Synthesis of polyethylenimine/graphene oxide for the adsorption of U(VI) from aqueous solution
作者:
Liu, Hongjuan* ;Zhou, Yuancheng;Yang, Yibo;Zou, Ke;Wu, Renjie;...
期刊:
Applied Surface Science ,2019年471:88-95 ISSN:0169-4332
通讯作者:
Liu, Hongjuan;Xie, Shuibo
作者机构:
[Xia, Ke; Liu, Hongjuan; Yang, Yibo; Wu, Renjie; Zhou, Yuancheng; Zou, Ke] Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Peoples R China.;[Xie, Shuibo; Liu, HJ] Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Peoples R China.;[Xie, Shuibo] Univ South China, Hunan Prov Key Lab Pollut Control & Resources Reu, Hengyang 421001, Peoples R China.
通讯机构:
[Liu, HJ; Xie, SB] U;Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Peoples R China.
关键词:
Adsorption;Graphene oxide;Polyethyleneimine;U(VI)
摘要:
Polyethyleneimine (PEI)/graphene oxide (GO) was synthesized through a self-assembly method with the formation of the amide group –CONH– between –NH 2 on PEI and –COOH on GO. The formation was confirmed by Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The oxygen- and nitrogen-containing functional groups of PEI/GO were involved in the adsorption of U(VI), as determined under the FT-IR and XPS analyses of PEI/GO and U(VI)-adsorbed PEI/GO. The pH, contact times, and initial concentration, which are the factors influencing the removal of U(VI), were investigated. The adsorption of U(VI) onto PEI/GO was fitted well with the pseudo-second-order kinetic model and Langmuir isotherm model. The maximum sorption capacities of U(VI) on PEI/GO (145.14 mg·g −1 ) at pH = 7 and T = 303 K were higher than that of U(VI) on GO (94.61 mg·g −1 ). This study provides a novel and simple method for synthesizing GO derivatives with efficient adsorption performances of U(VI) from aqueous solution. © 2018
语种:
英文
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An investigation on physical, mechanical, leaching and radiation shielding behaviors of barite concrete containing recycled cathode ray tube funnel glass aggregate
作者:
Liu, Hualiang;Shi, Jianjun;Qu, Huiqiong;Ding, Dexin*
期刊:
Construction and Building Materials ,2019年201:818-827 ISSN:0950-0618
通讯作者:
Ding, Dexin
作者机构:
[Ding, Dexin; Shi, Jianjun; Liu, Hualiang] Univ South China, Sch Civil Engn, Hengyang 421001, Peoples R China.;[Ding, Dexin; Shi, Jianjun; Liu, Hualiang] Cent S Univ, Sch Resources & Safety Engn, Changsha 410083, Hunan, Peoples R China.;[Ding, Dexin; Qu, Huiqiong] Univ South China, Nucl Resources Engn Coll, Hengyang 421001, Peoples R China.
通讯机构:
[Ding, Dexin] U;Univ South China, Nucl Resources Engn Coll, Hengyang 421001, Peoples R China.
关键词:
Alkali-silica reaction expansion;Barite concrete;Dry shrinkage;Funnel glass;Lead leaching;MCNP;Physical and mechanical behaviors;Radiation shielding;Waste cathode ray tube;XCOM
摘要:
In order to explore the feasibility of using hazardous waste cathode ray tube (CRT) funnel glass to replace high density mineral aggregates in the radiation shielding concrete, various barite concrete samples were prepared with portland cement, ground funnel glass sand as the substitute for barite aggregates, and fly ash as mineral admixtures, and the rates of funnel glass for fine and coarse (5–10 mm) barite aggregate were 25%, 50%, 75%, 100% and 10%, 20%, 30%, respectively. The work performance, mechanical properties, dry shrinkage, alkali-silica reaction (ASR) expansion and lead leaching were investigated, and the γ-ray attenuation coefficients were obtained by experiment, XCOM program and MCNP code. The results show that the slump, ASR expansion and lead leaching of the concrete increase while its apparent density, mechanical properties, dry shrinkage, and γ-ray shielding properties decrease with the increase of the rate of funnel glass. Adding fly ash to the concrete can inhibit the leaching of Pb, and reduce the ASR expansion. The concrete samples with 25–50% fine funnel glass sand or 10–20% 5–10 mm coarse aggregate have good performances. The results show that it's efficient, economical and environmental-benign to use funnel glass to produce the high density radiation shielding concrete. © 2019 Elsevier Ltd
语种:
英文
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Failure behavior of hierarchical corrugated sandwich structures with second-order core based on Mindlin plate theory
作者:
Li, Gang;Li, Zhaokai;Hao, Peng* ;Wang, Yutian;Fang, Yaochu
期刊:
Journal of Sandwich Structures & Materials ,2019年21(2):552-579 ISSN:1099-6362
通讯作者:
Hao, Peng
作者机构:
[Li, Gang; Li, Zhaokai; Hao, Peng; Wang, Yutian] Dalian Univ Technol, Dept Engn Mech, 2 Linggong Rd, Dalian 116024, Liaoning, Peoples R China.;[Fang, Yaochu] Univ South China, Sch Urban Construct, Hengyang, Peoples R China.
通讯机构:
[Hao, Peng] D;Dalian Univ Technol, Dept Engn Mech, 2 Linggong Rd, Dalian 116024, Liaoning, Peoples R China.
关键词:
Failure modes;Finite element method;Sandwich structures;Analytical expressions;Competing failure modes;Corrugated sandwich structures;Corrugated structures;Different structure;Moderately thick plate;Nominal stress;Prediction errors;Mindlin plates
摘要:
For hierarchical corrugated sandwich structures with second-order core, the prediction error of failure behavior by existing methods becomes unacceptable with the increase of structure thickness. In this study, a novel analytical model called moderately thick plate model is developed based on Mindlin plate theory, which can be used to analyze the failure behavior of hierarchical corrugated structures with second-order core under compression or shear loads. Then, the analytical expressions of nominal stress for six competing failure modes are derived based on the moderately thick plate model. The results of six different unit structures based on the moderately thick plate model agree quite well the ones by finite element methods. Furthermore, the influence of different structure thicknesses is investigated to validate the applicability of the moderately thick plate model. According to the comparative results with the thin plate model, the proposed moderately thick plate model has a better precision with the increase of the ratio of thickness to width for failure components. © The Author(s) 2017.
语种:
英文
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氧化石墨烯及其复合材料对水中放射性核素的吸附
作者:
刘红娟;吴仁杰;谢水波;刘迎九
期刊:
材料工程 ,2019年47(10):22-32 ISSN:1001-4381
通讯作者:
Xie, Shui-Bo(xiesbmr@263.net)
作者机构:
[刘红娟; 吴仁杰] Institute of Nuclear Science and Technology, University of South China, Hengyang;Hunan;421001, China;[谢水波] Key Discipline Laboratory for National Defence for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang;[刘迎九] Hunan Province Key Laboratory of Pollution Control and Resources Reuse Technology, University of South China, Hengyang
通讯机构:
[Xie, S.-B.] K;Key Discipline Laboratory for National Defence for Biotechnology in Uranium Mining and Hydrometallurgy, China
关键词:
氧化石墨烯;放射性核素;吸附;改性材料;废水
摘要:
在核能和核技术的快速发展过程及应用中产生了大量放射性废水,其对生态环境会造成潜在的污染,因此对放射性废水处理技术的研究对保护环境有着重要的意义。氧化石墨烯及其复合材料具有比表面积高、官能团丰富、吸附能力强、化学稳定性好等优点,在放射性废水处理领域受到广泛关注。本文综述了近年来有关氧化石墨烯及其复合材料对水中放射性核素吸附的研究现状及进展,介绍了氧化石墨烯及其复合材料对放射性核素的吸附容量、吸附等温模型、吸附热力学、影响因素和吸附机理。最后分析了氧化石墨烯及其复合材料处理放射性核素在辐射稳定性和高吸附选择性等方面面临的问题和挑战,探讨了推动该类材料今后实际放射性废水处理中工程应用的重点研究方向,如完善的产业体系和积极研发相匹配的成套水处理工艺及设备等。
语种:
中文
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废玻璃粉混凝土力学性能研究
作者:
李松;焦楚杰;甘元初
期刊:
工程科学与技术 ,2019年51(5):199-205 ISSN:2096-3246
通讯作者:
Jiao, Chujie(jiaochujie@sina.com)
作者机构:
[李松; 焦楚杰] School of Civil Eng., Guangzhou Univ., Guangzhou;510006, China;[甘元初] School of Civil Eng., Univ. of South China, Hengyang;421001, China;[李松; 焦楚杰] 510006, China
通讯机构:
[Jiao, C.] S;School of Civil Eng., China
关键词:
废玻璃粉混凝土;抗压强度;劈拉强度;弹性模量;泊松比
摘要:
为实现城市固体垃圾废玻璃资源化,以不同掺量废玻璃粉取代水泥,按标准试验方法研究了C30与C50两种强度等级的废玻璃粉混凝土(waste glass powder concrete,WGPC)各类强度变形指标.试验发现:C30WGPC在废玻璃粉掺量在25%~30%之间时,抗压强度同比降低幅度最大,达到了21.7%,C30WGPC替代水泥掺量可在0~25%以内,C50WGPC最佳掺量可大于25%;废玻璃粉的掺入改善了混凝土的脆性性能,随着试配强度等级的提高脆性会有所增大,C50WGPC轴压强度与抗压强度关系式可以近似地进行普通混凝土两者关系的换算;另外,WGPC弹性模量公式适用于计算普通混凝土的弹性模量,WGPC泊松比与普通混凝土泊松比相差不大.试验结果表明废玻璃粉可较大掺量试配强度等级较高的混凝土,并为WGPC的工程应用提供基础参数.
语种:
中文
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Energy Balanced Dispatch of Mobile Edge Nodes for Confident Information Coverage Hole Repairing in IoT
作者:
Deng, Xianjun;Xu, Minliang;Yang, Laurence T.;Lin, Man;Yi, Lingzhi;...
期刊:
IEEE INTERNET OF THINGS JOURNAL ,2019年6(3):4782-4790 ISSN:2327-4662
通讯作者:
Wang, Minghua
作者机构:
[Deng, Xianjun; Xu, Minliang; Wang, Minghua] Univ South China, Dept Commun Engn, Hengyang 421001, Peoples R China;[Yang, Laurence T.; Lin, Man] St Francis Xavier Univ, Dept Comp Sci, Antigonish, NS B2G 2W5, Canada;[Yi, Lingzhi] Univ South China, Sch Civil Engn, Hengyang 421001, Peoples R China
通讯机构:
[Wang, Minghua] U;Univ South China, Dept Commun Engn, Hengyang 421001, Peoples R China.
关键词:
Confident information coverage (CIC);energy balance;hole repairing;Internet of Things (IoT);mobile edge computing (MEC)
摘要:
The promising Internet of Things (IoT) provides a powerful platform for practical smart applications. The limited resources of the IoT nodes as well as the emerged coverage holes pose a great challenge on the quality of service of the IoT. Mobile edge computing (MEC), which can improve the IoT nodes energy consumption efficiency and optimize the utilization effectiveness of the limited resources, provides a novel view for coping with the challenge. Based on the MEC, this paper focuses on how to solve the problem of dispatch of mobile edge nodes for confident information coverage holes repairing (DMEN-CICHR) with the goal of maximizing the network lifetime and guaranteeing the network connectivity. To deal with the DMEN-CICHR problem, we develop an energy-balanced and obstacle-adaptive mobile edge node dispatch algorithm called EBOADMEN-CICHR, which restricts the mobile edge nodes from moving too long distance by setting a bound for each CIC hole and repeatedly updating the bound by a competition mechanism. To guarantee the network connectivity, the EBOADMEN-CICHR recursively performs breadth first search on a constructed undirected graph to find all disconnected subgraphs and then dispatches some mobile edge nodes to connect those disconnected subgraphs until the whole network is connected. A number of experiments emulating the realistic scenarios in radiological pollution monitoring in uranium tailings are executed to verify the effectiveness of the proposed EBOADMEN-CICHR solution. Experimental results show the EBOADMEN-CICHR can perform better than other peer methods in term of higher energy efficiency and longer network lifetime.
语种:
英文
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壳聚糖-生物炭复合材料对U(Ⅵ)的吸附性能试验研究
作者:
高翔;谢水波;刘迎久;曾涛涛;莫官海
期刊:
原子能科学技术 ,2019年53(8):1350-1358 ISSN:1000-6931
通讯作者:
Xie, Shuibo(xiesbmr@263.net)
作者机构:
[高翔; 刘迎久; Zeng, Taotao; 莫官海] School of Civil Engineering, University of South China, Hengyang;421001, China;[谢水波] Hunan Provincial Key Laboratory of Pollution Control and Resources Technology, University of South China, Hengyang;[高翔; 刘迎久; Zeng, Taotao; 莫官海] 421001, China <&wdkj&> Hunan Provincial Key Laboratory of Pollution Control and Resources Technology, University of South China, Hengyang;[高翔; 谢水波; 刘迎久; Zeng, Taotao; 莫官海] 421001, China
关键词:
壳聚糖-生物炭;吸附机理
摘要:
以壳聚糖(CTS)和生物炭(AC)为原料,采用原位沉淀法制备了壳聚糖-生物炭(CTS-AC)复合材料,研究了吸附时间、铀初始浓度、初始pH值、温度和干扰离子等因素对CTS-AC吸附U(Ⅵ)的影响,探讨了CTS-AC对U(Ⅵ)的吸附动力学、等温线,采用傅里叶红外光谱(FT-IR)、X射线衍射(XRD)、扫描电镜(SEM-EDS)及比表面积分析(BET)等手段进行了相关机理分析。实验结果表明,CTS-AC吸附U(Ⅵ)的最佳条件为:pH=4、CTS-AC投加量0.8~1g/L、吸附时间240min,在此条件下,最大吸附率可达94.85%。CTS-AC对U(Ⅵ)的吸附等温线模型符合Langmuir模型,U(Ⅵ)的吸附动力学符合准二级模型;高浓度Cu~(2+)对CTS-AC吸附U(Ⅵ)的抑制作用明显;FT-IR、XRD和EDS结果表明,CTS的负载未改变AC的原结构,仅增大了其孔径、增加了结合位点。CTS-AC对U(Ⅵ)的吸附机制为配位作用以及离子交换。
语种:
中文
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The study of migration velocity of Cs-135 and Se-79 in intact rock(Open Access)
作者:
H LING;L CHEN;W M CHEN;L YUN
期刊:
IOP Conference Series: Materials Science and Engineering ,2019年592(1):371-377 ISSN:1757-8981
作者机构:
[L YUN; W M CHEN; H LING; L CHEN] Beijing Research Institute of Uranium Geology, CNNC, Beijing, 100029, China;[H LING] Hunan Provincial Key Laboratory of Pollution Control and Resources Technology, University of South China, Hengyang, 421001, China
会议名称:
第二届制造技术,材料和化学工程国际学术会议(MTMCE 2019)
会议时间:
2019-06-14
会议地点:
中国湖北武汉
会议论文集名称:
Proceedings of 2019 2nd International Conference on Manufacturing Technology, Materials and Chemical Engineering (MTMCE 2019)
摘要:
The migration characteristics of highly mobile nuclides in natural barrier are the key concerns in the long-term safety assessment of geological disposal facilities. This paper focused on typical granite in Beishan area for geological disposal of high-level radioactive waste, and established a computational model for the release and migrate of nuclides after closure of repository by GoldSim. The migration characteristics of Cs-135 and Se-79 were analyzed by Monte Carlo stochastic simulation. The results show that the migration characteristics of Cs-135 and Se-79 in intact rock are direct influenced by hydraulic conductivity and hydraulic gradient, the migration velocity are 2.47×10<sup>-4</sup>m/a and 9.61×10<sup>-4</sup>m/a when the hydraulic conductivity correspond to 5.74 ×10<sup>-9</sup> m/s. The analysis of the results shows that the migration characteristics can provide feedback guidance for the site selection and design of the disposal repository.<br/> ©Published under licence by IOP Publishing Ltd.
语种:
英文
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磁性介孔TiO_2/氧化石墨烯复合材料的制备及其对U(Ⅵ)的吸附
作者:
毕玉玺;凌辉;唐振平;谢严兴
期刊:
复合材料学报 ,2019年36(9):2176-2186 ISSN:1000-3851
通讯作者:
Tang, Zhenping(1578988350@qq.com)
作者机构:
[毕玉玺; 唐振平; 谢严兴] Hunan Provincial Key Laboratory of Pollution Control and Resources Technology, University of South China, Hengyang;421001, China;[凌辉] CNNC, Beijing Research Institute of Uranium Geology, Beijing;100029, China;[毕玉玺; 唐振平; 谢严兴] 421001, China
通讯机构:
[Tang, Z.] H;Hunan Provincial Key Laboratory of Pollution Control and Resources Technology, China
关键词:
氧化石墨烯(GO);磁性介孔TiO2;吸附;解吸;共存离子
摘要:
以氧化石墨烯(GO)、纳米Fe_3O_4、钛酸四丁酯(TBOT)为原料,合成了磁性介孔TiO_2/GO(Fe_3O_4 @TiO_2/GO)复合材料,用其处理浓度为10mg·L~(-1)的含U(Ⅵ)废水。研究了Fe_3O_4@TiO_2/GO复合材料中GO含量、溶液初始pH值、Fe_3O_4@TiO_2/GO复合材料投加量、反应时间、U(Ⅵ)初始浓度及共存离子对U(Ⅵ)吸附的影响。结果表明:在pH值为6、GO质量分数为60wt%、Fe_3O_4@TiO_2/GO复合材料投加量为10mg的条件下, Fe_3O_4@TiO_2/GO复合材料对U(Ⅵ)的吸附效果最佳,较同等条件下磁性介孔Fe_3O_4@TiO_2复合材料和GO的吸附量分别高了10.99mg·g~(-1)和1.91mg·g~(-1)。Fe_3O_4@TiO_2/GO复合材料对U(Ⅵ)的吸附180min即达到平衡,准二级动力学模型和Freundlich吸附等温模型能很好地描述其吸附过程。解吸实验表明,经5次吸附-解吸后, U(Ⅵ)的吸附率仍高达90.86%,说明Fe_3O_4@TiO_2/GO复合材料具有较高的循环利用性能。
语种:
中文
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Wind driven “pumping” fluid flow and turbulent mean oscillation across high-rise building enclosures with multiple naturally ventilated apertures
作者:
Zhong, Huai-Yu;Zhang, Dong-Dong;Liu, Yang;Liu, Di;Zhao, Fu-Yun* ;...
期刊:
Sustainable Cities and Society ,2019年50:101619 ISSN:2210-6707
通讯作者:
Zhao, Fu-Yun
作者机构:
[Zhong, Huai-Yu; Zhao, Fu-Yun; Liu, Yang; Zhang, Dong-Dong] Wuhan Univ, Minist Educ, Key Lab Hydraul Machinery Transients, Wuhan, Hubei, Peoples R China.;[Zhong, Huai-Yu; Zhao, Fu-Yun; Liu, Yang; Zhang, Dong-Dong] Wuhan Univ, Hubei Key Lab Waterjet Theory & New Technol, Wuhan, Hubei, Peoples R China.;[Zhong, Huai-Yu; Zhao, Fu-Yun; Liu, Yang; Zhang, Dong-Dong] Wuhan Univ, Sch Power & Mech Engn, Dong Hu Southern Rd, Wuhan 430072, Hubei, Peoples R China.;[Liu, Di] China Univ Petr, Coll Pipeline & Civil Engn, Qingdao, Shandong, Peoples R China.;[Li, Yuguo] Univ Hong Kong, Dept Mech Engn, Pokfulam Rd, Hong Kong, Peoples R China.
通讯机构:
[Zhao, Fu-Yun] W;Wuhan Univ, Sch Power & Mech Engn, Dong Hu Southern Rd, Wuhan 430072, Hubei, Peoples R China.
关键词:
Contaminant dispersion;Full CFD simulation;Single-sided ventilation;Vortex shedding
摘要:
This paper presents a study on the impact of incoming wind velocity magnitudes and horizontal aperture separations on natural ventilation flows in a single-sided wind-driven naturally ventilated building with two apertures (SS2) on the rear wall or the front wall. Both the velocity fields and the contaminant concentration fields were simulated and investigated. The present study is based on CFD simulations with unsteady Reynolds-averaged Navier-Stokes (URANS) SST k-ω model. A vortex shedding flow mechanism has been identified when the two apertures are mounted either on the rear wall or on the front wall, through which the air flow oscillates at a certain rate. CFD results further demonstrate that the oscillating frequency increases with the incoming wind magnitude and is nearly independent of the horizontal aperture separations. For the same building configuration, the root mean square (r.m.s) of the non-dimensional ventilation flow rate is independent of the incoming wind speed, whereas it decreases when the horizontal aperture separation is reduced. The time-averaged contaminant concentration fields also validated the different ventilation performance of different aperture configurations. This novel ventilation mechanism could be applied to alleviate the poor ventilation performance of buildings with single-sided apertures.
语种:
英文
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Thermal driven flows inside a square enclosure saturated with nanofluids: Convection heat functions and transfer rate revisions from a homogenous model
作者:
Wang, Lei;Zhang, Dong-Dong;Zhao, Fu-Yun* ;Liu, Di;Wang, Han-Qing
期刊:
Numerical Heat Transfer, Part B: Fundamentals ,2019年75(4):265-288 ISSN:1040-7790
通讯作者:
Zhao, Fu-Yun
作者机构:
[Wang, Lei; Zhang, Dong-Dong; Zhao, Fu-Yun] Wuhan Univ, Minist Educ, Key Lab Hydraul Machinery Transients, Wuhan, Hubei, Peoples R China;[Wang, Lei; Zhang, Dong-Dong; Zhao, Fu-Yun] Wuhan Univ, Hubei Key Lab Waterjet Theory & New Technol, Wuhan, Hubei, Peoples R China;[Wang, Lei; Zhang, Dong-Dong; Zhao, Fu-Yun] Wuhan Univ, Sch Power & Mech Engn, 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, Wuhan 430072, Hubei, Peoples R China.
关键词:
Deterioration;Enclosures;Excitons;Heat convection;Heat transfer performance;Nanoparticles;Thermal conductivity;Homogenous models;Numerical investigations;Numerical results;Rayleigh number;Square enclosures;Theoretical research;Thermal carriers;Transfer rates;Nanofluidics
摘要:
In former theoretical researches of nanofluid flows, numerical investigations could not agree with experimental observations, particularly regarding whether the mixing nanoparticles will enhance or deteriorate the heat transfer. In the present work, thermal driven buoyancy flows of nanofluids in a square enclosure were modeled by the use of homogeneous assumptions and the effective kinematic viscosity and thermal conductivity formulas. Thoroughly developed heat transfer coefficient is subsequently proposed, aiming to critically evaluate the performance of nanofluid heat transport. Numerical results are presented over a wide range of thermal Rayleigh number (10(3) <= Ra <= 10(6)) and nanoparticles volume fraction (0.001 <= phi <= 0.04). Present modeling results accurately predict both the enhancement and deterioration of the natural convection heat transfer, fully validated by former experimental observations. Overall, mathematical models and Nusselt number definitions proposed in the present work effectively enhance the reliability of numerical modeling researches on the nanofluid heat transfer. Present clarification research on the Nusselt unifications could benefit future development of thermal carrier fluid enhanced by nano-particles.
语种:
英文
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Sulfate attack resistance of sustainable concrete incorporating various industrial solid wastes
作者:
Tang, Zhuo;Li, Wengui* ;Ke, Guojun;Zhou, John L.;Tam, Vivian W. Y.
期刊:
Journal of Cleaner Production ,2019年218:810-822 ISSN:0959-6526
通讯作者:
Li, Wengui
作者机构:
[Tang, Zhuo; Li, Wengui; Zhou, John L.] Univ Technol Sydney, Ctr Built Infrastruct Res, Sch Civil & Environm Engn, Sydney, NSW 2007, Australia.;[Ke, Guojun] Univ South China, Sch Civil Engn, Hengyang 421001, Hunan, Peoples R China.;[Tam, Vivian W. Y.] Western Sydney Univ, Sch Comp Engn & Math, Penrith, NSW 2751, Australia.
通讯机构:
[Li, Wengui] U;Univ Technol Sydney, Ctr Built Infrastruct Res, Sch Civil & Environm Engn, Sydney, NSW 2007, Australia.
关键词:
Compressive strength;Concretes;Durability;Fly ash;Glass;Minerals;Portland cement;Sodium sulfate;Solid wastes;Tensile strength;Coal gangues;Environmental problems;Industrial solid wastes;Splitting tensile strength;Sulfate-attack resistances;Sustainable concretes;Ultrasonic pulse velocity;Waste glass powder;Sulfur compounds
摘要:
Industrial solid wastes are inducing severe environmental problems, but the problem can be overcame by reusing them as construction materials. The sulfate resistances of sustainable concrete incorporating various solid waste materials, including waste glass powder (WGP), coal gangue powder (CGP) and fly ash (FA) were investigated in this study. Concrete mixes with different water to binder (w/b) ratios and containing various solid waste materials as partial replacement of Portland cement by ratios of 10%, 20%, and 30% were prepared. These mixes were immersed in the 5% Na 2 SO 4 solution for a total period of 22 months. The sulfate attack resistances were evaluated extensively based on visual appearance, mass change, compressive strength, splitting tensile strength, ultrasonic pulse velocity, mineralogy, and microstructure. The results indicate that regardless of the type and content of solid waste materials, the replacement of cement by solid waste materials exhibit a positive impact on the sulfate attack resistance. Under the same substitution level, WGP appear to be the most effective in offsetting the destructive effect of sulfate attack, followed by CGP and FA. Therefore, sustainable concrete incorporating solid waste materials can not only promote the recycling of solid waste, but also provide high sulfate attack resistance. © 2019 Elsevier Ltd
语种:
英文
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Dynamic responses of high-speed railway transition zone with various subgrade fillings
作者:
Hu, Ping;Zhang, Chunshun* ;Wen, Sen;Wang, Yonghe
期刊:
Computers and Geotechnics ,2019年108:17-26 ISSN:0266-352X
通讯作者:
Zhang, Chunshun
作者机构:
[Hu, Ping] Univ South China, Sch Civil Engn, Hengyang 421001, Peoples R China.;[Zhang, Chunshun; Hu, Ping] Monash Univ, Dept Civil Engn, Melbourne, Vic 3800, Australia.;[Wen, Sen] Henan Univ, Sch Civil Engn & Architecture, Kaifeng 475004, Peoples R China.;[Wang, Yonghe] Cent S Univ, Sch Civil Engn, Changsha 410075, Hunan, Peoples R China.
通讯机构:
[Zhang, Chunshun] M;Monash Univ, Dept Civil Engn, Melbourne, Vic 3800, Australia.
关键词:
Dynamic analysis;High-speed railway;Subgrade fillings;Transition zone
摘要:
In order to explore more economic filling alternatives than typically used graded gravel + 5% cement in a high-speed railway transition zone, engineering properties of graded gravel (without cement) and A, B group filling (well graded coarse-grained soil with less than 30% of fine-grained soil) were tested. This is followed by the establishment of a 3D vertical coupling dynamic model of a tunnel-culvert-tunnel transition section based on the D'Alembert's principle of energy weak variation and the Lagrange scheme. The model results have been validated against the in situ measurements. The analysis from the model show that both graded gravel and A, B group filling are well-graded with high strengths, and the dynamic responses of the roadbed supported by the two fillings are both less than allowable values at the speed of 350 km/h. However, the curves of vertical displacement along the longitudinal transition section are great like a shape of “W” with the A, B group filling in the transition zone. Therefore, the graded gravel is recommended to be more suitable than the A, B group filling for the studied tunnel-culvert-tunnel transition zone. This recommendation may be applicable to the case with a rock subgrade underneath to support the transition zone. Comparatively, for a soil subgrade under the transition zone, our results indicate that graded gravel + 5% cement is still the best filling material, while the other two less stiffer filling materials would result in considerable fluctuations to the roadbed surface. © 2018 Elsevier Ltd
语种:
英文
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A Wind-Driven Gas Exchange Rate Model
作者:
Duan, Zhiyong*
期刊:
ENVIRONMENTAL ENGINEERING SCIENCE ,2019年36(3):344-349 ISSN:1092-8758
通讯作者:
Duan, Zhiyong
作者机构:
[Duan, Zhiyong] Univ South China, Sch Civil Engn, Hengyang 421000, Hunan, Peoples R China.
通讯机构:
[Duan, Zhiyong] U;Univ South China, Sch Civil Engn, Hengyang 421000, Hunan, Peoples R China.
关键词:
gas exchange rate;water quality modeling;wind-driven
摘要:
The dissolved oxygen is a major factor influencing the water quality of a water body. The gas exchange rate determines the speed that the low soluble gases, including dissolved oxygen, transfer from atmosphere to water. The wind-driven gas exchange rate model is important for the water quality modeling in water bodies such as lakes and estuaries when the wind is the predominant factor. Although empirical formulae have been developed for wind-driven gas exchange rate, they cannot explain the mechanisms of wind-driven gas exchange rate. The empirical formulae are normally limited in their applicability due to the specific experimental conditions under which they were established. This study is to develop a mechanistic wind-driven gas exchange rate model for the general application ranges. This mechanistic wind-driven gas exchange rate model correlates the gas exchange rate with the hydrodynamic parameters based on the surface renewal mechanism and the two-film transfer mechanism. The gas exchange rate values predicted with this model show reasonable agreements with the experimental data in the wind-driven gas exchange systems. This model can be applied for water bodies with wind blowing over the water surface as the predominant factor influencing the exchange rate of the low soluble gases. © 2019 Mary Ann Liebert, Inc., publishers.
语种:
英文
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Airborne pollutant dilution inside the deep street canyons subjecting to thermal buoyancy driven flows: Effects of representative urban skylines
作者:
Mei, Shuo-Jun;Hu, Jiang-Tao;Liu, Di* ;Zhao, Fu-Yun* ;Li, Yuguo;...
期刊:
Building and Environment ,2019年149:592-606 ISSN:0360-1323
通讯作者:
Zhao, Fu-Yun;Liu, Di
作者机构:
[Hu, Jiang-Tao; Zhao, Fu-Yun; Mei, Shuo-Jun] Wuhan Univ, Key Lab Hydraul Machinery Transients, Minist Educ, Wuhan, Hubei, Peoples R China.;[Hu, Jiang-Tao; Zhao, Fu-Yun; Mei, Shuo-Jun] Wuhan Univ, Shenzhen Res Inst, Shenzhen, Guangdong, Peoples R China.;[Hu, Jiang-Tao; Zhao, Fu-Yun; Mei, Shuo-Jun] 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.;[Li, Yuguo] Univ Hong Kong, Dept Mech Engn, Pokfulam Rd, Hong Kong, Peoples R China.
通讯机构:
[Zhao, Fu-Yun] W;[Liu, Di] C;Wuhan Univ, Sch Power & Mech Engn, Dong Hu South Rd, Wuhan 430072, Hubei, Peoples R China.;China Univ Petr, Coll Pipeline & Civil Engn, Qingdao, Shandong, Peoples R China.
关键词:
Pollutant retention time;Thermal boundary layer flows;Thermal plume merging;Thermally-driven canyon ventilation;Urban morphology
摘要:
The air flow and pollutant dispersion within a group of street canyons ventilated merely by thermal buoyancy force induced by heated building surfaces are examined by CFD model using SST k-ω turbulence model for different urban skyline configurations. Pollutants emitted from the bottom of street canyon roughly mimic the traffic exhaust releasing. Numerical results are validated well with former theoretical results on thermal boundary flow adjacent to a heated vertical wall. The air exchange rate per hour (ACH) and pollutant retention time are adopted to evaluate the canyon ventilation performance. An exponential relationship could be established between the pollutant retention time and the thermal boundary flow rate. A semi-empirical formula is proposed by using the theoretical results of thermal boundary layer and two empirical constants derived from the present simulation results, which could be used to evaluate the ventilation performance at the urban design. As the convergence flow at the street canyon roof decays from urban rim to urban center, the pollutant retention time differs from canyon to canyon. The 'protuberant' skyline configuration is found more effectively in purifying the street canyons at urban edge, in contrast, the 'concave' skyline configuration shows higher purification efficiency at urban center. Present research could benefit for design purpose and environmental impact assessment. © 2018 Elsevier Ltd
语种:
英文
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Bonded Sleeve Connections for Joining Tubular Glass Fiber-Reinforced Polymer Beams and Columns: Experimental and Numerical Studies
作者:
Zhang, Zhu Jing;Bai, Yu* ;Xiao, Xiao
期刊:
Journal of Composites for Construction ,2018年22(4) ISSN:1090-0268
通讯作者:
Bai, Yu
作者机构:
[Bai, Yu; Zhang, Zhu Jing] Monash Univ, Dept Civil Engn, Clayton, Vic 3800, Australia.;[Xiao, Xiao] Univ South China, Sch Civil Engn, Hengyang 421001, Hunan, Peoples R China.
通讯机构:
[Bai, Yu] M;Monash Univ, Dept Civil Engn, Clayton, Vic 3800, Australia.
关键词:
Bolts;Fiber reinforced plastics;Finite element method;Glass fibers;Joining;Pultrusion;Reinforced plastics;Reinforcement;Steel beams and girders;Stiffness;Tubular steel structures;Adhesive bonding;Beam - column connection;Bolted connections;Fiber reinforced composites;Sleeve connections;Tubular members;Fiber bonding
摘要:
A bonded sleeve connection was developed for joining tubular glass fiber-reinforced polymer (GFRP) beams and columns. It utilizes a sleeve connector made by welding a steel tube to a steel endplate. The steel tube is then inserted into and adhesively bonded with the GFRP beam end and the endplate is connected to the GFRP column using through-bolts. Four beam-to-column specimens with different bond lengths between the GFRP beam and steel tube and different numbers of bolts were tested. The moment-rotation responses, failure modes, and local strain responses were experimentally received and comparatively studied. The measured initial rotational stiffness of the proposed bonded sleeve connections was evaluated against a standard classification and compared to existing connection systems. Numerical analysis was also performed through finite element (FE) modeling. Paired contact elements and pretension elements were used to model the bolted connections, taking into account effects of friction, pretension force, and bolt hole clearance. Relevant failure criteria were also used to indicate yielding of the steel endplate and cohesive failure. Modeling and experimental results compared well in terms of moment-rotation behavior and failure modes. Further parametric study evidenced dominant effects of endplate thickness on the initial rotational stiffness of the connections. © 2018 American Society of Civil Engineers.
语种:
英文
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Thermal buoyancy driven flows inside the industrial buildings primarily ventilated by the mechanical fans: Local facilitation and infiltration
作者:
Mei, Shuo-Jun;Hu, Jiang-Tao;Liu, Di* ;Zhao, Fu-Yun* ;Wang, Han-Qing
期刊:
Energy and Buildings ,2018年175:87-101 ISSN:0378-7788
通讯作者:
Zhao, Fu-Yun;Liu, Di
作者机构:
[Hu, Jiang-Tao; Zhao, Fu-Yun; Mei, Shuo-Jun] Wuhan Univ, Key Lab Hydraul Machinery Transients, Minist Educ, Wuhan, Hubei, Peoples R China.;[Hu, Jiang-Tao; Zhao, Fu-Yun; Mei, Shuo-Jun] Wuhan Univ, Hubei Key Lab Waterjet Theory & New Technol, Wuhan, Hubei, Peoples R China.;[Hu, Jiang-Tao; Zhao, Fu-Yun; Mei, Shuo-Jun] Wuhan Univ, Sch Power & Mech Engn, 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;[Liu, Di] C;Wuhan Univ, Sch Power & Mech Engn, Wuhan 430072, Hubei, Peoples R China.;China Univ Petr, Coll Pipeline & Civil Engn, Qingdao, Shandong, Peoples R China.
关键词:
Local ventilated cooling;Mechanical assisted natural ventilation;Natural ventilation of industrial buildings;On-site measurements
摘要:
The turbine hall houses a number of components with intense heat release, resulting in a hot and humid air environment and making it very unpleasant for plant staffs to conduct maintenance work there, particularly at a hot outdoor environment. The traditional pure buoyancy driven natural ventilated could fulfil the overall heat exhausting requirement, however, creating hot environment at several positions due to the vortex airflow structure. As only part of the building need to be cooled, a localized cooling system with assisting mechanical fans is used. Buoyancy driven natural ventilated flows primarily occupying this turbine hall have been investigated by a computational fluid dynamics (CFD) model and an on-site measurement. The ventilation airflow is solved by 3D steady state Reynolds Averaged Navier-Stokes (RANS) equations in conjunction with the SST k-ω turbulence model. The numerical codes and procedures were validated by comparing with on-site measurements. The concept of mean age of air is used to evaluate the natural ventilated efficacy. Following that, the potential of using mechanical vents and slabs to cool equipment work area at this buoyancy driven natural ventilated hall is analysed. The simulation results show that the mechanical vents could decrease air temperature and increase air exchange efficiency at work area effectively on condition that the local airflow pattern is well organized, which is strongly related to the ejection direction and velocity. Present research could benefit future development of the ventilation design in the power plant buildings.
语种:
英文
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Improving Anaerobic Digested Sludge Dewaterability through Gamma-Ray Irradiation and Struvite Precipitation
作者:
Wu, Yuqi;Jiang, Yinghe* ;Ke, Guojun
期刊:
Journal of Environmental Engineering ,2018年144(2) ISSN:0733-9372
通讯作者:
Jiang, Yinghe
作者机构:
[Jiang, Yinghe; Wu, Yuqi] Wuhan Univ Technol, Sch Civil Engn & Architecture, Wuhan 430070, Hubei, Peoples R China.;[Wu, Yuqi; Ke, Guojun] Univ South China, Sch Civil Engn, Hengyang 421001, Peoples R China.
通讯机构:
[Jiang, Yinghe] W;Wuhan Univ Technol, Sch Civil Engn & Architecture, Wuhan 430070, Hubei, Peoples R China.
关键词:
Gamma rays;Irradiation;Nitrogen;Nitrogen compounds;Precipitation (chemical);Sludge digestion;Wastewater treatment;Dewaterability;Digested sludges;Gamma-ray irradiation;Magnesium ammonium phosphates;Solid liquid separation;Struvite precipitation;Struvites;Wastewater treatment plants;Anaerobic digestion;ammonium;anaerobic digestion;dewatering;exopolymer;gamma ray radiation;irradiation;lysis;microbial activity;nitrogen;orthophosphate;phosphorus;precipitation (chemistry);sludge;struvite;wastewater treatment;wastewater treatment plant
摘要:
Anaerobic digestion is a generally used microbial process in wastewater treatment plants, and anaerobic digestion sludge often possesses unacceptable characteristics including high resistance to solid-liquid separation and high concentration of nutrients, such as phosphorus and nitrogen. Gamma-ray irradiation was used to improve the dewaterability of anaerobic digestion sludge, and the struvite (magnesium ammonium phosphate) precipitation method was utilized to recover increased orthophosphate (PO43 - P) and ammonium nitrogen (NH4+-N) from the postirradiation liquor. An absorbed dose of 5-15 kGy would be potentially successful for dewaterability improvement, and the optimal dewaterability occurred at 10 kGy, which could reduce the water content of sludge cake from 80.08 to 73.46%. The mechanism for the enhanced dewaterability was also analyzed, and the lysis of extracelluar polymeric substances and reduction of particle surface charges were found to be the major reasons. Furthermore, the recovery rate of PO43 - P and NH4+-N were 86.07 and 15.08%, respectively, under the condition of Mg/P of 1.8 (molar ratio), pH 9.6, and reaction time of 30 min. © 2017 American Society of Civil Engineers.
语种:
英文
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Uniformity of thermal fields in multi-heat-sources synthesis and the elongations of graphene sheets composites and polymers applied in the Bionic robots
作者:
Zhang, Dong-Dong;Wang, Xin;Liu, Di;Zhao, Fu-Yun* ;Xue, Long-Jian;...
期刊:
Applied Thermal Engineering ,2018年129:354-365 ISSN:1359-4311
通讯作者:
Zhao, Fu-Yun
作者机构:
[Xue, Long-Jian; Zhao, Fu-Yun; Wang, Xin; Zhang, Dong-Dong] Wuhan Univ, Minist Educ, Key Lab Hydraul Machinery Transients, Wuhan, Hubei, Peoples R China.;[Xue, Long-Jian; Zhao, Fu-Yun; Wang, Xin; Zhang, Dong-Dong] Wuhan Univ, Hubei Key Lab Waterjet Theory & New Technol, Wuhan, Hubei, Peoples R China.;[Xue, Long-Jian; Zhao, Fu-Yun; Wang, Xin; Zhang, Dong-Dong] Wuhan Univ, Sch Power & Mech Engn, Dong Hu Southern 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 Southern Rd, Wuhan 430072, Hubei, Peoples R China.
关键词:
Experimental validation;Graphene sheets/polymer composites;Heat transfer model;Soft robots
摘要:
A three-dimensional heat transfer numerical model is proposed here for the soft-body caterpillar-like robots to present insights for biologists and engineers understanding heat-induced locomotion of these robots. Thermal field distribution of the soft robot body made by the polymer composites is firstly modeled by the use of computational fluid dynamic methodology. The computed spatial distributions of thermal fields were subsequently compared with experimental ones. The achieved agreement between numerical and experimental results further validated the numerical methodology well. Uniformity of thermal field, uniformity factors and typical temperatures for the soft robot body are numerically calculated in details. The results demonstrated that power density P, body size W and thermal conductivity (graphite content) κr have significant effects in the spatial distributions of heat transfer. Furthermore, the specific volume ratio and optimal structural configuration of the heating sources (GS composites: graphene sheets and pliable polydimethylsiloxane) and substrates (pure PDMS: polydimethylsiloxane) are determined upon that the maximum elongation is achieved at different operation conditions of P, W and κr respectively. Present research could contribute to the remotely powered and controlled soft robots made by polymer composites. © 2017
语种:
英文
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Room airborne pollutant separation by the use of air curtains in the large building enclosure: Infiltration efficiency and partial enclosure ventilation rate
作者:
Zhao, Fu-Yun* ;Shen, Guang;Liu, Ke-Jun;Xu, Ying;Liu, Di;...
期刊:
Journal of Building Engineering ,2018年18:386-394 ISSN:2352-7102
通讯作者:
Zhao, Fu-Yun
作者机构:
[Shen, Guang; Zhao, Fu-Yun; Xu, Ying; Liu, Ke-Jun] Hunan Univ Technol, Sch Civil Engn, Taishan Rd, Zhuzhou 412007, Hunan, Peoples R China.;[Zhao, Fu-Yun] Wuhan Univ, Sch Power & Mech Engn, Wuhan, Hubei, Peoples R China.;[Liu, Di] China Univ Petr, Coll Pipeline & Civil Engn, Qingdao, Shandong, Peoples R China.;[Wang, Han-Qing; Zhao, Fu-Yun] Univ South China, Sch Civil Engn, Hengyang, Hunan, Peoples R China.
通讯机构:
[Zhao, Fu-Yun] H;Hunan Univ Technol, Sch Civil Engn, Taishan Rd, Zhuzhou 412007, Hunan, Peoples R China.
关键词:
Air curtains;Conservation;Efficiency;Enclosures;Flow of fluids;Linear regression;Pollution;Airborne pollutants;Computational analysis;Conservation equations;Multiple linear regression analysis;Multiple linear regressions;Pollutant dispersions;Species concentration;Species transport;Air
摘要:
Suppression of airborne pollutant infiltration into the occupation region by the air curtain was numerically studied in the present work. The computational analysis was depending on the two-dimensional conservation equations of mass, momentum and species concentration for the incompressible isothermal turbulent flow with a standard k-ε two-equation turbulent model adopted for turbulence closure. Time averaged turbulent stream-functions and species-functions were respectively defined to vividly visualize the fluid flow and pollutant dispersion. The effects of ejection velocity, air curtain width and enclosure height on the turbulent fluid flow and the sealing performance of the air curtain were investigated. Detailed correlations of air curtain sealing efficiency with those governing parameters were presented through multiple linear regression analysis. Numerical results indicate that air curtain sealing efficiency is heavily influenced by the enclosure height, while little by the air curtain width. Present investigation could benefit the future development of air curtain implemented in the control of airborne pollutant dispersion in the large building spaces. © 2018 Elsevier Ltd
语种:
英文
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