Adsorbed and free gas occurrence characteristics and controlling factors of deep shales in the southern Sichuan Basin,China

Deep shale gas(3500-4500 m)will be the important succeeding field for the growth of shale gas production in China.Under the condition of high temperature and high pressure in deep shale gas reservoirs,its gas occurrence characteristics are markedly different from those of medium and shallow layers.To elucidate the gas occurrence characteristics and controlling factors of deep shales in the Wufeng-Longmaxi Formation,methane adsorption,low-temperature N2,and cO2 adsorption experi-ments were conducted.The results show that in deep shales,the mesopores provide approximately 75%of the total specific surface area(SA)and 90%of the total pore volume(PV).Based on two hypotheses and comparing the theoretical and actual adsorption capacity,it is speculated that methane is adsorbed in deep shale in the form of micropore filling,and free gas is mainly stored in the mesopores.Correlation analysis demonstrated that ToC is the key material constraint for the adsorption capacity of deep shale,and micropore SSA is the key spatial constraint.Other minerals and mesopore parameters have limited effect on the amount of adsorbed gas.Moreover,the free gas content ranges from 2.72 m^(3)/t to 6.20 m^(3)/t,with an average value of 4.60 m^(3)/t,and the free gas content ratio is approximately 58%,suggesting that the deep shale gas reservoirs are dominated by free gas.This ratio may also increase to approximately 70%when considering the formation temperature effect on adsorbed gas.Gas density,porosity,and gas saturation are the main controlling factors of free gas content,resulting in significantly larger free gas content in deep shale than in shallower formations.

Electrodeposition of Zn(O,S)(zinc oxysulfide)thin films:Exploiting its thermodynamic and kinetic processes with incorporation of tartaric acid

Zn（O,S）（zinc oxysulfide） is an important chalcogenide material recently reported to be potentially applied as electrode buffers in thin film solar cells. Both vacuum and solution approaches have enabled the fabrication of Zn（O,S） films. However they either require extreme conditions and high energy consumption for synthesis, or suffer from lack of controllability mainly due to the thermodynamic and kinetic distinction between Zn O and Zn S during film growth. Here we demonstrated an effective electrodeposition route to obtain high-quality Zn（O,S） thin films in a controllable manner. Importantly, tartaric acid was employed as a secondary complexing agent in the electrolyte to improve the film morphology, as well as to adjust other key properties such as composition and absorption. To elucidate the vital role that tartaric acid played, thermodynamic and kinetic processes of electrodeposition was investigated and discussed in detail. The accumulative contribution has shed light on further exploit of Zn（O,S） with tunable properties and optimization of the corresponding electrodeposition process, for the application in thin film solar cells.

Dissolutive wetting process and interfacial characteristic of molten Sn–17Bi–0.5Cu alloy on copper substrate

The reactive spreading processes of Sn–17Bi–0.5Cu melt alloy on Cu substrate were studied by sessile drop method in the temperature range of 523–673 K.Dynamic contact angles between the solder and Cu substrate at different times were recorded with high-resolution CCD digital video.The smallest contact angle was observed at623 and 673 K.Ultimate spreading radius does not increase monotonously with the temperature increasing.These can be attributed to the strong dissolution of Cu substrate into the liquid solder,which hinders the solder from spreading.Triple line area configuration of the Sn–17Bi–0.5Cu/Cu system was discussed by the description of the equilibrium state.The calculated results based on experiments of the tension balances along each of the three interfaces show good agreement with theoretical analysis.Intermetallic compounds at the Sn–17Bi–0.5Cu/Cu interface are identified as Cu6Sn5adjacent to the solder and Cu3Sn adjacent to the Cu substrate,respectively.These results are of practical interest for composite lead-free solders’preparations and joining of Sn–17Bi–0.5Cu to Cu substrate.

Influences of initial velocity,diameter and Reynolds number on a circular turbulent air/air jet

This paper assesses the suitability of the inflow Reynolds number defined by Reo -- UoD/v （here Uo and D are respectively the initial jet velocity and diameter while v is kinematic viscosity） for a round air/air jet. Specifically an experimental investigation is performed for the influences of Uo, D and Reo on the mean-velocity decay and spread coefficients （Ku, Kr） in the far field of a circular air jet into air from a smoothly contracting nozzle. Present measurements agree well with those previously obtained under similar inflow conditions. The relations Ku ∝ Uo and Kr ∝ 1/Uo for Uo 〈 5 m/s appear to work, while each coefficient approaches asymptotically to a constant for Uo 〉 6 m/s, regardless of the magnitudes of Reo and D. It is revealed that Reo may not be an appropriate dimensionless parameter to characterize the entire flow of a free air/air jet. This paper is the first paper that has challenged the suitability of Reo for turbulent free jets.

Diagnostic of Flooding and Hysteresis Phenomena for Proton Exchange Membrane Fuel Cell using Cyclo-Voltammogram Simulation

Porous electrodes with three-phase reaction in low temperature fuel cells have attracted much attention by their flooding phenomena. In order to have a better understanding of the flooding phenomena inside electrode, it is important to evaluate various discharge conditions of the flooded electrodes. A model of flooded porous electrode under the influence of potential sweep was developed to evaluate the flooding conditions in-situ. The hysteresis of current density vs. time was observed at high sweep rates （1 O0 mV.sl）. It was not observed at low sweep rate （0.1 mV-s~）. In this study, these characteristics of flooding and hysteresis conditions were found to be markedly dependent on the potential scan rate. These dynamic behaviors are interpreted in terms of water saturation response, velocity of water movement, and evaporation rate of water.

Investigation of Self-Diffusion and Structure in Calcium Aluminosilicate Slags by Molecular Dynamics Simulation

Molecular dynamics simulation is applied to investigate the mechanism and variation of self-diffusion in calcium aluminosilicate slags. The self-diffusion coefficients are calculated for eleven slag compositions with varying Al2O3/SiO2 ratios at a fixed CaO content. In practice, the results of the study are relevant to the significant changes in transport phenomenon caused by the changes in chemical composition during continuous casting of steels containing high amounts of dissolved aluminum. The cooperative movement between O atoms and network formers is discussed since [AlO4] and [SiO4] tetrahedra are the elementary structural units in the CaO-Al2O3-SiO2 (CAS) slag system. The diffusivities for four atomic types are affected by the degree of polymerization (DOP) of slag network characterized by the proportions of non-bridging oxygen (NBO) and Qn species in the system. On the other hand, a sudden increase in 5-coordinated Al as network modifiers in high alumina regions slightly increases the self-diffusion coefficient for Al. As another structural defect, oxygen tricluster plays an important role in the behavior of self-diffusion for O atoms, while the diffusivity for Ca is deeply influenced by its bonding and coordinating conditions.

Thermodynamic studies on gas-based reduction of vanadium titano-magnetite pellets

Numerous studies have focused on the reduction thermodynamics of ordinary iron ore;by contrast, the literature contains few thermodynamic studies on the gas-based reduction of vanadium titano-magnetite (VTM) in mixed atmospheres of H2, CO, H2O, CO2, and N2. In this paper, thermodynamic studies on the reduction of oxidized VTM pellets were systematically conducted in an atmosphere of a C–H–O system as a reducing agent. The results indicate that VTM of an equivalent valence state is more difficult to reduce than ordinary iron ore. A reduction equilibrium diagram using the C–H–O system as a reducing agent was obtained;it clearly describes the reduction process. Experiments were performed to investigate the effects of the reduction temperature, the gas composition, and two types of iron ores on the reduction of oxidized VTM pellets. The results show that the final reduction degree increases with increasing reduction temperature, increasing molar ratio of H2/(H2 + CO), and decreasing H2O, CO2, and N2 contents. In addition, the reduction processes under various conditions are discussed. All of the results of the reduction experiments are consistent with those of theoretical thermodynamic analysis. This study is expected to provide valuable thermodynamic theory on the industrial applications of VTM.

Reduction mechanism of natural ilmenite with graphite

Reduction of Bama ilmenite concentrate containing 49.78% TiO2 and 27.96% total Fe by graphite was studied using thermogravimetric analysis system under argon gas ambient from 850 to 1 400 ℃. The reduction degree of Bama ilmenite is enhanced with increasing temperature and the molar ratio of carbon to oxygen, and the reaction rate varies with temperature and reduction time simultaneously. The phase transformation, chemical composition, microstructure and morphology of reduced samples were investigated by using X-ray diffractometry, scanning electron microscopy, and energy disperse spectroscopy, respectively. The high content of impurities in Bama ilmenite evidently bates the reduction of ilmenite. Forming the enrichment zone of manganese prevents complete reduction of Fe2+. The reduction products are mostly reduced iron, rutile, reduced rutiles, Ti3O5 and pseudobrookite solid solution. The reduction kinetics was also discussed. The results show that the reduction temperature is a key factor to control reaction rate.

Crustal growth history of the Korean Peninsula: Constraints from detrital zircon ages in modern river sediments

U-Pb analyses were carried out on detrital zircon grains from major river-mouth sediments draining South Korea to infer provenance characteristics and the crustal growth history of the southern Korean Peninsula, using a laser ablation inductively coupled plasma mass spectrometer（LA-ICP-MS）. The Korean Peninsula is located in the East Asian continental margin and mainly comprises three Precambrian massifs and two metamorphic belts in between them. We obtained 515 concordant to slightly discordant zircon ages ranging from ca. 3566 to ca. 48 Ma. Regardless of river-mouth location, predominance of Mesozoic（249e79 Ma） and Paleoproterozoic（2491e1691 Ma） ages with subordinate Archean ages indicates that the zircon ages reflect present exposures of plutonic/metamorphic rocks in the drainage basins of the South Korean rivers and the crustal growth of the southern Korean Peninsula was focused in these two periods. Comparison of detrital zircon-age data between the North and South Korean river sediments reveals that the Paleoproterozoic zircon age distributions of both regions are nearly identical,while the Neoproterozoice Paleozoic ages exist and the Mesozoic ages are dominant in southern Korean Peninsula. This result suggests that Precambrian terrains in Korea record the similar pre-Mesozoic magmatic history and that the influence of Mesozoic magmatism was mainly focused in South Korea.

Identification of reversible insertion-type lithium storage reaction of manganese oxide with long cycle lifespan

Recently,MnO2 has gained attention as an electrode material because of its very high theoretical capacity and abundant availability.However,the very high volumetric change caused by its conversion-type reaction results in bad reversibility of charge-discharge.In this study,δ-MnO2 of thickness 8 nm anchored on the surface of carbon nanotubes(CNT)by Mn-O-C chemical bonding is synthesized via a facile hydrothermal method.Numerous ex-situ characterizations of the lithium storage process were performed.Furthermore,density functional theory(DFT)calculations indicated thatδ-MnO2(012)thermodynamically prefers bonding with CNTs.Moreover,the interfacial interaction reinforces the connection of Mn-O and reduces the bond strength of Li-O in lithiated MnO2,which could facilitate an intercalation-type lithium storage reaction.Consequently,the as-synthesizedδ-MnO2 retains an excellent reversible capacity of 577.5 mAh g-1 in 1000 cycles at a high rate of 2 A g-1 between 0.1 V and 3.0 V.The results of this study demonstrate the possibility of employing the cost-effective transition metal oxides as intercalation lithium storage dominant electrodes for advanced rechargeable batteries.

Composition of off-gas produced by combined fluidized bed chlorination for preparation of TiCl_4

The effects of carbon/slag molar ratio, chloride amount and temperature on equilibrium molar ratio (REq) of CO to CO2 for off-gas produced by carbochlorination of titanium slag were firstly investigated by thermodynamic calculation of equilibrium components of off-gas. The experimental CO/CO2 molar ratio (REx) was then obtained to be 0.2-0.3 by the carbochlorination experiment using a novel combined fluidized bed as chlorination reactor. To further investigate the reaction effect of the novel process mentioned above, REx, REq and corresponding reference data (RRe) were compared. The results indicate that REx is similar to RRe (0.5-1.2) but different from REq (≥4.3), which is consistent with anticipation of REx for the novel combined fluidized bed. The difference between REx and corresponding REq is mainly attributed to short retention time (about 1 s) of materials in combined fluidized bed and carbochlorination of oxide impurities contained in titanium slag, such as CaO, MgO and SiO2.

Radiation synthesis of polymer/clay nanocomposite hydrogels with high mechanical strength

Poor mechanical properties of PNIPAAm hydrogels have limited their applications. Nanocomposite hydrogels(NC gels) which incorporate inorganic clay possess high mechanical strength and other desirable properties.In this paper, we report a facile approach to synthesize NC gels using radiation technique. With exfoliated clay sheets acting as crosslinkers, N-isopropylacrylamide monomers are polymerized and crosslinked to form NC gels under γ-irradiation at room temperature. Apart from regular swelling behavior and interesting performance in thermo sensitivity, the radiation synthesized NC gel(RNC gel) has good optical transparency, high strength and flexibility. Through Micro-FTIR, XPS and TG analyses, a particular chemically crosslinked organic/inorganic network was identified in the RNC gel.

Wetting between molten iron and prereduced ilmenite with carbon

An interfacial study between molten iron and the prereduced ilmenite with carbon was conducted at different melting temperatures by the sessile droplet method.The wetting characteristics between molten iron and the prereduced ilmenites with carbon were investigated by measuring contact angle of the droplet of molten iron on the prereduced ilmenite substrate.The images of the interface were also examined by the optical microscope and SEM equipped with EDS.The volume of molten iron increased with the melting temperature increasing when titania or high-content titania slag was used as the substrate.The contact angle decreased with the melting temperature increasing and it was independent on time at constant temperature.The contact angle was positively correlated with the reduction degree of the ilmenite,but the work of adhesion was negatively correlated with it.Higher smelting temperature was beneficial to the separation of iron and Ti oxides.The permeability of molten iron into the prereduced ilmenite with carbon was more obvious with reduction degree increasing owing to the high porosity of prereduced ilmenite.

Nanoparticle stabilized emulsion with surface solidification for profile control in porous media

Profile control is utilized to redirect the injection water to low permeability region where a large amount of crude oil lies.Performed gel particles are the commonly used agent for redistributing water by blocking the pores in high permeability region.But the capability of deep penetration of performed gel particles is poor.Here,we formulate nanoparticle stabilized emulsion(NSE).The stability and the effect of NSE on the fluid redirection in a three-dimensional porous medium were investigated.By usingμ-PIV(particle image velocimetry),it was found that the velocity gradient of continuous fluid close to the nanoparticle stabilized droplets is much higher than that close to surfactant stabilized droplets.NSE behaves as solid particle in preferential seepage channels,which will decrease effectively the permeability,thereby redirecting the subsequent injection water.Furthermore,NSE shows high stability compared with emulsion stabilized by surfactant in static and dynamic tests.In addition,water flooding tests also confirm that the NSE can significantly reduce the permeability of porous media and redirect the fluid flow.Our results demonstrate NSE owns high potential to act as profile control agent in deep formation.

Green energy for green future

Glories in the history of civilization are built on the burning of non-renewable fossil fuels.In the last fifty years,the global population increased over twice,from 3.0 billion in 1960 to 7.3 billion in2015,and the global GDP increased over 50 times,from 1.4 trillion US$in 1960 to 74.2 trillion US$in 2015.Along with the evolution of humanity is the skyrocketing fossil fuel consumptions,from3514.2 millions of tonnes of oil equivalent/year(mtoe/y)in 1965 to11,306.4 mtoe/y in 2015,as well as the irreversible climate

Purang Ultramafic Complex and Their Geological Origin, Southwest Tibet

Neoproterozoic ophiolitic Serpentinites are common in the Arabian-Nubian Shield （ANS） of the Eastern Desert （ED） of Egypt, which were formed in arc stage in different tectonic setting. Thus they might subject to exchange with the crustal material derived from recycling subducting oceanic lithosphere. This caused metasomatism enriching the rocks in incompatible elements and forming non- residual minerals. Herein,

Element migration and phase distribution characteristics during crystallization of rare earth phase in rare earth slag

The crystallization experiment of molten rare earth(RE)slag under different cooling rates was carried out.The characteristics of element migration and phase distribution during RE phase crystallization were studied by using different equipment.The experimental results show that there are two RE phases in the RE slag,namely(Ca,Ce,La)_(5)(SiO_(4))6F and(Ca,Ce,La,Mg)_(3)(Ti,Al,Nb)_(2)O_(7).During the cooling crystallization process of molten RE slag,Ca and P elements in the RE phase of(Ca,Ce,La)_(5)(SiO_(4))_(6)F migrate from inside to outside,and finally gather at the outer edge of the phase to form phase Ca_(3)(PO4)2.The RE phase(Ca,Ce,La)_(5)(SiO_(4))_(6)F is distributed inside the furnace-cooled slag,and the RE phase(Ca,Ce,-La,Mg)_(3)(Ti,AI,Nb)_(2)O_(7)is distributed in the surface layer of the furnace-cooled slag.And based on the phase distribution characteristics,the central hollowing method is proposed to realize the preliminary enrichment of valuable elements Ti,Nb and RE in RE slag.

Energy and exergy performance investigation of transcritical CO_2-based Rankine cycle powered by solar energy

A comprehensive performance evaluation of a solar assisted transcritical CO2-based Rankine cycle system is made with exergy analysis method. The actual thermal data taken from the all-day experiment of the system are utilized to determine energy transfer and the exergy destructions in each component of the system. In addition, a hypothetical carbon dioxide expansion turbine is introduced, then two thermodynamic models for solar transcritical carbon dioxide Rankine cycles with a throttling valve (experiment) and with an expansion turbine have been established with exergy analysis method. The obtained results clearly show that solar collector contributes the largest share to system irreversibility and entropy generation in the all-day working state, and the exergy improvement potential of solar collector is the maximum in the working state. So this component should be the optimization design focus to improve system exergy effectiveness. For the cycle with the turbine, the energy efficiency and the entropy generation are not much higher than the cycle with throttling valve, but the exergy efficiency of the cycle with turbine is twice of the cycle with throttling valve. It provides more guidance when the transcritical CO2-based Rankine system is in a large-scale solar application.

Iterative learning-based many-objective history matching using deep neural network with stacked autoencoder

This paper presents an innovative data-integration that uses an iterative-learning method,a deep neural network(DNN)coupled with a stacked autoencoder(SAE)to solve issues encountered with many-objective history matching.The proposed method consists of a DNN-based inverse model with SAE-encoded static data and iterative updates of supervised-learning data are based on distance-based clustering schemes.DNN functions as an inverse model and results in encoded flattened data,while SAE,as a pre-trained neural network,successfully reduces dimensionality and reliably reconstructs geomodels.The iterative-learning method can improve the training data for DNN by showing the error reduction achieved with each iteration step.The proposed workflow shows the small mean absolute percentage error below 4%for all objective functions,while a typical multi-objective evolutionary algorithm fails to significantly reduce the initial population uncertainty.Iterative learning-based manyobjective history matching estimates the trends in water cuts that are not reliably included in dynamicdata matching.This confirms the proposed workflow constructs more plausible geo-models.The workflow would be a reliable alternative to overcome the less-convergent Pareto-based multi-objective evolutionary algorithm in the presence of geological uncertainty and varying objective functions.