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Validation of critical strain technique for assessing stability of coal mine intersections and its potential for development of roof control plans

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Journal of Rock Mechanics and Geotechnical Engineering 2018年第2期10卷 380-389页

作者： S.Sinha y.p.chugh Colorado School of Mines GoldenCOUSA Southern Illinois University CarbondaleIL 62901USA

Both room-and-pillar and longwall mining systems develop underground excavations whose stability must be ensured over their entire service life. Even though rock bolts have been extensively used as a support element in US coal mines for about 40 years, limited research has been conducted in quantifying its composite reinforcement effects. Recently, the authors suggested an approach to quantify the reinforcement effect of roof supports over a designated area based on critical failure strains in tension, compression and shear. This paper validates the critical strain technique(CST) using a case study and justifies the magnitude of selected critical strain by corroborating with the US roof fall statistics. Intersections are vulnerable to failure due to the larger exposed roof span and associated stress concentrations. Through numerical application of the CST to a case study, it was demonstrated that modifying the opening orientation and installing reinforcement at critical locations can help to improve the overall stability of intersections.

关键词： Roof support Critical strain approach Numerical modeling

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Analysis of the effects of weak floor strata onlongwall face stability using finite element modeling

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Journal of Coal Science & Engineering(China) 2001年第1期7卷 1-8页

作者：马金荣 DebasisDeb y.p.chugh DepartmentofMiningandMineralResourcesEngineeringSouthernIllinoisUniversityatCarbondale

Higher production, better safety standard, and potential for automation are some of the benefits of longwall mining. Today, longwall face advances at a faster rate exposing many diversified rock layers in a short period of time. It is now a serious challenge to cope with ground control problems such as roof falls, face and floor failure, and excessive shield loading as fast as possible to minimize production and monetary losses. In Illinois Coal Mines, the existence of weak floor strata blow the coal seam may pose additional problems related to floor heaving, shield base punching, and associated roof and face falls. In this study, the effects of weak floor on longwall ground control are analyzed using two dimensional finite element models. A two leg 635 6 ton (700 short ton) yielding capacity shield is included in the models to evaluate the effects of different thickness and material properties of the weak floor. The study indicates that the thickness and material properties of weak floor have significant effects on shield loading, the distribution and intensity of front abutment stress, failure zones in the surrounding strata, roof to floor convergence, and floor punching by the shield base.

关键词： long wall face weak floor finite element in analysis

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Management of coal processing wastes： studies on an alternate technology for control of sulfate and chloride discharge

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International Journal of Coal Science & Technology 2018年第1期5卷 54-63页

作者： paul T. Behum yoginder p. chugh Liliana Lefticariu Office of Surface Mining and Reclamation Enforcement Alton IL 62002 USA National Academy of Inventors Tampa FL 33612 USA Department of Mining and Mineral Engineering Southern Illinois University Carbondale Carbondale IL 62901 USA Department of Geology Southern Illinois University Carbondale Carbondale IL 62901 USA

Management of coal mining and coal processing wastes, particularly of high sulfur coals, can generate excessive amounts of sulfate （SO4^2-） and chloride （Cl^-） in mine drainage that are known to negatively impact quality of both surface and ground water. The U.S. Environmental protection Agency provides guidance to states on allowable SO4^2- and Cl^- discharges from mine sites. This research evaluates the hypothesis that co-disposal of CCpW and FCpW with appropriate compaction can result in improved geochemical and geotechnical environments that will minimize acid mine drainage formation and SO4^2- and Cl^- discharges. Addition of ground limestone （ag-lime） to the mix was also evaluated as a drying agent and for improvement in overall geochemistry by buffering higher pH values within the coal waste. These objectives were to develop and implement innovative concepts for engineered co-management of CCpW and FCpW at coal mining sites. The authors performed long-term field column leaching studies to analyze improvement in SO4^2- and Cl^- in water quality. Requirements for stricter standards in some states led to the need for development of potentially improved environmental practices. This paper presents the overall encouraging results of the field kinetic studies.

关键词： Kinetic testing Acid mine drainage Coal chemistry Interior Basin Refuse co-disposal

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Goldenhar Syndrome with Occipital Meningoencephalocele: A Rare Case

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Open Journal of Modern Neurosurgery 2019年第1期9卷 17-22页

作者： Mubashshir Ali Ashish chugh Deepak M. Ranade Department of Neurosurgery Dr. D. Y. Patil Medical College Pune India

A 7-year-old male patient reported in our neurosurgery OpD with chief complaints of swelling in occipital region. The swelling was gradually increasing in size as per history given by patient’s attendant. Antenatal and birth history was uneventful. Developmental milestones were normal. Ear examination showed left sided pre auricular tag. Hearing was normal. Eye examination showed right eye limbal dermoid. Limbs examination showed syndactyly of 5th finger. Cardiovascular, respiratory and oral examination was normal. His height and weight were within normal limit. Chest X-ray was normal. Skeletal survey did not show any vertebral deformities. The karyotype was normal. The MRI brain showed a defect of size 1.3 cm in the occipital region through which cerebellum was seen herniating. The mass was surrounded by hypodense collection with multiple thickened septae within suggestive of CSF collection with thickened meninges. patient underwent surgery and cystic portion was removed, with preservation of the occipital and cerebellar parenchyma and closure of defect was done. patient responded well that there were no post operative complications and child was discharged on the 10th postoperative day. Hence, based on clinical and radiographic findings, a diagnosis of Goldenhar syndrome was made.

关键词： Goldenhar Syndrome Limbic Nodule

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由磁共振成像评估的主动脉弓脉搏波传导速度是心血管事件的预测因子:多种族动脉粥样硬化研究

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中华高血压杂志 2017年第8期25卷 724-724页

作者：刘莉叶鹏 Ohyama y Ambale-Venkatesh B Noda C Kim Jy Tanami y Teixido-Tura G chugh AR Redheuil A Liu Cy Wu CO Hundley WG Bluemke DA Guallar E Lima JAC

通过磁共振成像评估的主动脉弓脉搏波传导速度（pulse wave velocity,pWV）对心血管病事件的预测价值尚未完全确定。为了评估多种族动脉粥样硬化研究（multi-ethnic study of atherosclerosis,MESA）受试者中主动脉弓pWV与心血管病的关... 详细信息

通过磁共振成像评估的主动脉弓脉搏波传导速度（pulse wave velocity,pWV）对心血管病事件的预测价值尚未完全确定。为了评估多种族动脉粥样硬化研究（multi-ethnic study of atherosclerosis,MESA）受试者中主动脉弓pWV与心血管病的关系,Ohyama等纳入3527例MESA受试者[基线时平均年龄为（62±10）岁,47%为男性],

关键词：脉搏波传导速度磁共振成像心血管病事件心血管事件预测价值 ethnic 四分位间距交互作用

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Decline in subarachnoid haemorrhage volumes associated with the first wave of the COVID- 19 pandemic

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Stroke & Vascular Neurology 2021年第4期6卷 542-552,I0026-I0032页

作者： Thanh N Nguyen Diogo C Haussen Muhammad M Qureshi Hiroshi yamagami Toshiyuki Fujinaka Ossama y Mansour Mohamad Abdalkader Michael Frankel Zhongming Qiu Allan Taylor pedro Lylyk Omer F Eker Laura Mechtouff Michel piotin Fabricio Oliveira Lima Francisco Mont'Alverne Wazim Izzath Nobuyuki Sakai Mahmoud Mohammaden Alhamza R Al-Bayati Leonardo Renieri Salvatore Mangiafico David Ozretic Vanessa Chalumeau Saima Ahmad Umair Rashid Syed Irteza Hussain Seby John Emma Griffin John Thornton Jose Antonio Fiorot Rodrigo Rivera Nadia Hammami Anna M Cervantes-Arslanian Hormuzdiyar H Dasenbrock Huynh Le Vu Viet Quy Nguyen Steven Hetts Romain Bourcier Romain Guile Melanie Walker Malveeka Sharma Don Frei pascal Jabbour Nabeel Herial Fawaz Al-Mufti Atilla Ozcan Ozdemir Ozlem Aykac Dheeraj Gandhi Chandril chugh Charles Matouk pascale Lavoie Randall Edgell Andre Beer-Furlan Michael Chen Monika Killer-Oberpfalzer Vitor Mendes pereira patrick Nicholson Vikram Huded Nobuyuki Ohara Daisuke Watanabe Dong Hun Shin pedro SC Magalhaes Raghid Kikano Santiago Ortega-Gutierrez Mudassir Farooqui Amal Abou-Hamden Tatsuo Amano Ryoo yamamoto Adrienne Weeks Elena A Cora Rotem Sivan-Hoffmann Roberto Crosa Markus Möhlenbruch Simon Nagel Hosam Al-Jehani Sunil A Sheth Victor S Lopez Rivera James E Siegler Achmad Fidaus Sani Ajit S puri Anna Luisa Kuhn Gianmarco Bernava paolo Machi Daniel G Abud Octavio M pontes-Neto Ajay K Wakhloo Barbara Voetsch Eytan Raz Shadi yaghi Brijesh p Mehta Naoto Kimura Mamoru Murakami Jin Soo Lee Ji Man Hong Robert Fahed Gregory Walker Eiji Hagashi Steve M Cordina Hong Gee Roh Ken Wong Juan F Arenillas Mario Martinez-Galdamez Jordi Blasco Alejandro Rodriguez Vasquez Luisa Fonseca M Luis Silva Teddy y Wu Simon John Alex Brehm Marios psychogios William J Mack Matthew Tenser Tatemi Todaka Miki Fujimura Roberta Novakovic Jun Deguchi yuri Sugiura Hiroshi Tokimura Rakesh Khatri Michael Kelly Lissa peeling yuichi Murayama Hugh Stephen Winters Johnny Wong Mohamed Teleb Jeremy payne Hiroki Fukuda Kosuke Miyake Junsuke Shimbo yusuke Sug Neurology RadiologyBoston Medical CenterBostonMassachusettsUSA Neurology Marcus Stroke&Neuroscience CenterGrady Memorial HospitalEmory University School of MedicineAtlantaGAUSA Radiology Radiation OncologyBoston University School of MedicineBostonMassachusettsUSA Neurology National Hospital Organization Osaka National HospitalOsakaJapan Neurosurgery National Hospital Organization Osaka National HospitalOsakaJapan Neurology Alexandria UniversityAlexandriaEgypt Radiology Boston Medical CenterBostonMassachusettsUSA Department of Neurology Xinqiao HospitalChongqingChina Neurosurgery University of Cape TownRondeboschWestern CapeSouth Africa Neurosurgery Interventional NeuroradiologyClinica La Sagrada FamiliaBuenos AiresArgentina Neuroradiologie Neurologie VasculaireHospices Civils de LyonLyonAuvergne-Rhône AlpesFrance Neurologie Vasculaire Hospices Civils de LyonLyonAuvergne-Rhône AlpesFrance Interventional Neuroradiology Fondation Ophtalmologique Adolphe de RothschildParisÎle-de FranceFrance Neurology Hospital Geral de FortalezaFortalezaBrazil Interventional Neuroradiology Hospital Geral de FortalezaFortalezaBrazil Neuroradiology Nottingham University Hospitals NHS TrustNottinghamUK Department of Neurosurgery Kobe City Medical Center General HospitalKobeHyogoJapan Interventional Neurovascular Unit University Hospital CareggiFirenzeToscanaItaly Neuroradiology University Hospital Centre ZagrebZagrebCroatia Interventional Neuroradiology Hopital BicetreLe Kremlin-BicetreFrance Stroke and Interventional Neuroradiology Lahore General HospitalLahorePakistan Neurological Institute Cleveland Clinic Abu DhabiAbu DhabiUAE Department of Radiology Beaumont HospitalDublinIreland Neurology Stroke UnitHospital-Estadual CentralVitoriaBrazil Neuroradiology Instituto de Neurocirugia Dr AsengoSantiagoChile Interventional Neuroradiology Institut National de NeurologieTunisTunisia Neurology Boston Medical CenterBostonMassachusettsUSA Neurosurgery Boston Medical Center

Background During the COVID-19 pandemic,decreased volumes of stroke admissions and mechanical thrombectomy were *** study’s objective was to examine whether subarachnoid haemorrhage(SAH)hospitalisations and ruptured aneurysm coiling interventions demonstrated similar *** We conducted a cross-sectional,retrospective,observational study across 6 continents,37 countries and 140 comprehensive stroke *** with the diagnosis of SAH,aneurysmal SAH,ruptured aneurysm coiling interventions and COVID-19 were identified by prospective aneurysm databases or by International Classification of Diseases,10th Revision,*** 3-month cumulative volume,monthly volumes for SAH hospitalisations and ruptured aneurysm coiling procedures were compared for the period before(1 year and immediately before)and during the pandemic,defined as 1 March-31 May *** prior 1-year control period(1 March-31 May 2019)was obtained to account for seasonal *** There was a significant decline in SAH hospitalisations,with 2044 admissions in the 3 months immediately before and 1585 admissions during the pandemic,representing a relative decline of 22.5%(95%CI−24.3%to−20.7%,pptured aneurysms declined with 1170-1035 procedures,respectively,representing an 11.5%(95%CI−13.5%to−9.8%,p=0.002)relative *** analysis was noted for aneurysmal SAH hospitalisation decline from 834 to 626 hospitalisations,a 24.9%relative decline(95%CI−28.0%to−22.1%,pptured aneurysm coiling was noted in low coiling volume hospitals of 41.1%(95%CI 32.3%to 50.6%,p=0.008)despite a decrease in SAH admissions in this *** There was a relative decrease in the volume of SAH hospitalisations,aneurysmal SAH hospitalisations and ruptured aneurysm embolisations during the COVID-19 *** findings in SAH are consistent with a decrease in other emergencies,such as stroke and myocardial infarction.

关键词： diagnosis representing subarachnoid

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