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Utilising the scientific method to demonstrate that slender beam/column behaviour is the dominant behavioural mechanism leading to roof/rib failure

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International Journal of Mining Science and Technology 2021年第5期31卷 867-887页

作者： mark colwell Russell Frith colwell Geotechnical Services CaloundraQLD 4551Australia Mine Advice Pty Ltd BeresfieldNSW 2322Australia

As per most other earth science engineering problems,the underground coal geotechnical environment and the way in which roof and rib support interacts with the rock mass are complex *** is therefore generally recognised that without prudent simplification,the complexity of the problem will overwhelm all current geotechnical methods of modelling,not least for the reason that a rock mass can never be characterised to a level that allows a"non-simplified"*** fact that numerical models,which are commonly purported to be a"simulation"tool and the so-called epitome of advanced geotechnical engineering,always need to be"calibrated"to a known reality is taken to be conclusive proof of this *** the problem should not be oversimplified(*** dominant failure mechanisms or critical data input parameters should not be ignored),without question judicious simplification is at the heart of all engineering design,to the point that it has a well-established name–"reductionism".The hypothesis addressed in this paper,is that horizontal and vertical stress-driven slender beam and column behaviour(which includes unstable Euler Buckling)are respectively the dominant(but not only)roadway roof and ribline behavioural mechanism that(if not controlled)can lead to excessive deformation,failure and eventual *** a part of the Scientific Method,a hypothesis can only be tested via real-world observations,measurements and analyses in establishing it is a credible *** the Scientific Method,this paper demonstrates that slender beam/column behaviour is the dominant instability mechanism within a coal mine roof/rib subject to elevated horizontal/vertical stress conditions and therefore,must be representatively accounted for in any credible empirical,analytical,or numerical approach to coal mine roof/rib stability assessment and associated ground support design.

关键词： Prudent simplification Behavioural mechanisms Support design Delamination Axial stress Buckling

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Modeling sustainability:population,inequality,consumption,and bidirectional coupling of the Earth and Human Systems

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National Science Review 2016年第4期3卷 470-494页

作者： Safa Motesharrei Jorge Rivas Eugenia Kalnay Ghassem R.Asrar Antonio J.Busalacchi Robert F.Cahalan mark A.Cane Rita R.colwell Kuishuang Feng Rachel S.Franklin Klaus Hubacek Fernando Miralles-Wilhelm Takemasa Miyoshi Matthias Ruth Roald Sagdeev Adel Shirmohammadi Jagadish Shukla Jelena Srebric Victor M.Yakovenko Ning Zeng University of Maryland College Park Institute for Global Environment and Society 3. Joint Global Change Research Institute College Park 4. University Corporation for Atmospheric Research 5. Johns Hopkins University Applied Physics Laboratory NASA Goddard Space Flight Center Lamont–Doherty Earth Observatory of Columbia University 8. Spatial Structures in the Social Sciences/Population Studies and Training Center Brown University RIKEN Advanced Institute for Computational Science School of Public Policy and Urban Affairs and Department of Civil and Environmental EngineeringNortheastern University 11. Department of AtmosphericOceanicand Earth SciencesGeorge Mason University

Over the last two centuries,the impact of the Human System has grown dramatically,becoming strongly dominant within the Earth System in many diferent ***,inequality,and population have increased extremely fast,especially since about 1950,threatening to overwhelm the many critical functions and ecosystems of the Earth *** in the Earth System,in turn,have important feedback efects on the Human System,with costly and potentially serious ***,current models do not incorporate these critical *** argue that in order to understand the dynamics of either system,Earth System Models must be coupled with Human System Models through bidirectional couplings representing the positive,negative,and delayed feedbacks that exist in the real *** particular,key Human System variables,such as demographics,inequality,economic growth,and migration,are not coupled with the Earth System but are instead driven by exogenous estimates,such as United Nations population *** makes current models likely to miss important feedbacks in the real Earth–Human system,especially those that may result in unexpected or counterintuitive outcomes,and thus requiring diferent policy interventions from current *** importance and imminence of sustainability challenges,the dominant role of the Human System in the Earth System,and the essential roles the Earth System plays for the Human System,all call for collaboration of natural scientists,social scientists,and engineers in multidisciplinary research and modeling to develop coupled Earth–Human system models for devising efective science-based policies and measures to beneit current and future generations.

关键词： Earth and Human System Models population migration inequality data assimilation bidirectional couplings and feedbacks sustainability

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全髋关节置换术后血栓预防使用便携式加压器或低分子量肝素的前瞻性随机对照研究

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中华骨科杂志 2010年第6期30卷 I0010-I0016页

作者： CliffordW. colwell Jr. mark I. Froimson Michael A.Mont Merrill A. Ritter Robert T. Trousdale Knute C. Buehler Andrew Spitzer Thomas K. Donaldson Douglas E. Padgett 勘武生(译) 不详武汉骨科医院 430033

背景：血栓栓塞性疾病是全髋关节置换术后常见的并发症。本研究的目的在于比较新型便携式加压器与低分子量肝素在静脉血栓预防中的安全性和有效性。方法：全髋置换患者随机接受为期10d便携式加压器或者低分子量肝素预防治疗。术中开始... 详细信息

背景：血栓栓塞性疾病是全髋关节置换术后常见的并发症。本研究的目的在于比较新型便携式加压器与低分子量肝素在静脉血栓预防中的安全性和有效性。方法：全髋置换患者随机接受为期10d便携式加压器或者低分子量肝素预防治疗。术中开始使用加压器，并且这组患者在术后日服81mg的阿司匹林。使用肝素者，术后12-24h开始注射低分子量肝素。在10-12d后，所有患者行多普勒超声筛查双下肢小腿、大腿部深静脉血栓；有肺栓塞临床症状的患者均接受肺部螺旋CT扫描评价。记录两组出血和于预性治疗情况（即：依从性）。术后12周进行深静脉血栓和肺栓塞证据的临床评估。结果：410例患者（414髋）进行随机化分组；392例患者（395髋）进行手术安全性评估，386例（389髋）治疗结果有效。两组间的一般临床情况无差异。加压组严重出血发生率O％，低分子量肝素组6％。加压组远端和近端深静脉血栓发生率分别为3％、2％，肝素组3％、1％。肺栓塞发生率加压组1％，肝素组1％，无致命性肺栓塞。随访12周，1例加压组患者出现两项事件（深静脉血栓和肺栓塞），该患者术后第12天多普勒超声检查阴性。在静脉血栓栓塞预防上两组比较无明显差异。结论：全髋置换术后静脉血栓栓塞预防，便携式加压器与低分子量肝素比较，可明显减少严重出血。

关键词：全髋关节置换术后前瞻性随机对照研究低分子量肝素血栓预防加压器便携式致命性肺栓塞多普勒超声检查

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