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Spreadability of powders for additive manufacturing: A critical review of metrics and characterisation methods

PARTICUOLOGY 2024年第10期93卷 211-234页

作者： Talebi, Fatemeh A. Haydari, Zobaideh Salehi, Hamid Mehrabi, Mozhdeh Gardy, Jabbar b.adley, mike bayly, Andrew E. Hassanpour, Ali Univ Leeds Sch Chem & Proc Engn Leeds LS2 9JT England Univ Greenwich Sch Engn Greenwich ME4 4TB England Cormica Ltd Listerhills Sci PkCampus Rd Bradford BD7 1HR England

Powder bed fusion methods of additive manufacturing (AM) require consistent, reproducible, and uniform layers of powder for the reliable production of high-quality parts, where properties of powder are central to achieving this. Among these properties, powder flowability and spreadability play critical roles in determining the quality of these powder layers. While extensive research has been conducted on powder flow and spreading behaviour, and on their characterisation, there is little critical comparison and review of these terms in the context of AM. Such a review is necessary to further develop and enhance our comprehension of spreading dynamics and its relation to powder properties in AM systems. This review paper aims to build a coherent understanding of the correlation between powder characteristics and spreading in powder based additive manufacturing and its impact on manufactured parts. It highlights the current progress in comprehending spreading dynamics, the influence of powder characteristics, environmental conditions, spreading system, and the development of testing tools to assess powder spreadability. Furthermore, the paper critically discusses the challenge of finding appropriate quantitative metrics and recent advances in the use of standardised methods for evaluating powder spreadability. (c) 2024 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier b.V. This is an open access article under the CC bY license (http:// ***/licenses/by/4.0/).

关键词： Powder spreading Powder flowability Powder properties Quality of layer and final products DISCRETE ELEMENT SIMULATION PARTICLE-SIZE DISTRIbUTION SPREADING PROCESS FLOW PROPERTIES NUMERICAL-SIMULATION DENSITY bULK FLOWAbILITY SEGREGATION bEHAVIOR

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Managing project risks and uncertainties

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Forest Ecosystems 2015年第1期2卷 31-44页

作者： mike Mentis business & the environment Postnet Suite 10102 Private Bag X7005 3650 Hillcrest South Africa

This article considers threats to a project slipping on budget,schedule and *** is used here as the collective for risks（quantifiable bad things that can happen）and uncertainties（poorly or not quantifiable bad possible events）.based on experience with projects in developing countries this review considers that（a）project slippage is due to uncertainties rather than risks,（b）while eventuation of some bad things is beyond control,managed execution and oversight are stil the primary means to keeping within budget,on time and fit-for-purpose,（c）improving project delivery is less about bigger and more complex and more about coordinated focus,effectiveness and developing thought-out heuristics,and（d）projects take longer and cost more partly because threat identification is inaccurate,the scope of identified threats is too narrow,and the threat assessment product is not integrated into overall project decision-making and *** by definition,what is poorly known is likely to cause *** it is not just the unquantifiability and intangibility of uncertainties causing project slippage,but that they are insufficiently taken into account in project planning and execution that cause budget and time *** project performance requires purpose-driven and managed deployment of scarce seasoned *** can be aided with independent oversight by deeply experienced panelists who contribute technical insights and can potentially show that diligence is seen to be done.

关键词： budget Fit-for-purpose Management Project Risks Schedule Threats Uncertainties

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cffdrs: an R package for the Canadian Forest Fire Danger Rating System

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Ecological Processes 2017年第1期6卷 30-40页

作者： Xianli Wang b.mike Wotton Alan S.Cantin Marc-AndréParisien Kerry Anderson brett Moore mike D.Flannigan Great Lakes Forestry Centre Canadian Forest ServiceNatural Resources Canada1219 Queen Street EastSault Ste.MarieON P6A 2E5Canada Department of Renewable Resources University of Alberta751 General Service BuildingEdmontonAB T6G 2H1Canada Faculty of Forestry University of Toronto33 Willcocks St.TorontoON M5S 3B3Canada Northern Forestry Centre Canadian Forest ServiceNatural Resources Canada5320-122nd StreetEdmontonAB T6H 3S5Canada

Introduction:The Canadian Forest Fire Danger Rating System(CFFDRS)is a globally known wildland fire risk assessment system,and two major components,the fire weather index system and the fire behavior prediction system,have been extensively used both nationally and internationally to aid operational wildland fire decision ***:In this paper,we present an overview of an R package cffdrs,which is developed to calculate components of the CFFDRS,and highlight some of its *** particular,we demonstrate how these functions could be used for large data *** and Discussion:With this cffdrs package,we provide a portal for not only a collection of R functions dealing with all available components in CFFDRS but also a platform for various additional developments that are useful for the understanding of fire occurrence and *** is the first time that all relevant CFFDRS methods are incorporated into the same platform,which can be accessed by both the management and research communities.

关键词： Fire behavior prediction system Fire weather index system Forest fire Forest fire risk Fuel moisture Landscape ecology

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Assessment of benefits and risks of growing Jatropha(Jatropha curcas) as a biofuel crop in sub-Saharan Africa: a contribution to agronomic and socio-economic policies

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Journal of Forestry Research 2018年第1期29卷 1-12页

作者： Keotshephile Kashe Donald L.Kgathi mike Murray-Hudson Kelebogile b.Mfundisi Okavango Research Institute University of Botswana

In sub-Saharan Africa（SSA）, the main goals behind the development of a biofuel industry are employment creation and income generation. Jatropha（Jatropha curcas L.） has emerged as a candidate for biodiesel production. It is a non-edible oil producing, drought-resistant plant that can be grown on marginal land with limited water and low soil fertility. However, these are also attributes that typify weedy and invasive plant species. Adding to these concerns are the general questioning of whether biofuel production will reduce Greenhouse gas（GHG）emissions globally. Currently, there is limited information on the potential invasiveness of many biofuel crops, and in particular, the potential risks of cultivating Jatropha. This paper aims to assess the benefits and risks, especially risks,of growing Jatropha for biodiesel production. Jatropha should be screened through a science-based risk-assessment procedure to predict the risk of becoming invasive before it is released for large-scale commercial *** net GHG savings can be achieved through the cultivation of Jatropha, considering two main factors： no landuse change and crop management without chemical fertilization.

关键词： biofuel Invasive Jatropha Risk

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Real-time Online Analysis of Power Grid

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CSEE Journal of Power and Energy Systems 2020年第1期6卷 236-238页

作者： mike Zhou Jianfeng Yan Xiaoxin Zhou China Electric Power Research Institute Beijing 100192China

The unprecedented operational complexity and se-curity risks in operating the Chinese UHV AC/DC power grid calls for a new generation of real-time(sec-order)online analysis systems to provide decision *** recent Digital Twin based online analysis research and development work to address the needs is *** addition,a high-level solution architec-ture for the future real-time online analysis systems is proposed for realizing:a)The delay of the virtual model to mirror the physical power grid is in sub-sec range;b)The downstream online analysis applications could have sec-order responsiveness.

关键词： Grid online analysis security assessment digital twin security constraint dispatching

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F4ESS-a framework for interdisciplinary data-driven earth system science

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International Journal of Digital Earth 2023年第1期16卷 3973-3986页

作者： Doris Dransch Daniel Eggert mike Sips Remote sensing and Geoinformatics Helmholtz Center Potsdam–German Research Center for GeosciencePotsdamGermany Geography Department Humboldt-University at BerlinBerlinGermany

Earth system science is an interdisciplinary effort to understand the fundamentals and interactions of environmental *** research is challenging since it demands the integration of scientific schemes and practices from different research fields into a collaborative work *** paper introduces the framework F4ESS that supports this integration.F4ESS provides methods and technologies that facilitate the development of integrative work environments for Earth system science.F4ESS enables scientists a)to outline structured and summarized descriptions of scientific procedures to facilitate communication and synthesis,b)to combine a large variety of distributed data analysis software into seamless data analysis chains and workflows,c)to visually combine and interactively explore the manifold spatiotemporal data and results to support understanding and knowledge *** F4ESS methods and technologies are generic and can be applied in various scientific *** discuss F4EsS in the context of the interdisciplinary investigation of flood events.

关键词： Earth system science interdisciplinary research scientific workflows integration

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Large-scale destress blasting for seismicity control in hard rock mines:A case study

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International Journal of Mining Science and Technology 2020年第2期30卷 141-149页

作者： Isaac Vennes Hani Mitri Damodara Reddy Chinnasane mike Yao Department of Mining and Materials Engineering McGill UniversityMontrealQuebec H3A 0E8Canada Copper Cliff Mine Vale Canada LtdSudbury P0M 1N0Canada

Destress blasting is a rockburst control technique where highly stressed rock is blasted to reduce the local stress and stiffness of the rock,thereby reducing its burst *** technique is commonly practiced in deep hard rock mines in burst prone developments,as well as in sill or crown pillars which become burst-prone as the orebody is ***-scale destressing is a variant of destress blasting where panels are created parallel to the orebody strike with a longhole,fanning blast pattern from cross cut drifts situated in the host *** aim of panel destressing is to reduce the stress concentration in the ore blocks or pillars to be *** paper focuses on the large-scale destress blasting program conducted at Vale's Copper Cliff Mine(CCM)in Ontario,*** merits of panel destressing are examined through field measurements of mining induced stress changes in the *** destressing mechanism is simulated with a rock fragmentation factor(a)and stress reduction/dissipation factor(b).A 3D model is built and validated with measured induced stress *** is shown that the best correlation between the numerical model and field measurements is obtained when the combination of a and b indicates that the blast causes high fragmentation(a=0.05)and high stress release(b=0.95)in the destress *** is demonstrated that the burst proneness of the ore blocks in the panel stress shadow is reduced in terms of the brittle shear ratio(bSR)and the burst potential index(bPI).

关键词： Destress blasting Preconditioning Rockbursts Strainbursts Numerical modeling

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The computerized LASSI-bC Test versus the Standard LASSI-L Paper-and-Pencil Version in Community-based-Samples

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Advances in Alzheimer's Disease 2024年第1期13卷 11-25页

作者： Rosie E. Curiel Cid Alexandra Ortega Ubbo Visser Marcela Kitaigorodsky D. Diane Zheng Diana Hincapie Kirsten Horne Crenshaw Ashleigh beaulieu brooke bosworth Liz Gallardo Emory Neer Sofia Ramirez Elizabeth A. Crocco mike Georgiou Efrosyni Sfakianaki David A. Loewenstein Center for Cognitive Neuroscience and Aging and Department of Psychiatry and behavioral Sciences Miller School of Medicine University of Miami Miami FL USA Department of Computer Sciences University of Miami Coral Gables FL USA Nova Southeastern University Fort Lauderdale FL USA Department of Radiology and Nuclear Medicine Miller School of Medicine University of Miami Miami FL USA

Proactive Semantic Interference (PSI) and failure to recover from PSI (frPSI), are novel constructs assessed by the LASSI-L. These measures are sensitive to cognitive changes in early Mild Cognitive Impairment (MCI) and preclinical AD determined by Aβ load using PET. The goal of this study was to compare a new computerized version of the LASSI-L (LASSI-brief Computerized) to the standard paper-and-pencil version of the test. In this study, we examined 110 cognitively unimpaired (CU) older adults and 79 with amnestic MCI (aMCI) who were administered the paper-and-pencil form of the LASSI-L. Their performance was compared with 62 CU older adults and 52 aMCI participants examined using the LASSI-bC. After adjustment for covariates (degree of initial learning, sex, education, and language of evaluation) both the standard and computerized versions distinguished between aMCI and CU participants. The performance of CU and aMCI groups using either form was relatively commensurate. Importantly, an optimal combination of Cued b2 recall and Cued b1 intrusions on the LASSI-bC yielded an area under the ROC curve of .927, a sensitivity of 92.3% and specificity of 88.1%, relative to an area under the ROC curve of .815, a sensitivity of 72.5%, and a specificity of 79.1% obtained for the paper-and-pencil LASSI-L. Overall, the LASSI-bC was comparable, and in some ways, superior to the paper-and-pencil LASSI-L. Advantages of the LASSI-bC include a more standardized administration, suitability for remote assessment, and an automated scoring mechanism that can be verified by a built-in audio recording of responses.

关键词： Mild Cognitive Impairment Proactive Semantic Interference LASSI-L Computerized Cognitive Assessment

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Nanjinganthus is an angiosperm,isn't it?

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China Geology 2020年第3期3卷 359-361页

作者： Qiang Fu Joséb.Diez mike Pole Manuel García-Ávila Xin Wang State Key Laboratory of Palaeobiology and Stratigraphy Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and PaleoenvironmentChinese Academy ofSciencesNanjing 210008China Departamento de Geociencias Universidad de VigoVigo 36200Spain Queensland Herbarium Mount Coot-tha RoadToowong QLD 4066Australia Department of Geology Northwest UniversityXi’an 710069China

Nanjinganthus is an Early Jurassic angiosperm recognized based on the study of over 200 ***,some other authors have misinterpreted these *** the authors try to remedy the problems,by pointing out the logical pitfalls in these publications and underscoring a long-used,workable criterion for early *** paper explains the cons and pros of this criterion,hoping to bring palaeobotany and plant taxonomy back to a consistent and practical *** is an angiosperm.

关键词： Angiosperms Flower Jurassic Logics Fossil Pitfall

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Fermion dynamical symmetry and strongly-correlated electrons:A comprehensive model of high-temperature superconductivity

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Frontiers of physics 2020年第4期15卷 35-99页

作者： mike Guidry Yang Sun Lian-Ao Wu Cheng-Li Wu Department of Physics and Astronomy Universilty of TenesseeKnorilleTN 37996USA School of Physics and Astronomy Shanghai Jiao Tong UniversityShanghai 200240China IKERbASQUE Basque Foundation for Science48011 BilbaoSpainand Department of Theoretical Physics and History of ScienceBasque Country University(EHU/UPV)Post Office Bor 64448080 BilbaoSpain Department of Physics Chung-Yuan Christian UniversityChungliTaiwan 320China

We review application of the SU(4)model of strongly-correlated electrons to cuprate and iron-based superconductors.A minimal self-consistent generalization of bCS theory to incorporate antiferromag-netism on an equal footing with pairing and strong Coulomb repulsion is found to account system-atically for the major features of high-temperature superconductivity,with microscopic details of the parent compounds entering only *** provides a systematic procedure to separate es-sential from peripheral,suggesting that many features exhibited by the high-Te data set are of interest in their own right but are not central to the superconducting *** generally,we propose that the surprisingly broad range of conventional and unconventional superconducting and superfluid behavior observed across many fields of physics results from the systemnatic appearance of similar al-gebraic structures for the emergent ffoctive Harmiltonians,even though the microscopic Harmiltonians of the corresponding parent states may differ radically from each other.

关键词： strongly-correlated electrons SU(4)model fermian dynamical symmetry high-temperature superconductivity

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