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Petrography and stable isotopic variations in Dalmiapuram Formation of Cauvery Basin, south India: implication on OAE1d

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Chinese journal Of Geochemistry 2015年第3期34卷 447-458页

作者： j.Madhavaraju A.N.sial s.M.Hussain r.Nagarajan s.ramasamy Estación regional del Noroeste Instituto de GeologíaUniversidad Nacional Autónoma de México Nucleo de Estudos Geoquímicos e Laborató rio de Isótopos Estáveis (NEG - LABIsE) Departmento de GeologiaUniversidade Federal de Pernambuco Department of Geology University of Madras Department of Applied Geology School of Engineering and Science Curtin University

Petrography, carbon and oxygen isotopic study was carried out to interpret isotopic variations on the predominant carbonate sequence of the Dalmiapuram Formation of the Cauvery Basin, south India. The common petrographic types identified in the Dalmiapuram Formation range from wackestone to boundstone. The gray shale and limestone members show large variations in d13 C and d18 O values(Gray shale member: +1.44 to +2.40 %VPDB,-3.05 to-5.92 % VPDB, respectively; Limestone member:-6.07 to +2.93 % VPDB;-7.08 to-0.39 %VPDB; respectively). In the present study, the carbon and oxygen values are not correlated, which supports the fact that these limestones retain their primary isotopic signatures. In carbon isotope curve, one negative shift is identified in the gray shale member and a positive isotopic excursion is detected in the coral algal limestone(CAL).The observed positive isotopic excursion in the lower part of the CAL correlates with OAE1 d and suggests the global nature of the late Albian OAE1 d in the Cauvery Basin.

关键词：稳定同位素岩相学盆地印度蕴涵碳酸盐岩氧同位素偏移检测

rheological and stability analysis of cement pastes incorporating silica-based wastes

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Particuology 2024年第6期89卷 144-152页

作者： julia da rosa Martins janaíde Cavalcante rocha Dachamir Hotza Luciano senff Graduate Program in Materials science and Engineering(PPGMAT) Federal University of Santa Catarina(UFSC)Florianópolis88040-900SCBrazil Graduate Program in Civil Engineering(PPGEC) Federal University of Santa Catarina(UFSC)Florianópolis88040-900SCBrazil Graduate Program in Chemical Engineering(POsENQ) Federal University of Santa Catarina(UFSC)Florianópolis88040-900SCBrazil Department of Mobility Engineering Federal University of Santa Catarina(UFSC)Joinville89219-600SCBrazil

This study investigates the influence of waste characteristics,especially zeta potential,on the properties of cement pastes and *** focus is to evaluate the impact of the zeta potential of cement particles and waste materials on the sedimentation speed,rheology,and hardening time of stabilized cement *** Cement II F 40,retarder additive,silica,and fly ash were used in the *** pastes were prepared,and during the stabilization period,their rheological properties and pH were *** zeta potential and sedimentation speed of the cement and waste particles were measured at the pH that the pastes presented during the entire stabilization *** the stabilization period,the pastes were subjected to the hardening time *** zeta potential analyses revealed diverse values for the different powder types,with the cement particles exhibiting a zeta potential of−3.0 mV,the silica particles exhibiting−10.5 mV,and the fly ash particles exhibiting−20.3 *** influence of the high zeta potential modulus was observed on the sedimentation speed,with the solution containing fly ash exhibiting a speed of 40.01μm/s,whereas the solution containing only cement exhibited a speed of 99.38μm/*** the pastes,the results indicate that the presence of fly ash particles with a significantly negative zeta potential led to a 16%reduction in hardening time compared to particles with a lower modulus of zeta *** tests showed that the inclusion of fly ash particles prevented the formation of *** the zeta potential influenced agglomerate formation and hardening time,it was found to have no effect on yield stress or viscosity.

关键词： Wastes Zeta potential setting time rheometry

Ultrafine Grained HsLA steels for Cold Forming

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journal of Iron and steel research International 2010年第10期17卷 50-56页

作者： r González j O García M A Barbés M j Quintana L F Verdeja j I Verdeja school of Engineering Panamerican University ETsIMO Oviedo University

The industrial level production of ultrafine grained （or ultrafine ferrite） ferrous alloys was investigated through three examples of steels that complied with the EN 10149-2 Euronorm and were produced by advanced con- trolled hot rolling techniques. The steel samples were tension tested and chemically analyzed, and the microstructure was evaluated through quantitative metallographic techniques to determine parameters such as yield stress, amount of microalloying elements, strain hardening coefficient, grain size, and grain size distribution. These steels were micro- alloyed with Ti, Nb, and Mn with AsTM grain sizes of approximately 13--15. The careful control of chemical com- position and deformation during production, giving a specific attention to the deformation sequences, austenite non- reerystallization temperatures and allotropic transformations during cooling, are indispensable to obtain steels with an adequate strain hardening coefficient that allows cold working operations such as bending, stretching or drawing.

关键词： ultrafine steel metallography strain hardening Euronorm

structural Ultrafine Grained steels Obtained by Advanced Controlled rolling

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journal of Iron and steel research International 2013年第1期20卷 62-70页

作者： r González j O García M A Barbés M j Quintana L F Verdeja j I Verdeja school of Engineering Panamerican UniversityMexico City 03920Mexico E T s I M O Oviedo UniversityOviedo 33004Spain

steels with ultrafine grains （lower than 5 μm）, which usually known as ultrafine ferrite or ultrafine grained materials, are presently the object of intense research, because of the improvement in resistance and fracture toughness they may reach compared to conventional steels （with grain sizes above this value）. It is shown that the forenamed steels designated in the Euronorm EN 10149-2, which are manufactured by advanced techniques of controlled rolling and mainly used in automotive industry, have an ultrafine grain size in the range of 2.5 to 3.5 μm, and with elastic yield stresses higher than 400 MPa. Based on the Morrison-Miller criterion, it is shown that values of the strain-hardening coefficient lower than 0.08 would make the industrial application of these steels unfeasible.

关键词： ultrafine grained steel mechanical property manufacturability strain-hardening

A sensitivity analysis of millimeter wave characteristics of siC IMPATT diodes

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journal of semiconductors 2017年第6期38卷 58-65页

作者： s K swain j Pradhan G N Dash s r Pattanaik school of Physics sambalpur University Sambalpur Odisha 767019 India College of Engineering Bhubaneswar Bhubaneswar Odisha 751024 India National Institute of science and Technology Berhampur Odisha 761008 India

Ionization rate coefficients and saturation drift velocities for electrons and holes are the vital material parameters in determining the performance of an IMPATT *** have performed a sensitivity analysis of the millimeter wave characteristics of 4H-siC and 6H-siC IMPATT diodes with reference to the above mentioned material data and an operating frequency of 220 *** effect of a small variation in the ionization rate and drift velocity on the device characteristics like break down voltage,efficiency,noise measure and power output has been presented here.

关键词： IMPATT siC ionization rate saturation drift velocity, millimeter wave

strip Casting of High Performance structural Alloys

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journal of rare Earths 2004年第z2期22卷 78-84页

作者： s s Park j G Lee Nack j Kim Center for Advanced Aerospace Materials Pohang University of Science and TechnologyPohang 790-784Korea Center for Advanced Aerospace MaterialsPohang University of Science and TechnologyPohang 790-784Korea Center for Advanced Aerospace MaterialsPohang University of Science and TechnologyPohang 790-784Korea

There exists a great need for the development of high performance alloys due to increasing demands for energy conservation and environmental protection. Application of strip casting shows a strong potential for the improvement of properties of existing alloys and also for the development of novel alloy systems with superior properties. The present paper reviews our Center's activities in the development of high performance alloys by strip casting. Examples include (1) Al alloys, (2) wrought Mg alloys, and (3) bulk metallic glass (BMG) alloys.

关键词： strip casting 6061 Al alloy AZ Mg alloy bulk metallic glass (BMG) alloy dispersion hardening

Acetosolv delignification of marabou (Dichrostachys cinerea) wood with and without acid prehydrolysis

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Forestry studies in China 2011年第1期13卷 64-70页

作者： Venkata Prabhakar sOUDHAM Dani rODrIGUEZ George j M rocha Mohammad j TAHErZADEH Carlos MArTIN Bioresource Technology Group Department of Chemistry and Chemical EngineeringUniversity of Matanzas school of Engineering University of Bors Department of Biotechnology Lorena School of EngineeringUniversity of So Paulo

The chemical composition of marabou（Dichrostachys cinerea） wood and its treatment with acetic acid were *** different treatment approaches,direct acetosolv and combined acid prehydrolysis/acetosolv,were *** effects of acetic acid concentration（50%,70% and 90%） and temperature（normal boiling temperature and 121°C） on yield of solids,solubilization of lignin and hemicelluloses and recovery of cellulose were evaluated for both *** solubilization of marabou components was observed in the direct acetosolv treatment at 121°C,especially at the highest acetic acid concentration,where around 84.8% of lignin and 78% of hemicelluloses were *** the material was subjected to acid prehydrolysis prior to acetosolv treatment,lignin solubilization was improved,especially at low acetic acid *** 80% of the solubilized lignin was recovered from the liquors in the direct acetosolv treatment,but the recovery was lower in the combined *** was well preserved in all the treatment schemes.

关键词： Dichrostachys cinerea delignification acetosolv acid hydrolysis

The analysis of composite laminated beams using a 2D interpolating meshless technique

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Acta Mechanica sinica 2018年第1期34卷 99-116页

作者： s.H.M.sadek j.Belinha M.P.L.Parente r.M.Natal jorge j.M.A.César de sá A.j.M.Ferreira Department of Mechanical Engineering Faculty of EngineeringUniversity of Porto Institute of Mechanical Engineering and Industrial Management University of Porto

Laminated composite materials are widely implemented in several engineering constructions. For its relative light weight, these materials are suitable for aerospace, military, marine, and automotive structural applications. To obtain safe and economical structures, the modelling analysis accuracy is highly relevant. since meshless methods in the recent years achieved a remarkable progress in computational mechanics, the present work uses one of the most flexible and stable interpolation meshless technique available in the literature—the radial Point Interpolation Method(rPIM).Here, a 2 D approach is considered to numerically analyse composite laminated beams. Both the meshless formulation and the equilibrium equations ruling the studied physical phenomenon are presented with detail. several benchmark beam examples are studied and the results are compared with exact solutions available in the literature and the results obtained from a commercial finite element software. The results show the efficiency and accuracy of the proposed numeric technique.

关键词： radial point interpolators rPIM Laminated beam Meshless method

Two distinct Paleozoic metamorphic events in the Tarim-North China Collage

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National science review 2023年第2期10卷 7-8页

作者： jérémie soldner state Key Laboratory of Isotope Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences CAs Center for Excellence in Deep Earth science

The Central Asian Or ogenic Belt(CAOB) [1],which includes the Altaids in Central and Northern Asia [2],is the largest accretionary orogen formed during the subduction of the Paleo-Asian Ocean and the Panthalassa Ocean in the period of the Late Proterozoic to Late Paleozoic [3].Closure of the Paleo-Asian Ocean is attributed to the northward drift of the North China and Tarim cratons leading to the massive shortening and oroclinal buckling of the CAOB accretionary system in the Permian [4].

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