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  • Sandberg, Karin
    et al.
    RISE - Research Institutes of Sweden, Byggteknik.
    Pousette, Anna
    RISE - Research Institutes of Sweden, Byggteknik.
    Norén, Joakim
    RISE - Research Institutes of Sweden, Byggteknik.
    Sandberg, Marcus
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Olofsson, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Mukkavaara, Jani
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Hållbarhetsutvärdering av byggnader: Case Ripan i Kiruna2018Report (Other academic)
    Abstract [en]

    Sustainability includes several parameters, and these can be measured and valued in many different ways. This study focuses on balancing the various parts to achieve sustainability by minimizing energy for heating and energy to produce the materials used in the building as well as minimizing cost for material investment and cost for heating using optimization techniques. This is balanced together with the environmental impact. This report describes an initial study for sustainability optimization of a smaller building. The goal is to develop a comprehensive approach to provide a broader basis of decisions for new construction.

    The calculation included the building envelope (exterior walls, roof and floors), interior walls and stabilizing elements for different frames of wood (timber frame and CLT).

    The result from the Ripan Case shows that the timber frame design has the lowest embodied energy and operating energy, and lowest cost for investment and heating during the operating phase. The environmental impact of the timber frame design was also low.

  • Schillings, Audrey
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Swedish Institute of Space Physics (IRF), Kiruna, Sweden .
    Slapak, Rikard
    EISCAT Scientific Association, Kiruna.
    Nilsson, Hans
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Swedish Institute of Space Physics (IRF), Kiruna.
    Yamauchi, Masatoshi
    Swedish Institute of Space Physics (IRF), Kiruna.
    Dandouras, Iannis
    Université de Toulouse, CNRS, UPS, CNES, Toulouse, France.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Earth atmospheric loss through the plasma mantle and its dependence onsolar wind parameters2019Conference paper (Refereed)
  • Chipp, Kerry
    et al.
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Business Administration and Industrial Engineering. University of Pretoria, Johannesburg, South Africa.
    Wocke, Albert
    University of Pretoria, Johannesburg, South Africa.
    Strandberg, Carola
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Business Administration and Industrial Engineering.
    Chiba, Manoj
    University of Pretoria, Johannesburg, South Africa.
    Overcoming African institutional voids: Market entry with networks2019In: European Business Review, ISSN 0955-534X, E-ISSN 1758-7107Article in journal (Refereed)
    Abstract [en]

    Purpose

    Literature on modes of entry has focussed on firm-level strategies. The predominant theories used are Institutional Theory and the resource based view. Using an alternate approach, network theory, the paper demonstrates an additional mode of entry: multiple firms entering together as an extension of an existing loose network, known as a bridging network. The extension of an external network across borders is an appropriate mode of entry in emerging markets with no pre-existing networks or existing networks within a market that are weak, immature or missing.

    Design/methodology/approach

    A conceptual review, which develops four propositions, demonstrating that market entry with bridging networks may be the preferred mode of entry in the presence of institutional voids. Alternative modes may not be viable due to costs and risks associated with overcoming such voids

    Findings

    Existing theory and case examples supports the contention that market conditions facilitate firms to enter as networks rather than as singular entities. These conditions are found in markets with institutional voids and explain the dominant form of business groups in many countries and the operation of loose strategic alliances in emerging markets. Network entry facilitates market access speed may allow for local ties to remain undeveloped or be a first step in building in-country networks.

    Originality/value

    This paper heeds to the call for a network ecosystem approach to market entry, arguing that firms may enter as a collective in subsistence and emerging markets which would explain the preponderance of business groups and loose alliances found.

  • Segerstedt, Eugenia
    et al.
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Human and technology.
    Abrahamsson, Lena
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Human and technology.
    Diversity of livelihoods and social sustainability in established mining communities2019In: The Extractive Industries and Society, ISSN 2214-790X, E-ISSN 2214-7918Article in journal (Refereed)
    Abstract [en]

    The challenges for any community that seeks to maintain a healthy and thriving social life around an operating mine have been considered at some length in research, but the picture is still far from complete. In order to pinpoint some of the gaps in research, the literature on social sustainability as applied to established mining communities in developed countries is here reviewed, and the general understanding of the social sustainability of such communities is touched on. Diversity of livelihoods is explored as an analytical lens which can be used to approach social sustainability challenges without essentializing the preferences of social groups. Extensive literature searches with keywords such as mining, work, gender, organization, social, sustainability, community, town, area, cohesion and inclusion were conducted. The results of our review show a research gap between studies of mining companies and studies of wider mining communities. We conclude that considering diversity of livelihoods can be a productive analytical tool when approaching aspects of social sustainability such as social cohesion and inclusion, gender equality, managed migration, demographics, and housing infrastructure. Continued research is recommended to further bridge the gap between studies of mining companies and studies of mining communities from the perspective of social sustainability.

  • André, Andersson
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Utredning av potentiella prosumenter anslutna till Härnösands fjärrvärmenät2019Independent thesis Basic level (professional degree), 180 HE creditsStudent thesis
  • Chronéer, Diana
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Digital Services and Systems.
    Ståhlbröst, Anna
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Digital Services and Systems.
    Habibipour, Abdolrasoul
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Digital Services and Systems.
    Urban Living Labs: Towards an Integrated Understanding of Their Key Components2019In: Technology Innovation Management Review, ISSN 1927-0321, E-ISSN 1927-0321, Vol. 9, no 3, p. 50-62Article in journal (Refereed)
    Abstract [en]

    In today’s ongoing urbanization and escalating climate change, there is an increasing demand on cities to be innovative and inclusive to handle these emerging issues. As an answer to these challenges, and in order to generate and adopt sustainable innovations and nature-based solutions in the urban areas, the concept of urban living labs has emerged. However, to date, there is confusion concerning the concept of the urban living lab and its key components. Some interpret the urban living lab as an approach, others as a single project, and some as a specific place – and some just do not know. In order to unravel this complexity and better understand this concept, we sought to identify the key components of an urban living lab by discussing the perspective of city representatives in the context of an urban living lab project. To achieve this goal, we reviewed previous literature on this topic and carried out two workshops with city representatives, followed by an open-ended questionnaire. In this article, we identify and discuss seven key components of an urban living lab: governance and management structure; financing models; urban context; nature-based solutions; partners and users (including citizens); approach; and ICT and infrastructure. We also offer an empirically derived definition of the urban living lab concept.

  • Brännström, Emma
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Swidnicki Berg, Sebastian
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Flödessimulering och utveckling av en monteringsstation med avseende på ergonomi, flöde och kvalitet2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This report constitutes the result of a master thesis that was composed at Presetting- and Sharpening at Scanias engine department in Södertälje. The department works as a service organisation for the production lines and its purpose is to maintain the right quality on tools within machining.

    This is done by resharpening of drills and by turning and changing inserts on milling tools. The tools are then adjusted according to given tolerances to obtain correct quality on processed parts. The master thesis project consists of two main parts; analysis of flow and waste within the department with the goal to make the processes more efficient. The other part treats development of an assembly station for milling tools with the aim to improve the ergonomy. The mutual connection for the master thesis project lies within the ergonomy which has been a problem on the assembly station. The demands for the station has been developed mutually to ensure good ergonomy, flow and quality on the work performed on the station. In addition to this, a digitizing has been made of the department to illustrate the proposed changes.

    Through observations, interviews and simulation of flow, wastes and bottlenecks have been detected. For the development of the assembly station the product development process Ulrich and Eppinger has been used.

    The work resulted in a recommendation to institute routines and standardized work methods for how the work is supposed to be performed by operators. A routine should also be instituted on the milling handling station that means that the automatic measurement station always is prioritized by operators to guarantee maximum productivity. Finally, the wash process should be prioritized as a critical part in the daily work and thereby receive machine ownership, and thus make sure that knowledge about the wash process is obtained. The development of the assembly station led to three level based solutions that were supposed to be implemented today, within 1-2 years and a vision about the future's possible assembly station.

  • Elias, Ziyad
    et al.
    Geomorphic Researcher Hannover Germany.
    Sissakian, Varoujan K.
    University of Kurdistan Hewler Iraq. Private Consultant Geologist Erbīl Iraq.
    Al-Ansari, Nadhir
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Assessment of the Tectonic Activity in Northwestern part of the Zagros Mountains, Northeastern Iraq by using Geomorphic Indices2019In: Geotechnical and Geological Engineering, ISSN 0960-3182, E-ISSN 1573-1529Article in journal (Refereed)
    Abstract [en]

    The Tectonic Activity of regions with active tectonics can be assessed by using of the geomorphic indices. Six Geomorphic indices including stream-gradient index (SL), drainage basin asymmetry (Af), drainage basin shape (Bs), hypsometric integral (Hi), valley floor width-valley height ratio (Vf), and mountain-front sinuosity (Smf) were calculated using GIS technique in Kifri Chai Basin; northeast Iraq, which belongs to the Western Zagros Mountain. The basin was divided into eighteen sub-basins depending on the 4th, 5th and 6th stream orders of the drainage within Kirfi Basin. It was found that the SL, Af, Bs, Hi, Vf, and Smf (J) values are uniform and exhibit almost the same classes. However, few exceptions occur, especially in Bs values, but the exceptional values do not influence significantly on the acquired results, in each of the eighteen sub-basin. From these indices the relative active tectonics index value (Iat) was determined. The results of average Iat values (2.35) showed that the tectonic activity in the whole basin is Moderate. Moreover, an attempt was carried out to compare the regional Neotectonic activity with the relative tectonic activity in the basin. The results showed that there is a positive relation between the two comparatives; especially the subsidence amount and scored relative tectonic activity.

  • Chabuk, Ali
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering. Department of Environment Engineering, college of Engineering, U niversity of Babylon, Babylon, Iraq. .
    Al-Ansari, Nadhir
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Hussain, Hussain M.
    Remote Sensing Center, University of Kufa, Kufa, Iraq.
    Laue, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Hazim, Anwer
    Koya university, Koya, Iraq.
    Knutsson, Sven
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Pusch, Roland
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Landfill Sites Selection Using MCDM and Comparing Method of ChangeDetection for Babylon Governorate, Iraq2019In: Environmental science and pollution research international, ISSN 0944-1344, E-ISSN 1614-7499Article in journal (Refereed)
    Abstract [en]

    Landfill site`s selection represents a complicated process due to the large number of variables to be adopted. In this study, an arid area (Babylon Governorate as a case study) was selected. It is located in the middle region of Iraq. In this area, the  landfills do not satisfy the required  international criteria.  Fifteen  of the  most significant criterion were selected for this purpose. For suitable weight for each criterion, the multi criteria decision making (MCDM) methods were applied. These methods are AHP and RSW. In the GIS software 10.5, the raster maps of the chosen criterion were arranged and analysed. The method of change detection was implemented to determine the matching pixels and non-matching pixels. The final results showed that there are two candidate locations for landfills for each district in the governorate (ten sites). The areas of the selected sites were sufficient to contain the cumulative quantity of solid waste from 2020 until 2030.

  • Public defence: 2019-05-10 13:00 F1031, Luleå
    Sayahi, Faez
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Plastic Shrinkage Cracking In Concrete: Mitigation and Modelling2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Early-age (up to 24 hours after casting) cracking may become problematic in any concrete structure. It can have a negative influence on the aesthetics of the concrete structure, as well as decreasing the durability and serviceability by facilitating the ingress of harmful materials into the concrete bulk. Moreover, these cracks may expand gradually during the member’s service-life due to long-term shrinkage and/or loading. Early-age cracking is caused by two driving forces: 1) plastic shrinkage cracking which is a physical phenomenon and occurs due to rapid and excessive loss of moisture, mainly in form of evaporation, 2) chemical reactions between cement and water which causes autogenous shrinkage. In this PhD project only the former is investigated.

    Rapid evaporation from the surface of fresh concrete causes negative pressure, known as capillary pressure, in the pore system. This pressure pulls the solid particles together and decreases the inter-particle distances, causing the whole concrete element to shrink. If this contraction is hindered in any way, the induced tensile stresses may exceed the low tensile strength of the concrete and cracking starts. The phenomenon, occurring shortly after casting while the concrete is still in the plastic stage, is mainly observed in elements with high surface to volume ratio such as slabs and pavements.

    Many parameters may affect the probability of plastic shrinkage cracking. Among others, effect of water/cement ratio (w/c), fines, admixtures, geometry of the element, ambient conditions (i.e. temperature, relative humidity, wind velocity and solar radiation), etc. has been investigated previously. In the presented research, in addition to studying the influence of various parameters, i.e. w/c, cement type, coarse aggregate content, superplasticizer dosage, admixtures, and steel fibres, effort is made to reach a better and more comprehensive understanding about the cracking governing mechanism. Evaporation, capillary pressure evolution and hydration rate are particularly investigated in order to identify their relationship.

    This project started with extensive literature study which is summarized in Paper I. Then, the main objective was set upon which series of experiments were defined. The utilized methods, material, investigated parameters, and results are presented in Papers II-IV. A model was, then, proposed in Paper V, to estimate the cracking severity of the plastic concrete.

    It has been observed that evaporation is the driving force behind the plastic shrinkage crackingin concrete. However, a correlation between evaporation, rate of capillary pressure development and the duration of dormant period governs the severity of the phenomenon. Among other things, the results show that rapid capillary pressure development in the pore network accompanied by slower hydration significantly increases the cracking risk.

  • Navarro, Kevin
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Social Sciences.
    Vårdnadshavares skadeståndsskyldighet: Det strikta ansvaret för barnets skadegörande handlingar2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Sammanfattning

    I huvudkapitel 2-5 redogörs för skadeståndslagstiftningens olika delar. Här beskrivs även den kritik som har funnits mot den reform gällande föräldraansvaret i 3 kap. 5 § skadeståndslagen som kom år 2010. Olika fall tas upp från verkligheten där skadestånd tilldömts. Här finns en beskrivning hur skadeståndsrättens huvudsakliga reparativa syfte införde föräldraansvaret med ett preventivt syfte. Det vill säga att vårdnadshavare aktivt ska försöka förhindra och framförallt förebygga att barnet begår skadevållande handlingar. Brister vårdnadshavaren i detta kan denne åläggas skadeståndsskyldighet. En bristfällig tillsynsplikt kan exempelvis vara att underlåta att ge barnet nödvändiga instruktioner vid användandet av farliga föremål. I detta avseende är förekomsten av föräldranärvaron och de sociala banden av stor betydelse för lagregleringen avseseende föräldrars principalansvar. Men ett enkelt svar på huvudfrågan finns inte. Motiven som berör vårdnadshavaren att förebygga skadegörande handlingar är en kombination mellan de rättsliga reglerna och det kriminalpolitiska ur en kriminologisk aspekt. Möjligen besvaras frågan olika beroende på om fokus ska ligga på tanken om reparation eller prevention. I uppsatsens analys diskuteras bestämmelsen utifrån en kritisk utgångspunkt. Fokus ligger på de faktiska effekterna av bestämmelsen för ekonomiskt svaga familjer samt argumenten för varför ungdomsbrottsligheten inte verkar minska trots förhoppning om en preventiv effekt med skadeståndsrätten.

     

    Sökord: Skadestånd; Vårdnadshavare; Förälder; Principalansvar; Brottsprevention; Jämkning

     

  • Niemi, Magnus
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    GNSS-mätning: idag och i framtiden2019Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    This report shows the difference between today's geodetic measurementsand the one that comes withGalileo and Beidou included. As new GNSSequipment supporting Galileo and Beidou begins to be used, what are the differences and what can be expected by users in the future?This report addresses current theory of sources of error and satellite geometry to highlight the problems associated with GNSS. Based on the sources of error and satellite geometry, the results will be presentedand discussed at the end of the report.

  • Ravindran, Vineetha
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Busatto, Tatiano
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Rönnberg, Sarah
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Meyer, Jan
    Institute of Electrical Power Systems and High Voltage Engineering, Technische Universitaet Dresden, Dresden, Germany.
    Bollen, Math
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Time-varying interharmonics in different types of grid-tied PV inverter systems2019In: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208Article in journal (Refereed)
    Abstract [en]

    Widely existing circuit topologies and inverter control strategies for PV systems allow customer flexibility but also introduce different kinds of interharmonics into the grid. A complete understanding of interharmonics from PV systems, with reasons behind their origin, remains needed. In addition, the timevarying nature of interharmonics and the potential impacts on other equipment are yet to be understood. In this paper, laboratory and field measurements are presented of seven different inverter types at multiple locations. A comprehensive analysis is performed to understand the existence, persistence, and propagation of interharmonics in PV systems on the DC side as well as grid side for different power levels. The origins of the interharmonics are established with experimental evidence and through a comparative analysis. A rural low voltage 6 customer network, with two different impedance profiles caused by the installation of PV, is considered to show the potential impact on customer voltage. To address the time-varying nature of interharmonics, a sliding window ESPRIT method is preferred over FFT based methods

  • Viberg, Frida
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Cirkulär ekonomi inom industriell produktion av flerbostadshus i trä2019Independent thesis Advanced level (professional degree), 300 HE creditsStudent thesis
    Abstract [sv]

    År 2018 inföll ”Overshoot day”, dagen då vi förbrukat årets budget av jordens förnybara resurser, den 1 augusti (Rosengren, 2018). De resterande fem månaderna av året levde vi över jordens tillgångar. Genom att närma oss en cirkulär ekonomi kan vi förvalta jordens resurser på ett sätt som är långsiktigt hållbart och minska behovet av att använda jungfruligt material. Byggsektorn står årligen för ca en tredjedel av allt avfall i Sverige, bortsett från gruvavfallet (Naturvårdsverket, 2017). Just nu pågår en ansträngning i Europa för att minska mängden avfall, där byggbranschen utgör ett prioriterat område. Ett av Europaparlamentets mål är att förberedandet för återanvändning, materialåtervinning och annan återvinning av icke-farligt bygg- och rivningsavfall ska ha ökat till minst 70 viktprocent år 2020 (2008/98/EG).

    Lindbäcks bygg är en av de ledande aktörerna gällande industriellt tillverkade flerbostadshus i trä. Syftet med detta arbete är att genom en fallstudie på Lindbäcks bygg få en ökad förståelse för förutsättningarna för cirkulär ekonomi inom industriell produktion av flerbostadshus i trä. Där fokus ligger på de materialrester som uppstår i fabriksproduktionen och hur dessa hanteras.

    Arbetet inleddes med en litteraturstudie på området cirkulär ekonomi och cirkulär ekonomi inom byggbranschen, avfall och avfallshantering i byggbranschen. Efter emperiinsamlingen fördjupades läsningen mot alternativa lösningar för ökad cirkularitet sett till de tre största rena avfallsfraktionerna. Fallstudien har genomförts genom intervjuer med anställda från olika avdelningar inom Lindbäcks, samt med Lindbäcks avfallsentreprenör. Intervjuerna har kompletterats med data gällande de avfallsmängder som genererats från den studerade fabriken, samt med en kartläggning av överblivet materialet från fyra projekt som producerats i fabrik under vintern 2018.

    Kartläggningen av det överblivna materialet visar på stora skillnader i mängd mellan olika materialtyper och projekt. Mängden överblivet material varierar mellan materialunderskott och ett överskott motsvarande 27 % av det material som köpts in av den aktuella materialtypen för projektet.

    Endast 5 viktprocent av det avfall som genererades i Lindbäcks fabrik i Öjebyn materialåtervanns år 2018. 63 viktprocent av avfallet skickades till förbränning och 30 viktprocent deponerades. De resterande två viktprocenten utgjordes av avfall som klassats som verksamhetsavfall för sortering. För ett uppnå EU-målet med 70 % återvinning krävs alternativa lösningar för hantering av trä-, gips- och isoleringsavfall.

    De alternativa lösningarna för hantering av trä-, gips- och isoleringsavfall som identifierats i litteraturstudien har prioriterats ur ett cirkularitetsperspektiv med hjälp av Re:Sources (Re:Source, 2018) modell för visualisering av materials funktion och användning, materialhjulet. Inom sektorn materialåtervinning återfinns möjliga lösningar för samtliga tre studerade fraktioner. Genom att returnera gipsavfallet till leverantören, riva isoleringsavfallet till lösull och nyttja uppkommet träavfall i tillverkning av biokol, ökar materialåtervinningen från 5 % till 89 %. Detta medför att EU-målet uppnås med marginal, samtidigt som deponi som behandlingsmetod helt elimineras. Som ett hinder för ökad cirkularitet nämns kostnader och utsläpp kopplade till långa transporter. Genom att nyttja outnyttjat utrymme på redan befintliga transporter kan de långa avstånden överbryggas utan extra kostnader och miljöpåverkan.

    Slutsatsen kan dras att genomförandet av ett fåtal förändringar kan få stora effekter, men att fortsatta studier krävs på ämnet cirkulär ekonomi inom byggbranschen.

  • Conrad, Sarah
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Ingri, Johan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Gelting, Johan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Nordblad, Fredrik
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Engström, Emma
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering. ALS Laboratory Group, ALS Scandinavia AB, Luleå, Sweden .
    Rodushkin, Ilia
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering. ALS Laboratory Group, ALS Scandinavia AB, Luleå, Sweden .
    Andersson, Per S.
    Department of Geosciences, Swedish Museum of Natural History, Stockholm, Sweden.
    Porcelli, Don
    Department of Earth Sciences, Oxford University, Oxford, UK.
    Gustafsson, Örjan
    Department of Environmental Science and Analytical Chemistry, Stockholm University, Stockholm, Sweden.
    Semiletov, Igor
    International Arctic Research Center (IARC), University of Alaska, Fairbanks, AK, USA. Pacific Oceanological Institute (POI), Far Eastern Branch of the Russian Academy of Sciences (FEBRAS), Vladivostok, Russia. Tomsk National Research Politechnical University, Arctic Seas Carbon International Research Laboratory, Tomsk, Russia.
    Öhlander, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Distribution of Fe isotopes in particles and colloids in the salinity gradient along the Lena River plume, Laptev Sea2019In: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 16, no 6, p. 1305-1319Article in journal (Refereed)
    Abstract [en]

     Riverine Fe input is the primary Fe source for the ocean. This study is focused on the distribution of Fe along the Lena River freshwater plume in the Laptev Sea using samples from a 600 km long transect in front of the Lena River mouth. Separation of the particulate ( >  0.22 μm), colloidal (0.22 μm–1 kDa), and truly dissolved (<  1 kDa) fractions of Fe was carried out. The total Fe concentrations ranged from 0.2 to 57μM with Fe dominantly as particulate Fe. The loss of >  99% of particulate Fe and about 90% of the colloidal Fe was observed across the shelf, while the truly dissolved phase was almost constant across the Laptev Sea. Thus, the truly dissolved Fe could be an important source of bioavailable Fe for plankton in the central Arctic Ocean, together with the colloidal Fe. Fe-isotope analysis showed that the particulate phase and the sediment below the Lena River freshwater plume had negative δ56Fe values (relative to IRMM-14). The colloidal Fe phase showed negative δ56Fe values close to the river mouth (about -0.20 ‰) and positive δ56Fe values in the outermost stations (about +0.10 ‰). We suggest that the shelf zone acts as a sink for Fe particles and colloids with negative δ56Fe values, representing chemically reactive ferrihydrites. The positive δ56Fe values of the colloidal phase within the outer Lena River freshwater plume might represent Fe oxyhydroxides, which remain in the water column, and will be the predominant δ56Fe composition in the Arctic Ocean.

  • Näslund Anda, Mia
    Luleå University of Technology, Department of Health Sciences, Nursing Care.
    Följsamhet till basala hygienrutiner: Hur uppnår vi det?2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Vårdrelaterade infektioner en av orsakerna till de vårdskador som uppkommer idagens hälso-och sjukvård, vilket leder till stora kostnader för samhällets samt ett stort lidande för patienterna. Följsamhet till de basala hygienrutinerna hos personalen är av största vikt för att hindra-och eller reducera antalet VRI.Syfte:Syftet med denna litteraturstudie är attsammanställabefintlig kun-skap om faktorer som är underlättande/stödjande eller hindrande/försvårande och som påverkar hälso-och sjukvårdspersonalens följsamhet till BHK (basala hygien och klädregler) och därmed stödja eller hindra VRI (vårdrelaterade infektioner).Metod:Totaltingick 10 vetenskapliga ar-tiklar till resultatet i denna litteraturstudie kunskapsöversikt, dessa påträffades i databaserna PubMed och Cinahl med relevanta sökord. Huvudgrupper och subgrupper skapades utifrån en induktiv analysmetod.Resultat:Faktorer sompåverkade följsamheten var lättillgänglighet av handdesinfektion och skyddsutrustning, säkerhetskultur och ökat arbete med systematiska pro-cesser, förebilder och positiv påverkan på kollegor, rädsla att bli smittad, hög personalomsätt-ning/stress, brist på utbildning, negativ påverkan inom arbetsgruppen brist på goda förebilder, systematiska och kontinuerliga kampanjer, återkommande utbildning och interventioner för be-teendeförändringar, ledningens stöd för BHK och kontinuerlig återkoppling samt goda förebil-der/nyckelpersoner.Slutsats:Att ha hög följsamhet till BHK är en utmaning för varje organi-sation. Det krävs multimodala åtgärder för att får resultat. Ledarskapet på alla nivåer blir en vik-tig del i det arbetet.

  • Kampmann, Tobias Christoph
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Ny mineralutställning på gång2019In: Geologiskt Forum, ISSN 1104-4721, Vol. 101, p. 9-9Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    På Luleå tekniska universitet håller vi just nu på med att skapa en modern mineralutställning som visar den geologiska forskningen vid universitetet, men som också ska väcka intresse för prospektering och industriprocesser kopplade till mineral och metallurgi.

  • Duvnjak, Ivan
    et al.
    University of Zagreb, Croatia.
    Damjanović, Domagoj
    University of Zagreb, Croatia.
    Sabourova, Natalia
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Grip, Niklas
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mathematical Science.
    Ohlsson, Ulf
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Tu, Yongming
    School of Civil Engineering, Southeast University, Nanjing, China.
    Damage Detection in Structures – Examples2019In: IABSE Symposium 2019: Towards a Resilent Built Environment - Risk and Asset Management, 2019Conference paper (Refereed)
    Abstract [en]

    Damage assessment of structures includes estimation of location and severity of damage. Quite often it is done by using changes of dynamic properties, such as natural frequencies, mode shapes and damping ratios, determined on undamaged and damaged structures. The basic principle is to use dynamic properties of a structure as indicators of any change of its stiffness and/or mass. In this paper, two new methods for damage detection are presented and compared. The first method is based on comparison of normalised modal shape vectors determined before and after damage. The second method uses so-called 𝑙1-norm regularized finite element model updating. Some important properties of these methods are demonstrated using simulations on a Kirchhoff plate. The pros and cons of the two methods are discussed. Unique aspects of the methods are highlighted.

  • Sabourova, Natalia
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Grip, Niklas
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mathematical Science.
    Ohlsson, Ulf
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Tu, Yongming
    School of Civil Engineering, Southeast University, Nanjing, China.
    Duvnjak, Ivan
    University of Zagreb, Croatia.
    Damjanović, Domagoj
    University of Zagreb, Croatia.
    Detection of Sparse Damages in Structures2019In: IABSE Symposium 2019: Towards a Resilent Built Environment - Risk and Asset Management, 2019Conference paper (Refereed)
    Abstract [en]

    Structural damage is often a spatially sparse phenomenon, i.e. it occurs only in a small part of the structure. This property of damage has not been utilized in the field of structural damage identification until quite recently, when the sparsity-based regularization developed in the compressed sensing found its application in this field.

    In this paper we consider classical sensitivity-based finite element model updating combined with a regularization technique appropriate for the expected type of sparse damage. Traditionally (1) 𝑙2-norm regularization was used to solve the ill-posed inverse problems, such as damage identification. However, using (2) already well established 𝑙1-norm regularization or (3) our proposed 𝑙1-norm total variation regularization and (4) general dictionary-based regularization allows us to find damages with special spatial properties quite precisely using much fewer measurement locations than the number of possibly damaged elements of the structure. The validity of the proposed methods is demonstrated using simulations on a Kirchhoff plate model. The pros and cons of these methods are discussed.

  • Public defence: 2019-04-29 13:00 E231, Luleå
    Allali, Naoual
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Covalent functionalization of carbon nanomaterials for bioelectrochemical applications2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Carbon nanotubes (CTNs) are renowned for their exceptional electronic and mechanical properties. Their structure can be considered as rolling up a graphene sheet along a specific crystallographic direction, leading to a 1D confinement of the electronic wavefunction of the delocalized electrons along the perimeter of the cylindrical structure thus obtained. This confinement produces the existence of defined spikes of high intensity in the electronic density of states, called van Hove singularities. These singularities are primordial to understand both the optical and electronic properties of CNTs through electronphonon coupling processes. If the electronic density of states (DoS) is non zero at the Fermi level the nanotube is metallic, otherwise the nanotube is semiconducting. The synthesis of CNTs always produces a mixture of both metallic and semiconducting nanotubes, and this material can be useful to be incorporated at the surface of electrodes for electrochemical devices. The high specific surface area, the high mechanical and thermal stability of CNTs and the low percolation threshold for electron transport in a mat of CNTs render them very attractive for such kind of applications. There is yet a drawback of using raw CNTs: they are not compatible with solvents and modification of their surfaces by chemistry is required to make good suspensions for easy deposition at the electrode surface and to introduce specific functional groups for promoting electron transfer, called electron shuttles.

    The final aim of this thesis is therefore the covalent functionalization of CNTs by electron shuttles and their incorporation at the surface of glassy carbon electrodes for electrochemical devices application. A strategy of chemical grafting in three steps has been chosen: i) a controlled oxidation step in acidic media assisted by microwave irradiation in order to keep the structural integrity of CNTs, so as to save their useful electronic properties; ii) a chloration step to produce acid chloride groups and iii) reaction of these groups with electron shuttles modified by specific linkers. The study was first conducted on very clean HiPCO single-walled CNTs (SWCNTs). This enabled to avoid any disturbing effects of carbonaceous impurities or residual catalytic particles, since their possible effects are extremely controversial in the literature. Once validated, this approach was then conducted with cheaper material including few-walls carbon nanotubes (FWCNTs). The use of FWCNTs compared to SWCNTs was not only beneficial for the production of costeffective electrochemical devices but also for a better durability ofthe final device, the inner nanotubes being not functionalized.

    The challenge was to obtain a functionalization process with enough grafted electron shuttles to obtain a good electrocatalytic activity but maintaining CNTs integrity. The first step is predominant to reach this goal, and requires a very accurate understanding of the nature and the number of defects created in the CNTs structure versus the physico-chemical conditions used. The introduction of defects in the crystallographic structure of CNTs has strong consequences both for the electronic DoS and for the phononic properties of the material. Spectroscopic methods are essential in probing these consequences. UV-visible-near IR absorption spectroscopy is the method of choice to directly probe the existence of van Hove singularities and the oscillator strength associated with the authorized electronic transitions between theses ingularities. Covalent grafting of chemical groups at the surface of CNTs changes both the energy and the intensity of these transitions. However, this spectroscopic method requires solubilizing CNTs in non-absorbing solvents using adequate surfactants. Interactions between surfactant molecules and CNT sidewalls may also alter the position and intensity of electronic transitions between van Hove singularities unrelated to the chemical groups covalently grafted.

    Raman spectroscopy of CNTs involves the electronphonon coupling processes through the resonant electronic enhancement of Raman modes. Double resonance processes are also observed in Raman spectrum of CNTs, for instance with the D-band mode that is actually related to the existence of defects in the graphene structure of CNTs. Therefore, Raman spectroscopy is a widespread analytical method to characterize the structural defects created by covalent functionalization processes. Indeed, the intensity ratio of the D and G bands in the Raman spectrum is correlated to the number of defects. However, CNTs are used as bundles when chemical functionalization is performed, which produces a heterogeneous distribution of chemical species grafted on CNTs. Therefore, we have developed a new protocol to obtain statistically significant data for most of the samples made in this thesis. Nevertheless, this statistical approach is still limited for samples slightly functionalized, whence the idea to use spectroscopic ellipsometry as an alternative method to characterize these samples.

    More specifically, ellipsometric data were collected from UV to the IR part of the electromagnetic spectrum for CNTs functionalized in different conditions. The complex dielectric function was retrieved from the experimental data. A Drude model was used to model the infrared part of the data for raw and acid oxidized CNTs. The optical conductivity of the samples was obtained. These results, combined with other information collected using a set of complementary analytical techniques (Raman scattering, UV-visible-NIR absorption, X-ray photoelectron spectroscopy, thermogravimetric analysis coupled to mass spectrometry, transmission electron microscopy and rare gas volumetric adsorption), show that the microwave-assisted oxidation process actually consists in removing amorphous carbon deposits away from the surface of CNTs and transforming the already existing defects in the CNT structure to oxygen-containing groups such as carboxylic acids.

    Rare gas volumetric adsorption was also used to compare the distribution of chemical groups at the surface of CNT bundles when two different acids are used (HNO3 and H2SO4). The chloration step was also studied by these methods, as well as the final grafting of electron shuttles. Finally, these functionalized CNTs were deposited at the surface of glassy carbon electrodes and used as electron mediators for diaphorase-catalysed oxidation of nicotinamide adenine dinucleotide (NADH). This was a good example of mediated electron transfer for development of electrochemical devices based on NADH recycling and it validated the good electrocatalytic properties of functionalized CNTs for making electrochemical sensors and actuators, opening new perspectives with potential market applications.

  • Siraj, Shabna
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    ARCTIC: An IoT-based System for Child Tracking in Day Care2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • Rikberg, Heidi
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Field damage investigation and evaluation of numerical model using the collected data at Kemi Mine2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This Master´s Thesis studies the applicability of existing numerical model to predict the conditions in the drifts at the mine. Damage mapping, covering the existing production levels, has been carried out to study the condition of the surface support, i.e. shotcrete, mesh and rock bolts to quantify the amount of deformation visible in the tunnels. Irregularities in the floor levels were also mapped.

    The rock support applied varies between different areas, from only a layer of shotcrete to areas where shotcrete, mesh and cable bolts are applied sequentially. The large amount of support in some regions is required because of high in situ rock stresses in Kemi Mine. The geological conditions are challenging, with large local variation making efficient supporting and damage prediction difficult. Access drifts at the mine have varying service times, on average 6 years, which is a long time in a difficult environment.

    The results from this work are a mine specific damage classification, used in the mapping to capture the range of damages seen on site. A reoccurrence of same areas showing damages on several production levels is noted. Digitized versions of the damage maps were made and these have been compared to simulation results. The comparisons were made to plots of deviatoric strain, deviatoric stress and total displacement.

    Based on the work done during this project it can be concluded that the studied parameters have varying levels of agreement with the drifts, both when comparing the levels with each other and the results in the same level between spring and autumn. The best agreement is found with the deviatoric strain increment and the yielded elements. Rock mechanics and geological reasons for the variations seen between the mapping results and the simulations results can be further studied in the future, as can the alternatives for increasing the accuracy through changes in the numerical model or model type used for comparison.