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Performance evaluation of near real-time condition monitoring in haul trucks

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International Journal of Mining Science and Technology 2020年第6期30卷 909-915页

作者： Hemanth Reddy Alla Robert Hall derek b.Apel University of Alberta Edmonton T6G 2H5Canada

Strategic maintenance plays a key role in ensuring high availability and utilization of the haul trucks,and as equipment began to grow more complex towards the end of the 20th century,there was a need for a proactive maintenance strategy,which led to the development of condition-based maintenance.Realtime condition monitoring(RTCM)is the ability to perform condition monitoring in real-time and has the ability to alert maintenance and operations of abnormal conditions.These alarms can be used as an indication leading to a problem,and if a suitable corrective action is initiated in time,it could result in significant savings of equipment downtime and repair costs.This study aims to compare some maintenance performance indicators prior to and after implementation of RTCM strategy at a mine site using some tests of statistical significance.The study also indicated the presence of seasonality in the data,and thus the data was deseasonalized and detrended prior to being subjected to the statistical tests.Finally,the results indicated that RTCM strategy has proven to be successful in improving the availability for some of the failure categories chosen in this study.

关键词： Haul trucks Real-time condition monitoring Performance indicators

Machine learning methods for rockburst prediction-state-of-the-art review

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International Journal of Mining Science and Technology 2019年第4期29卷 565-570页

作者： Yuanyuan Pu derek b.Apel Victor Liu Hani Mitri School of Mining and Petroleum Engineering University of AlbertaEdmonton T6G 2R3Canada Department of Mining and Materials Engineering McGill UniversityMontreal H3A 2T6Canada

One of the most serious mining disasters in underground mines is rockburst phenomena.They can lead to injuries and even fatalities as well as damage to underground openings and mining equipment.This has forced many researchers to investigate alternative methods to predict the potential for rockburst occurrence.However,due to the highly complex relation between geological,mechanical and geometric parameters of the mining environment,the traditional mechanics-based prediction methods do not always yield precise results.With the emergence of machine learning methods,a breakthrough in the prediction of rockburst occurrence has become possible in recent years.This paper presents a state-ofthe-art review of various applications of machine learning methods for the prediction of rockburst potential.First,existing rockburst prediction methods are introduced,and the limitations of such methods are highlighted.A brief overview of typical machine learning methods and their main features as predictive tools is then presented.The current applications of machine learning models in rockburst prediction are surveyed,with related mechanisms,technical details and performance analysis.

关键词： Rockburst prediction burst liability Artificial neural network Support vector machine Deep learning

Assessment of digital image correlation method in determining large scale cemented rockfill strains

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International Journal of Mining Science and Technology 2019年第5期29卷 771-776页

作者： bob A.Lingga derek b.Apel Mohammadali Sepehri Yuanyuan Pu School of Mining and Petroleum Engineering University of AlbertaEdmonton T6G 2W2Canada

A conventional contact method(using linear transducers)and a non-contact method are deployed to measure the axial and lateral deformations of large scale cylindrical cemented rockfill specimens.Experimental works incorporating two pinhole cameras to create one stereovision by digital image correlation shows that the non-contact method is as reliable for testing large cylindrical specimens as measurements done by using linear variable displacement transformer and string potentiometer.Considering this particular large specimen,the experiment resulted in the acceptable mean difference between lateral strain using both methods is 5.1 percent,and 14.5 percent for the axial strain.This occurrence is inevitable due to the heterogeneity of the concrete system and the placement of the monitoring point in digital image correlation method,although the comparison of stress-strain relationship in both methods still indicates a conformity.based on the results of the present experiments,the authors recommend the noncontact method for a detailed investigation of the material behavior during the uniaxial compressive strength tests.Full field strain measurement enables this digital method to examine local strains near cracks at any point,a very useful tool for studying material deformation behavior.

关键词： Experimental testing Cemented rockfill Digital image correlation Strain measurement Mine backfill

Improving modeling of low-altitude particulate matter emission and dispersion:A cotton gin case study

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Journal of Environmental Sciences 2023年第11期133卷 8-22页

作者： Zijiang Yang Michael N.Evans Michael D.buser Cathleen J.Hapeman Alba Torrents derek P.Whitelock Department of Civil and Environmental Engineering University of Maryland College Park1173 Glenn L.Martin HallCollege ParkMaryland 20742United States Department of Geology University of Maryland College Park1212B Chemistry BuildingCollege ParkMaryland 20742United States Earth System Science Interdisciplinary Center 1120 Geology BuildingUniversity of MarylandCollege ParkMaryland 20742United States United States Department of Agriculture Agricultural Research ServiceOffice of National Programs5601 Sunnyside Ave(GWCC 4–2282)BeltsvilleMaryland 20705United States United States Department of Agriculture Agricultural Research ServiceHenry A.Wallace Beltsville Agricultural Research Center10300 Baltimore AvenueBeltsvilleMaryland 20705United States United States Department of Agriculture Agricultural Research ServiceSouthwestern Cotton Ginning Research LaboratoryPO Box 578Mesilla ParkNew Mexico 88047United States

Monitoring and modeling of airborne particulate matter(PM)from low-altitude sources is becoming an important regulatory target as the adverse health consequences of PM become better understood.However,application of models not specifically designed for simulation of PM from low-altitude emissions may bias predictions.To address this problem,we describe the modification and validation of an air dispersion model for the simulation of lowaltitude PM dispersion from a typical cotton ginning facility.We found that the regulatory recommended model(AERMOD)overestimated pollutant concentrations by factors of 64.7,6.97 and 7.44 on average for PM 2.5,PM 10,and TSP,respectively.Pollutant concentrations were negatively correlated with height(pbased on these results,we developed dispersion correction factors for AERMOD and cross-validated the revised model against independent observations,reducing overestimation factors to 3.75,1.52 and 1.44 for PM 2.5,PM 10 and TSP,respectively.Further reductions in model error may be obtained from use of additional observations and refinement of dispersive correction factors.More generally,the correction permits the validated adjustment and application of pre-existing models for risk assessment and development of remediation techniques.The same approach may also be applied to improve simulations of other air pollutants and environmental conditions of concern.

关键词： Air quality Particulate matter Air dispersion modelling Cotton gin

Modes of multi-mechanistic gas diffusion in shale matrix at varied effective stresses:Observations and analysis

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Petroleum Science 2023年第5期20卷 2908-2920页

作者： Tian-Yu Chen Yan-Yu Hao derek Elsworth Hong-Ming Zhang Zhi-Ming Hu Guang-Lei Cui Key Laboratory of Ministry of Education on Safe Mining of Deep Metal Mines School of Resources and Civil Engineering and Key Laboratory of Liaoning Province on Deep Engineering and Intelligent TechnologyNortheastern UniversityShenyang110819LiaoningChina National Energy Shale Gas R&D(experiment)Center Langfang065007HebeiChina Department of Energy and Mineral Engineering EMS Energy Institute and G3 CenterPennsylvania State UniversityUniversity ParkPA16802USA Research Institute of Petroleum Exploration&Development PetroChina Company LimitedBeijing100084China

Gas diffusion in the shale matrix has a dominant effect on late-stage production from shale gas reservoirs.However,adequate research on the mechanisms and contributions of gas diffusion for varied pore size populations in shale matrix under recreated in situ stress is lacking.We report gas-diffusion measurements under constant in situ stress but variable gas pressures for contrasting non-adsorbent(helium(He))and adsorbed(methane(CH_(4)))gases to investigate the impact of effective stress on the evolution of dominant mechanisms of diffusion.An intact sample replicates true pore-network topology and diffusion paths.An integrated diffusion model is proposed that combines the effects of slip flow,Knudsen flow,and surface diffusion to constrain the evolution of these flow regimes and their respective contributions to the observational data.Finally,a probability density function(PDF)is employed to separate the gas content distributions of macropores and micropores from the total gas content and to investigate gas contributions in various pores.The results reveal that the diffusion coefficients of both He and CH_(4) in macropores and micropores increase with gas pressure but decrease with increasing effective stress.The diffusion coefficients of He and CH_(4) are different in macropores but remain nearly the same in micropores.The diffusion coefficients of slip flow and surface diffusion increase with decreasing effective stress except for CH_(4) diffusion in the micropores,while the evolution of Knudsen diffusion shows the opposite trend.Slip flow plays a dominant role in He and CH_(4) diffusion within macropores(pore size 45 nm).Knudsen diffusion gradually becomes significant for He diffusion in the micropores(pore size 4 nm),conversely,for CH_(4) diffusion in the micropores,surface diffusion becomes significant.Related to gas production from reservoirs,the contributions of the micropores will increase gradually with the duration of gas recovery,indicating the significant role of gas diffusion in micropores to steady

关键词： Diffusion coefficient In situ stress Varied pore types Diffusion mechanisms Gas-content contributions

吉木萨尔凹陷页岩油密切割压裂多簇裂缝竞争扩展模拟

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石油学报 2022年第1期43卷 75-90页

作者：侯冰常智武安安 Elsworth derek 中国石油大学(北京)油气资源与探测国家重点实验室北京102249 中国石油大学(北京)石油工程教育部重点实验室北京102249 中国石油长庆油田公司油气工艺研究院陕西西安710021 宾夕法尼亚州立大学美国宾夕法尼亚州16802

针对吉木萨尔凹陷芦草沟组页岩油储层地质特征,建立了重点改造井的密切割体积压裂裂缝扩展三维离散元数值模型,模型依据成像测井资料设置了随机分布的天然层理和高角度裂缝,依据纵向分层数据设置了小层及层间界面。模型模拟了不同分簇... 详细信息

针对吉木萨尔凹陷芦草沟组页岩油储层地质特征,建立了重点改造井的密切割体积压裂裂缝扩展三维离散元数值模型,模型依据成像测井资料设置了随机分布的天然层理和高角度裂缝,依据纵向分层数据设置了小层及层间界面。模型模拟了不同分簇数和簇间距下的复杂裂缝扩展过程,分析了密切割体积压裂改造过程中多簇裂缝竞争扩展规律和改造后裂缝系统的立体产状。通过数值模拟分析可知:(1)页岩油储层密切割压裂过程中,多条水力裂缝竞争扩展程度随分簇数的增加及簇间距的减小而增强;(2)裂缝的竞争扩展是一个地应力、裂缝形态、裂缝宽度动态平衡的过程;(3)在相同泵排量和压裂时长条件下多簇裂缝系统的波及范围与储层改造面积(SRA)负相关;(4)高角度天然裂缝更易阻滞和捕获横切缝(垂直于水平井眼的人工主裂缝);(5)多簇裂缝系统的包络面呈"礼帽"形状,采用交错布置邻井压裂段位置有利于缩减井间未动用储层中油气的渗流距离。

关键词：页岩油裂缝系统竞争扩展离散元储层改造面积吉木萨尔凹陷

Photoreduction adjusted surface oxygen vacancy of bi_(2)MoO_(6) for boosting photocatalytic redox performance

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Frontiers of Chemical Science and Engineering 2023年第12期17卷 1937-1948页

作者： Tie Shi Hailong Jia Yanmei Feng bo Gong Daimei Chen Yu Liang Hao Ding Kai Chen derek Hao beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes National Laboratory of Mineral MaterialsSchool of Materials Science and TechnologyChina University of GeosciencesBeijing 100083China School of Materials Science and Technology Shenyang University of Chemical TechnologyShenyang 110142China Collaborative Innovation Center of Atmospheric Environment and Equipment Technology Jiangsu Key Laboratory of Atmospheric Environment Monitoringand Pollution Control School of Environmental Science and EngineeringNanjing University of Information Science and TechnologyNanjing 210044China Centre for Technology in Water and Wastewater(CTWW) School of Civil and Environmental EngineeringUniversity of Technology Sydney(UTS)NSW 2007Australia

In this study, bi_(2)MoO_(6) with adjustable rich oxygen vacancies was prepared by a novel and simple solvothermal-photoreduction method which might be suitable for a large-scale production. The experiment results show that bi_(2)MoO_(6) with rich oxygen vacancies is an excellent photocatalyst. The photocatalytic ability of bMO-10 is 0.3 and 3.5 times higher than that of the pristine bi_(2)MoO_(6) for Rhodamine b degradation and Cr(VI) reduction, respectively. The results display that the band energy of the samples with oxygen vacancies was narrowed and the light absorption was broadened. Meanwhile, the efficiency of photogenerated electron-holes was increased and the separation and transfer speed of photogenerated carriers were improved. Therefore, this work provides a convenient and efficient method to prepare potential adjustable oxygen vacancy based photocatalysts to eliminate the pollution of dyes and Cr(VI) in water.

关键词： bi_(2)MoO_(6) oxygen vacancies photoreduction Cr(VI) Rhb

不同应力路径下含瓦斯煤的声发射特性与能量演化规律

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中南大学学报（自然科学版） 2023年第6期54卷 2323-2337页

作者：陈结张允瑞蒲源源杜俊生舒龙勇赵旭生张志刚 derek b.Apel 重庆大学资源与安全学院重庆400044 重庆大学煤矿灾害动力学与控制国家重点实验室重庆400044 煤炭科学技术研究院有限公司安全分院北京100013 煤炭科学研究总院煤炭资源高效开采与洁净利用国家重点实验室北京100013 中煤科工集团重庆研究院有限公司重庆400037 阿尔伯塔大学石油与矿业工程学院加拿大埃德蒙顿T6G 2R3

为了研究含瓦斯煤在不同扰动作用下的声发射特性和能量演化规律,利用多场煤与瓦斯突出过程宏细观试验系统,开展6种应力路径下的含瓦斯煤轴向加卸载试验,分析应力路径对含瓦斯煤声发射特性和变形特性的影响,并得到含瓦斯煤在循环加卸载... 详细信息

为了研究含瓦斯煤在不同扰动作用下的声发射特性和能量演化规律,利用多场煤与瓦斯突出过程宏细观试验系统,开展6种应力路径下的含瓦斯煤轴向加卸载试验,分析应力路径对含瓦斯煤声发射特性和变形特性的影响,并得到含瓦斯煤在循环加卸载过程中的能量演化特征及储能规律。研究结果表明:含瓦斯煤在吸附过程中的振铃计数随吸附时间增长而减少,根据出气口压力变化趋势将吸附过程分为3个阶段,分别为外扩散阶段、内扩散阶段和吸附饱和阶段;含瓦斯煤在加卸载过程中的振铃计数主要分布在应力上升区段,出现了明显的Kaiser效应,累计振铃计数在循环加卸载路径下呈“阶梯”形增长,且随着循环次数增加和应力路径延长而增大;含瓦斯煤在不同循环加卸载路径下的能量演化规律具有一致性,各能量密度均随着轴向应力增加而呈现二次函数型增长,并经历了减速增长、线性增长和加速增长的3个阶段;同时,弹性能密度和总输入能密度之间存在线性关系,储能系数为定值且均在50%以上。

关键词：应力路径加卸载含瓦斯煤声发射能量演化

Numerical modeling for rockbursts:A state-of-the-art review

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Journal of Rock Mechanics and Geotechnical Engineering 2021年第2期13卷 457-478页

作者： Jun Wang derek b.Apel Yuanyuan Pu Robert Hall Chong Wei Mohammadali Sepehri School of Mining and Petroleum Engineering University of AlbertaEdmontonAlbertaT6G 2R3Canada State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing UniversityChongqing400044China

As the depth of excavation increases,rockburst becomes one of the most serious geological hazards damaging equipment and facilities and even causing fatalities in mining and civil engineering.This has forced researchers worldwide to identify different methods to investigate rockburst-related problems.However,some problems,such as the mechanisms and the prediction of rockbursts,continue to be studied because rockburst is a very complicated phenomenon influenced by the uncertainty and complexity in geological conditions,in situ stresses,induced stresses,etc.Numerical modeling is a widely used method for investigating rockbursts.To date,great achievements have been made owing to the rapid development of information technology(IT)and computer equipment.Hence,it is necessary and meaningful to conduct a review of the current state of the studies for rockburst numerical modeling.In this paper,the categories and the origin of different numerical approaches employed in modeling rockbursts are reviewed and the current usage of various numerical modeling approaches is investigated by a literature research.Later,a state-of-the-art review is implemented to investigate the application of numerical modeling in the mechanism study,and prediction and prevention of rockbursts.The main achievements and problems are highlighted.Finally,this paper discusses the limitations and the future research of numerical modeling for rockbursts.An approach is proposed to provide researchers with a systematic and reasonable numerical modeling framework.

关键词： Rockburst Numerical modeling Rockburst mechanism Dynamic modeling