白云岩与砂岩致密储集体质量的差异性

白云岩与砂岩致密储集体质量参数为随机分布的连续谱系，孔隙结构、物理参数复杂多变，表征难度较大。基于铸体薄片、压汞、核磁共振、孔隙度和渗透率等测试技术，结合大量天然气勘探开发实际资料，采用统计分析对比方法，重点讨论了储层质量宏观与微观参数特征。结果表明，白云岩与砂岩致密储集体质量参数具有正态分布特征，是一种金字塔数据结构，常规储层比例一般为15%~20%，是砂岩或白云岩致密储层的“甜点”；致密砂岩储层微观孔隙发育，孔、喉连通性较好，分布比较均匀，储层孔、渗关系较好，表现为相对高孔和低渗；白云岩致密储层质量尽管具有孔、喉连通性差和孔、渗关系较差的不利因素，但也具有相对高渗、低束缚水饱和度、低排驱压力及裂缝网络发育等有利因素，天然气渗流能力较好，勘探开发潜力较大。我国发育碳酸盐岩沉积，应加强致密白云岩气藏成藏条件研究与勘探。     

Investigating measurements of fine particle (PM2.5) emissions from the cooking of meals and mitigating exposure using a cooker hood

There is growing awareness that indoor exposure to particulate matter with diameter ≤ 2.5 μm (PM_2.5) is associated with an increased risk of adverse health effects. Cooking is a key indoor source of PM_2.5 and an activity conducted daily in most homes. Population scale models can predict occupant exposures to PM_2.5, but these predictions are sensitive to the emission rates used. Reported emission rates are highly variable and are typically for the cooking of single ingredients and not full meals. Accordingly, there is a need to assess PM_2.5 emissions from the cooking of complete meals. Mean PM_2.5 emission rates and source strengths were measured for four complete meals. Temporal PM_2.5 concentrations and particle size distributions were recorded using an optical particle counter (OPC), and gravimetric sampling was used to determine calibration factors. Mean emission rates and source strengths varied between 0.54—3.7 mg/min and 15—68 mg, respectively, with 95% confidence. Using a cooker hood (apparent capture efficiency > 90%) and frying in non‐stick pans were found to significantly reduce emissions. OPC calibration factors varied between 1.5 and 5.0 showing that a single value cannot be used for all meals and that gravimetric sampling is necessary when measuring PM_2.5 concentrations in kitchens.     

2219铝合金搅拌摩擦焊和钨极保护焊焊接件残余应力的中子衍射研究

利用中子衍射法对2219铝合金搅拌摩擦焊（FSW）和钨极保护焊（TIG）焊接件开展了三维残余应力测量，并对残余应力分布规律进行了分析。结果表明：焊接件的纵向残余应力数值较大；FSW焊接件残余应力整体较TIG焊接件的小；FSW和TIG焊接件的残余拉应力最大值分别为101 MPa和174 MPa，FSW焊接件残余拉应力最大值较TIG焊接件的小；FSW残余拉应力最大值处于轴肩边缘，且前进侧峰值大于后退侧峰值；TIG焊接件残余拉应力最大值处于焊缝边缘。通过中子衍射实验获得的焊接件残余应力分布，将可用于焊接工艺的优化与焊接件的寿命预测。     

Two-level intelligent modeling method for the rate of penetration in complex geological drilling process

The rate of penetration (ROP) model is of great importance in achieving a high efficiency in the complex geological drilling process. In this paper, a novel two-level intelligent modeling method is proposed for the ROP considering the drilling characteristics of data incompleteness, couplings, and strong nonlinearities. Firstly, a piecewise cubic Hermite interpolation method is introduced to complete the lost drilling data. Then, a formation drillability (FD) fusion submodel is established by using Nadaboost extreme learning machine (Nadaboost-ELM) algorithm, and the mutual information method is used to obtain the parameters, strongly correlated with the ROP. Finally, a ROP submodel is established by a neural network with radial basis function optimized by the improved particle swarm optimization (RBFNN-IPSO). This two-level ROP model is applied to a real drilling process and the proposed method shows the best performance in ROP prediction as compared with conventional methods. The proposed ROP model provides the basis for intelligent optimization and control in the complex geological drilling process.     

Environmental and energy life cycle analyses of passenger vehicle systems using fossil fuel-derived hydrogen

Hydrogen energy utilization is expected due to its environmental and energy efficiencies. However, many issues remain to be solved in the social implementation of hydrogen energy through water electrolysis. This analyzes and compares the energy consumption and GHG emissions of fossil fuel-derived hydrogen and gasoline energy systems over their entire life cycle. The results demonstrate that for similar vehicle weights, the hydrogen energy system consumes 1.8 MJ/km less energy and emits 0.15 kg-CO 2 eq./km fewer GHG emissions than those of the gasoline energy system. Hydrogen derived from fossil fuels may contribute to future energy systems due to its stable energy supply and economic efficiency. Lowering the power source carbon content also improved the environmental and energy efficiencies of hydrogen energy derived from fossil fuels.     

Sustainable hydrogen roadmap: A holistic review and decision-making methodology for production,utilisation and exportation using Qatar as a case study

Hydrogen is seen as a promising and inevitable energy carrier in the transition towards a carbon-free energy era. This study reviews the potential for carbon-free hydrogen production, utilisation and exportation from the State of Qatar. The study aims to introduce a roadmap for current and future exploration of carbon-free hydrogen production and exportation from Qatar, for which an assessment of several available alternatives for the production of hydrogen in Qatar is performed. These alternatives include the use of natural gas as a feedstock for hydrogen production through steam methane reforming (SMR), solar integrated steam methane reforming with carbon capture, as well as the possibilities for hydrogen production from electrolysis using renewables and ammonia as another intermediate. The potential of each alternative is reviewed based on selected technical, economic and environmental criteria. The findings of this review study indicate that the production and exportation of blue ammonia currently present the best pathway for Qatar, while green hydrogen is expected to become as competitive as blue ammonia in the mid-future. It is widely accepted that as the technologies associated with clean hydrogen production improve, and the cost of renewable energy falls, green hydrogen will become quite competitive in the region.     

Syngas Methanation over Spray‐Granulated Ni/Al2O3 Catalyst in a Laboratory Transport‐Bed Reactor

Syngas methanation in a laboratory transport‐bed reactor has been performed. It was found that the CO conversion over the granular Ni/Al₂O₃ catalyst only slightly increased with the rise of aeration gas velocity for the recycling valve but severely decreased due to decreased gas residence time in the reactor. The effect of increasing the temperature of the recycled catalyst on the CO conversion at atmospheric pressure was also studied. Both the experimental temperature rise along the transport‐bed reactor and the estimated heat balance involving reactions verified the high heat‐transfer efficiency and its technical superiority for syngas methanation.     

Preparation and electrochemical characterization of Ti-based amorphous metallic glass with high strength

Ti-based amorphous metallic glasses have excellent mechanical, physical, and chemical properties, which is an important development direction and research hotspot of metal composite reinforcement. As a stable, simple, efficient, and large-scale preparation technology of metallic powders, the gas atomization process provides an effective way of preparing amorphous metallic glasses. In this study, the controllable fabrication of a Ti-based amorphous powder, with high efficiency, has been realized by using gas atomization. The scanning electron microscope, energy-dispersive spectrometer, and X-ray diffraction are used to analyze surface morphology, element distribution, and phase structure, respectively. A microhardness tester is used to measure the mechanical property. An electrochemical workstation is used to characterize corrosion behavior. The results show that as-prepared microparticles are more uniform and exhibit good amorphous characteristics. The mechanical test shows that the hardness of amorphous powder is significantly increased as compared with that before preparation, which has the prospect of being an important part of engineering reinforced materials. Further electrochemical measurement shows that the corrosion resistance of the as-prepared sample is also significantly improved. This study has laid a solid foundation for expanding applications of Ti-based metallic glasses, especially in heavy-duty and corrosive domains.     

Natural Gas Production

Current data on natural gas production, as well as a breakdown of production by country. Updated on a monthly basis.