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Wyszukujesz frazę "Zhao, Wei" wg kryterium: Autor


Tytuł:
A source discrimination method of mine water-inrush based on 3D spatial interpolation of rare classes
Analiza dyskryminacyjna źródeł wycieków wody do kopalni na podstawie trójwymiarowej interpolacji danych o zdarzeniach rzadkich
Autorzy:
Jiang, Qiong
Zhao, Weidong
Zheng, Yong
Wei, Jiajia
Wei, Chao
Powiązania:
https://bibliotekanauki.pl/articles/219790.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
analiza dyskryminacyjna źródeł wycieków
wyciek wód
jakość wód
kryterium Bayesowskie
kategoria zdarzeń rzadkich
source discrimination
water inrush
water quality
Bayesian classifier
rare class
Opis:
When the distribution of water quality samples is roughly balanced, the Bayesian criterion model of water-inrush source generally can obtain relatively accurate results of water-inrush source identification. However, it is often difficult to achieve desired classification results when training samples are imbalanced. Sample imbalance is common in the source identification of mine water-inrush. Therefore, we propose a three-dimensional (3D) spatial resampling method based on rare water quality samples, which achieves the balance of water quality samples. Based on the virtual water sample points distributed by the 3D grid, the method uses the 3D Inverse Distance Weighting (IDW) method to interpolate the groundwater ion concentration of the virtual water samples to achieve oversampling of rare water samples. Case study in Gubei Coal Mine shows that the method improves overall discriminant accuracy of the Bayesian criterion model by 5.26%, from 85.26% to 90.69%. In particular, the discriminative precision of the rare class is improved from 0% to 83.33%, which indicates that the method can improve the discriminant accuracy of the rare class to large extent. In addition, this method increases the Kappa coefficient of the model by 19.92%, from 52.26% to 72.19%, increasing the degree of consistency from “general” to “significant”. Our research is of significance to enriching and improving the theory of prevention and treatment of mine water damage.
W przypadku zrównoważonych danych o jakościowym rozkładzie próbek, zastosowanie kryterium Bayesowskiego do modelowania źródeł wycieków daje stosunkowo dokładne wyniki w analizie dyskryminacyjnej źródeł wycieków wody kopalnianej. Jednakże w przypadku niezrównoważonych danych, pożądane efekty kategoryzacji są niezmiernie trudne do uzyskania. Dane o składzie próbek są w znacznej mierze niezrównoważone, i jest to powszechny problem napotykany przy identyfikacji źródeł wycieków. W obecnej pracy zaproponowano więc trójwymiarową (3D) metodę powtórnego próbkowania z wykorzy-staniem próbek wód z kategorii zdarzeń rzadkich, tak by uzyskać zrównoważony zbiór danych. W oparciu o wirtualne punkty na trójwymiarowej siatce, wykorzystano trójwymiarową metodęśredniej ważonej odległością (Inverse Distance Weighing – IDW) do interpolacji stężenia jonów w wodach gruntowych w wirtualnych próbkach wody, w celu nadpróbkowania dla kategorii zdarzeń rzadkich. Studium przypadku kopalni węgla Gubei pokazuje, że metoda poprawia dokładność dopasowania modelu w oparciu o kryterium Bayesowskie o 5.25% (z 85.26% na 90.96 %). W szczególności, dokładność rozróżniania i dyskryminacji próbek należących do kategorii zdarzeń rzadkich wzrasta od 0% do 83.33%, co oznacza bardzo znaczna poprawę. Ponadto, wartość współczynnika Kappa wzrasta o 19.92%, od 52.26 % do 72.19%, tym samym podnosząc poziom zgodności metody z poziomu ogólnego na „znaczący”. Prowadzone przez nas badania mają poważne znaczenie z punktu widzenia udoskonalenia teorii leżących u podstaw metod i technik zapobiegania i kontroli wycieków wód kopalnianych.
Źródło:
Archives of Mining Sciences; 2019, 64, 2; 321-333
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Acoustic emission characteristics of deep granite under triaxial cylic loading and unloading
Autorzy:
Pei, Feng
Zhang, Yue-Zheng
Zhao, Ji-Wei
Geng, Jing-Ming
Powiązania:
https://bibliotekanauki.pl/articles/1402362.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Wydział Geoinżynierii, Górnictwa i Geologii. Instytut Górnictwa
Tematy:
deep granite
acoustic emission
frequency spectrum
precursory feature recognition
Opis:
In order to obtain the damage and AE characteristics of deep granite, TAW-2000 electrohydraulic servo rigid testing equipment and PCI-2 acoustic emission acquisition system were used to clarify the relationship between AE characteristics and stress level under conventional triaxial and cyclic loading and unloading. The results show that: AE characteristic parameters such as counts and energy under different confining pressures have good consistency in reflecting cracks growth process, which correspond to the stress level of rock sample; Before the critical failure, the AE amplitude increases significantly and extremely high peak frequency and extremely low peak frequency began to appear; The phenomenon that peak frequency band number increases significantly can be used as the precursor of rock failure; The change trend of characteristic parameters, amplitude and peak frequency band were related to the stress level of rock, and the loading path has little influence on it, which verified the effectiveness of AE precursory feature recognition; FR value decreases continuously with the increase of cyclic stress level and overall trend is downward, which indicated that AE memory gradually decreases as the stress level increases; From the perspective of damage mechanics, the AE characteristics of rock before failure are explained reasonably by the development of damage rate.
Źródło:
Mining Science; 2020, 27; 209-225
2300-9586
2353-5423
Pojawia się w:
Mining Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An approach to multiple attribute decision making with combined weight information in interval-valued intuitionistic fuzzy environment
Autorzy:
Wei, G.
Zhao, X.
Powiązania:
https://bibliotekanauki.pl/articles/206267.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
multiple attribute decision making
interval-valued intuitionistic fuzzy number
interval-valued intuitionistic fuzzy weighted averaging (IIFWA)
weight information
Opis:
With respect to multiple attribute decision making problems with interval-valued intuitionistic fuzzy information, some operational laws of interval-valued intuitionistic fuzzy numbers, score function and accuracy function of interval-valued intuitionistic fuzzy numbers are introduced. A combined optimization model based on the deviation method, by which the attribute weights can be determined, is established. For special situations, in which information about attribute weights is completely unknown, we establish another combined optimization model. By solving this model, we get a simple and exact formula, which can be used to determine the attribute weights. We utilize the interval-valued intuitionistic fuzzy weighted averaging (IIFWA) operator to aggregate the intuitionistic fuzzy information corresponding to each alternative, and then rank the alternatives and select the most desirable one(s) according to the score and accuracy functions. Finally, an illustrative example is given to verify the developed approach and to demonstrate its practicality and effectiveness.
Źródło:
Control and Cybernetics; 2012, 41, 1; 97-112
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An improved feature extraction method for rolling bearing fault diagnosis based on MEMD and PE
Autorzy:
Zhang, H.
Zhao, L.
Liu, Q.
Luo, J.
Wei, Q.
Zhou, Z.
Qu, Y.
Powiązania:
https://bibliotekanauki.pl/articles/259770.pdf
Data publikacji:
2018
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
improved feature extraction method
rolling bearing fault diagnosis
MEMD
PE
Opis:
The health condition of rolling bearing can directly influence to the efficiency and lifecycle of rotating machinery, thus monitoring and diagnosing the faults of rolling bearing is of great importance. Unfortunately, vibration signals of rolling bearing are usually overwhelmed by external noise, so the fault frequencies of rolling bearing cannot be readily obtained. In this paper, an improved feature extraction method called IMFs_PE, which combines the multivariate empirical mode decomposition with the permutation entropy, is proposed to extract fault frequencies from the noisy bearing vibration signals. First, the raw bearing vibration signals are filtered by an optimal band-pass filter determined by SK to remove the irrelative noise which is not in the same frequency band of fault frequencies. Then the filtered signals are processed by the IMFs_PE to get rid of the relative noise which is in the same frequency band of fault frequencies. Finally, a frequency domain condition indicator FFR(Fault Frequency Ratio), which measures the magnitude of fault frequencies in frequency domain, is calculated to compare the effectiveness of the feature extraction methods. The feature extraction method proposed in this paper has advantages of removing both irrelative noise and relative noise over other feature extraction methods. The effectiveness of the proposed method is validated by simulated and experimental bearing signals. And the results are shown that the proposed method outperforms other state of the art algorithms with regards to fault feature extraction of rolling bearing.
Źródło:
Polish Maritime Research; 2018, S 2; 98-106
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of abnormal vibrations of crude oil efflux pumps using Ansys
Autorzy:
Wang, Tianqi
Xie, Lei
Yu, Hongsheng
Wei, Xiuliang
Dong, Pengmin
Zhao, Tianyi
Powiązania:
https://bibliotekanauki.pl/articles/2200858.pdf
Data publikacji:
2023
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
abnormal vibrations
internal flow field
Ansys
Opis:
In this study, abnormal vibrations of 1 pump fluid in a crude oil efflux station in the Changqing Oilfield was investigated. Kinetic simulation was applied to flow fields in the crude oil efflux pump using Ansys to determine trends of the impeller static pressure, speed, total pressure, wall pressure of the impeller, outlet pressure and pressure on the pump shell and to identify the reasons behind the abnormal vibrations. The results indicated that the axial vibration amplitude of the pump could be reduced from 1.3mm down to 0.68mm if the operation parameters of the external control oil pump were set as 2500-2550r/min and 325-335m3/h, respectively.
Źródło:
Journal of Theoretical and Applied Mechanics; 2023, 61, 1; 23--36
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of Clothing Image Classification Models: A Comparison Study between Traditional Machine Learning and Deep Learning Models
Autorzy:
Xu, Jun
Wei, Yumeng
Wang, Aichun
Zhao, Heng
Lefloch, Damien
Powiązania:
https://bibliotekanauki.pl/articles/2200761.pdf
Data publikacji:
2022
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
e-commerce
clothing image classification
traditional machine learning
CNN
HOG
SVM
small VGG network
Opis:
Clothing image in the e-commerce industry plays an important role in providing customers with information. This paper divides clothing images into two groups: pure clothing images and dressed clothing images. Targeting small and medium-sized clothing companies or merchants, it compares traditional machine learning and deep learning models to determine suitable models for each group. For pure clothing images, the HOG+SVM algorithm with the Gaussian kernel function obtains the highest classification accuracy of 91.32% as compared to the Small VGG network. For dressed clothing images, the CNN model obtains a higher accuracy than the HOG+SVM algorithm, with the highest accuracy rate of 69.78% for the Small VGG network. Therefore, for end-users with only ordinary computing processors, it is recommended to apply the traditional machine learning algorithm HOG+SVM to classify pure clothing images. The classification of dressed clothing images is performed using a more efficient and less computationally intensive lightweight model, such as the Small VGG network.
Źródło:
Fibres & Textiles in Eastern Europe; 2022, 5 (151); 66--78
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Assessing the effectiveness of training programme on the competency of medical staffs in public health emergency
Autorzy:
Zhao, Yuhan
Wei, Chenming
Ni, Liezong
Zhang, Jinghua
Yin, Xunbao
Sun, Hongwei
Powiązania:
https://bibliotekanauki.pl/articles/2188853.pdf
Data publikacji:
2023
Wydawca:
Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:
competency
system professional training
public health emergency
self-designed questionnaire
medical staffs
training
Opis:
Background The competencies of medical staff in the public health emergency system and evaluated the effects of system-based professional training were investigated. Material and Methods A competency model for individuals in a public health emergency management system was developed, which contained 33 items with 5 domains. A competency-based intervention was performed. A total of 68 participants from 4 health emergency teams in Xinjiang, China were recruited and randomly divided into 2 groups: the intervention (N = 38) and control groups (N = 30). Participants in the intervention group received competency-based training, while those in the control group received no training. All participants responded to the COVID-19 activities. The competencies of medical staff in the 5 domains were then analyzed in the pre-intervention, post-first training, and post-COVID-19 intervention using a self-designed questionnaire. Results Participants’ competencies were at the middle level at baseline. After the first training, competencies in the 5 domains significantly improved in the intervention group; in the control group, there was a significant increase in professional quality compared in the pre-training. After the response to COVID-19, the mean scores of competencies in the 5 domains significantly increased in both the intervention and control groups compared with those in the post-first training. Psychological resilience scores were higher in the intervention group than in the control group, whereas no significant differences in competencies were found in other domains. Conclusions Competency-based interventions provided practice and showed a positive effect on improving the competencies of medical staff in public health teams. Med Pr. 2023;74(1)
Źródło:
Medycyna Pracy; 2023, 74, 1; 19-26
0465-5893
2353-1339
Pojawia się w:
Medycyna Pracy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bulldoze and rebuild: Modifying cratonic lithosphere via removal and replacement induced by continental subduction
Autorzy:
Meng, Lingtong
Chu, Yang
Lin, Wei
Mitchell, Ross N.
Zhao, Liang
Powiązania:
https://bibliotekanauki.pl/articles/24202141.pdf
Data publikacji:
2023
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
lithosphere
China
Opis:
Establishing the mechanisms for craton modification is critical for understanding cratonic stability and architecture. Both plate tectonics and mantle plumes can cause weakening, mechanical decoupling, and even lithospheric removal. But craton modification  – craton destruction accompanied or followed by craton rejuvenation  – has received less attention. It is well-known that oceanic subduction dominantly destroys cratonic lithosphere with replacement to a lesser degree, and mantle plumes have been related to both destruction and rejuvenation. The role of continental subduction in craton modification, however, remains a comparatively open question. The North China Craton, as a previously stable continent with a lithosphere of more than 200 km since the Paleoproterozoic, was reworked and substantially destroyed since the Mesozoic, with intensive destruction occurring in the Early Cretaceous. Earlier in the Mesozoic, North China Craton experienced a continent-continent collision (as the upper plate) with the South China Block, forming the Sulu orogenic belt, providing an opportunity to understand the potential for craton modification due to deep continental subduction In the North China craton, we report the presence of material (i.e., Yunshan unit) sourced from the underlying subducted plate. It is composed of foliated monzonitic granite and metamorphic sedimentary rocks that locally experienced crustal anatexis. Through detailed zircon U-Pb dating, it formed at latest Triassic (ca. 212 Ma). Importantly, the 800–700 Ma inherited zircons from the Yunshan foliated granite resemble those from the South China Block rather than the North China Craton. According to structural and magnetic data, the fabrics of the Yunshan foliated granite, characterized by gentle magnetic/mesoscopic foliations and conspicuous NW-SE-trending magnetic/mesoscopic lineations with a top-to-the-NW shearing. Its geometry, kinematics, and timing all compare favorably with the latest Triassic extensional structure accounting for the exhumation of the Sulu orogenic belt. We thus interpret the Yunshan unit to have been sourced from the subducted South China Block, then exhumed and emplaced into the overriding North China Craton (Fig. 1A). Combining our new results with previous geological and geophysical data, we argue that from 250–220 Ma a 200-km-long tract of North China Craton lithosphere was bulldozed by the subducted South China Block, resulting in a lithospheric suture far from the suture zone at the surface. This lithospheric removal occurred at mid-lower crustal levels (16–20 km depth)  – much shallower than previously thought possible. The bulldozed North China Craton lithosphere was simultaneously replaced by the reworked underlying South China Block plate. Such a “bulldoze and rebuild” lithospheric modification process minimized asthenosphere-lithosphere interaction, thus preventing the North China Craton from further modification (Fig. 1B–1D). Because there was essentially no net loss of lithosphere during deep continental subduction, the North China Craton largely maintained its stability for the time and did not suffer intensive destruction until later Early Cretaceous palaeo-Pacific oceanic subduction. This “bulldoze and rebuild” model can thus account for how a craton can maintain its stability during a collision with another continental plate.
Źródło:
Geotourism / Geoturystyka; 2023, 1-2 (72-73); 47--48
1731-0830
Pojawia się w:
Geotourism / Geoturystyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Correlation of chromosome damage and promoter methylation status of the DNA repair genes MGMT and hMLH1 in Chinese vinyl chloride monomer (VCM)-exposed workers
Autorzy:
Wu, Fen
Liu, Jing
Qiu, Yu-Lan
Wang, Wei
Zhu, Shou-Min
Sun, Pin
Miao, Wen-Bin
Li, Yong-Liang
Brandt-Rauf, Paul W.
Xia, Zhao-Lin
Powiązania:
https://bibliotekanauki.pl/articles/2179802.pdf
Data publikacji:
2013-03-01
Wydawca:
Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:
vinyl chloride monomer
chromosome damage
MGMT
hMLH1
DNA methylation
Opis:
Objective: To explore the association of the methylation status of MGMT and hMLH1 with chromosome damage induced by vinyl chloride monomer (VCM). Materials and Methods: Methylation of MGMT and hMLH1 was measured in 101 VCM-exposed workers by methylation-specifi c PCR. Chromosome damage in peripheral blood lymphocytes was measured by the cytokinesis-block micronucleus assay. The subjects were divided into chromosome damaged and non-damaged groups based on the normal reference value of micronuclei frequencies determined for two control groups. Results: MGMT promoter methylation was detectable in 5 out of 49 chromosome damaged subjects, but not in the chromosome non-damaged subjects; there was a signifi cant difference in MGMT methylation between the two groups (p < 0.05). Conclusions: We detected aberrant promoter methylation of MGMT in a small number of chromosome damaged VCM-exposed workers, but not in the chromosome non-damaged subjects. This preliminary observation warrants further investigation in a larger study.
Źródło:
International Journal of Occupational Medicine and Environmental Health; 2013, 26, 1; 173-182
1232-1087
1896-494X
Pojawia się w:
International Journal of Occupational Medicine and Environmental Health
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of High-Temperature Annealing on the Cross-Tension Property of Resistance Spot Welded Medium-Mn Steel
Autorzy:
Zhao, Bingge
Wang, Yuanfang
Sun, Chenyu
Ding, Kai
Wu, Guanzhi
Wei, Tao
Pan, Hua
Gao, Yulai
Powiązania:
https://bibliotekanauki.pl/articles/2174565.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
medium Mn steel
resistance spot welding
cross-tension strength
martensite
fracture
Opis:
As one of the most promising 3rd generation advanced high strength steels (AHSS), medium Mn steels attract much attention because of their exceptional mechanical property and reasonable cost. However, their application in the modern automotive industry is limited by poor weldability. In this study, 7Mn steel was welded by resistance spot welding (RSW), which was followed by high-temperature annealing to increase the cross-tension property. With this effort, enhanced cross-tension strength (CTS) with a partial interfacial fracture (PIF) mode was realized. During the annealing after RSW that produced martensite, austenitization was realized and then evolved into martensite by the following air cooling. This process produced structure homogeneity across the joint. With respect to the RSW joint, martensite remained the dominant structure after annealing while the diffusion of C and Mn solutes was triggered. With the increase of annealing temperature, the diffusion was enhanced, and the grain boundary embrittlement was reduced, leading to higher CTS.
Źródło:
Archives of Metallurgy and Materials; 2022, 67, 4; 1293--1298
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of Welding Heat Input on Microstructure and Corrosion Characterization in CGHAZ of X80 Pipeline Steel
Autorzy:
Wang, Xue-Mei
Zhao, Wei
Chen, Kai
Li, Zhen
Powiązania:
https://bibliotekanauki.pl/articles/28099607.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
X80 pipeline steel
coarse grain heat-affected zone
heat input
corrosion
Opis:
The coarse-grained heat-affected zone specimens of X80 pipeline steel were produced by welding thermal simulation under different heat inputs of 10, 30, and 55 kJ/cm to study the effects of heat input on microstructure evolution and corrosion characterization. The corrosion resistance of coarse-grained heat-affected zones was poorer than that of base metal due to less homogenous in the former. For 10 kJ/cm coarse-grained heat-affected zone, the corrosion resistance was poorer than the others due to the more adsorption hydrogen around the needle-like martensite/austenite constituents and greater galvanic driving force between the needle-like martensite/austenite constituents and ferrite. In carbonate/bicarbonate solution, better corrosion resistance for coarse-grained heat-affected zones was obtained when the heat input is 30 kJ/cm, which can be attributed to the severe coarse martensite/austenite constituents for 55 kJ/cm coarse-grained heat-affected zone. In the H2S environment, the better corrosion resistance for coarse-grained heat-affected zone was obtained when the heat input is 55 kJ/cm, which can be attributed to the protective effect of corrosion products. In addition, the high content of M/A constituents for 30 kJ/cm CGHAZ was good for hydrogen adsorption, which was adverse to the corrosion resistance in acid environments.
Źródło:
Archives of Metallurgy and Materials; 2023, 68, 2; 659--671
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electrokinetic and flotation behavior of rutile in the presence of lead ions and aluminium ions
Autorzy:
Cheng, Hongwei
Liu, Changmiao
Guo, Zhenxu
Feng, Ansheng
Wei, Min
Lv, Zihu
Wu, Dongyin
Zhao, Dengkui
Powiązania:
https://bibliotekanauki.pl/articles/110558.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
lead ions
aluminium ions
rutile
flotation
Opis:
The effects of Pb(II) ions and Al(III) ions on the electro kinetic and flotation behavior of rutile were investigated by micro-flotation tests, zeta potential measurements and solution chemistry analysis. Micro-flotation results indicate that the Pb(II) ions can effectively improve the flotation recovery of rutile while the Al(III) ions significantly inhibit the flotation of rutile. Zeta potential measurements reveal that a collector styrene phosphoric acid (SPA) can adsorb on the rutile surface after the addition of Pb(II) ions, but hardly adsorb on the rutile surface after the addition of Al(III) ions. Pb(II) ions adsorb on the rutile surface in the form of Pb(OH)+ and Pb(OH)2(s), and the latter one is the main reason that activates rutile flotation. Al(III) ions adsorb on the rutile surface mainly in the form of Al(OH)3(s), which prevent the direct interaction between the rutile and the collector, resulting in a decrease of rutile flotation recovery.
Źródło:
Physicochemical Problems of Mineral Processing; 2019, 55, 2; 458-466
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Flotation separation of quartz from phosphorite using an imidazole ionic liquid collector and its adsorption mechanism
Autorzy:
Zhao, Yuanyuan
Xu, Wei
Mei, Guangjun
Yu, Mingming
Yang, Siyuan
He, Zhan
Powiązania:
https://bibliotekanauki.pl/articles/2146857.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
reverse flotation
imidazole ionic liquid
desilication
phosphorite
quartz
Opis:
In this study, an imidazole ionic liquid (dodecyl-tri-methylimidazolium chloride) was employed as a collector to separate quartz from phosphorite. The micro-flotation experiments of a single mineral found that it had selective collecting ability for quartz than phosphorite. Mixed mineral flotation experiments confirmed that efficient separation results could be obtained using the imidazole ionic liquid as the collector. A concentrate with a 31.44% grade of phosphorite could be obtained with a 0.285 kg/Mg collector dosage at neutral pH, which was much better than the traditional collector dodecylamine. The adsorption mechanism of the imidazole ionic liquid on the surface of phosphorite and quartz was investigated by contact angle and zeta potential measurements, Fourier transform infrared and X-ray photoelectron spectroscopy analyses. These results showed that the adsorption of imidazole ionic liquid at the quartz surface was stronger than that of phosphorite, and the collector adsorbability difference between quartz and phosphorite resulted in the efficient flotation separation. Consequently, the dodecyl-tri-methylimidazolium chloride salt is an effective collector for reverse flotation of quartz from phosphorite.
Źródło:
Physicochemical Problems of Mineral Processing; 2022, 58, 1; 159--168
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mineral investment risk assessment of host countries based on a cloud matter-element model
Ocena ryzyka inwestycji w minerały w krajach przyjmujących w oparciu o model chmury materii i pierwiastka
Autorzy:
Hou, Jie
Li, Guoqing
Ling, Jiahong
Chen, Lianyun
Zhao, Wei
Sheng, Baoli
Powiązania:
https://bibliotekanauki.pl/articles/27311628.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Instytut Gospodarki Surowcami Mineralnymi i Energią PAN
Tematy:
mineral investment
cloud matter element model
investment risk
risk assessment
inwestycje w surowce mineralne
model materii chmury
ryzyko inwestycyjne
ocena ryzyka
Źródło:
Gospodarka Surowcami Mineralnymi; 2023, 39, 4; 23--48
0860-0953
Pojawia się w:
Gospodarka Surowcami Mineralnymi
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mineralogical factors affecting the separation behavior of Ta-Nbbearing minerals in the gravity field: mineral grain size, liberation, and association relationship
Autorzy:
Cheng, Hongwei
Xu, Jian
Wang, Shoujing
Lv, Zihu
Wei, Fushuai
Zhao, Dengkui
Wu, Dongyin
Powiązania:
https://bibliotekanauki.pl/articles/27323650.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
separation behavior
gravity field
mineralogical characteristic
columbite-tantalite
association relationship
liberation
Opis:
Gravity separation is the primary method used to beneficiate Ta-Nb-bearing minerals, however, it performs poorly in low-grade and fine-grained ores. A comparative study of gravity separation products (concentrate, middlings, and tailings) reveals the factors affecting the separation behavior of Ta-Nb-bearing minerals in the process combined with a spiral chute and shaking table from the perspective of mineralogy. The results reveal that columbite-tantalite is the principal Ta-Nb-bearing mineral. As the grinding time increases, the grade of Ta and Nb in concentrate increases significantly. The grain size of columbite-tantalite in the concentrate is the coarsest, followed by that in the middlings, and the finest in the tailings, which are mainly distributed in the range of -150+38 μm, -75+20 μm, and -38 μm, respectively. The liberation degree of columbite-tantalite in the concentrate and tailings is positively correlated with grinding time, while that in the middlings is negatively correlated with grinding time. The density of columbite-tantalite-bearing particles in concentrate is mainly distributed above 3 or even 4, due to the high liberation degree of the columbite-tantalite in the concentrate, as well as the high amount of rich intergrowth associated with heavy minerals. The density of Ta-Nb-bearing mineral particles in the middlings and tailings is predominantly distributed in D<3, owing to columbite-tantalite mainly associated with lighter gangue minerals such as quartz, albite, and orthoclase. It demonstrates that the liberation degree is not the most essential factor in determining columbite-tantalite separation behavior in the gravity field, and the mineralogical characteristics of columbite-tantalite including grain size, association relationship, and particle density, may be more important. The results of this investigation can provide theoretical support for the strengthening separation of low-grade tantalum-niobium ore.
Źródło:
Physicochemical Problems of Mineral Processing; 2023, 59, 6; art. no. 174504
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł

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