作者： 唐振平;肖莎莎;段毅;刘迎九;高媛媛;...

期刊： 环境科学,2021年42(7):3375-3384 ISSN：0250-3301

通讯作者： Zhou, Shuai(zs402606665@126.com)

作者机构： [唐振平; 段毅; 刘迎九; 周帅] Hunan Province Key Laboratory of Pollution Control and Resources Reuse Technology, University of South China, Hengyang;421001, China;Hunan Key Laboratory of Rare Metal Minerals Exploitation and Geological Disposal of Wastes, Hengyang;[肖莎莎; 高媛媛] School of Civil Engineering, University of South China, Hengyang;[吴月月; 陈怡雯] Institute of Pathogenic Biology, Hengyang Medical College, University of South China, Hengyang

关键词： 石化废水;耐药菌(ARB);耐药基因(ARGs);分布;去除;影响因子

摘要： 抗生素耐药性污染已成为全球新兴环境问题之一.本研究选取某座石化废水处理厂,对耐药菌(ARB)和3种形态耐药基因(ARGs):细胞内耐药基因(iARGs) 、细胞外附着态耐药基因(aeARGs)和游离态耐药基因(feARGs)的分布特征与去除效能开展研究.结果表明,废水处理厂中检出四环素、磺胺和氨苄西林这3类ARB,其绝对浓度为8.45×10~2 ~ 2.38×10~5CFU·mL~(-1).厌氧处理可使这3类ARB绝对浓度下降0.04 lg ~ 0.21 lg;曝气和沉淀处理对ARB的影响因其类型而异;出水ARB绝对浓度高出进水水平0.12 lg ~ 0.63 lg.活性污泥中aeARGs和iARGs绝对丰度分别为1.96×10~7 ~ 3.02×10~(10) copies·g~(-1)和5.22×10~7 ~ 4.15×10~(10) copies·g~(-1);而废水中feARGs绝对丰度为5.90×10~8 ~ 1.01×10~(12) copies·L~(-1).厌氧处理可去除0.13 lg ~ 0.65 lg aeARGs和0.04 lg ~ 0.28 lg iARGs;曝气和沉淀处理对aeARGs和iARGs的去除效果受ARGs类型和形态影响;出水中feARGs绝对丰度较进水升高0.06 lg ~ 0.81 lg.冗余分析表明,ARB浓度与COD、Cl~-和总氮浓度显著正相关(P < 0.05); aeARGs丰度与COD和总氮浓度显著正相关(P < 0.05); iARGs和feARGs丰度均与重金属浓度显著正相关(P < 0.05).本研究证实了石化废水处理厂具有ARB和不同形态ARGs的富集风险,并为特种工业废水耐药性污染研究与防治提供理论基础.

语种： 中文

作者： Ke, Guojun;Xu, Xin;Fang, Yaochu;Song, Baixing;Jin, Dan;...

期刊： FULLERENES NANOTUBES AND CARBON NANOSTRUCTURES,2021年29(12):1016-1025 ISSN：1536-383X

通讯作者： Zuo, Junqing

作者机构： [Fang, Yaochu; Song, Baixing; Ke, Guojun; Xu, Xin; Jin, Dan] Univ South China, Sch Civil Engn, Hengyang, Peoples R China.;[Zuo, Junqing] Shanghai Construct Grp Co Ltd, Shanghai 200080, Peoples R China.

通讯机构： [Junqing Zuo] S;Shanghai Construction Group Co., Ltd, Shanghai, China.

关键词： Layered double hydroxides;carbon nanotubes;concrete;mechanical properties;constitutive equation

摘要： Co-Fe-Mg-Al quaternary hydrotalcite-carbon nanotube composites (LDH-CNT composites) were prepared by co-precipitation method and blended into concrete. Universal testing machine and SHPB testing device were used to carry out static and dynamic tests on LDH-CNT concrete specimens with different LDH-CNT additions (0, 0.25 wt.%, 0.5 wt.%), and the dynamic constitutive equation was obtained according to the dynamic stress-strain curve. Results show that compared with ordinary concrete, the compressive strength and toughness of LDH-CNT concrete have been greatly improved. When the LDH-CNT composites content is 0.5 wt.%, the strength and toughness are increased by 10.8% and 16.3%, respectively; The dynamic compression mechanical properties of LDH-CNT concrete show a significant strain rate effect, and the impact compression mechanical parameters increase with the increase of the maximum strain rate. In the strain rate range of 10°∼102s−1, the theoretical curve and the measured curve fit better, and the constitutive equation can describe the dynamic mechanical response of LDH-CNT concrete. © 2021 Taylor & Francis Group, LLC.

语种： 英文

作者： 杨聪聪;任承钦;杨洋;涂敏

期刊： 中南大学学报(自然科学版),2021年52(6):1747-1756 ISSN：1672-7207

通讯作者： Ren, Chengqin(renchengqin@163.com)

作者机构： [杨聪聪; 任承钦; 杨洋] College of Mechanical and Vehicle Engineering, Hunan University, Changsha;410082, China;[涂敏] School of Civil Engineering, University of South China, Hengyang;421001, China;[杨聪聪; 任承钦; 杨洋] 410082, China

关键词： 蒸发冷却;新风空调器;能量分析;㶲分析

摘要： 基于能量和㶲分析的方法对2种传统型和2种改进型蒸发冷却新风空调器(FAC)进行对比;将各FAC和机械蒸汽压缩空调(MVC)组成4种不同的蒸发冷却复合空调(HAC),对其节能性进行对比分析。首先,建立喷淋填料和翅片式表冷器的分布式参数模型以及MVC的关联式模型,并对喷淋填料和翅片式表冷器的数学模型进行验证。其次,研究4个独立参数(环境空气温度、含湿量、新风质量流量和传热单元数)对各FAC的性能系数(COP)、㶲效率和㶲效比的影响以及对各HAC节能率的影响。最后,评估4种HAC在气候干热的吐鲁番的夏季季节性节能潜力。研究结果表明:各FAC的㶲效率和㶲效比随环境空气温度增加而升高,随新风质量流量的增加而降低,随传热单元数的增加先升高后降低(FAC-C除外);所有HAC均适用于干热气候地区,其节能率随新风质量流量和传热单元数的增加先升高后降低;在吐鲁番,HAC比通入新风的MVC节能24.7%~32.8%;HAC-D的节能率始终最大,它是4种方案中的首推方案。

语种： 中文

作者： 葛玉杰;吴姣;王国华;周帅;刘金香

期刊： 原子能科学技术,2021年55(4):603-611 ISSN：1000-6931

通讯作者： Liu, Jinxiang(cafardworm@163.com)

作者机构： [葛玉杰; 吴姣; 王国华; 周帅; 刘金香] School of Civil Engineering, University of South China, Hengyang;421001, China;Hunan Provincial Key Laboratory of Pollution Control and Resources Technology, University of South China, Hengyang;[葛玉杰; 吴姣; 王国华; 周帅; 刘金香] 421001, China;[王国华; 周帅; 刘金香] 421001, China <&wdkj&> Hunan Provincial Key Laboratory of Pollution Control and Resources Technology, University of South China, Hengyang

关键词： 石墨相氮化碳;多孔石墨相氮化碳;吸附机理

摘要： 以三聚氰胺为原料、碳酸钙为辅助模板,采用热聚合法对石墨相氮化碳(g-C3 N4)进行改性,制备了多孔石墨相氮化碳(PCN)材料,研究了g-C3 N4改性前后对U(Ⅵ)的吸附效果,并利用SEM、BET、FT-IR、XPS等表征手段对PCN吸附U(Ⅵ)的机理进行了分析.结果表明:PCN比表面积显著增大(58.5 m2/g),约为g-C3 N4的4倍;在初始pH=5、吸附时间2 h、U(Ⅵ)初始浓度10 mg/L、PCN用量0.2 g/L、温度303 K条件下,PCN对U(Ⅵ)的最大吸附量为92 mg/g;整个吸附过程符合准二级动力学方程以及Langmuir等温吸附模型;此外,升高温度有利于PCN对U(Ⅵ)的吸附.FT-IR、XPS表征结果表明,PCN中的含氮基团参与了PCN对U(Ⅵ)的吸附去除.

语种： 中文

作者： Yang, Yang;Ren, Chengqin*;Yang, Congcong;Tu, Min;Luo, Baojun;...

期刊： Energy Conversion and Management,2021年230:113824 ISSN：0196-8904

通讯作者： Ren, Chengqin

作者机构： [Fu, Jianqin; Ren, Chengqin; Yang, Congcong; Luo, Baojun; Yang, Yang] Hunan Univ, Coll Mech & Vehicle Engn, State Key Lab Adv Design & Mfg Vehicle Body, Changsha 410082, Peoples R China.;[Tu, Min] Univ South China, Sch Civil Engn, Hengyang 421001, Peoples R China.

通讯机构： [Ren, Chengqin] H;Hunan Univ, Coll Mech & Vehicle Engn, State Key Lab Adv Design & Mfg Vehicle Body, Changsha 410082, Peoples R China.

关键词： Energy analysis;Energy recovery;Evaporative cooling;Exergy analysis;Seasonal energy saving potential evaluation

摘要： External-cooling indirect evaporative cooling is an effective energy saving technology, where air–water finned coils are linked with packed cooling tower by water pipes. However, external-cooling indirect evaporative coolers with different configurations and working air sources are incomprehensively analyzed and compared. This study presented an energy and exergy analysis of five external-cooling indirect evaporative coolers, including conventional configuration, dew point configuration, newly patented dew point configuration, and energy recovery forms of the first two. In order to analyze the evaporative cooler and its hybrid system combined with mechanical vapor compression system, the numerical model and experimental correlation are used. The effect of four selected parameters (ambient temperature, ambient humidity ratio, total number of transfer units and fresh air flowrate), and the summer energy saving potential in three different cities are studied. The analysis results show that the new dew point configuration has the best performance under the conditions of high temperature, high humidity, and high fresh air flowrate. This new dew point cooler's hybrid system achieves the best energy saving rate in humid and arid climates, between 19.1% and 48.5% compared with the pure mechanical vapor compression system. In this study, the advantages and disadvantages of presented designs are established and their application potential under different climates is estimated. © 2021 Elsevier Ltd

语种： 英文

作者： 朱奥琦;谢水波;司子彦;刘迎久;莫官海

期刊： 原子能科学技术,2020年54(10):1753-1761 ISSN：1000-6931

通讯作者： Xie, Shuibo(xiesbmr@263.net)

作者机构： [朱奥琦; 司子彦; 莫官海] School of Civil Engineering, University of South China, Hengyang;421001, China;[谢水波; 刘迎久] Hunan Provincial Key Laboratory of Pollution Control and Resources Technology, University of South China, Hengyang;[朱奥琦; 谢水波; 司子彦; 刘迎久; 莫官海] 421001, China

通讯机构： Hunan Provincial Key Laboratory of Pollution Control and Resources Technology, University of South China, Hengyang, China

关键词： 介孔二氧化硅;β-环糊精;吸附

摘要： 以三乙氧基(3-异氰酸丙基)硅为交联剂,通过后接枝法合成了β-环糊精改性介孔二氧化硅(SBA-15-CD)材料.通过静态吸附试验研究了溶液pH值、SBA-15-CD投加量、吸附时间、温度等因素对SBA-15-CD吸附U(Ⅵ)的影响.通过扫描电镜(SEM)、X射线粉末衍射(XRD)、BET比表面分析、傅里叶红外光谱(FT-IR)和X射线光电子能谱(XPS)对材料进行表征分析,并探讨了SBA-15-CD吸附U(Ⅵ)的机制.结果表明,当U(Ⅵ)初始浓度为5 mg/L、温度为30℃时,SBA-15-CD吸附U(Ⅵ)的最佳条件为:pH=5、SBA-15-CD投加量0.20 g/L、吸附平衡时间30 min,在此条件下,平衡吸附量为24.4 mg/g,U(Ⅵ)去除率为98.3％.吸附过程符合准二级动力学模型和Langmuir等温模型,即以化学吸附为主,且主要是通过表面的羟基、酯基和氨基与U(Ⅵ)配位.30℃下SBA-15-CD的饱和吸附量达330 mg/g,升高温度有利于吸附的进行.SBA-15-CD具有良好的重复使用性能.

语种： 中文

作者： Wang, Rui;Wang, Jingsong*

期刊： Annals of Nuclear Energy,2020年147:107679 ISSN：0306-4549

通讯作者： Wang, Jingsong

作者机构： [Wang, Rui] Univ South China, Sch Resource Environm & Safety Engn, Hengyang 421001, Hunan, Peoples R China.;[Wang, Jingsong] Univ South China, Sch Civil Engn, Hengyang 421001, Hunan, Peoples R China.

通讯机构： [Wang, Jingsong] U;Univ South China, Sch Civil Engn, Hengyang 421001, Hunan, Peoples R China.

关键词： Cement solidification;HAZOP;Out-drum mixing;Risk analysis;Risk matrix

摘要： Due to the particularity and complexity of cement solidification, radioactive waste may be released and diffused, causing serious radioactive hazards to equipment, operators and environment. In this study, hazard and operability analysis (HAZOP) and risk matrix were combined to identify and evaluate risks of out-drum mixing cement solidification. Firstly, based on concept and steps of HAZOP, the meaningful deviations of out-drum mixing equipment were described by appropriate guidewords and process parameters. Secondly, the causes and consequences of deviation, and the safety measures were investigated. Finally risk matrix was applied to classify risk level and assess risk of the identified deviation. Results indicated that low level of wet waste in storage and weighing tank, less flow of wet waste in feeding pipe of storage and weighing tank, mixer without mixing speed, high transport speed and additional location of drum are unacceptable risks. The relevant safety suggestions were given to reduce or eliminate potential hazards. © 2020 Elsevier Ltd

语种： 英文

作者： Zeng, Taotao*;Mo, Guanhai;Hu, Qing;Wang, Guohua;Liao, Wei;...

期刊： Environmental Pollution,2020年261(Jun.):114176 ISSN：0269-7491

通讯作者： Zeng, Taotao

作者机构： [Liao, Wei; Xie, Shuibo; Mo, Guanhai; Zeng, Taotao; Wang, Guohua; Hu, Qing] Univ South China, Hunan Prov Key Lab Pollut Control & Resources Reu, Hengyang 421001, Peoples R China.;[Xie, Shuibo] Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Peoples R China.

通讯机构： [Zeng, Taotao] U;Univ South China, Hunan Prov Key Lab Pollut Control & Resources Reu, Hengyang 421001, Peoples R China.

关键词： Uranium;Bacterial community;High-throughput sequencing;Microbial characteristic

摘要： The microbial characteristics and bacterial communities of sediment sludge upon different concentrations of exposure to uranium were investigated by high solution transmission electron microscopy (HRTEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS) and high-throughput sequencing. After exposure to initial uranium concentrations of 10-50 mu M for 24 h in synthetic wastewater, the removal efficiencies of uranium reached 80.7%-96.5%. The spherical and short rod bacteria were dominant in the sludge exposed to uranium. HRTEM-EDS and XPS analyses indicated that reduction and adsorption were the main mechanisms for uranium removal. Short-term exposure to low concentrations of uranium resulted in a decrease in bacterial richness but an increase in diversity. A dramatic change in the composition and abundances of the bacterial community were present in the sediment sludge exposed to uranium. The highest removal efficiency was identified in the sediment sludge exposed to 30 mu M uranium, and the dominant bacteria included Acinetobacter (44.9%), Klebsiella (20.0%), Proteiniclasticum (6.7%), Enterobacteriaceae (6.6%), Desulfovibrio (4.4%), Porphyromonadaceae (4.1%), Comamonas (2.4%) and Sedimentibacter (2.3%). By comparison to the inoculum sediment sludge, exposure to uranium caused a substantial difference in the majority of bacterial abundance. (C) 2020 Elsevier Ltd. All rights reserved.

语种： 英文

作者： 刘清;邓真宁;滑熠龙;招国栋

期刊： 化工进展,2020年39(5):1950-1963 ISSN：1000-6613

通讯作者： Liu, Qing(liuqing197901@163.com)

作者机构： [刘清; 邓真宁] Hunan Province Key Laboratory of Pollution Control and Resources Reuse Technology, University of South China, Hengyang;Hunan;421001, China;[滑熠龙] Key Discipline Laboratory for National Defence for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang;[招国栋] School of Resource & Environment and Safety Engineering, University of South China, Hengyang

关键词： 纳米粒子;纳米零价铁;铁氧化物;绿色合成;环境;污染

摘要： 纳米铁(零价铁及铁氧化物)比表面积大、还原能力强、反应活性高,是一种良好的环境功能材料。传统的纳米铁合成方法中,物理方法对反应所需仪器设备要求较高,化学方法使用的还原剂具有毒性,绿色合成方法能够有效克服传统方法的不足之处。本文首先根据合成途径、纳米铁的类型介绍了利用植物和微生物对纳米零价铁(nZVI)及纳米铁氧化物(IONPs)进行绿色合成的方法,同时论述了制备的纳米铁所表现的特征(如形貌、尺寸、聚集倾向、等电位点)。随后总结了纳米铁通过不同反应机制(吸附、还原、催化氧化)去除环境有机、无机污染物(染料、芳香族化合物、硝酸盐、重金属)的应用。最后指出了纳米铁在绿色合成与实际应用过程中存在的挑战性问题及解决方法,以期为纳米铁今后的深入研究和大规模的工业生产应用提供参考依据。

语种： 中文

作者： Wang, Lei;Liu, Run-Zhe;Liu, Di;Zhao, Fu-Yun*;Wang, Han-Qing

期刊： International Journal of Thermal Sciences,2020年147:106138 ISSN：1290-0729

通讯作者： Zhao, Fu-Yun

作者机构： [Liu, Run-Zhe; Zhao, Fu-Yun; Wang, Lei] Wuhan Univ, Minist Educ, Key Lab Hydraul Machinery Transients, Wuhan, Hubei, Peoples R China.;[Liu, Run-Zhe; Zhao, Fu-Yun; Wang, Lei] Wuhan Univ, Hubei Key Lab Waterjet Theory & New Technol, Wuhan, Hubei, Peoples R China.;[Liu, Run-Zhe; Zhao, Fu-Yun; Wang, Lei] Wuhan Univ, Sch Power & Mech Engn, Dong Hu South Rd, Wuhan 430072, Hubei, Peoples R China.;[Liu, Di] China Univ Petr, Coll Pipeline & Civil Engn, Qingdao, Shandong, Peoples R China.;[Wang, Han-Qing] Univ South China, Sch Civil Engn, Hengyang, Hunan, Peoples R China.

通讯机构： [Zhao, Fu-Yun] W;Wuhan Univ, Sch Power & Mech Engn, Dong Hu South Rd, Wuhan 430072, Hubei, Peoples R China.

关键词： Buoyancy;Deterioration;Electronic cooling;Enclosures;Flow of fluids;Heat conduction;Heat resistance;Heat transfer performance;Morphology;Natural convection;Navier Stokes equations;Porous materials;Thermal conductivity;Forchheimer models;Governing parameters;Heat Transfer enhancement;Heated enclosures;Laminar natural convection;Natural convection flow;Numerical heat transfer;Porous fins;Fins (heat exchange)

摘要： The application of porous media for electronic cooling process, instead of solid one, generally strengthens heat conduction while weakens convection insignificantly at high Darcy number. In the present work, effects of morphology and topology of porous fins on the laminar natural convection heat transfer were investigated in a differentially heated enclosure. Volume averaged Darcy-Forchheimer model was applied to solve the transport process within the porous media while the Navier-Stokes equations were employed within pure fluid region. Relevant governing parameters, including thermal Rayleigh number, Darcy number, thermal conductivity of the porous matrix, designs of porous fins, are sensitively varied to identify their effects and roles on the natural convection flows. Depending on thousands of numerical data, the correlation has been developed for all designs of porous fins. Numerical results illustrate that the adding porous fins with excellent permeability and heat conduction contribute to the remarkable heat transfer enhancement while the adding fins, acting like solid ones and having poor heat conduction, could result in an increase of thermal resistance and the deterioration of heat transfer. Numerical results further show that there exists an optimal design of porous fins to achieve the best performance of heat transfer if some conditions were satisfied. Overall, this study could benefit the electronic cooling by the installation of porous-alike materials. © 2019 Elsevier Masson SAS

语种： 英文

作者： Zhao, Jinping;Wang, Hanqing;Li, Yuguo;Xiao, Fang;Deng, Qihong*

期刊： Building and Environment,2020年173:106752 ISSN：0360-1323

通讯作者： Deng, Qihong

作者机构： [Zhao, Jinping; Deng, Qihong] Cent South Univ, Sch Energy Sci & Engn, Changsha, Hunan, Peoples R China.;[Zhao, Jinping; Wang, Hanqing] Univ South China, Sch Civil Engn, Hengyang, Hunan, Peoples R China.;[Wang, Hanqing] Univ South China, Prov Engn Lab Hunan Technol Bldg Environm Control, Hengyang, Hunan, Peoples R China.;[Li, Yuguo] Univ Hong Kong, Dept Mech Engn, Hong Kong, Peoples R China.;[Xiao, Fang; Deng, Qihong] Cent South Univ, XiangYa Sch Publ Hlth, Changsha, Hunan, Peoples R China.

通讯机构： [Deng, Qihong] C;Cent South Univ, Sch Energy Sci & Engn, Changsha, Hunan, Peoples R China.

关键词： Cooling treatment;Core temperature;Heat wave;Hypothermia;Indoor environment;Thermoregulatory model

摘要： Background: As global warming continues, incidences of heatstroke will become more prevalent. Since most deaths occur at home, timely and effective in-home treatment is critical to reduce heatstroke mortality. However, in-home treatment is limited by lack of knowledge and guidance. Objectives: To predict the course of heatstroke recovery over time for different home environment conditions, so as to provide useful information and technical guidance for heatstroke treatment. Methods: We suggested a new multi-node human thermoregulatory model by considering the effect of thermoregulatory impairment, delayed shivering and vasoconstriction, due to heatstroke on the course of recovery. The role of home environmental conditions in the course of heatstroke recovery was examined, to identify optimal treatment conditions. Results: Our thermoregulation modeling shows that the course of body core temperature during heatstroke recovery consists of three distinct stages: a rapid cooling stage due to vasodilation, a slower cooling stage due to vasoconstriction and a rewarming stage due to shivering. Our modeling results showed that hypothermia is a necessary condition for successful recovery, which cannot be achieved by the classical thermoregulatory model. We found that lower indoor temperature or higher ventilation can accelerate the cooling stage and that a higher indoor temperature or lower ventilation would be helpful in the rewarming stage, which indicated an optimal indoor condition for improving the recovery of heatstroke. To improve the chances of a full recovery, it is also necessary to carry out cooling treatment for a heatstroke patient as early as possible. Our new model was validated by rat experiments and the available human data. Conclusions: Onsite treatment of heatstroke should begin as early as possible. Our new thermoregulatory model can predict the course of body temperature changes overtime during heatstroke recovery, and hence may be used to develop effective in-home treatments. © 2020 Elsevier Ltd

语种： 英文

作者： 焦楚杰;李松;甘元初

期刊： 东南大学学报(自然科学版),2020年50(2):222-230 ISSN：1001-0505

作者机构： [焦楚杰; 李松] School of Civil Engineering, Guangzhou University, Guangzhou;510006, China;[甘元初] School of Civil Engineering, University of South China, Hengyang;421001, China;[焦楚杰; 李松] 510006, China

关键词： 废玻璃粉混凝土;单轴受压;应力-应变全曲线;峰值应力;延性系数

摘要： 为研究废玻璃粉混凝土单轴受压作用下的全过程受力特征,对C30与C50两类强度等级,0%、10%、15%、20%、25%、30%六种取代率下的棱柱体试件进行单轴受压应力-应变全曲线试验.通过试验分析了应力-应变全过程曲线变化趋势,对比研究了比例极限、峰值应力、延性系数等性能指标,并采用分段式本构关系对废玻璃粉混凝土应力-应变全曲线进行了研究.结果表明:废玻璃粉混凝土应力-应变全曲线形状与普通混凝土相似,随着取代率的增加,上升段斜率逐渐变小,下降段则趋于平缓,各类取代率下均值曲线的标准差先增大后减小,直至保持不变;与普通混凝土相比,废玻璃粉混凝土的比例极限相对较小,峰值应变则较大,延性较好的原因在于上升段表现出的塑性变形较强;分段式本构方程计算所得曲线与试验所测曲线吻合良好,C30强度等级下上升段参数为2.146,下降段参数为0.8,C50强度等级下上升段参数为1.987,下降段参数为1.462.

语种： 中文

作者： Feng, Shengyang;Xiong, Dongbo;Chen, Guojie;Cui, Yu;Chen, Puxin

期刊： 流体力学与材料加工(英文),2020年16(3):651-663 ISSN：1555-256X

通讯作者： Feng, Shengyang(14100044@usc.edu.cn)

作者机构： [Feng, Shengyang; Cui, Yu; Chen, Puxin] School of Resource Environment and Safety Engineering, University of South China, Hengyang;421001, China;Hunan Province Engineering Technology Research Center of Uranium Tailings Treatment, Hengyang;Hunan Province Engineering Research Center of Radioactive Control Technology in Uranium Mining and Metallurgy, Hengyang;[Xiong, Dongbo] Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai

通讯机构： [Feng, S.] S;School of Resource Environment and Safety Engineering, China

关键词： Convective diffusion;numerical simulation;radon migration;turbulence

摘要： Convection and diffusion are the main factors affecting radon migration. In this paper, a coupled diffusion-convection radon migration model is presented taking into account turbulence effects. In particular, the migration of radon is simulated in the framework of the k-å turbulence model. The model equations are solved in a complex 3D domain by the finite element method (FEM). Special attention is paid to the case study about radon migration in an abandoned air defense shelter (AADS). The results show that air convection in a confined space has a great influence on the radon migration and the radon concentration is inversely proportional to the wind speed. © 2020

语种： 英文

作者： Yang, Yang;Ren, Chengqin*;Tu, Min;Luo, Baojun;Fu, Jianqin

期刊： International Journal of Refrigeration,2020年117:1-11 ISSN：0140-7007

通讯作者： Ren, Chengqin

作者机构： [Fu, Jianqin; Ren, Chengqin; Luo, Baojun; Yang, Yang] Hunan Univ, Coll Mech & Vehicle Engn, State Key Lab Adv Design & Mfg Vehicle Body, Changsha 410082, Hunan, Peoples R China.;[Tu, Min] Univ South China, Sch Civil Engn, Hengyang 421001, Peoples R China.

通讯机构： [Ren, Chengqin] H;Hunan Univ, Coll Mech & Vehicle Engn, State Key Lab Adv Design & Mfg Vehicle Body, Changsha 410082, Hunan, Peoples R China.

关键词： Air;Air conditioning;Domestic appliances;Energy utilization;Heat exchangers;Packed beds;Recovery;Rivers;Specific heat;Building energy consumption;Conventional systems;Energy saving potential;Lower yangtze rivers;Mechanical vapor compressions;Parametric -analysis;Theoretical performance;Total energy recoveries;Energy efficiency

摘要： Energy recovery technologies can effectively improve the energy efficiency of air-conditioning systems and significantly reduce building energy consumption. In this paper, a parametric analysis and energy-saving potential evaluation for a new hybrid air conditioning system (HAC) is carried out theoretically based on developed models. The proposed HAC incorporates into a conventional mechanical vapor compression air conditioning system with an independent fresh air conditioner which is composed of a network of heat exchangers, including a packed bed and three air-water finned coils. Under cold winter climate, in the fresh air conditioner, a packed bed is coupled with a water-air heat exchange coil to form a total energy recovery loop. A run-around sensible energy recovery loop is also integrated in the system to produce a two-stage energy recovery effect. Moreover, a sprayer is installed upstream of the two-stage energy recovery process for fresh air humidification, and a fresh air recirculation duct is equipped for frost-free operation. In the parametric analysis, four independent affecting parameters are included: the air-to-water heat capacity ratio, the indoor temperature, the ambient temperature, and the ratio of recirculation fresh air. The energy-saving potential of the HAC is also evaluated for applications in seven typical cities located in middle-lower Yangtze River region of China over the winter period (December, January and February). The results show that compared with the conventional system with electric humidification, the HAC has an average energy saving rate of 44.0%, and its average power saving per hour is 13.41 W m−2. © 2020

语种： 英文

作者： Wang, Rui;Wang, Jingsong*;Dong, Teng;Ouyang, Gaoshang

期刊： Construction and Building Materials,2020年240:117935 ISSN：0950-0618

通讯作者： Wang, Jingsong

作者机构： [Wang, Rui] Univ South China, Sch Resource Environm & Safety Engn, Hengyang 421001, Hunan, Peoples R China.;[Ouyang, Gaoshang; Wang, Jingsong; Dong, Teng] Univ South China, Sch Civil Engn, Hengyang 421001, Hunan, Peoples R China.;[Wang, Jingsong] Univ South China, Yangtze Delta Res Inst, Zhuji 311800, Zhejiang, Peoples R China.

通讯机构： [Wang, Jingsong] U;Univ South China, Sch Civil Engn, Hengyang 421001, Hunan, Peoples R China.

关键词： Aluminosilicate powder;Geopolymer;Mechanical properties;Molecular dynamics simulation;SiO2/Al2O3 ratio;Structural properties

摘要： In this study, the impacts of different SiO2/Al2O3 ratio on the molecular structural and mechanical properties of geopolymer were investigated by molecular dynamics and experiment. Complex composition of raw materials may affect the analysis of geopolymer gels. Therefore, pure aluminosilicate powder with different SiO2/Al2O3 ratio were synthesized by sol-gel method firstly. Then the prepared powder mixed with the activating agent of NaOH and sodium silicate to prepare geopolymer. After 28d curing age, chemical composition and crystalline phase of geopolymer were characterized by X-ray fluorescence(XRF) and X-ray Diffraction (XRD) respectively. Based on the above characterization results of geopolymer gel, different SiO2/Al2O3 ratio of molecular models were built. Finally, molecular dynamics were performed on the molecular models to study energy and temperature, simulated XRD, radial distribution function (RDF), distribution of bond length and bond angle and elastic modulus. Results showed that with the increases of SiO2/Al2O3 ratio, both stability of molecular structure and mechanical properties of geopolymer were decreased. © 2019 Elsevier Ltd

语种： 英文

作者： Feng, Shengyang*;Wang, Hanqing;Cui, Yu;Ye, Yongjun;Liu, Yong*;...

期刊： Computers and Geotechnics,2020年128:103810 ISSN：0266-352X

通讯作者： Feng, Shengyang;Liu, Yong

作者机构： [Cui, Yu; Ye, Yongjun; Yang, Rong; Feng, Shengyang; Wang, Hong; Liu, Yong; Feng, SY; Li, Xiangyang] Univ South China, Sch Resource Environm & Safety Engn, Hengyang 421001, Hunan, Peoples R China.;[Wang, Hanqing] Univ South China, Sch Civil Engn, Hengyang 421001, Peoples R China.;[Cui, Yu] Hunan Prov Engn Technol Res Ctr Uranium Tailings, Hengyang 421001, Peoples R China.;[Li, Xiangyang] Hunan Prov Engn Res Ctr Radioact Control Technol, Hengyang 421001, Peoples R China.

通讯机构： [Feng, SY; Liu, Y] U;Univ South China, Sch Resource Environm & Safety Engn, Hengyang 421001, Hunan, Peoples R China.

关键词： Discrete fracture network;Fractal dimension;Fractal theory;Radon migration

摘要： A novel model combined with fractal theory and the discrete fracture network (DFN) model is proposed to simulate radon migration in fractured media. In the novel model, the fracture center and length distribution are determined by a first-order model, and the fracture orientations are modeled with the von Mises-Fisher distribution. The model is further developed into a computer software that can calculate the radon diffusion coefficient and exhalation rate of fractured media. An outcrop map is used to validate the ability of the model to describe complex fractures, and radon migration in natural fractures at an outcrop site is predicted using the model. Results show that the model has good reliability and robustness. Evaluation of the representative elementary volume (REV) indicates the existence of REV during the modeling of radon migration in fracture networks. Following an exponential law, REV size decreases with the increase in the length exponent. © 2020

语种： 英文

作者： Chen, Jiaoyan;Yang, Laurence T.;Deng, Xianjun*;Hong, Xianggong;Yi, Lingzhi

期刊： ACM Transactions on Internet Technology,2020年20(3):24:1-24:23 ISSN：1533-5399

通讯作者： Deng, Xianjun

作者机构： [Hong, Xianggong; Chen, Jiaoyan] Nanchang Univ, Sch Informat & Engn, Nanchang 330031, Jiangxi, Peoples R China.;[Yang, Laurence T.] St Francis Xavier Univ, Dept Comp Sci, Antigonish, NS B2G 2W5, Canada.;[Deng, Xianjun] Univ South China, Sch Elect Engn, Hengyang 421001, Hunan, Peoples R China.;[Yi, Lingzhi] Univ South China, Sch Civil Engn, Hengyang 421001, Hunan, Peoples R China.

通讯机构： [Deng, Xianjun] U;Univ South China, Sch Elect Engn, Hengyang 421001, Hunan, Peoples R China.

关键词： K-barrier coverage;minimum receiver problem;Passive bistatic radar network

摘要： The improvement of coverage quality in the construction of multiple-barrier coverage is a critical problem in a wireless sensor network. In this article, we investigate the K-barrier coverage construction problem in passive bistatic radar sensor networks. In contrast to traditional bistatic radar networks, the transmitters in a passive bistatic radar network are predeployed and noncooperative. To construct K barriers, we need to deploy receivers that couple with predeployed transmitters to build continuous barriers. In this work, we focus on the minimum number of receivers problem of constructing K-barrier coverage, where the minimum number of receivers is based on the predeployed transmitters. To handle this problem, we first investigate the optimal placement of receivers between adjacent transmitters for a sub-barrier formation and then determine the optimal placement of receivers for the one-barrier construction. For multiple-barrier coverage construction, we introduce a weighted transmitter graph (WTG) to describe the relation among different transmitters, where the weight in the graph is the minimum number of receivers needed for these two transmitters for a sub-barrier formation. Based on WTG, the minimum receivers problem changes to a problem of how to find K-disjoint paths with the minimum total weight in the graph. For large-scale networks, we also propose two efficient heuristic algorithms to solve the corresponding problem. Finally, we conduct extensive experiments to validate the correctness and the efficiency of the proposed algorithms. © 2020 ACM.

语种： 英文

作者： Dong, Teng;Xie, Shuibo*;Wang, Jingsong;Chen, Zhenfu;Liu, Qing

期刊： Journal of the Australian Ceramic Society,2020年56(1):175-184 ISSN：2510-1560

通讯作者： Xie, Shuibo

作者机构： [Dong, Teng; Wang, Jingsong; Xie, Shuibo; Chen, Zhenfu; Liu, Qing] Univ South China, Sch Civil Engn, Hengyang 421001, Hunan, Peoples R China.;[Dong, Teng; Xie, Shuibo] Univ South China, Sch Resource Environm & Safety Engn, Hengyang 421001, Hunan, Peoples R China.

通讯机构： [Xie, Shuibo] U;Univ South China, Sch Civil Engn, Hengyang 421001, Hunan, Peoples R China.;Univ South China, Sch Resource Environm & Safety Engn, Hengyang 421001, Hunan, Peoples R China.

关键词： Aluminum;Aluminum compounds;Geopolymers;Inorganic polymers;Leaching;Molar ratio;Phosphoric acid;Pore size;Calcined kaolins;Capillary pores;Geopolymer;Geopolymerization;High-humidity environment;Humid environment;Metakaolins;Structural unit;Silicon

摘要： To synthesize a metakaolin phosphate acid-based geopolymer (PAG), calcined kaolin and phosphoric acid solutions with phosphorus-to-aluminium molar ratios (P/Al) of 0.6 to 1.0 were prepared. Fresh PAG was cured in a high-humidity environment at 50°C for 7days. High humidity is helpful for generating AlPO4 during the geopolymerization of PAG. Si and Al are depolymerized from metakaolin upon attack of H3PO4, and the amounts of leached Si and Al are directly proportional to P/Al. Leached Al increases with time, while leached Si decreases and then becomes stable. Pyrophosphate and hexa-coordinate Al could be components of the basic structural unit of PAG. Porosity and cracking increased with increasing P/Al and reduced the strength of PAG. The degree of shrinkage and the pore size are directly proportional to P/Al. The concentrated pores in PAG are gel pores, transitional pores and capillary pores corresponding to different P/Al ratios. © 2019, Australian Ceramic Society.

语种： 英文

作者： Zeng, Sheng;Jiang, Bowei;Sun, Bing

期刊： Geotechnical and Geological Engineering,2019年37(6):5359-5370 ISSN：0960-3182

通讯作者： Sun, Bing(sunbingnh@126.com)

作者机构： [Zeng, Sheng; Jiang, Bowei] School of Resource Environment and Safety Engineering, University of South China, Hengyang;421001, China;[Sun, Bing] School of Civil Engineering, University of South China, Hengyang;[Zeng, Sheng; Jiang, Bowei; Sun, Bing] 421001, China

通讯机构： [Bing Sun] S;School of Civil Engineering, University of South China, Hengyang, China

关键词： Crack propagation;Dynamic deformation;Impact load;Jointed rock mass;Rock mechanics

摘要： A drop hammer impact test on jointed rock masses is carried out in this study. According to the analysis of the effect of different joints on the strength, the deformation and the damage of jointed rock masses, the law of the mechanical properties and crack propagation of jointed rock masses is observed under impact load. First, when the dip angle and the number of the joint are greater, the dynamic bearing capacity of rock masses will be weaker. Meanwhile the deformation and the damage of rock masses will increase. Then, when the impact load is small, the dynamic compression deformation of jointed rock mass is mainly due to the normal closure of joints. After the impact load increased, more microcracks are produced around the joints. These cracks will gradually spread along the joints and finally lead to the damage of jointed rock masses. Besides, the joint can increase the stress waves energy dissipation and weaken the propagation of the stress waves in the rock mass. The study provides a reference for the dynamic analysis of fractured rock masses and the excavation support of surrounding rock mass in deep mining of mines. © 2019, Springer Nature Switzerland AG.

语种： 英文

作者： He, Jia*;Zhang, Xiaoxiong;Dai, Naxin

期刊： Smart Structures and Systems,2019年24(2):209-221 ISSN：1738-1584

通讯作者： He, Jia

作者机构： [He, Jia; Zhang, Xiaoxiong] Hunan Univ, Coll Civil Engn, Changsha, Hunan, Peoples R China.;[He, Jia; Zhang, Xiaoxiong] Hunan Univ, Hunan Prov Key Lab Damage Diag Engn Struct, Changsha, Hunan, Peoples R China.;[Dai, Naxin] Univ South China, Sch Civil Engn, Hengyang, Peoples R China.

通讯机构： [He, Jia] H;Hunan Univ, Coll Civil Engn, Changsha, Hunan, Peoples R China.;Hunan Univ, Hunan Prov Key Lab Damage Diag Engn Struct, Changsha, Hunan, Peoples R China.

关键词： Kalman filter;state estimation;load identification;limited measurements;nonlinear hysteretic structures

摘要： The classical Kalman filter (KF) provides a practical and efficient way for state estimation. It is, however, not applicable when the external excitations applied to the structures are unknown. Moreover, it is known the classical KF is only suitable for linear systems and can't handle the nonlinear cases. The aim of this paper is to extend the classical KF approach to circumvent the aforementioned limitations for the joint estimation of structural states and the unknown inputs. On the basis of the scheme of the classical KF, analytical recursive solution of an improved KF approach is derived and presented. A revised form of observation equation is obtained basing on a projection matrix. The structural states and the unknown inputs are then simultaneously estimated with limited measurements in linear or nonlinear systems. The efficiency and accuracy of the proposed approach is verified via a five-story shear building, a simply supported beam, and three sorts of nonlinear hysteretic structures. The shaking table tests of a five-story building structure are also employed for the validation of the robustness of the proposed approach. Numerical and experimental results show that the proposed approach can not only satisfactorily estimate structural states, but also identify unknown loadings with acceptable accuracy for both linear and nonlinear systems.

语种： 英文