998 resultados para calcium signals integration


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The objective of this Master’s Thesis is to find out best practices for IT service management integration. Integration in this context means process integration between an IT organization and an integration partner. For observing the objective, two different perspectives are assigned: process and technology. The thesis consists of theory, framework, implementation, and analysis parts. The first part introduces common methodology of IT service management and enterprise integration. The second part presents an integration framework for ITSM integration. The third part illustrates how the framework is used and the last part analyses the framework. The major results of this thesis were the framework architecture, the framework tools, the implementation model, the testing model, and the deployment model for ITSM integration. As a fundamental best practice, the framework contained a four-division structure between architecture, process, data, and technology. This architecture provides a baseline for ITSM integration design, implementation and testing.

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Frontier and Emerging economies have implemented policies with the objective of liberalizing their equity markets. Equity market liberalization opens the domestic equity market to foreign investors and as well paves the way for domestic investors to invest in foreign equity securities. Among other things, equity market liberalization results in diversification benefits. Moreover, equity market liberalization leads to low cost of equity capital resulting from the lower rate of return by investors. Additionally, foreign and local investors share any potential risks. Liberalized equity markets also become liquid considering that there are more investors to trade. Equity market liberalization results in financial integration which explains the movement of two markets. In crisis period, increased volatility and co-movement between two markets may result in what is termed contagion effects. In Africa, major moves toward financial liberalization generally started in the late 1980s with South Africa as the pioneer. Over the years, researchers have studied the impact of financial liberalization on Africa’s economic development with diverse results; some being positive, others negative and still others being mixed. The objective of this study is to establish whether African stock-markets are integrated into the United States (US) and World market. Furthermore, the study helps to see if there are international linkages between the Africa, US and the world markets. A Bivariate- VAR- GARCH- BEKK model is employed in the study. In the study, the effect of thin trading is removed through series of econometric data purification. This is because thin trading, also known as non-trading or inconsistency of trading, is a main feature of African markets and may trigger inconsistency and biased results. The study confirmed the widely established results that the South Africa and Egypt stock markets are highly integrated with the US and World market. Interestingly, the study adds to knowledge in this research area by establishing the fact that Kenya is very integrated with the US and World markets and that it receives and exports past innovations as well as shocks to and from the US and World market.

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This thesis presents a one-dimensional, semi-empirical dynamic model for the simulation and analysis of a calcium looping process for post-combustion CO2 capture. Reduction of greenhouse emissions from fossil fuel power production requires rapid actions including the development of efficient carbon capture and sequestration technologies. The development of new carbon capture technologies can be expedited by using modelling tools. Techno-economical evaluation of new capture processes can be done quickly and cost-effectively with computational models before building expensive pilot plants. Post-combustion calcium looping is a developing carbon capture process which utilizes fluidized bed technology with lime as a sorbent. The main objective of this work was to analyse the technological feasibility of the calcium looping process at different scales with a computational model. A one-dimensional dynamic model was applied to the calcium looping process, simulating the behaviour of the interconnected circulating fluidized bed reactors. The model incorporates fundamental mass and energy balance solvers to semi-empirical models describing solid behaviour in a circulating fluidized bed and chemical reactions occurring in the calcium loop. In addition, fluidized bed combustion, heat transfer and core-wall layer effects were modelled. The calcium looping model framework was successfully applied to a 30 kWth laboratory scale and a pilot scale unit 1.7 MWth and used to design a conceptual 250 MWth industrial scale unit. Valuable information was gathered from the behaviour of a small scale laboratory device. In addition, the interconnected behaviour of pilot plant reactors and the effect of solid fluidization on the thermal and carbon dioxide balances of the system were analysed. The scale-up study provided practical information on the thermal design of an industrial sized unit, selection of particle size and operability in different load scenarios.

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Torrefaction is one of the pretreatment technologies to enhance the fuel characteristics of biomass. The efficient and continuous operation of a torrefaction reactor, in the commercial scale, demands a secure biomass supply, in addition to adequate source of heat. Biorefinery plants or biomass-fuelled steam power plants have the potential to integrate with the torrefaction reactor to exchange heat and mass, using available infrastructure and energy sources. The technical feasibility of this integration is examined in this study. A new model for the torrefaction process is introduced and verified by the available experimental data. The torrefaction model is then integrated in different steam power plants to simulate possible mass and energy exchange between the reactor and the plants. The performance of the integrated plant is investigated for different configurations and the results are compared.

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Kandidaatintyössä esitellään eri teknologioita hiilidioksidin talteenottamiseksi. Teknologioista esitellään niiden toimintaperiaate, pääpiirteet, heikkoudet ja vahvuudet, sekä nykytila. Työssä käsiteltiin kuutta teknologiaa: hiilidioksidin erotus polton jälkeen, hiilidioksidin erotus ennen polttoa, hiilidioksidin erotus happipoltolla, kemikaalikiertopoltto, kalsiumkiertoprosessi ja yhdistetty kolmen reaktorin kalsium- ja kemikaali kiertopolttoprosessia. Polton jälkeinen hiilidioksidin talteenotto sopii hyvin käytössä olevien laitoksien muuntamiseen niin kuin happipolttokin, mutta erotus ja talteenotto ennen polttoa ei sovellu kun vain uusiin laitoksiin. Kolme viimeisintä käsiteltyä teknologiaa ovat nuoria, kypsymättömiä, niissä paljon etuja ja niiden voi olettaa kehittyvän hyviksi teknologioiksi.

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Changes in the activities of oxidative enzymes (indole acetic acid oxidase, peroxidase and catalase), endogenous hormones (gibberellic acid (GA3), indole acetic acid (IAA), abscisic acid (ABA) and cytokinins (AsZeatin), photosynthetic pigments (chlorophyll a, chlorophyll b and carotenoids), total carbohydrates, total soluble sugars, amino acid proline and vegetative growth parameters were used as indicators to explain the physiological role of the growth retardant prohexadione-calcium on Vicia faba seedlings 40 days after sowing under salinity stress for 30 days. The obtained results show that soaking faba bean seeds prior to sowing at different concentrations of prohexadione-calcium (0, 10, 20 and 30 ppm) significantly increased the activities of indole acetic acid oxidase (IAA-oxidase) and peroxidase enzymes, but decreased the catalase enzyme activity as compared with their respective control. Application of prohexadione-Ca caused markedly decreases in the endogenous contents of gibberellins and indole acetic acid (IAA) but increased the levels of natural growth inhibitor abscisic acid (ABA) and cytokinins in the shoots of faba bean seedlings. All the prohexadione-Ca concentrations increased the contents of amino acid proline, photosynthetic pigments (chlorophyll a, chlorophyll b and carotenoids), total carbohydrates and total soluble sugars in faba bean seedlings grown under salt stress. Application of prohexadione-Ca decreased significantly seedling height and shoot fresh weight but significantly increased shoot dry weight.

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Field trial was conducted with the aim of utilizing allelopathic crop residues to reduce the use of synthetic herbicides in broad bean (Vicia faba) fields. Sunflower residue at 600 and 1,400 g m-2 and Treflan (trifluralin) at 50, 75 and 100% of recommended dose were incorporated into the soil alone or in combination with each other. Untreated plots were maintained as a control. Herbicide application in plots amended with sunflower residue had the least total weed count and biomass, which was even better than herbicide used alone. Integration of recommended dose of Treflan with sunflower residue at 1,400 g m-² produced maximum (987.5 g m-2) aboveground biomass of broad bean, which was 74 and 36% higher than control and recommended herbicide dose applied alone, respectively. Combination of herbicide and sunflower residue appeared to better enhance pod number and yield per unit area than herbicide alone. Application of 50% dose of Treflan in plots amended with sunflower residue resulted in similar yield advantage as was noticed with 100% herbicide dose. Chromatographic analysis of residue-infested field soil indicated the presence of several phytotoxic compounds of phenolic nature. Periodic data revealed that maximum suppression in weed density and dry weight synchronized with peak values of phytotoxins observed 4 weeks after incorporation of sunflower residues. Integration of sunflower residues with lower herbicide rates can produce effective weed suppression without compromising yield as a feasible and environmentally sound approach in broad bean fields.

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Papperstillverkningen störs ofta av oönskade föreningar som kan bilda avsättningar på processytor, vilket i sin tur kan ge upphov till störningar i pappersproduktionen samt försämring av papperskvaliteten. Förutom avsättningar av vedharts är stenliknande avlagringar av svårlösliga salter vanliga. I vårt dagliga liv är kalkavlagringar i kaffe- och vattenkokare exempel på liknande problem. I massa- och pappersindustrin är en av de mest problematiska föreningarna kalciumoxalat; detta salt är nästan olösligt i vatten och avlagringarna är mycket svåra att avlägsna. Kalciumoxalat är också känt som en av orsakerna till njurstenar hos människor. Veden och speciellt barken innehåller alltid en viss mängd oxalat men en större källa är oxalsyra som bildas när massan bleks med oxiderande kemikalier, t.ex. väteperoxid. Kalciumoxalat bildas när oxalsyran reagerar med kalcium som kommer in i processen med råvattnet, veden eller olika tillsatsmedel. I denna avhandling undersöktes faktorer som påverkar bildningen av oxalsyra och utfällningen av kalciumoxalat, med hjälp av bleknings- och utfällningsexperiment. Forskningens fokus låg speciellt på olika sätt att förebygga uppkomsten av avlagringar vid tillverkning av trähaltigt papper. Resultaten i denna avhandling visar att bildningen av oxalsyra samt utfällning av kalciumoxalat kan påverkas genom processtekniska och våtändskemiska metoder. Noggrann avbarkning av veden, kontrollerade förhållanden under den alkaliska peroxidblekningen, noggrann hantering och kontroll av andra lösta och kolloidala substanser, samt utnyttjande av skräddarsydd kemi för kontroll av avlagringar är nyckelfaktorer. Resultaten kan utnyttjas då man planerar blekningssekvenser för olika massor samt för att lösa problem orsakade av kalciumoxalat. Forskningsmetoderna som användes i utfällningsstudierna samt för utvärdering av tillsatsmedel kan också utnyttjas inom andra områden, t.ex. bryggeri- och sockerindustrin, där kalciumoxalatproblem är vanligt förekommande. -------------------------------------------- Paperinvalmistusta häiritsevät usein erilaiset epäpuhtaudet, jotka kiinnittyvät prosessipinnoille ja haittaavat tuotantoa sekä paperin laatua. Puun pihkan lisäksi eräs yleinen ongelma on niukkaliukoisten suolojen aiheuttamat kivettymät. Kalkkisaostuma kahvinkeittimessä on esimerkki vastaavasta ongelmasta arkielämässä. Massa- ja paperiteollisuudessa yksi hankalimmista kivettymien muodostajista on kalsiumoksalaatti, koska se on lähes liukenematonta ja sen aiheuttamat saostumat ovat erittäin vaikeasti poistettavia. Kalsiumoksalaatti on yleisesti tunnettu myös munuaiskivien aiheuttajana ihmisillä. Puu ja varsinkin sen kuori sisältää aina jonkin verran oksalaattia, mutta suurempi lähde on kuitenkin oksaalihappo jota muodostuu valkaistaessa massaa hapettavilla kemikaaleilla, kuten vetyperoksidilla. Kalsiumoksalaattia syntyy kun veden, puun ja lisäaineiden mukana prosessiin tuleva kalsium reagoi oksalaatin kanssa. Tässä väitöskirjatyössä tutkittiin oksaalihapon muodostumiseen ja kalsiumoksalaatin saostumiseen vaikuttavia tekijöitä valkaisu- ja saostumiskokeiden avulla. Tutkimuksen painopiste oli saostumien ehkäisemisessä puupitoisten painopaperien valmistuksessa. Työssä saadut tulokset osoittavat että oksaalihapon muodostumiseen ja kalsiumoksalaatin saostumiseen voidaan vaikuttaa sekä prosessiteknisten että märänpään kemian keinojen avulla. Tehokas puun kuorinta, optimoidut olosuhteet peroksidivalkaisussa, muiden liuenneiden ja kolloidisten aineiden hallinta sekä räätälöidyn kemian hyödyntäminen kalsiumoksalaattisaostumien torjunnassa ovat keskeisissä rooleissa ongelmien välttämiseksi. Väitöskirjatyön tuloksia voidaan hyödyntää massan valkaisulinjoja suunniteltaessa sekä kalsiumoksalaatin aiheuttamien ongelmien ratkaisemisessa. Tutkimusmenetelmiä, joita käytettiin saostumiskokeissa ja eri lisäaineiden vaikutusten arvioinnissa, voidaan hyödyntää massa- ja paperiteollisuuden lisäksi myös muilla alueilla, kuten sokeri- ja panimoteollisuudessa, joissa ongelma on myös yleinen.

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Poster at Open Repositories 2014, Helsinki, Finland, June 9-13, 2014

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Presentation at Open Repositories 2014, Helsinki, Finland, June 9-13, 2014

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Poster at Open Repositories 2014, Helsinki, Finland, June 9-13, 2014

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The steel industry produces, besides steel, also solid mineral by-products or slags, while it emits large quantities of carbon dioxide (CO2). Slags consist of various silicates and oxides which are formed in chemical reactions between the iron ore and the fluxing agents during the high temperature processing at the steel plant. Currently, these materials are recycled in the ironmaking processes, used as aggregates in construction, or landfilled as waste. The utilization rate of the steel slags can be increased by selectively extracting components from the mineral matrix. As an example, aqueous solutions of ammonium salts such as ammonium acetate, chloride and nitrate extract calcium quite selectively already at ambient temperature and pressure conditions. After the residual solids have been separated from the solution, calcium carbonate can be precipitated by feeding a CO2 flow through the solution. Precipitated calcium carbonate (PCC) is used in different applications as a filler material. Its largest consumer is the papermaking industry, which utilizes PCC because it enhances the optical properties of paper at a relatively low cost. Traditionally, PCC is manufactured from limestone, which is first calcined to calcium oxide, then slaked with water to calcium hydroxide and finally carbonated to PCC. This process emits large amounts of CO2, mainly because of the energy-intensive calcination step. This thesis presents research work on the scale-up of the above-mentioned ammonium salt based calcium extraction and carbonation method, named Slag2PCC. Extending the scope of the earlier studies, it is now shown that the parameters which mainly affect the calcium utilization efficiency are the solid-to-liquid ratio of steel slag and the ammonium salt solvent solution during extraction, the mean diameter of the slag particles, and the slag composition, especially the fractions of total calcium, silicon, vanadium and iron as well as the fraction of free calcium oxide. Regarding extraction kinetics, slag particle size, solid-to-liquid ratio and molar concentration of the solvent solution have the largest effect on the reaction rate. Solvent solution concentrations above 1 mol/L NH4Cl cause leaching of other elements besides calcium. Some of these such as iron and manganese result in solution coloring, which can be disadvantageous for the quality of the PCC product. Based on chemical composition analysis of the produced PCC samples, however, the product quality is mainly similar as in commercial products. Increasing the novelty of the work, other important parameters related to assessment of the PCC quality, such as particle size distribution and crystal morphology are studied as well. As in traditional PCC precipitation process, the ratio of calcium and carbonate ions controls the particle shape; a higher value for [Ca2+]/[CO32-] prefers precipitation of calcite polymorph, while vaterite forms when carbon species are present in excess. The third main polymorph, aragonite, is only formed at elevated temperatures, above 40-50 °C. In general, longer precipitation times cause transformation of vaterite to calcite or aragonite, but also result in particle agglomeration. The chemical equilibrium of ammonium and calcium ions and dissolved ammonia controlling the solution pH affects the particle sizes, too. Initial pH of 12-13 during the carbonation favors nonagglomerated particles with a diameter of 1 μm and smaller, while pH values of 9-10 generate more agglomerates of 10-20 μm. As a part of the research work, these findings are implemented in demonstrationscale experimental process setups. For the first time, the Slag2PCC technology is tested in scale of ~70 liters instead of laboratory scale only. Additionally, design of a setup of several hundreds of liters is discussed. For these purposes various process units such as inclined settlers and filters for solids separation, pumps and stirrers for material transfer and mixing as well as gas feeding equipment are dimensioned and developed. Overall emissions reduction of the current industrial processes and good product quality as the main targets, based on the performed partial life cycle assessment (LCA), it is most beneficial to utilize low concentration ammonium salt solutions for the Slag2PCC process. In this manner the post-treatment of the products does not require extensive use of washing and drying equipment, otherwise increasing the CO2 emissions of the process. The low solvent concentration Slag2PCC process causes negative CO2 emissions; thus, it can be seen as a carbon capture and utilization (CCU) method, which actually reduces the anthropogenic CO2 emissions compared to the alternative of not using the technology. Even if the amount of steel slag is too small for any substantial mitigation of global warming, the process can have both financial and environmental significance for individual steel manufacturers as a means to reduce the amounts of emitted CO2 and landfilled steel slag. Alternatively, it is possible to introduce the carbon dioxide directly into the mixture of steel slag and ammonium salt solution. The process would generate a 60-75% pure calcium carbonate mixture, the remaining 25-40% consisting of the residual steel slag. This calcium-rich material could be re-used in ironmaking as a fluxing agent instead of natural limestone. Even though this process option would require less process equipment compared to the Slag2PCC process, it still needs further studies regarding the practical usefulness of the products. Nevertheless, compared to several other CO2 emission reduction methods studied around the world, the within this thesis developed and studied processes have the advantage of existing markets for the produced materials, thus giving also a financial incentive for applying the technology in practice.