119 resultados para OMXH Small Cap
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Nimeketiedot nimiönkehyksissä
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The application of computational fluid dynamics (CFD) and finite element analysis (FEA) has been growing rapidly in the various fields of science and technology. One of the areas of interest is in biomedical engineering. The altered hemodynamics inside the blood vessels plays a key role in the development of the arterial disease called atherosclerosis, which is the major cause of human death worldwide. Atherosclerosis is often treated with the stenting procedure to restore the normal blood flow. A stent is a tubular, flexible structure, usually made of metals, which is driven and expanded in the blocked arteries. Despite the success rate of the stenting procedure, it is often associated with the restenosis (re-narrowing of the artery) process. The presence of non-biological device in the artery causes inflammation or re-growth of atherosclerotic lesions in the treated vessels. Several factors including the design of stents, type of stent expansion, expansion pressure, morphology and composition of vessel wall influence the restenosis process. Therefore, the role of computational studies is crucial in the investigation and optimisation of the factors that influence post-stenting complications. This thesis focuses on the stent-vessel wall interactions followed by the blood flow in the post-stenting stage of stenosed human coronary artery. Hemodynamic and mechanical stresses were analysed in three separate stent-plaque-artery models. Plaque was modeled as a multi-layer (fibrous cap (FC), necrotic core (NC), and fibrosis (F)) and the arterial wall as a single layer domain. CFD/FEA simulations were performed using commercial software packages in several models mimicking the various stages and morphologies of atherosclerosis. The tissue prolapse (TP) of stented vessel wall, the distribution of von Mises stress (VMS) inside various layers of vessel wall, and the wall shear stress (WSS) along the luminal surface of the deformed vessel wall were measured and evaluated. The results revealed the role of the stenosis size, thickness of each layer of atherosclerotic wall, thickness of stent strut, pressure applied for stenosis expansion, and the flow condition in the distribution of stresses. The thicknesses of FC, and NC and the total thickness of plaque are critical in controlling the stresses inside the tissue. A small change in morphology of artery wall can significantly affect the distribution of stresses. In particular, FC is the most sensitive layer to TP and stresses, which could determine plaque’s vulnerability to rupture. The WSS is highly influenced by the deflection of artery, which in turn is dependent on the structural composition of arterial wall layers. Together with the stenosis size, their roles could play a decisive role in controlling the low values of WSS (<0.5 Pa) prone to restenosis. Moreover, the time dependent flow altered the percentage of luminal area with WSS values less than 0.5 Pa at different time instants. The non- Newtonian viscosity model of the blood properties significantly affects the prediction of WSS magnitude. The outcomes of this investigation will help to better understand the roles of the individual layers of atherosclerotic vessels and their risk to provoke restenosis at the post-stenting stage. As a consequence, the implementation of such an approach to assess the post-stented stresses will assist the engineers and clinicians in optimizing the stenting techniques to minimize the occurrence of restenosis.
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Lisäkartta: Plan et vue des terres du Cap de la Circoncision situé à 54 degrées de lat. méridiole et environ à 28 deg. 30 min. de longitude = Plan et gezigt van de landen van de Caap der Besnydenis gelegen op 54 gr. zuider br. en omtrent op 28 gr. 30 min. - Eteläisen pallonpuoliskon halkaisija 44,6 cm
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Kartta kuuluu A. E. Nordenskiöldin kokoelmaan
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Demand for the use of energy systems, entailing high efficiency as well as availability to harness renewable energy sources, is a key issue in order to tackling the threat of global warming and saving natural resources. Organic Rankine cycle (ORC) technology has been identified as one of the most promising technologies in recovering low-grade heat sources and in harnessing renewable energy sources that cannot be efficiently utilized by means of more conventional power systems. The ORC is based on the working principle of Rankine process, but an organic working fluid is adopted in the cycle instead of steam. This thesis presents numerical and experimental results of the study on the design of small-scale ORCs. Two main applications were selected for the thesis: waste heat re- covery from small-scale diesel engines concentrating on the utilization of the exhaust gas heat and waste heat recovery in large industrial-scale engine power plants considering the utilization of both the high and low temperature heat sources. The main objective of this work was to identify suitable working fluid candidates and to study the process and turbine design methods that can be applied when power plants based on the use of non-conventional working fluids are considered. The computational work included the use of thermodynamic analysis methods and turbine design methods that were based on the use of highly accurate fluid properties. In addition, the design and loss mechanisms in supersonic ORC turbines were studied by means of computational fluid dynamics. The results indicated that the design of ORC is highly influenced by the selection of the working fluid and cycle operational conditions. The results for the turbine designs in- dicated that the working fluid selection should not be based only on the thermodynamic analysis, but requires also considerations on the turbine design. The turbines tend to be fast rotating, entailing small blade heights at the turbine rotor inlet and highly supersonic flow in the turbine flow passages, especially when power systems with low power outputs are designed. The results indicated that the ORC is a potential solution in utilizing waste heat streams both at high and low temperatures and both in micro and larger scale appli- cations.
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Tämän tutkielman tarkoitus on selvittää, miten epäsymmetrinen sodankäynti Irakissa vuosina 2003–2008 vaikutti Yhdysvaltain armeijaan ja merijalkaväkeen. Päätutkimuskysymykseen vas-tataan selvittämällä historian kokemuksien vaikutus siihen miten Irakin sotaan valmistauduttiin. Tarkoituksena on myös selvittää miten epäsymmetrinen sota ilmeni vuosien kuluessa ja miten amerikkalaiset kehittivät varusteita, koulutusta, organisaatioita ja doktriiniaan sodan kuluessa. Lähdeaineistona on käytetty englanninkielistä kirjallisuutta. Suurin osa aineistosta on operaati-oon osallistuneiden sotilaiden ja siviilien kirjoittamia. He ovat kirjoittaneet joko omien koke-muksien pohjalta tai sitten teoksissa on haastateltu tapahtumia todistaneita avainhenkilöitä. Li-säksi on käytetty sotilasammatillisissa lehdissä julkaistuja artikkeleita, asevoimien ohjesääntöjä ja eri puolustushallinnon sekä riippumattomien tutkimuslaitoksien tekemiä raportteja. Opinnäyt-teiden osuus on vähäinen ja haastatteluja ei ole käytetty. Tutkimusmenetelmä on aineistoanalyy-siin perustuva kirjallisuustutkimus. Työssä korostuu lähdekritiikki ja lähteiden vertailu, koska ajoittain lähteissä esitetyt tiedot ovat kirjoittajien omia näkemyksiä historiallisista tapahtumista. Vuonna 2003 alkanut Irakin sota kehittyi vuosia kestäneeksi taisteluksi epäsymmetrisesti toimi-vaa vihollista vastaan. Irakin sodan kynnyksellä operaation suunnittelussa ei huomioitu hyökkä-yksen jälkeistä vakauttamisvaihetta riittävällä tarkkuudella. Seurauksena oli se että Irakin ajau-tumista sekasortoon Baghdadin valtauksen jälkeen ei voitu estää. Liittouman päätös lakkauttaa Irakin omat turvallisuuskoneistot vaikeutti tilannetta entisestään. Vuoden 2003 lopulla Irak oli ajautumassa etnisten ja uskonnollisten ristiriitojen vaikuttamaan kumoukselliseen sotaan. Seu-raavat vuodet Yhdysvallat pyrki viholliskeskeisellä strategialla kukistamaan epäsymmetrisesti toimivat kumoukselliset taistelijat. Keskeisinä tutkielman havaintoina on, että Yhdysvalloilla on paljon kokemusta epäsymmetri-sestä sodankäynnistä. Historian kokemuksista johtuvien asenteiden ja vuonna 2003 vaikuttaneen poliittisen ilmapiirin vuoksi Irakin sodan miehitysvaihetta ei suunniteltu kunnolla. Yhtenäisen strategian puute aiheutti ongelmia sodan alkuvuosina. Tänäkin aikana osa joukoista toteutti on-nistuneesti vastakumouksellisen sodan operaatioita, jotka vaikuttivat uuden doktriinin syntyyn. Doktriinin avaintekijä oli uusi ohjesääntö FM 3-24, jonka opit olivat keskeisessä asemassa vuonna 2007 alkaneissa operaatioissa. Näiden operaatioiden menestyksen taustalla oli monia tekijöitä, mutta myös amerikkalaisten uudenlainen ymmärrys siitä miten taistella epäsymmetri-sesti toimivaa vihollista vastaan. Sotakokemukset synnyttivät uusia varusteita, koulutusta ja organisaatiomuutoksia. Suurin vaikutus on kuitenkin siinä, miten vuoteen 2008 mennessä epä-tavanomaisen sodankäynnin merkitys asevoimien tehtävissä oli noussut aiempaa tärkeämmäksi.
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Mitosis is under the stringent quality control of the spindle assembly checkpoint (SAC). However, in cancer cells this control can fail, leading to excessive cellular proliferation and ultimately to the formation of a tumor. Novel cancer cell selective therapies are needed to stop the uncontrolled cell proliferation and tumor growth. The aim of the research presented in this thesis was to identify microRNAs (miRNAs) that could play a role in cancer cell proliferation as well as low molecular weight (LMW) compounds that could interfere with cell division. The findings could be used to develop better cancer diagnostics and therapies in the future. First, a high-throughput screen (HTS) was performed to identify LMW compounds that possess a similar chemical interaction field as rigosertib, an anti-cancer compound undergoing clinical trials. A compound termed Centmitor-1 was discovered that phenocopied the cellular impact of rigosertib by affecting the microtubule dynamics. Next, another HTS aimed at identifying compounds that would target the Hec1 protein, which mediates the interaction between spindle microtubules and chromosomes. Perturbation of this connection should prevent cell division and induce cell death. A compound termed VTT-006 was discovered that abrogated mitosis in several cell line models and exhibited binding to Hec1 in vitro. Lastly, using a cell-based HTS two miRNAs were identified that affected cancer cell proliferation via Aurora B kinase, which is an important mitotic regulator. MiR-378a-5p was found to indirectly suppress the production of the kinase whereas let-7b showed direct binding to the 3’UTR of Aurora B mRNA and repressed its translation. The miRNA-mediated perturbation of Aurora B induced defects in mitosis leading to abnormal chromosome segregation and induction of aneuploidy. The results of this thesis provide new information on miRNA signaling in cancer, which could be utilized for diagnostic purposes. Moreover, the thesis introduces two small compounds that may benefit future drug research.
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This thesis presents an analysis of recently enacted Russian renewable energy policy based on capacity mechanism. Considering its novelty and poor coverage by academic literature, the aim of the thesis is to analyze capacity mechanism influence on investors’ decision-making process. The current research introduces a number of approaches to investment analysis. Firstly, classical financial model was built with Microsoft Excel® and crisp efficiency indicators such as net present value were determined. Secondly, sensitivity analysis was performed to understand different factors influence on project profitability. Thirdly, Datar-Mathews method was applied that by means of Monte Carlo simulation realized with Matlab Simulink®, disclosed all possible outcomes of investment project and enabled real option thinking. Fourthly, previous analysis was duplicated by fuzzy pay-off method with Microsoft Excel®. Finally, decision-making process under capacity mechanism was illustrated with decision tree. Capacity remuneration paid within 15 years is calculated individually for each RE project as variable annuity that guarantees a particular return on investment adjusted on changes in national interest rates. Analysis results indicate that capacity mechanism creates a real option to invest in renewable energy project by ensuring project profitability regardless of market conditions if project-internal factors are managed properly. The latter includes keeping capital expenditures within set limits, production performance higher than 75% of target indicators, and fulfilling localization requirement, implying producing equipment and services within the country. Occurrence of real option shapes decision-making process in the following way. Initially, investor should define appropriate location for a planned power plant where high production performance can be achieved, and lock in this location in case of competition. After, investor should wait until capital cost limit and localization requirement can be met, after that decision to invest can be made without any risk to project profitability. With respect to technology kind, investment into solar PV power plant is more attractive than into wind or small hydro power, since it has higher weighted net present value and lower standard deviation. However, it does not change decision-making strategy that remains the same for each technology type. Fuzzy pay-method proved its ability to disclose the same patterns of information as Monte Carlo simulation. Being effective in investment analysis under uncertainty and easy in use, it can be recommended as sufficient analytical tool to investors and researchers. Apart from described results, this thesis contributes to the academic literature by detailed description of capacity price calculation for renewable energy that was not available in English before. With respect to methodology novelty, such advanced approaches as Datar-Mathews method and fuzzy pay-off method are applied on the top of investment profitability model that incorporates capacity remuneration calculation as well. Comparison of effects of two different RE supporting schemes, namely Russian capacity mechanism and feed-in premium, contributes to policy comparative studies and exhibits useful inferences for researchers and policymakers. Limitations of this research are simplification of assumptions to country-average level that restricts our ability to analyze renewable energy investment region wise and existing limitation of the studying policy to the wholesale power market that leaves retail markets and remote areas without our attention, taking away medium and small investment into renewable energy from the research focus. Elimination of these limitations would allow creating the full picture of Russian renewable energy investment profile.
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A direct-driven permanent magnet synchronous machine for a small urban use electric vehicle is presented. The measured performance of the machine at the test bench as well as the performance over the modified New European Drive Cycle will be given. The effect of optimal current components, maximizing the efficiency and taking into account the iron loss, is compared with the simple id=0 – control. The machine currents and losses during the drive cycle are calculated and compared with each other.
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The main objective of the study was to define the methodology for assessing the limits for application island grids instead of interconnecting with existing grid infrastructure. The model for simulation of grid extension distance and levelised cost of electricity has been developed and validated by the case study in Finland. Thereafter, sensitivities of the application limits were examined with the respect to operational environment, load conditions, supply security and geographical location. Finally, recommendations for the small-scale rural electrification projects in the market economy environment have been proposed.
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Invokaatio: Syn tō theō trismegistō.
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Arkit: 1 arkintunnukseton lehti, A-B4 C2. - S. [2] tyhjä.
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Arkit: 1 arkintunnukseton lehti, D4 E2. - S. [2] tyhjä.