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Wyszukujesz frazę "Leite, A." wg kryterium: Autor


Wyświetlanie 1-5 z 5
Tytuł:
Tailings reprocessing from Cabeco do Piao dam in Central Portugal: a kinetic approach of experimental data
Autorzy:
Figueiredo, J.
Vila, M. C.
Matos, K.
Martins, D.
Futuro, A.
de Lurdes Dinis, M.
Góis, J.
Leite, A.
Fiúza, A.
Powiązania:
https://bibliotekanauki.pl/articles/92190.pdf
Data publikacji:
2018
Wydawca:
Główny Instytut Górnictwa
Tematy:
tailings
multi-criteria optimization
reprocessing
zinc
tungsten
odpadki
optymalizacja wielokryterialna
utylizacja
cynk
wolfram
Opis:
The mining waste and tailing dam are object of discussion due to the accidents that occur due to a lack of control or due to interest in the remaining minerals present in these materials. Most of the old tailings dams have high contents of heavy metals which could represent potential risks to the environment or be an alternative source of some critical raw materials. The case study of the Cabeco do Piao dam in Central Portugal involved tailings from a processing plant that belonged to the Panasqueira Mine Complex, which has been in operation for over 120 years. Waste rock and mining tailings were deposited in the area until 1995, and they represent an environmental liability for the local population due to their high content of toxic metals. Tailings reprocessing can be considered as a solution that minimizes social and environmental impacts, recovers some essential minerals, such as Zn, W, and Cu which can help to offset investments made. The project design involves several stages of metal concentration, determined by experiments, as well as a model of the process. The overall model will take into account technological constraints, social-economic conditions and environmental impacts. A preliminary result of an optimization study of the kinetic approach is presented in this piece of work.
Źródło:
Journal of Sustainable Mining; 2018, 17, 3; 139-144
2300-1364
2300-3960
Pojawia się w:
Journal of Sustainable Mining
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Immobilization and experimental periodontitis in tibial anterior muscle of wistar rats
Autorzy:
Wutzke, M.L.S.
Leite, A.M.
Nassat, C.A.
Nassar, P.O.
Brancalhao, R.M.C.
Bertolini, G.R.F.
de Fatima Chasko Ribeiro, L.
Powiązania:
https://bibliotekanauki.pl/articles/3205.pdf
Data publikacji:
2019
Wydawca:
Instytut Medycyny Wsi
Źródło:
Journal of Pre-Clinical and Clinical Research; 2019, 13, 1
1898-2395
Pojawia się w:
Journal of Pre-Clinical and Clinical Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Unidirectional Protection Strategy for Multi-terminal HVDC Grids
Autorzy:
Mokhberdoran, A.
Silva, N.
Leite, H.
Carvalho, A.
Powiązania:
https://bibliotekanauki.pl/articles/136202.pdf
Data publikacji:
2016
Wydawca:
EEEIC International Barbara Leonowicz Szabłowska
Tematy:
DC circuit breaker
HVDC
Protection Device
voltage source converter (VSC)
Short-circuit
Opis:
Protection issue is identified as the main drawback of emerging multi-terminal HVDC grids. Multi-terminal HVDC grid demands fast short circuit fault current interruption. Fast DC circuit breakers as a promising solution can be implemented as either bidirectional or unidirectional devices. In addition to less implementation cost, the unidirectional DC circuit breakers have less power losses as compared to the bidirectional devices. A protection strategy for multi-terminal HVDC grid based on unidirectional breaking devices is discussed and assessed in this paper. The performance of unidirectional protection strategy is examined under different fault scenarios in a fourterminal MMC-HVDC grid model. Furthermore, the impacts of unidirectional protection strategy on power converters and also current interruption and surge arrester ratings of the DC circuit breakers are discussed.
Źródło:
Transactions on Environment and Electrical Engineering; 2016, 1, 4; 58-65
2450-5730
Pojawia się w:
Transactions on Environment and Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Froth flotation of Aljustrel sulphide complex ore
Autorzy:
Sousa, R.
Futuro, A.
Pires, C. S.
Leite, M. M.
Powiązania:
https://bibliotekanauki.pl/articles/109732.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
froth flotation
mineral liberation
flotation reagents
complex sulphide ore
Opis:
Froth flotation of copper-zinc-lead ores is a complex process based on similar metallurgy processing and strong interactions between chalcopyrite and sphalerite. These types of ores represent 15% of the world production and 7.5% of copper deposits all over the world. In the present study, an attempt is made to assess the feasibility of froth flotation of a complex sulphide ore, where the effect of liberation grade as well as depressant, collector and frother dosage was studied. Copper flotation is dependent on the mineral liberation grade, which is significantly related with the size distribution. It was shown that longer grinding time increased the Cu grade but decreased the copper recovery due to the presence of very fine particles. Lime and sodium metabisulphite, used as depressants, allowed to achieve a good flotation performance. It was shown that for this type of ore lower dosage of the collector should be applied. Finally, a higher frother dosage led to a greater selectivity and reduced entrainment of very fine particles, but also caused low kinetic ratio and low recovery of valuable minerals. A well-defined flotation objective was imperative for a good liberation grade and reagents dosage selection, mainly for complex sulphide ores. A useful contribute was given to a better technical understanding of flotation of a complex sulphide ore from the Moinho deposit.
Źródło:
Physicochemical Problems of Mineral Processing; 2017, 53, 2; 758-769
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phytochemical potential of Ficus species for the control of the phytonematode Meloidogyne javanica
Autorzy:
Alves, J.R.
De Assis, J.N.
Padua, C.C.A.
Balbino, H.M.
Lima, L.L.
De Souza Gouveia, A.
Vital, C.E.
Buonicontro, D.S.
De Freitas, L.G.
Leite, J.P.V.
De Oliveira Ramos, H.J.
Powiązania:
https://bibliotekanauki.pl/articles/2082765.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
gas chromatography/mass spectrometry (GC/MS)
metabolite profiling
pest
control
phytochemistry
Opis:
Root-knot nematodes, genus Meloidogyne, are among the most plant damaging pathogens worldwide. The action of natural products against plant pathogens has been investigated to assess their effectiveness in the control of diseases. Thus, the present study aimed to evaluate the phytochemistry potential of the Ficus species for the control of Meloidogyne javanica. In vitro inhibitory activity assays were performed with crude ethanolic extracts of leaves and branches from 10 Ficus species. Among these, Ficus carica extracts exhibited strong paralysis activity against second stage juveniles (J2) (EC50 = 134.90 μg ∙ ml–1 ), after 72 hours. In addition, high efficacy was observed in egg-hatching inhibition at different embryonic stages. Microscopy analysis revealed severe morphological alterations in the nematode tissues at the J2 stage, as well as immotility of juveniles released from eggs in the presence of F. carica extracts. The efficacy of the treatments for the other species was very low. These differences were supported by the variation in the compound classes, mainly for alkaloids and metabolite profiles by Gas Chromatography/Mass Spectrometry (GC/MS) when F. carica was compared with the other species. The results indicated that F. carica is a promising source for the isolation and identification of molecules capable of acting in the control of M. javanica.
Źródło:
Journal of Plant Protection Research; 2020, 60, 2; 193-206
1427-4345
Pojawia się w:
Journal of Plant Protection Research
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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