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Tytuł:
Design and Analysis of Ultrasonic Composite Transducer with a Quarter-wave Taper Transition Horn
Autorzy:
Chen, Tao
Li, Hongbo
Wang, Qihan
Ye, Junpeng
Powiązania:
https://bibliotekanauki.pl/articles/1953535.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
equivalent circuit
composite transducer
quarter-wave
prestressed bolt
finite element analysis
Opis:
Based on the electromechanical equivalent circuit theory, equations related to the resonance frequency and the magnifying coefficient of a quarter-wave vibrator and a quarter-wave taper transition horn were deduced, respectively. A series of 3D models of ultrasonic composite transducers with various conical section length was also established. To reveal the influences of the conical section length and the prestressed bolt on the dynamic characteristics (resonance frequency, amplitude, displacement node, and the maximum equivalent stress) of the models and the design accuracy, finite element (FE) analyses were carried out. The results show that the addition of prestressed bolt increases the resonance frequency and causes the displacement node on the center axis to move towards the small cylindrical section. As the conical section length rises, the increment of resonance frequency reduces and tends to a stable value of 360 Hz while the displacement of the node on the center axis becomes lager and gradually approaches 1.5 mm. Furthermore, the amplitude of the output terminal is stable at 16.18 µm under 220 V peak-topeak (77.8 VRMS) sinusoidal potential excitation. After that, a prototype was fabricated and validated experiments were conducted. The experimental results are consistent with that of theory and simulations. It provides theoretical basis for the design and optimization of small-size, large-amplitude, and high-power composite transducers.
Źródło:
Archives of Acoustics; 2020, 45, 4; 687-697
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The development and utilization of bauxite resources in the Guizhou Province and relevant challenges to the ecology and the environment
Rozwój i wykorzystanie zasobów boksytu w prowincji Guizhou oraz istotne wyzwania dla ekologii i środowiska
Autorzy:
Chen, Xiaofu
Li, Xuexian
Wu, Pan
Zha, Xuefang
Liu, Yabin
Wei, Tao
Ran, Wenrui
Powiązania:
https://bibliotekanauki.pl/articles/2173849.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Instytut Gospodarki Surowcami Mineralnymi i Energią PAN
Tematy:
Guizhou Province
bauxite
development of resources
utilization of resources
ecological environment
counter measures
prowincja Guizhou
boksyt
rozwój zasobów
wykorzystanie zasobów
środowisko ekologiczne
środki zaradcze
Opis:
The environmental problems caused by the development and utilization of mineral resources have become important factors affecting ecological security. Guizhou is a Chinese province with relatively developed paleoweathered sedimentary bauxite deposits, abundant resource reserves, and a long history of mining. And, the demand for bauxite in Guizhou is expected to continue to grow. However, long-term or unreasonable resource development has produced a series of prominent environmental problems, such as the occupation and destruction of land resources and heavy metal pollution in soil and water bodies. Based on the existing research results in China and abroad, this paper analyzes the current situation, distribution characteristics, and development and utilization of bauxite resources in Guizhou to explain the corresponding environmental impacts. The results show that because of the many types and high concentrations of associated elements in bauxite and the high alkalinity, heavy metal components, and radioactive elements in red mud, the development and utilization of bauxite resources are associated with higher environmental risk. And more impact of bauxite mining on regional biodiversity, soil, air, surface water, and groundwater need to be evaluated. This paper also proposes coping strategies or countermeasures of environmental governance and control to achieve the green, sustainable and high-quality development of bauxite-related industries for meeting future environmental requirements.
Problemy środowiskowe spowodowane zagospodarowaniem i wykorzystaniem surowców mineralnych stały się ważnymi czynnikami wpływającymi na bezpieczeństwo ekologiczne. Guizhou to chińska prowincja ze względnie rozwiniętymi osadowymi złożami boksytu, bogatymi rezerwami surowców i długą historią wydobycia. Oczekuje się, że popyt na boksyt w Guizhou będzie nadal rósł. Jednak długoterminowy lub nieracjonalny rozwój wykorzystania zasobów spowodował szereg znaczących problemów środowiskowych, takich jak: zajmowanie i niszczenie zasobów ziemi oraz zanieczyszczenie metalami ciężkimi gleby i zbiorników wodnych. W oparciu o istniejące wyniki badań w Chinach i za granicą, w artykule dokonano analizy obecnej sytuacji, charakterystyki dystrybucji oraz rozwoju i wykorzystania zasobów boksytu w Guizhou, w celu wyjaśnienia odpowiedniego wpływu na środowisko. Wyniki pokazują, że ze względu na wiele rodzajów i wysoką koncentrację towarzyszących pierwiastków w boksycie oraz wysoką alkaliczność, składniki metali ciężkich i pierwiastki radioaktywne w czerwonym szlamie, rozwój i wykorzystanie zasobów boksytu wiążą się z wyższym ryzykiem dla środowiska. Ponadto należy ocenić większy wpływ wydobycia boksytu na regionalną bioróżnorodność, glebę, powietrze, wody powierzchniowe i gruntowe. Niniejsza praca proponuje również strategie radzenia sobie lub środki zaradcze zarządzania i kontroli środowiska w celu osiągnięcia ekologicznego, zrównoważonego i wysokiej jakości rozwoju przemysłu związanego z boksytem dla spełnienia przyszłych wymagań środowiskowych.
Źródło:
Gospodarka Surowcami Mineralnymi; 2022, 38, 2; 5--30
0860-0953
Pojawia się w:
Gospodarka Surowcami Mineralnymi
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
C-V2X Communications for the Support of a Green Light Optimized Speed Advisory (GLOSA) Use Case
Autorzy:
Chochliouros, Ioannis P.
Spiliopoulou, Anastasia S.
Kostopoulos, Alexandros
Agapiou, George
Lazaridis, Pavlos
Zaharis, Zaharias
Chen, Tao
Dardamanis, Athanassios
Kourtis, Michail-Alexandros
Agapiou, Marinos
Herzog, Uwe
Ladid, Latif
Powiązania:
https://bibliotekanauki.pl/articles/1839465.pdf
Data publikacji:
2021
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
5G
cellular V2X
cooperative awareness messages
cooperative intersection
cooperative ITS
green light-optimized speed advisory
intelligent transportation systems
traffic efficiency
vehicle-to-everything
Opis:
Rapid expansion of 5G affects a number of sectors, including vehicular communications relying on cooperative intelligent transportation systems (C-ITS). More specifically, in the context of the Internet of Vehicles (IoV), a particular emphasis is placed on modern cellular V2X (C-V2X) technologies aiming to further improve road safety. This work originates from the detailed scope of the ongoing 5G-DRIVE research project promoting cooperation between the EU and China, with the aim of demonstrating IoV services that rely on vehicle-to-infrastructure (V2I) communications. With the C-V2X approach serving as a point of departure, we analyze and describe a specific green light-optimized speed advisory (GLOSA) use case, for which we provide a detailed descriptive framework, a proposed architectural framework for trials, as well as specific KPIs for the joint assessment of trials between the EU and China. We also discuss the context for performance test procedures to be conducted as part of the intended trials. GLOSA provides end-users with short-term information on upcoming traffic light status to optimize traffic flows, help prevent speed limit violations, improve fuel efficiency, and reduce pollution.
Źródło:
Journal of Telecommunications and Information Technology; 2021, 2; 93-106
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Multi-Layer Micro-Perforated Panel Structure Based on Curled Space for Broadband Sound Absorption at Low Frequencies
Autorzy:
Chu, Jiaming
Liang, Xiao
Yang, Zhen
Liang, Haofeng
Chen, Tao
Su, Liang
Zhou, Zhuo
Powiązania:
https://bibliotekanauki.pl/articles/31339792.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
micro-perforated plate
curled space
broadband sound absorption
complex frequency plane method
Opis:
In this paper, we propose a multi-layer micro-perforated panel structure based on a curled space for broadband sound absorption at low frequencies, which increases the number of perforated panel layers in a limited space using a curled space. The absorption coefficients of the structure under plane wave conditions were calculated using the transfer matrix method and the finite element method. It is demonstrated that the multilayer micro-perforated panel structure can ensure high absorption (consistently over 90%) in the frequency range of 400~5000 Hz. The sound absorption mechanism of the multi-layer micro-perforated panel structure is investigated by using the acoustic impedance along with the reflection coefficient of the complex frequency surface. In addition, we also discuss the effects of the micro-perforated panel parameters on the structural sound absorption coefficient. The results show that the proposed multi-layer micro-perforated panel structure provides an excellent solution for sound absorption in a limited space.
Źródło:
Archives of Acoustics; 2023, 48, 4; 529-538
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A novel process for extraction of iron from a refractory red mud
Autorzy:
Ding, Wei
Xiao, Junhui
Peng, Yang
Shen, Siyue
Chen, Tao
Zou, Kai
Wang, Zhen
Powiązania:
https://bibliotekanauki.pl/articles/1450194.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
red mud
sodium sulfate
segregation roasting
magnetic separation
iron recovery
Opis:
Red mud is a kind of solid waste produced during alumina extraction from bauxite. To extraction valuable iron from red mud, the technology of adding sodium sulfate-segregation roasting-magnetic separation to treat red mud was developed. During the paper, the effects of various process parameters on the extraction of iron by segregation roasting-magnetic separation were studied, and the phase transformation behavior and microstructure of iron are explored. Repeated test results showed that magnetic concentrate (mass percent), TFe of 80.29 % and overall iron recovery of 92.08 %was obtained. The X-ray diffraction (XRD) and scanning electron microscopy (SEM) results indicated that after the segregation roasting, the hematite was transformed into a new metal phase consisting mainly of metallic iron and magnetite. The addition of sodium sulfate during the segregation roasting can obviously improve the efficiency of segregation roasting-magnetic separation for iron extraction.
Źródło:
Physicochemical Problems of Mineral Processing; 2020, 56, 6; 125-136
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effective sensor placement based on a VIKOR method considering common cause failure in the presence of epistemic uncertainty
Autorzy:
Duan, Rong-Xing
He, Jie-Jun
Feng, Tao
Huang, Shu-Juan
Chen, Li
Powiązania:
https://bibliotekanauki.pl/articles/1841697.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
dynamic fault tree
epistemic uncertainty
sensor placement
reliability criterion
diagnostic sensor model
Opis:
Owing to expensive cost and restricted structure, limited sensors are allowed to install in modern systems to monitor the working state, which can improve their availability. Therefore, an effective sensor placement method is presented based on a VIKOR algorithm considering common cause failure (CCF) under epistemic uncertainty in this paper. Specifically, a dynamic fault tree (DFT) is developed to build a fault model to simulate dynamic fault behaviors and some reliability indices are calculated using a dynamic evidence network (DEN). Furthermore, a VIKOR method is proposed to choose the possible sensor locations based on these indices. Besides, a sensor model is introduced by using a priority AND gate (PAND) to describe the failure sequence between a sensor and a component. All placement schemes can be enumerated when the number of sensors is given, and the largest system reliability is the best alternative among the placement schemes. Finally, a case study shows that CCF has some influence on sensor placement and cannot be neglected in the reliabilitybased sensor placement.
Źródło:
Eksploatacja i Niezawodność; 2021, 23, 2; 253-262
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Tensile-tensile Fatigue Behavior of Multi-axial Warp-knitted Reinforced Composite
Ocena właściwości mechanicznych i zmęczeniowych kompozytowych dzianin wieloosiowych
Autorzy:
Gao, X.
Tao, N.
Chen, S.
Wang, L.
Wu, W.
Powiązania:
https://bibliotekanauki.pl/articles/232142.pdf
Data publikacji:
2018
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
multi-axial warp-knitted fabric composite
fatigue behavior
S-N curve
equivalent residual strength
kompozytowe dzianiny wieloosiowe
zmęczenie materiału
krzywa S-N
równoważna wytrzymałość resztkowa
Opis:
An experimental study was carried out on the fatigue behaviour of multi-axial warp-knitted fabric composites. Composite samples reinforced with multi-axial warp-knitted fabric/matrix were manufactured by the vacuum-assisted resin transfer moulding method. Tensile-tensile fatigue cycling was carried out at different load levels, and S-N curves, tensile stress-strain curve and stiffness degradation of the multi-axial composite samples were obtained. Finally post-fatigue tensile tests were done at a stress level of 75%, at the stages of 1/3N and 2/3N, and the equivalent residual strength and stiffness degradation were obtained.
Dokonano oceny właściwości mechanicznych i zmęczeniowych kompozytowych dzianin wieloosiowych. Kompozyty wzmocnione dzianiną wieloosiową wytworzono przy zastosowaniu próżniowej metody formowania. Dokonano oceny zmęczenia materiału i właściwości wytrzymałościowych przy różnych poziomach obciążenia. Przedstawiono krzywe S-N, krzywą naprężenie-odkształcenie i degradację sztywności wieloosiowych próbek kompozytowych. Wykonano również testy zmęczenia materiału przy poziomie naprężenia 75%, w etapach 1/3N i 2/3N. Omówiono równoważną wytrzymałość szczątkową i degradację sztywności kompozytowych dzianin wieloosiowych.
Źródło:
Fibres & Textiles in Eastern Europe; 2018, 1 (127); 73-80
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of socio-economic spatial structure of urban agglomeration in China based on spatial gradient and clustering
Autorzy:
He, Li
Tao, Jian’ge
Meng, Ping
Chen, Dan
Yan, Meng
Vasa, László
Powiązania:
https://bibliotekanauki.pl/articles/19233717.pdf
Data publikacji:
2021
Wydawca:
Instytut Badań Gospodarczych
Tematy:
economic and social development
urban agglomeration
Central Plains Urban Agglomeration (CPUA)
clustering
spatial gradient
Opis:
Research background: Previous studies on the economic and social development of urban agglomerations mostly focus on a single primacy comparative analysis and efficiency evaluation. Spatial structure differentiation is an important feature of urban agglomeration. The lack of economic and social analysis on the spatial structure makes it impossible to determine the development positioning of each city in the urban agglomeration, which affects the sustainable economic development ability of these areas. Purpose of the article: The objective of the article is to analyze the spatial development law and experience of urban agglomeration, this study explores the practice of economic and population spatial structure of city areas in China. For this purpose, CPUA and its central city Zhengzhou was taken as an example, the spatial gradient structure of example was analyzed. Methods: Using economic and population data of 32 cities in this region, growth pole theory, and pole-axis theory, the economic and population spatial structure of urban agglomeration, the spatial gradient structure of central cities in urban agglomerations were analyzed with the method of cluster about radiation index. Findings & value added: (1) In the process of the formation of CPUA, the geo-graphical spatial pattern plays a decisive role in economic and social development. This is an experience from developing countries. (2) CPUA presents a gradient development pattern with Zhengzhou as the center, and economic and social development gradually radiates to the metropolitan area, the core development area, and the character development demonstration area. (3) The economic and social gradients of Zhengzhou, the central city, present the hierarchy rules and characteristics which are driven by the Beijing-Guangzhou-Railway axis and the Longhai-Railway axis. (4) The central city of Zhengzhou still presents insufficient primacy in regional development, which shows that Zhengzhou accounts for 6% of the population of the Central Plains Economic Zone and 14% of GDP, and insufficient agglomeration. Different countries at different stages of economic development have different urban agglomeration development models. The conclusions from China provide new decision-making ideas and methods for spatial structure research and development strategy analysis of urban agglomerations.
Źródło:
Oeconomia Copernicana; 2021, 12, 3; 789-819
2083-1277
Pojawia się w:
Oeconomia Copernicana
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Seroepidemiological study of canine Leishmania infantum and Toxoplasma gondii infections in Shanghai, China, and analysis of risk factors
Autorzy:
Jiang, Wei
Wang, Yan
Liu, Yingchun
Li, Tao
Chen, Yongjun
Wang, Shaohui
Han, Xiangan
Wang, Quan
Powiązania:
https://bibliotekanauki.pl/articles/990968.pdf
Data publikacji:
2016
Wydawca:
Instytut Medycyny Wsi
Tematy:
seroprevalence
leishmania infantum
toxoplasma gondii
household dogs
risk factors
Opis:
The aim of this study was to determine the seroprevalence of Leishmania infantum and Toxoplasma gondii among household dogs in Shanghai (the most important industrial and commercial city in China), and to assess the possible risk factors associated with the infection. During 2014–2015, a total of 408 sera were collected from healthy household dogs and tested for L. infantum and T. gondii infection using commercial ELISA kits. The endemic characteristics according to gender, age group and breed were revealed by statistical descriptions and inference. The positive rates of L. infantum infection (24/408, 5.9%) were lower than those of T. gondii infection (37/408, 9.1%), and co-infection with both parasites was detected in seven dogs (7/408, 1.7%). Seropositivity for either parasite was more likely associated with age: the seroprevalence of T. gondii infection ranged from 1.3% (dogs≤1 year) – 18.7% (dogs>6 years), whereas that of L. infantum ranged from 1.3% (dogs≤1 year) – 9.9 % (dogs>6 years). Interestingly, the rates of exposure to both L. infantum and T. gondii were higher in males than in females. Relatively higher exposure rates for L. infantum and T. gondii were also observed in crossbred dogs compared with purebred dogs. However, neither gender nor breed is likely a determining factor for infection with these two parasites (P > 0.05). Identification of the risk factors that underlie these differences may help in the prevention of L. infantum and T. gondii infection in household dogs. To the best of our knowledge, this is the first report of L. infantum and T. gondii infection in household dogs in Shanghai, which shows that these two important parasites are still prevalent in this region. Therefore, it is necessary to take integrated strategies for prevention and control of infection in animals, which could help to reduce human infection in the region.
Źródło:
Annals of Agricultural and Environmental Medicine; 2016, 23, 3
1232-1966
Pojawia się w:
Annals of Agricultural and Environmental Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental study on triboelectrostatic beneficiation of wet fly ash using Microwave Heating
Autorzy:
Li, H.
Chen, Y.
Zhang, X.
Zhao, Y.
Tao, Y.
Li, C.
He, X.
Powiązania:
https://bibliotekanauki.pl/articles/110399.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
wet fly ash
triboelectrostatic beneficiation
microwave heating
efficiency
Opis:
Triboelectrostatic beneficiation, as a physical method, of fly ash cannot only meet the technical requirements of fly ash application but also recycle of an unburned carbon as a useful energy source. The aim of this study was to investigate the feasibility of improving efficiency of triboelectrostatic beneficiation of wet fly ash using microwave heating. The wet fly ash with different moisture contents had an average loss-on-ignition of 12.56%. The fly ash samples were heated in a microwave oven before the experiments. The experimental conditions were electric field voltage of 40 kV and air flux ranging from 12 to 30 m3/h. The influence of the microwave heating on the wet fly ash triboelectrostatic beneficiation was discussed under the conditions of different microwave intensity and irradiation time. The results indicated that the removal rate and recycle rate of the unburned carbon showed a significant increase performance as the wet fly ash was processed by the microwave heating which was attributed to changes of moisture contents and dielectric constants caused by the microwave heating. The feasibility had been verified according to the experimental study on fly ash with different moisture contents. It can be concluded that the microwave heating process was efficiently applied for the wet fly ash triboelectrostatic beneficiation.
Źródło:
Physicochemical Problems of Mineral Processing; 2016, 52, 1; 328-341
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spatiotemporal analysis of air quality and its relationship with meteorological factors in the Yangtze River Delta
Autorzy:
Li, Y.
Chen, Y.
Karimian, H.
Tao, T.
Powiązania:
https://bibliotekanauki.pl/articles/1192096.pdf
Data publikacji:
2020
Wydawca:
Uniwersytet Warmińsko-Mazurski w Olsztynie / Polskie Towarzystwo Magnezologiczne im. Prof. Juliana Aleksandrowicza
Tematy:
YRD
air quality index
meteorological elements
correlation analysis
air pollution
spatial analysis
Opis:
Air quality is closely related to people’s health and life. In addition to being directly affected by social activities and atmospheric emissions, the impacts of meteorological factors are also significant. Based on daily Air Quality Index (AQI) data and various meteorological parameters in the Yangtze River Delta (YRD), this paper summarized the spatiotemporal evolution characteristics of AQI over YRD, and quantitatively analyzed the contribution of different meteorological elements to air quality. We also evaluated different spatial interpolation methods to produce surface distribution of AQI, and noted that the Ordinary Kriging outperformed other methods. The spatial distribution of AQI in YRD showed seasonal and annual variations. However, the days with AQI over 100 (level ii) were mostly observed in winter. Generally, more severe air pollution was observed in the northern part of YRD than in the southern ones, for example the air quality of the Ningbo metropolitan area was the best, while in Hefei it was the worst. It was found that meteorological parameters have spatially varying effects on AQI. For instance, pressure has a significant positive effect on AQI, and others showed negative correlations. We also predicted AQI by exploiting different machine learning-based models. Through model comparison, it was found that the Autoregressive Integrated Moving Average Model – ARIMA (0,1,2) has higher prediction accuracy for AQI than Multiple Linear Regression (MLR). The findings of this research can be used in future forecasting of air pollution, and also in air pollution controlling programs.
Źródło:
Journal of Elementology; 2020, 25, 3; 1059-1075
1644-2296
Pojawia się w:
Journal of Elementology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Harmonic mitigation in 18-pulse rectifier based on zigzag autotransformer by DC side auxiliary circuit
Autorzy:
Liu, Jiongde
Chen, Xiaoqiang
Wang, Ying
Chen, Tao
Powiązania:
https://bibliotekanauki.pl/articles/949860.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
18-pulse rectifier
harmonic suppressing
zigzag autotransformer
Opis:
To improve the power quality of a multi-pulse rectifier, a zigzag 18-pulse uncontrolled rectifier with an auxiliary circuit at the DC side is proposed. When the grid-side currents are sinusoidal waves, the required DC side injection currents to be compensated can be obtained by analyzing the AC-DC side relationship of diode bridge rectifiers. Then the 6 compensation currents generated by an active auxiliary circuit are injected into the DC side to eliminate the grid-side harmonics of the rectifier. The simulation results verifying the correctness of the theoretical analysis show that the proposed rectifier can mitigate the harmonic content, as the total harmonic distortion of the grid-side current is about 1.45%. In addition, the single-phase inverter used in the active auxiliary circuit has the characters of simple circuit structure and easy controllability.
Źródło:
Archives of Electrical Engineering; 2020, 69, 4; 891-905
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of grinding media on the flotation of copper-activated marmatite
Autorzy:
Long, Tao
Chen, Yao
Shi, Juanjuan
Chen, Wei
Zhu, Yangge
Zhang, Chonghui
Bu, Xianzhong
Powiązania:
https://bibliotekanauki.pl/articles/109857.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
grinding media
copper-activated marmatite
flotation separation
surface property
Opis:
How to avoid the shortage of floatability and non-purpose flotation in marmatite flotation is a big problem. This paper innovatively studies how to reduce these two negative phenomena from the perspective of grinding media. The effects of steel and stainless-steel balls on the flotation performance of copper-activated marmatite were investigated mainly through flotation tests, redox potential measurements, ion concentration tests, and XPS and FT-IR spectrum studies. The flotation results showed that the floatability of copper-activated marmatite remarkably decreased by using the steel ball in the grinding process, but it had a mere influence when stainless-steel medium was used. Redox potential measurements showed that the grinding environment of stainless-steel medium could exhibit a higher oxidizing potential than the steel grinding environment. Results from FTIR, XPS, and ion concentration measurements demonstrated that more ferric ions existed on the copper activated marmatite surface in the steel grinding environment than that in the stainless-steel environment. Ferric ions could further hinder the activation effect of copper ions on marmatite and result in decreased marmatite flotation. This research could potentially explain the mechanism of ferric ions in the grinding process, and it can be utilized to improve the flotation performance of marmatite ore through selecting suitable grinding media in ball mill operations.
Źródło:
Physicochemical Problems of Mineral Processing; 2020, 56, 2; 229-237
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on separation of fine-particle ilmenite and mechanism using flocculation flotation with sodium oleate and polyacrylamide
Autorzy:
Peng, Yang
Xiao, Junhui
Deng, Bing
Wang, Zhen
Liu, Nengyun
Yang, Daoguang
Ding, Wei
Chen, Tao
Wu, Qiang
Powiązania:
https://bibliotekanauki.pl/articles/1450088.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
sodium oleate
polyacrylamide
synergistic effect
ilmenite
flocculation flotation
Opis:
In this paper, sodium oleate, polyacrylamide, soluble starch and sodium carboxymethyl cellulose were used as flocculants to study the flocculation and sedimentation behavior of microfine ilmenite. Sedimentation test shows that sodium oleate and polyacrylamide have good flocculation effect on ultrafine ilmenite. The flocculation rate of ilmenite can be further improved by the combination of sodium oleate and polyacrylamide. It was found that both flocculants could generate chemical adsorption with ilmenite surface, and they all react with $Fe^{3+}$ on ilmenite surface. However, sodium oleate reacts with $Fe^{3+}$ to form a water-insoluble iron oleate precipitate which coats the surface of the ilmenite and hinders the action of polyacrylamide and the remaining $Fe^{3+}$. This problem can be avoided by adding polyacrylamide followed by sodium oleate, and the flotation recovery can be increased significantly.
Źródło:
Physicochemical Problems of Mineral Processing; 2020, 56, 1; 161-172
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Empirical Study of the Evolution of Python Questions on Stack Overflow
Autorzy:
Syam, Gopika
Lal, Sangeeta
Chen, Tao
Powiązania:
https://bibliotekanauki.pl/articles/9783959.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
Python programming
Software Development
Stack Overflow
Topic Modelling
Opis:
Background: Python is a popular and easy-to-use programming language. It is constantly expanding, with new features and libraries being introduced daily for a broad range of applications. This dynamic expansion needs a robust support structure for developers to effectively utilise the language. Aim: In this study we conduct an in-depth analysis focusing on several research topics to understand the theme of Python questions and identify the challenges that developers encounter, using the questions posted on Stack Overflow. Method:We perform a quantitative and qualitative analysis of Python questions in Stack Overflow. Topic Modelling is also used to determine the most popular and difficult topics among developers. Results: The findings of this study revealed a recent surge in questions about scientific computing libraries pandas and TensorFlow. Also, we observed that the discussion of Data Structures and Formats is more popular in the Python community, whereas areas such as Installation, Deployment, and IDE are still challenging. Conclusion: This study can direct the research and development community to put more emphasis on tackling the actual issues that Python programmers are facing.
Źródło:
e-Informatica Software Engineering Journal; 2023, 17, 1; 230107
1897-7979
Pojawia się w:
e-Informatica Software Engineering Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 21

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