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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

How to avoid overtreatment of benign colorectal lesions:rationale for an evidence-based management

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World Journal of Gastroenterology 2022年第47期28卷 6619-6631页

作者： Marco bustamante-Balén Gastrointestinal Endoscopy Unit Gastrointestinal Endoscopy Research GroupHospital Universitari Ⅰ Politècnic La FeHealth Research Institute Hospital La Fe(ⅡSLaFe)Valencia 46026Spain

Implementing population-based screening programs for colorectal cancer has led to an increase in the detection of large but benign histological lesions.Currently,endoscopic mucosal resection can be considered the standard technique for the removal of benign lesions of the colon due to its excellent safety profile and good clinical results.However,several studies from different geographic areas agree that many benign colon lesions are still referred for surgery.Moreover,the referral rate to surgery is not decreasing over the years,despite the theoretical improvement of endoscopic resection techniques.This article will review the leading causes for benign colorectal lesions to be referred for surgery and the influence of the endoscopist experience on the referral rate.It will also describe how to categorize a polyp as complex for resection and consider an endoscopist as an expert in endoscopic resection.And finally,we will propose a framework for the accurate and evidence-based treatment of complex benign colorectal lesions.

关键词： Colorectal polyps Endoscopic mucosal resection Colorectal surgery

“倾听全球拍卖声音” 《时尚的未来:奢侈品再流通》

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中国拍卖 2022年第5期 15-19页

作者： Gab bustamante Mr.circulate二手奢侈品流通公司

市场概况奢侈品市场正在蓬勃发展根据美国二手电商平台Thred Up 2021年报告,过去的五年奢侈品交易额达到770亿美元。更多的卖家愿意放到网上卖,这驱动了二手奢侈品交易量激增。预计到2025年,二手奢侈品相比传统零售业的发展将要快11%左... 详细信息

市场概况奢侈品市场正在蓬勃发展根据美国二手电商平台Thred Up 2021年报告,过去的五年奢侈品交易额达到770亿美元。更多的卖家愿意放到网上卖,这驱动了二手奢侈品交易量激增。预计到2025年,二手奢侈品相比传统零售业的发展将要快11%左右。消费行为发生变化报告显示,仅2020年就有2.23亿消费者愿意接受二手奢侈品,这一消费行为变化也是二手奢侈品市场增长快速的原因。

关键词：传统零售业电商平台奢侈品消费行为市场概况卖家交易量交易额

父母苯暴露与儿童白血病危险性的系统综述与meta分析

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父母苯暴露与儿童白血病危险性的系统综述与meta分析

作者： Edgar Esteban bustamante Angel 东南大学

学位级别：硕士

背景:苯是作为一种挥发性有机化合物,广泛应用于生产和生活中,如干洗、油漆、印刷、橡胶和制鞋业等多个行业,有机溶剂接触是苯暴露的最重要来源之一,研究发现苯暴露与相关职业人群白血病的发生有密切关联。苯可在职业暴露的成年人中引... 详细信息

背景:苯是作为一种挥发性有机化合物,广泛应用于生产和生活中,如干洗、油漆、印刷、橡胶和制鞋业等多个行业,有机溶剂接触是苯暴露的最重要来源之一,研究发现苯暴露与相关职业人群白血病的发生有密切关联。苯可在职业暴露的成年人中引起急性骨髓细胞性白血病和其他血液癌,包括急性淋巴白血病,慢性淋巴白血病,多发性骨髓瘤和非霍奇金淋巴瘤。然而,苯的长期暴露是否可导致儿童患白血病风险增加的证据还有待进一步的阐明。目的:本研究首次通过meta分析研究父母苯(或有关溶剂)暴露接触与其子女患白血病的关联。方法:通过系统综述收集有关成人苯和有机溶剂暴露及其与儿童白血病进一步发生关系的文献。通过电子数据库搜索收集病例对照研究,然后按照PrISMA声明进行筛选。提取数据并收集以创建数据集;其研究随后使用纽卡斯尔-渥太华量表进行质量评估(NOS)进行评估。使用随机效应模型对暴露于苯或溶剂的两个人群(即父母)进行荟萃分析,以计算汇总的效应量ES(比值比)和数据集的95%CI。使用希金斯(Higgins)的I2测试,敏感性分析和亚组分析评估了母亲和父亲暴露组的变量暴露类型(苯或有机溶剂)和白血病类型(未分类的白血病,急性髓系白血病(AML),急性淋巴细胞白血病(ALL)和急性非淋巴细胞白血病(ANLL)的异质性。还使用Begg和Egger检验评估发表偏倚的存在。所有统计分析均使用STATA12软件进行,p值r的检验没有显示有显著的差异。结论:父母苯暴露可增加儿童患白血病的风险,其中母亲暴露的风险更高。父母苯暴露都与儿童AML发生的显著相关,母亲苯暴露与ALL发生显著相关。父母暴露于溶剂与儿童期白血病发生风险之间没有发现显著关联。进一步的研究需要确定父母苯暴露与儿童白血病的作用与机制。

关键词：儿童白血病急性淋巴细胞白血病(ALL) 急性髓系白血病(AML) 父母苯暴露职业苯暴露溶剂暴露挥发性有机化合物

Gone with the wind： Seasonal trends in foraging movement directions for a central-place forager

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Current Zoology 2014年第5期60卷 604-615页

作者： Jesus HErNANDEZ-PLIEGO Carlos rODrIGUEZ JavieR.bustamante Department of Wetland Ecology Estacion Biologica de Dofiana CSIC c/Amorico Vespucio s/n 41092 Seville Spain Department of Conservation Biology Estacion Biologica de Dofiana C SIC c/Amorico Vespucio s/n 41092 Seville Spain

Lesser kestrels Falco naumanni are migratory central-place foragers that breed in dynamic arable landscapes. After arriving from migration, kestrels have no knowledge of the distribution of crops, and consequently prey, around their colony. The energy demand of pairs increases as breeding season progresses, but at the same time prey abundance, and their knowledge on prey distribution, also increases. Wind can have a strong influence on flight cost and kestrels should try to reduce energy expendi- ture when possible. When prey abundance is low, kestrels have little knowledge of prey distribution, and pairs have no chicks, they could reduce foraging flight cost by leaving the colony with tailwinds. When prey is abundant, knowledge on prey distribu- tion has increased, and chick demand is high, kestrels should fly to the most favorable foraging patches. We analyzed foraging trips directions in a lesser kestrel colony along the breeding season and in relation to wind speed and direction. We recorded 664 foraging trips from 19 individuals using GPS-dataloggers. We found that outward flights direction changed from uniform to a concentrated distribution along the season, as prey abundance and individual experience increased. We also found a temporal trend in the angular difference between outward flights and wind directions, with low values early in the season and then increa- sing as expected, but again low values at the end, contrary to expectation. results suggest changes in kestrels foraging strategy along the season in relation to wind. Kestrels depart more with tailwinds in exploratory flights early in the season, while there is a spurious coincidence in direction to preferred foraging patches and dominant wind direction at the end [Current Zoology 60 (5):604-615, 2014].

关键词：季节性觅食运动方向飞行方向中央主导风向繁殖季节数据记录仪

Ketamine effect on intracellular and mitochondrial calcium mobilization

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BIOCELL 2016年第1期40卷 11-14页

作者： JUANITA bustamante ANALIA CZErNICZYNIEC SILVIA LOrES-ArNAIZ Centro de Altos Estudios en Ciencias Humanas y de la Salud(CAECIHS) Facultad de MedicinaUniversidad Abierta InteramericanaBuenos AiresArgentina Instituto de Bioquímica y Medicina Molecular Facultad de Farmacia y BioquímicaUniversidad de Buenos AiresArgentina

The suppressive effects of ketamine on intracellular calcium has been reported in a variety of cells although the mechanisms involved are not well understood.The aim of this work was to evaluate the ketamine effect on the mitochondrial Ca^(2+)accumulation and the cellular Ca^(2+)mobilization using FLUO4-AM and flow cytometry.The results showed that mitochondria from ketamine injected animals presented a lower ability to retain calcium at concentrations higher than 20μM,as compared with controls(saline injected animals).In ad-dition,ketamine showed a significant decreased KCl-induced intracellular calcium concentration.KCl increased calcium influx through cellular depolarization.According to the data presented herein,ketamine presents a clear inhibitory effect on cytosolic Ca2+transport mechanisms,independently from their action on the calcium channel associated NMDA receptor.

关键词： calcium transport hippocampal mitochondria Vero cell culture

Constructing Hopf Insulator from Geometric Perspective of Hopf Invariant

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Chinese Physics Letters 2024年第3期41卷 121-126页

作者：常治文郝维昌 Miguel bustamante 刘鑫 Institute of Theoretical Physics School of Physics and Optoelectronic EngineeringBeijing University of TechnologyBeijing 100124China School of Physics Beihang UniversityBeijing 100191China Complex and Adaptive Systems Laboratory School of Mathematics and StatisticsUniversity College DublinBelfield4DublinIreland

We propose a method to construct Hopf insulators based on the study of topological defects from the geometric perspective of Hopf invariant I.Firstly,we prove two types of topological defects naturally inhering in the... 详细信息

关键词： Hopf topological invariant

Effect of cerium/lanthanum addition on microstructure and mechanical properties of Al7075 alloy via mechanical alloying and sintering

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Journal of rare Earths 2016年第4期34卷 420-427页

作者： r.Pérez-bustamante A.reyna-Cruz D.C.Acosta-Pena C.r.Santillán-rodríguez J.A.Matutes-Aquino F.Pérez-bustamante M.C.Maldonado-Orozco J.Aguilar-Santillán r.Martínez-Sánchez research Center in Advanced Materials(CIMA V) National Laboratory of NanotechnologyMiguel de Cervantes No.120C.P.31109ChihuahuaChih.Mexico Faculty of Engineering Autonomous University of Chihuahua(UACH)Circuito No.1 Nuevo Campus UniversitarioC.P.31 125ChihuahuaChih.Mexico Faculty of Chemical Sciences Autonomous University of Chihuahua(UACH)Circuito No.1 Nuevo Campus UniversitarioC.P.31125ChihuahuaChih.Mexico Materials&Tools LLC 4118 E Washington CtGilbertAZUSA 85234

The effect of the Al-6Ce-3La（ACL） on the microstructural behavior of the Al7075 was investigated. Materials were synthesized by mechanical alloying with variation in the ACL content and milling time. Products were characterized and studied in the as-milled condition and mechanically evaluated after sintering. The synergetic effect of milling time and ACL content in the modified materials led to a reduction in the particle size. results from electron microscopy showed a homogeneous dispersion of Ce/La phases up to 20 wt.% of ACL content after 10 h of milling. Mechanical evaluation under compressive test showed an improved performance for those alloys reinforced with 0.2 wt.% and 0.5 wt.% of ACL.

关键词： mechanical alloying rare earths aluminum microstructure sintering