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Wyszukujesz frazę "Chmura, D. K." wg kryterium: Autor


Wyświetlanie 1-5 z 5
Tytuł:
Self-tapping screw surface gas-phase cementation kinetics investigation, with EPDM washer
Badania kinetyki cementacji z fazy gazowej powierzchni wkrętów samogwintujących z podkładką z EPDM
Autorzy:
Khojibergenov, D. T.
Chmura, D. K.
Zobnin, N. N.
Islamkulov, K. M.
Powiązania:
https://bibliotekanauki.pl/articles/272614.pdf
Data publikacji:
2017
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Inżynierii Materiałów Polimerowych i Barwników
Tematy:
cementation
protective coating
corrosion resistance
self-tapping screw
cementacja
powłoka antykorozyjna
odporność na korozję
wkręty samogwintujące
Opis:
The kinetics of gas-phase cementation of goods – self-tapping metal screws for attachment of metal structures DIN 7982 / ISO 7050 with pointed ends from steels of SAE 1013-1018 to ASTM 510 grades was studied. The investigation was carried out by dynamic method with open volume, renewable gas phase, continuous delivery of natural gas to the flow system and its extraction from gaseous products of interaction. Chemical and phase composition of the surface coating was studied by means of low-vacuum raster electron microscope JSM 6490LV of JEOL company (Japan). A cementation of screws with washer from EPDM was examined. Experimental dependences of carbon concentration on the distance from the goods’ surface for various exposures in the cementation process were received. It was found that hardness of all elements of the hardened goods is notably higher than of the hardened goods. Thread, head and drill, i.e. off set elements of the goods are subjected to the maximum hardening. It was also substantiated that there is substantial decarbonization of the surface coating at a depth of 0.2–0.4 mm depending on the exposure time in the process of traditional hardening heat of the self-tapping screws. This explains lower values of the hardness of the thread, head and drill, the protruding elements of the goods. In comparison with the hardening, the cementation allows raise the hardness of the surface to 64−73 HRC (hardness in Rockwell scale C). Ways to raise corrosion resistance using the cementation were aimed. Among goods with protective coating (galvanized, oxidized) at the initial stage, the case-hardened goods have the lowest weight loss and during the whole time of the experiment the weight loss is substantially lower than the standard values.
Zbadano kinetykę cementacji z fazy gazowej wkrętów samogwintujących do mocowania struktur metalowych DIN 7982/ ISO 7050 z ostrymi końcami ze stali gatunków SAE 1013-1018 do ASTM 510. Niniejsze badanie zostało przeprowadzone za pomocą metody dynamicznej z otwartą objętościowo, odnawialną fazą gazową, ciągłym podawaniem naturalnego gazu do systemu przepływowego oraz jego ekstrakcją z gazowych produktów interakcji. Skład chemiczny i fazowy powłoki powierzchniowej był badany przy pomocy niskopróżniowego, rastrowego mikroskopu elektronowego JSM 6490LV firmy JEOL (Japonia). Zbadano także możliwość wykorzystania cementowanych śrub z nakrętkami, mającymi podkładki uszczelniające oparte na EPDM. Otrzymano doświadczalnie zależność stężenia węgla od odległości od powierzchni wyrobów dla różnych ekspozycji w procesie cementowania. Stwierdzono, że twardość wszystkich elementów wyrobów hartowanych jest istotnie wyższa niż wyrobów hartowanych. Gwint, główka i świderek gwintujący, tj. robocze elementy wyrobów poddawano maksymalnemu hartowaniu. Potwierdzono, że w procesie tradycyjnego hartowania cieplnego wkrętów samogwintujących zachodzi znaczna dekarbonizacja powłoki powierzchniowej na głębokość 0,2–0,4 mm, zależnie od czasu ekspozycji. To wyjaśnia niższe wartości twardości gwintu, główki i świderka gwintującego, zewnętrznych elementów tych wyrobów. W porównaniu z hartowaniem, cementowanie pozwala na podwyższenie twardości powierzchni do 64–73 HRC. Zwrócono uwagę na sposoby podniesienia odporności na korozję przy użyciu cementowania. Spośród wyrobów mających powłokę ochronną (galwanizowanych, oksydowanych) na wstępnym etapie, wyroby hartowane mają najmniejszą utratę masy, a podczas całego eksperymentu utrata masy jest istotnie niższa od standardowych wartości.
Źródło:
Elastomery; 2017, 21, 2; 92-99
1427-3519
Pojawia się w:
Elastomery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Do local enemies attack alien and native Impatiens alike?
Autorzy:
Najberek, K.
Solarz, W.
Chmura, D.
Powiązania:
https://bibliotekanauki.pl/articles/57062.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Botaniczne
Opis:
The enemy release hypothesis (ERH) attributes the invasive behavior of some alien species to decreased pressure from natural enemies, as they have been left behind in the hosts’ native range. The majority of research supports this idea, but some studies confirm it only partially or even contradict it. Here, we present the results of ERH tests of three Impatiens species studied in southern Poland in 2010–2011. Two of them are alien and invasive in Europe (Impatiens glandulifera, I. parviflora) and one is native (I. noli-tangere). We compared the three species in terms of the percentage of all leaves showing symptoms of disease and/or damage, and also the number of pests recorded on the monitored plants. In 1071 individual plant controls, we assessed 17 180 leaves, 7552 of which showed symptoms of disease/damage, and we recorded 5721 invertebrates, 5220 of them were pests. Rusts and spots were the predominant symptoms and Aphidoidea were the dominant group of pests. Comparisons of the two alien and one native Impatiens did not confirm the ERH in 90% of the performed tests. Most of the differences between the species were not significant, and most of the significant ones contradicted the ERH. The only results confirming the ERH were found in comparisons between I. parviflora and I. noli-tangere. The tests between two alien species showed that I. parviflora was under higher pest pressure, while I. glandulifera had more disease and damage symptoms, thus, plant–enemy relations differed between the two balsams. In summary, the presented results add evidence that the success of some alien species may depend on factors related to biotic and/or abiotic conditions in ways that are not explained by the enemy release hypothesis.
Źródło:
Acta Societatis Botanicorum Poloniae; 2017, 86, 4
0001-6977
2083-9480
Pojawia się w:
Acta Societatis Botanicorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Zmienność proweniencyjna olszy czarnej w Polsce
Provenance variability of black alder in Poland
Autorzy:
Rożkowski, R.
Mejnartowicz, L.
Guzicka, M.
Dorobek, K.
Chmura, D.J.
Powiązania:
https://bibliotekanauki.pl/articles/979576.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
drzewa lesne
olsza czarna
Alnus glutinosa
proweniencje
wysokosc drzew
piersnice drzew
piersnicowe pole przekroju
miazszosc drzew
zmiennosc proweniencyjna
alnus glutinosa
diameter
diversity
height
population
productivity
stem straightness
Opis:
European black alder (Alnus glutinosa (L.) Gaertn.) is a widespread tree species associated with wetlands and riparian ecosystems, thus it plays an important ecological role. Due to its fast growth and favorable wood properties it also has a potential to satisfy a growing demand for wood and fiber. However, its growth potential is not fully realized in Poland. In this study we investigated variation in growth traits, productivity, and stem straightness among 11 populations of European black alder originating from the lowland distribution of the species in Poland. The common−garden experiment located in 1968 in Kórnik (mid−western Poland) has been so far the only provenance experiment with this species in our country. We measured height and diameter of all trees at the site, assessed stem straightness in a 5−step scale (1−crooked; 5−straight), and calculated productivity at age of 50 years, which should be considered close to the rotation age. We found significant variation among populations in all investigated traits. The difference in productivity between the best and the worst provenance reached 75%. Using published and unpublished data from previous measurements at this site we also analyzed a trend in provenance ranking through time. The best and worst provenance could be identified at age 16 years, but many ranking shifts took place afterwards at the intermediate rank positions. We conclude that growth, productivity and stem quality of black alder could be improved through selection of favorable provenances within the species. Selection decisions can be made at the age below the half the rotation age, although decisions at 3/4 of rotation age would be more precise.
Źródło:
Sylwan; 2019, 163, 10; 830-838
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of drip irrigation of summer squash cultivated on the light soil
Autorzy:
Rolbiecki, R.
Rolbiecki, S.
Wichrowska, D.
Wojdyla, T.
Ptach, W.
Chmura, K.
Powiązania:
https://bibliotekanauki.pl/articles/61842.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Infrastruktura i Ekologia Terenów Wiejskich PAN
Tematy:
drip irrigation
summer squash
squash
plant cultivation
light soil
chemical composition
climate condition
Opis:
In the climatic conditions of Poland the temporary lack of rainfall during the vegetation season, influenced on the water deficits in the top soil level. This situation can effect on the height and quality of yields in particular years. There is estimated that in the – so called – Large Valleys Region the water deficiency ranged 200-300 mm. Production of cucurbit’s vegetables in open field is strictly connected with thermal-rainfall conditions during the vegetation season. The optimal soil moisture is the very important factor for high and good quality yield. So, the production of the cucurbit plants should be connected with the irrigation installations. The aim of the study was to determine the influence of drip irrigation in cultivation of summer squash ‘Danka’ under light soil conditions. The trials were conducted in the years 2004 – 2006 at the experimental field in Kruszyn Krajeński near Bydgoszcz – on a soil of rye weak complex. The plot area for harvest was 9,1 m2. The irrigation rates were done on the base of soil water potential according to tensiometer indications. The irrigation was started when the soil water tension was – 0,04 MPa. The fruits of the summer squash were harvested in the technological maturity in the second decade of September in each year of the study. The single weight and number of the fruits as well as marketable yield from the unit area were estimated. In the pulp the dry matter, vitamin C, sugars and carotenoids content were determineted. It was found that drip irrigation significantly increased the marketable yield of fruits. The higher yield increases were detected in the years with lower rainfalls. The significant influence of drip irrigation on the content of vitamin C and sugars was stated. The dry matter and carotenoids content were higher in the fruits from the irrigated plots, but the difference was insignificant.
Źródło:
Infrastruktura i Ekologia Terenów Wiejskich; 2014, IV/3
1732-5587
Pojawia się w:
Infrastruktura i Ekologia Terenów Wiejskich
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of invasive Fallopia taxa on resident plant species in two river valleys (southern Poland)
Autorzy:
Chmura, D.
Tokarska-Guzik, B.
Nowak, T.
Wozniak, G.
Bzdega, K.
Koszela, K.
Gancarek, M.
Powiązania:
https://bibliotekanauki.pl/articles/58507.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Botaniczne
Tematy:
invasive species
biological invasion
Fallopia
plant species
river valley
vegetation
phenology
Polska
Opis:
Riparian zones in two rivers in southern Poland were studied in terms of species composition and soil parameters in patches dominated by three knotweed taxa (Fallopia japonica, F. sachalinensis and the hybrid F. ×bohemica). The main purpose was to detect any differences in species diversity, environmental conditions and in the impact of the three Fallopia spp. on resident species. Fieldwork was conducted in spring and summer in 30 invaded plots (in total 90 subplots). It was demonstrated that vegetation dominated by particular knotweed taxa differed in response to soil pH and ammonium, nitrate, and magnesium content. Fallopia spp. (living plants and necromass) had a stronger negative impact on the cover and species diversity of the resident species in summer in comparison with spring. Vegetation patches differed significantly in species composition in relation to the knotweed taxa present. These differences may be the consequence of the differentiated biotopic requirements of Fallopia taxa and the coexisting plants, or to the different impact of the knotweed taxa on the resident species.
Źródło:
Acta Societatis Botanicorum Poloniae; 2015, 84, 1
0001-6977
2083-9480
Pojawia się w:
Acta Societatis Botanicorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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