Luleå University of Technology Publications
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Toxicological effects of building surface runoff on three aquatic species from different trophic levels
No full textExterior building materials contribute to stormwater runoff pollution but knowledge of how ecological impacts may vary between different types of building materials remains limited. This study combined chemical analyses of runoff from seven different building surface materials with toxicological response analyses as a contribution to addressing this knowledge gap. Results indicate a range of inorganic (e.g. copper, zinc) and organic substances (e.g. diisononyl phthalate, DINP, and nonylphenol) are mobilised by runoff, with concentrations varying between differing materials and rain events by up to three orders of magnitude. Toxicological analysis involving algae, daphnids and fish embryos, indicated that acute and chronic effects also varied between building materials and events, as well as species. For example, copper sheet runoff (maximum concentration 2900 µg/L) exhibited the strongest acute toxic effect on all three test organisms (≥80 % effect irrespective of event and species). Chronic reproductive effects were reported for Daphnia magna on exposure to PVC and bitumen felt roof runoff. Results show that runoff from several building surface materials commonly found in urban areas can cause acute and chronic effects on aquatic organisms. Findings could support users to identify environmentally sustainable building materials as a contribution to reducing pollution emissions from cities to receiving waters.Full text: CC BY license;</p
Development and systematic evaluation of aqueous triazole chloride-based deep eutectic solvents for efficient CO2 capture
No full textDeep eutectic solvents (DESs) have attracted considerable attention as promising alternatives to conventional solvents for mitigating CO2 emissions due to their tunable structures, low volatility, and promising physicochemical properties. In this work, a series of [Triz]Cl/amine DESs were designed and synthesized and then formulated as 30 wt% aqueous solutions (30 wt% DES + 70 wt% H2O) to systematically investigate how the type of hydrogen bond donor (HBD) affects their physicochemical properties, thermal stability, and CO2 capture performance, and to identify the most effective solvent; their CO2 absorption capacity, absorption rate, thermal stability, and desorption efficiency were determined experimentally, and a novel stepwise evaluation strategy was employed for identification. [Triz]Cl/DETA was identified, exhibiting significantly enhanced performance, with CO2 absorption capacity, absorption rate, thermal stability, and cyclic loading increased by 34%, 12%, 114%, and 39%, respectively, when compared with the conventional monoethanolamine (MEA). Its viscosity (both before and after CO2 absorption), oxidative stability, and corrosion resistance were further studied, confirming the superior performance, and the reaction mechanism was also elucidated. This work provides valuable insights into the structure–property relationships of DESs and establishes [Triz]Cl/DETA-based solvents as promising candidates for efficient and sustainable CO2 capture applications.Funder: Europeiska Unionen; National Key Researchand Development Program of China (2024YFE0206200)Full text license: CC BY</p
The role of ore and host rock mineralogy in the beneficiation of a VMS deposit: insights from Rävliden North, northern Sweden
No full textThe grinding and flotation performance of Zn-Pb-Cu-Ag ores is highly sensitive to ore mineralogy, host rock composition, and textural variability, factors that are often overlooked in favour of bulk grade values. This study examines the Rävliden North Zn-Cu-Pb-Ag volcanogenic massive sulphide deposit (VMS) deposit in northern Sweden. Two main ore types are identified: massive sphalerite- and galena-rich ore and chalcopyrite-rich vein-dominated ore that coupled with host rock type led to further 6 sub-types. Mineralogical and textural characterisation of flotation feed and products, using Quantitative Evaluation of Minerals by Scanning Electron Microscopy (QEMSCAN®) and element to mineral conversion (EMC) based on multi-element chemical assays, reveals that fine-grained, sphalerite-dominated ore is more amenable to grinding and exhibit better liberation, enhancing flotation efficiency. In contrast, chalcopyrite-rich ore perform better in Cu-Pb flotation but is harder to grind due to its silicate-rich gangue (e.g., quartz). Minerals such as micas, amphiboles, and carbonates affect ore hardness, and ore mineralogy (sphalerite, galena, chalcopyrite and Ag mineralogy) directly affects flotation efficiency. Blending of poor grade and hard to grind (problematic) ores with better grade and softer to grind (fairly good to good) ore is recommended to improve concentrate quality. Precious, critical, and deleterious elements are mostly recovered in the chalcopyrite-galena flotation circuit in amalgams (Ag, Hg), dyscrasite (Ag, Sb), hessite (Ag), sulphosalts (Ag, Sb, Bi), native Bi, and tellurobismuthite (Bi). These minerals are fine-grained (< 20 µm) and poorly liberated, leading to recovery in both target and non-target flotation concentrates. Nevertheless, established metallurgical methods enable their efficient extraction maximising ore value. This study highlights the importance of process mineralogy for improved beneficiation in concentration circuits, and the understanding of by-products during processing of complex polymetallic ores.Full text license: CC BY 4.0;Funder: Boliden </p
Stormwater hydraulic modeling : A comparative study of MIKE+ & InfoDrainage
No full textEffective stormwater management is important in urban environments to mitigate flooding, manage peak flows, and support resilient infrastructure planning. Hydraulic modeling tools play a critical role in the design and analysis of drainage networks, yet different software tools often rely on different assumptions, numerical methods, and model structures which raise questions about comparability and reliability. This study compares two widely used stormwater modeling tools, MIKE+ and InfoDrainage. Identical drainage systems were simulated under identical input conditions, including synthetic rainfall events, Chicago Design Storms and block rain with 10- and 30-year return periods. Results show that despite identical inputs, the two models produced notable differences in peak flow rates, timing of runoff, surcharging behavior, and flood extents, particularly under high-intensity rainfall events. These differences are largely attributed to differences in numerical solvers, surcharge handling and handling of node interactions. While MIKE+ typically produced higher peaks, InfoDrainage exhibited more numerical instability in the hydrographs and fewer instances of surcharging. The study also highlights the implications of uncertainty in model structure and solver design, especially in the absence of field calibration. The findings demonstrate that MIKE+ and InfoDrainage are not functionally interchangeable, and model results must be interpreted in the context of each software’s assumptions. This comparison contributes to a more informed selection of modeling tools in stormwater design and planning and emphasizes the need for calibration, sensitivity analysis, and model transparency in future applications.Effektiv hantering av dagvatten är avgörande i urbana miljöer för att minska översvämningsrisker, hantera flödestoppar och stödja hållbar infrastrukturplanering. Hydrauliska modelleringsverktyg spelar en central roll vid dimensionering och analys av dagvattensystem, men olika programvaror bygger ofta på skilda antaganden, numeriska metoder och modellstrukturer, vilket väcker frågor om jämförbarhet och tillförlitlighet. I denna studie jämförs två vanligt förekommande modelleringsverktyg, MIKE+ och InfoDrainage, genom att simulera identiska dagvattensystem med harmoniserade indata, inklusive syntetiska regn (10- och 30-årsregn enligt Chicago Design Storm och blockregn). Resultaten visar att modellerna trots identiska indata genereras märkbara skillnader i flödestoppar, tidpunkt för avrinning, överbelastningar och översvämning, särskilt vid mer intensiva regn. Dessa skillnader kan i huvudsak förklaras av olikheter i numeriska lösningsmetoder, hanteringen av överbelastade rör och hanteringen av brunnar. MIKE+ tenderar att ge högre flödestoppar, medan InfoDrainage genererade flödeskurvor med mer svängningar och färre överbelastningar. Studien belyser även betydelsen av modellstrukturell osäkerhet, särskilt när kalibrering mot uppmätta data saknas. Slutsatsen är att MIKE+ och InfoDrainage inte är direkt utbytbara, och att resultaten bör tolkas med hänsyn till respektive programvaras bakomliggande antaganden. Denna jämförelse bidrar till en mer informerad modellvalprocess vid dagvattenplanering och betonar behovet av kalibrering, känslighetsanalyser och ökad transparens i framtida tillämpningar
Vassbäddars potential vid rening av avloppsvatten med fokus på mikroföroreningar : Rening och förekomst av läkemedel och PFAS
No full textFunder: LOVA (Länsstyrelsen); Luleå miljöresurs AB;</p
Mindfulness as an intervention for chronic low back pain : A literature review
No full textBakgrund: Kronisk ländryggssmärta är ett vanligt problem hos den vuxna befolkningen. Smärtan påverkar både livskvalitet och funktion. Mindfulness-baserade interventioner är en behandlingsmetod som används inom fysioterapin och har visat sig kunna påverka smärta, stress och psykologiska faktorer. Trots den tilltagande användningen saknas sammanställd litteratur om mindfulness som behandlingsmetod vid kronisk ländryggssmärta. Syfte: Denna litteraturstudie syftar till att belysa hur mindfulnessbaserade interventioner påverkar smärtupplevelsen hos personer med kronisk ländryggssmärta. Metod: En systematisk litteratursammanställning genomfördes genom sökningar i databaserna PubMed och CINAHL. Nio RCT-studier inkluderades för att svara på syftet. Resultat: Mindfulness-baserade interventioner visade enligt majoriteten av studierna ha en påverkan på smärtupplevelsen. En minskning på smärtintensitet, smärtbesvär och smärtacceptans jämfört med sedvanlig vård. Flera av studierna rapporterade också bättre hantering av katastroftankar. Mindfulness effekter på smärtupplevelsen var likvärdiga med kognitiv beteendeterapi (KBT). Konklusion: Mindfulness kan ge positiva förändringar på smärtupplevelsen hos personer med kronisk ländryggssmärta. Behandlingsmetoden kan ses som en relevant komponent i behandlingen av kronisk ländryggssmärta
Acidogenic valorization of agricultural residues and industrial waste streams: substrate composition regulating the microbial community and metabolites
No full textThe global waste crisis is a significant concern driven by urbanization and economic expansion. Untreated waste poses major environmental, economic, and societal challenges, especially affecting agriculture and industry. Addressing this crisis necessitates innovative waste management strategies and sustainable practices to mitigate the impending waste burden on ecosystems and societies worldwide. Recent advancements in biofuels and biochemicals intensified research into the conversion of biogenic waste into bio-carboxylic acid/volatile fatty acids (VFAs), driven by the dual imperatives of sustainable waste management and renewable resource development. This study presents a comparative analysis of three waste streams: cheese whey from the cheese-making industry, lignocellulosic brewery spent grains (BSG), and agricultural by-products like wheat straw (WS) assessing their efficacy in carboxylic acid production by mixed culture fermentation. Each substrate produced a diverse array of carboxylic acids, including acetic, propionic, butyric, valeric, iso-valeric, and caproic acids exhibiting unique fermentation efficiencies in carboxylic acid production. The experimental results reveal distinct fermentation efficiencies, the highest concentration of short-chain carboxylic acids (SCCA) production of 11.84 gCOD per L from CW, alongside a medium-chain carboxylic acid (MCCA) production of 3.95 gCOD per L. Notably, despite the lignocellulosic composition of the substrates, both BSG and WS demonstrated substantial and competitive yields of SCCA and MCCA. Specifically, BSG produced 10.68 gCOD per L of SCCA and 3.54 gCOD per L of MCCA, while WS yielded 11.51 gCOD per L of SCCA and 3.84 gCOD per L of MCCA. These findings highlight the viability of lignocellulosic substrates for carboxylic acid production, suggesting significant opportunities for enhancing bioprocessing strategies in biochemical and industrial applications. Taxonomic analysis of microbial communities showed a significant predominance of Firmicutes, Bacteroidota, and Actinobacteriota. The Clostridiaceae family exhibited dominance across all reactors, with respective abundances of 82.72%, 27.67%, and 61.29%. The BSG uniquely showcased an enrichment of Lactobacillaceae (23.86%), Ruminococcaceae (7.72%), and Prevotellaceae (3.24%). Key genera contributing to carboxylic acid production included Clostridium sensu stricto 1, Romboutsia, and Enterococcus. This diversity highlights the influence of substrate composition on microbial community structure, highlighting the intricate relationships between substrate nature and microbial metabolites suggesting that strategic substrate selection could optimize fermentation efficiency and enhance product yield.Full text license: CC BY 3.0;</p
Plasmasmältning och centrifugalatomisering av eldfasta legeringar och föreningar
No full textThe development of fabrication technologies suitable for the production of fine, high-quality metallic powders of conventional and novel alloys is crucial to the development of the powder metallurgy route. The plasma-assisted centrifugal atomization process was developed by Metasphere Technology AB for the production of spherical cast tungsten carbide, and subsequently acquired by Höganäs AB. In the standard implementation of the process, feedstock material in the form of crushed powder is fed into a rotating crucible, melted by a transferred plasma arc, and atomized in the form of fine, spherical droplets. The capability to melt alloys and compounds with melting temperatures above 3,000 ᵒC, combined with the extremely rapid solidification of the ejected droplets, allows for the processing of metastable refractory alloys that cannot be obtained otherwise. The main objectives of this work were to (1) better understand the role of the centrifugal atomization mechanism on the microstructure and the mechanical properties of the final powders, and (2) explore the capabilities of a pilot-scale plasma-assisted centrifugal atomization unit for the design and development of novel refractory alloys. The local mechanical characterization of micron-sized powders of hard and brittle compounds is challenging. The use of three-dimensional topography images to measure the residual imprints of microindentation hardness tests has been proposed, ultimately enabling a reliable comparison among CTC powders fabricated by different methods. The microindentation hardness, the micro-pillar compressive strength, and the resistance to cyclic compressive loading of entire particles were extensively investigated in centrifugally-atomized CTC powders subjected to different heat treatments. Suitable processing routes for the fabrication of spherical powders of a compositionally complex Ti-V-Zr-Nb-Mo-Hf-Ta-W refractory high-entropy alloy have been developed. The preparation of pre-alloyed feedstock material by partial sintering followed by cryogenic crushing was considered. Subsequently, the simultaneous melting, alloying, and atomization of a blend of elemental powders was envisaged as an alternative to the time-consuming cryogenic crushing. The microstructure, the indentation hardness, the phase stability, the prospects of consolidation into bulk alloys, and the hydrogenation behavior of the alloys thus produced have been extensively investigated
Analysis of Production Area Layouts in Sublevel Caving Mines Using Discrete Event Simulation
No full textA traditional production layout is typically adopted in sublevel caving mines. However, as mining operations progress to deeper levels, increasing stresses necessitate exploring alternatives for production layouts. Other aspects of traditional production layouts that need to be improved are productivity, development distance, safety, and automation. Possible alternatives to the traditional layout are the fork and the heart layouts which might potentially be used in production areas. To evaluate and compare the production capacity of these layouts, this study analyzed the productivity and energy consumption of Load-Haul-Dump (LHD)vehicles using discrete event simulation (DES) method. Productivity of diesel-powered LHDs was analyzed in the traditional, the fork, and the heart layouts; productivity and energy consumption of battery-powered LHDs were analyzed in the traditional and the fork layouts. Findings showed productivity was 9-10% and 38% higher in the traditional layout than in the fork and the heart layouts, respectively, when diesel-powered LHD operations were simulated. Energy consumption per tonne of battery-powered LHDs was 10-11% lower in the traditional layout than in the fork layout, and the productivity of battery-powered LHDs was 9% higher in the traditional layout than the fork layout. Although the production capacities of these alternative layouts are lower than the capacity of the traditional layout, alternative layouts can be preferred if the perimeter drive or ore passes are positioned farther away from the production drifts to mitigate instability in the structures near the orebody boundary. When designing a production area layout, several aspects need to be considered in addition to productivity to balance the potential trade-offs between productivity and other factors such as safety and stability
Behind the Scenes of Pro-Environmental Tourist Behavior : Exploring Barriers, Drivers, and Antecedents
No full textThis mixed-method dissertation explores the barriers, drivers, and antecedents of pro-environmental behavior in tourism, with a focus on Generations Y and Z. Based on interviews with Generation Z consumers, the first study identifies primarily low motivation, but also limited knowledge, and restricted opportunities as key barriers to pro-environmental travel engagement. It proposes structural and informational interventions to make eco-friendly options more appealing and accessible. The second study delves into Reddit discussions, uncovering that while users recognize the link between tourism and climate change, low self-efficacy and ten perceived barriers hinder important behaviors. The findings provide insights into which tourism choices are important for consumers when striving to minimize their climate impact. The third study draws on survey data to compare Generations Y and Z on psychological constructs influencing their pro-environmental behavior. The results show that Generation Y reports higher levels of psychological empowerment and perceived social norms. Perceived behavioral control is identified as the strongest predictor of personal norms, followed by psychological empowerment and awareness of consequences. The study also reveals a striking gap: while 65% of respondents report strong personal norms to protect the environment, less than 3% of the total sample chose to learn more about eco-friendly travel when given the opportunity in the online setting. The fourth study, also survey-based, examines how subjective knowledge, awareness of consequences, environmental concern, and psychological empowerment influence personal norms and behavioral intentions. A moderation analysis finds that environmental concern has a stronger impact among individuals with higher objective environmental knowledge. The dissertation presents key lessons learned during the PhD journey, offering a discussion of strengths, areas for improvement, and integrated insights from all studies.Denna avhandling som är baserad på en blandad metodansats undersöker barriärer, drivkrafter, och faktorer som påverkar miljövänligt beteende inom turism med fokus på Generation Y och Z. Den första studien, som bygger på intervjuer med konsumenter från Generation Z, identifierar framför allt låg motivation, men även begränsad kunskap och begränsade möjligheter som centrala hinder för engagemang i miljövänligt resande. Studien föreslår strukturella och informativa åtgärder för att göra miljövänliga alternativ mer tilltalande och tillgängliga. Den andra studien undersöker diskussioner på Reddit och avslöjar att även om användare inser kopplingen mellan turism och klimatförändringar, hindras viktiga beteenden av låg självförmåga och tio upplevda barriärer. Resultaten ger insikter om vilka val inom turism som är viktiga för konsumenter som strävar efter att minimera sin klimatpåverkan. Den tredje studien bygger på enkätdata och jämför Generation Y och Z utifrån psykologiska faktorer som påverkar miljövänligt beteende. Resultaten visar att Generation Y rapporterar högre nivåer av psykologisk egenmakt och upplevda sociala normer. Upplevd beteendekontroll identifieras ha störst påverkan på personliga normer, följt av psykologisk egenmakt och medvetenhet om konsekvenser. Studien visar också ett signifikant gap: medan 65% av respondenterna rapporterar starka personliga normer för att skydda miljön, valde mindre än 3% av det totala urvalet att lära sig mer om miljövänligt resande när de fick möjlighet i den digitala miljön. Den fjärde studien, som också bygger på enkätdata, undersöker hur subjektiv kunskap, medvetenhet om konsekvenser, miljöoro och psykologisk egenmakt påverkar personliga normer och beteendeintentioner. En moderationsanalys visar att miljöoro har större effekt bland individer med hög objektiv miljökunskap. Avhandlingen presenterar centrala lärdomar från doktorandresan och innehåller en diskussion om styrkor, förbättringsområden och integrerade insikter från samtliga studier.