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A CFD study on the hydrodynamic response of a small-scale ice floe induced by a passing ship

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Journal of Hydrodynamics 2024年第2期36卷 290-299页

作者： Zongyu Jiang Spyros Hirdaris Sasan Tavakoli Mikko Suominen pentti Kujala Marine and Arctic Technology Department of Mechanical EngineeringAalto UniversityEspooFinland Global Ship Systems Centre ABS Hellenic SM LLC.AthensGreece Department of Infrastructure Engineering The University of MelbourneMelbourneAustralia

A Reynolds averaged Navier-Stokes(RANS)computational fluid dynamics(CFD)model is built to investigate the hydrodynamic response of a circular ice floe under the influence of a passing ship in calm *** ship,mirroring the KRISO Container Ship’s hull design,progresses near an ice floe whose diameter is 30%of the ship’s length and its thickness is 3 *** ship advances at a constant speed,which is handled by using the overset mesh *** study focuses on the ice floe’s motions and the hydrodynamic forces induced by three speeds and three transverse distances of the passing *** reveal that ship-generated wakes notably influence the ice floe’s motions,with a greater influence on sway than ***,the ship’s speed and proximity distinctly affect the ice floe’s motions.

关键词： Hydrodynamics ship-ice interactions ice floe Reynolds averaged Navier-Stokes(RANS)computational fluid dynamics(CFD)

Short-day treatment during the growing period limits shoot growth and increases frost hardiness of hybrid aspen plants in the nursery

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Forestry Studies in China 2007年第4期9卷 262-266页

作者： Zhang Gang jaana Luoranen Heikki Smolander College of Horticulture Agricultural University of Hebei Baoding 071001 Hebei P. R. China The Finnish Forest Research Institute Suonenjoki Research Unit Juntintie 154 FIN-77600 Suonenjoki Finland

In Finland, under nursery conditions hybrid aspen may continue their shoot growth until early September. Thus, frost hardening is usually delayed. To solve this problem, we used a three-week period of short-day （SD） treatment between late July and mid-August. During autumn after frost exposure, frost hardiness （FH） was assessed three times with a stem-browning test. The resuits showed that after SD treatment shoot growth ceased and FH increased when compared to untreated hybrid aspen. Furthermore, the height of SD-treated hybrid aspen varied much less than that of the control plants. We conclude that SD treatment in the nursery during the growing period can be used as a supplementary method for producing well-hardened and uniform hybrid aspen plants.

关键词： frost hardiness nursery performance Populus shoot elongation short-day treatment

Crystallographic Analysis of Isothermally Transformed Bainite in 0.2C-2.0Mn-1.5Si-0.6Cr Steel Using EBSD

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Journal of Materials Science & Technology 2013年第4期29卷 359-366页

作者： Pasi P.Suikkanen Cyril Cayron Anthony J.DeArdo L.pentti Karjalainen Ruukki Metals Oy Rautaruukintie 155P.O.Box 93FI-92101 RaaheFinland Department of Mechanical Engineering University of OuluP.O.Box 420090014 University of OuluFinland Ruukki Metals Oy Rautaruukintie 155P.O.Box 93FI-92101 RaaheFinland. CEA LITEN17 rues des Martys38054 GrenobleFrance Department of Mechanical Engineering and Materials Science University of Pittsburgh848 Benedum HallPittsburghPA 15261-2285USA

The crystallography of bainite, transformed isothermally at 450 ℃ in 0.2C-2.0Mn-1.5Si-0.6Cr steel, was investigated by electron backscatter diffraction （EBSD） analysis. The orientation relationship （OR） was found to be closer to Nishiyama-Wassermann （N-W） than Kurdjumov-Sachs orientation relationship. Bainite microstructure consisted of parallel laths forming a morphological packet structure. Typically, there were three different lath orientations in a morphological packet. These orientations were dictated by a three specific N-W OR variants sharing the same {111} austenite plane. A packet of bainite laths with common {111} austenite plane was termed as crystallographic packet. Generally, the crystallographic packet size corresponded to the morphological packet size. Locally, crystallographic packets with only two dominant orientations were observed. This indicates strong local variant selection during isothermal bainite transformation. The relative orientation between the variants in crystallographic packets was found to be near 60°/〈110〉. This appears to explain the strong peak observed in the grain boundary misorientation distribution near 60°. Bainite also contained pronounced fraction of boundaries with their misorientation in the range of 2.5°-8° with quite widely dispersed rotation angles. Spatially these boundaries were found to locate inside the bainite laths, forming lath-like sub-grains.

关键词： Bainite Austenite Nishiyama-Wassermann orientation relationship Electron backscatter diffraction OEBSD) Crystallography Packet

Crystallographic Analysis of Martensite in 0.2C-2.0Mn-1.5Si-0.6Cr Steel using EBSD

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Journal of Materials Science & Technology 2011年第10期27卷 920-930页

作者： Pasi P.Suikkanen Cyril Cayron Anthony J.DeArdo L.pentti Karjalainen Department of Mechanical Engineering University of OuluBox 420090014 University of Oulu CEA LITEN17 rues des Martys38054GrenobleFrance Department of Mechanical Engineering and Materials Science University of Pittsburgh

The crystallography of martensite formed in 0.2C-2.0Mn-1,5Si-0.6Cr steel was studied using the electron backscattered diffraction （EBSD） technique. The results showed that the observed orientation relationship （OR） was closer to that of Nishiyama-Wassermann （N-W） than Kurdjumov-Sachs. The martensite consisted of parallel laths forming morphological packets. Typically, there were three different lath orientations in a morphological packet consisting of three specific N-W OR variants sharing the same {111} austenite plane. A packet of martensite laths with a common {111} austenite plane was termed a crystallographic packet. Generally, the crystallographic packet size corresponded to the morphological packet size, but occasionally the morphological packet was found to consist of two or more crystallographic packets. Therefore, the crystallographic packet size appeared to be finer than the morphological packet size. The relative orientation between the variants in crystallographic packets was found to be near 60°〈110〉, which explains the strong peak observed near 60° in the grain boundary misorientation distribution. Martensite also contained a high fraction of boundaries with a misorientation in the range 2.5-8°. Typically these boundaries were found to be located inside the martensite laths forming sub-laths.

关键词： Martensite Austenite Nishiyama-Wassermann orientation relationship EBSD Crystallography Packet

Low trypsinogen-1 expression in pediatric ulcerative colitis patients who undergo surgery

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World Journal of Gastroenterology 2013年第21期19卷 3272-3280页

作者： Maija Piekkala jaana Hagstrm Maarit Tanskanen Risto Rintala Caj Haglund Kaija-Leena Kolho Children's Hospital University of HelsinkiFIN-00029 HUSHelsinkiFinland Department of Pathology Haartman InstituteUniversity of HelsinkiFIN-00029 HUS HelsinkiFinland Department of Surgery Helsinki University Central HospitalFIN-00029 HUS HelsinkiFinland

AIM: To investigate whether matrix metalloproteinases-9 (MMP-9) or trypsinogens could serve as histological markers for an aggressive disease course in pediatric ulcerative colitis (UC). METHODS: We identified 24 patients with pediatric onset (≤ 16 years) UC who had undergone surgery during childhood/adolescence a median of 2.1 years (range 0.1-7.4 years) after the diagnosis (between 1990 and 2008) in Children's Hospital, Helsinki, Finland. We also identified 27 conservatively treated UC patients and matched them based on their age at the time of diagnosis and follow-up at a median of 6 years (range 3-11 years) to serve as disease controls. Twenty children for whom inflammatory bowel disease (IBD) had been excluded as a result of endoscopy served as non-IBD controls. Colon biopsies taken by diagnostic endoscopy before the onset of therapy were stained using immunohistochemistry to study the expression of MMP-9, trypsinogen-1 (Tryp-1), Tryp-2, and a trypsin inhibitor (TATI). The profiles of these proteases and inhibitor at diagnosis were compared between the surgery group, the conservatively treated UC patients and the non-IBD controls. RESULTS: The proportions of Tryp-1 and Tryp-2 positive samples in the colon epithelium and in the inflammatory cells of the colon stroma were comparable between the studied groups at diagnosis. Interestingly, the immunopositivity of Tryp-1 (median 1; range 0-3) was significantly lower in the epithelium of the colon in the pediatric UC patients undergoing surgery when compared to that of the conservatively treated UC patients (median 2; range 0-3; P = 0.03) and non-IBD controls (median 2; range 0-3; P = 0.04). For Tryp-2, there was no such difference. In the inflammatory cells of the colon stroma, the immunopositivities of Tryp-1 and Tryp-2 were comparable between the studied groups at diagnosis. Also, the proportion of samples positive for TATI, as well as the immunopositivity, was comparable between the studied groups in the colon ep

关键词： Children Ulcerative colitis Inflammatory bowel disease Matrix metalloproteinase-9 resection Trypsin inhibitor

Lanthanide-based bulky counterions against aggregation-caused quenching of dyes in fluorescent polymeric nanoparticles

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Aggregate 2022年第1期3卷 168-177页

作者： Caterina Severi Satu Lahtinen jaana Rosenberg Andreas Reisch Tero Soukka Andrey S.Klymchenko Laboratoire de Biophotonique et Pathologies Faculte de PharmacieUMR 7021 CNRSUniversite de StrasbourgCedexIllkirchFrance Department of Biotechnology University of TurkuTurkuFinland

Dye-loaded polymeric nanoparticles(NPs)are promising bioimaging agents because of their available surface chemistry,high brightness,and tunable optical ***,high dye loadings can cause the aggregation-caused quenching(ACQ)of the encapsulated ***,we proposed to mitigate the ACQ inside polymeric NPs by insulating cationic dyes with bulky hydrophobic *** order to implement new functionalities into dye-loaded NPs,here,we extend the concept of bulky counterions to anionic lanthanide-based *** show that by employing Gd-based counterions with octadecyl rhodamine B loaded NPs at 30 wt% versus polymer,the fluorescence quantum yield can be increased to 10-fold(to 0.34).Moreover,Gd-anion provides NPs with enhanced contrast in electron microscopy.A combination of a luminescent Eu-based counterion with a far-red to near-infrared cyanine 5 dye(DiD)yields Forster resonance energy transfer NPs,where the UV-excited Eu-based counterion transfers energy to DiD,generating delayed fluorescence and large stokes shift of -340 *** studies reveal low cytotoxicity of NPs and their capacity to internalize without detectable dye leakage,in contrast to leaky NPs with small *** findings show that the aggregation behavior of cationic dyes in the polymeric NPs can be controlled by bulky lanthanide anions,which will help in developing bright luminescent multifunctional nanomaterials.

关键词： aggregation-caused quenching dye-loaded polymeric nanoparticles fluorescence microscopy

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基于反向方法的船体冰载荷研究（英文）

船舶力学 2016年第12期20卷 1604-1618页

作者：刘瀛昊 SUOMINEN Mikko KUJALA pentti 哈尔滨工程大学船舶工程学院哈尔滨150001 阿尔托大学应用力学系船舶技术实验室芬兰15300

船舶碰撞海冰引起的冰载荷分布是十分复杂的。文章选取Thikhonov正则化这一反向方法,根据极地科考补给船S.A Agulhas II号于2013-2014年间南极航行时实测的数据,分析得到了船体艉肩部的冰载荷。通过应用三种独立的冰载荷离散方式来模拟... 详细信息

船舶碰撞海冰引起的冰载荷分布是十分复杂的。文章选取Thikhonov正则化这一反向方法,根据极地科考补给船S.A Agulhas II号于2013-2014年间南极航行时实测的数据,分析得到了船体艉肩部的冰载荷。通过应用三种独立的冰载荷离散方式来模拟海冰的自然特性,在有限元中得到模型的影响矩阵,并应用Matlab对Thikhonov正则化方程进行了优化。研究结果表明,反向方法可以克服数据处理过程中的不适定性,并计算得到船体冰载荷。

关键词：冰载荷有限元方法(FEM) Thikhonov正则化载荷离散反向方法

Effect of weld microstructure on brittle fracture initiation in the thermallyaged boiling water reactor pressure vessel head weld metal

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International Journal of Minerals,Metallurgy and Materials 2021年第5期28卷 867-876页

作者： Noora Hytönen Zai-qing Que pentti Arffman Jari Lydman Pekka Nevasmaa Ulla Ehrnstén Pål Efsing Nuclear Reactor Materials VTT Technical Research Centre of Finland Ltd.Kivimiehentie 3P.O.Box 1000FI-02044 VTTFinland Department of Solid Mechanics Royal Institute of Technology(KTH)SE-10044 StockholmSweden

Effects of the weld microstructure and inclusions on brittle fracture initiation are investigated in a thermally aged ferritic high-nickel weld of a reactor pressure vessel head from a decommissioned nuclear power ***-welded and reheated regions mainly consist of acicular and polygonal ferrite,*** examination of Charpy V-notch impact toughness specimens reveals large inclusions(0.5-2.5μm)at the brittle fracture primary initiation *** impact energies were measured for the specimens in which brittle fracture was initiated from a small inclusion or an inclusion away from the *** density,geometry,and chemical composition of the primary initiation inclusions were investigated.A brittle fracture crack initiates as a microcrack either within the multiphase oxide inclusions or from the debonded interfaces between the uncracked inclusions and weld metal *** fracture sites can be determined in all the specimens tested in the lower part of the transition curve at and below the 41-J reference impact toughness energy but not above the mentioned value because of the changes in the fracture mechanism and resulting changes in the fracture appearance.

关键词： reactor pressure vessel brittle fracture weld microstructure thermal aging

Reducing the loss of genetic diversity associated with assisted colonization-like introductions of animals

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Current Zoology 2015年第5期61卷 827-834页

作者： jaana KEKKONEN Jon E. BROMMER Department of Biosciences University of Helsinki Helsinki Finland Department of Biology University of Turku Turku Finland

Translocations, especially assisted colonizations, of animals are increasingly used as a conservation management tool. In many cases, however, limited funding and other logistic challenges limit the number of individuals available for transloeation. In conservation genetics, small populations are predicted to rapidly lose genetic diversity which can deteriorate population survival. Thus, how worried should we be about the loss of genetic diversity when introducing small, isolated populations？ Historical species introductions provide a means to assess these issues. Here we review 13 studies of ＂assisted colonization-like＂ introductions of animals, where only a small known number of founders established an isolated population without secondary contact to the source population. We test which factors could be important in retaining genetic diversity in these cases. In many cases, loss in heterozygosity （-12.1%） was detected, and more seriously the loss in allelic richness （-27.8 %）. Number of founders seemed to have an effect but it also indicated that high population growth rate could help to retain genetic diversity, i.e. future management actions could be effective even with a limited number of founders if population growth would be enhanced. On the contrary, translocated organisms with longer generation times did not seem to retain more genetic diversity. We advocate that, where possible, future studies on translocated animals should report the loss of genetic diversity （both heterozygosity and allelic richness）, which is essential for meta-analyses like this one for deepening our understanding of the genetic consequences of assisted colonization, and justifying management decisions [Current Zoology 61 （5）： 827-834, 2015].

关键词： Introduced species Loss of genetic diversity Number of founders Conservation management Population growth rate Generation time