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Journal of Iron and Steel Research(International) 2022年第6期29卷 1026-1038页

作者： Zhuo-wei Tan Zhen-bo Wang Shu-yu Bai Da-lei Zhang Sheng-zhu Zhang Frank Cheng Shao-hua Xing You-hai Jin China University of Petroleum(East China) Qingdao 266580ShandongChina Xiangtan University Xiangtan 411105HunanChina School of Materials Science and Engineering China University of Petroleum(East China)Qingdao 266580ShandongChina China Academy of Safety Science and Technology Beijing 100012China University of Calgary CalgaryAB T2N 1N4Canada State Key for Marine Corrosion and Protection Luoyang Ship Material Research InstituteQingdao 266237ShandongChina

The corrosive environment in long-distance natural gas pipeline was simulated by the online high shear stress flow test platform.The interaction between flow fields and local corrosion in different local corrosion stages was studied by machining different depths rectangular defect Pit(RDP)on X80 pipe steel specimens.The electrochemical signals of each specimen under high shear stress flow were measured online using an integrated three-electrode and electrochemical system.Raman spectroscopy confirmed that the corrosion scale of X80 pipeline steel in CO_(2)-saturated National Association of Corrosion Engineers solution was composed of FeCO_(3).The scanning electron microscope images displayed variations in microstructure of the corrosion scale at different RDP depths and different areas.The flow field fluctuations induced by RDP were analyzed by computational fluid dynamics simulations and the development of local corrosion Pits was discussed in terms of integrity of corrosion scale,convective mass transfer,and diffusion mass transfer.

关键词： CO_(2) corrosion Flow condition Rectangular defect Pit Local corrosion Corrosion electrochemistry

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基于Pit的皮肤镜图像分类方法研究

光电子．激光 2022年第5期33卷 505-512页

作者：韦春苗徐岩蒋新辉魏一铭兰州交通大学电子与信息工程学院柳州铁道职业技术学院人工智能学院

随着计算机技术的进步,现有的Transformer被扩展成处理计算机视觉任务的网络结构。为提高黑色素瘤的早期确诊率以提高皮肤病患者的治愈率,本文提出一种改进的基于Pit(pyramid pooling transformer)的网络模型来实现对7种皮肤病变的皮肤... 详细信息

随着计算机技术的进步,现有的Transformer被扩展成处理计算机视觉任务的网络结构。为提高黑色素瘤的早期确诊率以提高皮肤病患者的治愈率,本文提出一种改进的基于Pit(pyramid pooling transformer)的网络模型来实现对7种皮肤病变的皮肤镜图像进行自动分类。本文模型主要由Pit模块和抗干扰模块等2个部分组成,Pit继承了ViT的优点,并通过池化进行空间尺寸转换来提高模型的鲁棒性,经过预训练的Pit网络拥有大量的自然图像特征,且Pit部分网络可为下游的分类任务提供所需的图像特征,本文设计出抗干扰模块,用来抵抗皮肤镜图像中的干扰因素(如毛发、异物遮挡)的影响,从而提高模型性能、提高分类精度。实验结果表明,本文模型在ISIC 2018验证集上的分类准确率、精确率、召回率、F1-score值分别高达91.58%、83.59%、89.92%、86.34%,每秒传输帧数(frames per second,FPS)达到85 Hz与现有的几种先进的分类网络相比,分类性能和模型效率都有所提高,具有相对优势,证明本文模型具有一定的实用价值。

关键词：图像处理图像分类 Pit 抗干扰模块

A comparison of strategic mine planning approaches for in-Pit crushing and conveying, and truck/shovel systems

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International Journal of Mining Science and Technology 2018年第2期28卷 205-214页

作者： M.Nehring P.F.Knights M.S.Kizil E.Hay School of Mechanical and Mining Engineering The University of Queensland

In a global environment where energy and labor are becoming increasingly expensive, continuous mining systems such as In-Pit Crushing and Conveying(IPCC) systems have been advanced as offering a real alternative to conventional truck haulage systems. The implementation of IPCC systems in hard rock operations in open Pit mines however requires different and more comprehensive planning approaches in order to adequately reflect the practical aspects associated with these. This paper investigates the impact that these approaches may have on the implementation of IPCC systems on a basic metalliferous deposit amenable to open Pit exploitation. A strategic life of mine plan to provide numerous economic indicators for each approach is analyzed and compared to traditional truck haulage systems. The mine planning and evaluation process highlights the increased overall resource recovery that may accompany the use of IPCC systems. This investigation also provides insights into the issues associated with IPCC and the scale and type of operation and orebody that is likely to provide a feasible alternative to truck haulage.

关键词： In Pit crusher conveyor systems Strategic mine planning Resource recovery Surface metalliferous mining Mine optimization Truck and shovel

A study of fire propagation in coal seam with numerical simulation of heat transfer and chemical reaction rate in mining field

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International Journal of Mining Science and Technology 2019年第6期29卷 873-879页

作者： Moisés Oswaldo Bustamante Rúa Alan José Daza Aragón Pablo Bustamante Baena National University of Colombia Cr 65 # 63 20 CIMEX Minerals Institute

Spontaneous combustion of coal is a problem that affects the mining operation and generates environ-mental,economic,social and geotechnical impacts.This phenomenon has been divided into two pro-cesses:ignition and propagation.Fire propagation develops in coal seams because of a set of factors such as direction and wind speed,fracturing and temperature.In this work,heat transfer and chemical kinetics are studied from conservation equations of energy and species,respectively,using the software COMSOL Multiphysics to simulate the propagation of fires in coal seams.Two possible scenarios were analyzed that usually occur in the walls of the coal seams,such as fire focus and fire complete screens.It was found that the propagation kinetics of the fire changes depending on the temperature,the fractur-ing of rock mass and the area of fire influence.For temperature values lower than 300℃,there is con-sumption around 250 cm^3/h,values around 700℃,the consumption is 1500 cm^3/h,and for fires of 1200℃ have values of 3000 cm^3/h.Depending on the speed of propagation can vary from 4 to 17cm/day,considering on the level and fracturing of the final wall of the open Pit.

关键词： Spontaneous combustion of coal Open Pit mines Simulation Heat transfer Chemical reaction COMSOL

Statistical analysis to establish an ignition scenario based on extrinsic and intrinsic variables of coal seams that affect spontaneous combustion

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International Journal of Mining Science and Technology 2019年第5期29卷 731-737页

作者： M.O.Bustamante Rúa A.J.Daza Aragón P.Bustamante Baena J.D.Osorio Botero school mines national university of colombiamedellín 050036colombia

Spontaneous combustion of coal seams in open Pit mines is a problem that occurs in coal mines around the world.Theories have been developed that express several factors which generate self-heating in the coal and favor combustion.The synergy of these factors contributes to the increase in the temperature of oxidation reactions,facilitating the culmination of the activation energy of the system,in which the ignition develops and the reaction is spontaneous.Currently,the incidence of each variable’s susceptibility to coal combustion is unknown,so in this work a methodology was developed to determine statistically which of the variables has the greatest contribution in the phenomenon.Descriptive statistics,atypical values detection,principal component determination,cluster analysis,and logistic regression were used to determine how many indicator variables are necessary to describe susceptibility to coal combustion.For the analysis,21,000 data from different seams of two open-Pit coal mines in endwalls and abandoned Pits were processed with consideration given to extrinsic and intrinsic factors.Seam temperature,atmospheric pressure,wind speed,oxygen,methane,height,ash,volatile matter,heat power,vitrinite,liptinite and the Hardgrove Index are the most influential variables in the phenomenon.

关键词： Coal fire Self-ignition Statistics analysis Open Pit mines Spontaneous combustion

A Multi-scale Corrosion Fatigue Damage Model of Aluminum Alloy Considering Multiple Pits and Cracks

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Acta Mechanica Solida Sinica 2018年第6期31卷 731-743页

作者： Bin Sun Yang Zheng Zhaoxia Li Department of Engineering Mechanics Jiangsu Key Laboratory of Engineering MechanicsSoutheast UniversityNanjing 210000China Department of Information Center The Second Affiliated Hospital of Southeast UniversityNanjing 210000China

A multi-scale model is developed to link the continuum damage variable in macroscale to the number density of multiple Pits and cracks in microscale for studying the corrosion fatigue of aluminum alloy from multi-scale viewpoint.The developed model is used to predict the coherent multi-scale corrosion fatigue process of aluminum alloy component in the 3.5 wt% NaC1water solution under constant stress amplitude at a nominal frequency of 5Hz, and the numerical prediction results are compared with the experimental results.It shows that the model is effective and can be used to study the corrosion fatigue mechanisms of alurninum alloy from both macro and microscale viewpoints.

关键词： Multi-scale Continuum damage Pit Crack Corrosion fatigue Aluminum alloy

Overburden management in open Pits: options and limits in large limestone quarries

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International Journal of Mining Science and Technology 2019年第2期29卷 217-228页

作者： Claudio Oggeri Taddeo Maria Fenoglio Alberto Godio Raffaele Vinai Department of Environment Land and Infrastructure Engineering Politecnico di Torino College of Engineering Mathematics and Physical Sciences University of Exeter

The management of overburden is an important task in open Pit exploitations. Site topography and morphology as well as geological and geotechnical properties of natural and remoulded materials are the most important factors affecting the disposal phase. Economic and environmental requirements must be followed in order to achieve the best reclamation results, keeping into account site constraints such as slope stability, hauling and dumping issues, and interactions with groundwater. This paper deals with the above mentioned issues, illustrating a rational approach applied on the case of a large limestone quarry where the thickness of the overburden is relevant and the spoil material has to be dumped in a flooded Pit. The proposed multidisciplinary approach led to the selection of most suitable methods for excavation, transportation and disposal. The selection was based on a detailed laboratory and site characterisation that defined favorable and adverse factors to be considered during the preliminary study of a large quarrying project.

关键词： Open Pit Overburden Soil testing Limestone quarry Muck On-site testing

Numerical investigations of rock bridge effect on open Pit slope stability

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Journal of Rock Mechanics and Geotechnical Engineering 2019年第6期11卷 1184-1200页

作者： C.Romer M.Ferentinou Geological Sciences University of KwaZulu NatalDurbanSouth Africa civil engineering science university of johannesburgjohannesburgsouth africa

In this study,the effect of rock bridges on rock slope stability was investigated by incorporating nonpersistent joint networks in numerical models,and the critical profiles of an open Pit mine were analysed.Parallel deterministic networks of infinite and finite lengths,ubiquitous joint network model and Veneziano joint network model were used in order to simulate the rock fractures.Materials were modelled based on the generalised Hoek-Brown and equivalent Mohr-Coulomb failure criteria.The parallel deterministic infinite and the ubiquitous joint network models produced lower safety factors.The introduction of rock bridges along discontinuity planes in the parallel deterministic network and Veneziano joint network models significantly contributed to the stability and strain distribution,which should be considered in stability analysis of rock mass in open Pit by rock slope practitioners.The results show the significance of joints in hard rock behaviour and the joints should be included in order to attain practical and realistic simulations.

关键词： Ubiquitous model Veneziano model Parallel deterministic joint network Numerical modelling Rock slope stability Discontinuities Open Pit

A new framework for evaluation of rock fragmentation in open Pit mines

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Journal of Rock Mechanics and Geotechnical Engineering 2019年第2期11卷 325-336页

作者： Mohammad Babaeian Mohammad Ataei Farhang Sereshki Farzad Sotoudeh Sadjad Mohammadi Faculty of Mining Engineering Petroleum and GeophysicsShahrood University of Technology

The main purpose of blasting in open Pit mines is to produce the feed for crushing stage with the optimum dimensions from in situ rocks. The size distribution of muck pile indicates the efficiency of blasting pattern to reach the required optimum sizes. Nevertheless, there is no mature model to predict fragmentation distribution to date that can be used in various open Pit mines. Therefore, a new framework to evaluate and predict fragmentation distribution is presented based on the image analysis approach. For this purpose, the data collected from Jajarm bauxite mine in Iran were used as the sources in this study. The image analysis process was performed by Split-Desktop software to find out fragmentation distribution, uniformity index and average size of the fragmented rocks. Then, two different approaches including the multivariate regression method and the decision-making trial and evaluation laboratory(DEMATEL) technique were incorporated to develop new models of the uniformity index and the average size to improve the Rosin-Rammler function. The performances of the proposed models were evaluated in four blasting operation sites. The results obtained indicate that the regression model possesses a better performance in prediction of the uniformity index and the average size and subsequently the fragmentation distribution in comparison with DEMATEL and conventional Rosin-Rammler models.

关键词： Rock fragmentation Image analysis Open Pit mine Split-desktop software package Decision-making trial and evaluation laboratory(DEMATEL)technique

基于深度学习的皮肤镜图像自动分类与分割算法研究

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基于深度学习的皮肤镜图像自动分类与分割算法研究

作者：韦春苗兰州交通大学

学位级别：硕士

恶性黑色素瘤是一种致死率极高的的皮肤癌,因为黑色素瘤种类多样、病灶特征复杂,增加了其临床诊断的难度,早期的诊断和临床干预可大大减少患者的死亡率。而皮肤镜技术可以获取清晰放大的病灶特征信息,有利于帮助医生对病情进行分析诊断... 详细信息

恶性黑色素瘤是一种致死率极高的的皮肤癌,因为黑色素瘤种类多样、病灶特征复杂,增加了其临床诊断的难度,早期的诊断和临床干预可大大减少患者的死亡率。而皮肤镜技术可以获取清晰放大的病灶特征信息,有利于帮助医生对病情进行分析诊断。若仅靠医生对皮肤镜图像进行肉眼诊断,因具有丰富临床经验的医生数量较少,而且医生个人主观因素会影响诊断结果,会出现成本高、准确率低的问题。而如今,借助计算机技术对皮肤镜图像进行自动辅助诊断(主要包括皮肤镜图像分类与分割任务)是最高效、节约成本的解决方式,但因皮肤镜图像本身存在颜色不均、边界模糊、异物遮挡等问题,给皮肤镜图像自动分类与分割增加了难度。近年来,随着计算机技术的不断发展,利用深度学习对数据进行深度训练可有效获取图像深层特征,在医学图像分类与分割领域表现突出。因此本文在现有算法的基础上对皮肤镜图像进行系统分析和研究,提出了基于深度学习的皮肤镜图像自动分类与分割算法,论文的主要成果如下:1、提出一种改进的基于Pit(pyramid pooling transformer)的网络模型来实现对七种皮肤病变类型的皮肤镜图像进行自动分类。本文模型主要由Pit模块和抗干扰模块两个部分组成,Pit继承了Vi T的优点,并通过池化进行空间尺寸转换来提高模型的鲁棒性,经过预训练的Pit网络拥有大量的自然图像特征,且Pit部分网络可为下游的分类任务提供所需的图像特征,本文设计出抗干扰模块,用来抵抗皮肤镜图像中的干扰因素(如毛发、异物遮挡)的影响,从而提高模型性能、提高分类精度。实验结果表明,本文模型在ISIC 2018验证集上的分类准确率、precision、召回率、Fl-score值分别高达91.58%、83.59%、89.92%、86.34%,每秒传输帧数(FPS)达到85HZ与现有的几种先进的分类网络相比,分类性能和模型效率都有所提高,具有相对优势,证明本文模型具有一定的实用价值。2、提出一种皮肤镜图像自动分割算法。首先使用Resnet-34提取多种分辨率特征,在上下文部分使用Transformer模块对输入的特征进行全局建模;后通过混合池化模块聚合上下文特征的多尺度信息,在对应连接编解码器的跳跃连接间设计一个高效卷积模块来提高跳跃路径的边缘细化和抗干扰能力;最后利用解码器恢复图像分辨率并逐层融合其他浅层分辨率特征。在ISIC 2017、ISIC 2018公开数据集上进行实验,利用Focal loss函数改善难分割目标的精度,并与其他皮肤分割模型做实验对比,结果表明该算法的有效性。多组实验证明,本文所提出来的皮肤镜图像自动分类与分割算法获得更高的精度,对计算机临床辅助诊断研究具有一定的参考价值。

关键词： Pit Transformer 卷积神经网络深度学习图像处理