Middle Eocene terrestrial paleoweathering and climate evolution in the midlatitude Bohai Bay Basin of eastern China

The middle Eocene climatic optimum(MECO,ca.-42 Ma)is a key time period for understanding Cenozoic cooling of the global climate.Still,midlatitude terrestrial records of climate evolution during MEcO epoch are rare.In this study,continuous high-resolution record of shale sediments in mid-Eocene Shahejie Formation(MES shales)in the Bohai Bay Basin were performed with major-element and wavelet analysis.The midlatitude paleoweathering and paleoclimatic evolution during MEcO epoch were analyzed in this study.The MES shales experienced weak-moderate paleoweathering under a subtropical monsoon paleoclimate with mean annual temperature of 8.3-12.9℃ and mean annual precipitation of 685-1100 mm/yr.The MES shales record a mixed provenance involving intermediate igneous rocks,and low compositional maturity.The nutrient-rich environment led to enrichment in organic matter in the MES shales.Wavelet analysis revealed good periodicity about the paleoclimate and weathering during MECO epoch.In the stage I of MES shales depositional process,the paleolake was high in nutrients,and the MES shales experienced high chemical weathering due to a relatively warmer and more humid climate.In contrast,the climate in stage II was relatively cold and dry,and the maturity of the MES shales was relatively high during this stage,suggesting a relatively stable tectonic background.This work provides more terrestrial records of MEco epoch for midlatitude region,and is benefit for better understanding of the palaeoenvironment when MES shales formed.The implication of organic matters enrichment in this study is meaningful for the shale oil/gas exploration in Nanpu Sag.

Carbon Reduction Programs and Key Technologies in Global Steel Industry

Greenhouse gases, particularly the carbon dioxide, cause global warming and extreme weather, which has become a serious threat to human beings. The steel industry creates enormous amounts of carbon emission and has tremendous potential in carbon reduction. Considering the consistently increasing demand of iron and steel, to obtain significant carbon reduction by reducing the steel production is not practical, thus the development and implementa- tion of carbon reduction programs and technologies is important for the steel industry. Despite the significant poten- tial of carbon reduction in the steel industry, ironmaking and steelmaking processes are complex. Therefore, resear- ches and developments for the carbon reduction must focus on key processes. Here, key processes and technologies adopted in ULCOS program in EU, COURSE 50 program in Japan, POSCO program in South Korea, AISI pro- grams in US and other carbon reduction programs are summarized and evaluated, and feasible suggestions for carbon reduction in developing countries are presented. If effective measures can be referred to and taken in developing coun- tries, global carbon emission can be greatly reduced.

A volume of fluid simulation of the steady deformation and the drag of a single droplet in a flowing gas

A method is proposed to investigate the steady deformation and the drag of a single droplet in a flowing gas at a high Reynolds number.The volume of fluid(VOF)method is used to model the droplet surface structure.The direct numerical simulation(DNS)method is used to model the gas flow field.In order to avoid the effect of the droplet acceleration on the drag and reduce the computation cost,a body force is added to the droplet to make it fixed at a constant position.The body force is determined by using the Newton iteration procedure.The simulated droplet aspect ratio and the drag coefficient agree well with the published experimental data.Meanwhile,the sources of the drag are analyzed and the effect of the Reynolds number and the Weber numbers on the droplet deformation and the drag are studied.The drag mainly comes from the pressure difference between the droplet-leading zone and the trailing zone,and the turbulence wake would increase the drag.

Dilatometric Analysis of Irreversible Volume Change during Phase Transformation in Pure Iron

One assumption underlying the conventional dilatometric analysis based on the lever rule is that the volume of the specimen changes isotropically during phase transformation,which conflicts with the irreversible length change shown in actual measurements.The contribution of this irreversible effect to the dilation data of pure iron upon heating and cooling was respectively quantified via conversion equations based on lattice parameters.A model considering the elastic strain and creep deformation was established for both the interpretation of the irreversible volume change and the discrepancy between the results measured by a dilatometer and a micrometer.