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Tytuł:
Response of methane emissions to water levels in simulated constructed wetlands
Autorzy:
Li, Yanran
Xu, Qin
Ji, Shuping
Liu, Jian
Powiązania:
https://bibliotekanauki.pl/articles/2171840.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
methane
Pearson correlation
wetland
temperature water
air temperature
metan
korelacja Pearsona
teren podmokły
temperatura wody
temperatura powietrza
Opis:
Wetland is an important natural source of methane (CH4) generated under the actions of methanogens in the anaerobic environment. A greenhouse experiment was conducted to quantify the response of methane emissions to water levels by simulating three water levels (10, 20, and 40 cm) in constructed wetlands and the methane was determined by the static chamber-gas chromatograph technique. Pearson correlation analysis showed that the emissions of CH4 were positively correlated with water temperature and air temperature while they were negatively correlated with air humidity. The water levels simulation experiment showed that the emission of CH4 was the highest when the water level was 20 cm and the CH4 concentrations of the water-air interface had different patterns at various water levels in the daytime. In conclusion, water level and temperature should be considered when accounting for greenhouse gas emissions in constructed wetlands as they both have important influences on CH4 emission.
Źródło:
Environment Protection Engineering; 2022, 48, 3; 5--12
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An adaptive Kalman filter for online monitoring of mine wind speed
Adaptacyjny filtr Kalmana do ciągłego monitorowania prędkości przepływu powietrza kopalnianego
Autorzy:
Huang, De
Liu, Jian
Deng, Lijun
Li, Xuebing
Song, Ying
Powiązania:
https://bibliotekanauki.pl/articles/219283.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
prędkości przepływu powietrza kopalnianego
laserowy system Dopplerowski do rejestracji prędkości (LDV-Laser Doppler Velocimetry)
filtr Kalmana
maksymalizacja wartości oczekiwanej
układ ciągłego monitorowania
Opis:
The underground complicated testing environment and the fan operation instability cause large random errors and outliers of the wind speed signals. The outliers and large random errors result in distortion of mine wind speed monitoring, which possesses safety hazards in mine ventilation system. Application of Kalman filter in velocity monitoring can improve the accuracy of velocity measurement and eliminate the outliers. Adaptive Kalman Filter was built by automatically adjusting process noise covariance and measurement noise covariance depending on the differences between measured and expected speed signals. We analyzed the fluctuation of airflow flow using data of wind speed flow and distribution characteristics of the tunnel obtained by the Laser Doppler Velocimetry system (LDV) studies. A state-space model was built based on the tunnel airflow fluctuations and wind speed signal distribution. The adaptive Kalman Filter was calculated according to the actual measurement data and the Expectation Maximization (EM) algorithm. The adaptive Kalman filter was used to shield fluid pulsation while preserving system-induced fluctuations. Using the Kalman filter to treat offline wind speed signal acquired by LDV, the reliability of Kalman filter wind speed state model and the characteristics of adaptive Kalman Filter were investigated. Result s showed that the adaptive Kalman filter effectively eliminated the outliers and reduced the root-mean-squares error (RMSE), and the adaptive Kalman filter had better performance than the traditional Kalman filter in eliminating outliers and reducing RMSE. Field experiments in online wind speed monitoring were conducted using the optimized adaptive Kalman Filter. Results showed that adaptive Kalman filter treatment could monitor the wind speed with smaller RMSE compared with LVD monitor. The study data demonstrated that the adaptive Kalman filter is reliable and suitable for online signal processing of mine wind speed monitor.
Złożoność środowiska w którym prowadzone są pomiary prędkości powietrza w warunkach ko-palni podziemnych i niestabilność pracy wentylatorów kopalnianych mogą generować znaczne błędy losowe w rejestrowanych przebiegach sygnałów prędkości przepływu oraz powodować pojawianie się wartości oddalonych. Rejestrowane wartości oddalone oraz znaczne błędy losowe powodują wypaczenie przebiegów sygnałów rejestrowanych przez system monitorowania prędkości przepływu powietrza kopalnianego, stwarzając poważne zagrożenie dla bezpieczeństwa pracy i właściwego funkcjonowania systemu wentylacji. Zastosowanie filtru Kalmana w systemie monitorowania prędkości przepływu powietrza kopalnianego poprawia dokładność pomiarów i eliminuje występowanie wartości oddalonych. Adaptacyjny filtr Kalmana opracowano w oparciu o regulację kowariancji sygnału szumu procesowego i szumu pomiarowego w zależności od różnicy pomiędzy zmierzonymi a oczekiwanymi wartościami sygnału prędkości przepływu powietrza. Przeanalizowano wahania prędkości przepływu powietrza na podstawie charakterystyk prędkości przepływu i jej rozkładu otrzymanych z badań prowadzonych przy wykorzystaniu laserowych systemów Dopplerowskich do rejestrowania prędkości LDV (Laser Doppler Velocimetry). Zbudowano model przestrzeni stanu uwzględniający fluktuacje prędkości przepływu powietrza w tunelu oraz rozkład zarejestrowanych sygnałów prędkości przepływu powietrza kopalnianego. Obliczenia adaptacyjnego filtru Kalmana prowadzono w oparciu o bieżące dane pomiarowe, z wykorzystaniem algorytmu maksymalizacji wartości oczekiwanej (EM). Filtr adaptacyjny użyty został do wyrównania pulsacji przepływu powietrza, przy zachowaniu wszelkich zarejestrowanych fluktuacji wywołanych pracą układu. Filtr Kalmana wykorzystany został do obróbki sygnałów prędkości przepływu powietrza uzyskanych z systemu pomiaru prędkości LDV. Zbadano pewność i niezawodność modelu przestrzeni stanu prędkości przepływu powietrza uzyskanego z wykorzystaniem filtru i przeanalizowano charakterystyki adaptacyjnego filtra Kalmana. Wyniki wskazały, że zastosowanie filtru skutecznie eliminuje wartości oddalone i prowadzi do zmniejszenia wartości błędu średniokwadratowego. Wykazano także, że filtra adaptacyjny Kalmana ma wyższą skuteczność od tradycyjnych filtrów Kalmana w zakresie eliminacji wartości oddalonych i redukcji błędu średniokwadratowego. Prowadzono ciągły monitoring prędkości przepływu powietrza kopalnianego w warunkach polowych z wykorzystaniem zoptymalizowanego adaptacyjnego filtru Kalmana. Zarejestrowane wyniki wskazują, że zastosowanie filtra adaptacyjnego do obróbki sygnału prędkości przepływu prowadzi do uzyskania niższych wartości błędu średniokwadratowego niż w systemach monitoringu LVD. Zebrane w trakcie badań wyniki wykazały pewność i skuteczność działania filtra adaptacyjnego przy jego zastosowaniu do ciągłego monitorowania prędkości przepływu powietrza w kopalniach.
Źródło:
Archives of Mining Sciences; 2019, 64, 4; 813-827
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pollution, Happiness and Willingness to Pay Taxes:The Value Effect of Public Environmental Policies
Zanieczyszczenie, szczęście i chęć płacenia podatków: efekt wartości w ramach publicznych polityk ekologicznych
Autorzy:
Liu, Nannan
Liu, Rong
Huang, Jian
Chen, Lingshuang
Powiązania:
https://bibliotekanauki.pl/articles/371270.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Komitet Człowiek i Środowisko PAN
Tematy:
environmental pollution
sense of happiness
willingness to pay taxes
public policy
zanieczyszczenia środowiska
poczucie szczęścia
podatki oparte na gotowości do zapłaty
polityka publiczna
Opis:
As China’s economic development pattern is marked by an excessive consumption of fossil fuels, environmental pollution problems in China are getting increasingly serious and threatening residents’ fundamental demands for a high quality of life. It has become a handicap to sustainable economic development and social well-being. In this paper, the happiness index method were used, and models depicting the relationship between residents’ sense of happiness and environmental pollution factors and between the willingness to pay taxes and environmental pollution factors have been established. The results show that environmental pollution, especially air pollution, significantly affects the residents’ sense of happiness. To improve residential environment quality and reduce pollution, residents are willing to pay the relevant taxes. If pollution control is considered a public policy, there exists a substantive weight of government between residents’ income and environmental quality. This will influence the choice of environmental public policy.
Rozwój ekonomiczny Chin powiązany jest z nadmiernym zużywaniem paliw kopalnych, a zanieczyszczenia środowiska osiągają poziom, który stanowi zagrożenie dla oczekiwanego przez obywateli wysokiego poziomu życia. Stało się to przeszkodą dla zrównoważonego rozwoju gospodarczego i dobrobytu społecznego. W niniejszym opracowaniu wykorzystano metodę wskaźnika szczęścia. Opracowano modele obrazujące związek między poczuciem szczęścia mieszkańców a zanieczyszczeniami środowiska oraz między chęcią płacenia podatków a czynnikami zanieczyszczenia środowiska. Wyniki pokazują, że zanieczyszczenie środowiska, w szczególności zanieczyszczenie powietrza, znacząco wpływa na poczucie szczęścia mieszkańców. Aby poprawić jakość środowiska mieszkańców i zmniejszyć zanieczyszczenie, obywatele są skłonni zapłacić odpowiednie podatki. Jeżeli kontrola zanieczyszczeń jest uważana za politykę publiczną, rząd odgrywa istotną rolę w kształtowaniu relacji między dochodami mieszkańców a jakością środowiska. Wpłynie to bowiem na wybór polityki publicznej dotyczącej środowiska.
Źródło:
Problemy Ekorozwoju; 2018, 13, 1; 75-86
1895-6912
Pojawia się w:
Problemy Ekorozwoju
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pseudo-static test of steel-glulam composite beam-to-column exterior joints
Autorzy:
Duan, Shaowei
Liu, Xinglong
Yuan, Jian
Wang, Zhifeng
Powiązania:
https://bibliotekanauki.pl/articles/1853633.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
połączenie belka-słup
połączenie zewnętrzne
belka stalowa klejona
belka kompozytowa
test pseudostatyczny
forma przekroju
rozpraszanie energii
nośność
beam to column joint
exterior joint
steel-glulam beam
composite beam
pseudo-static test
cross-section form
energy dissipation
capacity
Opis:
Steel-glulam structure is a new type of composite structure,glulam have lateral support effect on steel plate, that can prevent premature buckling of steel plate and improve the stability of steel structure. In order to study the influence of column’s cross-section form on the seismic performance of steel-glulam composite beam-to-column exterior joint, the column’s cross-section form was taken as the basic variable (glulam rectangular section , H-beam section and H-beam-glulam rectangular section were used respectively). The pseudo-static tests of three composite beam-to-column joints were carried out to observe the different failure modes, and obtain the mechanical performance indexes. The experiment results demonstrated that: The energy dissipation capacity of beam-to-column exterior joint composed of glulam column was the worst, the ultimate bearing capacity and stiffness were the lowest. The ultimate bearing capacity of the exterior joints formed by the H-beam column and the H-beam-glulam composite column were both high, and their ductility coefficients were similar, while the former had better energy dissipation capacity.
Źródło:
Archives of Civil Engineering; 2021, 67, 1; 147-161
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of particle size on flotation separation of ilmenite, olivine, and pyroxene
Autorzy:
Yang, Yaohui
Xu, Longhua
Liu, Shujun
Deng, Jian
Powiązania:
https://bibliotekanauki.pl/articles/1447002.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
olivine pyroxene
ilmenite
fine particles
narrow size
flotation separation
Opis:
The rock type in Panxi area is changing from gabbro type to olivine pyroxene type, which makes it difficult for enterprises to obtain better beneficiation indexes at present. In order to solve this problem, we use a variety of modern test techniques, such as zeta potential measurements, Fourier-transform infrared (FTIR) spectroscopy, adsorption amount measurements, and mineral-reagent interaction energy simulation to analyze the influence of particle size on mineral flotation behavior and the interaction of fine-grained minerals in this paper. The experiments results indicate that the presence of fine-grained (-19 um) mineral particles is deleterious to the flotation of ilmenite, the ilmenite recovery decreases as the microfine grade content of pyroxene and olivine increases, distribution of narrow size minerals is beneficial to the minerals flotation performance, and the order of sodium oleate (NaOL) adsorption strength on different ilmenite crystal planes is (1011) > (0001). The research results of this paper deepen the understanding of the olivine type ilmenite resources in Panxi area, enrich the theoretical system of flotation separation of refractory ilmenite, and provide theoretical support for the key technical problems of flotation separation of ilmenite in Panxi area.
Źródło:
Physicochemical Problems of Mineral Processing; 2021, 57, 5; 106-117
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Graphs Whose Aα-Spectral Radius Does Not Exceed 2
Autorzy:
Wang, Jian Feng
Wang, Jing
Liu, Xiaogang
Belardo, Francesco
Powiązania:
https://bibliotekanauki.pl/articles/31566069.pdf
Data publikacji:
2020-05-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
Aα -matrix
Smith graphs
limit point
spectral radius
index
Opis:
Let A(G) and D(G) be the adjacency matrix and the degree matrix of a graph G, respectively. For any real α ∈ [0, 1], we consider Aα(G) = αD(G) + (1 − α)A(G) as a graph matrix, whose largest eigenvalue is called the Aα-spectral radius of G. We first show that the smallest limit point for the Aα-spectral radius of graphs is 2, and then we characterize the connected graphs whose Aα-spectral radius is at most 2. Finally, we show that all such graphs, with four exceptions, are determined by their Aα-spectra.
Źródło:
Discussiones Mathematicae Graph Theory; 2020, 40, 2; 677-690
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fabric Composition and Wearability Analysis of Zhuanghua
Autorzy:
Sun, Ying
Liu, Zheng
Silberman, Jeffrey
Hou, Jue
Dai, Jian
Powiązania:
https://bibliotekanauki.pl/articles/2171973.pdf
Data publikacji:
2022
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
Zhuanghua
Zhuanghua satin
Zhuangzhi technique
wearability
Yun brocade
Opis:
Zhuanghua is a representative variety of Nanjing Yun brocade, symbolising the highest achievement of ancient Chinese textile technology. It has been widely used as a clothing fabric since its appearance. This paper firstly explored the characteristics of weaving materials, fabric weaves, and fabric weaving of Zhuanghua based on a literature review, manufactory visiting, and a market survey. To preserve the textile application, the permeability, shape preservation property, and appearance preservation property of fabric were tested for wearability. Specifically, six pieces of Zhuanghua satin were selected as the primary samples, along with six pieces of customised plain satin as the matching samples. Influenced by the Zhuangzhi technique, the Zhuanghua satin presented the following features. The thickness and air permeability of the Zhuanghua satin varied between patterned and non-patterned parts. The Zhuanghua satin in the weft direction showed higher tensile strength, stronger stiffness, and weak crease recovery ability. The average weft elongation at break of Zhuanghua satin increased by 25% and the weft flexural rigidity by 3-8 times, while the average weft crease recovery angle decreased by nearly 30°. The performance of anti-fuzzing and anti-pilling was improved, and the grades increased by 1 and 2, respectively. The study is conducive to a more scientific understanding and development of Yun brocade.
Źródło:
Fibres & Textiles in Eastern Europe; 2022, 4 (151); 9--20
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparisons Between 2D and 3D MPFEM Simulations in Modeling Uniaxial High Velocity Compaction Behaviors of Ti-6Al-4V Powder
Autorzy:
Zhou, Jian
Xu, Hongkun
Zhu, Chenyu
Wang, Bin
Liu, Kun
Powiązania:
https://bibliotekanauki.pl/articles/2048874.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
multi-particle finite element method
Ti-6Al-4V
powder compaction
relative green density
impact energy per unit mass
Opis:
Multi-particle finite element method (MPFEM) simulation has been proven an efficient approach to study the densification behaviors during powder compaction. However, comprehensive comparisons between 2D and 3D MPFEM models should be made, in order to clarify which dimensional model produces more accurate prediction on the densification behaviors. In this paper, uniaxial high velocity compaction experiments using Ti-6Al-4V powder were performed under different impact energy per unit mass notated as Em. Both 2D and 3D MPFEM simulations on the powder compaction process were implemented under displacement control mode, in order to distinguish the differences. First, the experimental final green density of the compacts increased from 0.839 to 0.951 when Em was increased from 73.5 J/g to 171.5 J/g. Then detailed comparisons between two models were made with respect to the typical densification behaviors, such as the density-strain and density-pressure relations. It was revealed that densification of 2D MPFEM model could be relatively easier than 3D model for our case. Finally, validated by the experimental results, 3D MPFEM model generated more realistic predictions than 2D model, in terms of the final green density’s dependence on both the true strain and Em. The reasons were briefly explained by the discrepancies in both the particles’ degrees of freedom and the initial packing density.
Źródło:
Archives of Metallurgy and Materials; 2022, 67, 1; 57-65
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on low frequency ripple suppression technology of inverter based on model prediction
Autorzy:
Liu, Haiyang
Chen, Yiwen
Luo, Sixu
Jiang, Jiahui
Jian, Haojun
Powiązania:
https://bibliotekanauki.pl/articles/24202730.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
boost type
low frequency ripple suppression
model predictive control
single stage inverter
Opis:
The low frequency ripple of the input side current of the single-phase inverter will reduce the efficiency of the power generation system and affect the overall performance of the system. Aiming at this problem, this paper proposes a two-modal modulation method and its MPC multi-loop composite control strategy on the circuit topology of a single-stage boost inverter with a buffer unit. The control strategy achieves the balance of active power on both sides of AC and DC by controlling the stable average value of the buffer capacitor voltage, and provides a current reference for inductance current of the DC input side. At the same time, the MPC controller uses the minimum inductor current error as the cost function to control inductor current to track its reference to achieve low frequency ripple suppression of the input current. In principle, it is expounded that the inverter using the proposed control strategy has better low frequency ripple suppression effect than the multi-loop PI control strategy, and the conclusion is proved by the simulation data. Finally, an experimental device of a single-stage boost inverter using MPC multi-loop composite control strategy is designed and fabricated, and the experimental results show that the proposed research scheme has good low frequency ripple suppression effect and strong adaptability to different types of loads.
Źródło:
Archives of Electrical Engineering; 2023, 72, 2; 443--460
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of polyacrylamide on the process of removing impurities in the rare earth leachate
Autorzy:
Wu, Xiaoyan
Zhou, Fang
Liu, Chufan
Feng, Jian
Zhang, Zhenyue
Chi, Ruan
Powiązania:
https://bibliotekanauki.pl/articles/1448504.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
polyacrylamide
rare earth leachate
impurity removal
flocs
Opis:
The impurity removal process of the rare earth (RE) leachate is usually accompanied by the formation of flocs, and a certain amount of polyacrylamide flocculant needs to be added in this process. However, few studies have investigated the effect of the flocculant on the impurity removal process. Therefore, this paper compares the influence on the process of removing impurities with or without the adding of polyacrylamide (PAM). The results showed that the addition of PAM had little effect on the removal rate of impurities, but it was conducive to the recovery of RE. When ammonium bicarbonate was firstly adopted to regulate the solution pH to 5.0, and then sodium sulfide was used to adjust the pH to 5.2, and 0.5 mL/100 mL of PAM was added to the leachate, 96% $Al^{3+}$ and 98% $Zn{2+}$ were removed from the leachate, while 95% RE was maintained. In addition, PAM could accelerate the settlement of flocs and then shorten the production cycle. The increase in RE recovery rate may be due to the addition of PAM to shorten the settling time of the flocs, thereby reducing the RE ions adsorbed during the flocculation process and increasing the recovery rate of the RE.
Źródło:
Physicochemical Problems of Mineral Processing; 2021, 57, 1; 182-191
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
CFD simulation on wind turbine blades with leading edge erosion
Autorzy:
Wang, Yan
Wang, Liang
Duan, Chenglin
Zheng, Jian
Liu, Zhe
Ma, Gaosheng
Powiązania:
https://bibliotekanauki.pl/articles/2055055.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
wind turbine
leading edge erosion
flow field structure
aerodynamic performance
Opis:
Deep understanding on the impacts of leading edge erosion on the performance and flow characteristics of wind turbines is significant for the blade design and wind farms manage- ment. Pitting erosion and three levels of delamination are considered in the present study. The results show that the degrees of leading edge erosion have great influence on the flow separation, tangential force coefficient, normal force coefficient as well as the power output of the wind turbine. Leading edge erosion has the greatest impact on aerodynamics of the wind turbine at 15m/s, where the maximum loss in the power output can reach up to 73.26%.
Źródło:
Journal of Theoretical and Applied Mechanics; 2021, 59, 4; 579--593
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Direct reuse of rare earth oxalate precipitation mother liquor for rare earth leaching
Autorzy:
Wu, Xiaoyan
Zhou, Fang
Feng, Jian
Liu, Xueme
Zhang, Zhenyue
Chi, Ruan
Powiązania:
https://bibliotekanauki.pl/articles/109869.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
weathered crust elution-deposited rare earth ore
oxalic acid
precipitation
mother liquor
Opis:
In the recovery process of rare earth (RE) from the weathered crust elution-deposited rare earth ore, ammonium sulfate is used as the leaching liquor to leach RE, and then the leachate containing RE3+ can be precipitated by oxalic acid and the RE oxalate precipitation mother liquor is reused for RE leaching process after removing the residual oxalic acid by precipitation with calcium hydroxide. However, the reuse process of precipitation mother liquor cannot proceed in the strong acid and alkali restricted areas and the discharge of mother liquor which contains a large amount of ammonium salt will cause ammonia-nitrogen waste and pollution. In order to realize the reuse of the precipitation mother liquor in this area, the direct reuse of RE oxalate precipitation mother liquor for RE leaching was investigated in this study. The RE oxalate precipitation process and the RE leaching process with oxalic acid were studied. The results showed that the residual oxalic acid concentration in the mother liquor can be controlled lower than 0.8 g/dm3 at pH 2-3 when the RE concentration in the leachate was 0.1- 1.5 g/dm3 and the RE precipitation rate reached to 94%. In addition, RE leaching efficiency was up to 90% while the oxalic acid concentration in the prepared mother liquor was 0.2-0.8 g/dm3, pH 2-3. Therefore, the precipitation mother liquor with oxalic acid concentration less than 0.8 g/dm3 could be directly reused for RE leaching. However, considering the different performance of RE ores, the recommended oxalic acid concentration in the direct used precipitation mother liquor was lower than 0.6 g/dm3.
Źródło:
Physicochemical Problems of Mineral Processing; 2019, 55, 3; 760-769
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of bearing capacity of multi-span spandrel-braced stone arch bridge based on static load test
Autorzy:
Gao, Hongshuai
Duan, Hourui
Sun, Yue
Jian, Jiashuo
Zhang, Jingyuan
Liu, Hongbo
Powiązania:
https://bibliotekanauki.pl/articles/2174067.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Opis:
Stone arch bridge is an important type in the early bridge construction process because of its beautiful shape, material saving and economic rationality. However, stone material will deteriorate after long-term operation, which results in a decrease in strength and bearing capacity of stone arch bridge. The vehicle load is increasing at the same time. Therefore, accurate evaluation of bearing capacity of stone arch bridge is essential to ensure safety. In this article, a three-span open-spandrel stone arch bridge was taken as research object. Firstly, the bridge damages were investigated and analyzed in detail, and bridge service state was evaluated. Then, based on the evaluation results of disease damages and considering stone material deterioration, a refined finite element model of stone arch bridge was established to analyze bending moment, axial force, strain and deformation. Finally, static load test was carried out to test vertical deformation and stress of arch ring, horizontal displacement of pier, settlement of foundation and development of cracks. The results show that static load test is the most accurate method for evaluating bearing capacity of stone arch bridge. The evaluation accuracy of finite element model based on material correction is in the middle, and the evaluation accuracy of disease damage assessment is the worst. In practical work, bearing capacity of stone arch bridge can be evaluated by combining the three methods with high accuracy and comprehensive results.
Źródło:
Archives of Civil Engineering; 2022, 68, 4; 633--651
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fault mode analysis and reliability optimization design of a mechanical interface based on cylindrical cam mechanisms
Autorzy:
Li, Jian-Hao
Liu, Zhi-Jie
Wang, Da-Peng
Tian, Yun
Zhao, Yu-Chong
Powiązania:
https://bibliotekanauki.pl/articles/1841922.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
mechanical interface
fault mode analysis
Monte Carlo simulation
reliability design
cylindrical cam mechanism
Opis:
The mechanical interface has the characteristics of low shock and vibration, and is emphasized in the aerospace and ocean engineering fields. In this paper, a mechanical interface based on coupled cylindrical cam mechanisms is designed. It can achieve the expected functions, but there exist faults in some times. The fault modes and causes of the interface are firstly analyzed. Then a design approach based on Monte Carlo simulation is presented for analyzing and optimizing its reliability. According to the fault modes, the performance functions of the interface are established for obtaining the optimal scheme. A case is given to illustrate the proposed method. The simulation results and the prototype experiments prove that the optimization scheme effectively improves the reliability of the interface, and has better performance than the original one.
Źródło:
Eksploatacja i Niezawodność; 2020, 22, 4; 715-723
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adsorption of lanthanum(III) and yttrium(III) on kaolinite: kinetics and adsorption isotherms
Autorzy:
Zhou, Fang
Feng, Jian
Xie, Xiong
Wu, Baihong
Liu, Qi
Wu, Xiaoyan
Chi, Ruan
Powiązania:
https://bibliotekanauki.pl/articles/109951.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
adsorption
kaolinite
rare earth
kinetics
Opis:
Experimental investigations were carried out using kaolinite to adsorb two rare earth ions, lanthanum ion (La3+) and yttrium ion (Y3+), which will provide some useful information and new insights on the mineralization process and fractionation phenomenon of weathered crust elution-deposited rare earth ores. The results showed that the equilibrium adsorption capacity of Y3+ is greater than La3+ under the same experimental conditions. The adsorption of rare earth ions presents strongly temperature dependent indicating an endothermic adsorption process. The pseudo-first-order kinetic model and the pseudo-second-order kinetic model were applied to discuss the adsorption kinetics. It was found that the adsorption rate of rare earth follows the pseudo-second-order kinetic model among the adsorption temperature range. Furthermore, the adsorption process of rare earth ions on kaolinite followed the Langmuir isotherm model confirmed by the correlation of experimental equilibrium data to standard isotherm model, Langmuir and Freundlich isotherms. The activation energies for the adsorption of La3+ and Y3+ on kaolinite are 28.1903 kJ/mol and 25.4190 kJ/mol, respectively. All kaolinite before and after adsorption were characterized by XRD and SEM-EDX to understand the adsorption mechanism. The obtained results suggested that the adsorption of La3+ and Y3+ on kaolinite is an endothermic and chemisorption process.
Źródło:
Physicochemical Problems of Mineral Processing; 2019, 55, 4; 928-939
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 23

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