Wyniki wyszukiwania - BazTech

1

Some new generalizations of Maroni inequality on time scales

Yin L., Zhao C.

Demonstratio Mathematica

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2013

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Vol. 46, nr 4

645--654

EN

The aim of present paper is to establish some new integral inequalities on time scales involving several functions and their derivatives which in the special cases yield the well known Maroni inequality and some of its generalizations.

2

Nowe wyzwania w hydrogeologii – europejski projekt FP7 GENESIS

Witczak S., Kania J., Malina G., Postawa A., Żurek A., Duliński M., Różański K., Wachniew P., Nikiel G.

Biuletyn Państwowego Instytutu Geologicznego

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2013

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nr 456 Hydrogeologia z. 14/2

633--643

PL

W artykule krótko przedstawiono charakterystykę europejskiego projektu FP-7 GENESIS oraz doświadczenia wynikające z badania polskich obszarów testowych włączonych do projektu. W zrozumieniu systemu krążenia wód podziemnych najważniejsza jest rola skali czasowej oraz ocena środowiskowej roli wody. W prezentacji skali czasowej bardzo ważne są proste modele konceptualne. Bardziej zaawansowane modelowanie numeryczne wymaga nowych metod ograniczających niepewność prognoz. Jedną z przedstawionych w artykule metod jest kalibracja modeli przepływu i transportu przy pomocy znaczników środowiskowych w kolejnych krokach zależnych od dostępnych danych oraz przedziałów wieków wody.

EN

The paper briefly describes the European FP7 project GENESIS and lessons learned from the Polish case studies involved into the project. The most important are the role of time scales in understanding the groundwater flow system and environmental water requirements. Simple conceptual models are very important for time scale presentation. More sophisticated numerical modeling needs new methods of uncertainty control. One of them shown in the paper is calibration of flow and transport models with the aid of tracers in steps related to available data and age ranges.

3

On some aspects of multiple scale method in problems of nonlinear dynamics

Awrejcewicz J., Starosta R., Sypniewska-Kamińska G.

Vibrations in Physical Systems

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2012

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Vol. 25

53--58

EN

Nonlinear vibrations of the two degree-of-freedom system near resonances are studied. The system is externally and kinematically driven. The dynamical problem is solved by an analytical multiple scales method (MS). This analytical approach gives very good results in solving problems of nonlinear dynamics and is more and more popular in last decades. The investigations are focused on correctness of MS method using various number of considered time scales. Namely, we show that in some cases the use of only two time scales is insufficient to detect all possible resonances exhibited by the studied system.

4

Null-Controllability of Linear Systems on Time Scales

Pawłuszewicz E.

Acta Mechanica et Automatica

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2012

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Vol. 6, no. 4

50-55

EN

The purpose of the paper is to study the problem of controllability of linear control systems with control constrains, defined on a time scale. The obtained results extend the existing ones on any time domain. The set of values of admissible controls is a given closed and convex cone with nonempty interior and vertex at zero or is a subset of containing zero.

5

Czasowe i przestrzenne skale turbulencji w mieszalniku wielostopniowym

Talaga J.

Czasopismo Techniczne. Mechanika

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2008

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R. 105, z. 2-M

351-360

PL

W pracy przedstawiono wyniki badań doświadczalnych, których celem było określenie czasowych i przestrzennych mikroskal i makroskal turbulencji cieczy w mieszalniku wielostopniowym z dwoma mieszadłami usytuowanymi na wspólnym wale. Wielkości te wyznaczano w oparciu o funkcję autokorelacji prędkości fluktuacyjnych, uzyskaną na podstawie wyników pomiarów chwilowych prędkości przepływu cieczy w mieszalniku. Wyznaczone wielkości skal turbulencji porównano dla sześciu różnych kombinacji dwóch mieszadeł na wale oraz dla różnych odległości między mieszadłami.

EN

In the paper the results of investigations of time and length turbulence macro and micro scales for mixing vessel with multiple impellers are presented. These quantities were determined on the ground of the autocorrelation function of rms velocities, calculated on the basis of instantaneous velocities of flow in the mixing vessel. The values of turbulence scales obtained were compared for six different configurations of dual-impeller systems and different distances between impellers.

6

Short reversals of the earth’s magnetic field and its relative paleointensity variations as chronostratigraphic tools - perspectives and limitations

Nowaczyk Norbert R.

Geologos

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2000

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Vol. 5

5--12

EN

Geomagnetic variations in direction as well as in intensity throughout the geologic history as documented in the remanent magnetization of sediment successions generally offer a potential (the investigations are performed in correlation) for dating of these sediments. Therefore, magnetostratigraphic investigations are performed in order to monitor geomagnetic fluctuations and to correlate them to established reference datasets such as the geomagnetic polarity time scale. The last major reversal of the earth’s magnetic field occured at about 780 ka. Since then, a quite large number of so-called reversal excursions with a duration of a few thousand years interrupted the normal polarity phase of the geomagnetic field, known as the ’Brunhes Chron’, about each 50 to 100 kyr. According to absolute as well as relative paleointensity determinations the field intensity throughout the Brunhes Chron was not constant but variable at least within the range of one order of magnitude. Especially reversal excursions, as expressed by magnetization directions differing largely from the expected dipole direction for a certain site, are associated with pronounced lows in the field intensity. So, in principle, determination of the sediment’s magnetization in terms of direction and intensity of time-calibrated curves can provide a detailed age model of (late) Quaternary sediments.