The effect of operating and design parameter on bubble column performance: The LOPROX case study

It is known that the performances of multi-phase reactors depend on the operating parameters (the temperature and the pressure of the system), the phase properties, and the design parameters (the aspect ratio (AR), the bubble column diameter, and the gas sparger design). Hence, the precise design and the correct operation of multi-phase reactors depends on the understanding and prediction of the fluid dynamics parameters. This paper contributes to the existing discussion on the effect of operating and design parameter on multi-phase reactors and, in particular, it considers an industrial process (e.g., the LOPROX (low pressure oxidation) case study, which is typical example of two-phase bubble columns). Based on a previously-validated set of correlations, the influence of operating and design parameter on system performances is studied and critically analyzed. First, we studied the effects of the design parameter on the liquid–gas interfacial area, by keeping constant the fluid physical–chemical properties as well as the operating conditions; subsequently, we discussed for a fixed system design, the influence of the liquid phase properties and the operating pressure. In conclusion, this paper is intended to provide guidelines for the design and scale-up of multi-phase reactors.     

钢筋混凝土拆除爆破炮孔装药量的确定

本文从分析钢筋混凝土爆破破坏形态出发,对钢筋混凝土的配筋情况,如强度、配筋网规格、钢筋层数等对拆除爆破的影响作了量化处理,在前人的基础上大胆提出了钢筋混凝土加强抛掷爆破的炮孔装药量计算公式,并在实际工程中得到了验证。     

负压吸引技术应用于大面积烧伤患者围术期的效果探究

目的:探究环磷酸腺苷联合负压吸引技术应用于大面积烧伤患者围术期的效果及肾保护作用探究。方法:选择2018年12月到2020年12月于医院治疗的120例大面积烧伤患者为研究对象,以随机数字表法对患者分组,60例患者为研究组,60例患者为对照组,对照组给予负压吸引技术治疗,研究组在此基础上给予环磷酸腺苷治疗,治疗前、后测定两组患者干扰素-γ(IFN-γ)、白细胞介素-2(IL-2)、白细胞介素-10(IL-0)、白细胞介素-6(IL-6)、可溶性血管细胞粘附分子-1(sVCAM-1)、一氧化氮(NO)、内皮素(ET-1)、血管内皮生长因子(VEGF)、胱抑素C(Cys-C)、肌酐(Scr)、血尿素氮(BUN)、肾损伤分子-1(KIM-1)水平,记录两组患者手术时间、麻醉苏醒时间、住院时间。结果:研究组IFN-γ、IL-6水平低于对照组(P<0.05),研究组患者IL-2、IL-10水平高于对照组(P<0.05),研究组NO、VEGF水平高于对照组(P<0.05),研究组患者sVCAM-1、ET-1水平低于对照组(P<0.05),研究组患者Cys-C、Scr、BUN、KIM-1水平低于对照组(P<0.05),研究组手术时间低于对照组(P>0.05),研究组麻醉苏醒时间、住院时间低于对照组(P<0.05)。结论:环磷酸腺苷联合负压吸引技术应用于大面积烧伤围术期患者,可降低患者IFN-γ、IL-6水平,提升患者IL-2、IL-10水平,抑制患者炎症,改善患者血管内皮功能,降低患者Cys-C、Scr、BUN、KIM-1水平,减少患者肾功能损伤,减少患者麻醉苏醒时间及住院时间。     

国内外主要粟类作物的种植、研究及产业化概况（网络首发、推荐阅读）

粟类作物是一类籽粒小、抗旱、耐贫瘠的一年生作物的统称，多种植和消费在亚洲和非洲的发展中国家，我国栽培面积比较大的是谷子和糜子。与种植和消费情况不同，亚洲、欧洲和美洲相对发达国家的政府更重视粟类作物的科学研究及其科研投入。我国国家自然科学基金资助发表的粟类研究论文居世界之首，欧洲委员会、英国研究与创新署、美国国家科学基金会资助的粟类研究论文数量排名紧跟其后。梳理了近5年发表的粟类科研论文，印度最多，其次是我国和美国。基于粟类作物富含膳食纤维、蛋白质、矿物质、多酚等，其具有多方面的健康功效，因此粟类的食品科学技术和植物科学成为最热的研究领域。最后阐述了国内外传统的和工业化的粟类产品情况。     

A lattice Boltzmann exploration of two-phase displacement in 2D porous media under various pressure boundary conditions

While experimental designs developed in recent decades have contributed to research on dynamic nonequilibrium effects in transient two-phase flow in porous media, this problem has been seldom investigated using direct numerical simulation (DNS). Only a few studies have sought to numerically solve Navier–Stokes equations with level-set (LS) or volume-of-fluid (VoF) methods, each of which has constraints in terms of meniscus dynamics for various flow velocities in the control volume (CV) domain. The Shan–Chen multiphase multicomponent lattice Boltzmann method (SC-LBM) has a fundamental mechanism to separate immiscible fluid phases in the density domain without these limitations. Therefore, this study applied it to explore two-phase displacement in a single representative elementary volume (REV) of two-dimensional (2D) porous media. As a continuation of a previous investigation into one-step inflow/outflow in 2D porous media, this work seeks to identify dynamic nonequilibrium effects on capillary pressure–saturation relationship (P_c–S) for quasi-steady-state flow and multistep inflow/outflow under various pressure boundary conditions. The simulation outcomes show that P_c, S and specific interfacial area (a_nw) had multistep-wise dynamic effects corresponding to the multistep-wise pressure boundary conditions. With finer adjustments to the increase in pressure over more steps, dynamic nonequilibrium effects were significantly alleviated and even finally disappeared to achieve quasi-steady-state inflow/outflow conditions. Furthermore, triangular wave-formed pressure boundary conditions were applied in different periods to investigate dynamic nonequilibrium effects for hysteretical P_c–S. The results showed overshoot and undershoot of P_c to S in loops of the nonequilibrium hysteresis. In addition, the flow regimes of multistep-wise dynamic effects were analyzed in terms of Reynolds and capillary numbers (Re and Ca). The analysis of REV-scale flow regimes showed higher Re (1 < Re < 10) for more significant dynamic nonequilibrium effects. This indicates that inertia is critical for transient two-phase flow in porous media under dynamic nonequilibrium conditions.     

A columnar regular-porous stainless steel reaction support with high superficial area for hydrogen production

To improve hydrogen production (HP) performance of regular-porous structure (RPS), a columnar RPS with small specific surface area and high superficial area is developed. A numerical simulation model of regular-porous stainless steel structure (RPSSS) is established. Subsequently, heat transfer performance, pressure loss, temperature, methanol concentration, H₂ concentration distributions and HP performance of the columnar RPSSS with small specific surface area and high superficial area and the body-centered cubic RPSSS with high specific surface area and small superficial area are compared. Then, temperature, methanol concentration, H₂ concentration distributions and HP performance of axial and longitudinal size-enlarged columnar RPSSSs are studied. The results show that compared to the body-centered cubic RPSSS, the columnar RPSSS has higher methanol conversion, larger H₂ flow rate and higher CO selectivity. Especially in the condition of 300 °C wall temperature and 12 mL/h methanol-water mixture injection rate (MWMIR), the methanol conversion, H₂ flow rate and CO selectivity of the columnar RPSSS are increased by 12.3%, 9.24% and 30%, respectively, indicating that the superficial area of RPSSS is more important for its HP performance compared to its specific surface area. Compared to the longitudinal size-enlarged columnar RPSSS, the axial size-enlarged columnar RPSSS has higher methanol conversion, larger H₂ flow rate and higher CO selectivity. This research work provides a new method for the optimization of hydrogen production reaction support (HPRS).     

A modified Kozeny–Carman equation for predicting saturated hydraulic conductivity of compacted bentonite in confined condition

Kozeny–Carman (KC) equation is a well-known relation between hydraulic conductivity and pore properties in porous material. The applications of KC equation to predicting saturated hydraulic conductivities of sands and non-expansive soils are well documented. However, KC equation is incapable of predicting saturated hydraulic conductivity of expansive soil (e.g. bentonite) well. Based on a new dual-pore system, this study modified KC equation for improving the prediction of saturated hydraulic conductivities of bentonites. In this study, an assumption that inter-layer space (micropore) has limited effect on fluid flow performance of compacted bentonite was adopted. The critical parameters including total porosity and total tortuosity in conventional KC equation were replaced by macroporosity and tortuosity of macropore, respectively. Macroporosity and microporosity were calculated by basal spacing of compacted bentonite, which was estimated by assuming that specific surface area is changeable during saturation process. A comprehensive comparison of bentonite's saturated hydraulic conductivity predictions, including modified KC equation proposed in this study, conventional KC equation, and prediction method based on diffuse double layer (DDL) theory, was carried out. It was found that the predicted saturated hydraulic conductivity of bentonites calculated using modified KC equation fitted the experimental data better than others to a certain extent.     

中国矿工就业观念新变化--对阜新破产前的海州煤矿和劳动力市场的调查

资源枯竭型城市是我国就业形势最为严重的地区。阜新市是国务院确定的资源枯竭型城市经济转型唯一试点，本文在对阜新市海州煤矿职工和劳动力市场就业观念问卷调查的基础上，分析得出我国矿业职工的就业观念虽然还存在一些问题，但发生了许多可喜的变化。这些变化的重要意义在于，各级政府在制定再就业政策时要适应这些新变化，扩展和开辟相应的再就业渠道。     

基于CAD的矿图参数识别分析

提出了基于CAD环境下的矿图标准化处理规则,给出了采区、断层等图形元素的获取方法,为矿井图形信息管理提供了有效途径。