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Tytuł:
Pre-concentration of graphite and LiCoO2 in spent lithium-ion batteries using enhanced gravity concentrator
Autorzy:
Zhu, X,-N.
Tao, Y.-J.
He, Y.-Q.
Zhang, Y.
Sun, Q.-X.
Powiązania:
https://bibliotekanauki.pl/articles/109609.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
spent lithium-ion batteries
electrode material
resource utilization
pre-concentration
enhanced gravity concentrator
Opis:
The pre-concentration of electrode material of spent lithium-ion battery has great significance on the resource utilization and environmental protection. The feasibility of separation of graphite and LiCoO2 based on density difference using the enhanced gravity concentrator was verified in this paper. Combustion characteristics of LiCoO2 and graphite were used to propose a simple evaluation index of separation efficiency. Separation tests were carried out to specify the influence of operating parameters on the separation efficiency. Moreover, the effect of particle size on the separation performance was studied. Combustion characteristics results showed that mass loss of graphite was much greater than that of LiCoO2. Thus, mass loss were used to evaluate the purity of product. Effective separation of graphite and LiCoO2 was achieved by the enhanced centrifugal separator. Separation results showed that increasing centrifugal force decreased the overflow yield and increased the graphite content of the overflow stream. In addition, yield of overflow grew an increase in fluidization water pressure, while the purity of graphite in overflow decreased. The effect of particle size on the separation efficiency was also significant, the separation efficiency decreased with the decreasing of particle size.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 2; 293-299
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical simulation of flow field in enhanced gravity concentrator
Autorzy:
Zhu, X.
Tao, Y.
Zhang, L..
Powiązania:
https://bibliotekanauki.pl/articles/110160.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
numerical simulation
enhanced gravity concentrator
three-dimensional velocity
turbulence characteristics
Opis:
Enhanced gravity concentrator have excellent separation accuracy for the fine mineral particles. However, its internal flow characteristics are still in unclear. Therefore, numerical simulation was conducted to study the flow characteristics of concentrator. Effect of centrifugal force and fluidization water pressure on the velocity component of fluid was studied. The simulation accuracy was verified by the theoretical calculation. The turbulence intensity in the radial direction was analyzed to reveal the gradient characteristics. Results show that the three-dimensional velocity has different order of magnitude. The increase of centrifugal force significantly improves the three-dimensional velocity of fluid. However, the fluidization water pressure has little influence on the tangential velocity and axial velocity, but it can effectively improve the radial velocity. High turbulent flow energy and high turbulence dissipation rate are presented in the near wall region, which allows the light particles reentering the separation region. Meanwhile, the fluid presents stable flow pattern in the fall wall region that is conducive to the stratification process. In addition, the increase of centrifugal force increases the turbulence in the near wall region; however, fluidization pressure has no effect.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 3; 975-980
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Existence Of P≥3-Factor Covered Graphs
Autorzy:
Zhou, Sizhong
Wu, Jiancheng
Zhang, Tao
Powiązania:
https://bibliotekanauki.pl/articles/31341575.pdf
Data publikacji:
2017-11-27
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
P≥3-factor
P≥3-factor covered graph
toughness
isolated toughness
regular graph
Opis:
A spanning subgraph F of a graph G is called a P≥3-factor of G if every component of F is a path of order at least 3. A graph G is called a P≥3-factor covered graph if G has a P≥3-factor including e for any e ∈ E(G). In this paper, we obtain three sufficient conditions for graphs to be P≥3-factor covered graphs. Furthermore, it is shown that the results are sharp.
Źródło:
Discussiones Mathematicae Graph Theory; 2017, 37, 4; 1055-1065
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of zero-valent iron and enzymes on the anaerobic co-digestion of sewage sludge and corn silage
Autorzy:
Zhou, Haidong
Cao, Zhengcao
Ying, Zhenxi
Liu, Jicheng
Hu, Tao
Zhang, Mingquan
Zhang, Jingyuan
Powiązania:
https://bibliotekanauki.pl/articles/2032872.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
corn silage
COD
sewage sludge
anaerobic digestion
kiszonka z kukurydzy
ChZT
osad ściekowy
beztlenowa fermentacja
Opis:
Anaerobic co-digestion of sewage sludge and corn silage with zero-valent iron powder (Fe0), cellulase, and papain as reinforcement means was conducted. COD-based feeding ratio of sewage sludge to corn silage was set to 2:1, the solids retention time (SRT) 20 day, digestion temperature 35 °C, and mixing speed 60 rpm. Removal rates of total COD during the control group, and Fe0, papain, cellulase, and papain, Fe0, and the two kinds of enzyme-added tests were 38.04, 41.02, 34.62, 34.55, 35.42, and 48.21%, respectively. The corresponding biogas production was 2.12, 2.62, 2.22, 2.41, 2.25, and 2.81 dm3/day, respectively. The results indicated the addition of cellulase, and papain could maximize the decomposition and hydrolysis of organic matter in sewage sludge and corn silage to volatile fatty acids. Fe0 could reduce the redox potentials of the anaerobic co-digestion, optimize the circumstances of the methanogenesis stage, accelerate biogas production, and improve biogas components. Fe0 and enzymes played a synergistic role in the anaerobic co-digestion system. Life cycle assessment indicated that the anaerobic co-digestion of sludge and corn silage co-substrates could benefit the economy, environment, and social development under the synergistic action of Fe0 and enzymes.
Źródło:
Environment Protection Engineering; 2020, 46, 4; 41-56
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of zero-valent iron and enzymes on the anaerobic co-digestion of sewage sludge and corn silage
Autorzy:
Zhou, Haidong
Cao, Zhengcao
Ying, Zhenxi
Liu, Jicheng
Hu, Tao
Zhang, Mingquan
Zhang, Jingyuan
Powiązania:
https://bibliotekanauki.pl/articles/2032890.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
corn silage
COD
sewage sludge
anaerobic digestion
kiszonka z kukurydzy
ChzT
osad ściekowy
beztlenowa fermentacja
Opis:
Anaerobic co-digestion of sewage sludge and corn silage with zero-valent iron powder (Fe0), cellulase, and papain as reinforcement means was conducted. COD-based feeding ratio of sewage sludge to corn silage was set to 2:1, the solids retention time (SRT) 20 day, digestion temperature 35 °C, and mixing speed 60 rpm. Removal rates of total COD during the control group, and Fe0, papain, cellulase, and papain, Fe0, and the two kinds of enzyme-added tests were 38.04, 41.02, 34.62, 34.55, 35.42, and 48.21%, respectively. The corresponding biogas production was 2.12, 2.62, 2.22, 2.41, 2.25, and 2.81 dm3/day, respectively. The results indicated the addition of cellulase, and papain could maximize the decomposition and hydrolysis of organic matter in sewage sludge and corn silage to volatile fatty acids. Fe0 could reduce the redox potentials of the anaerobic co-digestion, optimize the circumstances of the methanogenesis stage, accelerate biogas production, and improve biogas components. Fe0 and enzymes played a synergistic role in the anaerobic co-digestion system. Life cycle assessment indicated that the anaerobic co-digestion of sludge and corn silage co-substrates could benefit the economy, environment, and social development under the synergistic action of Fe0 and enzymes.
Źródło:
Environment Protection Engineering; 2020, 46, 4; 41-56
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal error modeling of spindle and dynamic machining accuracy reliability analysis of CNC machine tools based on IA and LHSMC
Autorzy:
Zhang, Ziling
Feng, Shuo
Ding, Yan
Mei, Xiao
Tao, Zhiqiang
Powiązania:
https://bibliotekanauki.pl/articles/2057984.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
electric spindle unit
thermal error
latin hypercube sampling monte carlo method
finite element simulation
machining accuracy reliability
Opis:
Machining accuracy reliability as a key index of CNC machine tools is seriously influenced by the geometric and thermal errors. In the paper, a spindle unit thermal error modeling and machining accuracy reliability analysis method is proposed. By analyzing the heat generation mechanism, a thermal error model was developed to describe the thermal deformation of the electric spindle. Based on the immune algorithm (IA), the heat generation power and the heat transfer coefficient were optimized, and the thermal error was obtained by finite element thermal-mechanical coupling. By adopting the multi-body system theory (MBS), a dynamic machining accuracy model was put forward including the geometric and thermal errors. Based on the Latin hypercube sampling Monte Carlo method (LHSMC), a machining accuracy reliability analysis method was proposed to characterize the machining accuracy reliability considering the geometric and thermal errors. The method was employed to a machine tool, and the experimental results indicate the verification and superiority of the method.
Źródło:
Eksploatacja i Niezawodność; 2022, 24, 1; 100--113
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A gravity flow model of fragmented rocks in longitudinal sublevel caving of inclined medium-thick ore bodies
Model przepływu fragmentów skalnych pod wpływem sił ciężkości przy eksploatacji podpoziomowej złoża rudy o średniej miąższości
Autorzy:
Zhang, Xiufeng
Tao, Ganqiang
Zhu, Zhonghua
Powiązania:
https://bibliotekanauki.pl/articles/218837.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
eksploatacja rud
eksploatacja podpoziomowa
teoria urabiania ośrodka stochastycznego
nachylone złoże o średniej miąższości
profil złoża
ore draw
sublevel caving
stochastic medium draw theory
inclined medium-thick ore body
draw body
Opis:
The draw theory is the foundation for decreasing ore loss and dilution indices while extracting de-posits from mines. Therefore, research on draw theory is of great significance to optimally guide the draw control and improve the economy efficiency of mines. The laboratory scaled physical draw experiments under inclined wall condition conducted showed that a new way was proposed to investigate the flow zone of granular materials. The flow zone was simply divided into two parts with respect to the demarcation point of the flow axis. Based on the stochastic medium draw theory, theoretical movement formulas were derived to define the gravity flow of fragmented rocks in these two parts. The ore body with 55° dip and 10 m width was taken as an example, the particle flow parameters were fitted, and the corresponding theoretical shape of the draw body was sketched based on the derived equation of draw-body shape. The comparison of experimental and theoretical shapes of the draw body confirmed that they coincided with each other; hence, the reliability of the derived equation of particle motion was validated.
Teorie dotyczące urabiania skał stanowią podstawę do działań mających na celu zmniejszenie wielkości strat rudy i wartości opisujących je współczynników w trakcie wybierania złóż. Dlatego też prowadzenie prac teoretycznych ma kluczowe znaczenie dla opracowania optymalnej strategii wybierania i poprawy ogólnej wydajności kopalni. Przeprowadzone eksperymentalne prace wydobywcze w wyrobiskach nachylonych prowadzone w warunkach laboratoryjnych wskazały celowość badania stref przepływu materiałów ziarnistych. Strefę przepływu podzielono na dwie części odpowiednio umiejscowione względem punktu demarkacyjnego na osi przepływu. W oparciu o teorie urabiania dla ośrodka stochastycznego wyprowadzono odpowiednie równania ruchu opisujące przepływ rozdrobnionego materiału skalnego w obydwu tych strefach pod wpływem sił ciężkości. Jako przykład rozpatrywano złoże rudy o nachyleniu 55° i szerokości 10 m, parametry przepływu cząstek skalnych zostały dobrane drogą dopasowania a prognozowany profil złoża wykreślono w oparciu o odpowiednie równania kształtu. Porównanie przewidywanego i rzeczywistego kształtu profilu złoża wykazało ich dużą zbieżność, tym samym potwierdzając wiarygodność opracowanego równania ruchu cząstek skał.
Źródło:
Archives of Mining Sciences; 2019, 64, 3; 533-546
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Geomagnetic detection method for pipeline defects based on ceemdan and WEP-TEO
Autorzy:
Zhang, Tao
Wang, Xinhua
Chen, Yingchun
Shuai, Yi
Ullah, Zia
Ju, Haiyang
Zhao, Yizhen
Powiązania:
https://bibliotekanauki.pl/articles/220762.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
geomagnetic detection
pipeline defects
magnetic field
filtering
data processing
Opis:
This paper presents a geomagnetic detection method for pipeline defects using complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) and wavelet energy product (WEP) - Teager energy operator (TEO), which improves detection accuracy and defect identification ability as encountering strong inference noise. The measured signal is first subtly decomposed via CEEMDAN into a series of intrinsic mode functions (IMFs), which are then distinguished by the Hurst exponent to reconstruct the filtered signal. Subsequently, the scale signals are obtained by using gradient calculation and discrete wavelet transform and are then fused by using WEP. Finally, TEO is implemented to enhance defect signal amplitude, completing geomagnetic detection of pipeline defects. The simulation results created by magnetic dipole in a noisy environment, indoor experiment results and field testing results certify that the proposed method outperforms ensemble empirical mode decomposition (EEMD)-gradient, EEMD-WEP-TEO, CEEMDAN-gradient in terms of detection deviation, peak side-lobe ratio (PSLR) and integrated side-lobe ratio (ISLR).
Źródło:
Metrology and Measurement Systems; 2019, 26, 2; 345-361
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Four stage hybrid constructed wetlands treating low-strength aquaculture wastewater with and without artificial aeration
Autorzy:
Zhang, S.-Y.
Li, G.
Li, X.
Tao, L.
Powiązania:
https://bibliotekanauki.pl/articles/207748.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
wastewater treatment
aquaculture
water pollution
wetlands
aquaculture wastewater
artificial aeration
oczyszczanie ścieków
akwakultura
zanieczyszczenie wody
mokradła
sztuczne napowietrzanie
tereny podmokłe
Opis:
Driven by the booming demands for healthy food, aquaculture industry has to deal with the problem of water pollution appropriately so as to achieve sustainable development. In this study, a combination of four stage CWs (three horizontal subsurface flows followed by one free water surface flow) was configured to treat low-strength aquaculture wastewater. For performance assessment, the wetlands were monitored over three years, during which artificial aeration was added to them. By the results, the organic matters and nutrients were mainly sequestered in the anterior subsurface flows, while the surface flow mainly contributed to DO improvement. These results probably implied no necessity of excessive subsurface flows connected in a staged manner. In addition, the artificial aeration improved the treatment performance on ammonium-N, TN and TP in the first-stage CW.
Źródło:
Environment Protection Engineering; 2015, 41, 3; 31-42
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental study and numerical simulation on fly ash separation with different plate voltages in rotary triboelectrostatic separator
Autorzy:
Zhang, L.
Tao, Y.
Tao, D.
Zhang, W.
Yang, L.
Powiązania:
https://bibliotekanauki.pl/articles/110712.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
fly ash
rotary triboelectrostatic separator
plate voltage
numerical simulation
Opis:
As the main solid wastes of coal-fired power plants, fly ash particles with different electrical properties are usually recycled using triboelectrostatic separator. The purpose of this study was to investigate the effect of different plate voltages on the separation of fly ash in a rotary triboelectrostatic separator with experiments and numerical simulation. The maximum values of yield of ash products (48.30%), and decarbonisation rate (50.89%) and the minimum loss-on-ignition (6.61%) were obtained when the plate voltage was 24 kV in the separation experiments, while 55.98%, 59.46%, 5.80% were reached respectively when the plate voltage was 26 kV in the simulation. In general, experimental data were similar with numerical simulation. The turning points appeared around 25 kV due to the increasing mismatch in products, which resulted from the reinforced rebound phenomena, namely the charged particle rebound from the electrode plate with a larger reflection velocity, when the plate voltage increased from 18 to 28 kV. It was validated by the numerical simulation results.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 3; 722-731
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on new process for separation of silicon wafers and glass from decommissioned photovoltaic module
Autorzy:
Zhang, Jian wen
Wang, Hai dong
Zhang, Sheng guang
Liang, Han
Guo, Hui
Tao, Si-yao
Powiązania:
https://bibliotekanauki.pl/articles/2175425.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
crystalline silicon photovoltaic modules
decommissioned photovoltaic modules
silicon
solar cell
tempered glass
vibration separation
Opis:
In view of the disadvantages of the existing electrostatic separation process of decommissioned photovoltaic modules, which can only achieve the separation of fine silicon wafers and glass and has high energy consumption, a new process to solve the efficient dry separation of coarse silicon wafers and glass in decommissioned photovoltaic modules is proposed- the vibration separation method. Based on the theoretical analysis of the vibration separation of flaky silicon wafer and polyhedral glass particles, the effects of feed size, feed amount, vibration voltage, vibration frequency, horizontal inclination angle and longitudinal inclination angle on the product indexes of wafer and glass separation were investigated by single factor experiment. The optimal experimental conditions were obtained as follows: feed particle size +0.83mm, feed amount 0.15 t/h, vibration voltage 190 V, vibration frequency 48 Hz, horizontal inclination Angle 8°, longitudinal inclination Angle 3°. Under this optimized condition, the content of metal Si in the obtained silicon wafer product is 84.47%, the recovery rate of is 83.73%, the content of impurity SiO2 is 1.09%, and the content of SiO2 in the obtained glass product is 65.69%, and the recovery rate is 98.95%, the impurity metal Si content is 0.56%. This study provides a research idea for the industrial separation of silicon wafers and glass from decommissioned photovoltaic modules.
Źródło:
Physicochemical Problems of Mineral Processing; 2022, 58, 6; art. no. 151679
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Infrared small-target detection under a complex background based on a local gradient contrast method
Autorzy:
Yang, Linna
Xie, Tao
Liu, Mingxing
Zhang, Mingjiang
Qi, Shuaihui
Yang, Jungang
Powiązania:
https://bibliotekanauki.pl/articles/2201024.pdf
Data publikacji:
2023
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
small target detection
local gradient contrast
visual saliency
infrared image processing
kontrast lokalny
wyróżnienie wizualne
obrazowanie w podczerwieni
Opis:
Small target detection under a complex background has always been a hot and difficult problem in the field of image processing. Due to the factors such as a complex background and a low signal-to-noise ratio, the existing methods cannot robustly detect targets submerged in strong clutter and noise. In this paper, a local gradient contrast method (LGCM) is proposed. Firstly, the optimal scale for each pixel is obtained by calculating a multiscale salient map. Then, a subblockbased local gradient measure is designed; it can suppress strong clutter interference and pixel-sized noise simultaneously. Thirdly, the subblock-based local gradient measure and the salient map are utilized to construct the LGCM. Finally, an adaptive threshold is employed to extract the final detection result. Experimental results on six datasets demonstrate that the proposed method can discard clutters and yield superior results compared with state-of-the-art methods.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2023, 33, 1; 33--43
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pinellia ternata agglutinin produced in Bombyx mori cells exhibits bioactivity
Autorzy:
Xu, Tao
Wang, Bo
Wang, Liya
Zhang, Yaozhou
Lv, Zhengbing
Powiązania:
https://bibliotekanauki.pl/articles/1039738.pdf
Data publikacji:
2012
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
Pinellia ternata agglutinin
silkworm bioreactor
plant lectin
Bombyx mori cells
Opis:
Pinellia ternata agglutinin (PTA) is highly homologous to many other monocot mannose-binding lectins which reportedly possess antitumor activities. Its production in silkworm cells has great application potential because the baculovirus expression system can produce post-translationally modified proteins at low cost. In the current study, the pta gene was cloned and expressed in silkworm cells, and the expressed protein was analyzed using a hemagglutination assay. A preliminary in vitro study on its anti-proliferative activity was performed. The results show that the recombinant PTA with an apparent molecular mass of 29 kDa can hemagglutinate rabbit erythrocytes and this activity can be inhibited by D-mannan at a low concentration. In addition, the recombinant hemagglutinin exhibited a dose-dependent anti-proliferative activity on hepatoma cells. The results of the current study suggest that PTA and other important bioactive proteins could be produced by silkworm bioreactor for biomedicine research and application.
Źródło:
Acta Biochimica Polonica; 2012, 59, 2; 231-236
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Coelacanths from the Middle Triassic Luoping Biota, Yunnan, South China, with the earliest evidence of ovoviviparity
Autorzy:
Wen, W.
Zhang, Q.-Y.
Hu, S.-X.
Benton, M.J.
Zhou, C.-Y.
Tao, X.
Huang, J.-Y.
Chen, Z.-Q.
Powiązania:
https://bibliotekanauki.pl/articles/23008.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
coelacanth
Middle Triassic
Triassic
Yunnan province
South China
China
evidence
ovoviviparity
Anisian
Actinistia
Coelacanthoidei
Latimerioidei
Opis:
The fossil record of coelacanths is patchy, with very few taxa known from the Triassic of Asia. We report here two new genera and species of coelacanths from the Luoping Biota, a recently found site of exceptional fossil preservation from Yunnan, South China. The first new taxon, Luopingcoelacanthus eurylacrimalis, is based on four specimens, which to− gether show most aspects of the anatomy. One specimen shows two small coelacanths inside the ventral portion of the ab− dominal cavity, and these are interpreted as intrauterine embryos, close to birth size, based on comparisons with previ− ously reported embryos of the fossil coelacanths Rhabdoderma and Undina, and the extant genus Latimeria. Our new find extends the evidence for ovoviviparity in coelacanths back from the Late Jurassic to the Middle Triassic. The second new taxon, Yunnancoelacanthus acrotuberculatus, is based on one specimen, and differs from Luopingcoelacanthus in the dentary, lachrymojugal, number of rays of the first dorsal fin, and especially in the ornament on dermal bones and scales. Acladistic analysis shows that the new taxa are closest relatives to the derived clade Latimerioidei. The relatively high di− versity of coelacanths in the Early Triassic, and adaptations of living Latimeria to low−oxygen conditions, suggests that the group may have included ‘disaster taxa’ that benefited from anoxic and dysoxic ocean conditions in the aftermath of the end−Permian mass extinction.
Źródło:
Acta Palaeontologica Polonica; 2013, 58, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł

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