检索结果-南通市图书馆

The Sytykanskaya kimberlite pipe:Evidence from deep-seated xenoliths and xenocrysts for the evolution of the mantle beneath Alakit,Yakutia,Russia

在线全文

学校读者我要写书评

暂无评论

Geoscience Frontiers 2015年第5期6卷 687-714页

作者： I.V.Ashchepkov A.m.Logvinova L.F.Reimers T.Ntaflos Z.V.Spetsius N.V.Vladykin H.Downes D.S.Yudin A.V.Travin L.V.makovchuk V.S.Palesskiy o.S.Khmel'nikova Institute of Geology and mineralogy SB RAS Vienna University Alrosa Stock Company Institute of Geochemistry SB RAS Birkbeck College University of LondonUKMalet Street

mantle xenoliths（>150） and concentrates from late autolithic breccia and porphyritic kimberlite from the Sytykanskaya pipe of the Alakit field（Yakutia） were analyzed by EPmA and LAm ICP *** P-TX-f（o2） diagrams minerals from xenoliths show widest variations,the trends P-Fe#-Cao,f（o2）for minerals from porphyric kimberlites are more stepped than for xenocrysts from *** PTX points mark moving for protokimberlites from the lithosphere base（7.5 GPa） to pyroxenite lens（5-3.5 GPa） accompanied by cr increase by AFC and creation of two trends P-Fe#oI10-12%and13-15%.The opx-Gar-based mantle geotherm in Alakit field is close to 35 mW/m2 at 65 GPa and 600 C near moho was *** oxidation state for the megacrystalline ilmenites is lower for the metasomatic associations due to reduction of protokimberlites on peridotites than for uncontaminated varieties at the lithosphere *** inclined linear REE patterns with deep HFSE troughs for the parental melts of clinopyroxene and garnet xenocrysts from breccia were influenced by differentiated *** for metasomatic xenoliths reveal less inclined slopes without deep troughs in spider *** reveal S-shaped REE *** clinopyroxenes from graphite bearing cr-websterites show inclined and inflected in Gd spectrums with LREE variations due to AFC *** for garnets display less inclined patterns and Ba-Sr troughs but enrichment in ***40Ar/39Ar ages for micas from the Alakit mantle xenoliths for disseminated phlogopites reveal Proterozoic（1154 ma） age of metasomatism in early Rodinia *** glimmerites with richterite- like amphiboles mark1015 ma plume event in Rodinia ***600-550 ma stage manifests final Rodinia *** last 385 ma metasomatism is protokimberlite-related.

关键词： Kimberlites mantle lithosphere mantle xenoliths Th

Review on laboratory preparation processes of polymer modified asphalt binder

在线全文

学校读者我要写书评

暂无评论

Journal of Traffic and Transportation Engineering(English Edition) 2023年第2期10卷 159-184页

作者： m.A.Dalhat Khaleel Al-Adham Transportation and Traffic Engineering Department College of EngineeringImam Abdulrahman Bin Faisal UniversityDammam 31451Saudi Arabia Shibh Al-Jazira Contracting Company Dammam 32257Saudi Arabia

Several previous studies have documented the progress in polymer modified asphalt binder with respect to materials'types and ***,limited or no effort was made to document findings on the laboratory preparation practices of polymer modified asphalt *** and clear disclosure of asphalt blend preparation method is necessary for research continuity,reproducibility,and accurate adaptation by future studies for analogy and reliable *** laboratory preparation processes of various modified asphalt binders have been reviewed in this *** affecting the optimal mixing of asphalt-polymer blends were *** optimal mixing conditions associated with different asphalt modifiers were *** in the literature on the current practice for the preparation and reporting of various modified asphalt binder was *** include styrene butadiene styrene(SBS),polyethylene(PE),waste tire rubber or crumb rubber(cr),ethylene vinyl acetate(EVA),sulfur,polyphosphoric acid(PPA),epoxy,polyurethane,nano-materials,***,there is lack of modern innovative approached in the preparation of modified asphalt towards better *** is no clear standardized definition of term associated with asphalt binder preparation *** the limited and common types of polymers utilized for the modification of asphalt binder,it is possible to standardize the mixing procedure for several *** so could ease research continuity and facilitates accurate comparison of new studies with earlier ones.

关键词： Pavement engineering Polymer modified asphalt SBS PE Waste tire rubber

Characterization of cytotoxicity of airborne particulates from urban areas of Lahore

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2012年第11期24卷 2028-2034页

作者： Badar Ghauri m.mansha Christian Khalil Institute of Space Technology Karachi 72500Pakistan School of Risk and Safety Sciences University of New South WalesAustralia

A number of species （organic and inorganic） in airborne particulates cause the toxicity to living being. The potential of in vitro test methods were explored for toxicity assessment of trace toxic elements （inorganic species） present in ambient air on human being （lungs）. A year long sampling of airborne particles （Pm2.5） was carded （April 2008 to march 2009） in Lahore, Pakistan. A total of thirty nine samples were collected on 47 mm Zefiuor Teflon filter membranes and each was analysed to characterize for the elements： Sb, As, Be, Cd, cr, Co, Pb, mn, Hg using ICP-mS in water extract and total acid digestate. The samples cytotoxicity was also established using lung derived cells and mTS colorimetric assays. This generated dose response curves and IC50 values for the elemental mixtures identified on the Teflon filter membrane. The results indicated that even at low concentrations airborne elemental mixtures displayed an additive toxic effect.

关键词： particulate matter trace elements in vitro toxicity

Geochemistry of Late cretaceous (60-67 ma) igneous activities in the Hebrides Terrace seamount (guyot) area, Scotland

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Geochemistry 2005年第1期24卷 9-17页

作者： m. El-Tokhi m. omran A. El-muslem Geology Dept. Mansoura University Damietta 34517 EgyptGeology Dept. Mansoura University Damietta 34517 EgyptGeology Dept.United Arab Emirates University 17551 United Arab Emirates

Tholeiitic basalts in various stages of alteration were dredged from Late cretaceous volcanic rocks (60-67 ma) in the Hebrides Terrace seamount area in the Atlantic ocean. These rocks are extrusive olivine basalts, including high- and low-Al basalts. High-Al basalts are depleted in mgo, Cao, cr, Sc, V, Sr, Zr and enriched in Tio-2, Na-2o, Nb, Rb as compared with low-Al basalts. Petrography and bulk-rock composition (major, trace and rare-earth elements) data defined clear tholeiitic suites displaying possible liquid lines of descent related to different degrees of crystal fractionation and partial melting. Isotopic dating of dredged samples gave the guyot an age of 60-67 ma, in support of the assumption that it was formed during the Late cretaceous.

关键词：地球化学白垩纪硅采样标准火成活性苏格兰

Fractal interpolation:a sequential approach

在线全文

学校读者我要写书评

暂无评论

Applied mathematics(A Journal of Chinese Universities) 2021年第3期36卷 330-341页

作者： N.Vijender m.A.Navascus Department of mathematics Visvesvaraya National Institute of Technology NagpurNagpur 440010India Departamento de matem´atica Aplicada Escuela de Ingenier´ıa y ArquitecturaUniversidad de ZaragozaZaragoza 50018Spain

Fractal interpolation is a modern technique to fit and analyze scientific *** develop a new class of fractal interpolation functions which converge to a data generating(original)function for any choice of the scaling ***,our method offers an alternative to the existing fractal interpolation functions(FIFs).We construct a sequence of-FIFs using a suitable sequence of iterated function systems(IFSs).Without imposing any condition on the scaling vector,we establish constrained interpolation by using fractal *** particular,the constrained interpolation discussed herein includes a method to obtain fractal functions that preserve positivity inherent in the given *** existence of cr--FIFs is *** identify suitable conditions on the associated scaling factors so that-FIFs preserve r-convexity in addition to the cr-smoothness of original function.

关键词： fractal interpolation convergence sequence of operators constrained-FIFs fractal splines

Structural-Energy Characteristics of Tribotechnical Contact in Unsteady operational modes

在线全文

学校读者我要写书评

暂无评论

modern mechanical Engineering 2016年第3期6卷 91-97页

作者： Tareq m. A. Al-Quraan oksana o. mikosyanchik Rudolph G. mnatsakanov olexander I. Zаporozhets College of ma’an Al-Balqa’ Applied University Salt Jordan National Aviation University Kiev Ukraine

The current tribological research is intended to achieve maximum wear resistance under the structural adaptability of tribocoupling elements, which requires application of means to reduce the activation of the metal surface layers, decrease in frictional work, regulation of passivation and temperature control. The aim of this study is to identify the patterns that influence the kinetics formation of the boundary layers of lubricating mineral gear oil on activated friction contact surfaces, and the increment of the friction specific work on wear-resistant steel 42cr4 and 100cr6 in frequent start and stop operation mode. Due to the activation of surface layers of metal in the non-stationary operating conditions of the contact surfaces, the gradual forming of the boundary lubricant adsorption layers with increased effective viscosity in contact occurs, exhibiting high adaptation ability, and the boundary layer thickness is from 0.2 to 4 microns. This research analyzed the lubricating ability of oil at the starting maximum torque of friction, showing that the thickness of the oil layer formed in contact had a dual nature—boundary and hydrodynamic. The pure rolling conditions promote localization of shear in the lubricating layers, and the high frictional properties of the transmission oil have been identified regardless of the hardness of the investigated surfaces.

关键词： Friction Specific Work Kinetics Formation Boundary Layers Lubricating Layers Hardness

The chromite deposits associated with ophiolite complexes, Southeastern Desert, Egypt: Petrological and geochemical characteristics and mineralization

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Geochemistry 2006年第4期25卷 307-317页

作者： Gehad m. Saleh Nuclear materials Authority P.O.Box: 530 El Maadi Cairo Egypt

The podiform chromitites occur in a well-preserved mantle sequence consisting of lherzolite-harzburgite with abundant lenses of olivine dunite. The podiform chromitite deposits are common as small and irregularly shaped masses in the Southeastern Desert (SED) of Egypt. The podiform chromitites exhibit a wide range of compositions from high cr to high Al varieties. The cr of chrome spinel ranges from 0.67 to 0.88 in olivine-dunite, quite similar to that of the high-cr chromitite, whereas it is around 0.62 in lherzolite-harzburgite. Primary hydrous mineral inclusions, amphibole and phlogopite, in chrome spinel have been reported for the first time from the Pan-African Proterozoic podiform chromitites. on the other hand, petrographic and geochemical evidence suggests that podiform chromitites in the SED of Egypt were formed as a result of crystallization of mafic melts, probably of boninitic composition, the boninitic parental magmas were probably produced by a second stage of melting above a subduction zone. Three types of chromite ores can be distinguished within the SED of Egypt: (a) sulphide-poor podiform ores; (b) brecciated ores; and (c) sulphide-rich ores. Two textural types of inclusions in chromite are distinguished: (1) primary silicate inclusions generally have high mg-number (>96), cr and Ni, and are dominated by pargasitic amphibole, forsterite, diopside, enstatite and Na-phlogopite. A diversity of primary and secondary platinum group minerals (PGm) is described from the chromitites, including alloys, sulphides, sulpharsenides and arsenides of Ru, os, Ir, Rh, Ni, Cu, Fe and Co; (2) in addition to primary PGm and hydrous silicates, the fluids are of low to moderate salinity, sodium-dominated aqueous solutions with complex gas contents. Variable amounts of water, hydrogen, hydrocarbons, carbon dioxides and nitrogen have been determined in inclusion-rich samples. The chondrite-normalized PGE patterns of lherzolite-harzburgite and olivine-dunite have negative

关键词：铬铁矿沉淀蛇绿岩复合物东南沙漠埃及岩石学

Inventory of Estuarine and Lagoonal Ecosystems Subjected to Sand-mining Activities in Southern Benin (West Africa)

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Protection 2019年第4期10卷 473-487页

作者： Romaric K. Lalèyè Hyppolite Agadjihouèdé Antoine Chikou Hamed Adjagbo crépin Assogba Djiman Lédéroun Philippe A. Lalèyè Laboratory of Hydrobiology and Aquaculture (LHA) Faculty of Agricultural Sciences University of Abomey-Calavi Cotonou Republic of Benin Unity of Research in Aquaculture Aquatic Biology and Ecology/Laboratory of Animals and Halieutics Science (URABEA/LaSAH) School of Aquaculture National University of Agriculture Kétou Republic of Benin

Sand is a useful resource for the development of any society. As such, the issues related to its extraction are everywhere present in Benin, especially in the southern part of the country. For the purposes of eventually characterizing those issues, the present study is undertaken with a focus on inventorying estuarine and lagoonal ecosystems which are subjected to sand mining in southern Benin. The study area covers both the Eastern Complex and the Western Complex. The Eastern Complex includes the Porto-Novo Lagoon and the ouémé River delta;while the Western Complex includes the Coastal Lagoon, the Aheme Lake along with its channels, and the mono Basin. The method used in this study is a systematic inventorying of all known and documented sites as kept on record with relevant state offices in charge of the management of those resources. Then, the data were completed by combing the whole area for direct census observations and field interviews with stakeholders. All inventoried sites have been geo-referenced using a GARmIN GPS and their surface areas have been established. To date, 43 sand-mining sites have been identified, of which 29 are located in the oueme Delta and in the Porto-Novo Lagoon, 8 are in the Coastal Lagoon, and 6 are in the Aheme Lake and its channels as well as in the mono River basin. The areas are small in the oueme Delta, where extraction is mostly manual, but get to be more than 89-ha wide in other places such as the Coastal Lagoon where the process is rather mechanized.

关键词： Inventory Sand-Dredging Aquatic Ecosystems Southern Benin

Temperature effect on the corrosion and passivation characterization of Ni_(82.3)cr_7Fe_3Si_(4.5)B_(3.2) alloy in acidic media

维普期刊数据库评论

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 minerals,metallurgy and materials 2016年第2期23卷 205-214页

作者： Khadijah m.Emran Sanaa T.Arab Aisha m.Al-Turkustani Hamad A.Al-Turaif Chemistry Department Faculty of Science Taibah University Department of Chemistry Faculty of Sciences Al-Faisaliah King Abdulaziz University Department of Chemical and materials Engineering King Abdulaziz University

The effects of temperature on corrosion and the electrochemical behavior of Ni82.3cr7Fe3Si4.5B3.2 glassy alloy in HC1,H2So4,and H3Po4 acids were studied using AC and DC *** data reveal that the susceptibility to localized corrosion increases with increasing *** polarization curves reveal that the bulk glassy alloy is spontaneously passivated at all the investigated temperature in H2So4 and H3Po4 solutions.A localized corrosion effect in HCl solution is clearly *** apparent activation energies in the regions of Tafel,active,and passive,as well as the enthalpies and entropies of the dissolution process were determined and *** high apparent activation energy（Ea） value for H3Po4 solution in Tafel region is explained by the low aggressivity of Po4^3- ions.

关键词： nickel alloys corrosion temperature effect acidic environment passivation polarization