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Enhanced properties of stone coal-based composite phase change materials for thermal energy storage

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International Journal of Minerals,Metallurgy and Materials 2024年第1期31卷 206-215页

作者： Baoshan Xie Huan Ma Chuanchang Li Jian Chen Key Laboratory of Renewable Energy Electric-technology of Hunan Province School of Energy and Power EngineeringChangsha University of Science and TechnologyChangsha 410114China State Key Laboratory of disaster prevention and Reduction for Power Grid Changsha University of Science and TechnologyChangsha 410114China

Phase change materials (PCMs) can be incorporated with low-cost minerals to synthesize composites for thermal energy storage in building applications.Stone coal (SC) after vanadium extraction treatment shows potential for secondary utilization in composite preparation.We prepared SC-based composite PCMs with SC as a matrix,stearic acid (SA) as a PCM,and expanded graphite (EG) as an additive.The combined roasting and acid leaching treatment of raw SC was conducted to understand the effect of vanadium extraction on promoting loading capacity.Results showed that the combined treatment of roasting at 900℃ and leaching increased the SC loading of the composite by 6.2%by improving the specific surface area.The loading capacity and thermal conductivity of the composite obviously increased by 127%and 48.19%,respectively,due to the contribution of 3wt% EG.These data were supported by the high load of 66.69%and thermal conductivity of 0.59 W·m^(-1)·K-1of the designed composite.The obtained composite exhibited a phase change temperature of 52.17℃,melting latent heat of 121.5 J·g^(-1),and good chemical compatibility.The SC-based composite has prospects in building applications exploiting the secondary utilization of minerals.

关键词： thermal energy storage phase change material stone coal vanadium extraction secondary utilization

Explosion resistance performance of reinforced concrete box girder coated with polyurea:Model test and numerical simulation

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Defence technology（防务技术） 2024年第3期33卷 1-18页

作者： Guangpan Zhou Rong Wang Mingyang Wang Jianguo Ding Yuye Zhang School of science Nanjing University of Science and TechnologyNanjing 210094JiangsuChina School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094JiangsuChina State Key Laboratory of Explosion and Impact and disaster prevention and Mitigation Army Engineering University of PLANanjing 210007JiangsuChina

To study the anti-explosion protection effect of polyurea coating on reinforced concrete box girder,two segmental girder specimens were made at a scale of 1:3,numbered as G(without polyurea coating)and PCG(with polyurea coating).The failure characteristics and dynamic responses of the specimens were compared through conducting explosion tests.The reliability of the numerical simulation using LS-DYNA software was verified by the test results.The effects of different scaled distances,reinforcement ratios,concrete strengths,coating thicknesses and ranges of polyurea were studied.The results show that the polyurea coating can effectively enhance the anti-explosion performance of the girder.The top plate of middle chamber in specimen G forms an elliptical penetrating hole,while that in specimen PCG only shows a very slight local dent.The peak vertical displacement and residual displacement of PCG decrease by 74.8% and 73.7%,respectively,compared with those of specimen G.For the TNT explosion with small equivalent,the polyurea coating has a more significant protective effect on reducing the size of fracture.With the increase of TNT equivalent,the protective effect of polyurea on reducing girder displacement becomes more significant.The optimal reinforcement ratio,concrete strength,thickness and range of polyurea coating were also drawn.

关键词： Explosive load Explosion resistance performance Model test Polyurea Concrete box girder Numerical simulation

Preparation and Swelling Kinetic Analysis of Poly (HPMC-co-AA-co-AM) Super Absorbent Resin

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Journal of Wuhan University of technology(Materials science) 2024年第3期39卷 790-799页

作者：马砺 WANG Xin LIU Xixi WEI Gaoming GUO Ying School of Safety science and Engineering Xi’an University of Science and TechnologyXi'an 710054China Key Laboratory of Coal Fire disaster prevention Xi’an University of Science and TechnologyXi'an 710054China School of Energy Engineering Xi’an Uni-versity of Science and TechnologyXi'an 710054China Yanzhou Coal Mining Co. Ltd.Zoucheng 237500China

Super absorbent resin(SAR)is prepared by aqueous high temperature polymerization using hydroxypropyl methylcellulose(HPMC)as monomer backbone material,acrylic acid(AA)and acrylamide(AM)as the graft copolymer monomer,potassium persulfate(KPS)as the initiator to generate free radicals,and N,N`-methylenebisacrylamide(MBA)as cross-linking agent for cross-linking reaction.Simutaneously,the influence of individual factors on the water absorption is investigated,and these factors are mainly AA,AM,KPS,MBA,HPMC,and reaction temperature.The optimized conditions are obtained by the experiment repeating for several times.The water absorption multiplicity and salt absorption multiplicity under the conditions are 782.4 and 132.5 g/g,respectivity.Furthermore,the effects of different temperatures and salt concentrations on its water absorption,as well as the swelling kinetics of SAR are studied.It is indicated the water-absorbing swelling process is mainly caused by the difference in water osmotic pressure and Na+concentration inside and outside the cross-linked molecular structure of the resin,which is not only consistent with the quasi-secondary kinetic model,but also with the Fick diffusion model.

关键词： super absorbent resin swelling kinetics water absorption graft copolymerization hydroxypropyl methyl cellulose

A Sustainable Strategy for Spent Cathode Carbon Blocks Hazardous Waste Recycling Using Binary Molten Salt Thermal Treatment

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Journal of Thermal science 2024年第3期33卷 1082-1093页

作者： LI Bin DING Yan JIAO Yuyong XU Fang WANG Xinyang ZHENG Fei ZOU Junpeng GAO Qiang HU Hongyun Faculty of Engineering China University of GeosciencesWuhan430074China institute for Natural disaster Risk prevention and Emergency Management China University of GeosciencesWuhan430074China State Key Laboratory of Coal Combustion Huazhong University of Science and TechnologyWuhan430074China

Waste-to-Energy treatment is a promising path to environment and energy management in the future.This work detailed a binary molten salt thermal treatment methodology for the detoxification of spent cathode carbon block(SCCB)waste and the recycling of carbonaceous materials.The thermal behavior of SCCB and SCCB blended with molten salts was investigated.It was found that the NaCl-Na_(2)CO_(3)binary molten salts significantly contributed to reducing pyrolysis onset temperature by 334.3 K compared to that of SCCB itself(i.e.,activation energy of pyrolysis reaction was reduced from 4.24×10^(5)to 2.30×10^(5)J/mol),thus helping to lower thermal treatment energy consumption.With the addition of binary molten salts,the residue after thermal treatment in a horizontal tube furnace experiment was separated into two layers.The bottom-layer residue was mainly composed of molten salts.The fluorine content in the form of NaF and CaF_(2)of top-layer residue was reduced significantly while the carbon content remained unchanged.Specifically,the leaching concentration of fluoride ion was decreased from 4620 mg/L to 856 mg/L.It is noted that the NaF and CaF_(2)can be removed through water-leaching and hydrothermal acid-leaching methods and thus the carbonaceous materials with a calorific value of 17.5 MJ/kg were obtained.

关键词： spent cathode carbon block hazardous solid waste detoxification binary-molten-salt thermal treatment carbon recycling pyrolysis kinetics

Energy mechanism of bolt supporting effect to fissured rock under static and dynamic loads in deep coal mines

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International Journal of Mining science and technology 2024年第3期34卷 371-384页

作者： Deyuan Fan Xuesheng Liu Yunliang Tan Xuebin Li Shenglong Yang College of Energy and Mining Engineering Shandong University of Science and TechnologyQingdao 266590China State Key Laboratory of Mining disaster prevention and Control Shandong University of Science and TechnologyQingdao 266590China National Energy Group Ningxia Coal Industry Co. Ltd.Yinchuan 753001China

The stability control of fissured rock is difficult,especially under static and dynamic loads in deep coal mines.In this paper,the dynamic mechanical properties,strain rate evolution and energy dissipation of fissured and anchored rocks were respectively obtained by SHPB tests.It was found that bolt can provide supporting efficiency-improving effect for fissured rock against dynamic disturbance,and this effect increased quadratically with decrease in anchoring angles.Then,the energy dissipation mechanism of anchored rock was obtained by slipping model.Furthermore,bolt energy-absorbing mechanism by instantaneous tensile-shear deformation was expressed based on material mechanics,which was the larger the anchoring angle,the smaller the energy absorption,and the less the contribution to supporting efficiency improvement.On this basis,the functional relationship between energy dissipation of anchored rock and energy absorption of bolt was established.Taking the coal-gangue separation system of Longgu coal mine as an example,the optimal anchoring angle can be determined as 57.5°–67.5°.Field monitoring showed fissured rock with the optimal anchoring angle,can not only effectively control the deformation,but also fully exert the energy-absorbing and efficiency-improving effect of bolt itself.This study provides guidance to the stability control and supporting design for deep engineering under the same or similar conditions.

关键词： Static and dynamic loads Anchored rock Energy absorption Anchoring angle Engineering verification

Deep Guided Attention Network for Joint Denoising and Demosaicing in Real Image

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Chinese Journal of Electronics 2024年第1期33卷 303-312页

作者： Tao ZHANG Ying FU Jun ZHANG School of Computer science and technology Beijing Institute of Technology Advanced Reasearch institute of Multidisciplinary science Beijing Institute of Technology

Denoising(DN) and demosaicing(DM) are the first crucial stages in the image signal processing pipeline. Recently, researches pay more attention to solve DN and DM in a joint manner, which is an extremely undetermined inverse problem. Existing deep learning methods learn the desired prior on synthetic dataset, which limits the generalization of learned network to the real world data. Moreover, existing methods mainly focus on the raw data property of high green information sampling rate for DM, but occasionally exploit the high intensity and signalto-noise(SNR) of green channel. In this work, a deep guided attention network(DGAN) is presented for real image joint DN and DM(JDD), which considers both high SNR and high sampling rate of green information for DN and DM, respectively. To ease the training and fully exploit the data property of green channel, we first train DN and DM sub-networks sequentially and then learn them jointly, which can alleviate the error accumulation. Besides, in order to support the real image JDD, we collect paired raw clean RGB and noisy mosaic images to conduct a realistic dataset. The experimental results on real JDD dataset show the presented approach performs better than the state-of-the-art methods, in terms of both quantitative metrics and qualitative visualization.

关键词： Image denoising Image demosaicing Joint processing Guided attention Paired real dataset

FRAGILITY ANALYSIS OF STRUCTURES WITH TUNED VISCOUS MASS DAMPERS UNDER NEAR-FAULT PULSE-TYPE GROUND MOTIONS

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Layered metastructure containing freely-designed local resonators for wave attenuation

Gongcheng Lixue/Engineering Mechanics 2024年第6期41卷 212-223页

作者： Zhang, Li-Li Han, Jian-Ping Li, Da-Wei Ma, Lian-Sheng Key Laboratory of disaster prevention and Mitigation in Civil Engineering of Gansu Province Lanzhou University of Technology Lanzhou 730050 China Western Engineering Research Center of disaster Mitigation in Civil Engineering of Ministry of Education Lanzhou University of Technology Lanzhou 730050 China School of science Lanzhou University of Technology Lanzhou 730050 China

A series of incremental dynamic analysis (IDA) were conducted on 6-storey 3-bay steel frames subjected to selected near-fault pulse-type ground motions. The frames are installed with tuned viscous mass dampers (TVMDs), viscous dampers (VDs) or no dampers, respectively. The seismic fragility curves corresponding to different damage states were obtained based on IDA results. The comparison of the seismic fragility of structures between TVMDs and VDs shows that the reliabilities of the main structure against different damage states are improved significantly with the addition of inerter element. Given the same damping ratio, the structure with TVMDs exhibits excellent improvement in seismic resistant capacity and low damage failure probability of the main structure against different damage states. With the increase of mass ratio, the improvement in structural performance due to TVMD does not decrease with the increase of nonlinearity. And the seismic mitigation effect of the structure is stable during the whole process including elasticity, elastic-plasticity and collapse. Furthermore, three sets of near-fault ground motion records with different pulse periods were selected for time history analysis, and the seismic mitigation effect of TVMD under near-fault pulse-type ground motions was discussed. The results show that under the near-fault pulse-type ground motions, TVMD does not always achieve the damping enhancement of the damping element, and the performance of the damper is related to the characteristics of ground motions. Compared with the enhanced structure with VDs and the original benchmark model, TVMD system reduces the input energy of the main structure when T1/Tp≥2. However, it has lower capacity of energy dissipation and the effect of damping enhancement could not be realized. When T1/Tp © 2024 Tsinghua University. All rights reserved.

关键词： Energy dissipation

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Defence technology（防务技术） 2024年第2期32卷 23-31页

作者： Yu Li Huguang He Jiang Feng Hailong Chen Fengnian Jin Hualin Fan State Key Laboratory for disaster prevention&Mitigation of Explosion&Impact Army Engineering University of PLANanjing 210007China Rocket Force University of Engineering Xi'an 710025China Henan International Joint Laboratory of Dynamics of Impact and disaster of Engineering Structures Department of Civil EngineeringNanyang Institute of TechnologyNanyang 473004China Guangxi Key Laboratory of disaster prevention and Engineering Safety and Key Laboratory of Disaster Prevention and Structural Safety of Ministry of EducationCollege of Civil Engineering and ArchitectureGuangxi UniversityNanning 530004China Research Center of Lightweight Structures and Intelligent Manufacturing State Key Laboratory of Mechanics and Control of Mechanical StructuresNanjing University of Aeronautics and AstronauticsNanjing 210016China

Combining periodic layered structure with three-dimensional cylindrical local resonators,a hybrid metastructure with improved wave isolation ability was designed and investigated through theoretical and numerical approaches.The metastructure is composed of periodic rubber layers and concrete layers embedded with three-dimensional resonators,which can be freely designed with multi local resonant frequencies to attenuate vibrations at required frequencies and widen the attenuation bandgap.The metastructure can also effectively attenuate seismic responses.Compared with layered rubber-based structures,the metastructure has more excellent wave attenuation effects with greater attenuation and wider bandgap.

关键词： Layered metastructure Local resonator Wave attenuation

Petrogenesis and Tectonic Implications of the Early Triassic Nianzi Adakitic Granite Unit in the Yanshan Fold and Thrust Belt:New Constraints from U-Pb Geochronology and Sr-Nd-Hf Isotopes

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Acta Geologica Sinica(English Edition) 2024年第1期98卷 50-66页

作者： ZHANG Huijun WU Chu HE Fubing WANG Biren CUI Yubin LIU Zhenghua YOU Shina DONG Jing Development and Research Center of the China Geological Survey Beijing 100037China Beijing institute of the Geological Survey Beijing 100095China institute of disaster prevention LangfangHebei 065201China

The Nianzi granite unit,which includes the Nianzi,Xiaolianghou and Xiawopu granitic intrusions,is a significant component of the northern part of the North China Craton(NCC)and is situated in the Yanshan fold and thrust belt(YFTB).However,there is still debate regarding the tectonic evolutionary history of the YFTB during the late Permian to Triassic period,specifically regarding the timing of subduction and collision between the NCC and the Paleo-Asian Ocean.The Nianzi granite unit exhibits unique petrological,geochronological and geochemical signatures that shed light on the tectonic evolutionary history of the YFTB.This study presents detailed petrology,whole-rock geochemistry,together with Sr-Nd isotopic,zircon U-Pb dating and Lu-Hf isotopic data of the granites within the Nianzi granite unit.Our findings demonstrate that the granites primarily consist of subhedral K-feldspar,plagioclase,quartz,minor biotite and hornblende,with accessory titanite,apatite,magnetite and zircon.Zircon U-Pb dating indicates that the Xiaolianghou granite was emplaced at 247.5±0.62 Ma.Additionally,the adakitic characteristics of the Nianzi,Xiawopu and Xiaolianghou granitic intrusions,such as high Sr and Ba contents and high ratios of Sr/Y and(La/Yb)N,combined with negative Sr-Nd and Lu-Hf isotopes(87Sr/86Sr)i=0.705681–0.7057433,εNd(t)=−21.98 to−20.97,zirconεHf(t)=−20.26 to−9.92,as well as the I-type granite features of high SiO_(2),Na_(2)O and K_(2)O/Na_(2)O ratios,enriched Rb,K,Sr and Ba,along with depleted Th,U,Nb,Ta,P and Ti,suggest that the Nianzi granitic unit was mainly derived from the partial melting of a thickened lower crust containing hydrous,calc-alkaline to high-K calc-alkaline,mafic to intermediate metamorphic rocks.In light of these parameters,we further integrate our data with previous studies and conclude that the Nianzi granitic unit was generated in a post-collisional extensional environment during the Early Triassic.

关键词： tectonic evolution zircon geochronology Sr-Nd-Hf isotopes Nianzi granite unit Yanshan fold and thrust belt