19 resultados para Isolated carbonate platforms

em Doria (National Library of Finland DSpace Services) - National Library of Finland, Finland


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Selostus: Vehnästä ja ohrasta eristettyjen F. avenaceum -punahomekantojen analysointi UP-PCR-menetelmällä

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Selostus: Häkin koon ja häkissä olevien näköesteiden vaikutus tarhattujen hopeakettujen makuuhyllyn käyttöön

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Selostus: Näköesteen vaikutus sinikettujen hyllynkäyttöön

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Viime aikoina matkapuhelimet ovat alkaneet tukea Javaa matkapuhelinsovellusten ohjelmointikielenä. Javan perusajatus on, että kerran käännetty sovellus voidaan suorittaa useilla laitealustoilla ilman uudelleenkääntämisen tarvetta. Jotta sovellukset voisivat toimia uudella alustalla, niiden käyttämät kirjastot tulee siirtää uudelle alustalle. Tämä diplomityö tutkii tämänkaltaiseen siirtoprojektiin liittyviä asioita. Diplomityön aikana käyttöliittymäkirjasto siirrettiin olemassa olleelta alustalta kahdelle uudelle alustalle. Toinen uusista alustoista oli vanhan alustan uusi versio, ja toinen oli kokonaan uusi alusta. Ohjelmiston siirtämistä helpottaa jos alkuperäinen ohjelmisto on suunniteltu siirrettävyyttä silmälläpitäen. Varsinaiset ohjelmaan tehtävät muutokset ovat tällöin helppoja tehdä. Hyvälaatuisen lopputuloksen saaminen vaatii kuitenkin aina että ohjelmisto myös testataan huolellisesti.

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In this report, we summarize results of our part of the ÄLYKOP-project on customer value creation in the intersection of the health care, ICT, forest and energy industries. The research directs to describe how industry transformation and convergence create new possibilities, business opportunities and even new industries.The report consists of findings which are presented former in academic publications. The publication discusses on customer value, service provision and resource basis of the novel concepts through multiple theorethical frameworks. The report is divided into three maim sections which are theoretical background, discussion on health care industry and evaluations regarding novel smart home concepts. Transaction cost economics and Resource- Based view on the firm provides the theoretical basis to analyze the prescribed phenomena. The health care industry analysis describes the most important changes in the demand conditions of health care services, and explores the features that are likely to open new business opportunities for a solution provider. The third part of the report on the smart home business provides illustrations few potential concepts that can be considered to provide solutions to economical problems which arise from aging of population. The results provide several recommendations for the smart home platform developers in public and private sectors. By the analysis, public organizations dominate service provision and private markets are emergent state at present. We argue that public-private partnerships are nececssary for creating key suppliers. Indeed, paying attion on appropriate regulation, service specifications and technology standards would foster diffusion of new services. The dynamics of the service provision networks is driven by need for new capabiltities which are required for adapting business concepts to new competitive situation. Finally, the smart home framework revealed links between conventionally distant business areas such as health care and energy distribution. The platform integrates functionalities different for purposes which however apply same resource basis.

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Fuel cells are a promising alternative for clean and efficient energy production. A fuel cell is probably the most demanding of all distributed generation power sources. It resembles a solar cell in many ways, but sets strict limits to current ripple, common mode voltages and load variations. The typically low output voltage from the fuel cell stack needs to be boosted to a higher voltage level for grid interfacing. Due to the high electrical efficiency of the fuel cell, there is a need for high efficiency power converters, and in the case of low voltage, high current and galvanic isolation, the implementation of such converters is not a trivial task. This thesis presents galvanically isolated DC-DC converter topologies that have favorable characteristics for fuel cell usage and reviews the topologies from the viewpoint of electrical efficiency and cost efficiency. The focus is on evaluating the design issues when considering a single converter module having large current stresses. The dominating loss mechanism in low voltage, high current applications is conduction losses. In the case of MOSFETs, the conduction losses can be efficiently reduced by paralleling, but in the case of diodes, the effectiveness of paralleling depends strongly on the semiconductor material, diode parameters and output configuration. The transformer winding losses can be a major source of losses if the windings are not optimized according to the topology and the operating conditions. Transformer prototyping can be expensive and time consuming, and thus it is preferable to utilize various calculation methods during the design process in order to evaluate the performance of the transformer. This thesis reviews calculation methods for solid wire, litz wire and copper foil winding losses, and in order to evaluate the applicability of the methods, the calculations are compared against measurements and FEM simulations. By selecting a proper calculation method for each winding type, the winding losses can be predicted quite accurately before actually constructing the transformer. The transformer leakage inductance, the amount of which can also be calculated with reasonable accuracy, has a significant impact on the semiconductor switching losses. Therefore, the leakage inductance effects should also be taken into account when considering the overall efficiency of the converter. It is demonstrated in this thesis that although there are some distinctive differences in the loss distributions between the converter topologies, the differences in the overall efficiency can remain within a range of a few percentage points. However, the optimization effort required in order to achieve the high efficiencies is quite different in each topology. In the presence of practical constraints such as manufacturing complexity or cost, the question of topology selection can become crucial.

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In accordance with the Moore's law, the increasing number of on-chip integrated transistors has enabled modern computing platforms with not only higher processing power but also more affordable prices. As a result, these platforms, including portable devices, work stations and data centres, are becoming an inevitable part of the human society. However, with the demand for portability and raising cost of power, energy efficiency has emerged to be a major concern for modern computing platforms. As the complexity of on-chip systems increases, Network-on-Chip (NoC) has been proved as an efficient communication architecture which can further improve system performances and scalability while reducing the design cost. Therefore, in this thesis, we study and propose energy optimization approaches based on NoC architecture, with special focuses on the following aspects. As the architectural trend of future computing platforms, 3D systems have many bene ts including higher integration density, smaller footprint, heterogeneous integration, etc. Moreover, 3D technology can signi cantly improve the network communication and effectively avoid long wirings, and therefore, provide higher system performance and energy efficiency. With the dynamic nature of on-chip communication in large scale NoC based systems, run-time system optimization is of crucial importance in order to achieve higher system reliability and essentially energy efficiency. In this thesis, we propose an agent based system design approach where agents are on-chip components which monitor and control system parameters such as supply voltage, operating frequency, etc. With this approach, we have analysed the implementation alternatives for dynamic voltage and frequency scaling and power gating techniques at different granularity, which reduce both dynamic and leakage energy consumption. Topologies, being one of the key factors for NoCs, are also explored for energy saving purpose. A Honeycomb NoC architecture is proposed in this thesis with turn-model based deadlock-free routing algorithms. Our analysis and simulation based evaluation show that Honeycomb NoCs outperform their Mesh based counterparts in terms of network cost, system performance as well as energy efficiency.

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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.

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Paper-based analytical technologies enable quantitative and rapid analysis of analytes from various application areas including healthcare, environmental monitoring and food safety. Because paper is a planar, flexible and light weight substrate, the devices can be transported and disposed easily. Diagnostic devices are especially valuable in resourcelimited environments where diagnosis as well as monitoring of therapy can be made even without electricity by using e.g. colorimetric assays. On the other hand, platforms including printed electrodes can be coupled with hand-held readers. They enable electrochemical detection with improved reliability, sensitivity and selectivity compared with colorimetric assays. In this thesis, different roll-to-roll compatible printing technologies were utilized for the fabrication of low-cost paper-based sensor platforms. The platforms intended for colorimetric assays and microfluidics were fabricated by patterning the paper substrates with hydrophobic vinyl substituted polydimethylsiloxane (PDMS) -based ink. Depending on the barrier properties of the substrate, the ink either penetrates into the paper structure creating e.g. microfluidic channel structures or remains on the surface creating a 2D analog of a microplate. The printed PDMS can be cured by a roll-ro-roll compatible infrared (IR) sintering method. The performance of these platforms was studied by printing glucose oxidase-based ink on the PDMS-free reaction areas. The subsequent application of the glucose analyte changed the colour of the white reaction area to purple with the colour density and intensity depending on the concentration of the glucose solution. Printed electrochemical cell platforms were fabricated on paper substrates with appropriate barrier properties by inkjet-printing metal nanoparticle based inks and by IR sintering them into conducting electrodes. Printed PDMS arrays were used for directing the liquid analyte onto the predetermined spots on the electrodes. Various electrochemical measurements were carried out both with the bare electrodes and electrodes functionalized with e.g. self assembled monolayers. Electrochemical glucose sensor was selected as a proof-of-concept device to demonstrate the potential of the printed electronic platforms.

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Esitys KDK-käytettävyystyöryhmän järjestämässä seminaarissa: Miten käyttäjien toiveet haastavat metatietokäytäntöjämme? / How users' expectations challenge our metadata practices? 30.9.2014.

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Smart phones became part and parcel of our life, where mobility provides a freedom of not being bounded by time and space. In addition, number of smartphones produced each year is skyrocketing. However, this also created discrepancies or fragmentation among devices and OSes, which in turn made an exceeding hard for developers to deliver hundreds of similar featured applications with various versions for the market consumption. This thesis is an attempt to investigate whether cloud based mobile development platforms can mitigate and eventually eliminate fragmentation challenges. During this research, we have selected and analyzed the most popular cloud based development platforms and tested integrated cloud features. This research showed that cloud based mobile development platforms may able to reduce mobile fragmentation and enable to utilize single codebase to deliver a mobile application for different platforms.

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Carbon dioxide is regarded, nowadays, as a primary anthropogenic greenhouse gas leading to global warming. Hence, chemical fixation of CO2 has attracted much attention as a possible way to manufacture useful chemicals. One of the most interesting approaches of CO2 transformations is the synthesis of organic carbonates. Since conventional production technologies of these compounds involve poisonous phosgene and carbon monoxide, there is a need to develop novel synthetic methods that would better match the principles of "Green Chemistry" towards protection of the environment and human health. Over the years, synthesis of dimethyl carbonate was under intensive investigation in the academia and industry. Therefore, this study was entirely directed towards equally important homologue of carbonic esters family namely diethyl carbonate (DEC). Novel synthesis method of DEC starting from ethanol and CO2 over heterogeneous catalysts based on ceria (CeO2) was studied in the batch reactor. However, the plausible drawback of the reaction is thermodynamic limitations. The calculated values revealed that the reaction is exothermic (ΔrHØ298K = ─ 16.6 J/ ) and does not occur spontaneously at rooms temperature (ΔrGØ 298K = 35.85 kJ/mol). Moreover, co-produced water easily shifts the reaction equilibrium towards reactants excluding achievement of high yields of the carbonate. Therefore, in-situ dehydration has been applied using butylene oxide as a chemical water trap. A 9-fold enhancement in the amount of DEC was observed upon introduction of butylene oxide to the reaction media in comparison to the synthetic method without any water removal. This result confirms that reaction equilibrium was shifted in favour of the desired product and thermodynamic boundaries of the reaction were suppressed by using butylene oxide as a water scavenger. In order to obtain insight into the reaction network, the kinetic experiments were performed over commercial cerium oxide. On the basis of the selectivity/conversion profile it could be concluded that the one-pot synthesis of diethyl carbonate from ethanol, CO2 and butylene oxide occurs via a consecutive route involving cyclic carbonate as an intermediate. Since commercial cerium oxide suffers from the deactivation problems already after first reaction cycle, in-house CeO2 was prepared applying room temperature precipitation technique. Variation of the synthesis parameters such as synthesis time, calcination temperature and pH of the reaction solution turned to have considerable influence on the physico-chemical and catalytic properties of CeO2. The increase of the synthesis time resulted in high specific surface area of cerium oxide and catalyst prepared within 50 h exhibited the highest amount of basic sites on its surface. Furthermore, synthesis under pH 11 yielded cerium oxide with the highest specific surface area, 139 m2/g, among all prepared catalysts. Moreover, CeO2─pH11 catalyst demonstrated the best catalytic activity and 2 mmol of DEC was produced at 180 oC and 9 MPa of the final reaction pressure. In addition, ceria-supported onto high specific surface area silicas MCM-41, SBA-15 and silica gel were synthesized and tested for the first time as catalysts in the synthesis of DEC. Deposition of cerium oxide on MCM-41 and SiO2 supports resulted in a substantial increase of the alkalinity of the carrier materials. Hexagonal SBA-15 modified with 20 wt % of ceria exhibited the second highest basicity in the series of supported catalysts. Evaluation of the catalytic activity of ceria-supported catalysts showed that reaction carried out over 20 wt % CeO2-SBA-15 generated the highest amount of DEC.