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Tytuł:
Accounting for the random character of nucleation in the modelling of phase transformations in steels
Autorzy:
Poloczek, Łukasz
Kuziak, Roman
Foryś, Jakub
Szeliga, Danuta
Pietrzyk, Maciej
Powiązania:
https://bibliotekanauki.pl/articles/29519774.pdf
Data publikacji:
2023
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
stochastic model
grain size
phase transformations
dislocation density
cooling of rods
heterogeneity of the microstructure
Opis:
In our earlier work, a stochastic model of multi-stage deformation at elevated temperatures was developed. The model was applied to calculate histograms of dislocation density and grain size at the onset of phase transformation. The histograms were used as input data for the simulation of phase transitions using the traditional deterministic model. Following this approach, microstructural inhomogeneity was predicted for different cooling conditions. The results obtained, showing the effect of dislocation density and inhomogeneity of austenite grain size on the microstructural inhomogeneity of the final product, can be considered reliable as they are based on material models determined in previous publications and validated experimentally. The aim of the present work was to extend the model by taking into account the stochastic nature of nucleation during phase transitions. The analysis of existing stochastic models of nucleation was performed, and a model for ferritic transformation in steels was proposed. Simulations for constant cooling rates as well as for industrial cooling processes of steel rods were performed. In the latter case, uncertainties in defining the boundary conditions and segregation of elements were also considered. The reduction of the computing costs is an important advantage of the model, which is much faster when compared to full field models with explicit microstructure representation.
Źródło:
Computer Methods in Materials Science; 2023, 23, 2; 17-28
2720-4081
2720-3948
Pojawia się w:
Computer Methods in Materials Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An analytical model to predict water retention curves for granular materials using the grain-size distribution curve
Autorzy:
Bouacida, Linda
Feia, Sadok
Denine, Sid Ali
Della, Noureddine
Powiązania:
https://bibliotekanauki.pl/articles/2172891.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
sand
mean grain size
mean pore size
density index
model
pore size distribution
water retention curve
Opis:
The present work aims to propose a new analytical model intended to predict the water retention curves for granular materials based on data from tensiometric tests. Different analytical models have been used for the evaluation of soil water retention curves so far. It should be noted that the proposed model considers only one criterion in the selection of soils. This criterion is the physical property of particle distribution curve that can be used to determine the values of D50 and CU. In this study, the pore-access size distribution is investigated considering the effect of the coefficient of uniformity of sandy soils that were prepared with different density indexes (0.5, 0.7, and 0.9). Moreover, the proposed model equation is based on the physical properties of soil. This equation made it possible to describe the water retention curve and to estimate the pore-access size distribution without performing any experimental tests. The findings allowed asserting that the uniformity of the particle size curves corresponds to a good uniformity of the pore-access size distribution. In addition, it was revealed that the suction increased as the density index went up, which matches well with the experimental data. Moreover, it may clearly be noted that the distinctive retention properties of unsaturated soils can be observed on the above-mentioned curves. Further, it was found that the ratio of the grain size over the pore-access size increased as the uniformity coefficient augmented.
Źródło:
Studia Geotechnica et Mechanica; 2022, 44, 4; 354--369
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of the compressive strength parallel to the grain of resinous yellow pine heartwood
Autorzy:
Mańkowski, Piotr
Laskowska, Agnieszka
Powiązania:
https://bibliotekanauki.pl/articles/2200211.pdf
Data publikacji:
2020
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
Tematy:
compressive strength parallel to the grain
density
deflection
load
resin
resinosis
yellow pine
Opis:
Determination of the compressive strength parallel to the grain of resinous yellow pine heartwood. The compressive strength parallel to the grain of resinous yellow pine heartwood was determined as a part of this study. The interdependencies between the load and deflection of yellow pine under compression test were established. The average density of resinous yellow pine wood in an air-dry condition was 855 ± 10 kg/m3 and it was 30% greater than the density of non-resinous yellow pine wood. Despite a considerable increase in density, which was due to the saturation of wood with resin, a 4% decrease in the compressive strength parallel to the grain of yellow pine heartwood was recorded and the differences were statistically significant. The load-deflection curves of yellow pine wood showed a similar direction of changes for resinous and non-resinous heartwood. Nevertheless, significant differences in the deflection values between resinous and non-resinous yellow pine heartwood were demonstrated, depending on the load.
Badanie wytrzymałości na ściskanie wzdłuż włókien przeżywiczonego drewna twardzieli sosny żółtej. W ramach badań oznaczono wytrzymałość na ściskanie wzdłuż włókien przeżywiczonego drewna sosny żółtej ze strefy twardzieli. Celem porównania zbadano wytrzymałość na ściskanie wzdłuż włókien nieprzeżywiczonego drewna twardzieli sosny żółtej. Określono zależności pomiędzy obciążeniem i odkształceniem sosny żółtej w teście wytrzymałości na ściskanie. Gęstość średnia przeżywiczonego drewna sosny żółtej w stanie powietrzno-suchym wynosiła 855 ± 10 kg/m3 i była o 30% większa od gęstości nieprzeżywiczonego drewna sosny żółtej. Pomimo znacznego wzrostu gęstości wynikającego z przesycenia drewna żywicą odnotowano spadek wytrzymałości na ściskanie wzdłuż włókien o 4% i różnice te były statystycznie istotne. Zależności obciążenie - odkształcenie prezentowały podobny kierunek zmian dla twardzieli przeżywiczonej i nieprzeżywiczonej. Wykazano jednak istotne różnice w wartościach odkształceń w zależności od obciążenia pomiędzy nieprzeżywiczoną i przeżywiczoną twardzielą sosny żółtej.
Źródło:
Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology; 2020, 109; 81--85
1898-5912
Pojawia się w:
Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The reaction of two types of maize cultivars (zea mays l.) to different sowing density
Reakcja dwóch typów odmian kukurydzy (zea mays l.) na zróżnicowaną gęstość siewu
Autorzy:
Szulc, Piotr
Ambroży-Deręgowska, Katarzyna
Mejza, Iwona
Zawadzka, Agnieszka
Zielewicz, Waldemar
Byczkiewicz, Szymon
Powiązania:
https://bibliotekanauki.pl/articles/1333427.pdf
Data publikacji:
2020-12-31
Wydawca:
Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Maszyn Rolniczych
Tematy:
maize cultivars
sowing density
yield components
grain yield
odmiany kukurydzy
gęstość siewu
komponenty plonowania
plon ziarna
Opis:
The aim of the study was to determine the effect of sowing density on grain yield of two types of maize cultivars. The field experiment was carried out in 2012-2014 at the Department of Agronomy at the Poznań University of Life Sciences. The first order factor was: the cultivars SY Cooky and Drim “stay-green”, while the second order factor was: sowing den-sity of 6, 7, 8, 9 and 10 plants per 1 m-2. The thermal and humidity conditions in the growing seasons of maize significantly influenced grain yield, ear grain number, grain moisture and the number of production ears per area unit. The “stay-green” cultivar was characterized by significantly higher grain yield compared to the traditional cultivar. The increase in sowing density decreased 1000 seed weight and ear grain number, while it increased the number of production ears per area unit and maize grain moisture during harvest. No significant interaction of the studied types of maize cultivars with sowing density in shaping grain yield components, moisture and grain yield was demonstrated.
Celem pracy było określenie wpływu gęstości siewu na wielkość plonu ziarna dwóch typów odmian kukurydzy. Doświadczenie polowe prowadzono w latach 2012-2014 w Katedrze Agronomii Uniwersytetu Przyrodniczego w Poznaniu. Czyn-nikiem I rzędu była odmiana: SY Cooky i Drim „stay-green”, natomiast czynnikiem II rzędu gęstość siewu: 6, 7, 8, 9, 10 ro-ślin na 1 m-2.Warunki termiczne i wilgotnościowe w sezonach wegetacyjnych kukurydzy w istotny sposób kształtowały plon ziarna, liczbę ziaren w kolbie, wilgotność ziarna oraz liczbę kolb produkcyjnych na jednostce powierzchni. Mieszaniec w typie „stay-green” charakteryzował się istotnie wyższym plonem ziarna w porównaniu do odmiany tradycyjnej. Wzrost gęstości siewu spowodował spadek masy 1000 nasion i liczby ziaren w kolbie, natomiast zwiększyła się liczba kolb produkcyjnych na jednostce powierzchni oraz wilgotność ziarna kukurydzy podczas zbioru. Nie wykazano istotnego współdziałania ba-danych typów odmian kukurydzy z gęstością siewu w kształtowaniu komponentów plonu ziarna, wilgotności i plonu ziarna.
Źródło:
Journal of Research and Applications in Agricultural Engineering; 2020, 65, 2; 12-17
1642-686X
2719-423X
Pojawia się w:
Journal of Research and Applications in Agricultural Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The susceptibility of Scots pine heartwood from various Polish forestry regions to the brown rot fungus Coniophora puteana (Schumach.) P. Karst
Autorzy:
Mańkowski, Piotr
Krzosek, Sławomir
Andres, Bogusław
Powiązania:
https://bibliotekanauki.pl/articles/2010880.pdf
Data publikacji:
2020
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Technologii Drewna
Tematy:
Pinus sylvestris L.
Coniophora puteana
wood density
compression strength
compressive strength parallel to grain
Opis:
This paper presents the results of tests of compression strength parallel to the grain, conducted on pine wood (Pinus sylvestris L.) samples from various Polish forestry regions, exposed to the Coniophora puteana fungus. According to the test results, the resistance of wood to the fungus varies only slightly depending on its place of origin. Exposure to the tested fungus caused a reduction of density and compression strength parallel to the grain. No correlation was found between this reduction and the place of origin of pine wood samples.
Źródło:
Drewno. Prace Naukowe. Doniesienia. Komunikaty; 2020, 63, 206; 63-76
1644-3985
Pojawia się w:
Drewno. Prace Naukowe. Doniesienia. Komunikaty
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Średni ciężar atomowy i gęstość ziaren chondrytu Jezersko (H4)
Mean atomic weight and grain density of Jezersko H4 chondrite
Autorzy:
Szurgot, Marian
Powiązania:
https://bibliotekanauki.pl/articles/1033134.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Meteorytowe
Tematy:
H chondrites
Jezersko chondrite
grain density
iron to silicon ratio
mean atomic number
mean atomic weight
ordinary chondrites
weathering effects
Opis:
Mean atomic weight Amean of Jezersko (H4 S2(3) W2, find in 1992 in Slovenia) ordinary chondrite has been calculated using literature data on chemical composition of the meteorite (Miler et al. 2014) and using relationship between mean atomic weight and Fe/Si atomic ratio (Szurgot 2015c, d, e). It was shown that Jezersko’s Amean = 24.68, for composition without water. This value is close to the mean atomic weight of H chondrite finds (Amean = 24.80), and is somewhat smaller than Amean values for H4 chondrite falls (Amean = 25.09), and for H chondrite falls (Amean = 25.05) (Szurgot 2015e). Jezersko’s Fe/Si atomic ratio (0.742) leads to Amean = 24.66±0.24, which is close to the value determined by bulk composition. Jezersko’s Fe/Si atomic ratio is close to the value for H’s mean Fe/Si ratio: 0.762 for finds, and 0.807 for falls (Szurgot 2016a). This confirms that Jezersko belongs to H chondrites, as previously classified (Miler et al. 2014). Mean atomic number Zmean, and Amean/Zmean ratio of the meteorite have been also calculated. Jezersko’s Zmean = 12.16, and Amean/Zmean ratio is: 2.029 for composition without water. Jezersko’s silicates shown the values: Amean = 21.77, Zmean = 10.78, Amean/Z mean = 2.019, Fe/Si = 0.272, Amean(Fe/Si) = 21.84±0.06, and Jezersko’s Fe,Ni metal values: Amean = 56.12, Zmean = 26.19, and Amean/Z mean = 2.143. Two dependences: i) grain density dgr on Amean (Szurgot 2015a), and ii) grain density dgrain on Fe/Si atomic ratio (Szurgot 2017g), were used to predict grain density of Jezersko chondrite. It was established that dgr(Amean) leads to the values: 3.65±0.07 g/cm3 for Jezersko chondrite, 3.27±0.07 g/cm3 for silicates, and 7.83±0.07 g/cm3 for Fe,Ni metal of Jezersko meteorite. Dependence dgr(Fe/Si) predicts somewhat higher value grain density for Jezersko chondrite: 3.68±0.07 g/cm3, and 3.32±0.07 g/cm3 for silicates. All the predictions lead to the mean value of grain density for its weathering W2 degree: 3.67±0.03 g/cm3 for the whole rock of meteorite, and 3.29±0.03 g/cm3 for the silicates. It was established that due to terrestrial weathering, resulting in W2 weathering stage, Amean value of Jezersko chondrite is about 0.45 lower, Fe/Si atomic ratio is about 0.075 lower, and dgrain is about 0.06 g/cm3 lower than values for unweathered (W0) meteorite. Predicted porosity for Jezersko chondrite is: 10,1±0,7% for W2, and 11,5±0,5% for W0.
Źródło:
Acta Societatis Metheoriticae Polonorum; 2019, 10; 140-159
2080-5497
Pojawia się w:
Acta Societatis Metheoriticae Polonorum
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Średni ciężar atomowy chondrytu Vicência (LL3.2)
Mean atomic weight of Vicência LL3.2 chondrite
Autorzy:
Szurgot, Marian
Powiązania:
https://bibliotekanauki.pl/articles/1033113.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Meteorytowe
Tematy:
LL3 chondrites
Mössbauer spectroscopy
Vicência chondrite
grain density
iron to silicon ratio
mean atomic number
mean atomic weight
ordinary chondrites
troilite content
Opis:
Mean atomic weight Amean of Vicência (LL3.2 S1W0, fall 2013) ordinary chondrite has been calculated using literature data (Keil et al. 2015) on chemical composition of the meteorite and using relationships: between mean atomic weight and Fe/Si atomic ratio, between Amean and grain density, and between Amean and magnetic susceptibility. It was shown that Vicência’s Amean = 22.91 for composition without water. This value is close to the mean atomic weight of LL chondrite falls, is close to Amean value of LL3 chondrite falls, and is close to Amean value of Semarkona LL3.0 chondrite. Vicência’s Fe/Si atomic ratio (0.492±0.050) leads to Amean = 23.06–23.26, which is close to the value determined by bulk composition. Vicência’s Fe/Si atomic ratio is close to the value for Semarkona’s (Fe/Si = 0.511), and is close to LL’s mean Fe/Si ratio (0.520). This confirms that Vicência belongs to LL chondrites, as previously classified. Using dependence between mean atomic weight and grain density leads to Amean = 21.89±0.54 (dgr = 3.28 g/cm3, Keil et al. 2015), and using dependence between Amean and magnetic susceptibility gives Amean = 23.01±0.24 (logc = 4.30, Keil et al. 2015). Arithmetic mean of Amean (dgr), Amean (logc), and Amean(Fe/Si), gives 22.72±0.73, the value close to Amean(bulk composition) determined using compositional data. Mean atomic number Zmean, and Amean/Zmean ratio of the meteorite have been also calculated. Vicência’s Zmean = 11.37, and Amean/Zmean ratio is: 2.015 for composition without water. Vicência’s silicates shown the values: Amean = 21,67, Zmean = 10.76, Amean/Z mean = 2.014, Fe/Si = 0.318, Amean(Fe/Si) = 22.07–22.18, and Fe, Ni metal values: Amean = 56.63, Zmean = 26.53, and Amean/Z mean = 2.135. Two dependences: i) grain density dgr on Amean, and ii) grain density dgr on Fe/Si atomic ratio, were used to determine/verify grain density of Vicência chondrite. It was established that dgr(Amean) leads to the values: 3,42 g/cm3 for Vicência chondrite, 3,25 g/cm3 for silicates, and 7,90 g/cm3 for Fe, Ni metal of Vicência meteorite. Dependence dgr(Fe/Si) predicts density for Vicência chondrite: 3,47–3,49 g/cm3, and for silicates: 3,32–3,35 g/cm3.
Źródło:
Acta Societatis Metheoriticae Polonorum; 2018, 9; 126-144
2080-5497
Pojawia się w:
Acta Societatis Metheoriticae Polonorum
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of Postflotation Tailings in Hydroengineering Structures
Autorzy:
Stefaniak, K.
Wróżyńska, M.
Kroll, M.
Powiązania:
https://bibliotekanauki.pl/articles/952360.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
postflotation tailings
earthen dams
density measures
grain size parameters
Opis:
Economic development stimulated by the increased demand for production of consumer goods and the growing human population result in increasing the amounts of various wastes, including tailings. Mining industry in Poland, comprising also mining of non-ferrous metal ores, is a strategic branch of the national economy and, at the same time, a leading waste producer. Tailings management is a significant problem both in Poland and worldwide. Frequently, considerable amounts of wastes are accumulated in mine spoil tips, in areas not always suitable for their deposition, thus leading to the degradation of the surrounding environment. At the huge volume of produced wastes their rational and economically viable management is becoming crucial. On the other hand, depletion of natural aggregate deposits is an important incentive to search for substitutes, which would be suitable for the development of road infrastructure or which could be used in earth structure engineering to construct hydroengineering objects. Since no profitable recovery technologies are available at present, tailings generated by copper mining are deposited in tailings storage facilities. The largest and at the same time the only currently operating facility in Poland is the Żelazny Most Mining Tailings Storage Facility, belonging to KGHM Polska Miedź S.A. The paper presents criteria for material quality and density imposed on the material embedded in the static core of the tailings pond dam. For this purpose studies were conducted to confirm applicability of sorted tailings as a material for the construction of earth structures.
Źródło:
Journal of Ecological Engineering; 2017, 18, 1; 113-118
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Średni ciężar atomowy chondrytu Ensisheim (LL6)
Mean atomic weight of Ensisheim LL6 chondrite
Autorzy:
Szurgot, Marian
Powiązania:
https://bibliotekanauki.pl/articles/1033088.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Meteorytowe
Tematy:
Ensisheim chondrite
LL6 chondrite
grain density
iron to silicon ratio
mean atomic number
mean atomic weight
ordinary chondrite
Opis:
Mean atomic weight Amean of Ensisheim (LL6, fall 1492) ordinary chondrite has been determined using literature data on chemical composition of the meteorite and using relationships: between mean atomic weight and Fe/Si atomic ratio, between Amean and grain density, and between Amean and magnetic susceptibility (Szurgot 2015a–f, 2016a, b, d, e). It was shown that Ensisheim’s Amean = 23.32, and 23.06 for composition without water, and with H2O, respectively. These values are close to the mean atomic weight of LL chondrite falls (Amean = 23.36, and 23.03), and are close to Amean values of LL6 chondrite falls (Amean = 23.30, and 23.06, Szurgot 2016b). Ensisheim’s Fe/Si atomic ratio (0.509) leads to Amean = 23.16±0.12 which is close to the values determined by bulk composition. This means that Ensisheim belongs to LL6 chondrites, as previously classified (Jarosewich i Dodd 1985). Using dependence between mean atomic weight and grain density (Szurgot 2015a–c, 2016d) leads to Amean = 23.70±0.54 (dgr = 3.52±0.04 g/cm3, Macke 2010), and using dependence between Amean and magnetic susceptibility (Szurgot 2016a, d) gives Ameanc = 22.78±0.24 (logc = 4.15±0.09, Macke 2010). Arithmetic mean Amean (dgr) and Amean (logc) gives 23.24±0.65, and arithmetic mean of Amean (dgr), Amean (logc), and Amean(Fe/Si), gives 23.21±0.46 values close each other, and close to Amean(bulk composition) determined using compositional data. Mean atomic number Zmean, and Amean/Zmean ratio of the meteorite have been also determined. Ensisheim’s Zmean = 11.51 for composition without H2O, and 11.40 for composition with H2O. Amean/Zmean ratios are: 2.026 and 2.023, for composition without water, and with H2O, respectively. Ensisheim’s silicates shown values: Amean = 22.19, Zmean = 10.97, Amean/Z mean = 2.022, Fe/Si = 0.355, Amean(Fe/Si) = 22.28, and Fe, Ni metal values: Amean = 57.26, Zmean = 26.96, and Amean/Z mean = 2.124.
Źródło:
Acta Societatis Metheoriticae Polonorum; 2017, 8; 110-122
2080-5497
Pojawia się w:
Acta Societatis Metheoriticae Polonorum
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Średni ciężar atomowy chondrytów LL5: Siena, Hautes Fagnes i NWA 7915
Mean atomic weight of LL5 chondrites: Siena, Hautes Fagnes and NWA 7915
Autorzy:
Szurgot, Marian
Powiązania:
https://bibliotekanauki.pl/articles/1033066.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Meteorytowe
Tematy:
Hautes Fagnes
NWA 7915 chondrite
Siena chondrite
chondrites
elemental composition
grain density
mean atomic number
mean atomic weight
Opis:
Mean atomic weights Amean of Siena (LL5, fall 1794), Hautes Fagnes (LL5, S1, W1, find 1965) and NWA 7915 (LL5, S2, W3, find 2010) ordinary chondrites have been determined using literature data on chemical composition of the meteorites and using relationship between mean atomic weight and Fe/Si atomic ratio (Szurgot 2015). It was shown that NWA 7915 Amean = 22.80 is close to mean atomic weight of LL chondrites (Amean = 23.00), and is close to mean atomic weight of LL chondrite falls (Amean = 22.90, Szurgot 2015). NWA 7915’s Fe/Si atomic ratio (0.529) leads to Amean = 23.28 which is close to the value determined by bulk composition. This means that NWA 7915 belongs to LL5 chondrites, as previously classified (Brawata et al. 2014). Mean atomic weight Amean of Hautes Fagnes determined by bulk composition is between 23.11 and 23.35. Lower Amean value is close to Amean of LL chondrites, but higher value is the same as Amean of intermediate L/LL chondrites (23.34 for L/LL, Szurgot 2016). Hautes Fagnes Fe/Si atomic ratio and Amean(Fe/Si) are identical with those for NWA 7915 (Fe/Si = 0.529, Amean = 23.28). Amean data indicate that Hautes Fagnes can belong to LL5 chondrites, as previously classified (Vandeginste et al. 2012) or can be one of L/LL chondrites. Mean atomic weight of Siena meteorite is much higher than expected for LL chondrite. Siena’s bulk composition gives Amean = 24.47, and Amean(Fe/Si) dependence gives Amean = 24.45 (Fe/Si = 0.7345). Using dependence between mean atomic weight and grain density (Szurgot 2015) leads to Amean = 23.24 (dgr = 3.46 g/cm3, Macke 2010), and using dependence between Amean and magnetic susceptibility (Szurgot 2016) gives Amean = 23.53±0.13 (logc = 4.65±0.09, Macke 2010). Bulk composition and Fe/Si ratio indicate that Siena has the same Amean as intermediate H/L chondrites, for which Amean = 24.3 (Szurgot 2016). Grain density indicates rather L/LL intermediate group for Siena, and magnetic susceptibility indicates intermediate L/LL or L chondrites (23.34 for L/LL, and 23.67 for L, Szurgot 2016). Mean atomic number Zmean, and Amean/Zmean ratio of the three meteorites have been also determined. Siena’s Zmean = 12.104, Hautes Fagnes Zmean = 11.445–11.562, and NWA 7915’s Zmean = 11.293. Amean/Zmean ratios are: 2.022 for Siena, 2.019–2.020 for Hautes Fagnes, and 2.019 for NWA 7915.
Źródło:
Acta Societatis Metheoriticae Polonorum; 2016, 7; 133-143
2080-5497
Pojawia się w:
Acta Societatis Metheoriticae Polonorum
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impact of weed control method and sowing density on yielding of selected winter spelt (Triticum spelta L.) cultivars
Wpływ metody ograniczania zachwaszczenia i ilości wysiewu na plonowanie wybranych odmian pszenicy orkisz (Triticum spelta L.)
Autorzy:
Puzynski, S.
Stankowski, S.
Puzynska, K.
Iwanski, R.
Wianecki, M.
Biel, W.
Powiązania:
https://bibliotekanauki.pl/articles/82920.pdf
Data publikacji:
2015
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
weed control
control method
sowing density
yielding
winter spelt
spelt
Triticum spelta
plant cultivar
grain yield
Źródło:
Folia Pomeranae Universitatis Technologiae Stetinensis. Agricultura, Alimentaria, Piscaria et Zootechnica; 2015, 36
2081-1284
Pojawia się w:
Folia Pomeranae Universitatis Technologiae Stetinensis. Agricultura, Alimentaria, Piscaria et Zootechnica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Średni ciężar atomowy chondrytu Sołtmany, chondrytów L6 i minerałów pozaziemskich
Mean atomic weight of Sołtmany chondrite, L6 chondrites and extraterrestrial minerals
Autorzy:
Szurgot, Marian
Powiązania:
https://bibliotekanauki.pl/articles/1033038.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Meteorytowe
Tematy:
Girgenti chondrite
Holbrook chondrite
Jesenice chondrite
Leedey chondrite
Modoc chondrite
Sołtmany chondrite
chondrites
elemental composition
grain density
mean atomic weight
Opis:
Mean atomic weight Amean of Sołtmany (L6, S2, W0) ordinary chondrite, various L6 chondrites such as: Jesenice, Girgenti, Leedey, Bruderheim, Holbrook and Modoc, as well as LL, L and H chondrites has been determined using literature data on chemical composition of the meteorites. Relationship between mean atomic weight and Fe/Si atomic ratio for ordinary chondrites has been established. It was shown that Sołtmany’s Amean = 23.97 is close to mean atomic weight of L chondrites Amean = 23.70, and is close to mean atomic weight of L6 chondrites Amean = 24.06±0.16. It has been established that Sołtmany’s Fe/Si atomic ratio (Fe/Si = 0.588) is close to Fe/Si ratio for L6 chondrites (Fe/Si = 0.598). This means that Sołtmany belongs to L6 chondrites, as previously classified. Using discovered by the author (Szurgot, 2015) dependence between mean atomic weight and uncompressed density of planetary matter it was established that grain density of Sołtmany meteorite should be equal to 3.56±0.12 g/cm3, which is about 4% lower than previously estimated by porosity data. Mean atomic weight of extraterrestrial minerals present in ordinary chondrites and in Sołtmany meteorite have been also determined.
Źródło:
Acta Societatis Metheoriticae Polonorum; 2015, 6; 107-128
2080-5497
Pojawia się w:
Acta Societatis Metheoriticae Polonorum
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Weryfikacja modeli heterogenicznego zarodkowania ziaren pierwotnych w stopie Al-5Cu
Verification of Models of Heterogeneous Nucleation of Primary Grains in Al-5Cu Alloy
Autorzy:
Górny, M.
Sikora, G.
Powiązania:
https://bibliotekanauki.pl/articles/381989.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
zarodkowanie heterogeniczne
modele zarodkowania
gęstość ziaren pierwotnych
przechłodzenie ciekłego stopu
rozkład statystyczny
heterogeneous nucleation
nucleation models
density of the original grain
supercooling a molten
statistical distribution
Opis:
Gęstość ziaren pierwotnych Nv po krystalizacji zależy od maksymalnego przechłodzenia ΔT ciekłego stopu. Zależność ta może być oparta o różne rozkłady statystyczne: Gaussa, Weibulla, lognormalny oraz zależy od charakterystyki heterogenicznych miejsc zarodkowania oraz ich aktywnej liczby obecnej w ciekłym stopie odlewniczym. Celem niniejszej pracy jest skonfrontowanie wyników doświadczalnych z istniejącymi już modelami Oldfielda, Frasia, lognormalnego oraz wyznaczenie wartości parametrów zarodkowania tych modeli, które są charakterystyczne dla badanego stopu Al-5Cu. Zweryfikowano modele zarodkowania ziaren fazy pierwotnej α(Al) w stopie Al-5Cu w stanie wyjściowym oraz modyfikowanym. Z przeprowadzonej analizy wynika, że model Oldfielda wykazuje dobrą zgodność z wynikami doświadczalnymi, ale tylko dla stanu wyjściowego, podczas gdy modele lognormalny oraz Frasia (oparty na rozkładzie statystycznym Weibulla) są równoważne pod względem dobrego odwzorowania wyników doświadczalnych dla zarodkowania ziaren fazy pierwotnej α(Al) w stopie Al-5Cu zarówno dla stanu wyjściowego jak i modyfikowanego.
The grain density Nv after solidification is a function of maximum undercooling of a liquid alloy ΔT. This relationship may be based on the different statistical distributions: Gaussian, Weibull, Lognormal and depends on the characteristics of heterogeneous nucleation sites present in the liquid alloy. The purpose of this work was a compare the experimental data with the models: Oldfield, Fras and Lognormal and determination the nucleation parameters of these models, which are characteristic for the investigated alloy Al-5Cu. The models of nucleation of primary grains α(Al) in the alloy Al-5Cu was verified for two physicochemical state of liquid metal: base and refined. The analysis shows that the model Oldfield has a good compatibility with experimental results, but only for the base alloy. The lognormal and Fras (based on Weibull's distribution) models are equivalent as regards a good representation of the experimental results of the nucleation of primary grains α(Al) in the alloy Al-5Cu for both physicochemical state.
Źródło:
Archives of Foundry Engineering; 2014, 14, 4 spec.; 31-36
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Związki między wybranymi cechami drzewa a niektórymi właściwościami drewna młodocianego sosny zwyczajnej (Pinus sylvestris L.)
Relationships between selected tree characteristics and the properties of juvenile wood in Scots pine (Pinus sylvestris L.)
Autorzy:
Tomczak, A.
Powiązania:
https://bibliotekanauki.pl/articles/1312952.pdf
Data publikacji:
2014
Wydawca:
Instytut Badawczy Leśnictwa
Tematy:
lesnictwo
drzewa lesne
sosna zwyczajna
Pinus sylvestris
cechy morfologiczne
wysokosc drzew
piersnice drzew
wysokosc osadzenia pierwszej zywej galezi
srednica korony
dlugosc korony
drewno sosnowe
drewno mlodociane
gestosc drewna
gestosc umowna
wytrzymalosc na sciskanie wzdluz wlokien
wytrzymalosc na zginanie statyczne
modul elastycznosci przy zginaniu
korelacja cech
basic density
strength perpendicular to grain
bending strength
modulus of elasticity
breast height
diameter
tree height
crown length
crown diameter
Opis:
The aim of this study was to determine relationships between selected properties of juvenile wood and characteristics of the stem and crown of Scots pine. Analyses were conducted in northern Poland in eight mature pine monocultures. Nine trees were selected in each experimental site and their stems were divided into five sections. The centers of the sections were established at a height of 1.3 m from the tree base and at points corresponding to 20, 40, 60 and 80% tree height. Samples were taken from these locations, and these samples were prepared for analyses of basic density, compressive strength along the grain and static bending, as well as the modulus of elasticity during bending. The mean height of the investigated group of trees was 26.0 m with an average diameter breast high of 33.6 cm. The mean crown depth was 7.8 m and crown diameter was 3.6 m, and the mean basic density (Qu) of juvenile pine wood was 416 kg/m3. The average compressive strength along the grain (CS) was determined to be 22.3 MPa, while static bending strength (BS) was 45.8 MPa. The recorded modulus of elasticity (MOE) was 4726 MPa. Both in general terms and when dividing stems into sections, the wood properties correlated with tree characteristics to various degrees. All indexes were negative indicating that trees of greater dimensions produce juvenile wood of inferior quality. Properties of juvenile wood formed during various periods of tree life were mostly related to diameter breast high and crown depth. They were also correlated with tree height, but only to a limited extent. In contrast, properties of wood from the middle stem sections were significantly correlated with crown diameter.
Źródło:
Leśne Prace Badawcze; 2014, 75, 3; 237-244
1732-9442
2082-8926
Pojawia się w:
Leśne Prace Badawcze
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wzmocnienie desorpcyjne jako podstawa oceny jakości drewna dębu szypułkowego (Quercus robur L.) i dębu burgundzkiego (Quercus cerris L.)
Desorption strengthening as a basis for the assessment of wood quality of pedunculate oak (Quercus robur L.) and Turkey oak (Quercus cerris L.)
Autorzy:
Szymański, M.
Szykowny, T.
Pazdrowski, W.
Nawrot, M.
Powiązania:
https://bibliotekanauki.pl/articles/994476.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
drzewa lesne
dab szypulkowy
Quercus robur
dab burgundzki
Quercus cerris
drewno debowe
jakosc
gestosc drewna
gestosc umowna
wytrzymalosc na sciskanie wzdluz wlokien
wzmocnienie desorpcyjne
conventional wood density
compressive strength along the grain
basic strength
desorption strengthening
wood quality
Opis:
The analysis was conducted on the wood of two 100−year−old oak species that grew in the riparian forest conditions. The aim of the study was to determine the effect of tree species on conventional wood density, compressive strength along the grain with a moisture content of 12% and above 30% and desorption strengthening. It was found that wood of both oak species differed in density, compressive strength along the grain and desorption strengthening. These differences should be taken into account in the processing and use of timber harvested in the prescribed cuts.
Źródło:
Sylwan; 2013, 157, 11; 811-816
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
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