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Wyszukujesz frazę "frozen soils" wg kryterium: Temat


Wyświetlanie 1-2 z 2
Tytuł:
Effect of carbon and nitrogen addition on nitrous oxide and carbon dioxide fluxes from thawing forest soils
Autorzy:
Haohao, Wu
Xingkai, Xu
Cuntao, Duan
TuanSheng, Li
Weiguo, Cheng
Powiązania:
https://bibliotekanauki.pl/articles/972995.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
carbon dioxide
glucose
interactive effect
nitrous oxide
n sources
frozen soils
Opis:
Packed soil-core incubation experiments were done to study the effects of carbon (glucose, 6.4 g C m-2) and nitrogen (NH4Cl and KNO3, 4.5 g N m-2) addition on nitrous oxide (N2O) and carbon dioxide (CO2) fluxes during thawing of frozen soils under two forest stands (broadleaf and Korean pine mixed forest and white birch forest) with two moisture levels (55 and 80% water-filled pore space). With increasing soil moisture, the magnitude and longevity of the flush N2O flux from forest soils was enhanced during the early period of thawing, which was accompanied by great NO3--N consumption. Without N addition, the glucose-induced cumulative CO2 fluxes ranged from 9.61 to 13.49 g CO2-C m-2, which was larger than the dose of carbon added as glucose. The single addition of glucose increased microbial biomass carbon but slightly affected soil dissolved organic carbon pool. Thus, the extra carbon released upon addition of glucose can result from the decomposition of soil native organic carbon. The glucose-induced N2O and CO2 fluxes were both significantly correlated to the glucose-induced total N and dissolved organic carbon pools and influenced singly and interactively by soil moisture and KNO3 addition. The interactive effects of glucose and nitrogen inputs on N2O and CO2 fluxes from forest soils after frost depended on N sources, soil moisture, and vegetation types.
Źródło:
International Agrophysics; 2017, 31, 3; 339-349
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of thermophysical properties of frozen soil on the temperature of the cast-in-place concrete pile in a negative temperature environment
Autorzy:
Liu, Ziying
Yu, Tianlai
Yan, Ning
Gu, Lipeng
Powiązania:
https://bibliotekanauki.pl/articles/27312226.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
thermal properties
frozen soils
cast-in-place
concrete pile
negative temperature environment
ice
permafrost
heat conductivity coefficient
Opis:
Thermophysical properties of frozen soil have a great influence on the quality of cast-in-place concrete piles. In this paper, the embedded concrete temperature monitoring system is used to test the variation law of the concrete temperature during the construction of the bored pile. Thermophysical properties of permafrost around piles are tested. Based on the theory of three-phase unsteady heat conduction of soil, the influence of specific heat capacity, thermal conductivity, thermal diffusivity, and latent heat of phase transformation on the temperature change of a concrete pile is systematically studied. The thermal parameter is obtained which exerts the most significant influence on the temperature field. According to the influence degree of frozen soil on pile temperature, the order from high to low is thermal conductivity, thermal diffusivity, latent heat of phase change, and specific heat capacity. The changes in pile wall temperature caused by the change of these properties range between 2.60–10.97◦C, 1.49– 9.39◦C, 2.16–2.36◦C, and 0.24–3.45◦C, respectively. The change percentages of parameters vary between 35.77–47.12%, 12.22–40.20%, 12.46–32.25%, and 3.83–20.31%, respectively. Therefore, when designing and constructing concrete foundation piles, the influence of the thermal conductivity of frozen soil on concrete pile temperature should be considered first. The differences between the simulated and measured temperature along the concrete pile in the frozen soil varying with the respective thermal properties are: –2.99– 7.98◦C, –1.89–4.99◦C, –1.20–1.99◦C, and –1.76–1.27◦C. Polyurethane foam and other materials with small thermal conductivity can be added around the pile to achieve pile insulation.
Źródło:
Archives of Thermodynamics; 2023, 44, 2; 21--48
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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