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    Dimensioning a solar farm in the vicinity of wind production for a hybrid renewable energy system
    (2024-01-22) Niutanen, Mikael; Laurila, Heidi; Insinööritieteiden korkeakoulu; Järvinen, Mika
    Wind power as a renewable energy source is growing steadily in Finland. It is installed in several hundreds of megawatts every year, yet due to its irregularity, it is unable to cover energy demand at all times. However, solar power has developed in recent years, making it a viable even in the Northern areas. The technological improvements and decreasing module prices are making them financially viable even in locations with less radiation. Furthermore, the production of these two energy sources is negatively correlated, allowing combining them into a hybrid power system. In this thesis, a methodology and a tool were developed for dimensioning solar power in different hybrid projects. The sizing considers the restrictions set by the electricity grid and the project area, which are used to predict the optimal amount of solar power in the hybrid system. The dimensioning is based on minimising the LCOE, i.e., the levelized cost of electricity. The modelling utilises hourly production estimations based on historical wind and irradiance data, which can be used to estimate hourly production profile. In the transmission of electricity, the infrastructure of the wind power project is utilised, which enables lower capital costs for the solar investment. The feasibility was assessed in the form of a case study. The developed methods were reproducibly suitable for dimensioning the solar park. In the case study, the optimal solar power capacity was defined at 75% in relation to the rated wind capacity. In this result, electricity transmission was increased by 23% compared to the individual wind power project, demonstrating a lesser requirement for the electric grid. Solar production was calculated to lose on average 1% of its production due to the constraints imposed by the project.
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    Preventing haul truck-related fatalities in open pit mining using gamified training simulation
    (2024-01-22) Vos, Lennart; Soleymani Shishvan, Masoud; Buxton, Mike; Insinööritieteiden korkeakoulu; Rinne, Mikael
    Haul truck driving remains to be the most dangerous occupation in the mining industry (Kecojevic et al., 2007), leading in fatalities over other occupations in the mining industry. As the transition to autonomous haul trucks over the coming decades will not address this problem today, an immediate solution is needed that can be adopted at short notice to help aid in minimizing haul truck accidents. A gamified training simulator was developed that teaches haul truck drivers how to handle the hazardous situations that lead to the most injuries in the mine environment. The simulated nature of the training method allows truck drivers to gain knowledge on hazardous situations and immediately put them into practice by applying the gained knowledge during the different levels. Gamification aspects like a score system and progression through levels were added to increase engagement during the training simulation. A statistical analysis was made on haul truck accidents from 1983 until 2022. The accidents that proved to be most relevant were included in the content of the training software. A training software was developed using Unreal Engine 5, where trucks could be driven using a Thrustmaster T150 Pro steering wheel and driving pedals. 18 participants from ages 19-65 underwent the training program and two tests of identical difficulty were taken before and after undergoing the training, in order to make a judgement on the progress of the participants by undergoing the training simulation. Participants were judged based on the number of crashes and traffic violations committed, attempts required to complete the test, as well as the time taken to finish the test. A score was calculated based on these factors providing an overall judgement of the participants’ level of skill. Average skill of participants increased by undergoing the gamified training, and training showed particularly good progress for underperformers in the initial test. After completing the gamified training the average score of participants was notably higher and the standard deviation was notably lower. It was concluded that all participants were brought to a comparably high level after completing the training.
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    Development of stress concentration factors for geared shafts
    (2024-01-22) Pandey, Durgesh; Musharraf, Mashrura; Insinööritieteiden korkeakoulu; Remes, Heikki
    The presence of geometrical irregularities in shafts, such as shaft shoulders, grooves, and keyways, disrupts the homogeneity of stress distribution, creating areas with stress concentrations. This intricate connection between geometric complexities and stress gradients is crucial as it significantly impacts both the initiation and propagation of cracks in shafts. Consequently, the development of a precise and comprehensive calculation method for stress concentration is always imperative to ensure the integrity of mechanical design. By comprehending and unifying these interconnected factors, engineers can make well-informed design decisions that contribute to the enhanced reliability and durability of shaft-integrated systems. This thesis investigated modern techniques for assessing stress concentrations in shafts and introduced an Artificial Intelligence (AI) based approach to compute the Stress Concentration Factor (SCF) in geared shafts subjected to the combination of bending, axial, torsional, and shear stresses. The proposed calculation method employs Artificial Neural Network (ANN) models trained on stress datasets obtained from Finite Element Analysis (FEA) of industrial gearbox shafts. These models can predict SCFs for both familiar and unfamiliar geometric irregularities within the confines of the training dataset’s limits. Comparative analyses with results from conventional analytical approaches demonstrated that the stress concentration factors obtained through the proposed AI-based method are both valid and reliable. Notably, this method proves its validity for handling combined stresses and exhibits applicability to complex geometric conditions, including keyways with shaft shoulders, setting it apart from the underlined analytical methods.
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    Techno economic evaluation of 3D-printed metal components in shipbuilding
    (2024-01-22) Kohosalmi, Tuomas; Hämäläinen, Werner; Salmi, Mika; Insinööritieteiden korkeakoulu; Remes, Heikki
    The purpose of the thesis is to develop an evaluation method for assessing the technical and economic aspects of using additive manufacturing to fabricate structural components for ships. Adopting new manufacturing processes in an established field is difficult without demonstrating the benefits of the new process. This thesis researches the different technologies for additive manufacturing and methods to evaluate their benefits. In a case study the viability of an AM solution is studied compared to a conventionally manufactured component. Structural analysis using the finite element method was done and topology optimization was used to improve the concept. Additive manufacturing simulation and expert analysis was used to evaluate the costs and manufacturing time of the alternatives. Finally, analytical hierarchy process was used to compare the technical, economic, and psychological criteria of each alternative. The case study used the developed Techno-Economic Assessment model to compare a conventional steel element with a topology optimized steel AM element. The element manufactured using the AM indicated potential weight savings of 72%, but also the freedom of design enabled by the AM provided additional value for the component in terms of aesthetic design and capabilities of the topological optimization. The analytical comparison of the alternatives shows that both elements are equally viable for the application, with the conventional element being cheaper and faster to produce, but the AM element being lighter and allowing for more flexibility in the design.
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    Investigation of process parameters for optimizing the mechanical properties of 3D-printed BASF 316L feedstock
    (2024-01-22) Gopalsamy, Pradeep Kumar; Spor, Stefan; Stampfl, Jürgen; Insinööritieteiden korkeakoulu; Salmi, Mika
    Additive manufacturing is a revolutionizing production method where the product is built by adding materials layer by layer. It has the advantage of producing complex parts with great freedom of design. The current research Fused Deposition Modelling (FDM) of BASF 316L was studied to improve mechanical strength. The print parameters print speed, print temperature, extrusion multiplier, infill pattern, and print orientation were investigated. The experiments were carried out using the Taguchi Design of Experiments (DOE) L9 orthogonal arrays in each print orientation, which amounted to eighteen experimental runs. The tensile strength for all specimens was conducted, and Analysis of Variance(ANOVA) shows a mathematical relationship between the print parameters and response. The print parameter print speed is the most significant factor, and the print temperature has the least significance in determining tensile strength. The optimal parameters for higher tensile strength is print speed-30mm/s, print temperature-270°C, Extrusion multiplier-130%,infill pattern-concentric and print orientation- On-edge.
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    Optimised fuel consumption of hauling mobile equipment achieved from speed optimisation using Simulated Annealing
    (2024-01-22) Vis, Floris Calvin; Buxton, Mike; Soleymani Shishvan, Masoud; Insinööritieteiden korkeakoulu; Rinne, Mikael
    The mining industry is a significant contributor to greenhouse gas emissions and operational costs. The transportation of materials within mining operations, especially using diesel-powered trucks, accounts for a substantial portion of both emissions and costs. Optimizing fuel consumption in this context is crucial for environmental sustainability and financial efficiency. While there is some existing research on minimizing fuel consumption in mining operations, most of these studies prioritize production over fuel efficiency. Additionally, there is a lack of solutions addressing real-time dispatch problems while also minimizing fuel consumption. This thesis proposes the development of a model to optimize truck speeds in mining operations, with the primary goal of reducing fuel consumption. The focus is on minimizing waiting times for trucks at loading stations by adjusting their speeds using a metaheuristic algorithm, specifically Simulated Annealing (SA). To achieve this, a discrete event simulation (DES) model made in HaulSim to replicate a simplified mining site in Nevada, USA. The simulation includes Caterpillar 793 series trucks. The SA algorithm is applied to find optimal truck speeds, with the aim of reducing fuel consumption with the same level of production. The hypothesis is that lowering truck speeds in mining environments with queueing trucks can significantly reduce fuel consumption. The study explores how speed optimization impacts efficiency across different mining conditions, identifies the most effective optimization techniques, and quantifies potential fuel savings. The research reveals a 27-32% reduction in fuel consumption across various truck scenarios. However, these findings should be interpreted cautiously due to limitations in data constraints and modelling simplifications. In conclusion, the study highlights the effectiveness of SA in optimizing truck speeds and the potential for substantial fuel savings in mining operations. We recommend the integration of Artificial Neural Networks (ANNs) for a more nuanced approach to fuel consumption estimation and optimization, considering factors like road maintenance intervals and payload. This synergistic approach, combining metaheuristics and machine learning techniques, aligns with sustainable practices in the mining industry and offers promising avenues for further research and application.
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    Robot-aided hyperspectral imaging for mineral exploration in underground mining environments
    (2024-01-22) Dieters, Sibren; Schmiedel, Tobias; Insinööritieteiden korkeakoulu; Leveinen, Jussi
    New mining and exploration projects have revived across Europe with an increasing demand for critical raw materials driven by the energy transition and unstable political conditions. Hyperspectral imaging proves to be an excellent tool for quick and efficient non-invasive mineral exploration. By mounting hyperspectral- and LiDAR sensors on drones and other robots, inaccessible and dangerous areas can safely be mapped for geological information. With increasingly deeper and more hazardous underground mines, a robot-aided hyperspectral mineral exploration method in underground environments is needed. This study configures a Cubert X20P hyperspectral camera (VNIR) and VLP16 LiDAR on the versatile Boston Dynamics Spot robot, creating a multi-sensor robotic platform for data acquisition in underground mining environments. A data workflow is proposed and applied to the granite greisen rocks of the Zinnwald/Cinnovec mine (Germany). Combining hyperspectral and geometric data provides unique 3D hypercloud results interpreted for mineral and structural features. Hyperspectral analysis successfully identifies iron and clay minerals along with multiple vein and fault structures. A remote mineral exploration method in underground mines significantly improves safety by keeping the operator away from hazardous areas. The proposed platform and workflow show potential to contribute to underground mineral exploration,especially if future improvements in data quality and autonomous capabilities are made.
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    Osallistieto suunnitteluprosessissa. Suunnittelijoiden kokemuksia vuorovaikutuksen jatkumosta Espoon Viiskorven maankäytön suunnittelussa
    (2024-01-22) Salomaa, Venla; Nummi, Pilvi; Rossi, Saana; Insinööritieteiden korkeakoulu; Kyttä, Marketta
    Nykyisissä maankäytön suunnitteluprosessien vuorovaikutuksen käytännöissä on paljon kehitettävää siitäkin huolimatta, että tieteellistä keskustelua vuorovaikutteisesta suunnittelusta on käyty jo vuosikymmeniä (ks. mm. Healey, 1992 ja Innes ja Booher 2004). Tässä diplomityössä on pyritty kehittämään käytännönläheisiä ratkaisuja suunnitteluprosessien vuorovaikutusta koskeviin ongelmiin erityisesti Staffans (ym. 2020) kuvaaman prosessisensitiivisen lähestymistavan avulla. Prosessisensitiivisessä lähestymistavassa osallistieto nähdään yhtenä suunnittelun tietopohjan osana, jota kerätään ja käsitellään vuorovaikutteisesti tarpeen mukaan suunnitteluprosessin eri vaiheissa erilaisia vuorovaikutusta tukevia menetelmiä ja digitaalisia työkaluja hyödyntäen. Tässä diplomityössä prosessisensitiivistä lähestymistapaa on kehitetty osana Espoon Viiskorpi-Kalajärven maankäytön tarkastelun ja Viiskorven kaavarungon oikeusvaikutuksettomia suunnitteluprosesseja. Näiden suunnitteluprosessien aikana kehitetty lähestymistapa, vuorovaikutuksen jatkumo, kuvaa osallistiedon rakentumista, virtaamista ja hyödyntämistä suunnitteluprosessin eri vaiheissa sekä eri suunnitteluprosessien välillä. Diplomityössä tutkitaan toimintatutkimuksen ja haastatteluiden kautta suunnittelijoiden kokemuksia vuorovaikutuksen jatkumon vuorovaikutukseen, kertyneeseen osallistietoon ja sen hyödyntämiseen suunnitteluprosessissa. Lisäksi työssä tarkastellaan, miten erilaiset vuorovaikutusmenetelmät toimivat jatkumon osana. Työn johtopäätöksenä on, että käsittelemällä vuorovaikutusta jatkumona voidaan edistää suunnittelun näkökulmasta oleellisen osallistiedon kertymistä vuorovaikutuksessa sekä helpottaa osallistiedon hyödyntämistä suunnittelussa. Vuorovaikutuksen jatkumon avulla voidaan lisäksi ehkäistä sitä, että vuorovaikutusprosessi tuloksineen jäisi suunnittelusta irralliseksi osaksi, mikä voi edistää osallisten ja suunnittelijoiden välisen luottamuksen rakentumista.
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    System-theoretic process analysis for security in the framework of the international ship and port facility security code
    (2024-01-22) Poutala, Tero; Valdez Banda, Osiris; Basnet, Sunil; Insinööritieteiden korkeakoulu; Roncoli, Claudio
    Maritime security includes preventive measures intended to protect port facilities and ships against threats of intentional unlawful acts. These measures are essential part of contemporary activities of shipping, ports, administrations, as well as a great number of seafarers and other maritime professionals. Contemporary legal regime governing maritime security is the Safety of Life at Sea (SOLAS) Convention Chapter XI-2 on Special Measures to Enhance Maritime Security and the International Ship and Port facility Security (ISPS) Code. This thesis demonstrates how to enhance understanding about maritime security governance by using the System-Theoretic Process Analysis for Security (STPA-SEC) method. Ultimately, this thesis provides a novel application of the method in the framework of the ISPS Code and in the Finnish context. This study defines losses, hazards and constraints in the maritime security context and submits a model for hierarchical ISPS Code based control structure, which includes the interactions of controllers, processes, and controlled processes. With a rigorous application of the STPA-SEC, this study identifies unsecure control actions and loss scenarios. The enhancement and the verification of the model are done through a workshop and interviews with maritime security experts. The research results suggest that the STPA-SEC is a suitable and comprehensive security hazard analysis method in order to systematically model the ISPS requirements, covering holistically both ship and port facility aspects. STPA-SEC is found to be an effective method in order to identify loss scenarios, with results that have practical significance for ship and port owners as well as respective security actors to adapt and maintain security functions align with the maritime security requirements.
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    Päivittäispalaverien soveltuvuus ja vaikutukset rakennesuunnitteluprosessien hallintaan
    (2024-01-22) Särkilahti, Joonas; Högman, Tom; Insinööritieteiden korkeakoulu; Seppänen, Olli
    Rakennusalan suunnitteluorganisaatiot voivat lisätä tuottavuutta kehittämällä prosessiensa hallintaa. Rakennesuunnitteluprosessien hallinnan kehittämisessä avainasemassa on esimerkiksi sisäiseen kommunikaation ja tiedonkulkuun sekä prosessin seurantaan liittyvien haasteiden lieventäminen. Monilla muilla aloilla tässä on onnistuttu hyödyntämällä Lean-filosofian mukaista päivittäisjohtamista, joka koostuu monista eri työkaluista ja käytännöistä, kuten päivittäispalavereista. Päivittäispalaverien vaikutuksia on alettu tutkimaan enemmän myös rakennusalalla, ja vaikka monista tutkimuksista onkin saatu lupaavia tuloksia, ei aihetta kuitenkaan olla vielä juurikaan tutkittu rakennusalan suunnitteluprosessien kontekstissa. Tutkimuksen tavoitteena oli selvittää päivittäispalaverien soveltuvuutta ja vaikutuksia rakennesuunnitteluprosessien hallintaan. Tutkimuksessa kehitettiin kohdeyrityksen rakennesuunnittelun yksikköön soveltuva viitekehys, joka lisää ymmärrystä aiheeseen ja siihen kuuluviin ilmiöihin liittyen, mikä mahdollistaa päivittäispalaverikäytännön laajemman hyödyntämisen. Tutkimuksessa myös luotiin ja kehitettiin kohdeyrityksen käyttöön tarvittavat työkalut uuden käytännön tehokasta implementointia ja hyödyntämistä varten. Samalla tutkimuksen avulla pyrittiin tuottamaan alalle uutta tietoa päivittäispalaverien vaikutuksiin liittyen, ja lieventämään näin aiheen huomattavaa tutkimusvajetta. Diplomityö toteutettiin kahdessa syklissä hyödyntäen suunnittelututkimuslähestymistapaa. Ensimmäisen syklin aikana luotiin kirjallisuuskatsauksen sekä kohdeyrityksen toiminnan diagnosoinnin perusteella rakennesuunnittelun kontekstiin sopiva, kolmiosainen artefakti. Toisessa syklissä arvioitiin testausprosessin avulla artefaktin käytännön toimivuutta ja soveltuvuutta. Arvioinnin perusteella artefaktin osia kehitettiin paremmin kohdeyrityksen prosesseihin ja tarpeisiin soveltuviksi. Tutkimuksen perusteella päivittäispalaverien implementoinnin avulla voidaan kehittää rakennesuunnitteluprosessien hallintaa merkittävästi. Palaverikäytäntö mahdollistaa tehokkaamman sisäisen kommunikaation ja prosessin seurannan, mikä kehittää esimerkiksi tiedonkulkua ja esteiden tunnistamista sekä myös lisää tekijöiden välistä luottamusta. Lisäksi kehittyy tekijöiden kyky suunnitella ja arvioida omia töitä ja tehtävien toteutusta. Päivittäispalaverikäytännön avulla voidaan myös rauhoittaa projektipäälliköiden päivittäistä työtä sekä helpottaa projektien resurssointia ja aikatauluttamista.Tutkimus osoitti, että palaverikäytäntö helpottaa prosessin hallintaa etenkin suurempien projektitiimien kanssa, mutta niistä voidaan kuitenkin hyötyä kaikissa rakennesuunnitteluprojekteissa.
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    3D geological modelling and pattern recognition – Case study Sakatti
    (2024-01-22) Kivisaari, Tiia; Lamberg, Pertti; Insinööritieteiden korkeakoulu; Rönnholm, Petri
    3D geological modelling has become a fundamental activity in geosciences and engineering to visualise and represent subsurface formations. A geological model is a computer representation of the geological subsurface for a specific area of interest that describes geological volumes such as rock types and structures. The boundaries between geological volumes are based largely on categorical, e.g. lithological logging data, and numerical borehole data, e.g. geochemical analysis data. The use of geochemical data can provide non-subjective information for modelling. Volume boundary definition is too often performed in single variable mode, even though modelling could be supported by multivariate data analysis. In this case study of the Sakatti deposit, the goal was to use multivariate statistical analysis to identify possible beneficial relationships between variables and in uncovering new patterns to support future 3D modelling. Such analyses are quantitative and independent approaches. This study was based on the Sakatti Geology and mineralization 3D Model Update 2020 and the data contained therein. Multi-variate statistical analysis of a 13-part subcompositional geochemical dataset (26445 samples) was performed. Multivariate analyses included hierarchical clustering, principal component analysis, and k-means clustering. The multivariate analysis methods used showed relatively good results and provided usable information that can be used in geological modelling. However, the results were not comprehensive due to the limited subcompositional data available. Hierarchical cluster analysis was an efficient technique to identify compositional dependencies between the variables used, and principal component analysis provided multi-element PC scores that could be used as an alternative source of information in assessing geochemical variations and defining volume boundaries. K-means clustering did not extract geologically significant groups, i.e. for the elements used, the geochemical contrast was not high enough to obtain enough distinct clusters. Further studies using principal component analysis and k-means clustering could be combined with careful consideration of which variables are needed for the classification and interpretation of the rock types.
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    Mechanical properties of recycled materials in non-load bearing wall structure
    (2024-01-22) Luoma, Anssi; Gustavsson, Henry; Insinööritieteiden korkeakoulu; Korkiala-Tanttu, Leena
    The use of recycled materials is the key component of sustainable development in the construction industry. This study examines the suitability of recycled materials obtained from the Turku region for non-load bearing wall structure using both rammed earth and casting methods. The traditional method of rammed earth involves methodically compacting damp natural soil inside a mould. The mould may be removed immediately after compacting the soil, leaving behind well-structured compacted earth. Casting technique was specifically studied focusing on precast interlocking concrete blocks. With these it is possible to create interlocking blocks that allow convenient and efficient construction. Using both techniques, the objective was to create an environmentally friendly construction material from recycled materials. The compressive strength is the most important property for both construction methods and the created construction material. The materials used as binders in this research were bio-based fly ash and bottom ash, blast furnace slag and CEM III/B. Crushed concrete and quarry fines have been used as aggregates. Nominal quantities of cement have been utilized solely as an activator in the masses, constituting between 3,33-5,00% by weight of the dry mass. Laboratory tests were conducted to assess the properties and suitability of recycled materials for specific construction methods. The study focused on the compressive strength of the materials, employing ultrasonic pulse velocity and unconfined compression tests. Freeze-thaw cycles were also examined for their impact on material properties. Six samples were tested for each set, with three undergoing freeze-thaw cycles and three undergoing immediate unconfined compression testing. The rammed earth method exhibited higher compressive strengths compared to the casting technique when utilizing recycled materials. After 28 days of curing, rammed earth samples achieved 3,1-18,1 MPa compressive strengths, while casting method samples varied from 0,8-11,2 MPa. Freeze-thaw cycles had minimal impact on rammed earth samples, and using Stora Enso fly ash as a binder increased the maximum compressive strength after freeze-thaw cycles. Conversely, casting method samples experienced an average 37% decrease in compressive strength when exposed to freeze-thaw cycles. Using recycled materials, both precast and rammed earth methods are best suited to simple, non-load bearing structures that do not require high structural properties such as high compressive, tensile or shear strength. The main advantage of using recycled materials is the low carbon footprint compared to for example using traditional concrete.
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    The current and future digital participation methods in urban planning in Finnish municipalities
    (2024-01-22) Kaskela, Eetu; Nummi, Pilvi; Insinööritieteiden korkeakoulu; Kyttä, Marketta
    EParticipation is participation method which is implemented partially or fully with the use of information and communication technologies.This study was implemented to find out how the use of eParticipation methods have changed after the COVID-19 pandemic. The purpose of this research was to study how Finnish municipalities are using eParticipation methods in their participation process in urban planning. This research tried to find what eParticipation tools Finnish municipalities are using and how they are using them. This research tried to find out how COVID-19 pandemic changed the participation practises in Finnish municipalities and how Finnish municipalities see eParticipation in the future. This research was implemented with open online survey and semi-structured interviews as methods. Open online survey was made by the department of built environment at Aalto university. This open online survey was addressed to all those working on the field of land use planning, regardless of the organization. Semi-structured interviews were organised for getting deeper knowledge on the planners’ feelings towards eParticipation in urban planning and to complement the answers from the online survey. Two semi-structured interviews were held which included total of five planners. According to online survey and semi-structured interviews most of the Finnish municipalities are using eParticipation methods in their participation processes in urban planning. Main purpose of using eParticipation methods is to collect data and opinions from citizens before planning project. The most used eParticipation tools for collecting data and opinions from citizens are websites, electric feedback system, social media, and online meetings. Main challenge for Finnish municipalities with eParticipation is the lack of recourses for introducing new eParticipation methods into participation process. Lack of recourses also prevent possibility of training for planners to know how to use new eParticipation methods. This research found out that eParticipation methods and traditional participation methods are both key elements for participation process in the future and improving them to work together is the main challenge in the future. To be able to have eParticipation and traditional participation working together, eParticipation tools should be developed so that interaction in them would increase and they could be used side by side simultaneously with traditional participation.
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    Non-destructive evaluation of glued laminated timber beams
    (2024-01-22) Lu, Yu-Hsuan; Fink, Gerhard; Insinööritieteiden korkeakoulu; Fink, Gerhard
    This study aims to contribute to the non-destructive investigations of glued laminated timber (GLT) beams that emphasize on the evaluation of strength grade, simplifying assessment procedures and identifying members with properties that are expected to be significantly different to the majority. Inspired by the strength grading methods of timber boards, which are visual strength grading and machine grading, 21 GLT beams are first visual inspected and vibration tests are performed after. Single knot width, annual ring width and the existence of pith are documented whereas the measurements of knots are from image processing in Matlab and the other characteristics are observed manually. In vibration tests, vibrating direction, the effects of support stiffness and loading status are investigated. Leveraging the results from above non-destructive indicators, the aims of the study are achieved by identifying the lay up of GLT beams, excluding impossible grade options and detecting members of properties that are expected to be significantly different to the majority by comparing the cumulative density function of the measurements. Assessment procedures are suggested to be simplified by ignoring finger joint location when visual grading GLT beams and performing vibration test in flexural direction before GLT members are disassembled.
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    Green commercial real estate debt financing and market practices
    (2024-01-22) Jalo, Anna-Mari; Saari, Anniina; Insinööritieteiden korkeakoulu; Falkenbach, Heidi
    This study examines the drivers and barriers of commercial green real estate debt financing and the market practices of commercial green real estate loans. This study aims to increase understanding of the influencing factors behind green real estate financing and provide information on current market practices. In this study, green real estate debt financing refers to the financing of existing real estate and construction that can be classified as green as well as green transition investment financing. This study was conducted as qualitative research including a literature review and an empirical qualitative part, which was conducted in seven interviews with the largest banks that provide loans for professional real estate investors and operate in Finland. The findings of the study show that several drivers and barriers are influencing commercial green real estate financing. The main drivers are greenium, increased awareness, development of technology and criteria, strong collaboration among stakeholders and a favorable macroeconomic environment. The main barriers are confusion on what can be classified as green buildings for green finance, limited knowledge on benefits of green finance, lack of common practices and criteria, high borrowing charges related to green certification valuation costs, lack of assets eligible for green financing, limited measures to raise and promote green finance and lack of incentives and splitting incentives. Regulation was identified as both a driver and a barrier. In addition, the findings of the study present that the market practices of commercial green real estate loans vary somewhat depending on the loan provider, especially related to the criteria and greenium. Overall, several drivers and barriers are influencing green real estate financing demand, supply and pricing. Regulation is believed to be the solution to several barriers and thus to develop green real estate finance in general as well as market practices of commercial green real estate loans. Moreover, the availability of financing and refinancing, in general, is seen as more meaningful than the significance of the greenium in the future.
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    Optimization of the stacking sequence for maximization of the eigen frequency of composite structures.
    (2024-01-22) Shabbir, Jamal; Vuorio, Jaakko; Insinööritieteiden korkeakoulu; Romanoff, Jani
    Carbon fiber composites, particularly unidirectional and woven forms, play a vital role in various structural applications. While extensive research exists on optimizing the stiffness and eigen frequencies of basic structures like plates, cylinders, and cones, there is a noticeable gap in literature concerning the optimization of complex composite structures, such as drone frames. The eigen frequency and dynamic response of a structure are influenced by factors like boundary conditions, geometric parameters (thickness, aspect ratio, shape), and the dynamic environment it operates in. In this study, optimization efforts have focused on thin composite plates and cylinders. Analytical and numerical methods based on classical lamination theory and first-order shear deformation theory were employed to derive the stiffness matrices, followed by optimization using genetic algorithms (GAs) with the objective of finding the stack sequence that maximizes the first mode frequency. GAs, inspired by natural selection, excel in navigating complex, non-convex design spaces and are well-suited for problems involving poorly understood or nonlinear objective functions. The choice of GA for optimizing drone frames is motivated by its ability to efficiently explore large design spaces and find optimal combinations that might be elusive through other means. The focus of the optimization is to ensure that none of the drone's eigen frequencies fall within critical operational ranges, particularly during hover, where blade passage frequency is a prominent forcing frequency. The research methodology involved identifying problematic frequencies through bench and flight tests, constructing a mathematical model in Ansys ACP, and validating it by comparing numerical and real drone frame modes. Subsequently, the validated model underwent optimization using GA. Key outcomes of the study include the observation that boundary conditions significantly affect both the eigen frequency and the convergence rate of optimization. Additionally, while higher-order deformation theories provide more accurate predictions, computational costs can be prohibitive. Therefore, choosing an appropriate theory should be based on the structure's geometry. For instance, classical lamination theory is effective for thin-walled structures, providing reasonably accurate results while potentially overestimating stiffness for moderately thick to thick-walled structures. Lastly, the study found that symmetric laminates generally exhibit higher stiffness compared to asymmetric laminates. This research contributes valuable insights into the optimization of complex composite structures, specifically drone frames, using a combination of analytical, numerical, and evolutionary methods.
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    Structural stress assessment for butt-welded thin plates
    (2024-01-22) Sandgren, Jani; Mancini, Federica; Lehto, Pauli; Insinööritieteiden korkeakoulu; Remes, Heikki
    In order to reduce the environmental and economic impact of shipbuilding, the development of energy-efficient lightweight ship structures has been a research focus in the last decades. Ships are mainly constructed of welded plates with a minimum thickness of 5-mm, due to limitations in current shipbuilding design codes and fatigue assessment recommendations. In order to enable the use of thinner plates, a general improvement in the structural assessment practices is needed. The present thesis focuses on the experimental and analytical structural hot-spot stress assessment of 4-mm butt-welded thin and slender plates with a curved welding-induced distortion made of S355 steel. Monotonic tensile test is used to validate an analytical model for the estimation of the stress magnification factor (km) due to axial and angular misalignment. The analytical model uses the Euler-Bernoulli beam theory extended to moderate rotations under either pinned or fixed boundary conditions and in its linear-elastic range. Differently from the model currently recommended by the International Institute of Welding (IIW), the one under validation also considers the local angular misalignment due to a half-sine shape of the distortion. The experimental study included the measurement of the geometry via structured light 3D scanning, in addition to strain gauge measurements under varying load level. The suitability of Digital Image Correla-tion (DIC) for the strain measurements in the context of structural hot-spot stress assessment was also addressed. Linear and quadratic extrapolations for the computation of the km factor were conducted as indicated by the IIW. It was found that the km values obtained using the improved model are close to the experimental data and more accurate than the ones based on the current IIW recommendation. The average error percentage for the improved formulation was 4 – 6 %, with a maximum of 14 %, when describing the curvature by its maximum amplitude and assuming fixed boundary conditions. These results were obtained after careful application of the extrapolation method due to unexpected behaviour of strains on the surface of the material, possibly caused by the undercut near the weld. Thus, further research is required to assess the suitability of the extrapolation procedures indicated in the current recommendations for plates thinner than 5 mm.
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    The investment feasibility of rental row housing - A Finnish case study
    (2024-01-22) Lindroos, Rickard; Falkenbach, Heidi; Insinööritieteiden korkeakoulu; Falkenbach, Heidi
    The thesis is done in collaboration with a private equity real estate company who have been presented with the opportunity to invest in portfolio of rental row houses and semi-detached buildings to be developed. To make a well-informed investment decision, all investment opportunities must be subject of a feasibility analysis. However, the scarcity of comparable investments raises the question of the asset class’s viability within the broader Finnish real estate asset market. That is, will investors’ objectives be met if they invested in rental row houses and demi-detached buildings? To research the question, the concept of feasibility is examined through a literature study together with fundamental elements associated with real estate investment and development. The literature findings are combined to a feasibility analysis framework aimed at re-solving the challenge of scarce market rent data for this specific asset type. The empirical part of the thesis is conducted as a case study where the proposed investment is analysed for feasibility using the aforementioned framework. The analysis included interviews with several market experts both within and outside the case company to evaluate the investment in its market context. The literature study concluded that feasibility depends on the fit and probability of an investment meeting the investor’s objectives despite inherent limitations and constraints. Moreover, a framework for conducting investment feasibility analysis for markets with limited rental data is developed, building on previous research in the subject. The case study's findings suggest that the proposed investment opportunity is feasible for the investor, assuming prevailing market conditions, costs, and terms for the investment. This outcome implies that similar portfolio developments could also be feasible, thereby suggesting viability for rental row houses and semi-detached buildings in the Finnish asset market. However, a more detailed analysis of the proposed investment plans is necessary to draw a final investment decision. The absence of detailed project information weakens the conclusion regarding general feasibility, emphasizing the need for further research on the topic.
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    Laadunvarmistus tahtituotannossa
    (2024-01-22) Väisänen, Eero; Riekki, Jaakko; Insinööritieteiden korkeakoulu; Seppänen, Olli
    Rakennustuotannon tuottavuuden kehitys on ollut haasteellista ja alalle on pyritty tuomaan ja kehittämään uudenlaisia toimintatapoja. Tuottavuuden lisäksi myös hyväksyttävän laadun tuottaminen on pitkäaikainen rakennusalan ongelma. Tahtituotanto on viime aikoina paljon esillä ollut ja nousevassa trendissä oleva tuotantoprosessi, jolla toivotaan olevan vaikutuksia moniin rakennusalalle juurtuneisiin ongelmiin. Uusiin tuotantomenetelmiin ja erityisesti tahtituotantoon liittyen on tehty paljon tutkimuksia, mutta näissä on keskitytty usein tahtituotannon suunnitteluun, soveltamiseen ja toteuttamiseen. Tutkimuksia laadunhallinnan metodeista tai toteutuksesta tahtituotannon yhteydessä ei juurikaan löydy. Diplomityössä tarkasteltiin laatua käsitteenä ja laadunhallinnan kehitystä rakennussalalla sekä erilaisten työmaan päätösten vaikutusta laatuun. Tutkimuksen tavoitteena oli selvittää tahtituotannon aiheuttamia vaikutuksia tuotantoprosessiin, laadunvarmistukseen sekä lopputuotteen laatuun. Tutkimus pitää sisällään kirjallisen ja empiirisen osuuden. Empiirinen osuus toteutettiin tapaustutkimuksena, jossa tutkittiin yhden hankkeen työntekijöiden kokemuksia tahtituotannosta ja laadunvarmistuksesta. Haastatteluiden avulla pyrittiin saamaan yleiskuva hankkeen eri organisaatioiden kokemuksista tuotantomenetelmän toimivuudesta sekä haasteista. Tutkimuksessa saadut tulokset saavat tukea kirjallisuudesta. Tahtituotannon käyttö parantaa tuotantojärjestelmää ja mahdollistaa laadukkaan tuotannon toteuttamisen. Laadunhallinnan järjestäminen osana tahtituotantoa vaatii kuitenkin uudenlaista ennakointia, järjestelmällisyyttä ja sitoutumista unohtamatta yhteistyötä ja toimivaa kommunikointia. Uudenlaiset menetelmät vaativat myös asennemuutosta aikataulutuksen ja resurssoinnin suhteen. Laatua korostava ja uudenlaiset prosessit hyväksyvä yhteistoiminnallinen kulttuuri vaatii aikaa muodostuakseen, koska avainhenkilöiden aiemmat kokemukset vaikuttavat sitoutumisen tasoon. Jatkotutkimuksissa tulisi perehtyä tahtituotannon konkreettisiin laatuvaikutuksiin sekä seurantaa tehostaviin sähköisiin työkaluihin.
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    Techno-economic analysis of battery energy storage systems for grid congestion management and offshore wind parks
    (2024-01-22) Abrego Soderberg, Rodrigo; Grbovic, Olga; Rubenbauer, Hubert; Insinööritieteiden korkeakoulu; Santasalo-Aarnio, Annukka
    In the accelerated transition to a sustainably powered economy, offshore wind has increasingly become a strong focus in several nations as they offer vast generation potential with minimal conflict for a relatively limited land area. In Europe, Germany and Finland are among the top promoters for exploiting this clean resource, both sharing the Baltic Sea region. This investigation analyses the offshore wind expansion plans in Finland and Germany’s Baltic coast, and discovers a potential location for a BESS to be installed in conjunction with existing and future generation to provide services to the grid such as Grid Congestion Management for offshore generation, along with a simplified energy arbitrage algorithm, and evaluates their business potential through the construction of a Free Cash Flow model that ties together revenue and cost modelling, use-case-dependent degradation modelling and an alternate iterative sizing methodology for BESS. It is discovered that the business potential of such a BESS depends significantly on the energy market conditions and its price volatility, but by combining both an opportunistic curtailment capture algorithm with an energy arbitrage algorithm as operating regime, synergies can be achieved which strengthen the Internal Rate of Return of a 20-year project such as the proposed system.