关键词： 微重力   毛细流动   磁补偿   水基磁流体   接触角   内角  

摘要： 由于表面张力的作用,流体在微重力环境中沿一定夹角的内角壁面爬升过程与常重力状态不同。为了对微重力内角流动的物理过程进行研究,利用磁补偿方法搭建了常温磁流体微重力补偿实验台,实现了目标区域内纵向小于5%非均匀度的磁补偿微重力环境。并对不同重力条件下水基磁流体沿若干材料内角爬升过程进行了可视化实验研究,探究了微重力环境下流体与材料间的接触角以及内角角度对液体导流性能的影响以及毛细流动规律。结果表明,在满足Concus-Finn条件时,液面爬升高度和重力加速度近似呈反比关系。接触角和内角角度越小,流体输运能力越强,且重力水平越低,越为明显。当不满足Concus-Finn条件时,液面爬升高度和重力加速度近似呈线性关系,接触角和内角角度对流体输运能力的影响并不明显。

关键词： 地热流体   稳定同位素   放射性同位素   柏乡县  

摘要： 本次采用11组稳定同位素地下水样品数据,对其地热流体来源、迁移特征进行了研究,确定了补给来源、补给高程及其水力联系等;采用放射性同位素数据,研究了地热流体年龄。结果表明:本区地热流体主要源于大气降水;地热流体滞留时间较长,具有深部水循环特征;地下水中HCO-3和CO2-3主要来源于土壤或有机质分解,并且有地表冷水混入到向上运移的地下水中,大气溶解的CO2进入水中导致HCO-3的含量增加;研究区地下水中的硫主要来源于沉积层的溶滤作用。研究成果为本区地热水的勘查、开发奠定了基础。

关键词： Thermo-hydromechanical coupling   Displacement discontinuity method   Thermoelasticity   Poroelasticity  

摘要： Geothermal reservoirs, oil wells, radioactive waste disposals, and deep underground mines deal with high-temperature and high-pressure problems. The thermo-hydromechanical coupling may significantly affect the behavior of the rock mass in these applications. Fractures and joints are the main conduits of thermal and hydraulic transition. The displacement discontinuity method (DDM) is ideally suited to model problems containing fractures. However, the DDM in its original formulation is restricted to elasticity problems. It is formulated in this study to take into account the thermo-hydromechanical effects. A numerical formulation and implementation for the thermo-hydromechanical DDM is derived. The proposed numerical model is validated in three parts. The poroelastic, thermoelastic, and thermo-hydromechanical couplings are each validated by analytical or experimental results. The results showed good agreement between the proposed numerical model and analytical or experimental results over various periods. The validations proved the accuracy and applicability of the proposed thermo-hydromechanical numerical model in a wide range of problems. Furthermore, the thermo-hydromechanical effect on crack opening displacement (COD) is modeled. Numerical simulation showed that the maximum COD due to only thermal effects may be reached after almost a year. (C) 2020 Elsevier Ltd. All rights reserved.

关键词： Solidified silt   underwater casting   pH   turbidity   heavy metals  

摘要： With the growing demand for underwater refill engineering, the construction technology of implementing fluidized solidification in underwater pouring has recently received increased attention. However, the environmental impact of underwater casting on surrounding water bodies, especially when the silt is polluted, is still unclear. In this study, a simulated underwater pouring test and a static immersion release test were conducted separately to study the quality of the surrounding water during and after pouring. The results showed that fluidized-solidified silt casting could increase the pH of the surrounding water, even after the pouring had stopped, by approximately 1.0 and the turbidity could reach 200 NTU. No diffusion of Zn and Cu into the surrounding water was observed and while Ni and Cr exhibited slight diffusion, this was at a level well below international water quality standard. During construction, reducing the distance from the seafloor to the bottom of the pouring catheter could reduce the level of pollution. After construction, the use of neutral solidified materials can effectively reduce the pH of the surrounding water and the potential risk of heavy metal dissolution.

关键词： Circulating fluidized beds   Liquid-solid fluidization   Gas-liquid-solid fluidization   Potential applications   Proteins recovery   Wastewater treatment  

摘要： Circulating fluidized beds (CFBs) possess many significant advantages over conventional fluidized beds, including enhanced interfacial contact efficiency and reduced back-mixing. Building on the many successful industrial applications of gas-solid CFBs, liquid-solid circulating fluidized beds (LSCFBs) and gas-liquid-solid circulating fluidized beds (GLSCFBs) have recently also received increasing interests due to their massive potential in chemical-biochemical, environmental and pharmaceutical processes. This review summarizes the progress in the past several decades concerning LSCFBs and GLSCFBs, with more emphasis placed on the reported applications, after a general description of the unique features of the two types of CFBs. Most of the examples given in this review are still in laboratory-scale, but useful guidance can be provided to researchers or companies for further study and/or commercial exploration.

关键词： Bubbles   Atmospheric chemistry   Interfaces   Biomass   Theoretical models  

摘要： Biomass gasification in fluidized beds is a process of important commercial value. The simulation of these fluidized bed units strongly depends on establishing bubble dynamics in dense phase sand fluidized beds. In these studies, the selected biomass pellet dimensions were 2.7 cm in length and 0.8 cm in diameter. To develop bubble dynamics studies in the present research, a combination of CREC-Optiprobes and a video micro-camera were employed. This was done to record bubble velocity and bubble dimensions in a 200-900 mu m particle sand fluidized bed. The effects of biomass pellet concentration on the bubble rise velocity and bubble size and shape were evaluated at conditions close to minimum fluidization. On this basis, a theoretical bubble dynamic model was established. This phenomenologically based model included an adjustable bubble wake parameter, with model predictions providing the bubble chord, bubble frontal ratio, and bubble rising velocity.

关键词： Bituminous coal   lignite   SO2 emission   O-2   N-2   O-2   CO2   fluidized bed  

摘要： A complex analysis of the influence of various atmospheres on SO2 emission is presented by comparing two types of coal under the following conditions: combusted alone and mixed with biomass. The results are correlated with the content of pyrite, sulfate and organic sulfur in both coal types. SO2 emission in different atmospheres was compared separately for each coal type, reporting it in percentage of emission in the air for the same mass of coal sample. We found a strong dependence of SO2 emission on the combustion atmosphere in case of bituminous coal, whereas we found a weak dependence in case of lignite. Combustion of bituminous coal in oxygen enhanced atmosphere resulted in a high increase in SO2 emission. A significant reduction in the emission of SO2 was obtained by combusting either bituminous coal alone in O-2/CO2 atmosphere or in a blend with biomass in O-2/N-2 or O-2/CO2 atmospheres.

关键词： 食用菌   电子商务   冷链物流   冷链仓储  

摘要： 为进一步推动食用菌冷链物流行业的发展,建立电商环境下的现代化物流体系。在讨论食用菌冷链物流体系设计原则的基础上,从第三方仓储公司的选择和冷链仓储管理的角度,对食用菌冷链物流体系的仓储子系统进行了设计。该设计方案可以有效提升食用菌冷链物流的仓储效率,促进了电商环境下食用菌冷链物流行业的良性发展。

关键词： 白细胞与血小板相互作用   细胞黏附   壁面剪切应力   血管性血友病因子  

摘要： 目的在流体剪切应力条件下,探究力学微环境对嗜中性粒细胞在活化血小板上滚动黏附的影响。方法实验在平行平板流动腔中进行。流动腔底板通过吸附v WF-A1而功能化,黏附于功能化底板的血小板通过灌注PBS施加1 Pa壁面剪切应力(wall shear stress,WSS)刺激,力学刺激时间分别为0、2.5和7.5 min。利用高速摄像机观察和记录WSS=50 m Pa条件下白细胞在活化血小板上的滚动黏附行为,提取黏附事件数、细胞拴缚停留时间及滚动速度等参数。结果中性粒细胞能特异性的结合到v WF-A1介导的稳定黏附于流动腔底部的血小板上;白细胞在血小板上的拴缚停留时间不依赖于力学刺激,但力学刺激会显著促进白细胞在血小板上的黏附,降低白细胞在血小板上的滚动速度。结论力学刺激血小板将显著提高血小板捕获循环白细胞的能力,促进白细胞在血小板上的滚动黏附。