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Revealing the residual stress distribution in laser welded Eurofer97 steel by neutron diffraction and Bragg edge imaging

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journal of Materials Science & Technology 2022年第19期114卷 249-260页

作者： Bin Zhu Nathanael Leung Winfried Kockelmann Saurabh Kabra andrew jLondon Michael Gorley Mark jWhiting Yiqiang Wang Tan Sui School of Mechanical Engineering Sciences University of SurreyGuildfordSurrey GU27XHUnited Kingdom Science and Technology Facilities Council(STFC)Rutherford Appleton Laboratory ISIS FacilityHarwell OX110QXUnited Kingdom United Kingdom Atomic Energy Authority Culham Centre for Fusion EnergyCulham Science CentreAbingdonOxon OX143DBUnited Kingdom

Eurofer97 steel is a primary structural material for applications in fusion reactors. Laser welding is a promising technique to join Eurofer97 plasma-facing components and overcome remote handling and maintenance challenges. The interaction of the induced residual stress and the heterogeneous microstructure degrades the mechanical performance of such fusion components. The present study investigates the distribution of residual stress in as-welded and post-heat treated Eurofer97 joints. The mechanistic connections between microstructure, material properties, and residual stress are also studied. Neutron diffraction is used to study the through-thickness residual stress distribution in three directions,and neutron Bragg edge imaging(NBEI) is applied to study the residual strain in high spatial *** microstructures and micro-hardness are characterised by electron backscatter diffraction and nanoindentation, respectively. The M-shaped residual stress distribution through the thickness of the as-welded weldment is observed by neutron diffraction line scans over a region of 1.41 × 10 mm^(2). These profiles are cross-validated over a larger area(∼56 × 40 mm^(2)) with the higher spatial resolution by NBEI. The micro-hardness value in the fusion zone of the as-welded sample almost doubles from 2.75 ± 0.09 GPa to 5.06 ± 0.29 GPa due to a combination of residual stress and cooling-induced martensite. Conventional post weld heat treatment(PWHT) is shown to release ∼90% of the residual stress but not fully restore the microstructure. By comparing its hardness with that of stress-free samples, it is found that the microstructure is the primary contribution to the hardening. This study provides insight into the prediction of structural integrity for critical structural components of fusion reactors.

关键词： Laser-welded Eurofer97 steel Residual stress Neutron diffraction Neutron Bragg edge imaging Nanoindentation EBSD

Trends in characteristics of neurologists who provide stroke consultations in the USA,2008-2021

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Stroke & Vascular Neurology 2023年第1期8卷 86-88页

作者： Carter H Nakamoto andrew D Wilcock Lee H Schwamm jennifer j Majersik Kori S Zachrison Ateev Mehrotra Department of Health Care Policy Harvard Medical SchoolBostonMassachusettsUSA Department of Family Medicine University of Vermont Larner College of MedicineBurlingtonVermontUSA Department of Neurology Massachusetts General HospitalBostonMassachusettsUSA Department of Neurology University of UtahSalt Lake CityUtahUSA Department of Emergency Medicine Massachusetts General HospitalBostonMassachusettsUSA Division of General Medicine and Primary Care Beth Israel Deaconess Medical CenterBostonMassachusettsUSA

Introduction Patients with acute ischaemic strokes(AIS),on average,fare better with timely neurologist consultation,and a growing proportion of them receive ***,little is known about trends in the characteristics of neurologists who treat *** We identified AIS and transient ischaemic attack(TIA)episodes with neurologist consults in fee-for service Medicare from january 2008 to September *** each episode,we determined whether the neurologist was a vascular neurologist,was a high-volume provider,whether the patient was transferred between hospitals and the distance between the patient’s home and physician’s *** From 2008 to 2021,the share of AIS/TIA episodes(n=5073294)with neurologist consults increased(52.9%to 61.7%).Among episodes with consults,the fraction conducted by a vascular neurologist(5.2%to 13.7%)or by a high-volume neurologist(13.2%to 14.9%)also *** fraction with the patient’s home and neurologist greater than 100 miles apart(4.8%to 9.6%)or in different states(5.1%to 8.1%)increased,as did the fraction with transfers(4.2%to 8.5%).Discussion Over the study period,the proportion of AIS/TIA episodes with consultations from neurologists with either vascular neurology certifications or high volumes increased substantially.

关键词： acute characteristics consultation

Bio-Imitation of Mexican Migration Routes to the USA with Slime Mould on 3D Terrains

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journal of Bionic Engineering 2013年第2期10卷 242-250页

作者： andrew Adamatzky Genaro j Martinez Department of Computer Sciences University of the West of England Bristol BS16 1QY UK Escuela Superior de Computo Instituto Politecnico Nacional Mexico

Plasmodium ofPhysarum polycephalum （P. polycephalum） is a large single cell visible by an unaided eye. It shows sophisticated behavioural traits in foraging for nutrients and developing an optimal transport network of protoplasmic tubes spanning sources of nutrients. When placed in an environment with distributed sources of nutrients the cell computes＇ an optimal graph spanning the nutrients by growing a network of protoplasmic tubes. P. polycephalum imitates development ofman-made transport networks of a country when configuration of nutrients represents major urban areas, We employed this feature of the slime mould to imitate mexican migration to USA. The Mexican migration to USA is the World＇s larger migration system. We bio-physically imitated the migration using slime mould P. poIycephalum. In laboratory experiments with 3D Nylon terrains of USA we imitated development of migratory routes from Mexico-USA border to ten urban areas with high concentration of Mexican migrants. From results of laboratory experiments we extracted topologies of migratory routes, and highlighted a role of elevations in shaping the human movement networks.

关键词： biomimetics bio-inspired computing migration routes slime mould

The ethical cost of doing nothing

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National Science Review 2020年第7期7卷 1260-1262页

作者： andrew j.Parker University of Oxford Department of PhysiologyAnatomy and Genetics

Concern has been raised about the ethics and risks of performing genetic interventions in macaque monkeys to study models of human neuropsychiatric conditions. Here I point out that,when the outcome of some situations is truly uncertain, human decision makers tend to evaluate these situations inconsistently. The consequences of this inconsistency are sometimes profound, as they lead policy makers and reviewers to ignore or discount the ethical costs of doing nothing. I conclude that there are fundamental problems with the ‘precautionary

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Testing decreasing variabililty of cockroach forewings through time using four Recent species： Blattella germanica, Polyphaga aegyptiaca, Shelfordella lateralis and Blaberus craniifer, with implications for the study of fossil cockroach forewings

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Insect Science 2012年第2期19卷 129-142页

作者： andrew j. Ross Department of Natural Sciences National Museums Scotland Edinburgh UK

Vrsansky, （2000） considered there is decreasing variability in the forewings of cockroaches through time, based on a study of fossil and Recent species. This study tests his theory, based on a study of four Recent species of cockroaches： Blattella germanica （Blattellidae）, Polyphaga aegyptiaca （Polyphagidae）, Shelfordella lateralis （Blattidae） and Blaberus craniifer （Blaberidae）. The new results, based on the coefficient of variation （CV） of the number of veins, indicate that Recent species can be more variable than fossil species and therefore do not support the theory. The results also show that at least 30 complete wings of the same species are required for a reliable CV value that is compa- rable between species.

关键词： Blaberidae Blattellidae Blattidae cockroach Polyphagidae variation

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自然资源保护与管理中的分子方法

国外科技新书评介 2011年第2期 11-12页

作者： j.andrew Dewoody

近年来，分子遗传学和基因组学的成果大大帮助了野生资源管理的专家们。今天，几个主要的有关保护和管理的杂志，都有专门的遗传学编辑来处理有关分子数据的文章。本书编辑的目的就是希望把自然资源管理和分子标记的内容整合到一起；

关键词：自然资源管理自然资源保护分子遗传学基因组学分子数据分子标记编辑

Keeping an ear out:size relationship of the tympanic bullae and pinnae in bandicoots and bilbies(Marsupialia:Peramelemorphia)

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Current Zoology 2022年第3期68卷 251-264页

作者： Melissa C.TAYLOR Kenny j.TRAVOUILLON Margaret E.andrew Patricia A.FLEMING Natalie M.WARBURTON Terrestrial Ecosystem Science and Sustainability Harry Butler InstituteMurdoch University90 South StMurdochWA 6150Australia Collections and Research Western Australian MuseumWelshpoolWA 6106Australia

Bandicoots and bilbies(Order Peramelemorphia)occupy a broad range of habitats across Australia and New Guinea,from open,arid deserts to dense *** once diverse group has been particularly vulnerable to habitat loss and introduced eutherian predators,and numerous species extinctions and range retractions have *** reasons for this loss requires greater understanding of their *** of the pinnae and tympanic bullae varies markedly among *** hearing is important for both predator avoidance and prey location,the variability in ear morphology could reflect specialization and adaptation to specific environments,and therefore be of conservation *** measured 798 museum specimens representing 29 species of *** for phylogenetic relatedness and head length,pinna surface area was weakly negatively correlated with average precipitation(rainfall being our surrogate measure of vegetation productivity/complexity),and there were no environmental correlates with effective diameter(pinna width).Controlling for phylogenetic relatedness and skull length,tympanic bulla volume was negatively correlated with *** that inhabited drier habitats,which would be open and allow sound to carry further with less obstruction,had relatively larger pinnae and tympanic *** contrast,species from higher rainfall habitats,where sounds would be attenuated and diffused by dense vegetation,had the smallest pinnae and bullae,suggesting that low-frequency hearing is not as important in these *** with temperature did not reach statistical *** findings highlight linkages between hearing traits and habitat that can inform conservation and management strategies for threatened species.

关键词： external ear hearing ecology marsupial middle ear sound perception

Advances in diagnostic testing for gastroesophageal reflux disease

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World journal of Gastroenterology 2010年第30期16卷 3750-3756页

作者： andrew j Gawron Ikuo Hirano Division of Gastroenterology Department of MedicineNorthwestern University Feinberg School of MedicineChicagoIL 60611-2951United States

Gastroesophageal reflux disease (GERD) contributes substantially to morbidity and to costs in the United States health care system. The burden of this disease has resulted in attempts at improving diagnosis and characterizing patients. Numerous research and technical advances have enhanced our understanding of both the utility and limitations of a variety of diagnostic modalities. The purpose of this review is to highlight recent advances in GERD diagnostic testing and to discuss their implications for use in clinical practice. Topics addressed include esophageal pH monitoring, impedance testing, symptom association analyses, narrow-band imaging, and histopathology.

关键词： Gastroesophageal reflux disease pH impedance pH monitoring Symptom association

Teleseismic waves reveal anisotropic poroelastic response of wastewater disposal reservoir

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Earth and Planetary Physics 2021年第6期5卷 547-558页

作者： andrew j Barbour Nicholas M Beeler u.s.geological survey earthquake science centerusa

Connecting earthquake nucleation in basement rock to fluid injection in basal,sedimentary reservoirs,depends heavily on choices related to the poroelastic properties of the fluid-rock system,thermo-chemical effects *** constraints on these parameters outside of laboratory settings are rare,and it is commonly assumed that the rock layers are *** the Arbuckle wastewater disposal reservoir in Osage County,Oklahoma,high-frequency formation pressure changes and collocated broadband ground velocities measured during the passing of large teleseismic waves show a poroelastic response of the reservoir that is both azimuthally variable and anisotropic;this includes evidence of static shifts in pressure that presumably relate to changes in local *** azimuthal dependence in both the static response and shear coupling appears related to tectonic stress and strain indicators such as the orientations of the maximum horizontal stress and faults and *** dynamic strains from a nearby borehole strainmeter,we show that the ratio of shear to volumetric strain coupling is~0.41 which implies a mean Skempton's coefficient of A=0.24 over the plausible range of the undrained Poisson's *** these observations are made at relatively low confining pressure and differential stress,we suggest that the hydraulically conductive fracture network is a primary control on the coupling between pore pressure diffusion and elastic stresses in response to natural or anthropogenic sources.

关键词： poroelasticity dynamic strain anisotropy wastewater disposal Oklahoma induced seismicity