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Optimization of the Mean Radius Flow Path of a Multi-Stage Steam Turbine with Evolution Algorithms

Journal of Thermal Science 2011年第4期20卷 318-323页

作者： Jukka Huttunen Jaakko Larjola Teemu Turunen-Saaresti Jari Backman Savonia Power ljytie 678710 VarkausFinlandjukka Lappeenranta University of technology P.O.Box 2053851 LappeenrantaFinland

A prototype model of the mean radius flow path of a four-stage, high speed 1 MWe axial steam turbine was optimized by using evolution algorithms, DE （differential evolution） algorithm in this case. Also the cost-benefits of the optimization were inspected. The optimization was successfully performed but the accuracy of the optimization was slightly less than hoped when compared to the control modeling executed with the CFD （computational fluid dynamics）. The mentioned inaccuracy could have been hardly avoided because of problems with an initial presumption involving semi-empiric calculations and of the uncertainty concerning the absolute areas of qualification of the functions. This kind of algebraic modeling was essential for the success of the optimization because e.g. CFD-calculation could not have been done on each step of the optimization. During the optimization some problems occurred with the adequacy of the computer capacity and with finding a suitable solution that would keep the algorithms within mathematically allowable boundaries but would not restrict the progress of the opti- mization too much. The rest of the problems were due to the novelty of the application and problems with pre- ciseness when handling the areas of qualification of the functions. Although the accuracy of the optimization re- suits was not exactly in accordance with the objective, they did have a favorable effect on the designing of the turbine. The optimization executed with the help of the DE-algorithm got at least about 3.5 % more power out of the turbine which means about 150 000 ε cost-benefit per turbine in the form of additional electricity capacity.

关键词： steam turbine evolution algorithm optimization mean radius flow path semi-empirical loss correlations

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High-fat-induced intestinal permeability dysfunction associated with altered fecal bile acids

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World Journal of Gastroenterology 2012年第9期18卷 923-929页

作者： Lotta K Stenman Reetta Holma Riitta Korpela Institute of Biomedicine PharmacologyUniversity of Helsinki

AIM： To investigate whether high-fat-feeding is associ- ated with increased intestinal permeability via altera- tions in bile acid metabolism.METHODS： Male C57BI/6J mice were fed on a high-fat （n = 26） or low-fat diet （n = 24） for 15 wk. Intestinal permeability was measured from duodenum, jejunum, ileum and colon in an Ussing chamber system using 4 kDa FITC-labeled dextran as an indicator. Fecal bile ac- ids were analyzed with gas chromatography. Segments of jejunum and colon were analyzed for the expression of farnesoid X receptor （FXR） and tumor necrosis factor

关键词： Bile acids Bile salts Diet-induced obesity Farnesoid X-activated receptor Intestinal permeability Ursodeoxycholic acid

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Are globoseries glycosphingolipids SSEA-3 and-4 markers for stem cells derived from human umbilical cord blood?

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Journal of Molecular Cell Biology 2011年第2期3卷 99-107页

作者： Heli Suila Virve Pitka¨nen Tia Hirvonen Annamari Heiskanen Heidi Anderson Anita Laitinen Suvi Natunen Halina Miller-Podraza Tero Satomaa Jari Natunen Saara Laitinen Leena Valmu Research and Development Finnish Red Cross Blood ServiceR&DKivihaantie 7FIN-00310 HelsinkiFinland Glykos Finland Ltd Viikinkaari 600790 HelsinkiFinland Department of Medical Chemistry and Cell Biology Institute of BiomedicineGothenburg UniversitP.O.Box 440SE 40530 GothenburgSweden

Umbilical cord blood(UCB)is an efficient and valuable source of hematopoietic stem cells(HSCs)for *** addition to HSCs it harbours low amounts of mesenchymal stem cells(MSCs).No single marker to identify cord blood-derived stem cells,or to indicate their multipotent phenotype,has been characterized so ***-3 and-4 are cell surface globoseries glycosphingolipid epitopes that are commonly used as markers for human embryonic stem cells,where SSEA-3 rapidly disappears when the cells start to *** SSEA-3 and-4 have also been observed in *** there is an ongoing discussion and variation of stem-cell markers between laboratories,we have now comprehensively characterized the expression of these epitopes in both the multipotent stem-cell types derived from *** have performed complementary analysis using gene expression analysis,mass spectrometry and immunochemical methods,including both flow cytometry and immunofluoresence ***-4,but not SSEA-3,was expressed on MSCs but absent from *** findings indicate that SSEA-3 and/or-4 may not be optimal markers for multipotency in the case of stem cells derived from cord blood,as their expression may be altered by cell-culture conditions.

关键词： umbilical cord blood hematopoietic stem cells mesenchymal stem cells SSEA-3 SSEA-4

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Effect of probiotic Lactobacillus rhamnosus GG intervention on global serum lipidomic profiles in healthy adults

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World Journal of Gastroenterology 2008年第20期14卷 3188-3194页

作者： Riina A Kekkonen Marko Sysi-Aho Tuulikki Seppnen-Laakso Ilkka Julkunen Heikki Vapaatalo Matej Orei Riitta Korpela University of Helsinki Institute of Biomedicine Pharmacology University of Helsinki VTT Technical Research Centre of Finland National Public Health Institute Department of Viral Diseases and Immunology

AIM: To investigate the effect of three weeks’ intervention with a probiotic Lactobacillus rhamnosus GG (LGG) bacteria on global serum lipidomic profiles and evaluate whether the changes in inflammatory variables (CRP, TNF-α and IL-6) are reflected in the global lipidomic profiles of healthy adults. METHODS: We performed UPLC/MS-based global lipidomic platform analysis of serum samples (n = 26) in a substudy of a randomised, double-blind, placebo- controlled 3-wk clinical intervention trial investigating the immunomodulatory effects of probiotics in healthy adults. RESULTS: A total of 407 lipids were identified, corresponding to 13 different lipid classes. Serum samples showed decreases in the levels of lysophosphatidylcholines (LysoGPCho), sphingomyelins (SM) and several glycerophosphatidylcholines (GPCho), while triacylglycerols (TAG) were mainly increased in the probiotic LGG group during the intervention. Among the inflammatory variables, IL-6 was moderatelyassociated by changes in global lipidomic profiles, with the top-ranked lipid associated with IL-6 being the proinflammatory LysoGPCho (20:4). There was a weak association between the lipidomic profiles and the two other inflammatory markers, TNF-α and CRP. CONCLUSION: This was the first study to investigate the effects of probiotic intervention on global lipidomic profiles in humans. There are indications that probiotic LGG intervention may lead to changes in serum global lipid profiles, as reflected in decreased GPCho, LysoGPCho and SM as well as mainly increased TAG.

关键词： Probiotic Lactobacillus rhamnosus GG Lipidomic Inflammatory mediators Healthy adults

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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

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Feasibility of Pulse Combustion in Micro Gas Turbines

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Journal of Thermal Science 2012年第5期21卷 466-473页

作者： Juha Honkatukia Esa Saari Timo Knuuttila Jaakko Larjola Jari Backman Lappeenranta University of technology P.O. Box 2053851 Lappeenranta Finland T-Turbine Oy Rakentajainkuja 4 B02330 Espoo Finland

In gas turbines, a fast decrease of efficiency appears when the output decreases; the efficiency of a large gas tur-bine （20...30 MW） is in the order of 40 %, the efficiency of a 30 kW gas turbine with a recuperator is in the order of 25 %, but the efficiency of a very small gas turbine （2...6 kW） in the order of 4...6 % （or 8... 12 % with an op- timal recuperator）. This is mainly a result of the efficiency decrease in kinetic compressors, due to the Reynolds number effect. Losses in decelerating flow in a flow passage are sensitive to the Reynolds number effects. In con- trary to the compression, the efficiency of expansion in turbines is not so sensitive to the Reynolds number; very small turbines are made with rather good efficiency because the flow acceleration stabilizes the boundary layer. This study presents a system where the kinetic compressor of a gas turbine is replaced with a pulse combustor. The combustor is filled with a combustible gas mixture, ignited, and the generated high pressure gas is expanded in the turbine. The process is repeated frequently, thus producing a pulsating flow to the turbine; or almost a uni- form flow, if several parallel combustors are used and triggered a/ternately in a proper way. Almost all the com- pression work is made by the temperature increase from the combustion. This gas turbine type is investigated theoretically and its combustor also experimentally with the conclusion that in a 2 kW power size, the pulse flow gas turbine is not as attractive as expected due to the big size and weight of parallel combustors and due to the ef- ficiency being in the order of 8 % to 10 %. However, in special applications having a very low power demand, below 1000 W, this solution has better properties when compared to the conventional gas turbine and it could be worth of a more detailed investigation.

关键词： Gas turbine pulse combustion micro size low Reynolds number

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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

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Elevated pro-inflammatory and lipotoxic mucosal lipids characterise irritable bowel syndrome

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World Journal of Gastroenterology 2009年第48期15卷 6068-6074页

作者： Kajsa Kajander Eveliina Myllyluoma Sinikka Kyrnpalo Martin Rasmussen Pentti Sipponen Ismo Mattila Tuulikki Seppnen-Laakso Heikki Vapaatalo Matej Orei Riitta Korpela Institute of Biomedicine PharmacologyUniversity of Helsinki Valio Ltd Research Centre Tampere Health Centre and Department of Medicine Tampere City Hospital Department of Pathology Jorvi HospitalHelsinki University Central Hospital VTT Technical Research Centre of Finland Foundation for Nutrition Research

AIM： To investigate the pathophysiology of irritable bowel syndrome （IBS） by comparing the global mucosal metabolic profiles of IBS patients with those of healthy controls. METHODS： Fifteen IBS patients fulfilling the Rome II criteria, and nine healthy volunteers were included in the study. A combined lipidomics （UPLC/MS） and metabolomics （GC × GC-TOF） approach was used to achieve global metabolic profiles of mucosal biopsies from the ascending colon. RESULTS： Overall, lipid levels were elevated in patients with IBS. The most significant upregulation was seen for pro-inflammatory lysophosphatidylcholines. Other lipid groups that were significantly upregulated in IBS patients were lipotoxic ceramides, glycosphingolipids, and di-and triacylglycerols. Among the meo tabolites, the cyclic ester 2（3H）-furanone was almost 14-fold upregulated in IBS patients compared to healthy subjects （P = 0.03）. CONCLUSION： IBS mucosa is characterised by a distinct pro-inflammatory and lipotoxic metabolic profile. Especially, there was an increase in several lipid species such as lysophospholipids and ceramides.

关键词： Functional gastrointestinal diseases Irritable bowel syndrome Histopathology

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Association of symptoms with gastrointestinal microbiota in irritable bowel syndrome

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World Journal of Gastroenterology 2010年第36期16卷 4532-4540页

作者： Erja Malinen Lotta Krogius-Kurikka Janne Nikkil Airi Palva Anna Lyra Anne Jskelinen Teemu Rinttil Terttu Vilpponen-Salmela Atte Johannes von Wright Department of Veterinary Biosciences Faculty of Veterinary MedicineUniversity of Helsinki00014 HelsinkiFinland Danisco Sweeteners Health and Nutrition02460 KantvikFinland Department of Clinical Nutrition Institute of Public Health and Clinical NutritionFaculty of Health SciencesUniversity of Eastern Finland70211 KuopioFinland Alimetrics Ltd. Koskelontie 19 B02920 EspooFinland Kuopio Harjula Hospital 70101 KuopioFinland Department of Biosciences University of Eastern Finland70211 KuopioFinland

AIM:To investigate the correlations between selfreported symptoms of irritable bowel syndrome(IBS) and the gastrointestinal(GI) microbiota ***:Fecal samples were collected from a total of 44 subjects diagnosed with *** symptoms were monitored with a validated inflammatory bowel disease questionnaire adjusted for IBS *** quantitative real-time polymerase chain reaction assays were applied to evaluate the GI microbiota *** and GI bacterial genera(Bifidobacterium,Lactobacillus and Veillonella),groups(Clostridium coccoides/Eubacterium rectale,Desulfovibrio desulfuricans) and distinct bacterial phylotypes [closest 16S rDNA sequence resemblance to species Bifidobacterium catenulatum,Clostridium cocleatum,Collinsella aerofaciens(***),Coprococcus eutactus(***),Ruminococcus torques and Streptococcus bovis ] with a suspected association with IBS were *** between quantities or presence/absence data of selected bacterial groups or phylotypes and various IBSrelated symptoms were ***:Associations were observed between subjects' self-reported symptoms and the presence or quantities of certain GI bacteria.A Ruminococcus torques(***)-like(94% similarity in 16S rRNA gene sequence) phylotype was associated with severity of bowel ***,among IBS subjects with *** 94% detected,the amounts of *** 88%,***-like and *** 97% phylotypes were significantly *** observations were also made concerning the effect of a subject's weight on GI microbiota with regard to *** like phylotype,Bifidobacterium *** Lactobacillus ***:Bacteria seemingly affecting the symptom scores are unlikely to be the underlying cause or cure of IBS,but they may serve as biomarkers of the condition.

关键词： Irritable bowel syndrome Self-reported symptoms Gastrointestinal microbiota Quantitative realtime polymerase chain reaction

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Single-walled carbon nanotube networks for ethanol vapor sensing applications

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Nano Research 2013年第2期6卷 77-86页

作者： Ilya V. Anoshkint Albert G. Nasibulin Prasantha R. Mudimela Maoshuai He Vladimir Ermolov Eskol. Kauppinen Department of Applied Physics Aalto University School of Science P.O. Box 15100 Espoo F1-00076 AALTO Finland Research Center in Physics of Matter and Radiation (PMR) University of Namur (FUNDP) rue de Bruxelles 61 B-5000 Namur Belgium Department of Biotechnology and Chemical technology Aalto University School of Chemical Technology P.O. Box 16100 F1-00076 Aalto Finland Nokia Research Center Helsinki Finland

Networks of pristine high quality single walled carbon nanotubes （SWNTs）, the SWNTs after Ar-plasma treatment （from 2 to 12 rain） and carbon nanobuds （CNBs） have been tested for ethanol vapor sensing. It was found that the pristine high quality SWNTs do not exhibit any ethanol sensitivity, while the introduction of defects in the tubes results in the appearance of the ethanol sensitivity. The CNB network showed ethanol sensitivity without plasma treatment. Both CNB and low defect （after 3 min treatment） SWNT networks exhibit significant drift in the resistance baseline, while heavily plasma-treated （9 min） SWNTs exhibited high ethanol vapor sensitivity without the baseline change. The mechanisms of the ethanol sensitivity and stability after the plasma irradiation are attributed to the formation of sensitive dangling bonds in the SWNTs and formation of defect channels facilitating access of the ethanol vapor to all parts of the bundled nanotubes.

关键词： single walled carbonnanotubes carbon nanobuds At-plasma ethanol vapor sensor

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