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  • 1.
    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, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    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 rivers2018Ingår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, artikel-id 17232Artikel i tidskrift (Refereegranskat)
    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.

  • 2.
    Cvetkovic, Vladimir
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Statistical Formulation of Generalized Tracer Retention in Fractured Rock2017Ingår i: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 53, nr 11, s. 8736-8759Artikel i tidskrift (Refereegranskat)
    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.

  • 3. Eriksson, Helen
    et al.
    Johansson, Tim
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Olsson, Per-Ola
    Andersson, Maria
    Engvall, Jakob
    Hast, Isak
    Harrie, Lars
    Requirements, Development, and Evaluation of A National Building Standard-A Swedish Case Study2020Ingår i: ISPRS International Journal of Geo-Information, ISSN 2220-9964, Vol. 9, nr 2, artikel-id 78Artikel i tidskrift (Refereegranskat)
    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.

  • 4.
    Ermolaev, Evgheni
    et al.
    Swedish Univ Agr Sci SLU, Dept Energy & Technol, Box 7032, SE-75007 Uppsala, Sweden..
    Sundberg, Cecilia
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur. 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 composting2019Ingår i: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 240, artikel-id UNSP 118165Artikel i tidskrift (Refereegranskat)
    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.

  • 5.
    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, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    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 Bangladesh2018Ingår i: Hydrology and Earth System Sciences, ISSN 1027-5606, E-ISSN 1607-7938, Vol. 22, nr 10, s. 5159-5173Artikel i tidskrift (Refereegranskat)
    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.

  • 6.
    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, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Dagan, Gedeon
    Tel Aviv Univ, Sch Mech Engn, Ramat Aviv, Israel..
    Groundwater Contaminant Transport: Prediction Under Uncertainty, With Application to the MADE Transport Experiment2019Ingår i: FRONTIERS IN ENVIRONMENTAL SCIENCE, ISSN 2296-665X, Vol. 7, artikel-id 79Artikel i tidskrift (Refereegranskat)
    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.

  • 7.
    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, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    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 Households2019Ingår i: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 12, nr 22, artikel-id 4285Artikel i tidskrift (Refereegranskat)
    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.

  • 8.
    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, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur. 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 Kenya2019Ingår i: Energy for Sustainable Development, ISSN 0973-0826, Vol. 52, s. 63-71Artikel i tidskrift (Refereegranskat)
    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.

  • 9.
    Hamisi, Rajabu
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Vatten- och miljöteknik.
    Renman, Gunno
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Vatten- och miljöteknik.
    Renman, Agnieszka
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Vatten- och miljöteknik.
    Wörman, Anders
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Modelling Phosphorus Sorption Kinetics and the Longevity of Reactive Filter Materials Used for On-site Wastewater Treatment2019Ingår i: Water, Vol. 11, nr 4, artikel-id 811Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Use of reactive filter media (RFM) is an emerging technology in small-scale wastewater treatment to improve phosphorus (P) removal and filter material longevity for making this technology sustainable. In this study, long-term sorption kinetics and the spatial dynamics of sorbed P distribution were simulated in replaceable P-filter bags filled with 700 L of reactive material and used in real on-site treatment systems. The input data for model calibration were obtained in laboratory trials with Filtralite P®, Polonite® and Top16. The P concentration breakthrough threshold value was set at an effluent/influent (C/C0) ratio of 1 and simulations were performed with P concentrations varying from 1 to 25 mg L−1. The simulation results showed that influent P concentration was important for the breakthrough and longevity, and that Polonite performed best, followed by Top16 and Filtralite P. A 100-day break in simulated intermittent flow allowed the materials to recover, which for Polonite involved slight retardation of P saturation. The simulated spatial distribution of P accumulated in the filter bags showed large differences between the filter materials. The modelling insights from this study can be applied in design and operation of on-site treatment systems using reactive filter materials

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  • 10.
    Hamisi, Rajabu
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Vatten- och miljöteknik.
    Renman, Gunno
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Vatten- och miljöteknik.
    Renman, Agnieszka
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Vatten- och miljöteknik.
    Wörman, Anders
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Phosphorus sorption and leaching in sand filters used for onsite wastewater treatment - a column experimentIngår i: Artikel, recension (Refereegranskat)
    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.

  • 11.
    Hamisi, Rajabu
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Vatten- och miljöteknik.
    Renman, Gunno
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Vatten- och miljöteknik.
    Renman, Agnieszka
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Vatten- och miljöteknik.
    Wörman, Anders
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Simulating the hydraulic dynamics and treatment performance of a sequencing batch flow constructed wetlandIngår i: Artikel, recension (Refereegranskat)
    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.

  • 12.
    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, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Environmental performance of crop cultivation at different sites and nitrogen rates in Sweden2019Ingår i: Nutrient Cycling in Agroecosystems, ISSN 1385-1314, E-ISSN 1573-0867, Vol. 114, nr 2, s. 139-155Artikel i tidskrift (Refereegranskat)
    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.

  • 13.
    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, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur. 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 Sweden2018Ingår i: The International Journal of Life Cycle Assessment, ISSN 0948-3349, E-ISSN 1614-7502, Vol. 23, nr 1, s. 70-81Artikel i tidskrift (Refereegranskat)
    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.

  • 14.
    Kivimaa, Paula
    et al.
    Science Policy Research Unit SPRU, University of Sussex; Finnish Environment Institute.
    Kangas, Hanna-Liisa
    Finnish Environment Institute.
    Lazarevic, David
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur. Finnish Environment Institute.
    Client-oriented evaluation of ‘creative destruction’in policy mixes: Finnish policies on building energy efficiency transition2017Ingår i: Energy Research & Social Science, Vol. 33, s. 115-127Artikel i tidskrift (Refereegranskat)
  • 15.
    Kordas, Olga
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Gourjii, A.
    Nikiforovich, E.
    Cherniy, D.
    A study on mathematical short-term modelling of environmental pollutant transport by sea currents: The lagrangian approach2017Ingår i: Journal of Environmental Accounting and Management, ISSN 2325-6192, E-ISSN 2325-6206, Vol. 5, nr 2, s. 87-104Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper deals with short-term modelling of pollutant transport on the sea surface after environmental accidents. Using the Lagrangian approach, a two-dimensional model of pollutant flow is developed to determine the average velocity field of the flow in the presence of tidal currents and sea surface wind stress for an arbitrarily shaped coastline. This approach assumes that the main transport mechanism is convection. Short-term scenarios are considered, where diffusion effects on pollutant transport can be neglected. The hydrodynamic problem is solved by the method of discrete singularities adapted to fluid advection problems. The problem of environmental pollutant transport by sea currents is reduced to integration of the advection equations to determine the spatio-temporal properties of the spreading pollution. The model was verified through comparison of the results against natural observations on the spread of an oil spill on the sea surface following a collision between the Chinese bulk carrier Fu Shan Hai and the Cyprian container ship Gdynia near the island of Bornholm in the Baltic Sea (May 31, 2003). Satisfactory agreement was found between results of a 7-day numerical simulation and observed data. The proposed model can therefore be used for real-time prediction of short-term pollutant transport on a sea surface with an arbitrarily shaped coastline, to support decision-making processes during maritime accidents, in particular oil spills.

  • 16.
    Lazarevic, David
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur. Finnish Environment Institute, Environmental Policy Centre, Finland.
    Valve, Helena
    Narrating expectations for the circular economy: towards a common and contested European transition2017Ingår i: Energy Research & Social Science, ISSN 2214-6296, E-ISSN 2214-6326, Vol. 31, s. 60-69Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The European Union (EU) has set its sights on becoming a circular economy, envisaging a transition that implies systemic changes in natural resource transformations and material flows; and offering a response to what is commonly labelled as the ‘take-make-dispose’ conventional economic model. What does the transition toward a circular economy entail and what can it do? This paper analyses the emergence and mobilisation of expectations that are shaping the EU transition to a circular economy. It traces the narrative elements through which the circular economy is configured through an analysis of position papers presented to inform the debate on the European Commission’s circular economy package. Expectations for the circular economy are articulated as: (1) a perfect circle of slow material flows; (2) a shift from consumer to user; (3) growth through circularity and decoupling; and (4) a solution to European renewal. Extending boundaries of what is ‘in’ benefits actors driving the circular economy as, in the short-term, they can actively support a deliberately vague, but uncontroversial, circular economy. On the one hand, the expectations present a strong sense of a collective ‘we’, on the other hand we are yet to see the contentions and contestations being full playing out

  • 17.
    Levi, Lea
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Cvetkovic, Vladimir
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Destouni, Georgia
    Data-driven analysis of nutrient inputs and transfers through nested catchments2018Ingår i: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 610, s. 482-494Artikel i tidskrift (Refereegranskat)
  • 18.
    Lewandowski, Joerg
    et al.
    Leibniz Inst Freshwater Ecol & Inland Fisheries, Dept Ecohydrol, D-12587 Berlin, Germany.;Humboldt Univ, Geog Dept, D-12489 Berlin, Germany..
    Mojarrad, Babak Brian
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Wu, Liwen
    Leibniz Inst Freshwater Ecol & Inland Fisheries, Dept Ecohydrol, D-12587 Berlin, Germany.;Humboldt Univ, Geog Dept, D-12489 Berlin, Germany..
    Is the Hyporheic Zone Relevant beyond the Scientific Community?2019Ingår i: Water, ISSN 2073-4441, E-ISSN 2073-4441, Vol. 11, nr 11, artikel-id 2230Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Rivers are important ecosystems under continuous anthropogenic stresses. The hyporheic zone is a ubiquitous, reactive interface between the main channel and its surrounding sediments along the river network. We elaborate on the main physical, biological, and biogeochemical drivers and processes within the hyporheic zone that have been studied by multiple scientific disciplines for almost half a century. These previous efforts have shown that the hyporheic zone is a modulator for most metabolic stream processes and serves as a refuge and habitat for a diverse range of aquatic organisms. It also exerts a major control on river water quality by increasing the contact time with reactive environments, which in turn results in retention and transformation of nutrients, trace organic compounds, fine suspended particles, and microplastics, among others. The paper showcases the critical importance of hyporheic zones, both from a scientific and an applied perspective, and their role in ecosystem services to answer the question of the manuscript title. It identifies major research gaps in our understanding of hyporheic processes. In conclusion, we highlight the potential of hyporheic restoration to efficiently manage and reactivate ecosystem functions and services in river corridors.

  • 19. Li, B.
    et al.
    Mo, Y.
    Zou, Liangchao
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Liu, R.
    Cvetkovic, V.
    Influence of surface roughness on fluid flow and solute transport through 3D crossed rock fractures2020Ingår i: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 582, artikel-id 124284Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The influence of surface roughness on fluid flow and solute transport through three-dimensional (3D) crossed rock fractures are investigated by numerical simulations. Three crossed fracture models with different degrees of surface roughness are established by two intersecting rough-walled fractures with four branches. The fracture surface morphological data are measured from three natural fractures in sandstone and granite rock samples. The fluid flow is simulated by solving the Navier-Stokes equations and solute transport is simulated by solving the advective-diffusion equation. By rotating one fracture plane while fixing the other, series of intersection models with different angles between the two crossed fractures are established to investigate the influence of the intersecting angle. Simulation results of the rough-walled fractures are compared with the smooth parallel-plate model, showing that the surface roughness significantly enhances channeling and mixing for fluid flow and solute transport at fracture intersections. The mechanism is that the complex geometry of the intersection for rough-walled models results in reallocation of fluid pathways at the intersection, which consequently affect the mixing behavior depending on the Peclet number. The intersecting angle affects the channeling and mixing behavior because it influences the geometrical structure of the fracture intersection. The correlation between the mixing ratio and the geometrical characteristics of intersections is quantified by a relative roughness parameter. The results reveal that the widely adopted smooth parallel-plate model may lead to significant uncertainty in predicting the solute transport in crossed fractures, especially at intersections with unmated fracture surfaces. The correlation between the mixing ratio and the roughness parameter developed in this study can be incorporated into discrete fracture network models to improve their performance in estimating solute transport in fractured rocks.

  • 20.
    Li, Shicheng
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Betongbyggnad.
    Li, Qiulin
    Chongqing Jiaotong Univ, Southwest Sci Res Inst Water Transport Engn, Chongqing 400016, Peoples R China..
    Yang, James
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    CFD Modelling of a Stepped Spillway with Various Step Layouts2019Ingår i: Mathematical problems in engineering (Print), ISSN 1024-123X, E-ISSN 1563-5147, Vol. 2019, artikel-id 6215739Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A traditional stepped spillway is prone to cavitation risks. To improve its hydraulic behaviors, distorted step faces and pool weirs are devised. By numerical modelling, comparative studies are conducted to look into the flow features. The pressures on step surfaces of the unconventional layouts exhibit 3D distributions. Pool weirs are essential in increasing both the min. and max. pressure loads. Pressures on the downstream bed show a unique pattern for V- and inverted V-shaped models, with the extreme pressures at the sidewalls for the former and at the central plane for the latter. Symmetrical secondary flows are formed in V- and inverted V-shaped cases with different patterns. Distributions of turbulent kinetic energy suggest differences in flow motions in all cases. Furthermore, the relative energy loss of flat setups is similar to 5.4% lower than that of the pooled ones with the same step face angle; inverting the face angle does not give rise to noticeable change. The results provide reference for relevant projects.

  • 21. Lin, C.
    et al.
    Kao, M. -J
    Yang, James
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Teng, P. -H
    Raikar, R. V.
    Study on probabilistic mean features of lower and upper free-surface profiles and velocity fields of a highly fluctuating free jet over a chute2018Ingår i: Journal of Marine Science and Technology (Taiwan), ISSN 1023-2796, Vol. 26, nr 3, s. 309-326Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An optic-based method that utilizes the particle-laden images captured during high-speed particle image velocimetry (HSPIV) measurements is presented, aiming to explore the probabilistic mean characteristics of the free surface profiles and velocity fields of a free jet with high-frequency random fluctuations over a chute. The technique based on the gray-level gradients in the smoothed gray level distribution of the contrast-enhanced images is used to determine the probabilistic mean features of the free jet, right beneath and above which the water-air interfaces have I%/(100 I)% intermittent appearance of air/water phase and (100 I)% /I% fitful show-up of water/air phase. Further, the cross-correlation calculation for HSPIV measurements is employed to obtain the instantaneous and probabilistic mean velocity fields of the free jet. A target experiment of the free jet having a mean water-depth of 2.76 cm and a Froude number of 3.92 over a 17 chute model is performed in a re-circulating water channel to demonstrate the application of this method. The entire process for obtaining the probabilistic mean positions of the free surface profiles is elucidated step-by step. The lower/upper part of the free surface changing from the height at which the possibility of intermittent appearance of water phase is 3%/97%, via the counterpart for 50%/50%, to that for 97%/ 3% is identified precisely. In addition, the probabilistic mean velocity field is further categorized into the conditionally and overall time-averaged ones. Each streamwise velocity profile in the conditionally time-averaged velocity field is fairly uniform. However, the counterpart in the overall time-averaged velocity field evidently shows the non-uniform feature with prominent velocity gradient in the lower/upper part between the height at which the possibility of intermittent appearance of water phase is 3%/97% and the counterpart is 97%/3%.

  • 22. Maranghi, S.
    et al.
    Parisi, M. L.
    Facchini, A.
    Rubino, A.
    Kordas, Olga
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Basosi, R.
    Integrating urban metabolism and life cycle assessment to analyse urban sustainability2020Ingår i: Ecological Indicators, ISSN 1470-160X, E-ISSN 1872-7034, Vol. 112, artikel-id 106074Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In recent decades, the close correlation between urban development and the concept of sustainability has become increasingly evident and important. This is demonstrated by European Union policies concerning EU cities and the United Nations 2030 Agenda for Sustainable Development, including sustainable development goal (SDG) 11: Sustainable cities and communities. In the context of increasing urbanization, it is essential to find innovative methods to manage urban living systems and to establish a standard method for assessing the environmental performance of cities and their infrastructures. A unified and complete methodology for assessing policies for urban sustainability that takes into consideration urban complexity is currently lacking. In this paper, we integrate the Urban Metabolism and Lice Cycle Assessment approach to assess urban sustainability by developing a multi-dimensional measure framework applied to cities. Our aim is to provide a holistic view of the city and unveiling the interconnections among a set of urban dimensions identified by means of an approach based on complex systems science and complex networks. We also propose a specific survey to investigate the city in a multi-dimensional perspective and suggest key indicators based on network centrality measures for investigating and comparing the interconnections among a set of urban dimensions specifically identified (e.g. energy, material, transport). Finally, a case study based on Beijing is considered to show potential applications.

  • 23.
    Molinari, Marco
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Kordas, Olga
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    ICT in the built environment: drivers, barriers and uncertainties2017Ingår i: Biennial International Workshop Advances in Energy Studies: BIWAES, Graz, 2017Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Buildings are major contributors to energy use and environmental impact in developed societies. If theambitious sustainability targets of modern societies are to be met, energy use in the built environmentmust be addressed as a central issue.New momentum on achieving energy efficiency in the building sector has been triggered by informationand communication technology (ICT). New opportunities bringing the concept of smart building closerto reality are offered e.g. by innovative sensing techniques, extensive and cost-efficient data collectionand analysis, advanced controls and artificial intelligence.However, these opportunities are associated with cost and uncertainties regarding whether theinvestment costs are paid back in terms of energy savings, whether indoor comfort and air quality andimproved, the drawbacks in term of increased maintenance effort, complexity, reliability and resilience,the effects in terms of user interaction, how data security is affected and the long-term effects on society.This paper critically analyses recent research findings and reviews the pros and cons of some promisingICT techniques being applied in the building sector. It exemplifies drivers and barriers to implementationof advanced controls and artificial intelligence in buildings, based on findings from two test-beds inStockholm, and discusses the implications of these findings for future research.

  • 24.
    Nilsson, Anders
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Stoll, Pia
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    Brandt, Nils
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    Assessing the impact of real-time price visualization on residential electricity consumption, costs, and carbon emissions2015Ingår i: Resources, Conservation and Recycling, ISSN 0921-3449, E-ISSN 1879-0658, Vol. 124, s. 152-161Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The development of smart grid projects, with demand side management as an integral part, has led to an increased interest of households’ willingness to react to different types of demand response programs. This paper presents a pilot study assessing the impact of real-time price visualization on residential electricity consumption, and its effects on electricity costs and carbon (CO2eq) emissions. We analyze changes in electricity consumption based on a test group and a reference group of 12 households, respectively. To allow for analysis on load shift impact on CO2eq emissions, hourly dynamic CO2eq intensity of the Swedish electricity grid mix is calculated, using electricity generation data, trading data, and fuel-type specific emission factors. The results suggest that, on average, the test households shifted roughly 5% of their total daily electricity consumption from peak hours (of high electricity price) to off-peak hours (of low electricity price) as an effect of real-time price visualization. However, due to the mechanisms of the Swedish electricity market, with a negative relation between spot price and CO2eq intensity, the load shift led to a split effect; electricity costs modestly decreased while CO2eq emissions increased. In addition, any indication of the contribution of real-time spot price visualization to a reduction in overall household electricity consumption level could not be found, as the relative difference in consumption level between the test households and the reference households remained constant during both the baseline period and the test period. 

  • 25.
    Nilsson, Anders
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Wester, Misse
    Lazarevic, David
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    Brandt, Nils
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    Smart homes, home energy management systems and real-time feedback- Lessons for influencing household energy consumption from a Swedish field study2018Ingår i: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 179, s. 15-25Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Home energy management systems (HEMS), providing energy feedback and smart features through in-home displays, have the potential to support more sustainable household decisions concerning energy consumption. However, recent findings from European smart metering trials have reduced the optimism, suggesting only modest savings from energy feedback. In this paper, we investigate the potential of HEMS to foster reductions in energy use, focusing on a population segment of particular relevance; high-income and highly educated households, considered as early adopters of smart grid technologies. Covering 154 households participating in a field trial in a sustainable city district in Stockholm, Sweden during one year, this study draws on the analyses of smart meter electricity and hot tap water data and in-depth interviews to provide an increased understanding of how feedback and features are perceived, used, and acted upon, and resulting effects on awareness, behavior, and consumption. Our results show that impact on energy consumption varies widely across individual households, suggesting that households respond to energy feedback highly individually. Although HEMS may lead to increased awareness of energy consumption, as well as increased home comfort, several obstacles for energy consumption behavioral change are identified. Drawing from these findings, we suggest policy implications and key issues for future research.

  • 26.
    Papageorgiou, Asterios
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Sinha, Rajib
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    Frostell, B.
    Sundberg, Cecilia
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    A new physical accounting model for material flows in urban systems with application to the Stockholm Royal Seaport District2019Ingår i: Journal of Industrial Ecology, ISSN 1088-1980, E-ISSN 1530-9290Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Sustainable urbanization requires streamlining of resource management in urban systems which in turn requires understanding of urban metabolism (UM). Even though various methods have been applied for UM analysis, to date there is no standardized method for comprehensive accounting of material flows in urban systems. Moreover, the accounting of material flows is rarely implemented with a bottom-up approach that can provide a thorough analysis of UM. This article presents the Urban Accounting Model (UAM) which aims to allow comprehensive accounting of urban material flows based on a bottom-up approach. The model comprises two interlinked sub-models. The first was developed by integrating a new physical input output table (PIOT) framework for urban systems into a three-dimensional structure. The second comprises a set of physical accounts for systematic accounting of material flows of each economic sector in the system in order to support the compilation of the PIOTs. The functions of the UAM were explored through its application to two urban neighborhoods in the Stockholm Royal Seaport district. The application highlighted that the UAM can describe the physical interactions between the urban system and the environment or other socioeconomic systems, and capture the intersectoral flows within the system. Moreover, its accounts provide information that allow an in-depth analysis of the metabolism of specific sectors. Overall, the UAM can function as a useful tool for UM analysis as it systematizes data collection and at the same time depicts the physical reality of the urban system.

  • 27.
    Pasichnyi, Oleksii
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Levihn, Fabian
    KTH, Skolan för industriell teknik och management (ITM), Industriell ekonomi och organisation (Inst.), Hållbarhet och industriell dynamik.
    Shahrokni, Hossein
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    Wallin, Jörgen
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik. KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Uthålliga byggnadssystem. KTH Royal Inst Technol, Dept Energy Technol ETT, Res Grp Urban Analyt & Transit UrbanT, Brinellvagen 68, S-10144 Stockholm, Sweden..
    Kordas, Olga
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik. KTH Royal Inst Technol, Dept Sustainable Dev Environm Sci & Engn SEED, Res Grp Urban Analyt & Transit UrbanT, Tekn Ringen 10b, S-10044 Stockholm, Sweden..
    Data-driven strategic planning of building energy retrofitting: The case of Stockholm2019Ingår i: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 233, s. 546-560Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Limiting global warming to 1.5 degrees C requires a substantial decrease in the average carbon intensity of buildings, which implies a need for decision-support systems to enable large-scale energy efficiency improvements in existing building stock. This paper presents a novel data-driven approach to strategic planning of building energy retrofitting. The approach is based on the urban building energy model (UBEM), using data about actual building heat energy consumption, energy performance certificates and reference databases. Aggregated projections of the energy performance of each building are used for holistic city-level analysis of retrofitting strategies considering multiple objectives, such as energy saving, emissions reduction and required social investment. The approach is illustrated by the case of Stockholm, where three retrofitting packages (heat recovery ventilation; energy-efficient windows; and a combination of these) were considered for multi-family residential buildings constructed 1946-1975. This identified potential for decreasing heat demand by 334 GWh (18%) and consequent emissions reduction by 19.6 kt-CO2 per year. The proposed method allows the change in total energy demand from large-scale retrofitting to be assessed and explores its impact on the supply side. It thus enables more precisely targeted and better coordinated energy efficiency programmes. The case of Stockholm demonstrates the potential of rich urban energy datasets and data science techniques for better decision making and strategic planning.

  • 28.
    Pasichnyi, Oleksii
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Wallin, Jörgen
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Kordas, Olga
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Data-driven building archetypes for urban building energy modelling2019Ingår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 181, s. 360-377Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents an approach for using rich datasets to develop different building archetypes depending on the urban energy challenges addressed. Two cases (building retrofitting and electric heating) were analysed using the same city, Stockholm (Sweden), and the same input data, energy performance certificates and heat energy use metering data. The distinctive character of these problems resulted in different modelling workflows and archetypes being developed. The building retrofitting case followed a hybrid approach, integrating statistical and physical perspectives, estimating energy savings for 5532 buildings from seven retrofitting packages. The electric heating case provided an explicitly statistical data-driven view of the problem, estimating potential for improvement of power capacity of the local electric grid at peak electric power of 147 MW. The conclusion was that the growing availability of linked building energy data requires a shift in the urban building energy modelling (UBEM) paradigm from single-logic models to on-request multiple-purpose data intelligence services.

  • 29.
    Pasichnyi, Oleksii
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Wallin, Jörgen
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Levihn, Fabian
    KTH, Skolan för industriell teknik och management (ITM), Industriell ekonomi och organisation (Inst.). AB Stockholm Exergi, Sweden.
    Shahrokni, Hossein
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    Kordas, Olga
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    Energy performance certificates — New opportunities for data-enabled urban energy policy instruments?2019Ingår i: Energy Policy, ISSN 0301-4215, E-ISSN 1873-6777, s. 486-499Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Energy performance certificates (EPC) were introduced in European Union to support reaching energy efficiency targets by informing actors in the building sector about energy efficiency in buildings. While EPC have become a core source of information about building energy, the domains of its applications have not been studied systematically. This partly explains the limitation of conventional EPC data quality studies that fail to expose the essential problems and secure effective use of the data. This study reviews existing applications of EPC data and proposes a new method for assessing the quality of EPCs using data analytics. Thirteen application domains were identified from systematic mapping of 79 papers, revealing increases in the number and complexity of studies and advances in applied data analysis techniques. The proposed data quality assurance method based on six validation levels was tested using four samples of EPC dataset for the case of Sweden. The analysis showed that EPC data can be improved through adding or revising the EPC features and assuring interoperability of EPC datasets. In conclusion, EPC data have wider applications than initially intended by the EPC policy instrument, placing stronger requirements on the quality and content of the data.

  • 30.
    Pereverza, Kateryna
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Steering sustainability transitions? Modular participatory backcasting for strategic planning in the heating and cooling sector2019Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Det är både angeläget och brådskande att främja hållbara omställningsprocesser för värme och kyla inom energisektorn. Det finns olika styrmekanismer som kan möjliggöra samordning av olika aktörers insatser mot gemensamma hållbarhetsmål inom sektorn. Tidigare studier har identifierat relevanta krav för styrning av ett ramverk för detta, men de har då inte specifikt behandlat styrning inom värme och kyla. Deltagande backcasting (eng. participatory backcasting, PB) har ett antal relevanta egenskaper för att kunna användas som just ett sådant ramverk för planering inom området. Däremot behöver användning av PB i sektorn utvärderas med avseende på lokal anpassningsbarhet och användbarhet.

    Den här avhandling syftar till att vidareutveckla strategisk planering för området värme och kyla genom att öka anpassningsbarheten, transparensen och reflixiviteten av PB-processer samt genom att utvidga ramverkets påverkan till ett vidare sammanhang (än de individer som är direkt berörda). De huvudsakliga forskningsmålen var att: (1) utveckla ett strategiskt ramverk för planering för området värme och kyla baserad på PB och att undersöka hur anpassningsbart ramverket är i förhållande till lokala förutsättningar; (2) utforska metoder för utveckling, urval och analys av scenarier som möjliggör informationsöverföring mellan modellering och deltagandeprocesser inom strategisk planering baserad på PB; och (3) identifiera faktorer som kan sprida påverkan bortom de individer som är direkt involverade i deltagandeprocesserna.

    Mål 1 och 2 har behandlats i en flerfallstudie som omfattar tvärvetenskaplig forskning över ett års tid, PB-baserade planeringsprocesser i Bila Tserkva, Ukraina (Fall I) och Niš, Serbien (Fall II). De vidare effekterna av deltagandeprocesserna studerades i en fallstudie i Sverige där projektet syftade till att vidareutveckla praktiken för långsiktig planering i regioner, framsynsprocessen ”Region 2050” (Fall III). I samtliga fall kombinerades teoretisk och empirisk forskning.

    Studien föreslår ett nytt ramverk, modulär deltagande backcasting (mPB), för strategisk planering inom värme och kyla. Ramverket integrerar principer för modularitet, deltagandemodellering och tvärvetenskaplighet. Implementering av modulär deltagande backcasting (mPB) visar godtagbar lokal anpassningsbarhet vid användning i både Fall I och Fall II. Genom utveckling av en morfologisk metod samt införandet av deltagande modelleringsprocesser uppnåddes en högre grad av reflexivitet och ökad transparens i de PB-baserade planeringsprocesserna för scenarioutveckling, scenariourval och scenarioanalys. Slutligen identifierades faktorer som gränsgöverskidare (eng. boundary spanning individuals), samarbeten och institutionell mångfald som viktiga för att bredda PB-processens effekter i ett vidare sammanhang.

    Ladda ner fulltext (pdf)
    Ph D Thesis
  • 31.
    Pereverza, Kateryna
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Kordas, Olga
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Sustainability through stakeholder learning: Participatory backcasting for the heating sector2017Ingår i: 10th BIWAES Biennial International Workshop Advances in Energy Studies: Energy futures, environment and well-being / [ed] Sergio Ulgiati and Laura Vanoli, Budapest, 2017Konferensbidrag (Refereegranskat)
    Abstract [en]

    Social learning is an important element of the reflexive governance approaches needed to enable sustainability transitions. One such approach is participatory backcasting (PB), which involves development of a desirable future vision and a pathway towards this vision. Social learning has been reported as an outcome of different PB projects, including those performed in the infrastructure sector. This study examined the importance of sharing and transferring knowledge and new perceptions developed during PB projects among the individuals directly involved in these projects to and within their formal and informal groups and organisations (e.g. local authorities, DH companies, equipment producers, consumer associations). Mechanisms that need to be incorporated into PB processes to support knowledge sharing/transfer were identified as: (1) use of actor role profiles to identify individuals with bridging/connecting/change agent capability for inclusion in a PB process; (2) strong participant engagement in co-creation activities during the PB project; and (3) PB process design to achieve the multiplier effect (e.g. capacity-building workshops for local researchers and authorities). These mechanisms were successfully tested using the case of two PB-based projects seeking sustainability in the heating sector of the Ukrainian city Bila Tserkva and the Serbian city Niš. It was concluded that further investigation of mechanisms for knowledge sharing/transfer and experimentation within PB processes is a promising research area for enabling sustainability transitions in the heating sector.

  • 32.
    Rasul, Hedi
    et al.
    Koya University.
    Zou, Liangchao
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Olofsson, Bo
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Vatten- och miljöteknik.
    Monitoring of moisture and salinity content in an operational road structure by electrical resistivity tomography.Ingår i: Near Surface Geophysics, ISSN 1569-4445, E-ISSN 1873-0604Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Moisture dynamics in road systems significantly affect road structure design and maintenance. This study analysed moisture dynamics in a cross-section of motorway (the E18) in Sweden during a one-year period through in situ monitoring using electrical resistivity tomography (ERT). The monitoring methodology was assessed since resistivity can provide a good proxy for monitoring moisture in the road structure. Monthly electrical resistivity was calculated by inverting resistivity data along a pre-installed electrical resistivity line beneath the surface asphalt layer of the road at the test site. The electrical resistivity data were then statistically analysed and correlated with local climate data, i.e. precipitation and temperature, and with ground parameters such as moisture content. The results showed high variation in resistivity in the road surface layer and road shoulders depending on weather conditions, water flow and other surface activities. In general, negative correlations between electrical resistivity and precipitation were observed. The results also indicated possible retardation of de-icing salt after accumulating in the top layer during winter. These findings advance understanding of the moisture dynamics in roads and can help improve pavement design in response to future climate change.

  • 33.
    Refsgaard, Jens Christian
    et al.
    Geol Survey Denmark & Greenland, Copenhagen, Denmark..
    Hansen, Anne L.
    LandboSyd, Aabenraa, Denmark..
    Hojberg, Anker L.
    Geol Survey Denmark & Greenland, Copenhagen, Denmark..
    Olesen, Jorgen E.
    Aarhus Univ, Dept Agroecol, Tjele, Denmark..
    Hashemi, Fatemeh
    Aarhus Univ, Dept Biosci, Silkeborg, Denmark..
    Wachniew, Przemyslaw
    AGH Univ Sci & Technol, Krakow, Poland..
    Wörman, Anders
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Bartosova, Alena
    Swedish Meteorol & Hydrol Inst, Norrkoping, Sweden..
    Stelljes, Nico
    Ecol Inst, Berlin, Germany..
    Chubarenko, Boris
    Russian Acad Sci, Shirshov Inst Oceanol, Moscow, Russia..
    Spatially differentiated regulation: Can it save the Baltic Sea from excessive N-loads?2019Ingår i: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 48, nr 11, s. 1278-1289Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Baltic Sea Action Plan and the EU Water Framework Directive both require substantial additional reductions of nutrient loads (N and P) to the marine environment. Focusing on nitrogen, we present a widely applicable concept for spatially differentiated regulation, exploiting the large spatial variations in the natural removal of nitrate in groundwater and surface water. By targeting mitigation measures towards areas where nature's own capacity for removal is low, spatially differentiated regulation can be more cost-effective than the traditional uniform regulation. We present a methodology for upscaling local modelling results on targeted measures at field scale to Baltic Sea drainage basin scale. The paper assesses the potential gain and discusses key challenges related to implementation of spatially differentiated regulation, including the need for more scientific knowledge, handling of uncertainties, practical constraints related to agricultural practice and introduction of co-governance regimes.

  • 34.
    Ríos Bayona, Francisco
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Jord- och bergmekanik.
    Stigsson, Martin
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur. SKB, Swedish Nuclear Fuel and Waste Management Co.
    Johansson, Fredrik
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Jord- och bergmekanik.
    Mas Ivars, Diego
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Jord- och bergmekanik. SKB, Swedish Nuclear Fuel and Waste Management Co.
    Comparison between shear strength based on Barton’s roughness profiles and equivalent synthetic profiles based on fractal theory2018Ingår i: 52nd U.S. Rock Mechanics/Geomechanics Symposium, American Rock Mechanics Association (ARMA) , 2018Konferensbidrag (Refereegranskat)
    Abstract [en]

    A comprehensive understanding of the shear strength and the mechanical behavior of rock joints is to some extent still missing today. Several attempts have been made to develop empirical and analytical shear strength criteria that explain this mechanism. One of the most important parameters governing the shear strength of rock fractures is the surface roughness, which is generally determined using the Joint Roughness Coefficient (JRC). This parameter is often determined subjectively in the field by comparison with 10 predefined roughness profiles. Recent studies indicate that surface roughness can be accurately represented by using fractal analysis. The aim of this study is to perform a first attempt to investigate the mechanical equivalence in terms of the peak shear strength between synthetic rock fractures, where the surface roughness has been generated using fractal theory, and standard roughness profiles from Barton and Choubey, 1977, using the particle flow code PFC2D. The results from the numerical shear tests under constant normal load (CNL) are compared with the predicted peak shear strength using Barton’s criterion and a back-calculation of the JRC value is carried out.

  • 35.
    Shamu, John
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Jord- och bergmekanik.
    Zou, Liangchao
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Håkansson, Ulf
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Jord- och bergmekanik. Skanska Sweden AB.
    Cementbaserade Injekteringsmedels Reogram: Instabilt Flöde Och Inverkan På Injektering2019Ingår i: Proceedings Bergdagarna 2019, Stockholm, 2019Konferensbidrag (Övrigt vetenskapligt)
  • 36.
    Shamu, John
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Jord- och bergmekanik.
    Zou, Liangchao
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Kotzé, Reinhardt
    Incipientus Ultrasound Flow Technologies AB, Sweden.
    Wiklund, Johan
    Incipientus Ultrasound Flow Technologies AB, Sweden.
    Håkansson, Ulf
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Jord- och bergmekanik. Skanska Sweden AB, Sweden.
    Radial Flow Velocity Profiles of a Yield Stress Fluid between Smooth Parallel Disks2020Ingår i: Rheologica Acta, ISSN 0035-4511, E-ISSN 1435-1528Artikel i tidskrift (Refereegranskat)
    Ladda ner fulltext (pdf)
    fulltext
  • 37.
    Soltani, Safeyeh
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Cvetkovic, Vladimir
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Quantifying the distribution of tracer discharge from boreal catchments under transient flow using the kinematic pathway approach2017Ingår i: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 53, nr 7, s. 5659-5676Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This focuses on solute discharge from boreal catchments with relatively shallow groundwater table and topography-driven groundwater flow. We explore whether a simplified semianalytical approach can be used for predictive modeling of the statistical distribution of tracer discharge. The approach is referred to as the "kinematic pathways approach'' (KPA). This approach uses hydrological and tracer inputs and topographical and hydrogeological information; the latter regards average aquifer depth to the less permeable bedrock. A characteristic velocity of water flow through the catchment is further obtained from the overall water balance in the catchment. For the waterborne tracer transport through the catchment, morphological dispersion is accounted for by topographical analysis of the distribution of pathway lengths to the catchment outlet. Macrodispersion is accounted for heuristically by assuming an effective Peclet number. Distribution of water travel times through the catchment reflect the dispersion on both levels and are derived in both a forward mode (transit time from input to outlet) and a backward mode (water age when arriving at outlet arrival). The forward distribution of water travel times is further used for the tracer discharge modeling by convolution. The approach is applied to modeling of a 23 year long chloride data series for a specific catchment Kringlan (Sweden), and for generic modeling to better understand the dependence of the tracer discharge distribution on different dispersion aspects. The KPA is found to provide reasonable estimates of tracer discharge distribution, and particularly of extreme values, depending on method for determining the pathway length distribution. As a possible alternative analytical model of tracer transport through a catchment, the reservoir approach generally results in large tracer dispersion. This implies that tracer discharge distributions obtained from a mixed reservoir approach and from KPA are only compatible under large dispersion conditions.

  • 38.
    Soltani, Safeyeh Sofie
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Cvetkovic, Vladimir
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Contaminant attenuation by shallow aquifer systems under steady flow2017Ingår i: Advances in Water Resources, ISSN 0309-1708, E-ISSN 1872-9657, Vol. 108, s. 157-169Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We present a framework for analyzing advection-dominated solute transport and transformation in aquifer systems of boreal catchments that are typically shallow and rest on crystalline bedrock. A methodology is presented for estimating tracer discharge based on particle trajectories from recharge to discharge locations and computing their first passage times assuming that the flow pattern is approximately steady-state. Transformation processes can be included by solving one-dimensional reactive transport with randomized water travel time as the independent variable; the distribution of the travel times incorporates morphological dispersion (due to catchment geometry/topography) as well as macro-dispersion (due to heterogeneity of underlying hydraulic properties). The implementation of the framework is illustrated for the well characterized coastal catchment of Forsmark (Sweden). We find that macro-dispersion has a notable effect on attenuation even though the morphological dispersion is significantly larger. Preferential flow on the catchment scale is found to be considerable with only 5% of the Eulerian velocities contributing to transport over the simulation period of 375 years. Natural attenuation is illustrated as a simple (linear decay) transformation process. Simulated natural attenuation can be estimated analytically reasonably well by using basic hydrological and structural information, the latter being the pathway length distribution and average aquifer depth to the bedrock.

  • 39.
    Stigsson, Martin
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik. SKB, Swedish Nuclear Fuel and Waste Management Co.
    Cvetkovic, Vladimir
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur. SKB, Swedish Nuclear Fuel and Waste Management Co.
    Ivars, Diego Mas
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Jord- och bergmekanik. SKB, Swedish Nuclear Fuel and Waste Management Co.
    Selroos, Jan-Olof
    SKB, Swedish Nuclear Fuel and Waste Management Co.
    A method to estimate flow and transport properties of sheared synthetic fractures in crystalline rock with different roughness under varying normal stressManuskript (preprint) (Övrigt vetenskapligt)
    Ladda ner fulltext (pdf)
    fulltext
  • 40.
    Teng, Penghua
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Yang, James
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Modeling and Prototype Testing of Flows over Flip-Bucket Aerators2018Ingår i: Journal of Hydraulic Engineering, ISSN 0733-9429, E-ISSN 1943-7900, Vol. 144, nr 12, artikel-id 04018069Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The paper deals with a unique spillway which incorporates an aerator in each flip bucket with the intention to aerate the flow and avoid subatmospheric air cavities enclosed by the jets. In terms of jet breakup and stability, the physical models and the prototype lead to contradicting conclusions. With sealed aerators, the models exhibit intact air cavities featuring negative air pressure, suggesting the aeration need. Computational fluid dynamics (CFD) is performed to determine the reason for the discrepancy. Both the prototype observations and CFD indicate that the jets break up as a result of air entrainment; the resulting cavity air-pressure drops are insignificantly small. The discrepancy is due to the small model scale, in which the threshold flow velocity for air entrainment is not met and the prerequisite for jet breakup does not exist. To correctly reproduce similar water-air flow phenomena, the model should be large enough to meet the air-entrainment criterion. When questioning a small-scale model with air-cavity formation, CFD simulations should be performed to check the model results and make corrections, if needed.

  • 41.
    Torabi Haghighi, A.
    et al.
    Water, Energy and Environmental Engineering Research Unit, University of Oulu, PO Box 4300, 90014, Finland.
    Ashraf, F. B.
    Water, Energy and Environmental Engineering Research Unit, University of Oulu, PO Box 4300, 90014, Finland.
    Riml, Joakim
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Koskela, J.
    Finnish Environment Institute (SYKE), Latokartanonkaari 11, Helsinki 00790, Finland.
    Kløve, B.
    Water, Energy and Environmental Engineering Research Unit, University of Oulu, PO Box 4300, 90014, Finland.
    Marttila, H.
    Water, Energy and Environmental Engineering Research Unit, University of Oulu, PO Box 4300, 90014, Finland.
    A power market-based operation support model for sub-daily hydropower regulation practices2019Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 255, artikel-id 113905Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    With increasing power production from renewable energy sources, sub-daily variations in energy demand need to be balanced. Today, hydropower is commonly used as balancing power. In this study, we quantified the impact of capacity constraints, in terms of reservoir volume and hydropower capacity, on the potential to comply with instant energy demand. To evaluate the impact, we developed two new metrics, power market impact and system efficiency ratio, which are based on two threshold flow regimes derived from natural flow as lower threshold release and regulated flow (based on hourly energy prices) as upper threshold release. The operation support model comprises 96 different regulation scenarios based on varying combinations of hydropower and reservoir capacities. For each scenario, an hourly water balance was simulated, to obtain the highest complying with upper threshold release based on actual energy demand. We tested the framework on the Kemijoki river with defined thresholds based on the natural flow regime (tributary river Ounasjoki) and the hourly energy price in Finland in 2017, and estimated the impact of regulation on hourly flow regime at the Taivalkoski hydropower station. The annual flow regime impact in 2013, 2014 and 2015 was estimated to be 74%, 84% and 61%, respectively, while the monthly impact varied from 27% to 100%. Our framework for evaluating interactions between the power market and sub-daily regulation practices is a useful novel tool for sustainable river management and can be easily applied to different rivers and regions and evaluated for different timescales.

  • 42.
    Vigouroux, Guillaume
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Destouni, G.
    Stockholm Univ, Dept Phys Geog, S-10691 Stockholm, Sweden..
    Jonsson, A.
    COWI AB, Solna Strandvag 78, S-78 Solna, Sweden..
    Cvetkovic, Vladimir
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur. Royal Inst Technol KTH, Resources Energy & Infrastruct Sustainabil Assess, Teknikringen 10B, S-10044 Stockholm, Sweden..
    A scalable dynamic characterisation approach for water quality management in semi-enclosed seas and archipelagos2019Ingår i: Marine Pollution Bulletin, ISSN 0025-326X, E-ISSN 1879-3363, Vol. 139, s. 311-327Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In semi-enclosed seas, eutrophication may affect both the coastal waters and the whole sea. We develop and test a modelling approach that can account for nutrient loads from land as well as for influences and feedbacks on water quality across the scales of a whole semi-enclosed sea and its coastal zones. We test its applicability in the example cases of the Baltic Sea and one of its local archipelagos, the Archipelago Sea. For the Baltic Sea scale, model validation shows good representation of surface water quality dynamics and a generally moderate model performance for deeper waters. For the Archipelago Sea, management scenario simulations show that successful sea measures may have the most important effects on coastal water quality. This highlights the need to consistently account for whole-sea water-quality dynamics and management effects, in addition to effects of land drivers, in modelling for characterisation and management of local water quality.

  • 43.
    Wang, Jun-Zhi
    et al.
    Yellow River Engn Consulting Co Ltd YREC, Zhengzhou, Henan, Peoples R China..
    Wörman, Anders
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Spectral Analysis of River Resistance and Aquifer Diffusivity in a River-Confined Aquifer System2019Ingår i: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 55, nr 10, s. 8046-8060Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Hydraulic connections between a river and an adjacent aquifer are controlled by the river resistance and aquifer diffusivity. In this paper, we derive a spectral solution linking the power spectrum of river stage fluctuations to that of the hydraulic head of a confined aquifer by means of a physical scaling factor. The physical scaling factor represents an algebraic expression of the river resistance and aquifer diffusivity and is included in an exact spectral solution derived herein. Statistical measures of the aquifer diffusivity and river resistance are provided by fitting the solution versus observed groundwater hydraulic head obtained at several distances and/or frequencies. At a study site in the middle reach of the Yangtze River and downstream of the Three Gorges Dam in China, we find systematic damping of the hydraulic head variations with distance from the river, which follows a fractal pattern driven by the river stage. In general, the estimated parameters are consistent with results reported in the literature, which supports the validity of the proposed spectral approach, although the paper discusses advantages and limitations due to application conditions.

  • 44.
    Wei, Jieqiang
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Reglerteknik.
    Nekouei, Ehsan
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Reglerteknik.
    Wu, J.
    Cvetkovic, Vladimir D.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Johansson, Karl H.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Reglerteknik.
    Steady-state analysis of a human-social behavior model: A neural-cognition perspective2019Ingår i: Proceedings of the American Control Conference, Institute of Electrical and Electronics Engineers (IEEE), 2019, s. 199-204, artikel-id 8814786Konferensbidrag (Refereegranskat)
    Abstract [en]

    We consider an extension of the Rescorla-Wagner model which bridges the gap between conditioning and learning on a neural-cognitive, individual psychological level, and the social population level. In this model, the interaction among individuals is captured by a Markov process. The resulting human-social behavior model is a recurrent iterated function system which behaves differently from the classical Rescorla-Wagner model due to randomness. A sufficient condition for the convergence of the forward process starting with arbitrary initial distribution is provided. Furthermore, the ergodicity properties of the internal states of agents in the proposed model are studied.

  • 45.
    Wei, Jieqiang
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Wu, Junfeng
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Molinari, Marco
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Cvetkovic, Vladimir
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Johansson, Karl Henrik
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    On the modeling of neural cognition for social network applications2017Ingår i: 2017 IEEE Conference on Control Technology and Applications (CCTA), Institute of Electrical and Electronics Engineers (IEEE), 2017Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, we study neural cognition in social network. A stochastic model is introduced and shown to incorporate two well-known models in Pavlovian conditioning and social networks as special case, namely Rescorla-Wagner model and Friedkin-Johnsen model. The interpretation and comparison of these model are discussed. We consider two cases when the disturbance is independent identically distributed for all time and when the distribution of the random variable evolves according to a Markov chain. We show that the systems for both cases are mean square stable and the expectation of the states converges to consensus.

  • 46.
    Wörman, Anders
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Mojarrad, Babak Brian
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Riml, Joakim
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Fragmentation of the Hyporheic Zone Due to Regional Groundwater Circulation2019Ingår i: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 55, nr 2, s. 1-21Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    By use of numerical modeling and field observations, this work quantified the effects of catchment-scale upwelling groundwater on the hyporheic (below stream) fluxes over a wide range of spatial scales. A groundwater flow model was developed that specifically accounted for the hydrostatic and dynamic head fluctuations induced by the streambed topography. Although the magnitudes and relative importance of these streambed-induced fluxes were found to be highly sensitive to site-specific hydromorphological properties, we showed that streambed topographic structures exert a predominant control on the magnitude of hyporheic exchange fluxes in a Swedish boreal catchment. The magnitude of the exchange intensity evaluated at the streambed interface was found to be dominated by the streambed-induced hydraulic head across stream order. However, the catchment-scale groundwater flow field substantially affected the distribution of groundwater discharge points and thus decreased the fragmentation of the hyporheic zone, specifically by shifting the cumulative density function toward larger areas of coherent upwelling at the streambed interface. This work highlights the spectrum of spatial scales affecting the surface water-groundwater exchange patterns and resolves the roles of key mechanisms in controlling the fragmentation of the hyporheic zone.

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  • 47. Xie, Q.
    et al.
    Yang, James
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Lundström, S.
    Dai, W.
    Understanding morphodynamic changes of a tidal river confluence through field measurements and numerical modeling2018Ingår i: Water, ISSN 2073-4441, E-ISSN 2073-4441, Vol. 10, nr 10, artikel-id 1424Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A confluence is a natural component in river and channel networks. This study deals, through field and numerical studies, with alluvial behaviors of a confluence affected by both river run-offand strong tides. Field measurements were conducted along the rivers including the confluence. Field data show that the changes in flow velocity and sediment concentration are not always in phase with each other. The concentration shows a general trend of decrease from the river mouth to the confluence. For a given location, the tides affect both the sediment concentration and transport. A two-dimensional hydrodynamic model of suspended load was set up to illustrate the combined effects of run-offand tidal flows. Modeled cases included the flood and ebb tides in a wet season. Typical features examined included tidal flow fields, bed shear stress, and scour evolution in the confluence. The confluence migration pattern of scour is dependent on the interaction between the river currents and tidal flows. The flood tides are attributable to the suspended load deposition in the confluence, while the ebb tides in combination with run-offs lead to erosion. The flood tides play a dominant role in the morphodynamic changes of the confluence.

  • 48.
    Xie, Qiancheng
    et al.
    Lulea Univ Technol, Div Fluid & Expt Mech, S-97187 Lulea, Sweden..
    Yang, James
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Lundström, T. Staffan
    Lulea Univ Technol, Div Fluid & Expt Mech, S-97187 Lulea, Sweden..
    Field Studies and 3D Modelling of Morphodynamics in a Meandering River Reach Dominated by Tides and Suspended Load2019Ingår i: FLUIDS, ISSN 2311-5521, Vol. 4, nr 1, artikel-id 15Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Meandering is a common feature in natural alluvial streams. This study deals with alluvial behaviors of a meander reach subjected to both fresh-water flow and strong tides from the coast. Field measurements are carried out to obtain flow and sediment data. Approximately 95% of the sediment in the river is suspended load of silt and clay. The results indicate that, due to the tidal currents, the flow velocity and sediment concentration are always out of phase with each other. The cross-sectional asymmetry and bi-directional flow result in higher sediment concentration along inner banks than along outer banks of the main stream. For a given location, the near-bed concentration is 2-5 times the surface value. Based on Froude number, a sediment carrying capacity formula is derived for the flood and ebb tides. The tidal flow stirs the sediment and modifies its concentration and transport. A 3D hydrodynamic model of flow and suspended sediment transport is established to compute the flow patterns and morphology changes. Cross-sectional currents, bed shear stress and erosion-deposition patterns are discussed. The flow in cross-section exhibits significant stratification and even an opposite flow direction during the tidal rise and fall; the vertical velocity profile deviates from the logarithmic distribution. During the flow reversal between flood and ebb tides, sediment deposits, which is affected by slack-water durations. The bed deformation is dependent on the meander asymmetry and the interaction between the fresh water flow and tides. The flood tides are attributable to the deposition, while the ebb tides, together with run-offs, lead to slight erosion. The flood tides play a key role in the morphodynamic changes of the meander reach.

  • 49.
    Yang, James
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur. Vattenfall AB Res & Dev, Alvkarleby Lab, SE-81426 Alvkarleby, Sweden.
    Andreasson, Patrik
    Vattenfall AB Res & Dev, Alvkarleby Lab, SE-81426 Alvkarleby, Sweden.;Lulea Univ Technol, Div Fluid & Expt Mech, SE-97187 Lulea, Sweden..
    Högström, Carl-Maikel
    Vattenfall AB Res & Dev, Alvkarleby Lab, SE-81426 Alvkarleby, Sweden..
    Teng, Penghua
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    The Tale of an Intake Vortex and Its Mitigation Countermeasure: A Case Study from Akkats Hydropower Station2018Ingår i: Water, ISSN 2073-4441, E-ISSN 2073-4441, Vol. 10, nr 7, artikel-id 881Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The upgrade of Akkats power station in Sweden included a new, separate waterway for the addition of a 75 MW generating unit. The vertical intake of its headrace was formed by means of lake tapping. A physical model was used to help understand the blasting process involving fragmented rock, water, air, and gas. Upon commissioning of the unit, swirling flows occurred unexpectedly at the intake, which gave rise to negative consequences including limitations in power output. Echo-sounding showed that the blasted piercing resulted in an irregular intake. A hydraulic model, as part of the design process, was built to examine potential countermeasures for vortex suppression. The final solution was a segmented barrier between the intake and the dam. It effectively suppressed the intake flow circulations; only minor intermittent vortices were left. The fabricated steel segments were anchored into the bedrock, stretching to 1.0 m below the lowest legal reservoir level. The local intake headloss was also reduced. The implemented solution was tested under full turbine loading and the result was satisfactory. Even during winter seasons with ice cover above the wall, the power station ran normally. The case study is expected to provide guidance for solving similar problems with vortex formation.

  • 50.
    Yang, James
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Andreasson, Patrik
    Teng, Penghua
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Resurser, energi och infrastruktur.
    Xie, Qiancheng
    The Past and Present of Discharge Capacity Modeling for Spillways-A Swedish Perspective2019Ingår i: FLUIDS, ISSN 2311-5521, Vol. 4, nr 1, artikel-id 10Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Most of the hydropower dams in Sweden were built before 1980. The present dam-safety guidelines have resulted in higher design floods than their spillway discharge capacity and the need for structural upgrades. This has led to renewed laboratory model tests. For some dams, even computational fluid dynamics (CFD) simulations are performed. This provides the possibility to compare the spillway discharge data between the model tests performed a few decades apart. The paper presents the hydropower development, the needs for the ongoing dam rehabilitations and the history of physical hydraulic modeling in Sweden. More than 20 spillways, both surface and bottom types, are analyzed to evaluate their discharge modeling accuracy. The past and present model tests are compared with each other and with the CFD results if available. Discrepancies do exist in the discharges between the model tests made a few decades apart. The differences fall within the range -8.3%-+11.2%. The reasons for the discrepancies are sought from several aspects. The primary source of the errors is seemingly the model construction quality and flow measurement method. The machine milling technique and 3D printing reduce the source of construction errors and improve the model quality. Results of the CFD simulations differ, at the maximum, by 3.8% from the physical tests. They are conducted without knowledge of the physical model results in advance. Following the best practice guidelines, CFD should generate results of decent accuracy for discharge prediction.

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