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Highly refractory Archaean peridotite cumulates:Petrology and geochemistry of the Seqi Ultramafic Complex,SW Greenland

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Geoscience Frontiers 2018年第3期9卷 689-714页

作者： Kristoffer Szilas Vincent van Hinsberg iain mcdonald Tomas Naeraa Hugh Rollinson Jacob Adetunji Dennis Bird Department of Geological Sciences Stanford University450 Serra MallStanfordCA 94305USA Department of Earth&Planetary Sciences McGill UniversityQuebecCanada Department of Geology Lund UniversitySovegatan 12223 62 LundSweden School of Earth and Ocean Sciences Cardiff UniversityMain BuildingCardiff CF10 3ATUnited Kingdom College of Science University of DerbyDerbyDE22 1GBUK

This paper investigates the petrogenesis of the Seqi Ultramafic Complex, which covers a total area of approximately 0.5 km^2. The ultramafic rocks are hosted by tonalitic orthogneiss of the ca. 3000 Ma Akia terrane with crosscutting granitoid sheets providing an absolute minimum age of 2978 ± 8 Ma for the Seqi Ultramafic Complex. The Seqi rocks represent a broad range of olivine-dominated plutonic rocks with varying modal amounts of chromite, orthopyroxene and amphibole, i.e. various types of dunite(s.s.),peridotite(s.l.), as well as chromitite. The Seqi Ultramafic Complex is characterised primarily by refractory dunite, with highly forsteritic olivine with core compositions having Mg# ranging from about 91 to 93. The overall high modal contents, as well as the specific compositions, of chromite rule out that these rocks represent a fragment of Earth's mantle. The occurrence of stratiform chromitite bands in peridotite, thin chromite layers in dunite and poikilitic orthopyroxene in peridotite instead supports the interpretation that the Seqi Ultramafic Complex represents the remnant of a fragmented layered complex or a magma conduit, which was subsequently broken up and entrained during the formation of the regional continental *** all of the characteristics of the Seqi Ultramafic Complex points to formation of these highly refractory peridotites from an extremely magnesian(Mg# ~ 80), near-anhydrous magma, as olivinedominated cumulates with high modal contents of chromite. It is noted that the Seqi cumulates were derived from a mantle source by extreme degrees of partial melting(>40%). This mantle source could potentially represent the precursor for the sub-continental lithospheric mantle(SCLM) in this region,which has previously been shown to be ultra-depleted. The Seqi Ultramafic Complex, as well as similar peridotite bodies in the Fiskefjord region, may thus constitute the earliest cumulates that formed during the large-scale melting event(s), which

关键词： North Atlantic Craton Archaean Dunite Platinum-group elements Ultra-depleted mantle Fiskefjord

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A machine learning approach for regional geochemical data:Platinum-group element geochemistry vs geodynamic settings of the North Atlantic Igneous Province

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Geoscience Frontiers 2021年第3期12卷 42-59页

作者： Jordan J.Lindsay Hannah S.R.Hughes Christopher M.Yeomans Jens C.Ø.Andersen iain mcdonald Camborne School of Mines University of ExeterPenryn CampusPenrynCornwall TR109FEUnited Kingdom School of Earth and Ocean Sciences Main CollegeCardiff UniversityPark PlaceCardiff CF103ATUnited Kingdom

Whilst traditional approaches to geochemistry provide valuable insights into magmatic processes such as melting and element fractionation,by considering entire regional data sets on an objective basis using machine learning algorithms(MLAs),we can highlight new facets within the broader data structure and significantly enhance previous geochemical *** platinum-group element(PGE)budget of lavas in the North Atlantic Igneous Province(NAIP)has been shown to vary systematically according to age,geographic location and geodynamic *** the large multi-element geochemical data set available for the region,MLAs were employed to explore the magmatic controls on these shifting *** key advantage of using machine learning in analysis is its ability to cluster samples across multi-dimensional(i.e.,multi-element)*** NAIP data set is manipulated using Principal Component Analysis(PCA)and t-Distributed Stochastic Neighbour Embedding(t-SNE)techniques to increase separability in the data alongside clustering using the k-means *** new multi-element classification is compared to the original geographic classification to assess the performance of both *** workflow provides a means for creating an objective high-dimensional investigation on a geochemical data set and particularly enhances the identification of metallogenic anomalies across the *** techniques used highlight three distinct multi-element end-members which successfully capture the variability of the majority of elements included as input *** end-members are seen to fluctuate in prominence throughout the NAIP,which we propose reflects the changing geodynamic environment and melting ***,the variability of Pt and Pd are not reflected in MLA-based clustering trends,suggesting that they vary independently through controls not readily demonstrated by the NAIP major or trace element data structure(i.e.,other proxies for magmatic differe

关键词： Platinum-group elements Machine learning Plume Geochemistry Metallogenesis Mantle

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Effect of Different Reinforcing Fillers on Properties,Interfacial Compatibility and Weatherability of Wood-plastic Composites

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Journal of Bionic Engineering 2019年第2期16卷 337-353页

作者： Xiaoqian Wang Zhiming Yu Armando G.mcdonald MOE Key Laboratory of Wooden Material Science and Application Beijing Forestry UniversityQinghua East Road No.35Beijing 100083China Renewable Materials Program Department of ForestRangelandand Fire SciencesUniversity of Idaho875 Perimeter Drive MS 1133MoscowIdaho 83844-1133USA

Utilization of biochar in plastic based blends offers a sustainable way to renewable materials as well as value-added use of wood *** investigate the interfacial compatibility and weatherability properties of biochar composites,four types of Wood-Plastic Composites(WPC)were prepared by an extrusion *** mechanical properties,water absorptions,thermal and viscoelastic properties,and rheological behavior of the composites were also *** decolorizing carbon(NA)composite melts showed the higher modulus and viscosity,indicating better melt *** NA composites performed the best in tensile properties(strength of 2&6 MPa and modulus of 3.4 GPa)and had strong interfacial interaction between particles and the *** degree of HDPE crystallinity in the biochar and carbon composites decreased relative to Douglas-fir(DF)composites,while the thermal properties of the composites improved compared with DF *** the water resistance,the DF composites displayed the highest water absorption(3.7%)and thickness swell(2.9%).During accelerated weathering tests,longer exposure time increased the color change and lightness,especially for DF *** and biochar composites resulted in improved *** study opens up a pathway to utilize effectively the renewable biochar as reinforcing filler in WPC in outdoor applications.

关键词： biochar interfacial compatibility accelerated weathering wood-plastic composites

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A bayesian optimisation methodology for the inverse derivation of viscoplasticity model constants in high strain-rate simulations

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Defence Technology（防务技术） 2022年第9期18卷 1563-1577页

作者： Shannon Ryan Julian Berk Santu Rana Brodie mcdonald Svetha Venkatesh Applied Artificial Intelligence Institute(A^(2)I^(2)) Deakin University75 Pigdons RdWaurn PondsVIC3216Australia Defence Science and Technology Group 506 Lorimer StreetFishermans BendVIC3207Australia

We present an inverse methodology for deriving viscoplasticity constitutive model parameters for use in explicit finite element simulations of dynamic processes using functional experiments, i.e., those which provide value beyond that of constitutive model development. The developed methodology utilises Bayesian optimisation to minimise the error between experimental measurements and numerical simulations performed in LS-DYNA. We demonstrate the optimisation methodology using high hardness armour steels across three types of experiments that induce a wide range of loading conditions: ballistic penetration, rod-on-anvil, and near-field blast deformation. By utilising such a broad range of conditions for the optimisation, the resulting constitutive model parameters are generalised, i.e., applicable across the range of loading conditions encompassed the by those experiments(e.g., stress states, plastic strain magnitudes, strain rates, etc.). Model constants identified using this methodology are demonstrated to provide a generalisable model with superior predictive accuracy than those derived from conventional mechanical characterisation experiments or optimised from a single experimental condition.

关键词： Constitutive modelling Finite element Bayesian optimisation Finite element model updating

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Socio-Economic Impact Assessment of Intelligent Transport Systems

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Tsinghua Science and Technology 2006年第3期11卷 339-350页

作者：隽志才吴建平 Mike mcdonald Institute of Transportation Studies Shanghai Jiao Tong University Shanghai 200052 China Department of Civil and Environmental Engineering University of Southampton Southampton SO17 1BJ UK

A general review of the socio-economic impact of the intelligent transport system （ITS） is presented with a case study to demonstrate the data envelopment analysis method. Cost-benefit analyses are still the dominant method for evaluating ITS and other transport engineering projects, while cost effective analyses and multi-criteria appraisals are widely used to define and prioritize objectives by providing useful information for the most promising policy decisions. Both cost-benefit analyses and a data envelopment analysis method are applied to analyze the socio-economic impact of convoy driving systems. The main findings are that a convoy provides a worthwhile benefit-cost ratio when more than 30% of the traffics in the convoys and the traffic load exceeds 5500 vehicles/h for a three-lane motorway. The results also show that for a fixed percentage of convoys, increased demand will increase the data envelopment analysis method relative efficiency and that the neglect of certain output indicators of an ITS may result in underestimation of the system effects.

关键词： socio-economic impacts assessment cost-benefit analysis data envelopment analysis intelligent transport system convoy driving

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A Comprehensive Evaluation of Tourism Climate Suitability in Qinghai Province, China

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Journal of Mountain Science 2012年第3期9卷 403-413页

作者： TANG Chengcai ZHONG Linshen KRISTEN mcdonald CHENG Shengkui Institute of Geographic Sciences and Natural Resources Research Chinese Academy of SciencesBeijing 100101China Graduate University of Chinese Academy of Sciences Beijing 100049China China Rivers Project OR 97405USA

Qinghai Province is an important component of the Qinghai-Tibet Plateau in China. Scientific evaluation of the suitability of Qinghai's climate for tourism can contribute to overcoming obstacles posed by climate on sustainable tourism development in Qinghai Province, including disparities between the low and high seasons, high altitude health concerns, and weather events. A tourism climate suitability evaluation model of the Qinghai-Tibet Plateau is constructed (Tourism Climate Suitability Index, or TCSI), and tourism climate suitability is comprehensively evaluated for Qinghai Province from climate data from 1960 to 2009. Results show that: (I) There is clear distributional characteristics of spatial-temporal variability of TCSI values in Qinghai Province. (II) Tourism climate suitability in Qinghai Province has significant seasonal and regional differences. The year is divided into a very suitable period (July and August), suitable tourism periods (from April and October), less suitable periods (From Nov to Mar). June to August is the most suitable tourism period in Qinghai. Qinghai Province is divided into five levels of tourism climate suitability: most suitable regions, very suitable regions, suitable regions, less suitable regions, and unsuitable region. (III) The key factor which influences regional differences in tourism climatic suitability is atmospheric oxygen. And the key factors which chiefly influence seasonal differences of tourism climate suitability are temperature and humidity, the wind chill factor, and barrier weather.

关键词： Tourism climate Tourism climatesuitability index (TCSI) Comprehensive evaluation Qinghai Province Qinghai-Tibet Plateau China

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Urban ecology for the urban century

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Ecosystem Health and Sustainability 2016年第7期2卷 21-23页

作者： Robert Ian mcdonald The Nature Conservancy 4245 North Fairfax DriveArlingtonVirginia 22203 USA

When I was being trained as an ecologist at the Duke University,urban ecology was a rare and somewhat obscure *** were few courses on urban ecology or sustainability offered at any major university,and few textbooks on the ***,urban ecology was seen almost as an *** was understood primarily as the study of the structure and function of more pristine *** this point of view,stud-ying the urban world and its interactions seemed somewhat perverse,like trying to infer the population biology of wild animals by watching the mating habitats of populations of animals in a zoo-you might learn some-thing,but it certainly did not seem the most efficient way to knowledge of the“natural”*** be an urban ecologist just a few decades ago implied a willingness to challenge one of the fundamental assumptions of ecology.

关键词： urban ecology somewhat

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Fusarium pseudograminearum and *** affect the root system architecture of bread wheat

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The Crop Journal 2023年第1期11卷 316-321页

作者： Ahmed Saad Jack Christopher Anke Martin Stephen mcdonald Cassandra Percy Centre for Crop Health University of Southern QueenslandToowoombaQLD 4350Australia University of Queensland Queensland Alliance for Agriculture and Food Innovation(QAAFI)Leslie Research FacilityToowoombaQLD 4350Australia

Yield losses of bread wheat due to crown rot can be more severe when drought conditions occur during the grain-filling *** architecture characteristics are important for soil exploration and belowground resource acquisition and are essential for adaptation to water-limited *** such as root angle,length and density have been strongly associated with acquisition efficiency and contribute to yield stability of the *** impact of crown rot pathogens on wheat root architecture is poorly *** examined differences in root angle,length and number,as well as dry root weight of the crown rot-susceptible bread wheat cultivar,Livingston inoculated with one of two crown rot pathogens Fusarium culmorum or Fusarium pseudograminearum in a transparent-sided root observation *** adverse impacts on plant health and growth were revealed by visual discolouration of the leaf sheaths;fresh and dry shoot weight;leaf area of the oldest and the youngest fully expanded leaf and leaf *** of most recorded root system measurements were reduced when inoculated with either *** or *** contrast,root angle was increased in the presence of *** but was not significantly changed by *** development of whiteheads and grain losses in bread wheat caused by crown rot have previously been associated with blockages of the vascular *** method employed here was able to identify differences in the pathogen impacts on roots,which were not detected using previous *** research indicates that in the presence of *** and *** infection,not only reductions in the size and biomass of the shoot system but also changes in the length,biomass and architecture of the root system could play an important role in yield loss.

关键词： Crown rot Root characteristics Livingston Wheat

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Management disclosure of risk factors and COVID‑19

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Financial Innovation 2023年第1期9卷 1557-1565页

作者： Tim Loughran Bill mcdonald University of Notre Dame Notre DameUSA

Public companies in the United States are required to file annual reports(i.e.,Form 10-K)and disclose,among other things,the risk factors that may harm their stock *** risk of a pandemic was well-known before the recent crisis,and we now know that the initial impact on many shareholders was significant and *** what extent did managers forewarn their shareholders about this valuation risk?We examine all 10-K filings from 2018,before any knowledge of the current pandemic,and find that less than 21%of them contain any reference to pandemic-related *** the management’s presumed in-depth knowledge of their business and the general awareness that pandemics have been identified as a significant global risk for at least the past decade,this number should have been *** find an unexpectedly posi-tive correlation(0.137)between the use of pandemic-related words in annual reports and realized stock returns during the actual pandemic at the industry *** industries most severely impacted by COVID-19 barely mentioned pandemic risk in their financial disclosures to shareholders,indicating that managers were ineffective in highlighting their exposure to pandemic risks to investors.

关键词： Pandemic COVID-19 Form 10-K Risk factors

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Joint Statement on COVID-19

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Engineering 2021年第3期7卷 273-274页

作者： Xiaohong Li Jim mcdonald John L.Anderson Presidents of Chinese Aeademy of Einginering(CAE)Royal Amdemy of Ergineering(RAErg) and US national Academy of Engineering(NAE)

Advances in engineering and technology have played an indispensable role in shaping social and economic development.A host of new global challenges have appeared,though,that must be addressed through engineering education,research,and *** address such challenges,the national academies of engineering of China,the United Kingdom,and the United States have jointly sponsored four Global Grand Challenges Summits(GGCS)since *** GGCS were launched to accelerate global engage-ment on the Grand Challenges for Engineering-14 goals for improving life on the planet-and encourage international collabo-rations to achieve them.

关键词： jointly Grand planet

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