Autor: Niezgoda, H. - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Respiration and assimilation processes reflected in the carbon isotopic composition of atmospheric carbon dioxide
Autorzy:: Szaran, J.
Niezgoda, H.
Trembaczowski, A.
Powiązania:: https://bibliotekanauki.pl/articles/146953.pdf
Data publikacji:: 2002
Wydawca:: Instytut Chemii i Techniki Jądrowej
Tematy:: atmosphere
carbon dioxide
carbon isotopes
delta-C-13
respiration
Opis:: This paper presents diurnal variations of concentration and carbon isotopic composition of atmospheric carbon dioxide caused by respiration and assimilation processes. Air samples were collected during early and late summer in 1998 in unpolluted area (village Guciow located near the Roztocze National Park, SE Poland) in three different environments: uncultivated field on a hill, a meadow in the Wieprz river valley and a forest. The effect is very strong during intensive vegetation growth on a sunny day and clear night. The largest diurnal variations in atmospheric CO2 concentration and its carbon isotopic composition in June above the meadow were about 480 ppm and 10‰, respectively.
Źródło:: Nukleonika; 2002, 47,suppl.1; 59-61
0029-5922
1508-5791
Pojawia się w:: Nukleonika
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Diurnal variations and vertical distribution of δ13C, and concentration of atmospheric and soil CO2 in a meadow site, SE Poland
Autorzy:: Szaran, J.
Dudziak, A.
Trembaczowski, A.
Niezgoda, H.
Hałas, S.
Powiązania:: https://bibliotekanauki.pl/articles/2058901.pdf
Data publikacji:: 2005
Wydawca:: Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:: SE Poland
atmospheric CO2
carbon dioxide concentration
diurnal observations
delta 13C
soil CO2
Opis:: We provide the results of 24-hour observations made in a meadow site located in a small river valley in Central Europe. Samples of atmospheric air were taken from three horizons: near the soil (0.05 m), in the grass (0.5 m) and above the meadow (2 m) at two-hour intervals. At the same time, samples of soil air were collected from two horizons: -0.1 and -0.5 m. We have found a variation of δ¹³C above the ground from -6‰ during the day to -20‰ late at night accompanied by variations in CO₂ concentration from 270 ppm during the day, to various levels late at night at different heights above the ground. The maximum concentration was 1430 ppm at the ground level. The correlation coefficient between δ¹³C and reciprocal of concentration was the highest (R2 = 0.984) for the samples collected 2 m above the ground, the regression line clearly indicating CO₂ mixing from the two sources: atmospheric and biogenic reservoirs. The intercept of the mixing line yields δC = -23.0‰ for the biogenic CO₂. In contrast, the diurnal variations in the soil were relatively small, δ¹³C varied from -21.6 to -23.4‰, while CO₂ concentration from 4300 to 8200 and from 24 700 to 34 500 ppm at depths of 0.1 m and 0.5 m respectively, which is less than 2-fold. Small diurnal variations are characteristic of dry soils, where δ^13C is weakly correlated with CO₂ concentration (in our case R2 was 0.30 and 0.54, respectively).
Źródło:: Geological Quarterly; 2005, 49, 2; 135--144
1641-7291
Pojawia się w:: Geological Quarterly
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Thermal-mechanical coupled simulation
Autorzy:: Nguyen, H. P.
Derewońko, A.
Niezgoda, T.
Powiązania:: https://bibliotekanauki.pl/articles/244229.pdf
Data publikacji:: 2015
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: thermo-mechanical coupled
simulation
plastic deformation
Opis:: Optimal design of engineering structures and technological processes requires taking into account various factors affecting the state of strain and stresses in the structure. Coupled thermo-mechanical analysis enables, among others, determination of undesirable changes in a body shape resulting from the implementation method of the initially-boundary conditions, for example, time-varying load and physical properties of the material depending on the temperature. They are also used to determine residual stresses remaining after manufacturing to prevent revalued stiffness and rigidity of the designed construction. In this study, coupled thermo-mechanical analysis illustrated by metal machining operation is presented. The commercial code MSC.Marc has been used to develop a coupled thermo-mechanical finite element model of plane-stress orthogonal metal cutting operations. Metal cutting is one of the most important and common manufacturing processes in the car industry. A thermal mechanical transient analysis is performed to convert mechanical work into heat by plastic deformation of the workpiece material and friction during metal machining operation. The finite element mesh distortion, due to large deformations, requires a remesh technique. The influence of parameters of the 2D and 3D finite element mesh adaptation on plastic deformation and temperature generated in the cutting processing is considered.
Źródło:: Journal of KONES; 2015, 22, 3; 161-168
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Numerical analysis of rod uniaxial tension considering thermo-mechanical coupling effect
Numeryczna analiza jednoosiowego rozciągania pręta z uwzględnieniem efektu sprzężenia termomechanicznego
Autorzy:: Nguyen, H. P.
Niezgoda, T.
Derewońko, A.
Jachimowicz, J.
Powiązania:: https://bibliotekanauki.pl/articles/263858.pdf
Data publikacji:: 2015
Wydawca:: Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:: thermo-mechanical coupling
uniaxial tension
finite element method
sprzężenie termomechaniczne
jednoosiowe rozciąganie
metoda elementów skończonych
Opis:: This paper presents numerical analyses of uniaxial tension tests on rods made of a material with elastic-plastic characteristics with mapping the temperature fields generated in the fields of plastic strains. The use of thermo-mechanical coupling algorithms implemented in CAE programs that enable us to enter the parameters of materials dependent on temperature and used to visualize the damage of the samples is presented. The numerical models were validated with experimental research.
W pracy przedstawiono analizy numeryczne testów jednoosiowego rozciągania prętów wykonanych z materiału o charakterystyce sprężysto-plastycznej z odwzorowaniem pól temperatury generowanych w obszarach odkształceń trwałych. Zaprezentowano wykorzystanie algorytmów sprzężenia termomechanicznego zaimplementowanych w programach CAE, umożliwiających wprowadzenie parametrów materiałów zależnych od temperatury oraz stosowanych do wizualizacji zniszczenia próbek. Wyniki symulacji zwalidowano badaniami eksperymentalnymi.
Źródło:: Metallurgy and Foundry Engineering; 2015, 41, 4; 189-199
1230-2325
2300-8377
Pojawia się w:: Metallurgy and Foundry Engineering
Dostawca treści:: Biblioteka Nauki

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