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  • 1.
    Azzi, Elias Sebastian
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Karltun, E.
    Sundberg, Cecilia
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Small-scale biochar production on Swedish farms: A model for estimating potential, variability, and environmental performance2021In: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 280, article id 124873Article in journal (Refereed)
    Abstract [en]

    Several small-scale pyrolysis plants have been installed on Swedish farms and uptake is increasing in the Nordic countries. Pyrolysis plants convert biomass to biochar for agricultural applications and syngas for heating applications. These projects are driven by ambitions of achieving carbon dioxide removal, reducing environmental impacts, and improving farm finances and resilience. Before policy support for on-farm pyrolysis projects is implemented, a comprehensive environmental evaluation of these systems is needed. Here, a model was developed to jointly: (i) simulate operation of on-farm energy systems equipped with pyrolysis units; (ii) estimate biochar production potential and its variability under different energy demand situations and designs; and (iii) calculate life cycle environmental impacts. The model was applied to a case study farm in Sweden. The farm's heating system achieved net carbon dioxide removal through biochar carbon sequestration, but increased its impact in several other environmental categories, mainly due to increased biomass throughput. Proper dimensioning of heat-constrained systems is key to ensure optimal biochar production, as biochar production potential of the case farm was reduced under expected climate change in Sweden. To improve the environmental footprint of future biochar systems, it is crucial that expected co-benefits from biochar use in agriculture are realised. The model developed here is available for application to other cases.

  • 2.
    Azzi, Elias Sebastian
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Karltun, Erik
    Swedish Univ Agr Sci SLU, Dept Soil & Environm, Uppsala, Sweden..
    Sundberg, Cecilia
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure. Department of Energy and Technology, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden.
    Assessing the diverse environmental effects of biochar systems: An evaluation framework2021In: Journal of Environmental Management, ISSN 0301-4797, E-ISSN 1095-8630, Vol. 286, article id 112154Article in journal (Refereed)
    Abstract [en]

    Biochar has been recognised as a carbon dioxide removal (CDR) technology. Unlike other CDR technologies, biochar is expected to deliver various valuable effects in e.g. agriculture, animal husbandry, industrial processes, remediation activities and waste management. The diversity of biochar side effects to CDR makes the systematic environmental assessment of biochar projects challenging, and to date, there is no common framework for evaluating them. Our aim is to bridge the methodology gap for evaluating biochar systems from a life-cycle perspective. Using life cycle theory, actual biochar projects, and reviews of biochar research, we propose a general description of biochar systems, an overview of biochar effects, and an evaluation framework for biochar effects. The evaluation framework was applied to a case study, the Stockholm Biochar Project. In the framework, biochar effects are classified according to life cycle stage and life cycle effect type; and the biochar?s end-of-life and the reference situations are made explicit. Three types of effects are easily included in life cycle theory: changes in biosphere exchanges, technosphere inputs, and technosphere outputs. For other effects, analysing the cause-effect chain may be helpful. Several biochar effects in agroecosystems can be modelled as future productivity increases against a reference situation. In practice, the complexity of agroecosystems can be bypassed by using empirical models. Existing biochar life cycle studies are often limited to carbon footprint calculations and quantify a limited amount of biochar effects, mainly carbon sequestration, energy displacements and fertiliser-related emissions. The methodological development in this study can be of benefit to the biochar and CDR research communities, as well as decision-makers in biochar practice and policy.

  • 3.
    Azzi, Elias Sebastian
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Karltun, Erik
    Swedish Univ Agr Sci SLU, Dept Soil & Environm, Uppsala, Sweden..
    Sundberg, Cecilia
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure. Swedish Univ Agr Sci SLU, Dept Energy & Technol, Uppsala, Sweden..
    Life cycle assessment of urban uses of biochar and case study in Uppsala, Sweden2022In: Biochar, ISSN 2524-7972, E-ISSN 2524-7867, Vol. 4, no 1, article id 18Article in journal (Refereed)
    Abstract [en]

    Biochar is a material derived from biomass pyrolysis that is used in urban applications. The environmental impacts of new biochar products have however not been assessed. Here, the life cycle assessments of 5 biochar products (tree planting, green roofs, landscaping soil, charcrete, and biofilm carrier) were performed for 7 biochar supply-chains in 2 energy contexts. The biochar products were benchmarked against reference products and oxidative use of biochar for steel production. Biochar demand was then estimated, using dynamic material flow analysis, for a new city district in Uppsala, Sweden. In a decarbonised energy system and with high biochar stability, all biochar products showed better climate performance than the reference products, and most applications outperformed biomass use for decarbonising steel production. The climate benefits of using biochar ranged from - 1.4 to - 0.11 tonne CO2-eq tonne(-1) biochar in a decarbonised energy system. In other environmental impact categories, biochar products had either higher or lower impacts than the reference products, depending on biochar supply chain and material substituted, with trade-offs between sectors and impact categories. However, several use-phase effects of biochar were not included in the assessment due to knowledge limitations. In Uppsala's new district, estimated biochar demand was around 1700 m(3) year(-1) during the 25 years of construction. By 2100, 23% of this biochar accumulated in landfill, raising questions about end-of-life management of biochar-containing products. Overall, in a post-fossil economy, biochar can be a carbon dioxide removal technology with benefits, but biochar applications must be designed to maximise co-benefits.

  • 4.
    Bin Ashraf, Faisal
    et al.
    Univ Oulu, Water Resources & Environm Engn Res Unit, POB 4300, Oulu 90014, Finland..
    Haghighi, Ali Torabi
    Univ Oulu, Water Resources & Environm Engn Res Unit, POB 4300, Oulu 90014, Finland..
    Riml, Joakim
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Alfredsen, Knut
    Norwegian Univ Sci & Technol NTNU Vassbygget, 442 Valgrinda, Trondheim, Norway..
    Koskela, Jarkko J.
    Finnish Environm Inst SYKE, Mechelininkatu 34a,POB 140, Helsinki 00260, Finland..
    Klove, Bjorn
    Univ Oulu, Water Resources & Environm Engn Res Unit, POB 4300, Oulu 90014, Finland..
    Marttila, Hannu
    Univ Oulu, Water Resources & Environm Engn Res Unit, POB 4300, Oulu 90014, Finland..
    Changes in short term river flow regulation and hydropeaking in Nordic rivers2018In: Scientific Reports, E-ISSN 2045-2322, Vol. 8, article id 17232Article in journal (Refereed)
    Abstract [en]

    Quantifying short-term changes in river flow is important in understanding the environmental impacts of hydropower generation. Energy markets can change rapidly and energy demand fluctuates at sub-daily scales, which may cause corresponding changes in regulated river flow (hydropeaking). Due to increasing use of renewable energy, in future hydropower will play a greater role as a load balancing power source. This may increase current hydropeaking levels in Nordic river systems, creating challenges in maintaining a healthy ecological status. This study examined driving forces for hydropeaking in Nordic rivers using extensive datasets from 150 sites with hourly time step river discharge data. It also investigated the influence of increased wind power production on hydropeaking. The data revealed that hydropeaking is at high levels in the Nordic rivers and have seen an increase over the last decade and especially over the past few years. These results indicate that increased building for renewable energy may increase hydropeaking in Nordic rivers.

  • 5.
    Bin Ashraf, Faisal
    et al.
    Univ Oulu, Water Energy & Environm Engn Res, Oulu, Finland..
    Haghighi, Ali Torabi
    Univ Oulu, Water Energy & Environm Engn Res, Oulu, Finland..
    Riml, Joakim
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Kondolf, G. Mathias
    Univ Calif Berkeley, Dept Landscape Architecture & Environm Planning, Berkeley, CA 94720 USA..
    Klove, Bjorn
    Univ Oulu, Water Energy & Environm Engn Res, Oulu, Finland..
    Marttila, Hannu
    Univ Oulu, Water Energy & Environm Engn Res, Oulu, Finland..
    A Method for Assessment of Sub-Daily Flow Alterations Using Wavelet Analysis for Regulated Rivers2022In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 58, no 1, article id e2021WR030421Article in journal (Refereed)
    Abstract [en]

    New tools are needed to evaluate the impacts of short-term hydropower regulation practices on downstream river systems and to progress towards sustainable river-flow management. As hydropower is increasingly being used to balance the energy load deficit caused by other less flexible sources, sub-daily flow conditions across many regulated river (RR) systems are changing. To address this, we used wavelet analyses to quantify the discharge variability in RRs and categorized the level of variability based on the conditions in natural free-flowing rivers. The presented framework used the definition of fluvial connectivity (Grill et al., 2019) to identify free-flowing rivers used in the study. We tested the developed framework in 12 different RRs in Finland and found higher overall averaged sub-daily variations, with up to 20 times larger variability than natural conditions. A large, highly regulated Finnish river system was found to have the highest sub-daily variations in winter, while smaller RRs with lower levels of regulation the highest variations in summer. The proposed framework offers a novel tool for sustainable river management and can be easily applied to various rivers and regions globally. It had flexibility to analyze sub-daily variations in desired seasonal or other ecologically sensitive periods.

  • 6. Bo, Li
    et al.
    Xiao-feng, Cui
    Yang-yang, Mo
    Zou, Liangchao
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Fa-quan, Wu
    Deformation behavior of disclosed sandstone fractures subjects to normal stresses2021In: Robotics and Biomimetics, ISSN 1000-7598, E-ISSN 2197-3768, Vol. 42, no 7, p. 1850-1860Article in journal (Refereed)
    Abstract [en]

    Subject to geological processes, natural rock fractures can be dislocated to some extent, and the normal deformation behavior of such dislocated fractures has not been quantitatively estimated, and the applicability of classic deformation models has not been verified against experiments and numerical simulations. The deformation and failure behavior of dislocated sandstone fractures were studied via compression tests and elastic-plastic contact simulations. The obtained stress-displacement curves were fitted by a hyperbolic model, an exponential model and a logarithmic model, respectively and the coefficients involved in these models were estimated. The results show that the experimentally and numerically obtained stress-displacement curves agree well with each other, and the surface damage areas are also consistent, which verified the reliability of the elastic-plastic contact model. The hyperbolic and logarithmic models do not fit the curves well under relatively low stress levels, while the exponential model well accommodates the simulation results in the whole loading process by introducing a coefficient n. The maximum closure V-max. is positively correlated with the maximum local aperture, the initial normal stiffness K-ni is positively correlated with the elastic modulus and negatively correlated with the fracture roughness and dislocating ratio, and n is positively correlated with the fracture roughness and dislocating ratio. A model was established to predict the three coefficients, and the prediction values agree well with the experimental results.

  • 7.
    Brandao, Miguel
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Azzi, Elias Sebastian
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Novaes, Renan.M.L.
    Cowie, Annette
    The modelling approach determines the carbon footprint of biofuels: the role of LCA in informing decision makers in government and industry2021In: Cleaner Environmental Systems, ISSN 2666-7894, Vol. 2, p. 100027-Article in journal (Refereed)
    Abstract [en]

    Concerns over climate change have led to the promotion of biofuels for transport, particularly biodiesel from oilseed crops and ethanol from sugar and starch crops. However, the climate-change mitigation potential of the various biofuels estimated in published studies tends to vary significantly, questioning the reliability of the methods used to quantify potential impacts. We investigated the values published in the European Commission’s Renewable Energy Directive (RED), and recalculated the climate-change impacts of a range of biofuels using internally-consistent attributional and consequential modelling approaches to enable comparison of these approaches. We conclude that the estimated results are highly dependent on the modelling approach adopted, to the detriment of the perception of the robustness of life cycle assessment as a tool for estimating the climate-change impacts of biofuels. Land use change emissions are a determining parameter which should not be omitted, even if modelling it introduces a large variability in the results and makes interpretation complex. Clearer guidelines and standardization efforts would be helpful in the harmonization of LCA practice, so that the results can be more useful, robust and reproducible.

  • 8.
    Bukovszki, Viktor
    et al.
    Adv Bldg & Urban Design Ltd, Alkotas Ut 53, H-1123 Budapest, Hungary..
    Dóczi, Gabriella
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Reith, Andras
    Adv Bldg & Urban Design Ltd, Alkotas Ut 53, H-1123 Budapest, Hungary.;Univ Pecs, Res Grp BIM SKILL LAB, H-7624 Pecs, Hungary..
    Coding Engines in Participatory Social Housing Design-A Case to Revisit Pattern Languages2021In: Sustainability, E-ISSN 2071-1050, Vol. 13, no 6, article id 3367Article in journal (Refereed)
    Abstract [en]

    Participation has been touted as a critical instrument for both citizen empowerment and responsibility-sharing in sustainability. In architecture, participation allows for the progression of green building to sustainable habitation that integrates environmental, economic, and social dimensions. However, participation in practice rarely delegates meaningful decisions to marginalized groups and is mostly a one-sided process. This study seeks to investigate which factors of the participatory method afford both empowerment and behavioral change to a sustainable lifestyle in low-income groups. To do so, a case study of designing a social housing estate in Hungary is presented, where participatory design was used to codevelop a building that considers and adjusts to the sustainable lifestyle envisioned by the future residents. A coding engine based on the concept of pattern languages was developed that places conditions and experience of everyday activities at the center of design, translating them to spatial features. As a result, a focus group of social housing tenants and cohousing experts were able to define explicit shared spaces, allocate square meters to them, and articulate legible design criteria. Of the early-stage design decisions, 45% were made with or by the participants, and the bilateral process made it possible to convince the tenants to adopt a more sustainable habitation format.

  • 9.
    Bögel, Paula M.
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure. Karlsruhe Institute of Technology (KIT), Institute for Technology Assessment and Systems Analysis (ITAS), Germany.
    Upham, P.
    Shahrokni, Hossein
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Kordas, Olga
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    What is needed for citizen-centered urban energy transitions: Insights on attitudes towards decentralized energy storage2021In: Energy Policy, ISSN 0301-4215, E-ISSN 1873-6777, Vol. 149, article id 112032Article in journal (Refereed)
    Abstract [en]

    This paper aims to fill a research gap in the area of consumer-citizen attitudes to business models for decentralized energy storage, at the level of households and buildings. The study focuses on the interaction of such attitudes and their underlying motivation factors with socio-cultural, contextual factors. Self-determination theory (SDT) is used as a theoretical framework, to connect interpersonal and contextual factors, addressing the question of how contexts influence the motivation to support energy storage. Drawing on SDT, this study examines the role of autarky (independence from the energy system), autonomy (control over energy management) and relatedness (degree of sharing required) in this regard, embedded and interpreted in the socio-cultural local context of two demonstration sites in Sweden and Portugal. A mixed method approach is used. Quantitative survey data provides information on local social and cultural dimensions, followed by stakeholder consultation workshops that elicit participants’ views on different models of decentralized energy storage. The findings raise questions of how to improve autarky and autonomy for prosumers, while keeping the need for time investment low and provide flexibility regarding the required degree of interaction between prosumers. Implications for business models and policy support for citizen-centered sustainable urban energy systems are derived.

  • 10.
    Cai, Zipan
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Towards a Scenario-based Spatial Dynamic Modeling for Predicting Urban Land Use Change: Planning Tools and Comparative Analysis2023Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    As global urbanization progresses, cities worldwide are growing in size, which leads to many economic, environmental, and management challenges. Recent advancements in spatial data analysis and algorithmic geography have also led to the development of various urban model-based planning support systems (PSS) for urban planning. These PSSs aim to assist urban decision-makers in understanding urban information and collaborating on planning to address urban development challenges. Advanced urban planning concepts are, however, always multidisciplinary, multi-situational, and continuously evolving. In addition to the development of more advanced urban information and communications technology (ICT) and management, planning concepts that promote urban health and sustainable development are needed to meet residents’ physical, spiritual, and social needs, and promote more sustainable lifestyles. These factors create the need for a more rigorous methodological and theoretical foundation to apply PSS to urban planning at the microscale. 

    A scenario-based spatial dynamic modeling approach is proposed in this thesis to address this research gap, allowing for a more precise matching of local policy scenarios and desired development patterns for practical planning support purposes. Several urban development scenarios and their potential impacts are explored by analyzing future urban land use changes. The establishment of this planning support approach effectively integrates spatial analysis, simulation model, policy revision, and participative planning. First, the thesis examines the rules and correlations underlying land unit transformations resulting from human-land interactions in spatial dynamic models by investigating mechanisms driving changes in urban land use. Second, a series of possible urban development simulations are generated through several case studies that employ a variety of representative cities with different urban contexts as model test sites including Nanjing in China, Stockholm in Sweden, and Chicago in the USA to evaluate their validity and practicality. Socioeconomics, ecological systems, and urban amenities are among the research themes that provide a more realistic and practical view of urban development. Last, visualization of the simulation results and quantitative information analyses and transformation is utilized to arrive at recommendations for revising planning policies and promoting sustainable development strategies.

    The challenge of adapting successful experiences of urban transformation from one city to another is considerable and cannot be achieved by merely replicating single projects or developments. An important goal was to address this challenge by developing general methods for model-assisted planning and then exploring their applicability and scalability across different contexts and geographical regions. Obtained results confirm that prioritizing industrial and transportation sectors in urban development is the most significant factor contributing to the rapid expansion of cities. This allocation of resources leads to the development of supporting infrastructure and employment opportunities, thereby attracting more people and industries to urban areas. Limiting the expansion of built-up areas and preserving green spaces is a desired measure to protect natural assets and the composition of cities and mitigate the negative environmental consequences of urbanization. Moreover, it is found that there are significant differences in the spatial and temporal needs and dependencies of residents in different areas with respect to natural and social amenities, providing a basis for future land development in residential and commercial areas of a city. Based on these findings, policymakers can more readily test and evaluate “what-if” scenarios using a process-based approach to avoid uncontrolled urban growth. In spite of limitations and uncertainties, the tools presented in this thesis are relevant for urban policymakers to enhance stakeholder interaction and consensus building in the decision-making process. This work has demonstrated the methodological steps for the implementation of these tools, as well as the general potential benefits of dynamic modeling for sustainable city planning and development.

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  • 11.
    Cai, Zipan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Page, Jessica
    Stockholm Univ, Dept Phys Geog, S-10691 Stockholm, Sweden..
    How Does ICT Expansion Drive "Smart" Urban Growth?: A Case Study of Nanjing, China2020In: Urban Planning, E-ISSN 2183-7635, Vol. 5, no 1, p. 129-139Article in journal (Refereed)
    Abstract [en]

    In the context of accelerated urbanization, socioeconomic development, and population growth, as well as the rapid advancement of information and communication technology (ICT), urban land is rapidly expanding worldwide. Unplanned urban growth has led to the low utilization efficiency of land resources. Also, ecological and agricultural lands are continuously sacrificed for urban construction, which in the long-term may severely impact the health of citizens in cities. A thorough understanding of the mechanisms and driving forces of a city's urban land use changes, including the influence of ICT development, is therefore crucial to the formation of optimal and feasible urban planning in the new era. Taking Nanjing as a study case, this article attempts to explore the measurable "smart" driving indicators of urban land use change and analyze the tapestry of the relationship between these and urban land use change. Different from the traditional linear regression analysis method of driving force of urban land use change, this study focuses on the interaction relationship and the underlying causal relationship among various "smart" driving factors, so it adopts a fuzzy statistical method, namely the grey relational analysis (GRA). Through the integration of literature research and known effective data, five categories of "smart" indicators have been taken as the primary driving factors: industry and economy, transportation, humanities and science, ICT systems, and environmental management. The results show that these indicators have different impacts on driving urban built-up land growth. Accordingly, optimization possibilities and recommendations for development strategies are proposed to realize a "smarter" development direction in Nanjing. This article confirms the effectiveness of GRA for studies on the driving mechanisms of urban land use change and provides a theoretical basis for the development goals of a smart city.

  • 12.
    Cai, Zipan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Kwak, Yoonshin
    Division of Urban Planning and Landscape Architecture, Gachon University, South Korea.
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Deal, Brian
    Department of Landscape Architecture, The University of Illinois at Urbana-Champaign, IL, USA.
    Mörtberg, Ulla
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Sustainability Assessment and Management.
    Urban spatial dynamic modeling based on urban amenity data to inform smart city planningManuscript (preprint) (Other academic)
    Abstract [en]

    An ideal form of smart city planning would focus on the availability of urban amenities that can meet the basic needs of a residents material life, civil connections, and humanistic spirit. Previous studies have concentrated on analyzing the spatial distribution of urban services, with less attention on their contribution as local urban amenities. In this study, we propose a spatial dynamic modeling approach based on urban amenities using social media data from Google Place API to provide locational information on potential resident interactions. We use a representative region in Europe (Stockholm County, SE) to simulate and project urban development in the region, until 2050. Our circular conceptual framework of spatial information and feedback supports decision-makers in testing possible urban planning scenarios that align with the vision of a smart city. Simulation results reveal the interplay between human-land interactions on a specific spatial-temporal scale, and we analyze scenario outcomes in relation to commercial and residential land uses. Overall, our study provides a new perspective on human-social behavior-driven urban development, through a smart, spatial dynamic model as a planning support system that can enhance accuracy and realism, and ultimately help realize planned development objectives in the region.

  • 13.
    Cai, Zipan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Kwak, Yoonshin
    Division of Urban Planning and Landscape Architecture, Gachon University, South Korea.
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Deal, Brian
    Department of Landscape Architecture, The University of Illinois at Urbana-Champaign, IL, USA.
    Mörtberg, Ulla
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Sustainability Assessment and Management.
    Urban spatial dynamic modeling based on urban amenity data to inform smart city planning2023In: Anthropocene, E-ISSN 2213-3054, Vol. 42, article id 100387Article in journal (Refereed)
    Abstract [en]

    An ideal form of smart city planning would focus on the availability of urban amenities that can meet the basic needs of a resident's material life, civil connections, and humanistic spirit. Previous studies have concentrated on analyzing the spatial distribution of urban services, with less attention on their contribution as local urban amenities. In this study, we propose a spatial dynamic modeling approach based on urban amenities using social media data from Google Place API to provide locational information on potential resident interactions. We use a representative region in Europe (Stockholm County, SE) to simulate and project urban development in the region until 2050. Our circular conceptual framework of spatial information and feedback supports decision-makers in testing possible urban planning scenarios that align with the vision of a smart city. Simulation results reveal the interplay between human-land interactions on a specific spatial-temporal scale, and we analyze scenario outcomes in relation to commercial and residential land uses. Overall, our study provides a new perspective on human-social behavior-driven urban development, through a smart, spatial dynamic model as a planning support system that can enhance realism, and ultimately help realize planned development objectives in the region.

  • 14.
    Cai, Zipan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Page, Jessica
    Stockholm University.
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Urban Ecosystem Vulnerability Assessment of Support Climate‐ResilientCity Development2021In: Urban Planning, E-ISSN 2183-7635, no 3, p. 227-239Article in journal (Refereed)
    Abstract [en]

    Climate change poses a threat to cities. Geospatial information and communication technology (Geo-ICT) assisted planning is increasingly being utilised to foster urban sustainability and adaptability to climate change. To fill the theoretical and practical gaps of urban adaptive planning and Geo-ICT implementation, this article presents an urban ecosystem vulnerability assessment approach using integrated socio-ecological modelling. The application of the Geo-ICT method is demonstrated in a specific case study of climate-resilient city development in Nanjing (China), aiming at helping city decision-makers understand the general geographic data processing and policy revision processes in response to hypothetical future disruptions and pressures on urban social, economic, and environmental systems. Ideally, the conceptual framework of the climate-resilient city transition proposed in this study effectively integrates the geographic data analysis, policy modification, and participatory planning. In the process of model building, we put forward the index system of urban ecosystem vulnerability assessment and use the assessment result as input data for the socio-ecological model. As a result, the model reveals the interaction processes of local land use, economy, and environment, further generating an evolving state of future land use in the studied city. The findings of this study demonstrate that socio-ecological modelling can provide guidance in adjusting the human-land interaction and climate-resilient city development from the perspective of macro policy. The decision support using urban ecosystem vulnerability assessment and quantitative system modelling can be useful for urban development under a variety of environmental change scenarios.

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  • 15.
    Cai, Zipan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Wang, Bo
    Sun Yat-Sen University, China.
    Cong, Cong
    University of Illinois at Urbana, Champaign, IL, USA.
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Spatial dynamic modelling for urban scenario planning: A case study of Nanjing, China2020In: Environment and Planning B: Urban Analytics and City Science, ISSN 2399-8083, Vol. 47, no 8, p. 1380-1396Article in journal (Refereed)
    Abstract [en]

    Although urban scenario planning is widely applied for exploring various directions of urban development, it often has high requirements on the medium of quantitative information analysis and transformation. Thus, this study establishes a method of combining scenario planning with a spatial dynamic planning support system to predict urban growth. Specifically, a scenario-based spatial dynamic modelling method is integrated with the information module of planning policy for better decision support. The integrated modelling method is applied for an actual urban land use planning case of Nanjing, an evolving city in China. The spatial forms of future urban land use are simulated under four different pre-set policy scenarios. The differences in simulated results under multi-criteria restrictions reveal the effectiveness and practical value of the integration approach. The findings of this study provide policymakers with a process-based approach to test and evaluate ‘what-if’ consequences and help stakeholders reach consensus.

  • 16.
    Chen, Chen
    et al.
    KTH. China Univ Geosci, Sch Environm Studies, Hubei Key Lab Yangtze Catchment Environm Aquat Sc, Wuhan 430074, Peoples R China.;Minist Nat Resources, Wuhan Geol Survey Ctr, China Geol Survey, Wuhan 430074, Peoples R China..
    Tao, Quanyu
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems.
    Wen, Zhang
    China Univ Geosci, Sch Environm Studies, Hubei Key Lab Yangtze Catchment Environm Aquat Sc, Wuhan 430074, Peoples R China..
    Wörman, Anders
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Jakada, Hamza
    Baze Univ, Dept Civil Engn, Abuja, Nigeria..
    Step-drawdown test for identifying aquifer and well loss parameters in a partially penetrating well with irregular (non-linear increasing) pumping rates2022In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 614, article id 128652Article in journal (Refereed)
    Abstract [en]

    A step-drawdown test with an increasing pumping rate at each step in a fully penetrating well is a typical procedure for estimating aquifer parameters and well losses. However, partially penetrating wells in closed aquifers have also been adopted mainly due to economic constraints with a stepwise increase in the pumping rate. In this study, a new empirical method is proposed based on the stepwise drawdown defined by irregular pumping rates in a partially penetrating well. The method was validated by fitting drawdown data from classical works. The characteristics of the drawdowns and well losses were discussed for varying pumping scenarios. The results indicate that the new empirical method interprets previous works more accurately for a fully penetrating well and also effectively estimates the aquifer and well loss parameters. A new coefficient, the pumping ratevarying index a, was introduced to indicate the pumping rate difference (Delta Q) between the two steps. As such, a negative pumping rate difference would decrease the well-loss and result in a negative a. In addition, the effect of the ratio of the well's screen length to aquifer thickness demonstrates that a longer screen would cause a larger well loss. Finally, the proposed empirical method was applied to a fieldwork conducted in Xiangyang city, central China, to investigate the aquifer and well loss parameters using the particle swarm optimization (PSO) method.

  • 17.
    Chen, Guangfu
    et al.
    China Three Gorges Univ, Key Lab Geol Hazards Three Gorges Reservoir Area, Minist Educ, Yichang, Hubei, Peoples R China.;Natl Field Observat & Res Stn Landslides Three Go, Yichang, Peoples R China..
    Zou, Liangchao
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Wang, Qing
    China Three Gorges Univ, Inst Informat Sci & Technol, Yichang, Hubei, Peoples R China..
    Zhang, Guodong
    China Three Gorges Univ, Key Lab Geol Hazards Three Gorges Reservoir Area, Minist Educ, Yichang, Hubei, Peoples R China.;Natl Field Observat & Res Stn Landslides Three Go, Yichang, Peoples R China..
    Pile-Spacing Calculation of Anti-Slide Pile Based on Soil Arching Effect2020In: Advances in Civil Engineering / Hindawi, ISSN 1687-8086, E-ISSN 1687-8094, Vol. 2020, article id 7149379Article in journal (Refereed)
    Abstract [en]

    Anti-slide pile is one of the most frequently used measures in landslide control globally. Pile-spacing has always been determined by the load capacity of single piles or according to engineering empirical experience. Many engineering practices and laboratory experiments show that the soil arching effect exists in landslide control with anti-slide piles. In this study, we aim to calculate pile-spacing in terms of the soil arching effect. We investigated the pile-soil interaction mechanism and propose that, at the limit, the pile-back soil arch resists landslide thrust only. According to Mohr-Coulomb strength theory and limit equilibrium theories, we derived a new pile-spacing calculation equation. We verified the derived pile-spacing calculation equation with real projects. The calculated results are similar to those of practical engineering designs, in which the difference is within 10%. The equation can be used in anti-slide pile preliminary design. This study can be a reference for pile-spacing calculation based on the soil arching effect.

  • 18.
    Chen, Wenchuang
    et al.
    School of Civil Engineering, Sun Yat-Sen University, Zhuhai, 519082, China.
    Zhang, Yongliang
    State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing, 100084, China.
    Yang, James
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Yu, Huifeng
    State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing, 100084, China.
    Liang, Sendong
    State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing, 100084, China.
    Experiments and CFD modeling of a dual-raft wave energy dissipator2021In: Ocean Engineering, ISSN 0029-8018, E-ISSN 1873-5258, Vol. 237, article id 109648Article in journal (Refereed)
    Abstract [en]

    A wave energy dissipator (WED) is proposed in this paper, composed of two asymmetric hinged floaters and two hydraulic cylinders, with the purpose to resist wave-induced relative rotation around the hinge. Experimental studies are performed to explore its performance under a wide range of regular waves. Based on Reynolds-averaged Navier-Stokes equations, a 3D numerical model is set up, considering the non-linear interaction of wave and WED. The agreement between the experimental and numerical results is good. With the validated numerical model, the influence of the WED geometrical factors on energy conversion and wave transmission is examined. For a given raft length, the difference in energy conversion between the two multiplicative inverse fore-and-aft raft lengths is significant, which is dependent on the wave frequency. However, as for the wave transmission, the difference in between is insignificantly small, almost independent of the wave frequency. The findings demonstrate that, for energy conversion, its maximum value per unit length corresponds to a large fore-and-aft length ratio but a small total raft length. The combination of experiments and simulations provides reference for both understanding of hydrodynamic behaviours and design including parameter selection of the dissipator.

  • 19.
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Statistical Formulation of Generalized Tracer Retention in Fractured Rock2017In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 53, no 11, p. 8736-8759Article in journal (Refereed)
    Abstract [en]

    We study tracer retention in fractured rock by combing Lagrangian and time domain random walk frameworks, as well as a statistical representation of the retention process. Mass transfer is quantified by the retention time distribution that follows from a Lagrangian coupling between advective transport and mass exchange processes, applicable for advection-dominated transport. A unifying parametrization is presented for generalized diffusion using two rates denoted by k(1) and k(2) where k(1) is a forward rate and k(2) a reverse rate, plus an exponent as an additional parameter. For the Fickian diffusion model, k(1) and k(2) are related to measurable retention properties of the fracture-matrix by the method of moments, whereas for the non-Fickian case dimensional analysis is used. The derived retention time distributions are exemplified for interpreting tracer tests as well as for predictive modeling of expected tracer breakthrough. We show that non-Fickian effects can be notable when transport is upscaled based on a non-Fickian interpretation of a tracer test for which deviations from Fickianity are relatively small. The statistical representation of retention clearly shows the significance of the forward rate k(1) which depends on the active specific surface area and is the most difficult parameter to characterize in the field.

  • 20.
    Cvetkovic, Vladimir
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Painter, S.
    Outters, N.
    Selroos, Jan-Olof
    Swed. Nucl. Fuel and Waste Mgmt. Co., SE-10240 Stockholm, P.O. Box 5864, Sweden.
    Stochastic simulation of radionuclide migration in discretely fractured rock near the Aspo Hard Rock Laboratory2004In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 40, no 2, p. W02404-Article in journal (Refereed)
    Abstract [en]

    We study the migration of sorbing tracers through crystalline rock by combining relatively simple transport measures with particle tracking in a discrete fracture network. The rock volume is on a 100 m scale and is a replica of a thoroughly characterized site at the Aspo Hard Rock Laboratory, Sweden. Flow is driven by generic boundary conditions consistent with the natural gradient in the region. The emphasis is on the global effect of fracture-to-fracture hydraulic variability where individual fractures are assumed to be of uniform aperture. The transport measures are conditioned on two random variables: the water residence time (tau) and a parameter which quantifies the hydrodynamic control of retention (beta). Results are illustrated for two radionuclides: technetium (strongly sorbing) and strontium (weakly sorbing). It is found that the assumption of streamline routing or full mixing at fracture intersections has comparatively little impact on transport. The choice of the cubic or quadratic hydraulic law (i.e., relation between transmissivity and aperture) strongly affects water residence times but has little impact on average transport since it does not affect the statistics of beta. If the statistics of beta are known, then the distribution of water residence time (tau) is of little importance for transport. We assess the applicability of a linearized model beta = tau/b(ret) using two different approaches to estimate the effective retention'' aperture 2b(ret): from transmissivity data and from fracture density and flow porosity data. Under some conditions, these conventional estimates may provide acceptable representation of transport. The results stress the need for further studies on upscaling of tau, beta distributions as well as on estimating effective parameters for hydraulic control of retention.

  • 21.
    Cvetkovic, Vladimir
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Poteri, Antti
    Posiva Oy, Helsinki, Finland..
    Selroos, Jan-Olof
    Swedish Nuclear Fuel and Waste Management Co. (SKB), Stockholm, Sweden.
    Zou, Liangchao
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Inference of Retention Time From Tracer Tests in Crystalline Rock2020In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 56, no 2, article id e2019WR025266Article in journal (Refereed)
    Abstract [en]

    A statistical parametrization of transport combined with a new, general partition function for diffusive mass transfer (Cvetkovic, 2017, ) is here developed into a practical tool for evaluating tracer tests in crystalline rock. The research question of this study is how to separate the characteristic times of retention and advection, using tracer test information alone; this decoupling is critical for upscaling of transport. Three regimes are identified based on the unconditional mean number of trapping events. Analytical expressions are derived for inferring transport-retention parameters; these are first tested on a series of generic examples and then using two sets of tracer test data. Our results indicate that the key transport-retention parameters can be inferred separately with reasonable accuracy by a few simple steps, provided that the macrodispersion is not too large and retention not too strong. Of particular interest is inference of the retention time from the breakthrough curve peak that avoids costly asymptotic monitoring. Finally, we summarize the retention times as inferred from a series of nonsorbing tracer tests in the Swedish granite, demonstrating the uncertainties when estimating retention based on material and structural properties from samples. Possible strategies for reducing these uncertainties that combine improved understanding of crystalline rock evolution with numerical simulations are noted as topics for future research.

  • 22.
    Di Dato, Mariaines
    et al.
    Department of Computational Hydrosystems, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany.
    Bellin, Alberto
    Department of Civil, Environmental and Mechanical Engineering, University of Trento, Trento, Italy.
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Dagan, Gedeon
    School of Mechanical Engineering, Tel Aviv University, Tel Aviv, Israel.
    Dietrich, Peter
    Department of Monitoring and Exploration Technologies, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany; Center of Applied Geoscience, University of Tubingen, Tubingen, Germany.
    Fiori, Aldo
    DICITA, Roma Tre University, Rome, Italy.
    Teutsch, Georg
    Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany.
    Zech, Alraune
    Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Utrecht, The Netherlands.
    Attinger, Sabine
    Department of Computational Hydrosystems, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany; Institute of Environmental Science and Geography, University Potsdam, Potsdam-Golm, Germany.
    Baseflow Statistics in Aggregated Catchments2023In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 59, no 12, article id e2023WR035894Article in journal (Refereed)
    Abstract [en]

    This paper employs stochastic analysis to investigate the combined effect of temporal and spatial variability on the temporal variance of baseflow in large catchments. The study makes use of the well-known aggregated reservoir model, representing the catchment as a network of parallel linear reservoirs. Each reservoir models a sub-catchment as an independent unit whose discharge temporal variation is characterized by a response time. By treating the rainfall-generated recharge and the sub-catchment response times as random variables, the statistical temporal moments of total baseflow are quantified. Comparisons are made between the temporal variance of baseflow in the aggregated reservoir model and that of a single homogeneous reservoir to define an upscaled response time. The analysis of the statistical moments of the random baseflow reveals that the number of reservoirs N has a weak impact on baseflow variance, with ergodic conditions achieved even with a small number of reservoirs. The study highlights that the ratio between the recharge correlation time and the geometric mean of the sub-catchment response times plays a critical role in baseflow damping and the upscaled response. The results indicate that the dynamics of baseflow generation depend not only on the catchment hydro-geological structure but also on the variability of the input signal. This research underscores the importance of understanding the combined influences of hydro-geological factors and recharge input variability for baseflow prediction under uncertainty. The present study should be regarded as a first step, setting the theoretical framework for future research toward incorporating field data.

  • 23.
    Dóczi, Gabriella
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Rohracher, Harald
    Linköping Univ, Dept Themat Studies Technol & Social Change, SE-58183 Linköping, Sweden..
    Kordas, Olga
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Knowledge management in transition management: The ripples of learning2022In: Sustainable cities and society, ISSN 2210-6707, Vol. 78, article id 103621Article in journal (Refereed)
    Abstract [en]

    Despite the extensive literature on learning in urban transitions, we still have a limited understanding on how higher-order learning takes place in transition management and is spread within the transition arena. In this paper we analyze the efforts of transferring such embedded knowledge and its interrelation with learning through the examples of three Swedish municipalities engaged in urban transition management. To do so, we developed a framework of learning ripples that conceptualizes learning across social boundaries as an active and two-way process that goes beyond transferring and receiving knowledge, but also requires higher order learning that includes knowledge integration in the form of defining and formulating one's role and contributions to transitions. We found that higher order learning is largely influenced by the quality and frequency of interactions between the transferer and receivers. The further a stakeholder was located from the center of the transition arena in terms of direct interactions, the less chance occurred for higher order learning that resulted in tensions and conflicts in the collaboration. Our results show the problem as a lack of knowledge integration or a lack of conditions which allow stakeholders to articulate their views or develop an idea about their own role in the whole process.

  • 24.
    Earon, Robert
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Water and Environmental Engineering.
    Riml, Joakim
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Wu, Liwen
    Olofsson, Bo
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Water and Environmental Engineering.
    Insight into the influence of local streambed heterogeneity on hyporheic-zone flow characteristics2020In: Hydrogeology Journal, ISSN 1431-2174, E-ISSN 1435-0157, Vol. 28, no 8, p. 2697-2712Article in journal (Refereed)
    Abstract [en]

    Interaction between surface water and groundwater plays a fundamental role in influencing aquatic chemistry, where hyporheic exchange processes, distribution of flow paths and residence times within the hyporheic zone will influence the transport of mass and energy in the surface-water/groundwater system. Geomorphological conditions greatly influence hyporheic exchange, and heterogeneities such as rocks and clay lenses will be a key factor for delineating the hyporheic zone. Electrical resistivity tomography (ERT) and ground-penetrating radar (GPR) were used to investigate the streambed along a 6.3-m-long reach in order to characterise geological layering and distinct features which may influence parameters such as hydraulic conductivity. Time-lapse ERT measurements taken during a tracer injection demonstrated that geological features at the meter-scale played a determining role for the hyporheic flow field. The penetration depth of the tracer into the streambed sediment displayed a variable spatial pattern in areas where the presence of highly resistive anomalies was detected. In areas with more homogeneous sediments, the penetration depth was much more uniformly distributed than observed in more heterogeneous sections, demonstrating that ERT can play a vital role in identifying critical hydraulic features that may influence hyporheic exchange processes. Reciprocal ERT measurements linked variability and thus uncertainty in the modelled resistivity to the spatial locations, which also demonstrated larger variability in the tracer penetration depth, likely due to local heterogeneity in the hydraulic conductivity field.

  • 25. Eriksson, Helen
    et al.
    Johansson, Tim
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Olsson, Per-Ola
    Andersson, Maria
    Engvall, Jakob
    Hast, Isak
    Harrie, Lars
    Requirements, Development, and Evaluation of A National Building Standard-A Swedish Case Study2020In: ISPRS International Journal of Geo-Information, ISSN 2220-9964, Vol. 9, no 2, article id 78Article in journal (Refereed)
    Abstract [en]

    The aim of this paper is to present a proposal for a national building standard in Sweden. We define requirements for the proposed standard, e.g., it should support development of 3D city models, connect to building information models (BIM) and national registers and be based on a national classification system for the urban environment. Based on these requirements we develop an Application Domain Extension (ADE) of the building model in the proposed CityGML 3.0 standard denoted CityGML Sve-Test. CityGML 3.0 includes several new features of interest, e.g., the space concept, enhanced possibilities to convert data, and to link to other standards. In our study we create test data according to CityGML Sve-Test and evaluate it against the requirements. It is shown that BIM models (in Industry Foundation Classes, IFC, format) can be converted to CityGML Sve-Test and that a classification system facilitates this conversion. The CityGML Sve-Test dataset can be used to increase the automation level in building permissions checking and a related study shows that CityGML 3.0 has capabilities to link to legal information and be a base for 3D cadastral index maps. Based on our experience, we suggest that the national building standard should conform to international standards and, if possible, include a classification system. The exchange format (GML, JSON etc.) might change, but to be based on a standardized data model ensures harmonized structures and concepts.

  • 26.
    Eriksson, Petra
    et al.
    Uppsala Univ, Dept Art Hist & Conservat, S-75236 Uppsala, Sweden..
    Johansson, Tim
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Towards Differentiated Energy Renovation Strategies for Heritage-Designated Multifamily Building Stocks2021In: Heritage, E-ISSN 2571-9408, Vol. 4, no 4, p. 4318-4334Article in journal (Refereed)
    Abstract [en]

    The historic building stock is not homogeneous, which implies a need for differentiated energy renovation strategies in order to balance energy efficiency requirements and building conservation goals. This paper presents a new method for developing a base for differentiated energy renovation strategies for heritage-classified multifamily building stocks. Our suggested method combines different building databases using an extract, transform and load (ETL) technology. The method for this study was tested on the available information for heritage-designated and -classified multifamily buildings in the municipality of Stockholm, Sweden, and in the county of Halland, Sweden. The two cases reflect the heterogeneity of the Swedish Building stock. An important achievement is that the results visualise the relationship, not detectable before, between energy use, energy performance, year of construction and heritage classification within each of the selected building stocks. A specific result is that the energy-saving potential in the older building stock is insignificant in relation to the entire stock. The results contribute to an improved understanding of relationships both within and between the two historic building stocks, which is useful for developing differentiated energy renovation strategies.

  • 27.
    Ermolaev, Evgheni
    et al.
    Swedish Univ Agr Sci SLU, Dept Energy & Technol, Box 7032, SE-75007 Uppsala, Sweden..
    Sundberg, Cecilia
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure. Swedish Univ Agr Sci SLU, Dept Energy & Technol, Box 7032, SE-75007 Uppsala, Sweden..
    Pell, Mikael
    Swedish Univ Agr Sci SLU, Dept Mol Sci, Box 7015, SE-75007 Uppsala, Sweden..
    Smars, Sven
    Swedish Univ Agr Sci SLU, Dept Energy & Technol, Box 7032, SE-75007 Uppsala, Sweden..
    Jonsson, Håkan
    Swedish Univ Agr Sci SLU, Dept Energy & Technol, Box 7032, SE-75007 Uppsala, Sweden..
    Effects of moisture on emissions of methane, nitrous oxide and carbon dioxide from food and garden waste composting2019In: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 240, article id UNSP 118165Article in journal (Refereed)
    Abstract [en]

    Globally, waste generation is continually increasing, with landfill as the main destination for biological waste. Composting is a simple alternative for handling waste, but when poorly managed poses a risk of greenhouse gas emissions. The moisture content of substrate affects emissions of methane (CH4) and nitrous oxide (N2O) from composting, but the scale and mechanisms behind these effects are poorly understood. This study examined effects of different moisture levels (44-66%) on CH4, N2O and carbon dioxide (CO2) emissions during 20 days of composting food and garden waste under controlled conditions (55 degrees C, 16% oxygen) in a 200-L reactor. Total CO2 emissions were 400-500 g CO2-C kg(-1) initial C. Total CH4 emissions were highest, 35 g CH4-C kg(-1) initial C, for the wettest substrate (66% moisture) and decreased exponentially with declining moisture content, with the lowest total emissions, 0.04 g CH4-C kg(-1) initial C, observed with the driest substrate. Total N2O emissions were negatively correlated with moisture content, decreasing from 1.2 g N2O-N kg(-1) initial N at 44% moisture to 0.3 g N2O-N kg(-1) initial N at 59%, but the wettest substrate (66% moisture) had the highest N2O emissions, 1.4 g N2O-N kg(-1) initial N. NH4-N accumulated in the wettest material, suggesting that the increased N2O emissions were due to reduced oxygen availability. The results indicate potential to reduce greenhouse gas emissions from large-scale composting by adjusting the moisture content at different stages of composting, thus lowering its overall environmental impact. This finding can be used in guidelines for large-scale composting process to avoid moisture conditions causing large greenhouse gas emissions. Elsevier Ltd. All rights reserved.

  • 28.
    Faure, Xavier
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Johansson, Tim
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Pasichnyi, Oleksii
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    The Impact of Detail, Shadowing and Thermal Zoning Levels on Urban Building Energy Modelling (UBEM) on a District Scale2022In: Energies, E-ISSN 1996-1073, Vol. 15, no 4, p. 1525-, article id 1525Article in journal (Refereed)
    Abstract [en]

    New modelling tools are required to accelerate the decarbonisation of the building sector. Urban building energy modelling (UBEM) has recently emerged as an attractive paradigm for analysing building energy performance at district and urban scales. The balance between the fidelity and accuracy of created UBEMs is known to be the cornerstone of the model's applicability. This study aimed to analyse the impact of traditionally implicit modeller choices that can greatly affect the overall UBEM performance, namely, (1) the level of detail (LoD) of the buildings' geometry; (2) thermal zoning; and (3) the surrounding shadowing environment. The analysis was conducted for two urban areas in Stockholm (Sweden) using MUBES-the newly developed UBEM. It is a bottom-up physics-based open-source tool based on Python and EnergyPlus, allowing for calibration and co-simulation. At the building scale, significant impact was detected for all three factors. At the district scale, smaller effects (<2%) were observed for the level of detail and thermal zoning. However, up to 10% difference may be due to the surrounding shadowing environment, so it is recommended that this is considered when using UBEMs even for district scale analyses. Hence, assumptions embedded in UBEMs and the scale of analysis make a difference.

  • 29.
    Faure, Xavier
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Lebrun, Régis
    Applied Mathematics Team, Airbus Research & Technology, 22 rue du Gouverneur Général Eboué, 92130 Issy les Moulineaux, France, 22 rue du Gouverneur Général Eboué.
    Pasichnyi, Oleksii
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Impact of time resolution on estimation of energy savings using a copula-based calibration in UBEM2024In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 311, article id 114134Article in journal (Refereed)
    Abstract [en]

    Urban Building Energy modelling (UBEM) has emerged in the last decade as an important tool to accelerate energy transition in the building sector. To fulfil one of its major purposes - forecasting energy savings for potential energy conservation measures at an urban scale, several challenges are still to be addressed. Two key challenges include: 1) the need to calibrate models with a large number of unknown parameters across numerous buildings (either individually or through archetype representation); 2) the limited availability of high-resolution measured data, which raises concerns about calibrated models based solely on yearly values for accurate energy savings forecast. This study addresses these challenges using a case study of 35 buildings in a district in Stockholm, Sweden. Firstly, a new iterative Approximate Bayesian Computation (ABC) method for calibration is proposed, incorporating a copula-based sampling process at each iteration. Secondly, the new calibration process is applied with three different time resolutions to examine the impact of data resolution on forecasted energy usage, particularly when applied to a classical energy conservation measure. Results demonstrate the efficiency of the new method across the 35 buildings, facilitating the rapid population of a final joint distribution for the nine unknown parameters considered in each building. While the marginals may be strongly influenced by the time resolution, the forecasted energy consumption remains identical across the three analysed time resolutions. However, a noticeable difference is observed when the ECM pertains to a formerly unknown or known parameter.

  • 30.
    Ferdous, Md Ruknul
    et al.
    IHE Delft Inst Water Educ, Dept Integrated Water Syst & Governance, NL-2611 AX Delft, Netherlands.;Univ Amsterdam, Fac Social & Behav Sci, NL-1012 WX Amsterdam, Netherlands..
    Wesselink, Anna
    IHE Delft Inst Water Educ, Dept Integrated Water Syst & Governance, NL-2611 AX Delft, Netherlands..
    Brandimarte, Luigia
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Slager, Kymo
    Deltares, NL-2600 MH Delft, Netherlands..
    Zwarteveen, Margreet
    IHE Delft Inst Water Educ, Dept Integrated Water Syst & Governance, NL-2611 AX Delft, Netherlands.;Univ Amsterdam, Fac Social & Behav Sci, NL-1012 WX Amsterdam, Netherlands..
    Di Baldassarre, Giuliano
    IHE Delft Inst Water Educ, Dept Integrated Water Syst & Governance, NL-2611 AX Delft, Netherlands.;Uppsala Univ, Dept Earth Sci, S-75236 Uppsala, Sweden.;CNDS, Ctr Nat Hazards & Disaster Sci, S-75236 Uppsala, Sweden..
    Socio-hydrological spaces in the Jamuna River floodplain in Bangladesh2018In: Hydrology and Earth System Sciences, ISSN 1027-5606, E-ISSN 1607-7938, Vol. 22, no 10, p. 5159-5173Article in journal (Refereed)
    Abstract [en]

    Socio-hydrology aims to understand the dynamics and co-evolution of coupled human-water systems, with research consisting of generic models as well as specific case studies. In this paper, we propose a concept to help bridge the gap between these two types of socio-hydrological studies: socio-hydrological spaces (SHSs). A socio-hydrological space is a geographical area in a landscape. Its particular combination of hydrological and social features gives rise to the emergence of distinct interactions and dynamics (patterns) between society and water. Socio-hydrological research on human-flood interactions has found two generic responses, "fight" or "adapt". Distilling the patterns resulting from these responses in case studies provides a promising way to relate contextual specificities to the generic patterns described by conceptual models. Through the use of SHSs, different cases can be compared globally without aspiring to capturing them in a formal model. We illustrate the use of SHS for the Jamuna floodplain, Bangladesh. We use narratives and experiences of local experts and inhabitants to empirically describe and delimit SHS. We corroborated the resulting classification through the statistical analysis of primary data collected for the purpose (household surveys and focus group discussions) and secondary data (statistics, maps etc.). Our example of the use of SHSs shows that the concept draws attention to how historical patterns in the co-evolution of social behaviour, natural processes and technological interventions give rise to different landscapes, different styles of living and different ways of organising livelihoods. This provides a texture to the more generic patterns generated by socio-hydrological models, promising to make the resulting analysis more directly useful for decision makers. We propose that the usefulness of this concept in other floodplains, and for other socio-hydrological systems than floodplains, should be explored.

  • 31.
    Fiori, Aldo
    et al.
    Roma Tre Univ, Dept Engn, Rome, Italy..
    Zarlenga, Antonio
    Roma Tre Univ, Dept Engn, Rome, Italy..
    Bellin, Alberto
    Univ Trento, Dept Civil Environm & Mech Engn, Trento, Italy..
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Dagan, Gedeon
    Tel Aviv Univ, Sch Mech Engn, Ramat Aviv, Israel..
    Groundwater Contaminant Transport: Prediction Under Uncertainty, With Application to the MADE Transport Experiment2019In: Frontiers in Environmental Science, E-ISSN 2296-665X, Vol. 7, article id 79Article in journal (Refereed)
    Abstract [en]

    Transport of solutes in porous media at the laboratory scale is governed by an Advection Dispersion Equation (ADE). The advection is by the fluid velocity U and dispersion by D-dL = U alpha(dL), where the longitudinal dispersivity alpha(dL) is of the order of the pore size. Numerous data revealed that the longitudinal spreading of plumes at field scale is characterized by macrodispersivity alpha(L), larger than alpha(dL) by orders of magnitude. This effect is attributed to heterogeneity of aquifers manifesting in the spatial variability of the logconductivity Y. Modeling Y as a stationary random field and for mean uniform flow (natural gradient), alpha(L) could be determined in an analytical form by a first order approximation in sigma(2)(Y) (variance of Y) of the flow and transport equations. Recently, models and numerical simulations for solving transport in highly heterogeneous aquifers (sigma(2)(Y) > 1), primarily in terms of the mass arrival (the breakthrough curve BTC), were advanced. In all cases ergodicity, which allows to exchange the unknown BTC with the ensemble mean, was assumed to prevail for large plumes, compared to the logconductivity integral scale. Besides, the various statistical parameters characterizing the logconductivity structure as well as the mean flow were assumed to be known deterministically. The present paper investigates the uncertainty of the non-ergodic BTC due to the finiteness of the plume size as well as due to the uncertainty of the various parameters on which the BTC depends. By the use of a simplified transportmodel we developed in the past (which led to accurate results for ergodic plumes), we were able to get simple results for the variance of the BTC. It depends in an analytical manner on the flow parameters as well as on the dimension of the initial plume relative to the integral scale of logconductivity covariance. The results were applied to the analysis of the uncertainty of the plume spatial distribution of the MADE transport experiment. This was achieved by using the latest, recent, analysis of the MADE aquifer conductivity data.

  • 32.
    Fontan, Angela
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Decision and Control Systems (Automatic Control).
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Johansson, Karl H.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Decision and Control Systems (Automatic Control).
    On behavioral changes towards sustainability for connected individuals: a dynamic decision-making approach2022In: IFAC: PapersOnLine, Elsevier BV , 2022, Vol. 55, no 41, p. 20-25Conference paper (Refereed)
    Abstract [en]

    In the context of sustainable lifestyle it has been observed that, while expressing eco-positive attitudes, individuals often do not act accordingly in their habitual behavior. This gap, termed the "value-action" gap, has been explained in terms of desire to seek social approval or as a consequence of the presence of overriding conflicting goals, associated for instance with material costs. In this work, we study a two-scale networked model for dynamic decision-making in which interacting agents are able to exchange opinions and discuss the different reasons they produce their choices and, in addition, are able to observe the actions of their neighbors in the network and adjust their preferences. Coupling on the two scales leads to a reduced value-action gap, and ultimately to a consensus. A numerical example illustrates the effect that tradeoffs between goals and social pressure have on the behavior of the group.

  • 33.
    Fontan, Angela
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Decision and Control Systems (Automatic Control).
    Farjadnia, Mahsa
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Decision and Control Systems (Automatic Control).
    Llewellyn, Joseph
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Strategic Sustainability Studies.
    Katzeff, Cecilia
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Strategic Sustainability Studies.
    Molinari, Marco
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Johansson, Karl H.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Decision and Control Systems (Automatic Control).
    Social interactions for a sustainable lifestyle: The design of an experimental case study2023Conference paper (Refereed)
    Abstract [en]

    Every day we face numerous lifestyle decisions, some dictated by habits and somemore conscious, which may or may not promote sustainable living. Aided by digital technology,sustainable behaviors can diffuse within social groups and inclusive communities. This paperoutlines a longitudinal experimental study of social influence in behavioral changes towardsustainability, in the context of smart residential homes. Participants are students residing inthe housing on campus referred to as KTH Live-In Lab, whose behaviors will be observedw.r.t. key lifestyle choices, such as food, resources, mobility, consumption, and environmentalcitizenship. The focus is on the preparatory phase of the case study and the challengesand limitations encountered during its setup. In particular, this work proposes a definitionof sustainability indicators for environmentally significant behaviors, and hypothesizes that,through digitalization of a household into a social network of interacting tenants, sustainableliving can be promoted.

  • 34.
    Gitau, James K.
    et al.
    Univ Nairobi, Wangari Maathai Inst Peace & Environm Studies, POB 2905-0065, Nairobi, Kenya.;World Agroforestry Ctr ICRAF, POB 30677-00100, Nairobi, Kenya..
    Sundberg, Cecilia
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Mendum, Ruth
    Penn State Univ, Off Int Programs, Coll Agr Sci, 106 Agr Adm Bldg, University Pk, PA 16802 USA..
    Mutune, Jane
    Univ Nairobi, Wangari Maathai Inst Peace & Environm Studies, POB 2905-0065, Nairobi, Kenya..
    Njenga, Mary
    Univ Nairobi, Wangari Maathai Inst Peace & Environm Studies, POB 2905-0065, Nairobi, Kenya.;World Agroforestry Ctr ICRAF, POB 30677-00100, Nairobi, Kenya..
    Use of Biochar-Producing Gasifier Cookstove Improves Energy Use Efficiency and Indoor Air Quality in Rural Households2019In: Energies, E-ISSN 1996-1073, Vol. 12, no 22, article id 4285Article in journal (Refereed)
    Abstract [en]

    Biomass fuels dominate the household energy mix in sub-Saharan Africa. Much of it is used inefficiently in poorly ventilated kitchens resulting in indoor air pollution and consumption of large amounts of wood fuel. Micro-gasification cookstoves can improve fuel use efficiency and reduce indoor air pollution while producing char as a by-product. This study monitored real-time concentrations of carbon monoxide (CO), carbon dioxide (CO2) and fine particulate matter (PM2.5), and amount of firewood used when households were cooking dinner. Twenty-five households used the gasifier cookstove to cook and five repeated the same test with three-stone open fire on a different date. With the gasifier, the average corresponding dinner time CO, CO2, and PM2.5 concentrations were reduced by 57%, 41%, and 79% respectively compared to three-stone open fire. The gasifier had average biomass-to-char conversion efficiency of 16.6%. If the produced char is used as fuel, households could save 32% of fuel compared to use of three-stone open fire and 18% when char is used as biochar, for instance. Adoption of the gasifier can help to reduce the need for firewood collection, hence reducing impacts on the environment while saving on the amount of time and money spent on cooking fuel.

  • 35.
    Gitau, K. J.
    et al.
    Univ Nairobi, Wangari Maathai Inst Peace & Environm Studies, POB 2905-0065, Nairobi, Kenya.;World Agroforestry Ctr ICRAF, POB 30677-00100, Nairobi, Kenya..
    Mutune, J.
    Univ Nairobi, Wangari Maathai Inst Peace & Environm Studies, POB 2905-0065, Nairobi, Kenya..
    Sundberg, Cecilia
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure. Swedish Univ Agr Sci SLU, Dept Energy & Technol, Uppsala, Sweden..
    Mendum, R.
    Penn State Univ, Off Int Programs, Coll Agr Sci, University Pk, PA 16802 USA..
    Njenga, M.
    Univ Nairobi, Wangari Maathai Inst Peace & Environm Studies, POB 2905-0065, Nairobi, Kenya.;World Agroforestry Ctr ICRAF, POB 30677-00100, Nairobi, Kenya..
    Factors influencing the adoption of biochar-producing gasifier cookstoves by households in rural Kenya2019In: Energy for Sustainable Development, ISSN 0973-0826, E-ISSN 2352-4669, Vol. 52, p. 63-71Article in journal (Refereed)
    Abstract [en]

    Fuel wood is the main source of cooking and heating energy in developing countries. However, it is combusted in inefficient cookstoves, leading to more fuel use and human health problems resulting from exposure to smoke. Thus new, efficient cooking systems that can address some of these problems are required. This study examined gasifier cookstove use in Kwale County, Kenya, and factors influencing adoption. Gasifier stoves were issued for free to 50 households, which were surveyed after 2-3 months of use. The results showed that the stove was used by 96% of the households at varying frequencies, 40% of them used it almost every day with 4% switching to only using the new stove. All the users appreciated it because it saved fuel, produced less smoke, and produced charcoal to use for either cooking or soil amendment. Compared with the traditional three-stone open fire, the gasifier stove was reported to be easier to clean (98% of respondents), easier to adjust the heat (88%), easier to handle (58%), caused less exposure to heat (96%) and was cleaner for pots and the kitchen (98%). Another reported benefit of the gasifier stove was that it needed no tending (i.e., adjusting wood and blowing to keep the flames burning). The gasifier stove was mainly used to cook foods that required a short cooking time and many preferred to use it to cook dinner. However, the households encountered some challenges with using the gasifier stoves. For example, fuel preparation, reloading, and lighting were reported as challenges by 42%, 77% and 19%, respectively, of the 83% of households who reported challenges. These challenges could be overcome by improving stove design and by devising innovative ways of cutting fuel into small pieces. 2019 The Authors. Published by Elsevier Inc. on behalf of International Energy Initiative.

  • 36.
    Guo, Wencheng
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Hydraulic Engineering. Huazhong Univ Sci & Technol, Sch Hydropower & Informat Engn, Wuhan 430074, Peoples R China..
    Yang, James
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Hydraulic Engineering. KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure. Vattenfall AB, R&D Labs, SE-81426 Alvkarleby, Sweden..
    Yang, J. B.
    Wuhan Univ, State Key Lab Water Resources & Hydropower Engn S, Wuhan 430072, Peoples R China..
    Effect of throttling orifice head loss on dynamic behavior of hydro-turbine governing system with air cushion surge chamber2019In: 29th iahr symposium on hydraulic machinery and systems, IOP PUBLISHING LTD , 2019, article id 052018Conference paper (Refereed)
    Abstract [en]

    This paper aims to study the effect of throttling orifice head loss on the dynamic behavior of the hydro-turbine governing system with air cushion surge chamber. Firstly, a nonlinear mathematical model of hydro-turbine governing system considering the nonlinear head loss of throttling orifice is established. Then, the nonlinear dynamic behavior of the hydro-turbine governing system is investigated by using the Hopf bifurcation theory and direct numerical integration. The stability and dynamic response of the system are detailed described. Finally, the effect mechanism of throttling orifice head loss on the dynamic behavior of system is revealed based on the comparison between the cases with nonlinear head loss and no head loss. The results indicate that the mathematical model considering the nonlinear head loss of throttling orifice for the hydro-turbine governing system is a fifth-order nonlinear state equation. The system goes through Hopf bifurcation at the bifurcation points and the type of Hopf bifurcation is supercritical. The domain at the bottom of the bifurcation line is the stable domain The throttling orifice cannot affect the system stability through its head loss. The throttling orifice can affect the system dynamic response through its head loss. The throttling orifice head loss is favorable for the damping of the water level oscillation in the surge chamber.

  • 37.
    Gustafsson, Kåre
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Sustainability and Environmental Engineering. Stockholm Exergi, Stockholm, Sweden..
    Sadegh-Vaziri, Ramiar
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Grönkvist, Stefan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Energy Processes.
    Levihn, Fabian
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.). Stockholm Exergi, Stockholm, Sweden.
    Sundberg, Cecilia
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure. Swedish Univ Agr Sci SLU, Dept Energy & Technol, Uppsala, Sweden.
    BECCS with combined heat and power: Assessing the energy penalty2021In: International Journal of Greenhouse Gas Control, ISSN 1750-5836, E-ISSN 1878-0148, Vol. 108, article id 103248Article in journal (Refereed)
    Abstract [en]

    Bio-energy with carbon capture and storage (BECCS) is widely recognised as an important carbon dioxide removal technology. Nevertheless, BECCS has mostly failed to move beyond small-scale demonstration units. One main factor is the energy penalty incurred on power plants. In previous studies, this penalty has been determined to be 37.2 %?48.6 % for the amine capture technology. The aim of this study is to quantify the energy penalty for adding the hot potassium carbonate (HPC) capture technology to a biomass-fired combined heat and power (CHP) plant, connected to a district heating system. In this context, the energy driving the capture process is partly recovered as useful district heating. Therefore, a modified energy penalty is proposed, with the inclusion of recovered heat. This inclusion is especially meaningful if the heat has a substantial monetary value. The BECCS system is examined using thermodynamic analysis, coupled with modelling of the capture process in Aspen PlusTM. Model validation is performed with data from a BECCS test facility. The results of this study show that the modified energy penalty is in the range of 2%?4%. These findings could potentially increase the attractiveness of BECCS as a climate abatement option in a district heating CHP setting.

  • 38.
    Hamisi, Rajabu
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Water and Environmental Engineering.
    Renman, Agnieszka
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Water and Environmental Engineering.
    Renman, Gunno
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Water and Environmental Engineering.
    Wörman, Anders
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Thunvik, Roger
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Water and Environmental Engineering.
    Long-term phosphorus sorption and leaching in sand filters for onsite treatment systems2022In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 833, p. 155254-155254, article id 155254Article in journal (Refereed)
    Abstract [en]

    The sorption capacities of sand filters used for onsite wastewater treatment and their associated risks of phosphorus (P) leaching on contact with rainwater were investigated in column experiments and with modelling tool for over 300 days. Columns packed with sand were exposed to real domestic wastewater of different characteristics and hydraulic loading modes. The wastewater fed into the columns was effluent collected from three different treatment units in the field: a septic tank (ST), biofiltration tank (BF) and Polonite® filter bag (PO). The risk of P leaching to groundwater and surface water was also assessed, by exposing the same sand columns to natural rainwater. Overall results indicated that sand soils can exhibit different adsorption and desorption capacities for electrical conductivity (EC), Total-P, phosphate-P and total suspended solids, depending on the characteristics of influent wastewater, loading rate and total operation time. The removal efficiencies of the sand columns increased in the order ST (98.16 %) > PO (93.36%) > BF (81.57%) for PO4-P and slightly decreased ST (97.11 %) > PO (92.06%) > BF (76.76%) for Total-P columns. All sand columns loaded with actual wastewater solutions from septic tanks and biofiltration tank have demonstrated high risks of phosphorus leaching (> 99.99%) to the groundwater. The modelling was successful captured behavior of EC tracer and adsorption of PO4-P with acceptable prediction uncertainty in the PO < 8% columns. The modelling results indicated that the decrease of loading rate from 83.3 mL d-1 to 20.83 mL d-1 led to an average increase of removal efficiency and prolong operational lifetime and mass of adsorbed Total-P in the sand soil. This study concludes that sand is a valuable filter medium at low loading rate for phosphorus removal in full-scale operations of onsite treatment systems, however very vulnerable for leaching P when in contact with rainwater.

  • 39.
    Hamisi, Rajabu
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Water and Environmental Engineering.
    Renman, Gunno
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Water and Environmental Engineering.
    Renman, Agnieszka
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Water and Environmental Engineering.
    Wörman, Anders
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Phosphorus sorption and leaching in sand filters used for onsite wastewater treatment - a column experimentIn: Article, book review (Refereed)
    Abstract [en]

    The sorption capacities of filter sands used for onsite wastewater treatment and their associated risks of phosphorus (P) leakage on contact with rainwater were investigated in column experiments and modelling studies. Columns packed with sand were exposed to real domestic wastewater of different characteristics and hydraulic loading modes. The wastewater fed into the columns was effluent collected from three different treatment units in the field: a septic tank (ST), biofiltration tank (BF) and Polonite® filter bag (PO). The risk of P leaching to groundwater and surface water was also assessed, by exposing the same sand columns to artificial rainwater. The results indicated that sand columns can exhibit different adsorption capacities for Total-P, phosphate-P and total suspended solids, depending on the characteristics of influent wastewater. The adsorption capacity increased in the order ST > BF > PO, based on availability of organic matter to form biofilm. Effluent from Pol columns was significantly clearer, indicating lower organics content, than effluent from ST and BF columns. The modelled breakthrough curves for Total-P desorption agreed satisfactorily with the measured values, but further model improvement is needed.

  • 40.
    Hamisi, Rajabu
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Water and Environmental Engineering.
    Renman, Gunno
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Water and Environmental Engineering.
    Renman, Agnieszka
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Water and Environmental Engineering.
    Wörman, Anders
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Simulating the hydraulic dynamics and treatment performance of a sequencing batch flow constructed wetlandIn: Article, book review (Refereed)
    Abstract [en]

    In a six-month field trial, the performance of a full-scale sequencing batch flow constructed wetland (SBCW) treating on-site wastewater was determined. The filling and draining periods lasted 5-9 days, depending on wastewater production by users (two households). The results indicated that the SBCW system efficiently removed ammonium-nitrogen (NH4-N, 76%) and Escherichia coli (89%). However, draining by pumping increased preferential water flow and considerably limited removal of dissolved phosphorus (PO4-P) in the filter bed. Analysis of water samples from nine points and three vertical levels of the wetland bed showed that pumping aerated the bed, resulting in removal of NH4-N being highest in the top 0-0.2 m layer (43%) intermediate in the 0.2-0.4 m layer (32%), and lowest in the deep (0.4-0.6 m) layer (4%). Complementary modeling using COMSOL Multiphysics software to predict the hydraulic dynamics for three different SBCW designs indicated that the drainage system of the present SBCW should be re-designed to increase contact time and aeration, for improved phosphorus and nitrogen removal.

  • 41.
    Hao, Meimei
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering. School of Water Conservancy and Transportation, Zhengzhou University, Zhengzhou, 450001, China.
    Zhang, Jia
    School of Water Conservancy and Transportation, Zhengzhou University, Zhengzhou, 450001, China.
    Zou, Liangchao
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Water and Environmental Engineering.
    Li, Xiaolong
    School of Water Conservancy and Transportation, Zhengzhou University, Zhengzhou, 450001, China.
    Zhong, Yanhui
    School of Water Conservancy and Transportation, Zhengzhou University, Zhengzhou, 450001, China.
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Influence of component parameters on propagation characteristics of foaming polyurethane grout in rock fractures2024In: Construction and Building Materials, ISSN 0950-0618, E-ISSN 1879-0526, Vol. 428, article id 136227Article in journal (Refereed)
    Abstract [en]

    Polyurethane grouting is an important technical solution used for seepage prevention and mechanical reinforcement of fractured rock. Various components of polyurethane grout significantly affect the grout properties and propagation behavior. The present study focuses on the crucial role of component parameters in controlling the propagation process and designing grouting parameters for foaming polyurethane grout. A coupled modeling approach combining chemical reactions and flow field analysis is developed to investigate the polyurethane foaming process. The proposed modeling approach is validated by comparing simulation results with experimental data from the literature. The influence of key component parameters: isocyanate index, initial water concentration and physical blowing agent, on the propagation characteristics (including propagation distance, maximum pressure, final density, reaction time and maximum temperature) of foaming polyurethane grout in rock fractures are further analyzed. The results reveal two distinct types of effects caused by the components, i.e., a monotonic relationship and a parabolic trend. Critical values are identified for the impact of isocyanate index on maximum propagation distance, final density and characteristic time, as well as for the influence of physical blowing agent on maximum propagation distance, final density and maximum pressure. Other parameters demonstrated a monotonic relationship. Additionally, a quantitative assessment is conducted to evaluate the impact of multiple components on propagation characteristics. The finding indicates that the initial water concentration has a significant effect on all properties, while isocyanate index exerts a more pronounced impact on reaction time and maximum temperature. The effect of the physical blowing agent is relatively minor compared to other factors. This study is helpful for material selection and proportioning of polyurethane grout in practical engineering applications.

  • 42.
    Hao, Shuang
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Wörman, Anders
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Riml, Joakim
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Bottacin-Busolin, Andrea
    Univ Padua, Dept Ind Engn, Via Venezia 1, I-35121 Padua, Italy..
    A Model for Assessing the Importance of Runoff Forecasts in Periodic Climate on Hydropower Production2023In: Water, E-ISSN 2073-4441, Vol. 15, no 8, article id 1559Article in journal (Refereed)
    Abstract [en]

    Hydropower is the largest source of renewable energy in the world and currently dominates flexible electricity production capacity. However, climate variations remain major challenges for efficient production planning, especially the annual forecasting of periodically variable inflows and their effects on electricity generation. This study presents a model that assesses the impact of forecast quality on the efficiency of hydropower operations. The model uses ensemble forecasting and stepwise linear optimisation combined with receding horizon control to simulate runoff and the operation of a cascading hydropower system. In the first application, the model framework is applied to the Dalalven River basin in Sweden. The efficiency of hydropower operations is found to depend significantly on the linkage between the representative biannual hydrologic regime and the regime actually realised in a future scenario. The forecasting error decreases when considering periodic hydroclimate fluctuations, such as the dry-wet year variability evident in the runoff in the Dalalven River, which ultimately increases production efficiency by approximately 2% (at its largest), as is shown in scenarios 1 and 2. The corresponding potential hydropower production is found to vary by 80 GWh/year. The reduction in forecasting error when considering biennial periodicity corresponds to a production efficiency improvement of about 0.33% (or 13.2 GWh/year).

  • 43. Henryson, K.
    et al.
    Kätterer, T.
    Tidåker, P.
    Sundberg, Cecilia
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure. Swedish University of Agricultural Sciences (SLU), Department of Energy and Technology, P.O. Box 7032, Uppsala, 750 07, Sweden.
    Soil N2O emissions, N leaching and marine eutrophication in life cycle assessment – A comparison of modelling approaches2020In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 725, article id 138332Article in journal (Refereed)
    Abstract [en]

    Nitrogen fertilisation is an essential part of modern agriculture, providing food for a growing human population, but also causing environmental impacts when reactive nitrogen (N) is released to the environment. The amount and impact of these emissions are difficult to quantify in life cycle assessment (LCA), due to their site-dependent nature. This study compared seven models for direct soil nitrous oxide (N2O) emissions, seven models for N leaching and five characterisation models for marine eutrophication impact assessment, selected to represent medium-effort options for accounting for spatial variation in emissions and impact assessment. In a case study, the models were applied to wheat cultivation at two Swedish sites to estimate climate and marine eutrophication impact. Direct N2O emissions estimated by the models varied by up to five-fold at one of the sites and contributed 21–56% of the total climate impact. Site-dependent models gave both lower and higher N2O emissions estimates than the site-generic Tier 1 model from the Intergovernmental Panel on Climate Change (IPCC). Estimated N leaching also varied by up to fivefold at one of the sites and contributed 47–93% of the total eutrophication potential, depending on model choice. All site-dependent models estimated lower N leaching than the site-generic IPCC Tier 1 model. Marine eutrophication impact estimates varied by almost an order of magnitude depending on characterisation model choice. The large variation between models found in this study highlights the importance of model choice for N emissions and marine eutrophication impact assessment in LCA of crop cultivation. Due to the divergence of model outcomes and different limitations of some of the models, no general recommendations on choosing soil N2O emissions model, N leaching model or characterisation model for marine eutrophication could be given.

  • 44.
    Henryson, Kajsa
    et al.
    Swedish Univ Agr Sci SLU, Dept Energy & Technol, POB 7032, S-75007 Uppsala, Sweden..
    Hansson, Er-Anders
    Swedish Univ Agr Sci SLU, Dept Energy & Technol, POB 7032, S-75007 Uppsala, Sweden..
    Katterer, Thomas
    Swedish Univ Agr Sci SLU, Dept Ecol, POB 7044, S-75007 Uppsala, Sweden..
    Tidaker, Pernilla
    Swedish Univ Agr Sci SLU, Dept Energy & Technol, POB 7032, S-75007 Uppsala, Sweden..
    Sundberg, Cecilia
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Environmental performance of crop cultivation at different sites and nitrogen rates in Sweden2019In: Nutrient Cycling in Agroecosystems, ISSN 1385-1314, E-ISSN 1573-0867, Vol. 114, no 2, p. 139-155Article in journal (Refereed)
    Abstract [en]

    Nitrogen (N) fertilisation has positive and negative effects on the environmental impact of crop cultivation. The mechanisms governing these effects are highly site-dependent, a factor often ignored in assessments of the environmental impact of crop cultivation. By assessing outputs of crop rotations using a life cycle approach, this study explored how greenhouse gas emissions and marine eutrophication caused by crop cultivation (including upstream processes such as production of farm inputs) depend on fertiliser rate and the site at which the cultivation occurs. Cereal unit (CU) was used as the functional unit. The calculations were based on data from multi-site long-term field experiments in Sweden and site-dependent data and models for non-measured processes. Cultivation at three N levels was evaluated, where the highest N rate was close to current average practices and the lowest level corresponded to one-third of that. Site characteristics had a stronger influence on both greenhouse gas emissions and marine eutrophication (variations of up to 330% and 490%, respectively, within N levels) than N level (variations of up to 74% and 59%, respectively, within sites). Main sources of variation in greenhouse gas emissions were soil nitrous oxide emissions (58-810g CO2eqCU-1) and soil organic carbon changes (14-720g CO2eqCU-1), while variations in marine eutrophication were mainly explained by field-level waterborne N losses (0.9-8.2g NeqCU-1). The large variation between sites highlights the importance of considering site characteristics when assessing the environmental impact of crop cultivation and evaluating the environmental consequences of crop management practices.

  • 45.
    Henryson, Kajsa
    et al.
    Swedish Univ Agr Sci SLU, Dept Energy & Technol, POB 7032, S-75007 Uppsala, Sweden..
    Hansson, Per-Anders
    Swedish Univ Agr Sci SLU, Dept Energy & Technol, POB 7032, S-75007 Uppsala, Sweden..
    Sundberg, Cecilia
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure. Swedish Univ Agr Sci SLU, Dept Energy & Technol, POB 7032, S-75007 Uppsala, Sweden.
    Spatially differentiated midpoint indicator for marine eutrophication of waterborne emissions in Sweden2018In: The International Journal of Life Cycle Assessment, ISSN 0948-3349, E-ISSN 1614-7502, Vol. 23, no 1, p. 70-81Article in journal (Refereed)
    Abstract [en]

    In life cycle assessment (LCA), eutrophication is commonly assessed using site-generic characterisation factors, despite being a site-dependent environmental impact. The purpose of this study was to improve the environmental relevance of marine eutrophication impact assessment in LCA, particularly regarding the impact assessment of waterborne nutrient emissions from Swedish agriculture. Characterisation factors were derived using site-dependent data on nutrient transport for all agricultural soils in Sweden, divided into 968 catchment areas, and considering the Baltic Sea, the receiving marine compartment, as both nitrogen- and phosphorus-limited. These new characterisation factors were then applied to waterborne nutrient emissions from typical grass ley and spring barley cultivation in all catchments. The site-dependent marine eutrophication characterisation factors obtained for nutrient leaching from soils varied between 0.056 and 0.986 kg N-eq/kg N and between 0 and 7.23 kg N-eq/kg P among sites in Sweden. On applying the new characterisation factors to spring barley and grass ley cultivation at different sites in Sweden, the total marine eutrophication impact from waterborne nutrient emissions for these crops varied by up to two orders of magnitude between sites. This variation shows that site plays an important role in determining the actual impact of an emission, which means that site-dependent impact assessment could provide valuable information to life cycle assessments and increase the relevance of LCA as a tool for assessment of product-related eutrophication impacts. Characterisation factors for marine eutrophication impact assessment at high spatial resolution, considering both the site-dependent fate of eutrophying compounds and specific nutrient limitations in the recipient waterbody, were developed for waterborne nutrient emissions from agriculture in Sweden. Application of the characterisation factors revealed variations in calculated impacts between sites in Sweden, highlighting the importance of spatial differentiation of characterisation modelling within the scale of the impact.

  • 46.
    Henrysson, Maryna
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy Systems.
    Papageorgiou, Asterios
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Björklund, Anna
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment. KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Sustainability Assessment and Management.
    Vanhuyse, Fedra
    Sinha, Rajib
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Monitoring progress towards a circular economy in urban areas: An application of the European Union circular economy monitoring framework in Umeå municipality2022In: Sustainable cities and society, ISSN 2210-6707, Vol. 87, p. 104245-104245, article id 104245Article in journal (Refereed)
    Abstract [en]

    As cities worldwide implement strategies to accelerate the transition toward a circular economy (CE), there is an increasing need for tools to monitor progress. However, a standardised metric for CE monitoring in urban areas is lacking. This study examines the potential of the EU Circular Economy Monitoring Framework (CEMF), an established indicator-based framework for measuring national- and EU-level circularity performance, as a monitoring tool for urban areas. For this purpose, available data sources that can support the framework's application at the urban level are mapped, and data quality is assessed following the pedigree matrix approach. Next, the CEMF indicators are computed for the urban area of Umeå, Sweden. The mapping showed limited availability of urban-level data, necessitating the downscaling of national-level data using proxy factors. Most available urban-level data are of high quality, while the quality of national-level data is reduced when used to compute indicators at the urban level. The application of the CEMF in Umeå indicates that there are areas where the municipality performs well, though further improvements are needed. We conclude that the CEMF has potential as a monitoring tool for urban areas. However, improvements in CEMF...s scope and data availability are recommended.

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  • 47.
    Hu, Jing
    et al.
    Dalian Univ Technol, Sch Hydraul Engn, Dalian 116024, Peoples R China..
    Li, Yu
    Dalian Univ Technol, Sch Hydraul Engn, Dalian 116024, Peoples R China..
    Wörman, Anders
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Zhang, Bingyao
    Dalian Univ Technol, Sch Hydraul Engn, Dalian 116024, Peoples R China..
    Ding, Wei
    Dalian Univ Technol, Sch Hydraul Engn, Dalian 116024, Peoples R China..
    Zhou, Huicheng
    Dalian Univ Technol, Sch Hydraul Engn, Dalian 116024, Peoples R China..
    Reducing energy storage demand by spatial-temporal coordination of multienergy systems2023In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 329, p. 120277-, article id 120277Article in journal (Refereed)
    Abstract [en]

    Utilizing the spatial heterogeneity and climate periodicity of various available renewable energy sources can enhance the multienergy complementarity, which will further reduce the energy storage demand and contributes to the "virtual energy storage gain." In this paper, we propose a spatiotemporal coordination method based on spectral analysis for a wind-PV-hydropower system that targets the maximum virtual energy storage gain. The complementary effect of hydropower on wind and PV power can be seen as changes in the regulation ability resulting from the hydropower construction development as well as a decreased variance in the total system production output. This method is used to determine the optimal coordination distance of multiple energy sources that are matched over different periods representing typical climate variation. A case study in the Yalong River basin in China obtains the best range of hydropower bundling surrounding wind power and PV power stations under different hydropower construction planning scenarios, and it reveals that increased regulation capacity of hydropower will reduce the optimal coordination distance but can achieve more energy balance if both actual storage and virtual storage is accounted for. This approach can realize energy delivery with the optimal coordination distance to meet intensive and efficient development needs, which can provide guidance and support for the planning and construction of wind-PV-hydropower storage systems.

  • 48.
    Hu, Yingtao
    et al.
    Zhejiang Univ, MOE Key Lab Soft Soils & Geoenvironm Engn, Hangzhou 310058, Peoples R China.;Zhejiang Univ, Ctr Hypergrav Expt & Interdisciplinary Res, Hangzhou 310058, Peoples R China..
    Xu, Wenjie
    Zhejiang Univ, MOE Key Lab Soft Soils & Geoenvironm Engn, Hangzhou 310058, Peoples R China.;Zhejiang Univ, Ctr Hypergrav Expt & Interdisciplinary Res, Hangzhou 310058, Peoples R China..
    Zhan, Liangtong
    Zhejiang Univ, MOE Key Lab Soft Soils & Geoenvironm Engn, Hangzhou 310058, Peoples R China.;Zhejiang Univ, Ctr Hypergrav Expt & Interdisciplinary Res, Hangzhou 310058, Peoples R China..
    Zou, Liangchao
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Chen, Yunmin
    Zhejiang Univ, MOE Key Lab Soft Soils & Geoenvironm Engn, Hangzhou 310058, Peoples R China.;Zhejiang Univ, Ctr Hypergrav Expt & Interdisciplinary Res, Hangzhou 310058, Peoples R China..
    Modeling of solute transport in a fracture-matrix system with a three-dimensional discrete fracture network2022In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 605, article id 127333Article in journal (Refereed)
    Abstract [en]

    Understanding the fluid flow and solute transport mechanisms in fractured rocks is essential for many geo-engineering applications. In this study, the fluid flow and solute transport in a fracture-matrix system with a three-dimensional (3-D) discrete fracture network (DFN) are modelled through an efficient numerical simulation workflow. The simulation approach is used to systematically investigate the effects of the rock matrix on the transport behaviors in a fracture-matrix system. The results show that the mass exchange between the DFN and the rock matrix can be accurately evaluated based on the conforming mesh at the interface between the fractures (using triangular elements) and the rock matrix (using tetrahedral elements). The complementary cumulative distribution function curves (CCDFs) for the physical processes that consider sorption and decay exhibit significant long tail characteristics, which suggests that the sorption and decay processes play an important role in retarding the migration of solutes in fractured rocks. It is also found that a larger matrix porosity enhances the mass exchange at the interface between the DFN and the rock matrix, which consequently promotes the matrix diffusion effects. The distribution of the concentration plumes in the matrix demonstrates in fracture-matrix systems with larger fracture densities could result in a better connection between the fracture networks and the larger interface (specific wetting) areas, which therefore, promotes the mass exchange. These findings are critical to understanding the migration behavior of radioactive nuclides in far field areas and for the deep geological disposal of nuclear waste.

  • 49.
    Jaeger, Anna
    et al.
    Department Ecohydrology and Biogeochemistry, Leibniz Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany; Geography Department, Humboldt University Berlin, Berlin, Germany.
    Schaper, Jonas L.
    Department Ecohydrology and Biogeochemistry, Leibniz Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany; Center for Applied Geoscience, Eberhard Karls University of Tübingen, Tübingen, Germany.
    Romeijn, Paul
    School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK.
    Betterle, Andrea
    European Commission, Joint Research Centre, Ispra, Italy; Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland.
    Posselt, Malte
    Department of Environmental Science, Stockholm University, Stockholm, Sweden.
    Krause, Stefan
    School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK; CNRS, ENTPE, UMR5023, Ecologie des Hydrosystèmes Naturels et Anthropisés (LEHNA), University Lyon, Université Claude Bernard Lyon 1, Villeurbanne, France.
    Lewandowski, Jörg
    Department Ecohydrology and Biogeochemistry, Leibniz Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany; Geography Department, Humboldt University Berlin, Berlin, Germany.
    Riml, Joakim
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Time Series of Electrical Conductivity Fluctuations Give Insights Into Long-Term Solute Transport Dynamics of an Urban Stream2023In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 59, no 7, article id e2022WR034203Article in journal (Refereed)
    Abstract [en]

    Artificial tracers are often used for quantitative estimates of solute transport properties in rivers. However, single-injection tracer tests give insights in transport characteristics limited to the ecohydrological conditions at the testing time. Series of time-consuming and laborious tracer tests would be required to properly capture seasonal changes. The present study uses intrinsic diurnal fluctuations of electrical conductivity (EC) caused by discharge of treated wastewater as a tracer to evaluate solute transport processes along a 4.7-km reach of the River Erpe, Germany. By reproducing the fluctuations recorded along the river using the solute transport model one-dimensional transport with inflow and storage, this study investigated the long-term dynamics in solute transport properties. Individual 48-hr curves of EC were used in the steady state configuration of the model to gain 48-hr-integrated estimates of selected transport parameters. Using a sliding window approach in 1-hr steps along the 2,270-hr time series of EC the temporal variability of solute transport between April and June 2016 was assessed. To test the identifiability of parameters using the proposed method, sensitivity analyses and a breakthrough curve analysis of selected 48-hr windows were implemented. With time advancing into the summer, a significant rising trend (Mann-Kendall test p-value < 0.05) of the cross sectional area of the channel was observed and attributed to the growth of macrophytes and a significant slightly decreasing trend for the storage rate was found. The presented method is of high value for river management, as promoting transient storage enhances biogeochemical cycling and benefits water quality.

  • 50.
    Jiang, Xiangang
    et al.
    Sichuan Agr Univ, Coll Civil Engn, Chengdu 611830, Peoples R China.;Sichuan Agr Univ, Sichuan Higher Educ Engn Res Ctr Disaster Prevent, Chengdu 611830, Peoples R China..
    Wörman, Anders
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Chen, Pengshuai
    Sichuan Agr Univ, Coll Civil Engn, Chengdu 611830, Peoples R China..
    Huang, Qin
    Sichuan Agr Univ, Coll Civil Engn, Chengdu 611830, Peoples R China..
    Chen, Huayong
    Chinese Acad Sci, Key Lab Mt Hazards & Earth Surface Proc, Inst Mt Hazards & Environm, Chengdu 610041, Peoples R China.;CAS Ctr Excellence Tibetan Plateau Earth Sci, Beijing 100101, Peoples R China..
    Mechanism of the progressive failure of non-cohesive natural dam slopes2020In: Geomorphology, ISSN 0169-555X, E-ISSN 1872-695X, Vol. 363, article id UNSP 107198Article in journal (Refereed)
    Abstract [en]

    Progressive failure, which begins in the downstream slopes of dams, is one of the main failure modes for natural dams in the field. However, this failure mode lacks attention in the scientific literature, especially regarding its formation mechanism. In this paper, flume tests were conducted to simulate the progressive failure of a natural dam. The results show that the progressive failure process is induced by seepage water discharging on the downstream slope, including the erosion of individual soil particles, repeated minor slip failures, upward head-cutting erosion of the dam crest, and finally the collapse of the dam when the processes have evolved sufficiently. This study focuses on analyzing the initiation mechanism of soil particle migration. The influence of seepage and interflow stresses on the incipient erosion of soil particles is analyzed. In addition, the buoyancy of soil particles on the downstream slope surface is not considered in the vertical direction in this paper but in the direction perpendicular to the downstream slope surface. The paper also discusses how to estimate the occurrence of the progressive failure of a natural dam. In the estimation method, the stress of the interfacial flow, the seepage flow stress, and the friction stress of the soil particles are considered when the phreatic line reaches the downstream slope surface.

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