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Magnetohydrodynamic‑based Internal Cooling System for a Ceramic Cutting Tool:Concept Design,Numerical Study,and Experimental Evalidation

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Nanomanufacturing and Metrology 2023年第4期6卷 60-80页

作者： john o’hara Fengzhou Fang Center of Micro/Nano Manufacturing Technology(MNMT-Dublin) University College DublinDublin 4Ireland State Key Laboratory of Precision Measuring Technology and Instruments Laboratory of Micro/Nano Manufacturing Technology(MNMT)Tianjin UniversityTianjin 300072China

The efective removal of the heat generated during mechanical cutting processes is crucial to enhancing tool life and produc-ing workpieces with superior surface *** internal cooling systems used in cutting inserts employ a liquid water-based solvent as the primary medium to transport the excess thermal energy generated during the cutting *** limitations of this approach are the low thermal conductivity of water and the need for a mechanical input to circulate the coolant around the inner chamber of the cutting *** this context,this paper proposes an alternative method in which liquid gallium is used as the coolant in combination with a magnetohydrodynamic(MHD)pump,which avoids the need for an external power *** computational fuid dynamics,we created a numerical model of an internal cooling system and then solved it under conditions in which a magnetic feld was applied to the liquid *** was followed by a simulation study performed to evaluate the efectiveness of liquid gallium over liquid *** results of experiments conducted under non-cooling and liquid gallium cooling conditions were analyzed and compared in terms of the tool wear *** results showed that after six machining cycles at a cutting speed Vc=250 m min−1,the corner wear VBc rate was 75µm with the coolant of and 48µm with the MHD-based coolant on,representing a decrease of 36%in tool *** Vc=900 m min−1,the corner wear VBc rate was 75µm with the coolant of and 246µm with the MHD-based coolant on,representing a decrease of 31%in tool *** external cooling using liquid water was added,the results showed at Vc=250 m min−1,the diference between the tool wear rate reduction with the internal liquid gallium coolant relative to the external coolant was 29%.When the cutting speed was increased to Vc=900 m min−1,the diference observed between the internal liquid gallium coolant relative to the external coolant was 16%.The study proves the feasibility of using liqu

关键词： Internal cooling Heat transfer Liquid metal Magnetic feld Cutting tool

Is lunar magma ocean (LMo) gone with the wind?

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National Science Review 2016年第1期3卷 12-15页

作者： Yaoling Niu michael J.o'hara Department of Earth Sciences Durham University Institute of oceanology Chinese Academy of Sciences

The Moon is the only natural satellite of the Earth,and has been the subject of numerous works of arts,literature,mythology,astrology and astronomy for *** scientific speculation of its origin has also been in the lit... 详细信息

关键词： Eu Is lunar magma ocean gone with the wind LMo ppm

Advances in micro cutting tool design and fabrication

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International Journal of Extreme Manufacturing 2019年第3期1卷 33-61页

作者： john o’hara Fengzhou Fang Center of Micro/Nano Manufacturing Technology(MNMT-Dublin) University College DublinDublinIreland State Key Laboratory of Precision Measuring Technology and Instruments Center of Micro/Nano Manufacturing Technology(MNMT)Tianjin UniversityTianjin 300072People’s Republic of China

Microcutting is a precision technology that offers flexible fabrication of microfeatures or complex three-dimensional components with high machining accuracy and superior surface *** technology may offer great potential as well as advantageous process capabilities for the machining of hard-to-cut materials,such as tungsten *** geometrical design and dimension of the tool cutting edge is a key factor that determines the size and form accuracy possible in the machined ***,the majority of commercial microtools are scaled-down versions of conventional macrotool *** approach does not impart optimal performance due to size effects and associated ***,in-depth analysis and implementation of microcutting mechanics and fundamentals are required to enable successful industrial adaptation in microtool design and fabrication *** paper serves as a review of recent microtool designs,materials,and fabrication *** of tool performance is discussed,and new approaches and techniques are *** particular focus is tool wear suppression in the machining of hard materials and associated process parameters,including internal cooling and surface patterning *** review concludes with suggestions for an integrated design and fabrication process chain which can aid industrial microtool manufacture.

关键词： micro cutting tool design fabrication wear surface patterning

Acute and chronic excitotoxicity in ischemic stroke and late-onset Alzheimer's disease

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Neural Regeneration Research 2025年第7期20卷 1981-1988页

作者： Shan Ping Yu Emily Choi michael QJiang Ling Wei Department of Anesthesiology Emory University School of MedicineAtlantaGAUSA Center for Visual and Neurocognitive Rehabilitation Atlanta Veterans Affairs Medical CenterDecaturGAUSA

Stroke and Alzheimer's disease are common neurological disorders and often occur in the same *** comorbidity of the two neurological disorders represents a grave health threat to older *** review presents a brief background of the development of novel concepts and their clinical *** activity of glutamatergic N-methyl-D-aspartate receptors and N-methyl-D-aspartate receptor-mediated Ca^(2+)influx is critical for neuronal *** ischemic insult induces prompt and excessive glutamate release and drastic increases of intracellular Ca^(2+)mainly via N-methyl-D-aspartate receptors,particularly of those at the extrasynaptic *** Ca^(2+)-evoked neuronal cell death in the ischemic core is dominated by necrosis within a few hours and days known as acute ***,mild but sustained Ca^(2+)increases under neurodegenerative conditions such as in the distant penumbra of the ischemic brain and early stages of Alzheimer's disease are not immediately toxic,but gradually set off deteriorating Ca^(2+)-dependent signals and neuronal cell loss mostly because of activation of programmed cell death *** on the Ca^(2+)hypothesis of Alzheimer's disease and recent advances,this Ca^(2+)-activated“silent”degenerative excitotoxicity evolves from years to decades and is recognized as a unique slow and chronic *** N-methyl-D-aspartate receptor subunit GluN3A,primarily at the extrasynaptic site,serves as a gatekeeper for the N-methyl-D-aspartate receptor activity and is neuroprotective against both acute and chronic *** stroke and Alzheimer's disease,therefore,share an N-methyl-D-aspartate receptor-and Ca^(2+)-mediated mechanism,although with much different time *** is thus proposed that early interventions to control Ca^(2+)homeostasis at the preclinical stage are pivotal for individuals who are susceptible to sporadic late-onset Alzheimer's disease and Alzheimer's disease-related

关键词： Ca^(2+)hypothesis cognitive deficits hyperactivity late-onset Alzheimer's disease neurodegeneration N-methyl-D-aspartate receptors N-methyl-D-aspartate receptor subunits pathogenesis preventive treatment

on localization with robust power control for safety critical wireless sensor networks

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控制理论与应用（英文版） 2011年第1期9卷 83-92页

作者： michael J. WALSH Anthony FEE john BARToN Brendan o'FLYNN Martin J. HAYES Cian o'MATHUNA Clarity Center for Web Technologies Microsystems Centre-Tyndall National Institute Lee MaltingsUniversity College CorkCorkIreland Wireless Access Research Center University of LimerickLimerickIreland

A hybrid methodology is proposed for use in low power, safety critical wireless sensor network applications, where quality-of-service orientated transceiver output power control is required to operate in parallel with radio frequency-based localization. The practical implementation is framed in an experimental procedure designed to track a moving agent in a realistic indoor environment. An adaptive time synchronized approach is employed to ensure the positioning technique can operate effectively in the presence of dataloss and where the transmitter output power of the mobile agent is varying due to power control. A deterministic multilateration-based positioning approach is adopted and accuracy is improved by filtering signal strength measurements overtime to account for multipath fading. The location estimate is arrived at by employing least-squares estimation. Power control is implemented at two separate levels in the network topology. First, power control is applied to the uplink between the tracking reference nodes and the centralized access point. A number of algorithms are implemented highlighting the advantage associated with using additional feedback bandwidth, where available, and also the need for effective time delay compensation. The second layer of power control is implemented on the uplink between the mobile agent and the access point and here quantifiable improvements in quality of service and energy efficiency are observed. The hybrid paradigm is extensively tested experimentally on a fully compliant 802.15.4 testbed, where mobility is considered in the problem formulation using a team of fully autonomous robots.

关键词： Wireless sensor network Power control Localization

An evaluation of visual and measurement-based methods for estimating deposited fine sediment

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International Journal of Sediment Research 2016年第4期31卷 368-375页

作者： Elizabeth Conroy Jonathan N.Turner Anna Rymszewicz michael Bruen john J.o'Sullivan Mary Kelly-Quinn School of Biology and Environmental Science University College Dublin School of Geography Planning and Environmental PolicyUniversity College Dublin UCD Dooge Centre for Water Resources Research School of CivilStructural and Environmental EngineeringUCD Earth InstituteUniversity College Dublin

A wide range of methods are commonly used to measure deposited fine sediment and quantify substrate quality in rivers as part of bioassessment or monitoring *** this laboratory-based experiment known amounts of three sediment types(sand,topsoil,peat) were added to mesocosms and four methods of measuring deposited fine sediment;turbidity,estimation of released sediment,Turner-Hillis deposited sediment sampler(DSS) and visual estimation of%surface cover were *** objective of the study was to evaluate which of these methods for estimating deposited sediment best discriminates between levels of deposited fine sediment added and assesses the effects of inter-observer variability between%surface cover *** turbidity measurement and the resuspension method were strongly related to levels of added sediment,it proved difficult using the two methods to resolve differences between adjacent levels of added sediment e.g.50 g and 100 *** cover estimations were also strongly related to added sediment levels and were better able to distinguish between adjacent levels of added ***,we found no significant differences between the%surface cover estimations between *** from this laboratory experiment strongly endorse the use of visual estimation of surface cover in field *** work evaluating the turbidity and resuspension methods under field conditions would also be beneficial.

关键词： Deposited fine sediment Sediment sampling Turbidity Re-suspension Visual estimation

Genitourinary toxicity after pelvic radiation:Prospective review of complex urological presentations

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Asian Journal of Urology 2024年第4期11卷 633-641页

作者： Rowan V.David Asif Islam john Miller michael E.o'Callaghan Arman A.Kahokehr Department of Urology Lyell McEwin HospitalElizabeth ValeAdelaideAustralia College of Medicine and Public Health Flinders UniversityBedford Park South AustraliaAdelaideAustralia

objectiveRecent randomised controlled trials underestimated the incidence of genitourinary (GU) complications occurring more than 5 years following pelvic radiotherapy. This study aimed to determine the burden of treatment at a single institution from late GU complications after pelvic *** prospective study of all presentations for GU complications following pelvic radiotherapy at a tertiary urology department between November 2018 and November 2019 was performed. Subgroup analyses was performed on patients with prostate cancer (PCa) with late toxicity to compare patient demographics, radiotherapy, complications, and management *** were 117 hospital encounters involving 46 patients with a 56.4% repeat encounter rate. Patients with PCa were the predominant group (n=39, 84.8%). External beam radiotherapy was the most common treatment modality (n=41, 89.1%). The median time from radiotherapy to encounter was 8 (range 0–23) years. Radiation-induced haemorrhagic cystitis was the most common presentation (n=70, 59.8%). Forty-four (42.7%) encounters for GU toxicity were managed operatively and 33 (32.0%) involved a non-operative procedure. Nine patients required packed red cell transfusion, with a total of 154 units transfused. Patients with PCa who presented with late GU toxicity had higher median Radiotherapy oncology Group grades (p=0.020), proportion of emergency admissions (p=0.047), and frequency of clot urinary retention (ponclusionThere is a high burden of elective and emergency urology workload attributed to late pelvic radiation toxicity. Late GU toxicity occurring ≥5 years after radiotherapy is common and often more severe.

关键词： Pelvic malignancy Radiotherapy Genitourinary toxicity Hospitalisation Secondary malignancy

Effect of dietary fiber and threonine content on intestinal barrier function in pigs challenged with either systemic *** lipopolysaccharide or enteric Salmonella Typhimurium

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Journal of Animal Science and Biotechnology 2020年第3期11卷 724-735页

作者： michael o.Wellington Kimberley Hamonic Jack E.C.Krone john K.Htoo Andrew G.Van Kessel Daniel A.Columbus Prairie Swine Centre Inc.SaskatoonSK S7H 5N9Canada Department of Animal and Poultry Science University of SaskatchewanSaskatoonSK S7N 5A8Canada Evonik Nutrition&Care GmbH Hanau-WolfgangGermany

Background:The independent and interactive effects of dietary fiber(DF)and threonine(Thr)were investigated in growing pigs challenged with either systemic *** lipopolysaccharide(LPS)or enteric Salmonella Typhimurium(ST)to characterise their effect on intestinal barrier ***:In experiment 1,intestinal barrier function was assessed via oral lactulose and mannitol(L:M)gavage and fecal mucin analysis in pigs challenged with *** LPS and fed low fiber(LF)or high fiber(HF)diets with graded dietary *** lactulose recovery and L:M ratio increased(Poculation period in LF fed pigs but not in HF fed *** mucin output was increased(Pompared to LF fed *** experiment 2,RT-qPCR,ileal morphology,digesta volatile fatty acid(VFA)content,and fecal mucin output were measured in Salmonella Typhimurium challenged pigs,fed LF or HF diets with standard or supplemented dietary *** inoculation increased(Poutput compared to the unchallenged *** Thr increased fecal mucin output in the HF-fed pigs(Fib×Thr;Poncentration in cecum and *** effect of either Thr or fiber on expression of gene markers was observed except a tendency(P=0.06)for increased MUC2 expression with the HF *** HF increased goblet cell numbers(Ponclusion:Dietary fiber appears to improve barrier function through increased mucin production capacity(i.e.,goblet cell numbers,MUC2 gene expression)and secretion(i.e.,fecal mucin output).The lack of effect of dietary Thr in Salmonella-challenged pigs provides further evidence that mucin secretion in the gut is conserved and,therefore,Thr may be limiting for growth under conditions of increased mucin production.

关键词： Barrier function E.coli lipopolysaccharide Fiber Goblet cells Mucin Salmonella Swine Threonine

Comparison of novel tools with traditional cognitive tests in detecting delirium in elderly medical patients

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World Journal of Psychiatry 2020年第4期10卷 46-58页

作者： David J Meagher Henry o’Connell Maeve Leonard olugbenga Williams Fahad Awan Chris Exton michael Tenorio Margaret o’Connor Colum P Dunne Walter Cullen john McFarland Dimitrios Adamis Cognitive Impairment Research Group Graduate Entry Medical SchoolUniversity of LimerickLimerick V94 YVHOIreland Department of Computer Sciences University of LimerickLimerick V94 YVHOIreland School of Medicine University College DublinDublin 4 D04 V1W8Ireland Sligo Mental Health Services BallytivanSligo F91 CD34Ireland

BACKGRoUND Efficient detection of delirium and comorbid delirium-dementia is a key diagnostic *** of new,efficient delirium-focused methods of cognitive assessment is a key challenge for improved detection of neurocognitive disorders in everyday clinical *** To compare the accuracy of two novel bedside tests of attention,vigilance and visuospatial function with conventional bedside cognitive tests in identifying delirium in older hospitalized *** 180 consecutive elderly medical inpatients(mean age 79.6±7.2;51%female)referred to a psychiatry for later life consultation-liaison service with delirium,dementia,comorbid delirium-dementia and cognitively intact *** were assessed cross-sectionally with conventional bedside cognitive tests[WoRLD,Months Backward test(MBT),Spatial span,Vigilance A and B,Clock Drawing test and Interlocking Pentagons test]and two novel cognitive tests[Lighthouse test,Letter and Shape Drawing test(LSD)-4].RESULTS Neurocognitive diagnoses were delirium(n=44),dementia(n=30),comorbid delirium-dementia(n=60)and no neurocognitive disorder(n=46).All conventional tests had sensitivity of>70%for delirium,with best overall accuracy for the Vigilance-B(78.3%),Vigilance-A(77.8%)and MBT(76.7%)*** sustained attention component of the Lighthouse test was the most distinguishing of delirium(sensitivity 84.6%;overall accuracy 75.6%).The LSD-4 had sensitivity of 74.0%and overall accuracy 74.4%for delirium *** tests allowed for enhanced sensitivity(>90%)and overall accuracy(≥75%)with the highest overall accuracy for the combination of MBT-Vigilance A and the combined Vigilance A and B tests(both 78.3%).When analyses were repeated for those with dementia,there were similar findings with the MBTVigilance A the most accurate overall combination(80.0%).Combining the Lighthouse-SA with the LSD-4,a fail in either test had sensitivity for delirium of 91.4 with overall accuracy of 74.4%.

关键词： Visuospatial function Attention Vigilance Letter and Shape Drawing test Lighthouse test Delirium Dementia Phenomenology Assessment