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    Wyświetlanie 1-15 z 15
    Tytuł:
    Hierarchy of plasticity traits in responses of Quercus aliena to light conditions and water availability
    Autorzy:
    Xu, N.
    Wang, R.
    Liu, J.
    Lu, P.
    Guo, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/41404.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Instytut Dendrologii PAN
    Opis:
    This study aimed to investigate plasticity of different plant traits to varied light and water availability. A greenhouse experiment was conducted with Quercus aliena seedlings with two light and four soil water levels. Plant traits related to leaf physiology, morphology, anatomy, and biomass production were determined. The results showed that plant size had significant effects on leaf area, leaf number, shoot height, basal diameter and crown area. After excluding the influence of plant size, water treatment had stronger effects on plants compared to light levels, and their interaction effect was significant. The limited water supply significantly inhibited leaf photosynthetic rate and the fluorescence efficiency under high light. However, leaves submitted to moderate drought stress showed enhanced fluorescence activity under shade condition. Grand plasticity of leaf physiology and growth was the highest, followed by biomass allocation and leaf morphology, and lastly anatomy, and this ranking did not change as resources considered. Among the variables, leaf petiole length, chlorophyll content and leaf area could be selected as candidates for estimation of species’ plasticity to water, light and their interaction, respectively. Therefore, our results suggested that there was a hierarchy existing among traits plasticity in Q. aliena, and supported the aboveground facilitation hypothesis that shade could alleviate the adverse effect of drought.
    Źródło:
    Dendrobiology; 2015, 74
    1641-1307
    Pojawia się w:
    Dendrobiology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Abundance and community structure of ammonia oxidizing archaea and bacteria in response to peanut growth under controlled condition in Shandong, China
    Autorzy:
    Huang, C.
    Xu, N.
    Fu, Z.
    Sun, B.
    You, S.
    Ma, D.
    Yu, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/12689395.pdf
    Data publikacji:
    2019
    Wydawca:
    Uniwersytet Przyrodniczy w Lublinie. Wydawnictwo Uniwersytetu Przyrodniczego w Lublinie
    Tematy:
    China
    plant cultivation
    peanut
    Arachis hypogaea
    plant growth
    community structure
    microorganism abundance
    ammonia-oxidizing bacteria
    ammonia-oxidizing archaea
    field experiment
    three-year field experiment
    controlled condition
    Opis:
    Based on a three-year field experiment under controlled condition in Ji’nan, China, the effects of peanut growth on the variation in the abundance and community structure of ammonia oxidizing bacteria (AOB) and archaea (AOA) before and after peanut growth were investigated through quantitative PCR and cluster analysis of terminal-restriction fragment length polymorphism. Our results show that the community composition of AOA and AOB was greatly affected by the peanut growth leading to the decreased abundance of AOA and increased abundance of AOB. Furthermore, AOA and AOB community structures varied before and after peanut growth. Phylogenetic analysis indicated that all AOA and AOB community sequences were clustered into the uncultured group. Altogether, the results suggested that the abundance of AOA and AOB in soil and their community compositions can be greatly affected by the peanut growth.
    Źródło:
    Acta Scientiarum Polonorum. Hortorum Cultus; 2019, 18, 6; 119-127
    1644-0692
    Pojawia się w:
    Acta Scientiarum Polonorum. Hortorum Cultus
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Biomass partition and carbon storage of Cunninghamia lanceolata chronosequence plantations in Dabie Mountains in East China
    Autorzy:
    Xie, X.
    Cui, J.
    Shi, W.
    Liu, X.
    Tao, X.
    Wang, Q.
    Xu, X.N.
    Powiązania:
    https://bibliotekanauki.pl/articles/41359.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Instytut Dendrologii PAN
    Tematy:
    biomass
    carbon storage
    Cunninghamia lanceolata
    Chinese fir
    chronosequence
    plantation forest
    Dabie Mountains
    China
    Opis:
    The quantification of biomass carbon pools is important for understanding carbon cycling in forest ecosystems. This study was designed to reveal the effects of stand age on biomass partitioning and carbon storage of Chinese fir plantation stands in Dabie Mountains of Anhui, East China. A total of six even-aged Chinese fir plantation stands along an age-sequence from 10 to 50 years were selected. To quantify the biomass of different tree components, 18 trees with diameter at breast height (D1.3) from 6.5 to 35.2 cm were harvested from the different aged stands. Biomasses of understory vegetation, forest floor and standing dead trees were also investigated. Total biomass carbon storages ranged from 57.6 to 211.4 Mg ha–1 in the different aged stands. Tree layer comprised from 93.7% to 96.4% of the total biomass C pools in the different aged stands. The C pools of the necromass were from 1.8 to 6.2 Mg ha–1. Stand age had a significant effect on tree biomass partitioning, with an increase in proportion of root biomass. The root/shoot ratios were from 0.187 to 0.312, which was significantly positively correlated to stand age. The existing plantation stands are still developing and have somewhat high rate of biomass and carbon accumulations beyond the normal rotation period (usually 25–30 years) even over an age of 50 years. Appropriate prolongation of the rotation period of Chinese fir plantation will be effective in maintaining long-term productivity and providing large carbon sink. The measurements provide valuable data for modelling productivity of Chinese fir plantation forest.
    Źródło:
    Dendrobiology; 2016, 76
    1641-1307
    Pojawia się w:
    Dendrobiology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Reconstruction of oviraptorid clutches illuminates their unique nesting biology
    Autorzy:
    Yang, T.-R.
    Wiemann, J.
    Xu, L.
    Cheng, Y.-N.
    Wu, X.-C.
    Sander, P.M.
    Powiązania:
    https://bibliotekanauki.pl/articles/19933.pdf
    Data publikacji:
    2019
    Wydawca:
    Polska Akademia Nauk. Instytut Paleobiologii PAN
    Opis:
    Oviraptorosaurs, a group of non-avian theropod dinosaurs from the Cretaceous of Asia and North America, left behind the most abundant and informative fossil evidence of dinosaur reproductive biology. Previous studies had suggested that oviraptorosaur reproductive biology represents an intermediate stage and exhibited unique modern avian traits. For instance, the adult-associated clutches were predominantly considered as evidence for brooding/thermoregulatory contact incubation (TCI) behaviors, whereas the hypotheses of laying or protection were neglected. Despite numerous oviraptorid egg clutches uncovered from China and Mongolia, their nest architecture and clutch arrangement were rarely investigated in detail. Here we present a comprehensive reconstruction of an oviraptorid clutch based on five new oviraptorid clutches from Jiangxi Province, China. A detailed examination of the new clutches reveals a partially-open oviraptorid nest that contains 3–4 rings of paired eggs (more than 15 pairs total) whose blunt end points toward the center devoid of eggs at an angle of 35–40°. Our detailed three-dimensional reconstruction indicates that the oviraptorid clutch has a unique architecture unknown from extant bird clutches, implying an apomorphic nesting mode. Such a unique nest architecture further contradicts the TCI hypothesis in oviraptorids, hindering sufficient heat transfer to the inner (lower) ring(s) of eggs. Moreover, the size of the new oviraptorid clutches (>30 eggs) is significantly larger than that of the adult-associated clutches (<22 eggs), raising the alternative hypothesis that the adult-associated clutches were uncompleted. This clue thus supports the hypothesis that the clutch-associated oviraptorid adults possibly represent females after an oviposition before a catastrophic sandstorm/flooding burial.
    Źródło:
    Acta Palaeontologica Polonica; 2019, 64, 3
    0567-7920
    Pojawia się w:
    Acta Palaeontologica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Structural and Optical Properties of ZnO Nanowires Doped with Magnesium
    Autorzy:
    Zhuang, H.
    Wang, J.
    Liu, H.
    Li, J.
    Xu, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/1505046.pdf
    Data publikacji:
    2011-06
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.46.Km
    61.72.uj
    81.15.Gh
    78.67.-n
    Opis:
    ZnO nanowires doped with Mg have been successfully prepared on Au-coated Si (111) substrates using chemical vapor deposition method with a mixture of ZnO, Mg, and activated carbon powders as reactants at 850°C. The structural, compositional, morphological and optical properties of the samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy, and photoluminescence spectroscopy. The nanowires are single crystalline in nature and preferentially grow up along [0001] direction with the average diameter and length of about 60 nm and several hundred micrometers, respectively, thinner and longer than the results of literature using the similar method. Room temperature photoluminescence spectroscopy shows a blueshift from the bulk band gap emission, which can be attributed to Mg doping that were detected by energy dispersive X-ray analysis EDX in the nanowires. Finally, the possible growth mechanism of crystalline ZnO nanowires is discussed briefly.
    Źródło:
    Acta Physica Polonica A; 2011, 119, 6; 819-823
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Two New and Two Poorly Known Species of Ancistrum (Ciliophora, Scuticociliatia, Thigmotrichida) Parasitizing Marine Molluscs from Chinese Coastal Waters of the Yellow Sea
    Autorzy:
    XU, Kuidong
    Song, Weibo
    Warren, Alan
    Powiązania:
    https://bibliotekanauki.pl/articles/763756.pdf
    Data publikacji:
    2015
    Wydawca:
    Uniwersytet Jagielloński. Wydawnictwo Uniwersytetu Jagiellońskiego
    Tematy:
    Ancistrum haliotis n. sp., Ancistrum crassum, Ancistrum acutum n. sp., Ancistrum japonicum, marine parasitic ciliate, morphology, neotype, new species, taxonomy
    Opis:
    The morphology and taxonomy of two new and two poorly known ciliate species of Ancistrum, found in the mantle cavity (mainly on gills) of marine molluscs from culture beds and pools along the Chinese coast of the Yellow Sea, were investigated using living observation and silver impregnation. Ancistrum haliotis n. sp. was isolated from the abalone Haliotis discus hannai Ino, A. crassum Fenchel, 1965 from the purple clam Saxidomus purpuratus (Sowerby), A. acutum n. sp. from the surf clam Mactra veneriformis Reeve, and A. japonicum Uyemura, 1937 from both the venus clam Cyclina sinensis (Gmelin) and from Dosinia japonica (Reeve). Ancistrum haliotis differs from its most similar relative A. mytili (Quennerstedt, 1867) by the body outline (anterior portion narrower vs. wider than the posterior portion), the macronuclear shape (broadly ellipsoidal vs. reniform or sausage-like), and by having fewer somatic kineties (28–32 vs. usually more than >40). Ancistrum crassum is characterized by the naked area at the apical end of the cell, the relatively short buccal field occupying about two thirds of the body length, and the posterior-dorsal cone-shaped prolongation. Ancistrum acutum n. sp. and A. japonicum are almost identical in morphometry, but differ distinctly in the live morphology (anterior end pointed and posterior end rounded vs. anterior end narrowly rounded and posterior-dorsal end protruded) and ciliary pattern (all right-side kineties extend to posterior body end vs. all right-side kineties excluding somatic kinety 1 distinctly shortened posteriad, forming a glabrous zone). We neotypify Ancistrum japonicum and discuss the taxonomic status of the four species. Based on an evaluation of all nominal species of Ancistrum and Ancistrumina, we recognize nine valid species of Ancistrum and provide a tabular guide to their identification. Fenchelia Raabe, 1970 is regarded as a junior synonym of Ancistrum Maupas, 1883. We synonymize Ancistrumina nucellae Khan, 1970 with Ancistrum japonicum Uyemura, 1937 and Ancistrum edajimanum Oishi, 1978 with A. crassum Fenchel, 1965.
    Źródło:
    Acta Protozoologica; 2015, 54, 3
    1689-0027
    Pojawia się w:
    Acta Protozoologica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    An articulated pes from a small parvicursorine alvarezsauroid dinosaur from Inner Mongolia, China
    Autorzy:
    Hone, D.W.E.
    Choiniere, J.N.
    Tan, Q.
    Xu, X.
    Powiązania:
    https://bibliotekanauki.pl/articles/21549.pdf
    Data publikacji:
    2013
    Wydawca:
    Polska Akademia Nauk. Instytut Paleobiologii PAN
    Tematy:
    paleontology
    Dinosauria
    Theropoda
    maniraptoran
    arctometatarsalian organism
    Cretaceous
    Inner Mongolia
    alvarezsauroid dinosaur
    dinosaur
    China
    Opis:
    A near complete and articulated parvicursorine pes from the Campanian Wulansuhai Formation is described. This pes is referred to the genus Linhenykus and is one of the first foot skeletons to be described for a derived alvarezsaur, providing new information on the first digit of the pes. The evolution of a laterally directed flange of the anterior face of the distal third metatarsal in arctometatarsalian taxa is described and discussed. This flange may have increased stability of the foot during cursorial locomotion and may also provide useful taxonomic and systematic data.
    Źródło:
    Acta Palaeontologica Polonica; 2013, 58, 3
    0567-7920
    Pojawia się w:
    Acta Palaeontologica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    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 effect of injection pressure and strategy in a Jaguar V6 diesel engine
    Autorzy:
    Abdullah, N. R.
    Mamat, R.
    Rounce, P.
    Wyszynski, M. L.
    Tsolakis, A.
    Xu, H. M.
    Tian, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/242414.pdf
    Data publikacji:
    2009
    Wydawca:
    Instytut Techniczny Wojsk Lotniczych
    Tematy:
    combustion
    emissions
    injection strategies
    premixed combustion
    ignition delay
    Opis:
    In recent years, the improvement of engine performance and emissions has become an extremely important concern. This study focuses on the injection strategy based on the injection pressure (IP) and duration between pilot injection and the main injection (dMI) using a multi cylinder common rail multiple injections diesel engine. The study was designed to produce improvements in fuel mixing via the injection strategy, to reduce the main ignition delay. This would contribute to a minimum amount of fuel burnt in the premixed combustion phase, leading to a reduction in emissions. Recent evidence shows that premixed combustion is significant in the controlling of emissions of nitrogen oxides (NOx) and soot. Six different IPs combined with a short and long dMI were compared in the attempt to improve engine performance and emissions. The engine performance was measured in terms of brake specific fuel consumption, ignition delay, heat release and peak in-cylinder pressure and emissions, specifically nitrogen oxides (NOx), total unburned hydrocarbons (THC), carbon monoxide (CO) and smoke emissions for each engine test condition. The evidence from this study shows that the effect of IP is more dominant than dMI in terms of peak cylinder pressure, heat release, brake specific fuel consumption and emissions. However, the dMI shows a strong effect at a higher engine speed.
    Źródło:
    Journal of KONES; 2009, 16, 2; 9-22
    1231-4005
    2354-0133
    Pojawia się w:
    Journal of KONES
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    HGRP: hybrid grid routing protocol for heterogeneous hierarchical wireless networks
    Autorzy:
    Shen, Y.
    Pei, Q.
    Xu, Q.
    Xi, N.
    Ma, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/206219.pdf
    Data publikacji:
    2012
    Wydawca:
    Polska Akademia Nauk. Instytut Badań Systemowych PAN
    Tematy:
    hybrid grid routing protocol
    mobile ad hoc networks
    heterogeneous wireless networks
    ad hoc on-demand distance vector routing protocol
    zone routing protocol
    Opis:
    The heterogeneous mobile terminals coexist in the next generation wireless networks. The most common routing schemes for mobile ad hoc networks are designed for homogeneous wireless networks. The heterogeneous wireless network routing protocols are needed urgently in many important applications. This paper improves the routing scheme utilizing different capability of terminals and the Hybrid Grid Routing Protocol (HGRP) is proposed. The network is organized in the grid form, that is, the network deployment area is divided into square cells according to the location. Each cell contains one backbone node and several ordinary nodes. This proposed protocol consists of four parts: grid construction, local routing, global routing, and routing correction. Analysis and simulation results indicate that the proposed protocol has the advantages of lower routing cost, lower energy consumption, smaller delay and higher throughput, compared to AODV and ZRP.
    Źródło:
    Control and Cybernetics; 2012, 41, 2; 353-371
    0324-8569
    Pojawia się w:
    Control and Cybernetics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Finite Element Modeling for the Uni-Axial Tensile Behaviour of Metallic Warp-Knitted Fabric
    Zastosowanie metody elementów skończonych (FEM) do przewidywania jednoosiowego rozciągania dzianin metalicznych
    Autorzy:
    Xu, H.-Y.
    Jiang, J.-H.
    Chen, N.-L.
    Lin, F.-B.
    Shao, H.-Q.
    Powiązania:
    https://bibliotekanauki.pl/articles/231781.pdf
    Data publikacji:
    2018
    Wydawca:
    Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
    Tematy:
    warp-knitted fabric
    finite element analysis
    tensile behavior
    metallic
    TexGen
    dzianina osnowowa
    analiza elementów skończonych
    proces rozciągania
    dzianina metaliczna
    Opis:
    The finite element analysis method (FEM), for its advantages of lower time and economic costing in predicting the mechanical properties of fabrics, was applied to warp-knitted fabrics. In this paper, two bar warp-knitted fabric knitted with wires was used as reflecting mesh antennas. Firstly the loop unit of the metallic warp-knitted fabric was simulated in 3-D by TexGen software. Secondly the 3-D loop unit model was inputted into ABAQUS software to form a model of the metallic warp-knitted fabric sheet for uni-axial tension analysis. Thirdly numerical results were obtained after setting the parameters in ABAQUS. Finally numerical results were verified by uni-axial tensile experiments on the metallic warp-knitted fabric. The results showed that the simulation was in good agreement with the experimental tensile process, where the transfer of yarns between loops when in low fabric elongation and in yarn elongation when in high fabric elongation were simulated by FEM of warp-knitted fabric in the tensile process. Also the same trend of tensile force was found in experiment and FEM results. Therefore it can be concluded that FEM can be used to predict the mechanical properties of warp-knitted fabric with a complex structure.
    Do przewidywaniu mechanicznych właściwości dzianin metalicznych zastosowano metodę elementów skończonych (FEM). Symulacji 3D dzianin dokonano przy użyciu dwóch rodzajów oprogramowania: TexGen i ABAQU. Wyniki symulacji zweryfikowano eksperymentalnie. Stwierdzono, że symulacja charakteryzowała się zgodnością z eksperymentalnie przeprowadzonym procesem rozciągania. Na podstawie wyników stwierdzono, że metoda elementów skończonych (FEM) może być z powodzeniem wykorzystywana do przewidywania mechanicznych właściwości dzianin o złożonej strukturze.
    Źródło:
    Fibres & Textiles in Eastern Europe; 2018, 2 (128); 49-54
    1230-3666
    2300-7354
    Pojawia się w:
    Fibres & Textiles in Eastern Europe
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Synthesis and Characterization of a High Energy Combustion Agent (BHN) and Its Effects on the Combustion Properties of Fuel Rich Solid Rocket Propellants
    Autorzy:
    Pang, W.-Q.
    Zhao, F.-Q.
    Xue, Y.-N.
    Xu, H.-X.
    Fan, X.-Z.
    Xie, W.-X.
    Zhang, W.
    Lv, J.
    Deluca, L. T.
    Powiązania:
    https://bibliotekanauki.pl/articles/358474.pdf
    Data publikacji:
    2015
    Wydawca:
    Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
    Tematy:
    fuel rich solid propellant
    BHN
    DSC
    TG-DTG
    burning rate
    combustion properties
    Opis:
    A high energy combustion agent (tetraethylammonium decahydrodecaborate, BHN) was prepared by means of an ion exchange reaction (IER), and the prepared samples were characterized by the advanced diagnostic techniques of Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), Thermogravimetric Analysis (TGA), and Differential Scanning Calorimetry (DSC) etc. The effects of BHN particles on the hazard and combustion properties of fuel rich solid propellants were investigated. The results showed that the BHN samples and fuel rich propellants containing BHN particles can be prepared successfully and solidified safely. The peak temperature of thermal decomposition and the heat of decomposition of the BHN samples prepared were 305.8 °C and 210.9 J•g-1 at a heating rate of 10 K•min-1, respectively. The burning rate and pressure exponent of fuel rich solid propellants decreases with increases in the fraction of BHN particles in the propellant formulation. Compared with the reference formulation (sample BP-1), the burning rate of the propellant with 10% mass fraction of BHN particles (sample BP-4) had decreased 30% at 3.0 MPa, and the pressure exponent had dropped from 0.44 to 0.41.
    Źródło:
    Central European Journal of Energetic Materials; 2015, 12, 3; 537-552
    1733-7178
    Pojawia się w:
    Central European Journal of Energetic Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Cuttings transport with foam in highly inclined wells at simulated downhole conditions
    Transport urobku wiertniczego przy użyciu piany w silnie nachylonych otworach w symulowanych warunkach w otworze
    Autorzy:
    Xu, J.
    Ozbayoglu, E.
    Miska, S.
    Yu, M.
    Takach, N.
    Powiązania:
    https://bibliotekanauki.pl/articles/220081.pdf
    Data publikacji:
    2013
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    piana
    reologia
    transport urobku wiertniczego
    nachylenie
    drążenie odcinków poziomych
    wysokie ciśnienie
    wysoka temperatura
    foam
    rheology
    cuttings transport
    high inclination
    horizontal drilling
    high pressure high temperature
    Opis:
    Along with the rapidly growing demand and development activities in unconventional resources, is the growth of environmental awareness and concerns among the public. Foam, as an alternative to traditional drilling fluid, is gaining more and more momentum in the drilling industry. Drilling with foam can minimize formation damage, water usage, and drag and torque. Foam also costs less and leaves a much smaller environmental footprint than other commonly used drilling fluids, such as synthetic oil-based fluids, when developing vulnerable formations such as shale gas. As drilling in horizontal and near horizontal sections has become very common, and the need for such sections is increasing, it is very important to understand cuttings transport and hole cleaning issues when drilling with foam in such sections. A team from University of Tulsa Drilling Research Projects (TUDRP) conducted a series of experiments focused on studying the effects of change in hole inclination angle from 90 degrees to 70 degrees on cuttings transport with foam under Elevated Pressure and Elevated Temperature (EPET) conditions. This experimental and theoretical study also includes other influential parameters such as foam quality, foam flow rate, polymer concentration and drill pipe rotary speed. We have observed that there is no significant difference in cuttings concentration and frictional pressure losses as inclination changes from 70 to 90 degrees. Also, an increase in superficial foam velocity reduces cuttings concentration within the annulus. Pipe rotation influences cuttings concentration and frictional pressure losses for low quality foams, but does not have a significant effect on high quality foams. A correlation for the cuttings bed area and a computer simulator are developed for practical design and field applications. The predicted results are compared with experimental results from this study and previous studies. The comparison shows good agreement. We believe that the findings of this paper will help designers with the choice of optimal drilling fluid for drilling horizontal wells in unconventional (shale) gas/oil reservoirs.
    Równolegle ze stale rosnącym zapotrzebowaniem na prowadzenia prac udostępniających w złożach niekonwencjonalnych notuje się wzrost świadomości społecznej odnośnie zagadnień ochrony środowiska. Piana jako alternatywa dla tradycyjnej płuczki wiertniczej nabiera coraz większego znaczenia w górnictwie otworowym. Wiercenie przy użyciu piany pomogą ograniczać zniszczenia formacji geologicznych, redukuje zużycie wody, pozwala na zminimalizowanie oporów ruchu i momentów obrotowych silników. Ponadto, koszty piany są niższe a jej oddziaływanie na środowisko naturalne jest mniej znaczne niż w przypadku typowych płuczek opartych na olejach syntetycznych używanych w trakcie udostępniania trudnych w eksploatacji złóż, np. gazu łupkowego. Wiercenia odcinków poziomych lub prawie poziomych są już szeroko stosowane a zapotrzebowanie na takie odcinki wrasta, ważnym jest właściwe rozpoznanie problemów związanych z transportem urobku wiertniczego i czyszczeniem otworu w trakcie prowadzenia prac wiertniczych na tych odcinkach przy użyciu piany. Zespól badaczy z uniwersytetu w Tulsa zaangażowanych w projekt badawczy w dziedzinie wiertnictwa (TUDRP) przeprowadził serię eksperymentów mających na celu zbadanie wpływu zmiany kąta nachylenia otworu z 90 na 70 stopni na przebieg transportu urobku wiertniczego z wykorzystanie piany w warunkach podwyższonego ciśnienia i podwyższonych temperatur. Badania eksperymentalne i teoretyczne obejmowały także analizę pozostałych parametrów procesu: jakość piany, natężenie przepływu piany, stężenie polimerów, prędkość obrotowa przewodu wiertniczego. Nie stwierdzono znacznych różnic w stężeniu zwiercin ani utraty ciśnienia wskutek tarcia w trakcie zmiany kąta nachylenia z 90 na 70 stopni. Ponadto, dodatkowy wzrost prędkości ruchu piany prowadzi do zmniejszenia stężenia zwiercin w pierścieniu. Prędkość obrotowa przewodu wpływa na stężenie zwiercin i straty ciśnienia wskutek tarcia w przypadku stosowania pian niskiej jakości, efektu tego nie notuje się gdy wykorzystywane są wysokiej jakości piany. Dane z obszaru wiercenia skorelowane zostały z wynikami symulacji komputerowych do wspomagania projektowania i do wykorzystania w terenie. Prognozowane wyniki porównano z wynikami eksperymentów uzyskanymi w tym oraz w poprzednim programie badawczym. Porównanie to wykazuje dużą zgodność wyników. Mamy nadzieję, że wyniki obecnej pracy pomogą inżynierom projektantom w wyborze optymalnej płuczki wiertniczej do wierceń poziomych odcinków otworów przy eksploatacji niekonwencjonalnych złóż ropy i gazu (np. gazu łupkowego).
    Źródło:
    Archives of Mining Sciences; 2013, 58, 2; 481-494
    0860-7001
    Pojawia się w:
    Archives of Mining Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    3D Simulation of Warp Knitted Structures with a New Algorithm Based on NURBS
    Symulacja 3D struktur dzianych z zastosowaniem algorytmu opartego na algorytmie NURBS
    Autorzy:
    Xu, H Y
    Chen, N L
    Jiang, J H
    Jin, L X
    Wang, Z X
    Powiązania:
    https://bibliotekanauki.pl/articles/232913.pdf
    Data publikacji:
    2015
    Wydawca:
    Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
    Tematy:
    warp knitted stitch
    three-dimensional simulation
    NURBS
    joint of stitches
    MATLAB
    ścieg osnowy tkaniny
    struktura dzianin
    symulacja trójwymiarowy
    algorytm NURBS
    wspólne szwów
    oprogramowanie Matlab
    Opis:
    In order to obtain a three-dimensional computer simulation of warp knitted structures with more flexibility and realism, a new algorithm using Matlab was developed by NURBS based on empirical geometrical loop models. With the principles of NURBS curves, once the values of data points are known, the control points with two coincidence points at the start and end points can be uncomplicatedly calculated by Matlab. Then the NURBS curve of a single typical stitch can be simulated flexibly by Matlab. A new typical stitch selected from two stitches simulated directly by the new method is redefined to improve the joint of neighboring stitches, and it is found that there are two types of redefined typical warp knitted stitches judged by whether the two under lap on the same side or not. Based on the redefined typical warp knitted stitch, two warp knitted structures are simulated regardless of the loop offset, and all the joints of stitches are smooth.
    Przeprowadzono symulację komputerową struktur dzianin w wymiarze 3D, opracowując w tym celu nową procedurę opartą na algorytmie NURBS. Do tego celu wykorzystano oprogramowanie MATLAB. Symulację 3D przeprowadzono w oparciu o procedury numeryczne umożliwiające wykreślenie przestrzennych figur geometrycznych opisujących strukturę dzianin. Symulowano kształt oczek zamkniętych i otwartych podstawowych splotów kolumienkowych trykotu, sukna i aksamitu. W oparciu o 8 punktów referencyjnych zorientowano konfigurację pętli oczka i łącznika w postaci przestrzennej linii eliptycznej. Do zapisu struktury splotu kształtu oczek wykorzystywano aparat matematyczny w postaci macierzy.
    Źródło:
    Fibres & Textiles in Eastern Europe; 2015, 1 (109); 57-60
    1230-3666
    2300-7354
    Pojawia się w:
    Fibres & Textiles in Eastern Europe
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Mineralizacja polimetaliczna z kopalni Beiyi w okręgu rud żelaza Shilu na wyspie Hajnan w południowych Chinach
    The polymetallic mineralization from the Beiyi mine, Shilu iron ores district, Hainan Island (Southern China)
    Autorzy:
    Mikulski, S.Z.
    Bakun-Czubarow, N.
    Xu, D.
    Wang, Z.
    Powiązania:
    https://bibliotekanauki.pl/articles/2062063.pdf
    Data publikacji:
    2012
    Wydawca:
    Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
    Tematy:
    kruszce
    rudy siarczkowe miedzi i kobaltu
    rudy żelaza
    amalgamat Ag-Hg
    analizy w mikroobszarze
    kopalnia Beiyi
    złoże Shilu
    Wyspa Hajnan
    Chiny
    ore mineralogy
    ores
    copper-cobalt sulfides
    iron oxide
    Ag-Hg amalgamate
    microprobe analyses
    Beiyi mine
    Shilu deposit
    Hainan Island
    China
    Opis:
    W regionie górniczym Shilu posiadającym olbrzymie zasoby rud żelaza typu BIF (Banded Iron Formation), oprócz mineralizacji tlenkami Fe (głównie hematyt), występuje lokalnie w spągu 6 poziomu stratygraficznego grupy Shilu, bogata polimetaliczna mineralizacja siarczkowa Cu–Co. W regionie górniczym Shilu występują słabo zmetamorfizowane skały wulkanoklastyczne i węglanowe zaliczane do mezo- i neoproterozoiku, w które intrudowały różnego wieku granitoidy. Przedmiotem badań mikroskopowych w świetle odbitym i w mikroskopie elektronowym CAMECA SX 100, wyposażonym w przystawkę EDS i WDS, była polimetaliczna mineralizacja kruszcowa z kopalni Beiyi i jej okolic. Mineralizacja kruszcowa, głównie pirotynowo-chalkopirytowa oraz kobaltonośny piryt (do ok. 11% wag. Co), występuje w zmienionych skałach węglanowo-krzemianowych i silnie okwarcowanych skałach diopsydowo-tremolitowych w postaci impregnacji, żyłek i masywnych agregatów ziarnistych. Pirotyn i chalkopiryt zawierają liczne wrostki oraz tworzą przerosty z innymi minerałami (sfaleryt, galena, glaukodot, costibit, kobaltyn, arsenopiryt, ullmannit, siegenit, tytanit, Co-bravoit i kasyteryt). Niewielkie kryształy (10–20 μm średnicy) tworzą minerały Bi (matyldyt i cosalit) i argentyt. W paragenezie z barytem, kalcytem i chlorytem pojawiają się amalgamaty Ag–Hg oraz cynober. Wyniki prac pozwoliły rozpoznać nowe, dotychczas nieopisywane ze złoża minerały. Rezultaty badań wskazują na krystalizację minerałów kruszcowych podczas 4–5 oddzielnych etapów precypitacji kruszców z roztworów hydrotermalnych, w zakresie od temperatur średnich do niskich. Wstępne wyniki oznaczeń wieku izotopowego metodą Re–Os młodszej generacji pirytów (pozbawionych domieszek kobaltu) wskazują na ich precypitację w interwale 240–260 mln lat.
    The famous Shilu iron-polymetallic ore mining district located in western Hainan Island, South China, occurs within Meso- and Neoproterozoic low-grade metamorphosed volcanoclastics and carbonates, that belong to the 6th sequence of the Shilu Group. Granitoid intrusions of different ages occur in the surroundings of the mining area. The Shilu deposit is considered to be a structurally reworked as well as hydrothermally altered and enriched ore deposit of a Banded Iron Formation type. The deposit is a very important iron producer from hematite (and minor magnetite) ores. Our work focused on the polymetallic sulfide mineralization that underlies the iron oxide ores. We selected several samples of sulfide ores from the Shilu deposit of the Beiyi mine and its close vicinity. We performed detailed ore microscopic studies as well as electron microprobe analyses using the CAMECA SX 100 equipped with EDS and WDS systems. Pyrrhotite, chalcopyrite and Co-bearing pyrite (up to 11 wt% Co) dominated among ore sulfides in the studied samples. These ore minerals occur in calc-silicate rocks and strongly silicified diopside, tremolite-bearing rocks, either as disseminated grains, sometimes in veinlets, or in aggregates that may form massive ores. Pyrrhotite and chalcopyrite may contain numerous solid inclusions, overgrowths and intergrowths of subordinate sulfides (sphalerite, galena), sulfosalts (glaucodot, costibite, cobaltite, arsenopyrite, ullmannite), sulfospinels (siegenite) and cassiterite that belong to the minerals crystallizing at medium to low temperatures. Among these minerals, siegenite and Co-bravoite dominate. Tiny crystals (10–20 μm in size) of Bi-minerals (matildite, cosalite) and argentite are also present. Moreover, in association with barite, calcite and chlorite, Ag-Hg amalgamate and cinnabar can occur. The results of our study point to the multistage medium- to low-temperature hydrothermal precipitation of ore sulfides during 4–5 separate stages. Preliminary results of Re-Os isotope datings indicate that pyrites of younger generation (lack of significant Co admixture) crystallized during 240–260 Ma.
    Źródło:
    Biuletyn Państwowego Instytutu Geologicznego; 2012, 452; 181--197
    0867-6143
    Pojawia się w:
    Biuletyn Państwowego Instytutu Geologicznego
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
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