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  • image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/
    Tamminen, Jussi;

    The intensification of copper solvent extraction was examined in this thesis. Extraction with hydroxyoximes is used in industry for copper separation. The reaction between hydroxyoxime and copper is a two-phase interfacial complexation reaction in which aqueous copper cations exchange with hydrogen ions bound to hydroxyoxime. As extraction is an interfacial reaction, its rate is dependent on the area between phases, that is, an interfacial area (A). Moreover, the rate depends on the stagnant interfacial boundary layer thickness, or diffusion path length (l di f). These variables depend on droplet size, which in turn depends on the mixing conditions in the reactor. Intensified mixing will lead to intensified extraction. Copper extraction kinetic studies were conducted in different contactors. The mass transfer into a single droplet was examined using a concentration determination method based on image analysis. The image analysis method was also used to determine mass transfer into individual droplets during breakage and coalescence experiments. The mass transfer was found to increase during droplet breakage but not during coalescence. The increased mass transfer in breakage was due to an increase in interfacial area and mixing, as the breakage of rising droplet after collision with a blade is a more violent process than coalescence. The coalescing droplets were stationary, and the interfacial area decreased, which led to a constant mass transfer during coalescence. The other devices used in the studies were a conventional stirred tank and rotor-stator devices with intensified mixing. The rotor-stator devices were used in both batch and continuous-flow reactors. The main difference between these reactors and earlier intensified extractors, such as AKUFVE1 or high speed stirring in Morton flask, is the use of a rotor-stator mixer, which leads to intensified mixing in a smaller equipment volume. The kinetic data were modeled using a reactor models developed for copper extraction. The extraction is a two-phase reaction; its equilibrium is dependent on conditions in both phases. This is indicated by a decrease in the extraction equilibrium constant as a function of aqueous phase ionic strength. In a similar manner, the increase in diluent solubility parameter leads to a decrease in equilibrium constant. The kinetic constant of copper extraction increases as a function of mixing intensity. In order to characterize mixing conditions in extraction, the droplet sizes and mixing power were measured. Measurements were made in conventional stirred tank and rotor-stator mixed continuous flow reactor and the droplet sizes were correlated with mixing power. The starting point was a single droplet extraction without mechanical stirring, which naturally yielded the lowest kinetic constant value. As expected the rate increased in a conventional stirred tank as the impeller speed increased, whereas other variables, such as feed concentrations were kept constant. The increase in impeller speed enhanced extraction both in batch and in continuous-flow rotor-stator mixers. Short residence times are required for extraction in rotor-stator reactors because of high mixing intensities. The kinetic reaction constant (k) data of all stirred reactors were dependent on specific mixing power input (P/m) to exponent 0.625. The specific mixing power input was varied in three orders of magnitude when using LIX 984 extractant. The mixing intensity was varied here in a much wider range than in typical mass transfer measurement studies. A comparison of data with other copper extractants revealed that the correlation had reasonable agreement with the kinetic data over five orders of magnitude of P/m. The kinetic constants (k) determined in different devices (single droplet, stirred tank, and rotor-stator reactors) had a good correlation with A2/l di f. The interfacial area and diffusion path length (l di f) depend on droplet size and, on mixing power. Area and diffusion path length cannot vary independently in stirred reactors. Kinetic constant dependence on interfacial area and diffusion path length illustrates the interfacial nature of solvent extraction.

    image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/ LUTPubarrow_drop_down
    image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/
    LUTPub
    2022
    Data sources: LUTPub
  • image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/
    Qin, Guodong;

    The China Fusion Engineering Test Reactor (CFETR) is a major international scientific project to solve the problem of providing the ultimate energy source for mankind. The safe and stable operation of the test reactor relies on regular monitoring and maintenance via the remote handling (RH) system. Traditional industrial robots are unable to meet the requirements of the narrow, obstacle-ridden and highly radioactive vacuum chamber. Additionally, maintenance efficiency is low, which seriously affects the process of promoting efficient automated maintenance equipment for the future commercial operation of nuclear fusion power plants. The hyper-redundant snake arm maintainers (SAM) with their excellent environmental adaptability and obstacle avoidance capabilities have attracted a lot of attention from researchers. Therefore, SAM is a highly significant and practical application in the monitoring and maintenance of large and complex equipment and confined spaces. SAM is a multi-jointed, hyper-redundant robot whose design is inspired by vertebrate and invertebrate animals in nature, such as snakes, elephant trunks, octopus tentacles and animal tails. A distinctive feature of the SAM is that the drive unit (motor, etc.) is placed outside the robot’s working space, which simplifies the overall structure of the robot and allows for a more complete streamlined posture. This externally driven “bionic tendon” makes the entire length of the arm free of excessive electronics and ideal for working in high-risk, radioactive, confined areas such as nuclear power plants. The objective of this project was to develop SAM as one of the key subsystems of the CFETR remote handling maintenance system for tasks such as visual inspection and dust removal in the complex pipeline areas of the upper window and the bottom of the divertor in the vacuum chamber. By analyzing the skeleton characteristics of the snake and its geometric form of sinuous movement, an under-actuated SAM design method is proposed. Mounting it on the quick-change interface at the end of the CFETR multipurpose overload robot (CMOR) enables many types of maintenance operations in complex and confined spaces inside the vacuum chamber. The main research content of this dissertation includes (1) A SAM structure design method. In this work, a layered drive principle was adopted to design a rigid under-actuated SAM with a highly integrated composite capstan drive system to meet the design objectives for miniaturised and lightweight components in narrow vacuum chambers. (2) A SAM dynamics decoupling algorithm. Based on the SAM structure and drive characteristics, a non-linear decoupling algorithm for the cable traction force of each joint was investigated. The cable traction force was decoupled using Lagrange’s equation, force balance, torque balance and equivalent transformation. The strong coupling between the cable traction force and the joints, the end-effector and the servo motor and the cable forces in different positions are analysed. A closed-loop control strategy based on the SAM decoupled dynamics model was designed. The simulation results show that the stability and position accuracy of the motion was significantly improved. (3) A SAM adaptive trajectory control algorithm. Based on the tractrix principle, an improved trajectory tracking algorithm and minimum joint displacement principle, an adaptive trajectory control algorithm was designed and integrated for the whole working process of the SAM. This mainly includes trajectory tracking for the process of entering the narrow space at the initial position, trajectory planning for the process of completing the task and trajectory tracking for the process of exiting the narrow space at any position. (4) A SAM rigid-flexible coupling deformation position error compensation algorithm. By using a SAM rigid-flexible coupling dynamics model, the position error of the SAM end-effector under variable loads was obtained. Based on the Levenberg-Marquardt (LM) non-linear damped least squares algorithm, various parametric errors of the SAM are identified. It was also combined with gridded workspace and linearised variable load principles to achieve variable parameter compensation for different loads and positions. Finally, SAM prototypes were developed and validated with cable traction tests, trajectory control tests, load capacity and accuracy tests. The results of the research will be used to meet the practical maintenance requirements of the CFETR vacuum chamber in the divertor and upper window complex pipeline area. The SAM designed in the project has a compact structure while offering high spatial curvature, positional accuracy and load capacity. In addition, the drive system, control system and kinematic model have been simplified to achieve bionic motion control of the robot. It can be mounted at the end of the CMOR for monitoring, maintenance, flaw detection and dust removal in the complex environment of the CFETR vacuum chamber. This is important for the stable operation, rapid inspection and automated maintenance of nuclear fusion reactors, which can accelerate the process of commercial operation of fusion reactors and realise the dream of an ultimate energy source for mankind. Expanding the scope of applications of the SAM designed in this project is of great significance in the aerospace, manufacturing, rescue and medical sectors.

    image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/ LUTPubarrow_drop_down
    image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/
    LUTPub
    2022
    Data sources: LUTPub
  • image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/
    Luhas, Jukka;

    Complex systems and changes in their structures and processes directed towards more sustainable practices have been increasingly investigated. However, such transitions towards sustainability have often been hindered by lock-in, where positive feedback locks the system into a certain outcome. In the forest-based bioeconomy transition in the boreal region, lock-in has played a two-fold role. On the one hand, it has driven force-resisting changes, whereas on the other hand, it has accelerated the implementation of novel practices. Qualitative and quantitative approaches were employed in this dissertation to identify the types, effects and related alternative outcomes of interconnections of lock-in mechanisms in the transition of complex systems towards sustainability in the context of the forest-based bioeconomy. The results identify maintaining interconnections supporting lock-in and transformational interconnections facilitating lock-out, not only in historical transition but also in future renewal. In addition, the effects of interconnections and related outcomes, such as a diversified product range and improved environmental sustainability, have been made visible in the forest-based bioeconomy transition. A wide, systemic view of this dissertation enables a comprehensive understanding of the interconnections of complex system transitions in terms of company-level practices and critical ecological limitations.

    image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/ LUTPubarrow_drop_down
    image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/
    LUTPub
    2022
    Data sources: LUTPub
  • image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/
    Eskola, Roope;

    Digitalization and globalization challenge companies to remain competitive to survive. Digitalization is disrupting traditional business models and reshaping organizational structures but also offering new opportunities to improve products. For example, various different simulation approaches are widely utilized in modern manufacturing. Using industry case examples, this dissertation examines how simulation is currently being used. The objective of the dissertation is to provide manufacturing industry insight into how simulation can be implemented from both technological and management perspectives. The included research publications cover technically oriented articles with industrial use cases for physics-based simulation and management-oriented articles that study value creation and digital business ecosystems. The included articles make several contributions regarding the development of simulation modeling as well as providing information as to how value is created via simulation in manufacturing. Therefore, the information provided is useful to promote and assist further research in the field.

    image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/ LUTPubarrow_drop_down
    image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/
    LUTPub
    2022
    Data sources: LUTPub
  • image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/
    Makarava, Iryna;

    The use of the rare-earth elements (REEs) is steadily increasing and, on the other hand, possibilities for their substitution in modern advanced technologies, especially in green energy applications, are limited. Recently, recycling REEs from spent products has become an alternative to primary mining. NdFeB magnets are of particular interest, since they are present in various forms of waste, such as end-of-life wind turbines and electric vehicles. They contain considerable amounts of REEs, mostly Nd but also Ce, Pr, Gd and Tb. The main constituent in NdFeB magnets is iron (55−60 wt-%), which makes selective REE recycling challenging. Feasible and effective technology for selective recovery of REEs from NdFeB magnets is thus needed. This dissertation focuses on electrochemical and chemical leaching as an essential step in hydrometallurgical recycling. The mechanisms in electrochemical leaching and in acid leaching were investigated. With proper adjustment of the leaching acid composition and operating conditions, effective separation of magnet constituents was achieved. Electrochemical leaching (ia=10−50 A/dm2) in a mixture of sulfuric (0.05−0.5 M) and oxalic (0.05−0.2 M) acids allowed to leach up to 99.7% of magnet with the maximum REE purity 97.2%. Applying electricity led to increase of the dissolution rate of magnets up to 10 times and removal of passive oxalate layer. In particular, a one-step electrochemical process was proposed for the recovery of REEs as cathodic REE-oxalate deposits with a yield of up to 31% and REE purity of 91−93%, while the rest of the oxalates were recovered as a powder. The unexpected result was explained by the electrostatic attraction of the positively charged REE-oxalate particles. Chemical leaching in 0.1 M H2SO4 of roasted NdFeB powder led to an REE leaching yield of 70% with a final ratio between Nd and Fe of 1/11. The selectivity in chemical leaching was explained by changes in the chemical NdFeB particle composition during roasting. In particular, NdFeO3 was observed in the porous outer layer and a higher Fe/Nd mole ratio and a lower oxygen content were observed in the inner core. These findings provide a new insight into electronic waste recycling by implementing principles of electrochemical/selective chemical leaching and helps in the search for new environmentally sustainable hydrometallurgical recycling methods.

    image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/ LUTPubarrow_drop_down
    image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/
    LUTPub
    2022
    Data sources: LUTPub
  • image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/
    Lähdeaho, Oskari;

    Sustainability has emerged as a central concern in business. Across all sectors, companies are looking for ways to reduce their negative environmental impact. Globally, transportation accounts for approximately a quarter of all produced carbon dioxide emissions. At the same time, companies are reliant on logistics and supply chains to function. Amid these concerns, companies are also recognizing opportunities to improve their competitiveness through embracing sustainability. Therefore, logistics operations can be seen as a major component of business operations that require radical changes in order to improve environmental sustainability. This doctoral thesis aims to explore ways for logistics industries to benefit from ongoing sustainability transitions. The main research strategy for this thesis is to carry out qualitative case studies, which are mixed with quantitative survey method, and supported by analytical and bibliometric studies. This mixed approach strengthens the exploratory nature of this research work. As exploration seldom has a clear or defined expected result, these approaches on their part structure the detailed results. Data triangulation with these methods allows close examination of novel phenomena in logistics industries as they unfold. These phenomena are often complex, and singular approaches give a narrow view on them. As the topics of this research are still developing, the exploratory nature offers a way to make necessary appendments to the existing theories in logistics and sustainability. The results of this thesis have been published in seven scientific articles, of which six are published in peer-reviewed scientific journals, and one is published in conference proceedings. Publication I explores business models in changing regulative and business environment. Publication II studies the case of environmental sustainability in a setting of a port and companies operating in that port. Publication III examines the development of road transport emissions development in Finnish setting. Publications IV and V study how logistics and manufacturing companies are surviving amid the Covid-19 pandemic and its implications. Publication VI is bibliometric research aimed at studying the development of scientific literature on the interplay of sustainability and innovation. Lastly, Publication VII examines logistics companies’ environmental performance and ability to self-assess in this regard. This research work showcases the emergence of sustainability as an important factor for competitiveness in the logistics industries. While some have been adapting to this change already, most are lagging. Most of the studied companies can comply with baseline regulation for now but lack the proactivity to appeal to stakeholder demands and struggle with stricter future regulations. Smaller companies especially are left in an uncomfortable situation with tightening regulations, while other events (e.g., Covid-19 and economic sanctions) are increasing the uncertainty in the studied industries. As modern societies are dependent on smaller companies acting as sub-contractors for larger enterprises, commonly beneficial solutions and policies must be found to ensure sustainability in these societies. This research work studies companies with a close case study lens with an aim to better understand the larger networks these companies form. As both logistics and sustainability are complex topics, this type of study is needed to understand the nuances and inner workings of logistics networks in relation to sustainability efforts.

    image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/ LUTPubarrow_drop_down
    image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/
    LUTPub
    2022
    Data sources: LUTPub
  • image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/
    Havukainen, Minna;

    The international battle against climate change requires action from all parties of the United Nations Framework Convention on Climate Change including the rapidly developing low-income countries. Most of the least developed countries (LDCs) have prepared nationally determined contributions (NDCs) to implement the Paris Agreement (PA). Most have strategies to tackle a fair share of the burden, regardless of the different economic challenges they face. The developed countries have made pledges to financially assist the LDCs, and several financial instruments, such as the Clean Development Mechanism (CDM) and funds have been used. Understanding the variation in commitment among LDCs would improve climate agreements and enhance global implementation of climate action. This study aims to determine the degree to which 36 LDCs implemented the PA in their NDCs, as well as the factors that determined this degree. A closer investigation of the implementation of climate strategies was conducted using Nepal as a case study. Aid-dependent Nepal is vulnerable to climate change and committed to its mitigation while pursuing democracy and development. The institutional analysis and development (IAD) framework and the institutional grammar tool (IGT) developed by Elinor Ostrom and her colleagues was applied to implement systematic assessments of institutions and the reform of national climate policy. To identify the determinants of the degree of implementation, national contexts, decision making, and patterns of interaction were investigated for six case countries. Current national institutions have not enabled effective climate change mitigation. Despite relevant political decisions being made, progress toward climate change mitigation is slow. In general, climate change has not been widely tackled across all the relevant sectors, such as waste management, traffic, and agriculture, nor across governance levels, and there is little coherence between development and climate policies. Instead, natural resource management is often prioritized for climate actions. Countries that focus more on structural changes and institutional strengthening, such as education and political and legislative instruments, are likely to implement the PA to a high degree. Therefore, encouraging countries to implement changes in the national institutional and economic arrangements required for effective climate change mitigation is crucial. A fair, inclusive procedure, a reasonable legitimate burden; variety of instruments; and the required criteria with synergy between mitigation and development provide the most effective mitigation. Building local science institutions and funding addressed effectively, even to local actors, are key options for improving the implementation of the national climate strategies of LDCs. The variation in commitment among LDCs is driven by their perspective on fair share of climate actions and climate finance.

    image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/ LUTPubarrow_drop_down
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    LUTPub
    2022
    Data sources: LUTPub
  • image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/
    Rintala, Ville;

    This work aims to improve the coupled calculations required for the modeling of nuclear reactors by producing more advanced computational tools. The study applies more advanced computational tools to more detailed modeling of the random structure in pebble bed reactors and temperature distributions formed in the fuel rods of light water reactors. As part of the calculation applied to light water reactors, a coupling code is created that links the reactor physics code utilizing the Monte Carlo method and the traditional fuel code to the coupled calculation. The calculations performed in pebble bed and light water reactors show that the Monte Carlo reactor physics code can be used as part of a calculation system that produces accurate comparison results or solves specific challenging problems where increased use of calculation capacity is justified. The comparison results calculated by such a coupling can be utilized in the future to improve the accuracy of simpler and faster calculation codes.

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    LUTPub
    2022
    Data sources: LUTPub
  • image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/
    Maksimov, Pavel;

    Recognising the unsustainable nature of the current production practices, the global economy is now steering away from fossil energy sources. Although wind and solar energy have seen tremendous improvements over the past two decades, it is not possible to harness their true potential without accounting for the generation intermittency through efficient energy storage solutions. In this context, as a liquid fuel and a versatile platform chemical, methanol can become the energy feedstock of the future. Methanol synthesis via CO2 hydrogenation could be an effective synergetic solution that would simultaneously enable efficient utilisation of renewable electricity, decouple the chemical industry from the fossil-based feedstocks, and help in reducing net CO2 emissions. The major challenge to the economically viable deployment of the process is the high demand for large amounts of H2 required for the reduction of the deeply oxidised CO2 molecule. From the perspective of technical feasibility, the process also suffers from significant thermodynamic limitations that result in low per-pass conversion, which requires large recirculation rates and increases utility consumption. As the cost of green H2 is estimated to decrease substantially in the future, overcoming the equilibrium-related limitations of CO2 hydrogenation to methanol will bring the process closer to commercialisation. Therefore, this work aims to intensify the process of CO2-based methanol production by shifting the thermodynamic equilibrium via selective in-situ removal of water that is formed as a by-product of methanol synthesis reactions. The process was implemented in a periodically operated multifunctional reactor filled with methanol synthesis catalyst and water selective adsorbent. In order to accurately capture the dynamic nature of the process, time-resolved monitoring of the product stream composition was achieved with Raman spectroscopy. In addition to the experimental study, a rigorous mathematical model of the process was developed. Key process parameters, such as pressure, temperature, gas flow velocity and catalyst-to-adsorbent ratio were analysed with the view of investigating their effect on process performance. The experimentally validated reactor model was extended to account for downstream product separation, recirculation of the unreacted gases and periodic adsorbent regeneration via pressure swing adsorption. Adiabatic and quasi-isothermal reactor configurations were considered, and a series of parametric and optimisation studies were conducted with the intent of maximising process efficiency considering the specific production rate and the purity of the obtained methanol product. The designed multifunctional reactor system was found to yield a methanol product of high purity, thereby significantly simplifying further processing. However, the acquired results indicate a clear inverse relationship between specific methanol production rate and methanol product purity, with the gas hourly space velocity being the main determining parameter in this regard. The process under study exhibits lower specific production rate compared to conventional steady-state CO2-based methanol synthesis. However, the perpass CO2 conversion and methanol yield are much higher in the periodically operated multifunctional reactor. Therefore, the investigated process demonstrates the potential to improve H2 utilisation efficiency and effectively overcome the thermodynamic limitations, which hinder CO2-based methanol production. The complex and multifaceted nature of the process requires optimisation on both reactor and process levels. This way, the results and observations reported in this work provide a sound basis for design and implementation of methanol synthesis through sorption enhanced CO2 hydrogenation.

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    LUTPub
    2022
    Data sources: LUTPub
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    Montonen, Jan-Henri;

    A mechatronic system consists of mechanics, power electronics, and control electronics. Thus, designing a mechatronic system requires multidisciplinary knowledge. As the capabilities of microprocessors have increased and prices have declined, various mechanical systems are now controlled by computer-based control systems. To be able to design a control for such applications, a model of the system is required that describes the phenomena that are being controlled. This doctoral dissertation investigates different levels of complexity for a model of a system consisting of an inverter, an electric motor, and mechanics. In addition, the study addresses the questions of how the models to be applied should be selected and how the selections affect other submodels in the system. The use of multibody-dynamics-based virtual simulation and hardware-in-theloop simulation as tools for system simulation is also studied. Further, literature references and the publications included in the dissertation are provided as examples. The included publications each report a modeling or control challenge, and different methods are employed to solve these challenges. It was shown that the selection of the model or the modeling method (such as virtual simulation) was successful in each of the presented cases. The model applied in the cases could describe accurately enough the phenomena that were being studied. Thus, after achieving an accurate enough model of the system, the control problem could be approached. The study also demonstrated that building a model requires an analysis of the system and understanding of the phenomena that are present in the system.

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    2022
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  • image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/
    Tamminen, Jussi;

    The intensification of copper solvent extraction was examined in this thesis. Extraction with hydroxyoximes is used in industry for copper separation. The reaction between hydroxyoxime and copper is a two-phase interfacial complexation reaction in which aqueous copper cations exchange with hydrogen ions bound to hydroxyoxime. As extraction is an interfacial reaction, its rate is dependent on the area between phases, that is, an interfacial area (A). Moreover, the rate depends on the stagnant interfacial boundary layer thickness, or diffusion path length (l di f). These variables depend on droplet size, which in turn depends on the mixing conditions in the reactor. Intensified mixing will lead to intensified extraction. Copper extraction kinetic studies were conducted in different contactors. The mass transfer into a single droplet was examined using a concentration determination method based on image analysis. The image analysis method was also used to determine mass transfer into individual droplets during breakage and coalescence experiments. The mass transfer was found to increase during droplet breakage but not during coalescence. The increased mass transfer in breakage was due to an increase in interfacial area and mixing, as the breakage of rising droplet after collision with a blade is a more violent process than coalescence. The coalescing droplets were stationary, and the interfacial area decreased, which led to a constant mass transfer during coalescence. The other devices used in the studies were a conventional stirred tank and rotor-stator devices with intensified mixing. The rotor-stator devices were used in both batch and continuous-flow reactors. The main difference between these reactors and earlier intensified extractors, such as AKUFVE1 or high speed stirring in Morton flask, is the use of a rotor-stator mixer, which leads to intensified mixing in a smaller equipment volume. The kinetic data were modeled using a reactor models developed for copper extraction. The extraction is a two-phase reaction; its equilibrium is dependent on conditions in both phases. This is indicated by a decrease in the extraction equilibrium constant as a function of aqueous phase ionic strength. In a similar manner, the increase in diluent solubility parameter leads to a decrease in equilibrium constant. The kinetic constant of copper extraction increases as a function of mixing intensity. In order to characterize mixing conditions in extraction, the droplet sizes and mixing power were measured. Measurements were made in conventional stirred tank and rotor-stator mixed continuous flow reactor and the droplet sizes were correlated with mixing power. The starting point was a single droplet extraction without mechanical stirring, which naturally yielded the lowest kinetic constant value. As expected the rate increased in a conventional stirred tank as the impeller speed increased, whereas other variables, such as feed concentrations were kept constant. The increase in impeller speed enhanced extraction both in batch and in continuous-flow rotor-stator mixers. Short residence times are required for extraction in rotor-stator reactors because of high mixing intensities. The kinetic reaction constant (k) data of all stirred reactors were dependent on specific mixing power input (P/m) to exponent 0.625. The specific mixing power input was varied in three orders of magnitude when using LIX 984 extractant. The mixing intensity was varied here in a much wider range than in typical mass transfer measurement studies. A comparison of data with other copper extractants revealed that the correlation had reasonable agreement with the kinetic data over five orders of magnitude of P/m. The kinetic constants (k) determined in different devices (single droplet, stirred tank, and rotor-stator reactors) had a good correlation with A2/l di f. The interfacial area and diffusion path length (l di f) depend on droplet size and, on mixing power. Area and diffusion path length cannot vary independently in stirred reactors. Kinetic constant dependence on interfacial area and diffusion path length illustrates the interfacial nature of solvent extraction.

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    2022
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    Qin, Guodong;

    The China Fusion Engineering Test Reactor (CFETR) is a major international scientific project to solve the problem of providing the ultimate energy source for mankind. The safe and stable operation of the test reactor relies on regular monitoring and maintenance via the remote handling (RH) system. Traditional industrial robots are unable to meet the requirements of the narrow, obstacle-ridden and highly radioactive vacuum chamber. Additionally, maintenance efficiency is low, which seriously affects the process of promoting efficient automated maintenance equipment for the future commercial operation of nuclear fusion power plants. The hyper-redundant snake arm maintainers (SAM) with their excellent environmental adaptability and obstacle avoidance capabilities have attracted a lot of attention from researchers. Therefore, SAM is a highly significant and practical application in the monitoring and maintenance of large and complex equipment and confined spaces. SAM is a multi-jointed, hyper-redundant robot whose design is inspired by vertebrate and invertebrate animals in nature, such as snakes, elephant trunks, octopus tentacles and animal tails. A distinctive feature of the SAM is that the drive unit (motor, etc.) is placed outside the robot’s working space, which simplifies the overall structure of the robot and allows for a more complete streamlined posture. This externally driven “bionic tendon” makes the entire length of the arm free of excessive electronics and ideal for working in high-risk, radioactive, confined areas such as nuclear power plants. The objective of this project was to develop SAM as one of the key subsystems of the CFETR remote handling maintenance system for tasks such as visual inspection and dust removal in the complex pipeline areas of the upper window and the bottom of the divertor in the vacuum chamber. By analyzing the skeleton characteristics of the snake and its geometric form of sinuous movement, an under-actuated SAM design method is proposed. Mounting it on the quick-change interface at the end of the CFETR multipurpose overload robot (CMOR) enables many types of maintenance operations in complex and confined spaces inside the vacuum chamber. The main research content of this dissertation includes (1) A SAM structure design method. In this work, a layered drive principle was adopted to design a rigid under-actuated SAM with a highly integrated composite capstan drive system to meet the design objectives for miniaturised and lightweight components in narrow vacuum chambers. (2) A SAM dynamics decoupling algorithm. Based on the SAM structure and drive characteristics, a non-linear decoupling algorithm for the cable traction force of each joint was investigated. The cable traction force was decoupled using Lagrange’s equation, force balance, torque balance and equivalent transformation. The strong coupling between the cable traction force and the joints, the end-effector and the servo motor and the cable forces in different positions are analysed. A closed-loop control strategy based on the SAM decoupled dynamics model was designed. The simulation results show that the stability and position accuracy of the motion was significantly improved. (3) A SAM adaptive trajectory control algorithm. Based on the tractrix principle, an improved trajectory tracking algorithm and minimum joint displacement principle, an adaptive trajectory control algorithm was designed and integrated for the whole working process of the SAM. This mainly includes trajectory tracking for the process of entering the narrow space at the initial position, trajectory planning for the process of completing the task and trajectory tracking for the process of exiting the narrow space at any position. (4) A SAM rigid-flexible coupling deformation position error compensation algorithm. By using a SAM rigid-flexible coupling dynamics model, the position error of the SAM end-effector under variable loads was obtained. Based on the Levenberg-Marquardt (LM) non-linear damped least squares algorithm, various parametric errors of the SAM are identified. It was also combined with gridded workspace and linearised variable load principles to achieve variable parameter compensation for different loads and positions. Finally, SAM prototypes were developed and validated with cable traction tests, trajectory control tests, load capacity and accuracy tests. The results of the research will be used to meet the practical maintenance requirements of the CFETR vacuum chamber in the divertor and upper window complex pipeline area. The SAM designed in the project has a compact structure while offering high spatial curvature, positional accuracy and load capacity. In addition, the drive system, control system and kinematic model have been simplified to achieve bionic motion control of the robot. It can be mounted at the end of the CMOR for monitoring, maintenance, flaw detection and dust removal in the complex environment of the CFETR vacuum chamber. This is important for the stable operation, rapid inspection and automated maintenance of nuclear fusion reactors, which can accelerate the process of commercial operation of fusion reactors and realise the dream of an ultimate energy source for mankind. Expanding the scope of applications of the SAM designed in this project is of great significance in the aerospace, manufacturing, rescue and medical sectors.

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    LUTPub
    2022
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    Luhas, Jukka;

    Complex systems and changes in their structures and processes directed towards more sustainable practices have been increasingly investigated. However, such transitions towards sustainability have often been hindered by lock-in, where positive feedback locks the system into a certain outcome. In the forest-based bioeconomy transition in the boreal region, lock-in has played a two-fold role. On the one hand, it has driven force-resisting changes, whereas on the other hand, it has accelerated the implementation of novel practices. Qualitative and quantitative approaches were employed in this dissertation to identify the types, effects and related alternative outcomes of interconnections of lock-in mechanisms in the transition of complex systems towards sustainability in the context of the forest-based bioeconomy. The results identify maintaining interconnections supporting lock-in and transformational interconnections facilitating lock-out, not only in historical transition but also in future renewal. In addition, the effects of interconnections and related outcomes, such as a diversified product range and improved environmental sustainability, have been made visible in the forest-based bioeconomy transition. A wide, systemic view of this dissertation enables a comprehensive understanding of the interconnections of complex system transitions in terms of company-level practices and critical ecological limitations.

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    2022
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    Eskola, Roope;

    Digitalization and globalization challenge companies to remain competitive to survive. Digitalization is disrupting traditional business models and reshaping organizational structures but also offering new opportunities to improve products. For example, various different simulation approaches are widely utilized in modern manufacturing. Using industry case examples, this dissertation examines how simulation is currently being used. The objective of the dissertation is to provide manufacturing industry insight into how simulation can be implemented from both technological and management perspectives. The included research publications cover technically oriented articles with industrial use cases for physics-based simulation and management-oriented articles that study value creation and digital business ecosystems. The included articles make several contributions regarding the development of simulation modeling as well as providing information as to how value is created via simulation in manufacturing. Therefore, the information provided is useful to promote and assist further research in the field.

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    LUTPub
    2022
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    Makarava, Iryna;

    The use of the rare-earth elements (REEs) is steadily increasing and, on the other hand, possibilities for their substitution in modern advanced technologies, especially in green energy applications, are limited. Recently, recycling REEs from spent products has become an alternative to primary mining. NdFeB magnets are of particular interest, since they are present in various forms of waste, such as end-of-life wind turbines and electric vehicles. They contain considerable amounts of REEs, mostly Nd but also Ce, Pr, Gd and Tb. The main constituent in NdFeB magnets is iron (55−60 wt-%), which makes selective REE recycling challenging. Feasible and effective technology for selective recovery of REEs from NdFeB magnets is thus needed. This dissertation focuses on electrochemical and chemical leaching as an essential step in hydrometallurgical recycling. The mechanisms in electrochemical leaching and in acid leaching were investigated. With proper adjustment of the leaching acid composition and operating conditions, effective separation of magnet constituents was achieved. Electrochemical leaching (ia=10−50 A/dm2) in a mixture of sulfuric (0.05−0.5 M) and oxalic (0.05−0.2 M) acids allowed to leach up to 99.7% of magnet with the maximum REE purity 97.2%. Applying electricity led to increase of the dissolution rate of magnets up to 10 times and removal of passive oxalate layer. In particular, a one-step electrochemical process was proposed for the recovery of REEs as cathodic REE-oxalate deposits with a yield of up to 31% and REE purity of 91−93%, while the rest of the oxalates were recovered as a powder. The unexpected result was explained by the electrostatic attraction of the positively charged REE-oxalate particles. Chemical leaching in 0.1 M H2SO4 of roasted NdFeB powder led to an REE leaching yield of 70% with a final ratio between Nd and Fe of 1/11. The selectivity in chemical leaching was explained by changes in the chemical NdFeB particle composition during roasting. In particular, NdFeO3 was observed in the porous outer layer and a higher Fe/Nd mole ratio and a lower oxygen content were observed in the inner core. These findings provide a new insight into electronic waste recycling by implementing principles of electrochemical/selective chemical leaching and helps in the search for new environmentally sustainable hydrometallurgical recycling methods.

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    2022
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    Lähdeaho, Oskari;

    Sustainability has emerged as a central concern in business. Across all sectors, companies are looking for ways to reduce their negative environmental impact. Globally, transportation accounts for approximately a quarter of all produced carbon dioxide emissions. At the same time, companies are reliant on logistics and supply chains to function. Amid these concerns, companies are also recognizing opportunities to improve their competitiveness through embracing sustainability. Therefore, logistics operations can be seen as a major component of business operations that require radical changes in order to improve environmental sustainability. This doctoral thesis aims to explore ways for logistics industries to benefit from ongoing sustainability transitions. The main research strategy for this thesis is to carry out qualitative case studies, which are mixed with quantitative survey method, and supported by analytical and bibliometric studies. This mixed approach strengthens the exploratory nature of this research work. As exploration seldom has a clear or defined expected result, these approaches on their part structure the detailed results. Data triangulation with these methods allows close examination of novel phenomena in logistics industries as they unfold. These phenomena are often complex, and singular approaches give a narrow view on them. As the topics of this research are still developing, the exploratory nature offers a way to make necessary appendments to the existing theories in logistics and sustainability. The results of this thesis have been published in seven scientific articles, of which six are published in peer-reviewed scientific journals, and one is published in conference proceedings. Publication I explores business models in changing regulative and business environment. Publication II studies the case of environmental sustainability in a setting of a port and companies operating in that port. Publication III examines the development of road transport emissions development in Finnish setting. Publications IV and V study how logistics and manufacturing companies are surviving amid the Covid-19 pandemic and its implications. Publication VI is bibliometric research aimed at studying the development of scientific literature on the interplay of sustainability and innovation. Lastly, Publication VII examines logistics companies’ environmental performance and ability to self-assess in this regard. This research work showcases the emergence of sustainability as an important factor for competitiveness in the logistics industries. While some have been adapting to this change already, most are lagging. Most of the studied companies can comply with baseline regulation for now but lack the proactivity to appeal to stakeholder demands and struggle with stricter future regulations. Smaller companies especially are left in an uncomfortable situation with tightening regulations, while other events (e.g., Covid-19 and economic sanctions) are increasing the uncertainty in the studied industries. As modern societies are dependent on smaller companies acting as sub-contractors for larger enterprises, commonly beneficial solutions and policies must be found to ensure sustainability in these societies. This research work studies companies with a close case study lens with an aim to better understand the larger networks these companies form. As both logistics and sustainability are complex topics, this type of study is needed to understand the nuances and inner workings of logistics networks in relation to sustainability efforts.

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    2022
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    Havukainen, Minna;

    The international battle against climate change requires action from all parties of the United Nations Framework Convention on Climate Change including the rapidly developing low-income countries. Most of the least developed countries (LDCs) have prepared nationally determined contributions (NDCs) to implement the Paris Agreement (PA). Most have strategies to tackle a fair share of the burden, regardless of the different economic challenges they face. The developed countries have made pledges to financially assist the LDCs, and several financial instruments, such as the Clean Development Mechanism (CDM) and funds have been used. Understanding the variation in commitment among LDCs would improve climate agreements and enhance global implementation of climate action. This study aims to determine the degree to which 36 LDCs implemented the PA in their NDCs, as well as the factors that determined this degree. A closer investigation of the implementation of climate strategies was conducted using Nepal as a case study. Aid-dependent Nepal is vulnerable to climate change and committed to its mitigation while pursuing democracy and development. The institutional analysis and development (IAD) framework and the institutional grammar tool (IGT) developed by Elinor Ostrom and her colleagues was applied to implement systematic assessments of institutions and the reform of national climate policy. To identify the determinants of the degree of implementation, national contexts, decision making, and patterns of interaction were investigated for six case countries. Current national institutions have not enabled effective climate change mitigation. Despite relevant political decisions being made, progress toward climate change mitigation is slow. In general, climate change has not been widely tackled across all the relevant sectors, such as waste management, traffic, and agriculture, nor across governance levels, and there is little coherence between development and climate policies. Instead, natural resource management is often prioritized for climate actions. Countries that focus more on structural changes and institutional strengthening, such as education and political and legislative instruments, are likely to implement the PA to a high degree. Therefore, encouraging countries to implement changes in the national institutional and economic arrangements required for effective climate change mitigation is crucial. A fair, inclusive procedure, a reasonable legitimate burden; variety of instruments; and the required criteria with synergy between mitigation and development provide the most effective mitigation. Building local science institutions and funding addressed effectively, even to local actors, are key options for improving the implementation of the national climate strategies of LDCs. The variation in commitment among LDCs is driven by their perspective on fair share of climate actions and climate finance.

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    2022
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    Rintala, Ville;

    This work aims to improve the coupled calculations required for the modeling of nuclear reactors by producing more advanced computational tools. The study applies more advanced computational tools to more detailed modeling of the random structure in pebble bed reactors and temperature distributions formed in the fuel rods of light water reactors. As part of the calculation applied to light water reactors, a coupling code is created that links the reactor physics code utilizing the Monte Carlo method and the traditional fuel code to the coupled calculation. The calculations performed in pebble bed and light water reactors show that the Monte Carlo reactor physics code can be used as part of a calculation system that produces accurate comparison results or solves specific challenging problems where increased use of calculation capacity is justified. The comparison results calculated by such a coupling can be utilized in the future to improve the accuracy of simpler and faster calculation codes.

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    2022
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    Maksimov, Pavel;

    Recognising the unsustainable nature of the current production practices, the global economy is now steering away from fossil energy sources. Although wind and solar energy have seen tremendous improvements over the past two decades, it is not possible to harness their true potential without accounting for the generation intermittency through efficient energy storage solutions. In this context, as a liquid fuel and a versatile platform chemical, methanol can become the energy feedstock of the future. Methanol synthesis via CO2 hydrogenation could be an effective synergetic solution that would simultaneously enable efficient utilisation of renewable electricity, decouple the chemical industry from the fossil-based feedstocks, and help in reducing net CO2 emissions. The major challenge to the economically viable deployment of the process is the high demand for large amounts of H2 required for the reduction of the deeply oxidised CO2 molecule. From the perspective of technical feasibility, the process also suffers from significant thermodynamic limitations that result in low per-pass conversion, which requires large recirculation rates and increases utility consumption. As the cost of green H2 is estimated to decrease substantially in the future, overcoming the equilibrium-related limitations of CO2 hydrogenation to methanol will bring the process closer to commercialisation. Therefore, this work aims to intensify the process of CO2-based methanol production by shifting the thermodynamic equilibrium via selective in-situ removal of water that is formed as a by-product of methanol synthesis reactions. The process was implemented in a periodically operated multifunctional reactor filled with methanol synthesis catalyst and water selective adsorbent. In order to accurately capture the dynamic nature of the process, time-resolved monitoring of the product stream composition was achieved with Raman spectroscopy. In addition to the experimental study, a rigorous mathematical model of the process was developed. Key process parameters, such as pressure, temperature, gas flow velocity and catalyst-to-adsorbent ratio were analysed with the view of investigating their effect on process performance. The experimentally validated reactor model was extended to account for downstream product separation, recirculation of the unreacted gases and periodic adsorbent regeneration via pressure swing adsorption. Adiabatic and quasi-isothermal reactor configurations were considered, and a series of parametric and optimisation studies were conducted with the intent of maximising process efficiency considering the specific production rate and the purity of the obtained methanol product. The designed multifunctional reactor system was found to yield a methanol product of high purity, thereby significantly simplifying further processing. However, the acquired results indicate a clear inverse relationship between specific methanol production rate and methanol product purity, with the gas hourly space velocity being the main determining parameter in this regard. The process under study exhibits lower specific production rate compared to conventional steady-state CO2-based methanol synthesis. However, the perpass CO2 conversion and methanol yield are much higher in the periodically operated multifunctional reactor. Therefore, the investigated process demonstrates the potential to improve H2 utilisation efficiency and effectively overcome the thermodynamic limitations, which hinder CO2-based methanol production. The complex and multifaceted nature of the process requires optimisation on both reactor and process levels. This way, the results and observations reported in this work provide a sound basis for design and implementation of methanol synthesis through sorption enhanced CO2 hydrogenation.

    image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/ LUTPubarrow_drop_down
    image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/
    LUTPub
    2022
    Data sources: LUTPub
  • image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/
    Montonen, Jan-Henri;

    A mechatronic system consists of mechanics, power electronics, and control electronics. Thus, designing a mechatronic system requires multidisciplinary knowledge. As the capabilities of microprocessors have increased and prices have declined, various mechanical systems are now controlled by computer-based control systems. To be able to design a control for such applications, a model of the system is required that describes the phenomena that are being controlled. This doctoral dissertation investigates different levels of complexity for a model of a system consisting of an inverter, an electric motor, and mechanics. In addition, the study addresses the questions of how the models to be applied should be selected and how the selections affect other submodels in the system. The use of multibody-dynamics-based virtual simulation and hardware-in-theloop simulation as tools for system simulation is also studied. Further, literature references and the publications included in the dissertation are provided as examples. The included publications each report a modeling or control challenge, and different methods are employed to solve these challenges. It was shown that the selection of the model or the modeling method (such as virtual simulation) was successful in each of the presented cases. The model applied in the cases could describe accurately enough the phenomena that were being studied. Thus, after achieving an accurate enough model of the system, the control problem could be approached. The study also demonstrated that building a model requires an analysis of the system and understanding of the phenomena that are present in the system.

    image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/ LUTPubarrow_drop_down
    image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/
    LUTPub
    2022
    Data sources: LUTPub
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