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Iron casting skin management in no-bake mould – Effects of magnesium residual level and mould coating

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China Foundry 2015年第3期12卷 222-230页

作者： Mihai Chisamera Nicoleta Ivan Iulian Riposan Stelian stan POLITEHNICA University of Bucharest

The relative performance of coatings for furan resin sand moulds [P-toluol sulphonic acid(PTSA) as hardener] [FRS-PTSA moulds], was compared by analyzing the surface layer for degenerated graphite in Mg treated iron with 0.020 wt.% to 0.054 wt.% Mgres. It was found that the iron nodularising potential(Mg, Ce, La content) and whether the mould coatings contained S, or were capable of desulphurizing were important factors. These moulds have S in the PTSA binder, which aggravates graphite degeneration in the surface layer, depending strongly on the Mgres with lower Mgres increasing the layer thickness. The application of a mould coating strongly influenced graphite deterioration in the surface layer of castings. It either promoted graphite degeneration to less compact morphologies when using S-bearing coatings, or conversely, limited the surface layer thickness using desulphurization type coatings. Independently of the S-source at the metal – mould interface, the presence of sulphur had an adverse effect on graphite quality at the surface of Mg-treated irons, but its negative effect could also reach the graphite phase within the casting section. If the coatings employed desulphurization materials, such as Mg O, or a mixture(Ca O + Mg O + Talc) or Mgbearing Fe Si, they protected the graphite shape, improving graphite nodularity, at the metal – mould interface, and so decreased the average layer thickness in FRS-PTSA moulds. Fe Si Mg was highly efficient in minimizing the casting skin by improving graphite nodularity. It is presumed that the Mg O or(Mg O + Ca O + Talc) based coatings acted to remove any S released by the mould media. The Mg-Fe Si coatings also reacted with S from the mould but additionally supplemented the Mg nodularising potential prior to solidification. This dual activity is achievable with coatings containing active magnesium derived from fine Mg-Fe Si materials.

关键词： ductile iron compacted graphite iron surface layer graphite degeneration resin bonded sand mould Mg-bearing mould coating S-bearing mould coating

Enhance Stability and in vitro Cell Response to a Bioinspired Coating on Zr Alloy with Increasing Chitosan Content

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Journal of Bionic Engineering 2017年第3期14卷 459-467页

作者： Daniela Ionita Maria Vardaki Miruna S. stan Anca Dinischiotu Ioana Demetrescu Faculty of Applied Chemistry and Materials Science University Politehnica of Bucharest 1-7 Polizu 011061 Bucharest Romania Department of Biochemistry and Molecular Biology Faculty of Biology University of Bucharest 91-95 Splaiullndependentei 050095 Bucharest Romania Academy of Romanian Scientist Splaiullndependentei 54 050094 Bucharest Romania

The aim of the present paper is to characterize bioinspired chitosan （CS）＋ hydroxyapatite （HA） coatings with various components ratio on a zirconium alloy with titanium. The coatings were characterized by FT-IR, SEM, hydrophilic/hydrophobic balance, adherence, roughness, electrochemical stability and in vitro cell response. Electrochemical tests, including potentio- dynamic polarization curves and electrochemical impedance spectroscopy, were performed in normal saline physiological solution. Cell viability of MC3T3-E1 osteoblasts, lactate dehydrogenase, nitric oxide, and Reactive Oxygen Species （ROS） levels, as well as actin cytoskeleton morphology, were evaluated as biological in vitro tests. The results on in vitro cell response indicated good cell membrane integrity and viability for all samples, but an increased cell number, a decreased ROS level and a better cytoskeleton organization were noticed for the sample with a higher CS content. The coating with highest CS concen- tration indicated the best performance based on the experimental data. The highest hydrophilic character, highest resistance to corrosion and best biocompatibility as well recommend this coating for bioapplications in tissue engineering.

关键词： ZrTi alloy bioinspired coating cells response electrochemical stability

A New Fuzzy Adaptive Algorithm to Classify Imbalanced Data

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Computers, Materials & Continua 2022年第1期70卷 73-89页

作者： Harshita Patel Dharmendra Singh Rajput Ovidiu Petru stan Liviu Cristian Miclea School of Information Technology&Engineering Vellore Institute of TechnologyVellore632014India Technical University of Cluj Napoca Faculty of Automation and Computer ScienceCluj Napoca400114Romania

Classification of imbalanced data is a well explored issue in the data mining and machine learning community where one class representation is overwhelmed by other *** Imbalanced distribution of data is a natural occurrence in real world datasets,so needed to be dealt with carefully to get important *** case of imbalance in data sets,traditional classifiers have to sacrifice their performances,therefore lead to *** paper suggests a weighted nearest neighbor approach in a fuzzy manner to deal with this *** have adapted the‘existing algorithm modification solution’to learn from imbalanced datasets that classify data without manipulating the natural distribution of data unlike the other popular data balancing *** K nearest neighbor is a non-parametric classification method that is mostly used in machine learning *** classification with the nearest neighbor clears the belonging of an instance to classes and optimal weights with improved nearest neighbor concept helping to correctly classify imbalanced *** proposed hybrid approach takes care of imbalance nature of data and reduces the inaccuracies appear in applications of original and traditional *** show that it performs well over the existing fuzzy nearest neighbor and weighted neighbor strategies for imbalanced learning.

关键词： Machine learning fuzzy classification nearest neighbor adaptive approach optimal weights

Thermal analysis control of in-mould and ladle inoculated grey cast irons

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China Foundry 2009年第2期6卷 145-151页

作者： Mihai Chisamera Iulian Riposan Stelian stan Eduard Stefan George Costache POLITEHNICA University of Bucharest 313 Spl.Independentei

The effect of addition of 0.05wt.% to 0.25 wt.% Ca,Zr,Al-FeSi alloy on in-ladle and in-mould inoculation of grey cast irons was *** the present paper,the conclusions drawn are based on thermal *** the solidification pattern,some specific cooling curves characteristics,such as the degree of undercooling at the beginning of eutectic solidif ication and at the end of solidifi cation,as well as the recalescence level,are identif ied to be more influenced by the inoculation *** degree of eutectic undercooling of the electrically melted base iron having 0.025% S,0.003% Al and 3.5% Ce is excessively high(39-40℃),generating a relatively high need for *** these conditions,the in-mould inoculation has a more signif icant effect compared to ladle inoculation,especially at lower inoculant usage(less than 0.20 wt.%).Generally,the eff iciency of 0.05wt.% -0.15wt.% of alloy for in-mould inoculation is comparable to,or better than,that of 0.15wt.% -0.25wt.% addition in ladle inoculation *** order to secure stable and controlled processes,representative thermal analysis parameters could be used,especially in thin wall grey iron castings production.

关键词： thermal analysis grey cast irons in-mould inoculation ladle inoculation I

Inside the Light Boojums: a Journey to the Land of Boundary Defects

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Analysis in Theory and Applications 2020年第2期36卷 128-160页

作者： stan Alama Lia Bronsard Petru Mironescu Department of Mathematics&Statistics McMaster UniversityHamiltonOntarioL8S 4K1 Canada Universit'e de Lyon CNRS UMR 5208Universit´e Lyon 1Institut Camille Jordan43 blvd.du 11 Novembre 1918F-69622 Villeurbanne CedexFrance

We consider minimizers of the energy Eε(u)=:∫Ω[1/2|■u|^2+1/4ε2(|u|^2-1)^2]dx+1/2ε^s∫■ΩW(u,g)ds,u:Ω→■,0-cosα)^2,0 详细信息

We consider minimizers of the energy Eε(u)=:∫Ω[1/2|■u|^2+1/4ε2(|u|^2-1)^2]dx+1/2ε^s∫■ΩW(u,g)ds,u:Ω→■,0-cosα)^2,0

关键词： Nematics thin-film limit Ginzburg-Landau type energy weak anchoring boundary vortices asymptotic profile

Impact of rewilding,species introductions and climate change on the structure and function of the Yukon boreal forest ecosystem

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Integrative Zoology 2018年第2期13卷 123-138页

作者： Rudy BOONSTRA stan BOUTIN Thomas S.JUNG Charles J.KREBS Shawn TAYLOR Department of Biological Sciences University of Toronto ScarboroughTorontoOntarioCanada Department of Biological Sciences University of AlbertaEdmontonAlbertaCanada Department of Environment Government of YukonWhitehorseYukonCanada Department of Zoology University of British ColumbiaVancouverBritish ColumbiaCanada

Community and ecosystem changes are happening in the pristine boreal forest ecosystem of the Yukon for 2 ***,climate change is affecting the abiotic environment(temperature,rainfall and growing season)and driving changes in plant productivity and predator-prey ***,simultaneously change is occurring because of mammal species reintroductions and *** key ecological question is the impact these faunal changes will have on trophic *** productivity in the boreal forest is increasing because of climatic warming,but plant species composition is unlikely to change significantly during the next 50-100 *** 9-10-year population cycle of snowshoe hares will persist but could be reduced in amplitude if winter weather increases predator hunting *** rodents have increased in abundance because of increased vegetation *** ground squirrels have disappeared from the forest because of increased predator hunting efficiency associated with shrub *** have occurred for 2 reasons:human reintroductions of large ungulates and natural recolonization of mammals and birds extending their geographic *** deliberate rewilding of wood bison(Bison bison)and elk(Cervus canadensis)has changed the trophic structure of this boreal ecosystem very *** natural range expansion of mountain lions(Puma concolor),mule deer(Odocoileus hemionus)and American marten(Martes americana)should have few ecosystem *** potential changes will require long-term monitoring studies and experiments on a scale we rarely deem *** affected by climate change,species reintroductions and human alteration of habitats cannot remain stable and changes will be critically dependent on food web interactions.

关键词： community stability introduced species population cycles trophic dynamics

Influencing factors on as-cast and heat treated 400-18 ductile iron grade characteristics

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China Foundry 2007年第4期4卷 300-303页

作者： I.Riposan M.Chisamera S.stan POLITEHNICA University BucharestRO-060042Romania

As-cast and heat-treated 400-18 ductile iron （DI） grade was obtained in different foundry conditions, as metallic charge, Mg-treatment alloy and inoculation. It was found that the Pearlitic Influence Factor （P） and Anti- nodulizing Complex Factor （K1） have an important influence on property of DI, depending on the Mn and P level, the metallurgical quality of iron melt, rare earth （RE） and inoculation. It was also found that the influence of Mn is depended on the phosphorus and residual elements level in ductile iron. Less than 0.03%P and 0.2%Mn and P〈2.0 are the basic conditions to obtain as-cast ferritic structure. At the same lower level of Mn and P, the increasing of residual elements （P〉2.0） determines presence of pearlite in as-cast structure, while ferrite structure is obtained after a short annealing heat treatment. Lower level of phosphorus （P〈0.025%） and residual elements （Px〈2.0） allow to use relative high Mn content （0.32%-0.38%）, in condition of ferritic structure, including in as-cast state. High P （0.04%- 0.045%） and Mn （0.25%-0.35%） content stabilized peadite, especially at lower level of residual elements （P 〈2.0）. Antinodulizing action of elements was counteracted up to K1=2.0 level, by RE included in Mg-treatment alloy, which are beneficial for K1〈1.2 and compulsory for K1〉1.2. Si has a significant influence on the mechanical properties of heat treated ductile irons： an important decreasing of elongation level and a moderate increasing of yield and tensile strength and their ratio in 150-170 HB typical hardness field. A typical final chemical composition for as-cast 400-18 ductile iron could include 3.5%-3.7%C, 2.4%-2.5%Si, max.0.18%Mn, max.0.025%P, max.0.01%S, 0.04%-0.05%Mg for Px〈1.5 and K1〈1.1. High purity pig iron, RE-bearing FeSiMg and powerful inoculant are also recommended.

关键词： ductile iron 400-18 grade metallic charge pearliUc and anti-nodulizing factors chemistry

Good accuracy of the alpha-defensin lateral flow test for hip periprosthetic joint infection: A pilot study in a retrospective cohort of 52 patients

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World Journal of Orthopedics 2020年第1期11卷 36-46页

作者： Jesse WP Kuiper Pieter Pander stan J Vos Department of Orthopedic Surgery Noordwest ZiekenhuisgroepAlkmaar 1815 JDNetherlands Centre for Orthopedic Research Alkmaar Noordwest ZiekenhuisgroepAlkmaar 1815 JDNetherlands

BACKGROUND The alpha-defensin lateral flow(ADLF)test is a new diagnostic tool for periprosthetic joint infection(PJI).Test accuracy for combined cohorts of hip and knee PJI has been reported to be *** To assess the accuracy of the ADLF test for hip PJI,and to compare three different diagnostic criteria for *** A cohort of 52 patients was identified,with a painful or poor-functioning total hip-or hemi-arthroplasty,that underwent aspiration and a subsequent ADLF *** was diagnosed with Musculoskeletal Infection Society(MSIS)criteria,and sensitivity,specificity,overall accuracy,positive predictive value and negative predictive value were ***,test specifics were compared with the European Bone and Joint Infection Society(EBJIS)and 2018 International Consensus Meeting(ICM)criteria for *** Using MSIS criteria,sensitivity was 100%(CI:54%-100%)and specificity was 89%(CI:76%-96%).Six true positives and 5 false positives were found,including one case of *** EBJIS criteria,more PJIs were found(11 vs 6),sensitivity was lower(71%,CI:42%-92%)and specificity was higher(97%,CI:86%-100%),with 4 false negatives and one false positive *** 2018 ICM criteria,sensitivity was 91%(62%-100%)and specificity 100%(91%-100%).The results in this cohort are comparable to previous *** Overall test accuracy of the ADLF test was good in this cohort,with a sensitivity of 100%and specificity of 89%.Using different PJI definition criteria,sensitivity and specificity changed slightly but overall accuracy remained around 90%.Using the ADLF test in metallosis cases can result in false positive results and should be performed with caution.

关键词： Periprosthetic Arthroplasty Replacement Hip Infection Periprosthetic joint infection Alpha-defensin Synovasure

Impact of climate change on the small mammal community of the Yukon boreal forest

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Integrative Zoology 2019年第6期14卷 528-541页

作者： Charles J.KREBS Rudy BOONSTRA BScott GILBERT Alice J.KENNEY stan BOUTIN Department of Zoology University of British ColumbiaVancouverBritish ColumbiaCanada Department of Biological Sciences University of Toronto ScarboroughTorontoOntarioCanada Renewable Resources Management Program Yukon CollegeWhitehorseYukonCanada Department of Biological Sciences University of AlbertaEdmontonAlbertaCanada

Long-term monitoring is critical to determine the stability and sustainability of wildlife populations,and if change has occurred,*** have followed population density changes in the small mammal community in the boreal forest of the southern Yukon for 46 years with density estimates by live trapping on 3-5 unmanipulated grids in spring and *** community consists of 10 species and was responsible for 9%of the energy flow in the herbivore component of this ecosystem from 1986 to 1996,but this increased to 38%from 2003 to *** mammals,although small in size,are large in the transfer of energy from plants to predators and *** species form the bulk of the *** was a shift in the dominant species from the 1970s to the 2000s,with Myodes rutilus increasing in relative abundance by 22%and Peromyscus maniculatus decreasing by 22%.From 2007 to 2018,Myodes comprised 63%of the catch,Peromyscus 20%,and Microtus species 17%.Possible causes of these changes involve climate change,which is increasing primary production in this boreal forest,and an associated increase in the abundance of 3 rodent predators,marten(Martes americana),ermine(Mustela ermine)and coyotes(Canis latrans).Following and understanding these and potential future changes will require long-term monitoring studies on a large scale to measure metapopulation *** small mammal community in northern Canada is being affected by climate change and cannot remain sta*** will be critically dependent on food-web interactions that are species-specific.

关键词： community change long-term study population cycles trophic dynamics voles