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    Wyświetlanie 1-12 z 12
    Tytuł:
    A Model for Fatigue Crack Growth in the Paris Regime under the Variability of Cyclic Hardening and Elastic Properties
    Autorzy:
    Kebir, T.
    Benguediab, M.
    Imad, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/97819.pdf
    Data publikacji:
    2017
    Wydawca:
    Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
    Tematy:
    cyclic plastic strain
    elastic properties
    cyclic hardening parameters
    Young's modulus
    variability
    crack tip
    fatigue crack growth
    constants of the Paris law
    Al-alloys
    Opis:
    Over the last 60 years, several models have been developed governing different zones of fatigue crack growth from the threshold zone to final failure. The best known model is the Paris law and a number of its based on mechanical, metallurgical and loading parameters governing the propagation of cracks. This paper presents an analytical model developed to predict the fatigue crack propagation rate in the Paris regime, for different material properties, yield strength (σy), Young’s modulus (E) and cyclic hardening parameters (K’, n’) and their influence by variability. The cyclic plastic deformation at a crack tip or any other cyclic hardening rule may be used to reach this objective, for to investigate this influence, these properties of the model are calibrated using available experimental data in the literature. This FCGR model was validated on Al-alloys specimens under constant amplitude load and shows good agreement with the experimental results.
    Źródło:
    Fatigue of Aircraft Structures; 2017, 9; 117-135
    2081-7738
    2300-7591
    Pojawia się w:
    Fatigue of Aircraft Structures
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effect of L-glycine on the Growth and Selected Nutritional Elements of Butterhead Lettuce
    Autorzy:
    Rosa, Robert
    Franczuk, Jolanta
    Zaniewicz-Bajkowska, Anna
    Remiszewski, Karol
    Dydiv, Ihor
    Powiązania:
    https://bibliotekanauki.pl/articles/2173283.pdf
    Data publikacji:
    2022
    Wydawca:
    Polskie Towarzystwo Inżynierii Ekologicznej
    Tematy:
    amino acid
    L-glycine
    Lactuca sativa L. var. capitata
    growth parameters
    nutritional value
    Opis:
    In agricultural practice, there is a need to change the forms of fertilizers to be friendlier to the natural environment and human health. To this end, research has been carried out on the partial replacement of fertilisers containing nitrates or ammonium compounds with amino acid nitrogen. The present studies assessed the effect of L-glycine on growth parameters and on the content of selected nutrients in the butterhead lettuce grown in an unheated greenhouse in the spring. The treatment consisted of foliar L-glycine application at the following concentrations: 0, 20, 40, 60, 80, 100, 120, 140, 160, 180, 200, 220 and 240 mg∙L-1, with a solution dose of 50 ml∙m-2. Foliar application of L-glycine improved the butterhead lettuce growth parameters. The most favourable values of the head weight, root system weight and the number and length of leaves were recorded for the plants fed with doses ranging from 80 to 120 mg∙L-1. The weight of the head and the root system was most favourable after foliar feeding with 120 mg∙L-1 of L-glycine. Additionally, a high value of the SPAD leaf greenness index was noted as a response to the same dose, indicating a high level of leaf nitrogen nutrition. However, foliar feeding with L-glycine had no statistically significant effect on the nutritional value of lettuce, i.e. the content of dry matter, protein, sugars and ascorbic acid.
    Źródło:
    Journal of Ecological Engineering; 2022, 23, 7; 20--28
    2299-8993
    Pojawia się w:
    Journal of Ecological Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effects of biodynamic preparations on the growth and yield parameters of potatoes with coloured flesh
    Wpływ preparatów biodynamicznych na wzrost i plonowanie bulw ziemniaków o kolorowym miąższu
    Autorzy:
    Jarienė, Elvyra
    Danilčenko, Honorata
    Vaitkevičienė, Nijole
    Kita, Agnieszka
    Powiązania:
    https://bibliotekanauki.pl/articles/2198686.pdf
    Data publikacji:
    2014-06-30
    Wydawca:
    Instytut Hodowli i Aklimatyzacji Roślin
    Tematy:
    parametry wzrostu i plonu
    preparaty biodynamiczne
    ziemniak o kolorowym miąższu
    biodynamic preparations
    coloured fleshed potato
    growth and yield parameters
    Opis:
    Biodynamic agriculture is one of the organic agricultural farming methods. Different from organic farmers, biodynamic farmers add eight specific preparations (made from cow manure, silica, and various plants) to improve crops growth and nutrient composition. In 2012–2013, in organic farm (Prienai district), potato cultivars with coloured flesh were grown for research. The aim of two years’ research was to evaluate effects of biodynamic (BD) preparations (500 and 501) on the growth and yield parameters of the coloured fleshed potatoes. An experiment included two factors: I — three potato cultivars (purple fleshed — Vitelotte, Blue Congo and red-fleshed Red Emmalie), II — using of BD preparations in field sprays (four treatments: 1. Control without BD preparations; 2. BD preparation 500; 3. BD preparation 501; 4. complex application of BD preparations (500+501). The individual productivities of potato plants were analyzed in the field experiment (chlorophyll content index values of leaves, tuber weight per plant and tuber number per plant). The results revealed that combination of BD preparations (500 + 501) was the best among all the treatments for most of the growth and yield parameters under study. It was found, that, compared with the control variant, combination of BD preparations (500 + 501) substantially increased the chlorophyll content index in leaves, the weight and number of tubers per plant of cvs. Blue Congo and Red Emmalie. BD preparation 501 substantially increased the chlorophyll content index in leaves of Red Emmalie at 9th (1.07 times) and 13th (1.13 times) week, and of Blue Congo only at 9th (1.07 times) week after planting. However, more research is needed to determine whether the BD preparations affect growth and yield parameters of colour-fleshed potato tubers.
    Rolnictwo biodynamiczne jest jedną z metod rolnictwa ekologicznego. W uprawie biodynamicznej, w celu poprawy jakości plonu i kompozycji składników odżywczych w surowcu, wykorzystuje się osiem konkretnych preparatów (z nawozu krowiego, krzemionki i różnych roślin). Materiałem użytym do badań były ziemniaki odmian o kolorowym miąższu uprawiane w gospodarstwie ekologicznym (powiat Prienai) w latach 2012–2013. Celem badań było określenie wpływu preparatów biodynamicznych (BD) 500 i 501 na parametry wzrostu i wydajność plonu ziemniaków o kolorowym miąższu. Eksperyment obejmował dwa czynniki: I — odmiany ziemniaka (dwie odmiany ziemniaków z niebieskim miąższem — Blue Congo i Vitelotte oraz jedna z czerwonym — Red Emmalie), II — wykorzystanie preparatów biodynamicznych do oprysków gleby i roślin (cztery zabiegi: 1. kontrola bez preparatów BD 2. z zastosowaniem preparatu biodynamicznego 500; 3. z zastosowaniem preparatu biodynamicznego 501; 4. z zastosowaniem obu preparatów biodynamicznych (500 + 501). Produktywność roślin ziemniaka oznaczano w doświadczeniu polowym (wartość indeksu zawartości chlorofilu w liściach, masę i liczbę bulw pod krzewem). Najlepsze parametry wzrostu uzyskano przy zastosowaniu kombinacji preparatów biodynamicznych (500 + 501). Stwierdzono, że w porównaniu z wariantem kontrolnym stosowanie obu preparatów (500 + 501), istotnie zwiększyło zawartość chlorofilu w liściach oraz masę i liczbę bulw z jednej rośliny w odmianach ziemniaka Blue Congo i Red Emmalie. Preparat 501 istotnie zwiększał wskaźnik zawartości chlorofilu w liściach odmiany Red Emmalie w 9 (1.07 razy) i 13 (1.13 razy) tygodniu, a Blue Congo tylko w 9 (1.07 razy) tygodniu po posadzeniu. Niezbędne są jednakże dalsze badania, które pozwolą na ustalenie czy preparaty biodynamiczne istotnie wpływają na parametry wzrostu i plonowanie bulw ziemniaka o kolorowym miąższu.
    Źródło:
    Biuletyn Instytutu Hodowli i Aklimatyzacji Roślin; 2014, 272; 73-79
    0373-7837
    2657-8913
    Pojawia się w:
    Biuletyn Instytutu Hodowli i Aklimatyzacji Roślin
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effects of different hormonal treatments on growth parameters and secondary metabolite production in organ culture of Hyssopus officinalis L.
    Autorzy:
    Shoja, H.M.
    Shishavan, H.K.
    Powiązania:
    https://bibliotekanauki.pl/articles/2096354.pdf
    Data publikacji:
    2021
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    growth parameters
    Hyssopus officinalis
    photosynthetic pigment
    secondary metabolite
    thidiazuron
    Opis:
    Hyssopus officinalis L. is a medicinal plant containing valuable phytochemicals and is used extensively in the pharmaceutical industry. As this plant naturally contains low levels of these metabolites, plant cell and tissue culture technologies are used to produce them in large volumes. The present study aimed first to evaluate the effects of different types of cytokinins, including benzyl adenine (BA), kinetin (KIN), and thidiazuron (TDZ), at 1 ppm concentration in the culture medium on growth parameters and production of secondary metabolites and photosynthetic pigments in organ culture of H. officinalis; in the second step, the study investigated the effect of different concentrations (0, 0.2, 1, 1.5, and 2 ppm) of the most effective type of cytokinin. The results showed that TDZ was the optimal type of growth regulator compared to BA and KIN as it showed a positive influence on the studied traits; furthermore, its highest concentration of 2 ppm in culture medium was determined to be the best one that enabled the highest production of secondary metabolites and photosynthetic pigments. We conclude that the presence of growth regulators can strongly influence the growth and development of plants in tissue culture conditions.
    Źródło:
    BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology; 2021, 102, 1; 33-41
    0860-7796
    Pojawia się w:
    BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effects of grey water irrigation on the cultivation of African spinach (Amaranthus hybridus)
    Autorzy:
    Nwaokobia, K.
    Ogboru, R. O.
    Idibie, C. A.
    Powiązania:
    https://bibliotekanauki.pl/articles/1112546.pdf
    Data publikacji:
    2018
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    African spinach
    Agronomic and Growth parameters
    Amaranthus hybridus
    Grey water
    Irrigation
    Opis:
    Water is a limited resource, hence there is a need for its judicious use. This study was designed to investigate the utilization and the effects of grey water irrigation on the growth parameters of African spinach (Amaranthus hybridus) and its soil properties when planted in a green house. The irrigation treatment consisted of Tap water (TW) and grey water (GW) collected from Akindeko Hostel in Federal University of Technology, Akure. The vegetables were planted in five bucket samples for each irrigation treatment. The water samples were assessed to determine chemical properties, while soil samples were collected and analysed before irrigation application and after harvest. Crop morphology that includes the plant height, number of leaves and stem girth parameters were recorded weekly after emergence. Our results indicate that the grey water type has the highest chemical parameters. These included TSS, SAR, pH, HCO3ˉ, Ca2+, Mg2+, and Na+. What is more, soil pH decreased in all the soil samples after the different water applications, the lowest pH being from grey water. The sodium adsorption ratio (SAR) also decreased in all the irrigation treatments. In addition, the plant height, number of leaves and stem girth of the crop were affected by the water type used. Herein, the crop irrigated with grey water had the highest morphology parameters. Furthermore, soil chemical properties were significantly affected by the use of grey water, hence, appropriate wastewater treatment and water management practices have to be followed to remove the toxic elements that could be hazardous to human health when crops produced on them are consumed.
    Źródło:
    World News of Natural Sciences; 2018, 18, 2; 133-145
    2543-5426
    Pojawia się w:
    World News of Natural Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Evaluation of growth performance of common bean (Phaseolus vulgaris L.) genotypes during two phenological phases
    Autorzy:
    Gebeyehu, Yeshiwas Sendekie
    Powiązania:
    https://bibliotekanauki.pl/articles/1059435.pdf
    Data publikacji:
    2019
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    Biomass yield
    Correlation and Growth parameters
    Phaseolus vulgaris
    Opis:
    Genotypic differences in biomass yield of many crops are mainly associated with variations in leaf area. Physiological growth analysis is the important in prediction of the performance of genotypes during plant growth. Therefore, the field experiment was conducted to study growth characteristics of common bean genotypes at Hawassa university agriculture research site. Three genotypes including Red Wolayita, Hawassa Deme and Ibado were evaluated in randomized complete block design with four replications during 2017 using irrigation. Growth analysis was done using primary data from two successive samplings in 20 days interval during linear vegetative growth stage and flowering stage. Growth parameters, specific leaf area (SLA), leaf area ratio (LAR), leaf area ratio (LAI), net assimilation rate (NAR), crop growth rate (CGR), relative growth rate (RGR) and biomass yield and their correlation were determined. The study result revealed that, Red Wollita had the highest specific leaf area (241.975 cm2 g-1) and leaf area ratio (161.36 cm2 g-1), Hawassa Deme had the highest net assimilation rate (27.5 mg dm-2 Day-1), leaf area index (1.35), relative growth rate (48.02 gg-1 day-1), average growth rate (0.1g day-1), crop growth rate (0.03g m-2 day-1) and biomass yield (2989.6 kg/ha). The ANOVA result indicated that, there was highly significant difference (p < 0.01) among genotypes for biomass yield. Correlation of major growth parameters with biomass yield was investigated. Biomass yield had positively highly correlated with net assimilation rate, absolute growth rate, relative growth rate and crop growth rate with correlation coefficient of (r = 0.39, 0.33, 0.42 and 0.56), respectively.
    Źródło:
    World Scientific News; 2019, 128, 2; 171-181
    2392-2192
    Pojawia się w:
    World Scientific News
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Hodowlane i ekonomiczne aspekty produkcji materiału sadzeniowego z zakrytym systemem korzeniowym poddanego zabiegowi sterowanej mikoryzacji
    Silvicultural and economic aspects of container-grown seedling production subjected to controlled mycorrhization
    Autorzy:
    Szabla, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/1011916.pdf
    Data publikacji:
    2009
    Wydawca:
    Polskie Towarzystwo Leśne
    Tematy:
    szkolkarstwo lesne
    rozwoj roslin
    przezywalnosc
    wzrost roslin
    mikoryzowanie sadzonek
    sadzonki z zakrytym systemem korzeniowym
    produkcja sadzonek
    lesnictwo
    container−grown seedling
    mycorrhized seedling
    growth and development parameters
    Opis:
    This study focuses on the variation in the growth and development parameters of seedlings and their survival in plantations in relation to the degree of soil degradation and seedling production method. Seedlings were planted on former agricultural land, industry damaged forest zones II and III, burnt areas, reclaimed sand mine excavations and industrial soils. The material used in the study comprised container−grown seedlings mycorrhized with the fungus Hebeloma crustuliniforme and Laccaria bicolor, seedlings not subjected to controlled mycorrhization and field−grown bare−root seedlings.
    Źródło:
    Sylwan; 2009, 153, 04; 253-259
    0039-7660
    Pojawia się w:
    Sylwan
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Investigation of growing grains in microstructure of the 61SiCr7 spring steel
    Autorzy:
    Królicka, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/1189961.pdf
    Data publikacji:
    2018
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    rozmiar ziarna
    rozrost ziarna
    mikrostruktura
    stal 61SiCr7
    bainit
    stal krzemowa
    parametry obróbki cieplnej
    grain size
    grain growth
    microstructure
    61SiCr7 steel
    bainite
    Si-rich steel
    heat treatment parameters
    Opis:
    The article presents results from determination of a grain size in microstructure of the 61SiCr7 (60C2A) spring steel. The material was selected with respect to the possibility of obtaining a nano-structured bainite without carbide precipitates. This was conducted basing on an influence of grain size on bainitic transformation time, microstructure and mechanical properties of the material type considered. The experiments indicated, that the addition of silicon caused difficulties related to revealing the grain boundaries of the austenite. Optimal parameters of heat treatment, which enable to reach the microstructure for observing grain sizes of the steel are shown. The growing grains of the tested steel was followed at five values of austenitizing temperature.
    Źródło:
    Interdisciplinary Journal of Engineering Sciences; 2018, 6, 1; 44--47
    2300-5874
    Pojawia się w:
    Interdisciplinary Journal of Engineering Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The growth of seven Abies grandis provenances in the climatic conditions of the Polish Carpathian Mountains
    Autorzy:
    Wilczynski, S.
    Kulej, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/2077766.pdf
    Data publikacji:
    2019
    Wydawca:
    Polska Akademia Nauk. Instytut Dendrologii PAN
    Tematy:
    grand fir
    dendrochronology
    dendroclimatology
    survival
    growth parameters
    Opis:
    The introduction of foreign tree species to new areas facilitates an increase in species biodiversity and possibilities for growth of tree stands. Many years of research related to survival rate, basic growth features and evaluation of a sensitivity to climatic conditions of a new habitat is necessary to achieve a successful introduction. The paper presents the results of the research on the adaptation of grand fir to the climatic conditions in the provenance trial located in the lower montane forest belt. The dendroclimatic research has concerned the offsprings of 7 grand fir provenances originated from North America. A total of 24 trees from each provenance were selected and two cores from each tree were taken. Principal component analysis of tree-ring widths was used to classify the provenances. The climate elements described by PC1 and PC2 were identified on the basis of bootstrap correlation function. Survival rate, height and diameter at breast height of trees were also analysed. The features of the studied provenances showed significant differences. The variation of the inter-provenance survival rate and the increase in tree height of particular provenances were determined principally by the genotype. Grand firs trees from Region I exhibited superior survival rates and better dynamic increases in tree height. The variability of these two features had the character of clinal variation because they primarily depended on the elevation and the latitude of the maternal tree stands. Two groups of provenances which were connected with the regions of their natural distribution were characterized on the basis of the features of the short-term rhythm of the radial increments. The provenances of two specific groups revealed different sensitivity to temperature, rainfall, humidity and sunshine. The greatest effect on the variation of radial increments had been produced by the moisture and pluvial factors whilst the solar factor had produced the least effect on it. The air temperature made also a relatively high contribution to their radial increments. Grand fir trees from the Salmon River provenance in British Columbia provided the best trees from the cultivation point of view. The provenances from Vancouver Island and the western slope of the Cascadian Mountains in Washington State have been regarded as the best for introducing and acclimatising to the conditions of the Carpathian Mts.
    Źródło:
    Dendrobiology; 2019, 81; 1-13
    1641-1307
    Pojawia się w:
    Dendrobiology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Wielocechowa ocena potomstwa populacji buka zwyczajnego (Fagus sylvatica L.) z południowo-wschodniej Polski w początkowych latach wzrostu
    Multivariable evaluation of the early growth performance of European beech (Fagus sylvatica L.) provenances from south-eastern Poland
    Autorzy:
    Buraczyk, W.
    Szeligowski, H.
    Studnicki, M.
    Drozdowski, S.
    Bielak, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/989437.pdf
    Data publikacji:
    2016
    Wydawca:
    Polskie Towarzystwo Leśne
    Tematy:
    lesnictwo
    hodowla lasu
    drzewa lesne
    buk zwyczajny
    Fagus sylvatica
    proweniencje
    drzewa potomne
    przezywalnosc
    wzrost roslin
    cechy fenologiczne
    jakosc hodowlana
    doswiadczenia proweniencyjne
    Nadlesnictwo Losie
    genetic variability
    growth parameters
    morphological traits
    phenology
    progeny testing
    Opis:
    European beech is one of the most important broadleaved tree species in Poland and will play probably even more significant role in the future due to the predicted climate change. The main objectives of this study was to analyse and compare the growth parameters and morphological traits between 23 European beech provenances from south−eastern Poland (fig. 1). The research was conducted on the experimental plot established in Łosie Forest District in 2006. The experiment employed a randomized complete block design consisting of 92 plots (23 provenances×4 blocks). On each plot 100 trees representing given provenance were planted in 1.5×1.5 m spacing. In the spring and autumn 2015 we measured and determined the following parameters for the subsample of 36 trees on each plot: survival rate, tree height, diameter at breast height, diameter of the branch at the middle height of the crown length, stem straightness, crown shape, tendency to create forks, mean angle between stem and branches and spring phenology. We also included different eco−physiographical characteristics for each provenances (tab. 1). We performed basic statistics to describe mean values and standard errors (fig. 2, tab. 2) and finally we quantified the interaction between traits and eco−physiographical characteristics by Principal Component Analysis (PCA) (fig 3, tab. 3). The obtained results indicates that under growth conditions on experimental trial in Łosie Forest District, the provenances from lower elevated regions with lower precipitation and higher mean temperature (i.e. more arid conditions; Kielce and Narol provenances) were characterized by thicker dbh and branch dimeters in contrast to regions from southern Poland (Łosie, Bricza 1, Stary Sącz and Nawojowa). European beech provenances from regions with more humid conditions and lower mean annual temperature, as well as shorter vegetation season are characterized by higher survival rate. They are also higher than other provenances, but reveal the lower ratio dbh to branch diameter.
    Źródło:
    Sylwan; 2016, 160, 12; 981-992
    0039-7660
    Pojawia się w:
    Sylwan
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Właściwości poliamidu PA 12 w aspekcie warunków technicznych projektowania, budowy i eksploatacji gazociągów o MOP 1,6 MPa
    PA12 polyamide properties in the aspect of technical conditions for design, construction and operation of gas pipelines with MOP 1.6 MPa
    Autorzy:
    Szewczyk, Piotr
    Powiązania:
    https://bibliotekanauki.pl/articles/1834968.pdf
    Data publikacji:
    2019
    Wydawca:
    Instytut Nafty i Gazu - Państwowy Instytut Badawczy
    Tematy:
    gazociąg
    właściwości poliamidu PA 12
    wytrzymałość długoczasowa
    maksymalne ciśnienie robocze
    powolna propagacja pęknięć
    zaciskanie
    parametry zgrzewania
    próba szczelności
    gas pipeline
    polyamide PA12 properties
    long-term resistance
    maximum operating pressure
    slow crack growth
    squeeze-off
    welding parameters
    leak test
    Opis:
    Zasadniczą zaletą poliamidu PA 12 jest możliwość jego stosowania do budowy gazociągów o MOP = 1,6 MPa, tj. w zakresie ciśnień, dla którego w Polsce gazociągi budowane są wyłącznie z rur stalowych. Budowa gazociągów z materiałów innych niż stal i polietylen nie jest w Polsce możliwa ze względu na ograniczenia prawne (Rozporządzenie Ministra Gospodarki z dnia 26 kwietnia 2013 r. w sprawie warunków technicznych, jakim powinny odpowiadać sieci gazowe i ich usytuowanie). Obecnie trwają prace nad nowelizacją tego rozporządzenia, które między innymi mają umożliwić dopuszczenie do stosowania innych materiałów i technologii wykorzystywanych w Europie i na świecie. Do zapewnienia bezpiecznej budowy i eksploatacji sieci gazowych z nowych materiałów sama zmiana w przepisach nie jest jednak wystarczająca. W artykule opisano wybrane właściwości poliamidu PA 12 i powiązane z nimi warunki projektowania, budowy i eksploatacji gazociągów. Przedstawiono podstawowe kryteria wyznaczania maksymalnego ciśnienia roboczego, uwzględniające wytrzymałość długoczasową oraz zjawisko szybkiej propagacji pęknięć. Opisano zjawisko powolnej propagacji pęknięć oraz sposób sprawdzania odporności rur z PA 12 na jego wystąpienie, jak i wynikające z niego dopuszczalne uszkodzenia powierzchni rur. Przedstawiono warunki, jakie należy brać pod uwagę podczas transportu i składowania, uwzględniając odporność rur z PA 12 na promieniowanie UV. Ze względu na posiadaną właściwość, jaką jest elastyczność rur, opisano warunki zmiany kierunku gazociągu bez stosowania dodatkowych kształtek kątowych. Wskazano na możliwość zamykania przepływu gazu metodą zaciskania oraz zwrócono uwagę na konieczność zachowania większej ostrożności podczas prac eksploatacyjnych wtemperaturach ujemnych ze względu na spadek elastyczności rur. Przedstawiono podstawowe parametry procesu zgrzewania doczołowego, które różnią się od tych stosowanych przy łączeniu rur i kształtek z PE. Zwrócono uwagę na konieczność modyfikacji parametrów dostępnych procedur prowadzenia prób szczelności wynikającą z większej sztywności obwodowej rur PA 12 niż PE.
    The main advantage of PA12 polyamide is that it can be used in the construction of gas pipelines with MOP = 1.6 MPa, i.e. in the pressure range where in Poland gas pipelines are built exclusively from steel pipes. Construction of gas pipelines from materials other than steel and polyethylene is not possible in Poland due to legal restrictions (Regulation of the Minister of Economy of 26 April 2013 on technical conditions to be met by gas networks and their location). Currently, work is underway on the amendment of this regulation, which among others, is to allow for the use of other materials and technologies used in Europe and in the world. However, the legislative amendment alone is not sufficient to ensure the safe construction and operation of gas networks from new materials. The article presents selected properties of PA12 polyamide and associated conditions for the design, construction and operation of gas pipelines. The basic criteria for determining the maximum operating pressure including long-term resistance and the phenomenon of rapid crack propagation are presented. The phenomenon of slow crack growth and the method of testing the resistance of PA12 pipes to its occurrence as well as the resulting acceptable damages to pipe surfaces are described. The article presents the conditions to be considered during transport and storage taking into account the resistance of PA12 pipes to UV radiation. Due to the flexibility of pipes, the conditions for changing the direction of the gas pipeline without the use of additional angle fittings were described. The possibility of closing the gas flow by the clamping method was pointed out and attention was paid to the necessity of greater caution during operating works at negative temperatures due to a decrease in the flexibility of the pipes. The basic parameters of the butt welding process were presented, which differ from those used when connecting PE pipes and fittings. Attention was paid to the necessity to modify the parameters of available procedures for conducting leak tests due to higher circumferential stiffness of PA12 pipes compared to PE ones.
    Źródło:
    Nafta-Gaz; 2019, 75, 11; 708-714
    0867-8871
    Pojawia się w:
    Nafta-Gaz
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Wzrost jodły (Abies alba Mill.) rosnącej w rzędach i na placówkach po całkowitym uprzątnięciu przebudowywanego negatywnego drzewostanu sosnowego (Pinus sylvestris L.)
    Growth of silver fir [Abies alba Mill.] growing in rows and spots after complete removal of negative pine [Pinus sylvestris L.] stand under transformation
    Autorzy:
    Jaszczak, R.
    Magnuski, K.
    Małys, L.
    Powiązania:
    https://bibliotekanauki.pl/articles/1013054.pdf
    Data publikacji:
    2008
    Wydawca:
    Polskie Towarzystwo Leśne
    Tematy:
    biogrupy
    rzedy
    jodla pospolita
    drzewostany sosnowe
    wskaznik ubytku drzew
    wzrost roslin
    Abies alba
    przebudowa drzewostanow
    lesnictwo
    drzewostany negatywne
    urzadzanie lasu
    drzewa lesne
    silver fir
    rows
    spots
    growth parameters
    Opis:
    The paper constitutes a successive study devoted to the stand transformation. It provides comparative results of the assessment of the breast height diameter thickness, height and biological structure of silver fir (Abies alba Mill.) planted 43 years ago in rows and spots under the canopy of a negative pine (Pinus sylvestris L.) stand subjected to transformation. At the present, following cleaning thinning, fir forest is growing without its protection.
    Źródło:
    Sylwan; 2008, 152, 12; 3-8
    0039-7660
    Pojawia się w:
    Sylwan
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-12 z 12

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