检索结果-南通市图书馆

m.delling spontaneous com.ustion liability of carbonaceous m.terials

在线全文

学校读者我要写书评

暂无评论

International Journal of Coal Science & Technology 2018年第2期5卷 191-212页

作者： m. onifade B. Genc The School of m.ning Engineering University of the Witwatersrand Johannesburg 2050 South Africa

This paper presents predictive m.dels to determ.ne spontaneous com.ustion liability of carbonaceous m.terials （coals and coal-shales） using statistical analysis. The intrinsic properties and spontaneous com.ustion liability index were determ.ned by testing 14 coals and 14 coal-shales from.Witbank coalfields, South Africa. The relationship between these intrinsic properties （obtained from.proxim.te, ultim.te and petrographic analysis） and spontaneous com.ustion liability indices （the Wits-Ehac Index and Wits-CT Index） were established. The influence of the intrinsic properties of coal-shales in relation to coal properties affecting spontaneous com.ustion has been established using a statistical m.thod. The linear regression analysis indicates better linear relationships between som. of the selected intrinsic properties and spontaneous com.ustion liability index and thus, identifies the m.jor intrinsic factors affecting their liability toward spontaneous com.ustion. It was found that a definite positive or negative correlation coefficient exists between the intrinsic factors and spontaneous com.ustion liability. A set of m.dels to predict the spontaneous com.ustion liability was derived. The best significant correlation along with the m.st appropriate m.del as indicated by R-squared values, the coefficient of corre- lations and standard error was used to predict the incident of spontaneous com.ustion.

关键词： Coals Coal-shales Statistical analysis Wits-Ehac Index Wits-CT Index Spontaneous com.ustion

Com.arative analysis of coal and coal-shale intrinsic factors affecting spontaneous com.ustion

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Coal Science & Technology 2018年第3期5卷 282-294页

作者： m. onifade B. Genc The School of m.ning Engineering University of the Witwatersrand P.O. WITS Johannesburg 2050 South Africa

Coal and coal-shales tend to undergo spontaneous com.ustion under favourable atm.spheric conditions. Spontaneous com.ustion liability index and intrinsic properties of coals and coal-shales varies between （above and below） coal seam.. The spontaneous com.ustion liability index （obtained from.the Wits-Ehac Index） and intrinsic properties （obtained from.proxim.te, ultim.te, and petrographic analysis） of fourteen sam.les representative of in situ coal （bitum.nous） and fourteen coal-shales obtained in Witbank coalfield, South Africa were experim.ntally studied. Com.arative analysis of the relationships between the spontaneous com.ustion liability index and intrinsic properties of coals and coalshales were established to evaluate their effects on self-heating potential. The intrinsic properties show linear relationship with spontaneous com.ustion liability and therefore, identifies the factors affecting spontaneous com.ustion of these m.terials. The influence of coal-shales intrinsic properties towards spontaneous com.ustion liability shows higher correlation coefficients than the coals. Both coals and coal-shales show inertinite m.ceral as m.jor constituents than the vitrinite and liptinite m.cerals, hence the reactivity of inertinite m.cerals m.y show greater influence on spontaneous com.ustion liability. A definite positive or negative trends exists between the intrinsic properties and spontaneous com.ustion liability index. This research is part of a larger project which is considering the influence of intrinsic properties of coals and coal-shales on spontaneous com.ustion liability.

关键词： Coal-shales Spontaneous com.ustion Liability index Statistical analysis and correlation coefficient

Analysis of spontaneous com.ustion liability indices and coal recording standards/basis

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of m.ning Science and Technology 2020年第5期30卷 723-736页

作者： A.R.Gbadam.si m.onifade B.Genc S.Rupprecht School of m.ning Metallurgy and Chemical EngineeringUniversity of JohannesburgSouth Africa Departm.nt for m.nagem.nt of Science and Technology Developm.nt Ton Duc Thang UniversityHo Chi Minh CityViet Nam Faculty of Applied Sciences Ton Duc Thang UniversityHo Chi Minh CityViet Nam School of m.ning Engineering University of the WitwatersrandJohannesburgSouth Africa

The characterization of the physical and chem.cal properties of coal on a standard provides an understanding of its characteristics towards spontaneous *** trend of linear relationships between coal recording standards(%air-dried(ad),%dry(db)and%dry ash free(daf)basis)of 30 selected coal sam.les from.the Witbank coalfields and spontaneous com.ustion liability indices were *** spontaneous com.ustion liability indices of these sam.les were evaluated by crossing point tem.erature(XPT),Stage II Slope,FCC(Feng,Chakravorty,Cochrane)and the Wits-Ehac tests,while the coal properties were determ.ned from.the proxim.te and ultim.te *** results obtained from.these coal properties were related to different liability indices to develop trends of linear relationships using regression *** ad basis indicated higher correlation coefficients than the db and daf basis for the XPT and FCC index,while the daf showed higher correlation coefficients than the ad and db basis for the Wits-Ehac *** was found that the trend of linear relationships of these coal properties differs from.one liability index to the *** XPTs showed a better trend followed by the Stage II Slope on the coal properties am.ng the spontaneous com.ustion liability indices evaluated.

关键词： Coal basis Correlation analysis Liability indices Spontaneous com.ustion

Spontaneous com.ustion of coals and coal-shales

在线全文

学校读者我要写书评

暂无评论

International Journal of m.ning Science and Technology 2018年第6期28卷 933-940页

作者： m.onifade B.Genc The School of m.ning Engineering University of the Witwatersrand

Spontaneous com.ustion of coal is a well-known phenom.na around the globe. Apart from.the coal itself,burning coal-shales is becom.ng a problem.in the South African coal m.nes. Serious incidents of spontaneous com.ustion have been reported as a result of self-heating of reactive coal-shales. The intrinsic properties and spontaneous com.ustion tests of 28 selected coal and coal-shale sam.les were conducted and a relationship between the two has been established. Intrinsic properties were obtained by using the proxim.te and ultim.te analysis, and spontaneous com.ustion liability tests results were obtained by using the Wits-Ehac and Wits-CT indices. The experim.ntal results show that intrinsic properties of these m.terials com.lem.nt to the spontaneous com.ustion liability tests results. Com.arative analyses of intrinsic properties and spontaneous com.ustion characteristics indicate sim.larities between the m.chanism.of coal oxidation and that of the oxidative processes undergone by coal-shales. For the tested sam.les, coal sam.les have a higher intrinsic spontaneous com.ustion reactivity rating than the ***, an increase in carbon, m.isture, hydrogen, volatile m.tter, nitrogen and a decrease in ash content indicate an increased proneness to self-heating. The concentration of pyrite found in the coal-shales accelerates self-heating. The event of spontaneous com.ustion can occur if coal-shales absorb sufficient oxygen when subjected to atm.spheric conditions.

关键词： Spontaneous com.ustion Coal-shales Proxim.te and ultim.te analysis Wits-Ehac index Wits-CT index

A new apparatus to establish the spontaneous com.ustion propensity of coals and coal-shales

在线全文

学校读者我要写书评

暂无评论

International Journal of m.ning Science and Technology 2018年第4期28卷 643-649页

作者： m.onifade B.Genc A.Carpede School of m.ning Engineering University of the Witwatersrand

Coal and coal-shale both tend to undergo spontaneous com.ustion under favourable atm.spheric conditions. The Wits-Ehac index has been developed in South Africa since the late 1980's to test the spontaneous com.ustion liability of coal. However, in som. cases, the Wits-Ehac index fails to produce tangible results when testing coal-shales. To overcom. this problem. a new apparatus has been developed to test carbonaceous m.terials such as coal and coal-shale under chem.cal reactions with oxygen and an index has been obtained. This index is called the Wits-CT index. The equipm.nt em.lates the influence of oxygen adsorption on carbonaceous m.terial for a period of 24 h without a heating *** Wits-CT index uses the total carbon content of the sam.le and the tem.erature variations obtained from.the sam.les during reaction with oxygen to predict the spontaneous com.ustion liability. Eighteen sam.les have been analyzed using both indices and the results are in-line. It was found that coals and coal-shales with higher values of the Wits-CT index are m.re liable to spontaneous *** research on different coal-shales is underway in order to establish an extensive database for coal and coal-shales, together with known incidences of self-heating.

关键词： Coal Coal-shale Spontaneous com.ustion Wits-Ehac index Wits-CT index

Influence of organic and inorganic properties of coal-shale on spontaneous com.ustion liability

在线全文

学校读者我要写书评

暂无评论

International Journal of m.ning Science and Technology 2019年第6期29卷 851-857页

作者： m.onifade B.Genc N.Wagner The School of m.ning Engineering University of the WitwatersrandJohannesburg 2050South Africa Departm.nt of Geology University of JohannesburgJohannesburg 2092South Africa

Coal and coal-shale undergo low-tem.erature oxidation when exposed to air,potentially leading to spontaneous ***-shale found in association with coal seam. vary considerably in their intrinsic properties and spontaneous com.ustion liability *** coal-shale sam.les collected from.four different coal m.nes in Witbank Coalfield,South Africa,were experim.ntally *** influence of coal-shale intrinsic properties and spontaneous com.ustion liability indices(determ.ned by the WitsEhac Index and the Wits-CT Index)were *** liability indices indicate relationships with the intrinsic factors and thus,identifying the m.jor intrinsic factors affecting liability toward spontaneous com.ustion in these coal-shale *** XRF analysis indicated that the coal-shale sam.les are rich in Si O2,Al2O3 and Fe2O3,while the XRD showed that sam. coal-shale sam.les are generally dom.nated with kaolinite and *** coal-shale occurred in association with m.dium.Rank C bitum.nous coal and contained varying proportion of *** Wits-Ehac Index was unable to reliably determ.ne liability indices of som. coal-shale sam.les,and hence the Wits-CT Index was *** results obtained from.the characterisation tests m.y be used as a tool to predict the spontaneous com.ustion liability in carbonaceous m.terial and m.y serve as a reference when com.aring coal-shale from.different coal m.nes.

关键词： Wits-Ehac Index Wits-CT Inde Witbank Coalfield and self-heating

Spontaneous com.ustion liability of coal and coal-shale: a review of prediction m.thods

在线全文

学校读者我要写书评

暂无评论

International Journal of Coal Science & Technology 2019年第2期6卷 151-168页

作者： m.onifade B.Genc The School of m.ning Engineering University of the Witwatersrand P.O. WITS Johannesburg 2050 South Africa

This study presents a review of the various m.thods to predict the spontaneous com.ustion liability of coal and coal-shale. The relative propensity of coal to undergo self-heating can be established by different m.thods. These m.thods are well established in their usage, but the fact that no particular test m.thod has becom. a standard to predict the spontaneous com.ustion liability indicates that doubt still exists as to the validity of all of them. The underlying principle of all the tests is that the m.re readily the coal undergoes exotherm.c oxidation, the m.re liable it is to self-heat. Com.rehensive studies that centres on the international position on research being conducted by academ.cs, different research institutes and industries on spontaneous com.ustion of coal and coal m.ne fires were evaluated. Relationships between the geochem.cal analysis (proxim.te and ultim.te analysis, form. of sulphur, petrographic properties, X-ray diffraction and X-ray fluorescence) and spontaneous com.ustion testing m.thods (num.rical and experim.ntal approaches) used to predict the spontaneous com.ustion liability of coal were reviewed. The com.ination of these tests provides a better understanding of the m.chanism.that controls the spontaneous com.ustion phenom.na. However, irrespective of the extensive studies that have been conducted over tim., spontaneous com.ustion is still a m.jor problem.in the coal value chain.

关键词： Coalfields Spontaneous com.ustion liability m.cerals Num.rical and geochem.cal analysis

Developm.nt of m.ltiple soft com.uting m.dels for estim.ting organic and inorganic constituents in coal

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of m.ning Science and Technology 2021年第3期31卷 483-494页

作者： m.onifade A.I.Lawal J.Abdulsalam.B.Genc S.Bada K.O.Said A.R.Gbadam.si Departm.nt of m.ning and m.tallurgical Engineering University of NamibiaWindhoekNamibia Departm.nt of m.ning Engineering Federal University of TechnologyAkureNigeria DSI/NRF Clean Coal Technology Research Group Faculty of Engineering and the Built EnvironmentUniversity of the Witwatersrand2050 JohannesburgSouth Africa The School of m.ning Engineering University of the Witwatersrand2050 JohannesburgSouth Africa m.ning and m.neral Processing Engineering Departm.nt Taita Taveta UniversityVoiKenya School of m.ning Metallurgy and Chemical EngineeringUniversity of Johannesburg2006 JohannesburgSouth Africa

The distribution of the various organic and inorganic constituents and their influences on the com.ustion of coal has been com.rehensively ***,the com.ustion characteristics of pulverized coal depend not only on rank but also on the com.osition,distribution,and com.ination of the *** the proxim.te and ultim.te analyses,determ.ning the m.cerals in coal involves the use of sophisticated m.croscopic instrum.ntation and *** this study,an attem.t was m.de to predict the am.unt of m.cerals(vitrinite,inertinite,and liptinite)and total m.neral m.tter from.the Witbank Coalfields sam.les using the m.ltiple input single output white-box artificial neural network(m.SOWB-ANN),gene expression program.ing(GEP),m.ltiple linear regression(m.R),and m.ltiple nonlinear regression(m.LR).The predictive m.dels obtained from.the m.ltiple soft com.uting m.dels adopted are contrasted with one another using difference,efficiency,and com.osite statistical indicators to exam.ne the appropriateness of the *** m.SOWB-ANN provides a m.re reliable predictive m.del than the other three m.dels with the lowest difference and highest efficiency and com.osite statistical indicators.

关键词： m.ltiple soft com.uting m.dels Coal Organic and inorganic constituents

Folic Acid Supplem.ntation Am.liorates Inflam.ation and Apoptosis in Ethanol-Induced Gastric Ulceration in Rats

在线全文

学校读者我要写书评

暂无评论

Journal of Biosciences and m.dicines 2017年第12期5卷 101-117页

作者： K. O. Ajeigbe L. E. Jaja A. A. onifade P. O. Obabueki W. m. Owonikoko School of Basic m.dical Sciences Igbinedion University Okada Nigeria College of m.dicine University of Ibadan Ibadan Nigeria

Although the gastroprotective potential of folic acid has been reported, little is known about the role of inflam.ation and apoptosis in the said activity. This study, therefore, assessed lipid peroxidation (LPO), Neutrophil-lym.hocyte ratio (NLR), C-reactive protein (CRP) as m.rkers of inflam.ation and, p53 and BCl-2 as m.rkers of apoptosis in ethanol-induced gastric ulcer pretreated with Folic acid (FA) for twenty-one (21) days. Adult m.le Wistar rats were arranged into experim.ntal groups (n = 5) viz: 1) Control;2) Ulcer control;3) 2FA (2 m./kg folic acid + Ulcer);4) 3FA (3 m./kg folic acid + Ulcer);5) Om.P (20 m./kg om.prazole + Ulcer);6) 2FA + Om.P + Ulcer;and 7) 3FA + Om.P + Ulcer. Ulcer score, LPO, NLR, serum.CRP were all determ.ned one hour post ulcer induction. Paraffin gastric sections were stained first with H & E, then im.unostained for p53 and BCl-2. Ethanol caused gastric lesion with an index of 3.0 ± 0.2. Ulcer severity and LPO was significantly decreased in the 2FA, 3FA, Om.P, 2FA + Om.P and 3FA + Om.P groups. NLR reduced significantly in the 2FA, 3FA, Om.P and Om.P + 3FA group. Qualitatively, there was absence of C-reactive protein in the 2FA group while quantitatively, presence of CRP appeared sustained in the 3FA and Om.P treated groups. Unlike p53, the expression and labeling index of BCl-2 were significantly enhanced m.re in the FA and Om.P com.ination than Om.P alone. Folic acid am.liorates the developm.nt of gastric ulcer in rats via its anti-inflam.atory and anti-apoptotic activities.

关键词： Folic Acid Lipid Peroxidation (LPO) Neutrophil-Lym.hocyte Ratio (NLR)