amount of 1.6 wt.%, totally replacing Cu, allows obtaining stable structure and dimensions and allows avoiding structural instability caused by the metastable ε−CuZn4 phase present in the ZnAl26Cu2.2 alloy.
The paper presents results of measuring attenuation coefficient of the Al-20 wt.% Zn alloy (AlZn20) inoculated with different grain refiners. During experiments the melted alloys were doped with Al-Ti3-C0.15 refining master alloy. Basing on measurements performed by Krautkramer USLT2000 device with 1MHz ultrasound wave frequency it was stated that grain refinement reduces the attenuation coefficient by about 20-25%. However, the examined alloys can be still classified as the high-damping ones of attenuation greater than 150 dB/m.
The paper presents relationships between the degree of structure fineness and feeding quality of the Al – 20 wt.% Zn (Al-20 Zn) alloy cast into a mould made from sand containing silica quartz as a matrix and bentonite as a binder, and its damping coefficient of the ultrasound wave at frequency of 1 MHz. The structure of the examined alloy was grain refined by the addition of the refining Al-3 wt.% Ti – 0.15 wt.%C (TiCAl) master alloy. The macrostructure analysis of the initial alloy without the addition of Ti and the alloy doped with 50-100 ppm Ti as well as results of damping experiments showed that the structure of the modified alloy is significantly refined. At the same time, its damping coefficient decreases by about 20-25%; however, it still belongs to the so called high-damping alloys. Additionally, it was found that despite of using high purity metals Al and Zn (minimum 99,99% purity), differences in the damping coefficient for samples cut from upper and bottom parts of the vertically cast rolls were observed. These differences are connected with the insufficient feeding process leading to shrinkage porosity as well as gases present in metal charges which are responsible for bubbles of gas-porosity.
The paper is devoted to grain-refinement of the medium-aluminium zinc based alloys (MAl-Zn). The system examined was sand cast Zn10 wt. %. Al binary alloy (Zn-10Al) doped with commercial Al-3 wt. % Ti – 0.15 wt. % C grain refiner (Al-3Ti-0.15C GR). Basing on the measured attenuation coefficient of ultrasonic wave it was stated that together with significantly increased structure fineness damping decreases only by about 10 – 20%. The following examinations should establish the influence of the mentioned grain-refinement on strength and ductility of MAl-Zn cast alloys.
Radiometric and geochemical studies were carried out at Red Hill in the southern part of King George Island (South Shetland Islands, northern Antarctic Peninsula) on the Bransfield Strait coast. The rock succession at Red Hill has been determined to represent the Baranowski Glacier Group that was previously assigned a Late Cretaceous age. Two formations were distinguished within this succession: the lower Llano Point Formation and the upper Zamek Formation. These formations have stratotypes defined further to the north on the western coast of Admiralty Bay. On Red Hill the Llano Point Formation consists of terrestrial lavas and pyroclastic breccia; the Zamek Formation consist predominantly of fine to coarse tuff, pyroclastic breccia, lavas, tuffaceous mud− , silt−, and sandstone, locally conglomeratic. The lower part of the Zamek Formation contains plant detritus (Nothofagus , dicotyledonous, thermophilous ferns) and numerous coal seams (vitrinitic composition) that confirm the abundance of vegetation on stratovolcanic slopes and surrounding lowlands at that time. Selected basic to intermediate igneous rocks from the succession have been analysed for the whole−rock K−Ar age determination. The obtained results indicate that the Red Hill succession was formed in two stages: (1) from about 51–50 Ma; and (2) 46–42 Ma, i.e. during the Early to Middle Eocene. This, in combination with other data obtained from other Baranowski Glacier Group exposures on western coast of Admiralty Bay, confirms the recently defined position of the volcano−clastic succession in the stratigraphic scheme of King George Island. The new stratigraphic position and lithofacies development of the Red Hill succession strongly suggest its correlation with other Eocene formations containing fossil plants and coal seams that commonly occur on King George Island.
The paper presents results of measuring heat diffusivity and thermal conductivity coefficients of used green foundry sand in temperature range ambient – 600 o C. During the experiments a technical purity Cu plate was cast into the green-sand moulds. Basing on measurements of the mould temperature field during the solidification of the casting, the temperature relationships of the measured properties were evaluated. It was confirmed that the obtained relationships are complex and that water vaporization strongly influences thermal conductivity of the moulding sand in the first period of the mould heating by the poured and solidified casting
The paper presents results of measuring thermal conductivity and heat capacity of bentonite foundry sand in temperature range ambient – 900 OC. During the experiments a technical purity Cu plate was cast into the green-sand moulds. Basing on measurements of the mould temperature field during the solidification of the casting, the temperature relationships of the measured properties were evaluated. It was confirmed that water vaporization strongly influences thermal conductivity of the moulding sand in the first period of the mould heating by the poured casting.