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Wyszukujesz frazę "Strojny, T." wg kryterium: Autor


Wyświetlanie 1-2 z 2
Tytuł:
Czynniki wpływające na zmiany zwięzłości gleb leśnych podczas pozyskiwania surowca drzewnego
Factors affecting the changes in penetration resistance of forest soils during timber harvesting
Autorzy:
Kulak, D.
Stańczykiewicz, A.
Szewczyk, G.
Lubera, A.
Strojny, T.
Powiązania:
https://bibliotekanauki.pl/articles/989881.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
drzewostany sosnowe
trzebiez pozna
pozyskiwanie drewna
metody pozyskiwania drewna
oddzialywanie na glebe
gleby lesne
ugniatanie gleby
zwiezlosc gleb
timber harvesting
mechanized
motor−manual
soil penetration resistance
Opis:
The objective of the studies was to determine the penetration resistance (cohesion) of soil compacted at timber harvesting in Scots pine stands subjected to late thinning. The scope of the investigations was limited to two technologies – the mechanized one, using a harvester−forwarder machine set, as well as the motor−manual one, employing petrol chainsaws and a farm tractor for forwarding and dragging of felled trees. The analyses were performed in central Poland, in the Staszów Forest District, for two habitats – fresh mixed coniferous forest and fresh mixed deciduous forest. The measurements of soil cohesion were taken with the use of Eijkelkamp 06.15.SA Penetrologger penetrometer along the five measurement lines situated perpendicularly to the main skidding track. The soil penetration resistance was measured in eight spots for every measurement line: in the middle of the left and right wheel−rut, between the wheel−ruts, on the left and right roadside within a distance of 0.5 and 1 m from the wheel−rut edge, and 10 m from the right wheel−rut; the latter location was treated as the reference. The mechanized timber harvesting caused stronger compaction of soil, particularly in wheel−ruts, where the recorded values of soil cohesion exceeded 3 MPa (fig. 1). For the technology with farm tractor for skidding, the greatest soil compaction was also encountered in wheel−ruts, reaching up to 2.5 MPa. With regard to both logging technologies, the analysis of variability in penetration resistance of the top 10−cm soil horizon revealed a statistically significant increase in soil compaction in wheel−ruts when compared with other measuring points along and nearby the skid track (fig. 2). The employed technology of timber harvesting and the degree of soil cohesion in wheel−ruts were proved to be correlated. In respect of the mechanized variant, the mean value of soil penetration resistance in the top 10−cm layer counted up to 2 MPa and was significantly greater than the one in motor−manual technology, where it did not exceed 1.3 MPa. No significant differences in soil compaction in reference to the investigated forest habitats were revealed, though it was stronger in fresh mixed coniferous forest, with regard to both technological variants. The motor−manual technology caused the increase in soil penetration resistance by 2% on the roadside, nearly 20% in the middle of the skid track and over 70% in wheel−ruts. While the mechanized logging operations resulted in 30% increase in soil cohesion on the roadside, 55% between the wheel−ruts and over 250% inside the wheel−ruts (fig. 3).
Źródło:
Sylwan; 2015, 159, 04; 318-325
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Copper-Carbon Nanoforms Composites - Processing, Microstructure and Thermal Properties
Autorzy:
Pietrzak, K.
Gładki, A.
Frydman, K.
Wójcik-Grzybek, D.
Strojny-Nędza, A.
Wejrzanowski, T.
Powiązania:
https://bibliotekanauki.pl/articles/350995.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
metal matrix composite
sintering
copper
graphene
thermal diffusivity
Opis:
The main current of publication is focused around the issues and problems associated with the formation of composite materials with Cu matrix and reinforcing phases in the various carbon nanoforms. The core of the research has been focused on thermal conductivity of these composites types. This parameter globally reflects the state of the structure, quality of raw materials and the technology used during the formation of composite materials. Vanishingly low affinity of copper for carbon, multilayered forms of graphene, the existence of critical values of graphene volume in the composite are not conducive to the classic procedures of composites designing. As a result, the expected, significant increase in thermal conductivity of composites is not greater than for pure copper matrix. Present paper especially includes: (i) data of obtaining procedure of copper/graphene mixtures, (ii) data of sintering process, (iii) the results of structure investigations and of thermal properties. Structural analysis revealed the homogenous distribution of graphene in copper matrix, the thermal analysis indicate the existence of carbon phase critical concentration, where improvement of thermal diffusivity to pure copper can occur.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1307-1310
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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