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Journal of Environmental Sciences 2024年第4期138卷 428-438页

作者： Jing Yang Yujie Ren Shuoyu Chen Jinsuo Lu school of Environmental and municipal engineering Xi’an University of Architecture and TechnologyXi’an 710055China

This study aimed to explore the chemical looping gasification(CLG)reaction characteristics of the metal-supported composite phosphogypsum(PG)oxygen carriers(OCs)and the thermodynamic mechanism.The FactSage 7.1 thermodynamic simulation was used to explore the oxygen release and H_(2)S removal mechanisms.The experimental results showed that the syngas yield of CLG with PG-CuFe_(2)O_(4)was more than that with PG-Fe_(2)O_(3)20/CuO40 or PG-Fe_(2)O_(3)30/CuO30 OC at 1023 K when the water vapor content was 0.3.Furthermore,the maximum syngas yield of the CO selectivity was 70.3% and of the CO_(2)selectivity was 23.8%.The H_(2)/CO value was 0.78,and the highest carbon conversion efficiency was 91.9% in PG-CuFe_(2)O_(4)at the gasification temperature of 1073 K.The metal-supported PG composite oxygen carrier was proved not only as an oxygen carrier to participate in the preparation of syngas but also as a catalyst to catalyze coal gasification reactions.Furthermore,both the experimental results and FactSage 7.1 thermodynamic analysis revealed that the trapping mechanism of H_(2)S by composite OCs was as follows:CuO first lost lattice oxygen as an oxygen carrier to generate Cu_(2)O,which,in turn,reacted with H_(2)S to generate Cu_(2)S.This study provided efficient guidance and reference for OC design in CLG.

关键词： Metal-supported composite phosphogypsum Reaction characteristics Thermodynamic mechanism Chemical looping gasification

Road sub-surface defect detection based on gprMax forward simulation-sample generation and Swin Transformer-YOLOX

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Frontiers of Structural and Civil engineering 2024年第3期18卷 334-349页

作者： Longjian LI Li YANG Zhongyu HAO Xiaoli SUN Gongfa CHEN school of Civil and transportation engineering Guangdong University of TechnologyGuangzhou 510006China JSTI Group Guizhou engineering Survey and Design Co. Ltd.Guangzhou 510800China Guangzhou municipal engineering Testing Co. Ltd.Guangzhou 510520China

Training samples for deep learning networks are typically obtained through various field experiments,which require significant manpower,resource and time consumption.However,it is possible to utilize simulated data to augment the training samples.In this paper,by comparing the actual experimental model with the simulated model generated by the gprMax[1]forward simulation method,the feasibility of obtaining simulated samples through gprMax simulation is validated.Subsequently,the samples generated by gprMax forward simulation are used for training the network to detect objects in existing real samples.At the same time,aiming at the detection and intelligent recognition of road sub-surface defects,the Swin-YOLOX algorithm is introduced,and the excellence of the detection network,which is improved by augmenting the simulated samples with real samples,is further verified.By comparing the prediction performance of the object detection models,it is observed that the model trained with mixed samples achieved a recall of 94.74%and a mean average precision(maP)of 97.71%,surpassing the model trained only on real samples by 12.95%and 15.64%,respectively.The feasibility and excellence of training the model with mixed samples are confirmed.The potential of using a fusion of simulated and existing real samples instead of repeatedly acquiring new real samples by field experiment is demonstrated by this study,thereby improving detection efficiency,saving resources,and providing a new approach to the problem of multiple interpretations in ground penetrating radar(GPR)data.

关键词： ground penetrating radar gprMax forward modeling sample generation Swin-YOLOX object detection

Dynamic simulation insights into friction weakening effect on rapid long-runout landslides:A case study of the Yigong landslide in the Tibetan Plateau,China

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China Geology 2024年第2期7卷 222-236页

作者： Zi-zheng Guo Xin-yong Zhou Da Huang Shi-jie Zhai Bi-xia Tian Guang-ming Li school of Civil and transportation engineering Hebei University of TechnologyTianjin 300401China school of Geological engineering and Geomatics Chang’an UniversityXi’an 710054China Tianjin municipal engineering Design&Research Institute(TMEDI) Tianjin 300392China

This study proposed a novel friction law dependent on velocity,displacement and normal stress for kinematic analysis of runout process of rapid landslides.The well-known Yigong landslide occurring in the Tibetan Plateau of China was employed as the case,and the derived dynamic friction formula was included into the numerical simulation based on Particle Flow Code.Results showed that the friction decreased quickly from 0.64(the peak)to 0.1(the stead value)during the 5s-period after the sliding initiation,which explained the behavior of rapid movement of the landslide.The monitored balls set at different sections of the mass showed similar variation characteritics regarding the velocity,namely evident increase at the initial phase of the movement,followed by a fluctuation phase and then a stopping one.The peak velocity was more than 100 m/s and most particles had low velocities at 300s after the landslide initiation.The spreading distance of the landslide was calculated at the two-dimension(profile)and three-dimension scale,respectively.Compared with the simulation result without considering friction weakening effect,our results indicated a max distance of about 10 km from the initial unstable position,which fit better with the actual situation.

关键词： Rapid long-runout landslide PFC Friction weakening Three-dimension Numerical simulation Tibetan Plateau Hydrogeology engineering Geological hazards survey engineering

Analytical model for predicting time-dependent lateral deformation of geosynthetics-reinforced soil walls with modular block facing

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Journal of Rock Mechanics and Geotechnical engineering 2024年第2期16卷 711-725页

作者： Luqiang Ding Chengzhi Xiao Feilong Cui school of Civil and transportation engineering Hebei University of TechnologyTianjin300401China

To date,few models are available in the literature to consider the creep behavior of geosynthetics when predicting the lateral deformation(d)of geosynthetics-reinforced soil(GRS)retaining walls.In this study,a general hyperbolic creep model was first introduced to describe the long-term deformation of geosynthetics,which is a function of elapsed time and two empirical parameters a and b.The conventional creep tests with three different tensile loads(Pr)were conducted on two uniaxial geogrids to determine their creep behavior,as well as the a-Pr and b-Pr relationships.The test results show that increasing Pr accelerates the development of creep deformation for both geogrids.Meanwhile,a and b respectively show exponential and negatively linear relationships with Pr,which were confirmed by abundant experimental data available in other studies.Based on the above creep model and relationships,an accurate and reliable analytical model was then proposed for predicting the time-dependent d of GRS walls with modular block facing,which was further validated using a relevant numerical investigation from the previous literature.Performance evaluation and comparison of the proposed model with six available prediction models were performed.Then a parametric study was carried out to evaluate the effects of wall height,vertical spacing of geogrids,unit weight and internal friction angle of backfills,and factor of safety against pullout on d at the end of construction and 5 years afterwards.The findings show that the creep effect not only promotes d but also raises the elevation of the maximum d along the wall height.Finally,the limitations and application prospects of the proposed model were discussed and analyzed.

关键词： Geosynthetics Creep behavior Geosynthetics-reinforced soil(GRS)walls Lateral deformation Analytical model

Effect of Nozzle Inclination Angle on Fuel-Air Mixing and Combustion in a Heavy Fuel Engine

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Fluid Dynamics & Materials Processing 2024年第2期20卷 365-382页

作者： Zhigang Wang Bin Zheng Peidong Zhao Baoli Wang Fanyan Meng Wenke Xu Jian Meng school of transportation and Vehicle engineering Shandong University of TechnologyZibo255049China

Heavy-fuel engines are widely used in UAVs(Unmanned Autonomous Vehicles)because of their reliability and high-power density.In this study,a combustion model for an in-cylinder direct injection engine has been imple-mented using the AVL FIRE software.The effects of the angle of nozzle inclination on fuel evaporation,mixture distribution,and combustion in the engine cylinder have been systematically studied at 5500 r/min and consider-ing full load cruise conditions.According to the results,as the angle of nozzle inclination increases,the maximum combustion explosion pressure in the cylinderﬁrst increases and then it decreases.When the angle of nozzle incli-nation is less than 45°,the quality of the mixture in the cylinder and the combustion performance can be improved by increasing the angle.When the angle of nozzle inclination is greater than 45°,however,the mixture unevenness increases slightly with the angle,leading to a deterioration of the combustion performances.When the angle of nozzle inclination is between 35°and 55°,the overall combustion performance of the engine is rela-tively good.When the angle of nozzle inclination is 45°,the combustion chamber’s geometry and the cylinder’s airﬂow are well matched with the fuel spray,and the mixture quality is the best.Compared with 25°,the peak heat release rate increases by 20%,and the maximum combustion burst pressure increases by 5.5%.

关键词： Aviation heavy fuel piston engine nozzle inclination angle combustion fuel-air mixing

How does trip frequency distort time value to impact congestion charging schemes?

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transportation Safety and Environment 2024年第1期6卷 22-39页

作者： Maosheng Li Hangcong Li school of Traffic and transportation engineering Central South UniversityChangshaHunan 410075China

A notable feature of a city or region with close economic and social connections with its neighbours is its highly mixed local and external traffic,and in some cases the external traffic volume is almost as high as that of local traffic.Whilst local traffic volume may be largely made up of the same regular local commuters making frequent trips,external traffic from outside of the city(region)may not be the same people making regular trips to/from the city.However,from a large pool of people making infrequent trips to/from the city,the existence of external traffic is proven by data from the licence plate recognition system of road vehicles in Changde,China.The function of value of time correlated with the income/wage rate and trip frequency is exploited and verified statistically.The time value distorted by trip frequency is defined as perceived time value(PTV),which also influences the way travellers perceive any travel impedance such as congestion delay and toll charges.This paper analyses the price of anarchy(POA)when explicitly considering the travel frequency of the trip-makers and their PTV,and compares with previous analysis without considering travel frequency.We show that when travel frequency is considered,the optimal toll of congested road pricing schemes which converts road traffic flow from user equilibrium into system optimization is much lower than that without considering travel frequency.The cost of licence plate auction cannot be treated as a congestion toll,which is only a threshold of vehicle ownership.That travellers choose routes by PTV rather than TV(time value)is proven by an example of Heishipu Bridge in Changsha,Hunan Province,China.

关键词： road congestion charging travel frequency perceived time value road traffic impedance price of anarchy

Interface failure of segmental tunnel lining strengthened with steel plates based on fracture mechanics

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Frontiers of Structural and Civil engineering 2024年第1期18卷 137-149页

作者： Yazhen SUN Yang YU Jinchang WANG Longyan WANG school of transportation and Geomatics engineering Shenyang Jianzhu UniversityShenyang 110168China school of Civil engineering Shenyang Jianzhu UniversityShenyang 110168China Institute of transportation engineering Zhejiang UniversityHangzhou 310058China Center for Balance Architecture Zhejiang UniversityHangzhou310058China

Segmental tunnel lining strengthened with steel plates is widely used worldwide to provide a permanent strengthening method.Most existing studies assume an ideal steel-concrete interface,ignoring discontinuous deformation characteristics,making it difficult to accurately analyze the strengthened structure’s failure mechanism.In this study,interfacial fracture mechanics of composite material was applied to the segmental tunnel lining strengthened with steel plates,and a numerical three-dimensional solid nonlinear model of the lining structure was established,combining the extended finite element method with a cohesive-zone model to account for the discontinuous deformation characteristics of the interface.The results accurately describe the crack propagation process,and are verified by full-scale testing.Next,dynamic simulations based on the calibrated model were conducted to analyze the sliding failure and cracking of the steel-concrete interface.Lastly,detailed location of the interface bonding failure are further verified by model test.The results show that,the cracking failure and bond failure of the interface are the decisive factors determining the instability and failure of the strengthened structure.The proposed numerical analysis is a major step forward in revealing the interface failure mechanism of strengthened composite material structures.

关键词： segmental tunnel lining steel plate strengthening connecting interface cohesive-zone model extended finite element method

Resistance-capacitance model of the capillary heat exchanger in subway tunnels

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Energy and Built Environment

Energy and Built Environment 2024年第1期5卷 1-8页

作者： Zhen Tong Hao Wu Yiming Guan Yongming Ji Songtao Hu school of Environmental and municipal engineering Qingdao University of TechnologyQingdao 266033China

The subway operation generates a large amount of waste heat,which will lead to a disruption of the underground thermal balance.To remove the heat,a ground source heat pump system adopting capillary net as the front-end heat exchanger can be built in the tunnels to recycle the waste heat and use it for building heating.Different simulation method was used to analyze the heat transfer process in the tunnel and the surrounding rock.The existing simulation method usually takes a long time for calculation and can not be used for a real-time regulation of the system.Based on the concept of thermoelectric analogy,a resistance-capacitance(RC)model was proposed for rapid prediction and analysis on the heat transfer of the capillary net in subway tunnel.The annual thermal response in the tunnel was analyzed,and the influence of the tunnel air temperature and the capillary inlet water temperature was examined using this model.The maximum heat transfer flux of the capillary in summer(release heat)and in winter(extract heat)was 55.27 W/m 2 and 38.33 W/m 2,respectively.The effect of capillary inlet water temperature was more remarkable than that of the tunnel air temperature on the capillary heat exchange process.

关键词： Subway tunnel Heat pump Capillary heat exchanger Resistance-capacitance model

The optimization research on the coupled of active and passive energy supplying in public institutions in China

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Energy and Built Environment

Energy and Built Environment 2024年第2期5卷 288-299页

作者： Shui Yu Xueyan Liu Jianghui Yang Fuhong Han Jiashuai Wei school of municipal and Environmental engineering Shenyang Jianzhu UniversityShenyang 110168China

The building sector is one of the largest energy user and carbon emitters globally.To increase the utilization rate of renewable energy and reduce carbon dioxide emissions,the optimal technical scheme of active public institutions and coupled utilization of renewable energy is studied.In this study,the energy consumption of three types of public institutions in various regions of China was simulated by using DeST building energy consumption software,combined with energy conversion efficiency and data released by the National Bureau of Statistics,and the total energy demand and total energy supply of public institutions were predicted using the load density method.Based on the coupling mechanism of the MARKAL model,the optimal proportion of renewable energy in the energy supply of public buildings in different regions is determined.Through the study of the number of public institutions in various regions of China,energy consumption characteristics,construction area,and other related data,the reverse energy flow method is creatively proposed,and the active and renewable energy coupling algorithm from the energy demand side of public institutions to the energy supply side is established.The results show that the central region has the highest utilization rate of renewable energy in the public sector,reaching 36.18%.The use of renewable energy in public buildings in hot summer and warm winter zones decreased to 35.08%,and it was 12.82% in cold zones.By 2025,the proportion of renewable energy resources in China is expected to reach 29.2%.The energy coupling model and algorithm constructed in this paper can provide a basis for the coupling macro configuration of renewable energy in public institutions in China.

关键词： Public institutions Energy demand Energy supply Active and renewable energy coupling ratio Energy conversion efficiency

Effects of operating conditions on iron(hydr)oxides evolution and ciprofloxacin degradation in potassium ferrate-ozone stepwise oxidation system

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Journal of Environmental Sciences 2024年第1期135卷 367-378页

作者： Xiaochen Li Yifan Wang Ning Wang Mei Li Maomao Bai Jingtao Xu Hongbo Wang school of municipal and Environmental engineering Shandong Jianzhu UniversityJinan 250101China Resources and Environment Innovation Institute Shandong Jianzhu UniversityJinan 250101China

In this study,a stepwise oxidation system of potassium ferrate(K_(2)FeO_(4))combined with ozone(O+3)was used to degrade ciprofloxacin(CIP).The effects of pH and pre-oxidation time of K_(2)FeO_(4) on the evolution of K_(2)FeO_(4) reduction products(iron(hydr)oxides)and CIP degradation were investigated.It was found that in addition to its own oxidation capacity,K_(2)FeO_(4) can also influence the treatment effect of CIP by changing the catalyst content.The presence of iron(hydr)oxides effectively enhanced the mineralization rate of CIP by catalyzing ozonation.The pH value can influence the content and types of the components with catalytic ozonation effect in iron(hydr)oxides.The K_(2)FeO_(4) pre-oxidation stage can produce more iron(hydr)oxides with catalytic components for subsequent ozonation,but the evolution of iron(hydr)oxides components was influenced by O_(3) treatment.It can also avoid the waste of oxidation capacity owing to the oxidation of iron(hydr)oxides by O_(3) and free radicals.The intermediate degradation products were identified by Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR-MS).Besides,the degradation pathways were proposed.Among the degradation products of CIP,the product with broken quinolone ring structure only appeared in the stepwise oxidation system.

关键词： Potassium ferrate reduction products Catalytic ozonation Ciprofloxacin Potassium ferrate pre-oxidation time