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  • Hedkvist, Anton
    et al.
    Luleå University of Technology, Department of Health, Learning and Technology.
    Haraldson, Linda
    Luleå University of Technology, Department of Health, Learning and Technology.
    Personers upplevelser av att leva med reumatoid artrit: en litteraturstudie2023Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Bakgrund: Reumatoid artirt (RA) är den vanligaste typen av ledinflammationer. Ungefär 100 000 personer i Sverige lever idag med RA. Sjukdomen börjar oftast med en symmetrisk inflammation i de mindre lederna och personer som drabbas av sjukdomen upplever ofta smärta, trötthet, svullna och stela leder. Syfte: Beskriva personers upplevelser av att leva med reumatoid artrit. Metod: Litteratursökning genomfördes systematiskt i databaserna PubMed och Cinahl. Detta resulterade i 13 vetenskapliga artiklar som analyserades genom en kvalitativ manifest innehållsanalys med induktiv ansats. Resultat: Analysen resulterade i fyra slutkategorier: Att leva med symtom som trötthet, smärta, stela och svullna leder, Att känna en begränsning i det sociala livet, Att känna oro, ilska och frustration över sin situation, Att lära sig leva med sjukdomen. Slutsats: Resultatet visade att symtomen som personer upplevde påverkade livskvaliteten. Symtomen kunde visa sig olika, allt från symtom vissa dagar, till att symtomen var ständigt närvarande, eller komma i skov. Många upplevde sig oroliga, ilskna och frustrerade eftersom det är en kronisk sjukdom de har drabbats av. Vardagen förändrades för personer vilket påverkade det sociala livet, de undvek sociala relationer, sysselsättningar och arbete. I och med att RA är en kronisk sjukdom så förstod personer att de måste lära sig att leva med sjukdomen, även om det kunde upplevas som svårt. Slutsatsen av litteraturstudien blev att förståelsen ökade kring hur det är att leva med RA för drabbade personer, sjukvårdspersonal och även samhället i stort.

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  • Wessling, Albin
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Solid Mechanics.
    Larsson, Simon
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Solid Mechanics.
    Kajberg, Jörgen
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Solid Mechanics.
    A statistical bonded particle model study on the effects of rock heterogeneity and cement strength on dynamic rock fracture2023In: Computational Particle Mechanics, ISSN 2196-4378Article in journal (Refereed)
    Abstract [en]

    Numerical modelling and simulation can be used to gain insight about rock excavation processes such as rock drilling. Since rock materials are heterogeneous by nature due to varying mechanical and geometrical properties of constituent minerals, laboratory observations exhibit a certain degree of unpredictability, e.g. with regard to measured strength and crack propagation. In this work, a recently published heterogeneous bonded particle model is further developed and used to investigate dynamic rock fracture in a Brazilian disc test. The rock heterogeneities are introduced in two steps—a geometrical heterogeneity due to statistically distributed grain sizes and shapes, and a mechanical heterogeneity by distributing mechanical properties using three Weibull distributions. The first distribution is used for assigning average bond properties of the grains, the second one for the intragranular bond properties and the third one for the bond properties of the intergranular cementing. The model is calibrated for Kuru black diorite using previously published experimental data from high-deformation rate tests of Brazilian discs in a split-Hopkinson pressure bar device, where high-speed imaging was used to detect initiations of cracks and their growth. A parametric study is conducted on the Weibull heterogeneity index of the average bond properties and the grain cement strength and evaluated in terms of crack initiation and propagation, indirect tensile stress, strain and strain rate. The results show that this modelling approach is able to reproduce key phenomena of the dynamic rock fracture, such as stochastic crack initiation and propagation, as well as the magnitude and variations of measured quantities. Furthermore, the cement strength is found to be a key parameter for crack propagation path and time, overloading magnitudes and indirect tensile strain rate.

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  • Olsson, Erik
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Solid Mechanics. Department of Solid Mechanics, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
    Jelagin, Denis
    Department of Civil and Architectural Engineering, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
    Larsson, Stefan
    Department of Civil and Architectural Engineering, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
    Chen, Feng
    Department of Civil and Architectural Engineering, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden; Department of Highway and Railway Engineering, School of Transportation, Southeast University, Nanjing, People’s Republic of China.
    A numerical framework for modelling settlements of railway ballast layers2024In: Transportation Geotechnics, ISSN 2214-3912, Vol. 44, article id 101140Article in journal (Refereed)
    Abstract [en]

    Permanent deformation in ballast layers is a major contributing factor to the railway track geometry deterioration. In spite of a considerable amount of research on understanding and predicting performance of ballast layers, accurately capturing their settlements remains a challenge. In order to contribute to solving this important issue, a new numerical method for predicting ballast settlements is presented in this paper. This method is based on the finite element (FE) method combined with a constitutive model that captures permanent deformation accumulation in unbound materials under cyclic loading. This allows predicting permanent deformations of large structures and at large number of load cycles in a computationally efficient manner.

    The developed constitutive model is validated based on triaxial test measurements over wide range of loading conditions. Stress state in ballast layers has been examined with a 3D FE model, for several embankment structures and traffic load magnitudes. The determined stress distributions and loading frequencies were used as an input of the constitutive model to evaluate permanent strains and settlements of ballast layer. The influence of embankment structural designs and traffic loading magnitudes on the ballast layers settlements is examined and the results obtained are compared with the existing empirical performance models.

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  • Marklund, Elisabeth
    et al.
    Luleå University of Technology, Department of Health, Learning and Technology.
    Högberg, Linda
    Luleå University of Technology, Department of Health, Learning and Technology.
    Kvinnors upplevelse av att drabbas av en förlossningsskada: en litteraturstudie2023Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Bakgrund: Att drabbas av en förlossningsskada och efterföljande komplikationer är ett trauma som drabbar cirka 85% av kvinnor som genomgår en vaginalförlossning, framförallt förstföderskor. Bristningar i underlivet är vanligt förekommande men kan ta lång tid innan diagnos ställs. Smärta och fysiska och psykiska begränsningar är vanliga komplikationer som påverkar kvinnans livskvalitet. Syfte: Litteraturstudiens syfte var att beskriva kvinnors upplevelser av att drabbas av en förlossningsskada. Metod: Litteraturstudien genomfördes systematiskt i databaserna PubMed och Cinhal. Sökningen resulterade i 17 vetenskapliga artiklar som analyserades genom kvalitativ manifest innehållsanalys med induktiv ansats. Resultat: Att kvinnor med förlossningsskada upplevde att hela livet påverkades av skadan. Kvinnorna hade mestadels negativa erfarenheter av hälso- och sjukvården, många besvärliga kroppsliga och psykologiska symtom, problem med relationen till partner samt svårigheter i det dagliga livet. Slutsats: Att kvinnohälsa är ett viktigt område inom vården som innehåller kunskapsluckor. Mer kunskap krävs både av och för vårdpersonalen om förlossningsskador för att förbättra möjligheten för kvinnor att få rätt vård och stöd i sin väg mot återhämtning. Kvinnor med förlossningsskada ska inte behöva lida av svåra symtom på grund av okunskap från hälso- och sjukvården.

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  • Hermansson, Sofia
    et al.
    Luleå University of Technology, Department of Health, Learning and Technology.
    Wahlin, Nina
    Luleå University of Technology, Department of Health, Learning and Technology.
    Rustad att leda! Sjuksköterskors erfarenheter av ledarskap inom slutenvården: En litteraturstudie2023Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Bakgrund: Ledarskap är en del av sjuksköterskans kärnkompetenser. Sjuksköterskors ledarskap finns i många kontexter, bland annat inom slutenvården. Ledarskapet är viktigt för att det påverkar vården och omvårdnaden av patienter. Inom slutenvården utmanas ledarskapet utifrån samarbeten, förändring, organisatoriska resurser och varierande grad av kompetens hos sjuksköterskor och deras medarbetare. Syfte: Att beskriva sjuksköterskors erfarenheter av ledarskap inom slutenvården. Metod: Författarna har genomfört en litteraturstudie med induktiv ansats. Kvalitativ manifest innehållsanalys användes som metod för dataanalysen. Resultat: Fyra kategorier utgör resultatet: “Bilden av ledaren och det goda ledarskapet är komplex”, “Sjuksköterskors ledarskap påverkar samarbeten”, “Sjuksköterskors ledarskap påverkar omvårdnaden" och “Sjuksköterskors ledarskap påverkar och påverkas av förändring och kris” Slutsats: Ledarskapets komplexitet utifrån sjuksköterskors förutsättningar kräver anpassning till vårdkontext, sjuksköterskans egenskaper och omgivningens förväntningar. Ledarskapet påverkar samarbetet inom vården och utmanas under förändring och kris. Utbildning och stöd för sjuksköterskor är avgörande för att utveckla ledarskapsfärdigheter och säkerställa högkvalitativ omvårdnad. Framtida forskning bör fokusera på att utifrån sjuksköterskors perspektiv utforska olika innovativa strategier för ledarskapsutveckling samt metoder för att hantera utmaningar som kan uppstå i en miljö präglad av förändring och kris.

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  • Zvarivadza, Tawanda
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Numerical Modelling Application in the Management of Deep Mining Excavation Stresses: An Illustrative Study2023In: Mining, E-ISSN 2673-6489, Vol. 3, no 4, p. 731-754Article in journal (Refereed)
    Abstract [en]

    Numerical modelling is an important instrument for rock engineering; it can assist in the design and prediction of failure in rock masses. Dependable results can be obtained from the models if, and only if, the underlying assumptions, strengths, and weaknesses of the model are known. A set of guidelines to implement a numerical modelling program can also be used to obtain high-quality and reliable results. The importance of a well-structured numerical modelling program to attain practically reasonable results cannot be overstated. This paper presents an analysis of the results of modelling a rock engineering problem involving deep mining excavations prone to high-stress challenges. The study used Lamodel and Examine 2D. The results obtained show that the two software programs can be used together to complement each other in attaining a deeper understanding of the influence of high stresses on mining excavations at depth. Lamodel and Examine 2D are both boundary element code-based software and are quick and easy to use. More advanced numerical modelling tools could be used, but these two were found to be suitable for the problem at hand. Many diagrams and results can be obtained from the numerical modelling of any rock engineering challenge; in this paper, only those diagrams and results deemed to be most relevant and appropriate to demonstrate the capabilities, limitations, and validity of the numerical modelling of the problem have been presented.

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  • Pyykkö, Rebecka
    Luleå University of Technology, Department of Health, Learning and Technology.
    Upplevelser av Virtual Reality i rehabiliteringen hos strokepatienter: En metasyntes2023Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Background: The number of people who suffer a stroke is increasing all over the world, and thus the healthcare system is faced with a continuing challenge to develop and modernize the rehabilitation for stroke patients. 

    Aim: To review and synthesize literature on how stroke patients experience Virtual Reality (VR) in rehabilitation and its possible impact on the ability to perform activities in everyday life. 

    Method: A systematic literature review to review and compile literature. The databases used for the collection of the articles are CINAHL, Medline, PubMed, Taylor & Francis Journals, AMED and PsycInfo, which resulted in 9 studies. The review of the articles was carried out according to the SBU’s review model on assessment of studies with qualitative methodology. After the quality review, a meta-synthesis was made of the included articles to answer the purpose of the study. 

    The result: The literature review contains 9 studies with publication years 2015–2022. The meta- synthesis led to 24 first-level themes and four second-level themes: "VR creates positive and negative experiences", "Perceived advantages and disadvantages of using VR among stroke patients", "Improvement of functional ability in everyday life with the help of VR" and "The importance of context and support are emphasized”. An analysis of the second-level themes resulted in two third-level themes: "VR arouses interest, but has advantages as well as disadvantages" and "VR's importance in everyday life and social life for stroke patients". 

    Conclusion: The review of the material resulted in 9 studies. On the basis of the studies, positive and negative experiences of VR in stroke patients emerged, among other things. Based on the study, there also remains a need for continued qualitative studies within the subject, which focus on stroke patients and their experiences of VR in order to contribute to an increased knowledge of the subject from an occupational therapy perspective. 

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  • Andersson, Anton
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Brander, Linus
    Research Institute of Sweden, Division of Built Environment – Infrastructure and Concrete, Box 857, SE-501 15 Borås, Sweden.
    Lennartsson, Andreas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Roos, Åke
    Boliden Smelters, Boliden AB, Klarabergsviadukten 90, SE-101 20, Stockholm, Sweden.
    Engström, Fredrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Ground granulated iron silicate slag as supplementary cementitious material: Effect of prolonged grinding and granulation temperature2023In: Cleaner Materials, E-ISSN 2772-3976, Vol. 10, article id 100209Article in journal (Refereed)
    Abstract [en]

    The metallurgical and cement industries contribute significantly to anthropogenic carbon dioxide emissions. Utilizing oxidic by-products from the metallurgical industry as supplementary cementitious materials (SCMs) can improve resource efficiency and reduce emissions from cement production. Iron silicate copper slags have been studied as SCMs, but mainly in systems where Portland cement is used as an activator. There is limited research on the inherent reactivity of the slag under changing processing conditions. The present study offers insight into the effect of granulation temperature and grinding on the inherent reactivity of an industrially produced iron silicate copper slag. The results showed that granulation temperature had an insignificant effect on reactivity, while grinding generated substantial improvements. The latter effect was concluded to stem from the increased specific surface area, increased number of sites for nucleation and growth of hydrates, and changes in the inherent reactivity owing to structural changes induced by the grinding.

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  • Eriksson, Rebecka
    et al.
    Luleå University of Technology, Department of Health, Learning and Technology.
    Datmo, Angelica
    Luleå University of Technology, Department of Health, Learning and Technology.
    Mobil radiografi och omställningen till nära vård: En enkätstudie riktad till röntgensjuksköterskor2023Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Introduktion: En god och nära samt mer personcentrerad vård har förutsättning att gagna våra mest sköra patienter, vilket gör ämnet relevant för professionen. Utvecklingen av mobila team i form av mobil radiografi ligger därmed i linje med nära vård. Röntgensjuksköterskors inställning till och erfarenheten av utvecklingen av mobila arbetssätt är ännu ett relativt outforskat område. Syfte: Att undersöka attityden till och erfarenheten av mobil radiografi bland yrkesverksamma röntgensjuksköterskor. Metod: En egenkonstruerad digital enkätundersökning riktad till röntgensjuksköterskor. 72 respondenter besvarade enkäten. Resultat: Majoriteten av de 72 respondenterna har aldrig arbetat med mobil radiografi. Av de 19 respondenter som har arbetat med detta arbetssätt tidigare kan majoriteten tänka sig att arbeta med detta i framtiden. Vidare är 54% av samtliga respondenter positivt inställda till att arbeta med mobil radiografi i framtiden. De respondenter som varit yrkesverksamma under 5–10 år är mest positiva till detta arbetssätt och de respondenter som varit yrkesverksamma i färre än 5 år är mest tveksamma. Slutsats: Respondenterna upplever mobil radiografi som ett arbetssätt som potentiellt kan bidra till en mer personcentrerad och nära vård.

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  • Ma, Chunyan
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Wang, Yanxin
    State Key Laboratory of Material-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 210009, PR China.
    Sun, Yunhao
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Lu, Xiaohua
    State Key Laboratory of Material-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 210009, PR China.
    Ji, Xiaoyan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Thermodynamic study of imidazolium halide ionic liquid–water binary systems using excess Gibbs free energy models2023In: Journal of Molecular Liquids, ISSN 0167-7322, E-ISSN 1873-3166, Vol. 391, Part B, article id 123337Article in journal (Refereed)
    Abstract [en]

    In this work, the excess Gibbs free energy models, i.e., non-random two-liquid (NRTL) model and electrolyte NRTL model, including the original one and those with new strategies (association or hydration), were used to describe the macroscopic properties and interpret the microstructure of ionic liquid (IL) - H2O binary systems, clarifying the role of IL association and ion hydration in model development. To provide systematic data for model development, the enthalpy of mixing of three imidazolium-based IL-H2O systems containing the same cation but different sizes of anions, i.e., Cl−, Br−, and I−, were measured. The models were developed and evaluated based on the newly measured data and the osmotic coefficient from the literature. The results reveal that the model reflecting the intrinsic mechanism of dissociation and hydration gives the best modeling results; and the ionic strength and the degree of IL dissociation as a function of water content can be predicted using the newly established model. The study clarifies the significance of IL association and anion hydration in model development and quantitatively demonstrates how water content influences the microstructure and real species in IL-H2O systems.

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  • Colombo, Simone
    et al.
    Umeå University, Umeå, Sweden.
    Hansson, Patrik
    Umeå University, Umeå, Sweden.
    Nyström, Markus B.T.
    Luleå University of Technology, Department of Health, Learning and Technology, Health, Medicine and Rehabilitation.
    Mining players’ experience in computer games: Immersion affects flow but not presence2023In: Computers in Human Behavior Reports, E-ISSN 2451-9588, Vol. 12, article id 100334Article in journal (Refereed)
    Abstract [en]

    Understanding how different levels of immersion influence the experiences of flow and presence can shed light on the intricate interplay between these constructs and provide valuable insights into the factors that contribute to engaging and immersive gameplay. The independent variable, immersion, was manipulated in three conditions (high, moderate, and low) in a between-subject design within the video game Minecraft. Participants were asked to complete 15 min of gameplay and then fill out the questionnaires concerning flow and presence. The experiment was conducted remotely on a video-sharing platform. Bayesian analysis revealed an effect of immersion level on flow, while no evidence of an effect was found for the experience of presence. This study provides evidence in favor of a relation between flow and immersion while supporting a presumed double dissociation of immersion from presence. Future research using a Bayesian approach is encouraged to build further knowledge on this research topic.

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  • Lundin, Ludvig
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Erfarenhetsåterföring inom den projektbaserade byggbranschen: En intervjustudie av två besläktade projekt2023Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Byggbranschen idag har stora utmaningar med slöseri av resurser och återkommande fel under produktionsfasen nämns som ett allvarligt problem. Genom att utveckla entreprenörers erfarenhetsåterföring kan den projektbaserade branschen på sikt minska det totala svinnet. Denna studie syftar till att undersöka de aktiviteter som en svensk entreprenör genomför under två projekt. Målet är att presentera rekommendationer om hur projektbaserade entreprenörer inom byggbranschen bör lägga upp processen för genomförandet av erfarenhetsåterföring. Detta ska svaras på genom två frågeställningar:

    1.     Hur har erfarenhetsåterföringen gått till i den undersökta intervjustudien av två besläktade projekt?

    2.     Vad karaktäriserar en god erfarenhetsåterföring inom en projektbaserad organisation?

    En litteraturstudie visade på kunskap och organisatoriskt lärande som de bakomliggande begreppen som styr erfarenhetsåterföringen. Undersökningen gjordes sedan som en intervjustudie baserad på intervjuer av tjänstepersoner som är involverade i det dagliga arbetet på byggarbetsplatsen. De fick berätta om det arbetet som genomförs för att ta vara på de kunskaper som produceras under projekten och föra vidare det i organisationen. De aktiviteter som identifierades under intervjuerna analyserades genom teoretisk tematisk analys. Olika delar av organisatoriskt lärande; förvärv av kunskap, distribution av information, tolkning av information och organisatoriskt minne; låg som grund för tematiseringen av de olika aktiviteterna. Totalt identifierades under intervjuerna tolv aktiviteter som ansågs ha en påverkan på projektens erfarenhetsåterföring. Tre tematiserades som förvärv av kunskap, en som distribution av information, tre som tolkning av information och fem som organisatoriskt minne. Med hjälp av en identifierad definition av erfarenhetsåterföring kunde sedan antalet aktiviteter som faktiskt utgör erfarenhetsåterföring i de aktuella projekten begränsas till tio stycken. Dessa aktiviteter bidrog i olika omfattning positivt till organisationens framtida resultat.

    För att klara av att genomföra en effektiv erfarenhetsåterföring i byggbranschen kunde denna studie konstatera att mängden dokumentation och information som förs vidare från ett enskilt projekt kraftigt behöver begränsas. Om lärdomar och kunskaper på ett användbart sätt ska gå att förmedla från ett projekt vidare i organisationen är det vara nödvändigt att begränsa informationsflödet. Genom att fokusera projektets lärande på en enstaka eller ett fåtal pilotundersökningar går det att skapa bättre strukturer och mer genomtänkta metoder för analyser och tolkningar. Med detta tillvägagångssätt kommer en hel del information att ignoreras under projektets gång, men det säkerställer kvalitén på det som faktiskt distribueras vidare i organisationen. 

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  • Zhang, Qiyuan
    et al.
    School of Psychology, Cardiff University, 70 Park Place, Cardiff CF10 3AT, UK; Cardiff University Centre for AI, Robotics and Human-Machine Systems (IROHMS), United Kingdom; Human Factors Excellence (HuFEx) Research Group, United Kingdom; Cardiff University Digital Transformation Innovation Institute (DTII), United Kingdom.
    Wallbridge, Christopher D.
    School of Computer Science & Informatics, Abacws, Senghennydd Road, Cardiff CF24 4AG, UK; Cardiff University Centre for AI, Robotics and Human-Machine Systems (IROHMS), United Kingdom.
    Jones, Dylan M.
    School of Psychology, Cardiff University, 70 Park Place, Cardiff CF10 3AT, UK; Cardiff University Centre for AI, Robotics and Human-Machine Systems (IROHMS), United Kingdom; Human Factors Excellence (HuFEx) Research Group, United Kingdom.
    Morgan, Phillip
    Luleå University of Technology, Department of Health, Learning and Technology, Health, Medicine and Rehabilitation. School of Psychology, Cardiff University, 70 Park Place, Cardiff CF10 3AT, UK; Cardiff University Centre for AI, Robotics and Human-Machine Systems (IROHMS), United Kingdom; Human Factors Excellence (HuFEx) Research Group, United Kingdom; Cardiff University Digital Transformation Innovation Institute (DTII), United Kingdom.
    Public perception of autonomous vehicle capability determines judgment of blame and trust in road traffic accidents2024In: Transportation Research Part A: Policy and Practice, ISSN 0965-8564, E-ISSN 1879-2375, Vol. 179, article id 103887Article in journal (Refereed)
    Abstract [en]

    Road accidents involving autonomous vehicles (AVs) will not only introduce legal challenges over liability distribution but also generally diminish the public trust that may make itself manifested in slowing the initial adoption of the technology and call into question the continued adoption of the technology. Understanding the public’s reactions to such incidents, especially the way they differentiate from conventional vehicles, is vital for future policy-making and legislation, which will in turn shape the landscape of the autonomous vehicle industry. In this paper, intuitive judgments of blame and trust were investigated in simulated scenarios of road-traffic accidents involving either autonomous vehicles or human-driven vehicles. In an initial study, five of six scenarios showed more blame and less trust attributed to autonomous vehicles, despite the scenarios being identical in antecedents and consequences to those with a human driver. In one scenario this asymmetry was sharply reversed; an anomaly shown in a follow-up experiment to be dependent on the extent to which the incident was more likely to be foreseeable by the human driver. More generally these studies show—rather than being the result of a universal higher performance standard against autonomous vehicles—that blame and trust are shaped by stereotypical conceptions of the capabilities of machines versus humans applied in a context-specific way, which may or may not align with objectively derived state of affairs. These findings point to the necessity of regularly calibrating the public’s knowledge and expectation of autonomous vehicles through educational campaigns and legislative measures mandating user training and timely disclosure from car manufacturers/developers regarding their product capabilities.

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  • Fadaei Naeini, Vahid
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements. Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Björling, Marcus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Larsson, Andreas
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Larsson, Roland
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Unraveling the pressure-viscosity behavior and shear thinning in glycerol using atomic scale molecular dynamics simulations2023In: Journal of Molecular Liquids, ISSN 0167-7322, E-ISSN 1873-3166, Vol. 390, no part A, article id 122990Article in journal (Refereed)
    Abstract [en]

    In order to increase the usage and explore new applications of glycerol as a replacement for fossil-based lubricants its properties needs to be known at the fundamental level. In this study, the viscosity of pure glycerol at high pressures and strain rates has been investigated using of molecular dynamics (MD) simulations, utilizing both the Green-Kubo (GK) formalism and the SLLOD algorithm. Although the viscosity acquired by the GK method is in agreement with the corresponding experimental values at low pressure, a significant distinction was identified between the viscosity obtained by the GK method and the experimental values at higher pressures (P > 0.5 GPa). This results in a clear difference between the viscosity-pressure coefficient attained by the GK method and the corresponding experimental value. The SLLOD method using a non-equilibrium MD (NEMD) platform was exploited to take into account the simultaneous effects of strain rate and pressure on viscosity. As a result, the pressure-viscosity coefficient acquired by the SLLOD algorithm approaches the experimental value. By combining the experimental outputs for viscosity at low strain rates ( < 104 s−1) with the SLLOD outputs at higher rates ( > 105 s−1), the evolutions of glycerol viscosity with pressure and strain rate were ultimately achieved. Implementing this computational platform depicts the shear thinning process in pure glycerol in a wide range of pressures and strain rates.

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  • Koti, Daniel
    et al.
    Faculty of Engineering, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom.
    Powell, John
    Faculty of Engineering, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom; University of Stuttgart, ICM, D-70569 Stuttgart, Germany.
    Naesstroem, Himani
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Spaccapaniccia, Chiara
    Independent Researcher.
    Voisey, K. T.
    Faculty of Engineering, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom.
    Laser cladding: A high-speed-imaging examination of powder catchment efficiency as a function of the melt pool geometry and its position under the powder stream2023In: Journal of laser applications, ISSN 1042-346X, E-ISSN 1938-1387, Vol. 35, no 4, article id 042065Article in journal (Refereed)
    Abstract [en]

    This paper provides quantitative information about the paths taken by blown powder particles during laser cladding. A proportion of the powder is "wasted" by bouncing off the solid areas surrounding the melt pool. This wastage reduces the productivity and profitability of the process. In this paper, specially developed software was used to analyze high-speed imaging videos of the cladding process, to monitor the directions of powder particle flight toward and away from the melt pool area. This information has been correlated to the geometry and position of the melt pool zone for three different cladding techniques: single track cladding (A tracks), standard overlapping track cladding (AAA cladding), and a recently developed technique called ABA cladding. The results show that the melt pool geometry, and particularly the overlap between the melt pool and the incoming powder stream, has a strong influence on powder catchment efficiency. ABA cladding was found to have considerably better powder catchment efficiency than standard AAA cladding and this improvement can be explained by consideration of the geometries and positions of the melt pools and surrounding solid material in each case. As powder costs are an important factor in industrial laser cladding, the adaption of the ABA technique, and/or control of pool/powder stream overlap (e.g., by making the powder stream not coaxial with the laser beam), could improve the profitability of the process.

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  • Mesfun, Sennai
    et al.
    RISE Research Institutes of Sweden, P.O. Box 5604, 114 86 Stockholm, Sweden.
    Gustafsson, Gabriel
    Bioshare AB, 655 92 Karlstad, Sweden.
    Larsson, Anton
    Bioshare AB, 655 92 Karlstad, Sweden.
    Samavati, Mahrokh
    Department of Energy Technology, KTH Royal Institute of Technology, 100 44 Stockholm, Sweden.
    Furusjö, Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science. RISE Research Institutes of Sweden, P.O. Box 5604, 114 86 Stockholm, Sweden.
    Electrification of Biorefinery Concepts for Improved Productivity—Yield, Economic and GHG Performances2023In: Energies, E-ISSN 1996-1073, Vol. 16, no 21, article id 7436Article in journal (Refereed)
    Abstract [en]

    Demand for biofuels will likely increase, driven by intensifying obligations to decarbonize aviation and maritime sectors. Sustainable biomass is a finite resource, and the forest harvesting level is a topic of ongoing discussions, in relation to biodiversity preservation and the short-term role of forests as carbon sinks. State-of-the-art technologies for converting lignocellulosic feedstock into transportation biofuels achieves a carbon utilization rate ranging from 25% to 50%. Mature technologies like second-generation ethanol and gasification-based processes tend to fall toward the lower end of this spectrum. This study explores how electrification can enhance the carbon efficiency of biorefinery concepts and investigates its impact on energy, economics and greenhouse gas emissions. Results show that electrification increases carbon efficiency from 28% to 123% for gasification processes, from 28% to 45% for second-generation ethanol, and from 50% to 65% for direct liquefaction processes. Biofuels are produced to a cost range 60–140 EUR/MWh-biofuel, depending on the chosen technology pathway, feedstock and electricity prices. Notably, production in electrified biorefineries proves cost-competitive when compared to pure electrofuel (E-fuels) tracks. Depending on the selected technology pathway and the extent of electrification, a reduction in GHG emissions ranging from 75% to 98% is achievable, particularly when powered by a low-carbon electricity mix.

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  • Kaplan, Alexander F. H.
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Fedina, Tatiana
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development. SWERIM AB, Box 7047, 164 07 Kista, Sweden.
    Brückner, Frank
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development. Fraunhofer IWS, Winterbergstrasse 28, 01277 Dresden, Germany.
    Powell, John
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development. Laser Expertise Ltd., Nottingham, UK.
    Laser induced reduction of iron ore by silicon2023In: Journal of Alloys and Metallurgical Systems, ISSN 2949-9178, Vol. 4, article id 100039Article in journal (Refereed)
    Abstract [en]

    Iron ore powder accompanied by Si-powder as a reducing agent, was melted using a high-power laser beam. During laser melting of the two different powder beds placed next to each other, silicon merged and diffused into the iron ore, forming a ternary melt phase Fe-O-Si of around 30–60–10 at%. High speed imaging of the laser melting process as well as subsequent SEM-analysis of the generated nuggets showed the formation of droplets that merge with the surrounding Si- or ore-powder and form distinct domains. Under certain circumstances, the solidifying nuggets, of the order of 0.5–5 mm in size, generated numerous small domains, up to 25 µm, of high purity iron, 90 + at%, surrounded by a matrix of the above mentioned slag. Many of these Fe-domains were created in the vicinity of regions of high Si-content.

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  • Ögren, Yngve
    et al.
    RISE AB, Box 726 SE-941 28, Piteå, Sweden.
    Sepman, Alexey
    RISE AB, Box 726 SE-941 28, Piteå, Sweden.
    Fooladgar, Ehsan
    RISE AB, Box 726 SE-941 28, Piteå, Sweden.
    Weiland, Fredrik
    RISE AB, Box 726 SE-941 28, Piteå, Sweden.
    Wiinikka, Henrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science. RISE AB, Box 726 SE-941 28, Piteå, Sweden.
    Development and evaluation of a vision driven sensor for estimating fuel feeding rates in combustion and gasification processes2024In: Energy and AI, ISSN 2666-5468, Vol. 15, article id 100316Article in journal (Refereed)
    Abstract [en]

    A machine vision driven sensor for estimating the instantaneous feeding rate of pelletized fuels was developed and tested experimentally in combustion and gasification processes. The feeding rate was determined from images of the pellets sliding on a transfer chute into the reactor. From the images the apparent area and velocity of the pellets were extracted. Area was determined by a segmentation model created using a machine learning framework and velocities by image registration of two subsequent images. The measured weight of the pelletized fuel passed through the feeding system was in good agreement with the weight estimated by the sensor. The observed variations in the fuel feeding correlated with the variations in the gaseous species concentrations measured in the reactor core and in the exhaust. Since the developed sensor measures the ingoing fuel feeding rate prior to the reactor, its signal could therefore help improve process control.

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  • Clegg, Benjamin A.
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Shrestha, Dilesh Raj
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Emami, Nazanin
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Tribo-Mechanical Properties and Bioactivity of Additively Manufactured PAEK Materials for Load Bearing Medical Applications: A Systematic Review2023In: Biotribology, ISSN 2352-5738, Vol. 35-36, article id 100263Article, review/survey (Refereed)
    Abstract [en]

    Additive manufacturing (AM) holds significant potential in transforming medical applications, with a particular focus on polyetheretherketone (PEEK) and its derivatives, collectively known as poly-aryl-ether-ketone (PAEK) materials. Advances in AM precision have paved the way for the successful 3D printing of high-performance thermoplastics like PEEK, offering new prospects in load-bearing medical applications. This systematic review comprehensively assesses recent scientific literature concerning the tribo-mechanical properties and bioactivity of additively manufactured PAEK materials, with a specific emphasis on PEEK, for load-bearing medical uses. Despite substantial research into AM of metallic biomaterials, knowledge gaps persist regarding AM processing parameters, structure-property relationships, biological behaviours, and implantation suitability of PAEKs. This review bridges these gaps by analysing existing literature on the tribo-mechanical properties and bioactivity of additively manufactured PAEK materials, providing valuable insights into their performance in load-bearing medical applications. Key aspects explored include printing conditions, strength limitations, and outcomes of in-vitro and in-vivo evaluations. Through this systematic review, we consolidate current knowledge, delivering essential information for researchers, clinicians, and manufacturers involved in advancing additively manufactured PAEK materials for load-bearing medical applications.

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  • Zhou, Ming
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Bodenmuller, Niklas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Enhanced bio-oil upgrading by sub-microscale dispersed silanol-free ZSM-5 nanosheets and evidence for revealing an unconventional mechanism2023In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 478, article id 147457Article in journal (Refereed)
    Abstract [en]

    Silanol-free ZSM-5 nanosheet with merely 35 nm thickness in the b-axis was synthesized by seeded growth from defect-free 10 nm silicalite-1 in a fluoride medium (denoted as F35). Submicron-scaled stöber sol silica beads were introduced into the gap between nanosheets to serve as a spacer for the prevention of neighboring crystals' close contact with each other, which can improve the heat and mass transportation during the catalytic reactions when compared to the aggregated zeolite crystals. Methanol-to-hydrocarbons (MTH) and model bio-oil upgrading were conducted by using dispersed F35, respectively, and the results were compared to the aggregated ZSM-5. The effluent from bio-oil upgrading through dispersed F35 contains no heavier compound, which was considered as the coke precursor, and significantly reduced amount of unreacted feeding molecule. GC–MS revealed that the coke solution from dispersed F35 contains a considerably reduced (61 %) amount of heavier carbon species. Among them, some species have molecular configurations highly consistent with the zeolite channel structure. The dispersed F35 shows a 33 % longer life in catalytic reactions and a 60 % decreased amount of external thermal cock. An unconventional ‘temperature-determined flexible channel’ mechanism that explains the ‘host–guest’ interactive behavior under catalytic reaction was proposed.

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  • Öhman Aspenes, Kirsten
    et al.
    Luleå University of Technology, Department of Health, Learning and Technology.
    Björkén, Anna
    Luleå University of Technology, Department of Health, Learning and Technology.
    Personers upplevelser av att leva med förmaksflimmer: En litteraturstudie2023Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Bakgrund: Förmaksflimmer är den vanligaste formen av hjärtarytmier och leder till försämrad pumpförmåga och risk för att drabbas av stroke. Personer med förmaksflimmer lever med andra ord med ett långvarigt tillstånd som potentiellt kan leda till allvarlig sjukdom. Syfte: Att beskriva personers upplevelse av att leva med förmaksflimmer. Metod: Systematisk litteraturstudie som inkluderade 15 artiklar som analyserades genom kvalitativ manifest innehållsanalys med induktiv ansats. Resultat: Analysen resulterade i fem kategorier som beskriver personers upplevelser av att leva med FF; Att ha svårt att förstå vad som händer, att känna oro på grund av oförutsägbarheten och att det är en hjärtsjukdom, att behöva stöd och information samt känna förtroende till sjukvården, att känna sig hindrad från att vara aktiv och delta i sociala sammanhang som förut och att successivt acceptera och anpassa sitt liv. Slutsats: För att på bästa sätt tillgodose behov hos personer med FF krävs att sjuksköterskor tillämpar en personcentrerad vård. Detta innebär att ge adekvat och individanpassad information, möta personers emotionella reaktioner samt inkludera närstående i vården.

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  • Hassan Adam Ali, Manasik
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Evolving Community Detection in Dynamic Networks using Nonnegative Tensor Decomposition: An Approach Toward Green Networking2023Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Around 1.8–2.8% of the world’s total greenhouse gas emissions are contributed by the ICT sector, with telecommunications networks accounting for 26.4% of this total ICT share. Given these figures, innovative approaches are essential to tackle the negative impact. This study presents an initial endeavor toward Green Networking by introducing a tensor-based non-negative factorization framework for dynamic community detection in computer networks. We modeled dynamic traffic data from the GEANT network as a 3-way tensor. By employing our Canonical Polyadic Decomposition-based model, we successfully identified three unique clusters, each of which contains multiple nodes that exchange higher traffic levels and show unique time-varying patterns compared to nodes in other clusters. These results, when contrasted with those from a state-of-the-art matrix factorization-based model, showed that our tensor-based approach exhibits greater sensitivity in capturing changes over time among nodes within the identified clusters. This clustering knowledge can guide network reconfigurations to minimize energy consumption across transmission links, promoting more sustainable and energy-efficient network operations

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  • Germundsson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    1D Simulation of Hydraulic Cam Phaser System Utilized in Heavy Duty Vehicles: An Investigation on Attenuation of Phase Oscillations from Cam Torque Disturbances2023Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Cam phasers allow improvements to the efficiency and emissions of internal combustion engines. The usage of hydraulic vane type cam phasers for heavy-duty applications have shown problems with oscillations during testing at \gls{Scania CV}.

    To investigate the root cause of the oscillations a detailed 1-d simulation model has been created. The 1-d simulation model was calibrated and compared against measurements of a cam phaser system mounted on a physical engine. The 1-d simulation model of the cam phaser system was shown to be able to reproduce the oscillatory behavior seen in engine tests. But there are some concerns regarding the model's reliability, due to its dependence on the integration time step.

    It was determined that free air in the phaser chambers is causing the excessive oscillations. The source of the free air present in physical phasers are not yet fully understood, but the movement of the phaser control valve, opening and closing of the phaser chamber vents, in conjunction with motion of the phase oscillations has a significant effect on the phaser's chamber pressure, resulting in reduce pressures. The reduced pressures result in air being sucked in to the phaser, form both the oil control valve vent and external chamber leakages. Another potential sources of free air is dissolved air in the oil supply being released due to low pressures from oil pressure fluctuations.

    A potential solution to increase the stability of the phaser is to reduce the sources of air, by having an oil accumulator at the vent, limiting leakage, having a high and steady oil supply pressure, modifying the oil control valve ports to have a more gradual initial opening area and controlling the oil control valve appropriately. How to implement these implementations and evaluate them are left as future work. Potential improvements to get rid of the 1-d simulation model's dependence on the time step, increasing the model's reliability, are discussed, but not tested.

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  • Fagerström, Erik
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Ljung, Anna-Lena
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Shape and temperature dependence on the directional velocity change in a freezing water droplet2023In: International Journal of Thermofluids, ISSN 2666-2027, Vol. 20, article id 100519Article in journal (Refereed)
    Abstract [en]

    Freezing of water droplets are of interest in areas such as de-icing and anti-icing of wind turbine blades, aircrafts and cars. On part of the ice build-up that has been less studied is the internal flow in water droplets and how it affects the freezing process. In this paper the aim is to investigate how the contact angle, substrate composition and temperature influences the internal flow. Particle Image Velocimetry (PIV) is used to determine the magnitude and direction of the internal flow, with specific emphasis on directional changes. Results show that a larger contact angle will increase the internal velocity, freezing time and time until the directional change. Cooler substrate temperature increase the internal velocity while reducing the freezing time, but the dependence on the time until the directional change is not as pronounced. The result thus indicate differences in the driving forces between freezing time, internal velocity and directional velocity change. Difference due to substrate composition, i.e. mixture of ice and metal versus only metal is furthermore compared.

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  • Almqvist, Andreas
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Burtseva, Evgeniya
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mathematical Science.
    Rajagopal, Kumbakonam
    J. Mike Walker’66 Department of Mechanical Engineering, Texas A&M University, 100 Mechanical Engineering, Office Building, 3123 TAMU, College Station, TX 77843-3123, TX, USA.
    Wall, Peter
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mathematical Science.
    On flow of power-law fluids between adjacent surfaces: Why is it possible to derive a Reynolds-type equation for pressure-driven flow, but not for shear-driven flow?2023In: Applications in Engineering Science, ISSN 2666-4968, Vol. 15, article id 100145Article in journal (Refereed)
    Abstract [en]

    Flows of incompressible Navier–Stokes (Newtonian) fluids between adjacent surfaces are encountered in numerous practical applications, such as seal leakage and bearing lubrication. In seals, the flow is primarily pressure-driven, whereas, in bearings, the dominating driving force is due to shear. The governing Navier–Stokes system of equations can be significantly simplified due to the small distance between the surfaces compared to their size. From the simplified system, it is possible to derive a single lower-dimensional equation, known as the Reynolds equation, which describes the pressure field. Once the pressure field is computed, it can be used to determine the velocity field. This computational algorithm is much simpler to implement than a direct numerical solution of the Navier–Stokes equations and is therefore widely employed by engineers. The primary objective of this article is to investigate the possibility of deriving a type of Reynolds equation also for non-Newtonian fluids, using the balance of linear momentum. By considering power-law fluids we demonstrate that it is not possible for shear-driven flows, whereas it is feasible for pressure-driven flows. Additionally, we demonstrate that in the full 3D model, a normal stress boundary condition at the inlet/outlet implies a Dirichlet condition for the pressure in the Reynolds equation associated with pressure-driven flow. Furthermore, we establish that a Dirichlet condition for the velocity at the inlet/outlet in the 3D model results in a Neumann condition for the pressure in the Reynolds equation.

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  • Waghe, Uday
    et al.
    Department of Civil Engineering, Yeshwantrao Chavan College of Engineering (YCCE), Nagpur 441110, India.
    Agrawal, Dhiraj
    Department of Civil Engineering, Yeshwantrao Chavan College of Engineering (YCCE), Nagpur 441110, India.
    Ansari, Khalid
    Department of Civil Engineering, Yeshwantrao Chavan College of Engineering (YCCE), Nagpur 441110, India.
    Wagh, Monali
    Department of Civil Engineering, Yeshwantrao Chavan College of Engineering (YCCE), Nagpur 441110, India.
    Amran, Mugahed
    Department of Civil Engineering, College of Engineering, Prince Sattam Bin Abdulaziz University, 11942 Alkharj, Saudi Arabia.
    Alsulami, Badr T.
    Department of Civil Engineering, College of Engineering and Islamic Architecture, Umm Al-Qura University, Makkah 24382, Saudi Arabia.
    Maqbool, Hassan M.
    Department of Civil Engineering, Faculty of Engineering, Jazan University, Saudi Arabia.
    Gamil, Yaser
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. Department of Civil Eng., School of Eng., Monash University Malaysia, Jalan Lagoon Selatan, 47500 Sunway, Selangor, Malaysia.
    Enhancing eco-concrete performance through synergistic integration of sugarcane, metakaolin, and crumb rubber: Experimental investigation and response surface optimization2023In: Journal of Engineering Research, ISSN 2307-1877Article in journal (Refereed)
    Abstract [en]

    Sustainable construction has gained paramount importance due to the consideration of the devastating effects of construction activities on the environment. Researchers are exploring innovative approaches to mitigate the carbon footprint and enhance the durability of concrete. In order to regulate the demand and cost of concrete constituents, such as cement and sand, there is a need to invent alternative materials and utilize various industrial and agricultural wastes instead of concrete ingredients, either partially or completely. The experimental investigation and optimization of eco-concrete composites by integrating sugarcane bagasse ash (SCBA), metakaolin (MK), and crumb rubber (CR) are cutting-edge research areas that aim to develop environmentally friendly and high-performance concrete materials. The present research work has attempted to utilize SCBA up to 15% by weight of cement with an increment of 5%, MK as a fractional exchange of cement up to 15% with 5% intervals, and CR was utilized as fractional volumetric substitution of sand from 0% to 15% in concrete. Different sets of combinations were evaluated to identify effects on density, workability, compressive strength, split tensile strength, flexural strength, and microstructural properties. This study has obtained satisfactory results when compared to the control concrete for 10% substitution of cement with MK and 10% substitution of cement with SCBA, along with a 10% replacement of fine aggregate (i.e., sand) with CR. The results were analyzed and optimized using Response Surface Methodology (RSM), which illuminated a strong correlation between experimental findings and RSM models, with an R squared (R2) value of 0.9580. The experimental findings and RSM models showed a significant correlation. The increment in the substitution of sand with CR resulted in a decline in strength, and it can be controlled by adopting different effective pretreatment techniques for CR.

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  • Inqiad, Waleed Bin
    et al.
    Military College of Engineering (MCE), National University of Science and Technology (NUST), Islamabad 44000, Pakistan.
    Siddique, Muhammad Shahid
    Military College of Engineering (MCE), National University of Science and Technology (NUST), Islamabad 44000, Pakistan.
    Alarifi, Saad S.
    Department of Geology and Geophysics, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia.
    Butt, Muhammad Jamal
    COMSATS University Islamabad, Abbottabad Campus, Pakistan.
    Najeh, Taoufik
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Gamil, Yaser
    Department of Civil Engineering, School of Engineering, Monash University Malaysia, Jalan Lagoon Selatan, 47500 Bandar Sunway, Selangor, Malaysia.
    Comparative analysis of various machine learning algorithms to predict 28-day compressive strength of Self-compacting concrete2023In: Heliyon, E-ISSN 2405-8440, Vol. 9, no 11, article id e22036Article in journal (Refereed)
    Abstract [en]

    Construction industry is indirectly the largest source of CO2 emissions in the atmosphere, due to the use of cement in concrete. These emissions can be reduced by using industrial waste materials in place of cement. Self-Compacting Concrete (SCC) is a promising material to enhance the use of industrial wastes in concrete. However, there are very few methods available for accurate prediction of its strength, therefore, reliable models for estimating 28-day Compressive Strength (C–S) of SCC are developed in current study by using three Machine Learning (ML) algorithms including Multi Expression Programming (MEP), Extreme Gradient Boosting (XGB), and Random Forest (RF). The ML models were meticulously developed using a dataset of 231 points collected from internationally published literature considering seven most influential parameters including cement content, quantities of fly ash and silica fume, water content, coarse aggregate, fine aggregate, and superplasticizer dosage to predict C–S. The developed models were evaluated using different statistical errors including Root Mean Square Error (RMSE), Mean Absolute Error (MAE), coefficient of determination (R2) etc. The results showed that the XGB model outperformed the MEP and RF model in terms of accuracy with a correlation R2 = 0.998 compared to 0.923 for MEP and 0.986 for RF. Similar trend was observed for other error metrices. Thus, XGB is the most accurate model for estimating C–S of SCC. However, it is pertinent to mention here that it does not give its output in the form of an empirical equation like MEP model. The construction of these empirical models will help to efficiently estimate C–S of SCC for practical purposes.

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  • Alsaffar, Abdul Kareem K.
    et al.
    Engineering Faculty, University of Babylon, Babylon, Iraq.
    Alquzweeni, Saif S.
    Engineering Faculty, University of Babylon, Babylon, Iraq.
    Al-Ameer, Lubna R.
    Al-Zahraa University for Women, Kerbala, Iraq.
    Ali, Abduljabar H.
    Mechanical Engineering, Al-Mustaqbal University, Al-Hillah, Iraq.
    Mohamed, Ahmed
    School of Civil Engineering and Built Environment, Liverpool John Moores University, Liverpool, L3 3AF, UK.
    Aldaihani, Humoud M.
    Geotechnical and Geoenvironmental Engineering, Implementation Construction Sector, Public Authority for Housing Welfare, Kuwait.
    Reham, A.
    Engineering Faculty, University of Babylon, Babylon, Iraq.
    Al-Ansari, Nadhir
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Al-Hashimi, Osamah
    School of Civil Engineering and Built Environment, Liverpool John Moores University, Liverpool, L3 3AF, UK.
    Shubbar, Ali
    School of Civil Engineering and Built Environment, Liverpool John Moores University, Liverpool, L3 3AF, UK.
    Khan, Mohammad Amir
    Department of Civil Engineering, Galgotias College of Engineering, Greater Noida, 201310, India.
    Hashim, Khalid
    School of Civil Engineering and Built Environment, Liverpool John Moores University, Liverpool, L3 3AF, UK.
    Development of eco-friendly wall insulation layer utilising the wastes of the packing industry2023In: Heliyon, E-ISSN 2405-8440, Vol. 9, no 11, article id e21799Article in journal (Refereed)
    Abstract [en]

    Efficient thermal insulation materials considerably lower power consumption for heating and cooling of buildings, which in turn minimises CO2 emissions and improves indoor comfort conditions. However, the selection of suitable insulation materials is governed by several factors, such as the environmental impact, health impact, cost and durability. Additionally, the disposal of used insulation materials is a major factor that affects the selection of materials because some materials could be very toxic for humans and the environment, such as asbestos-containing materials. Therefore, there is a continuous research effort, in both industry and academia, to develop sustainable and affordable insulation materials. In this context, this work aims at utilising the packing industry wastes (cardboard) to develop an eco-friendly insulation layer, which is a biodegradable material that can be disposed of safely after use. Experimentally, wasted cardboard was collected, cleaned, and soaked in water for 24 h. Then, the wet cardboard was minced and converted into past papers, then cast in square moulds and left in a ventilated oven at 75 °C to dry before de-moulding them. The produced layers were subjected to a wide range of tests, including thermal conductivity, acoustic insulation, infrared imaging and bending resistance. The obtained results showed the developed material has a good thermal and acoustic insulation performance. Thermally, the developed material had the lowest thermal conductivity (λ) (0.039 W/m.K) compared to the studied traditional materials. Additionally, it successfully decreased the noise level from 80 to about 58 dB, which was better than the efficiency of the commercial polyisocyanurate layer. However, the bending strength of the developed material was a major drawback because the material did not resist more than 0.6 MPa compared to 2.0 MPa for the commercial polyisocyanurate and 70.0 MPa for the wood boards. Therefore, it is recommended to investigate the possibility of strengthening the new material by adding fibres or cementitious materials.

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  • Bjuhr, Åsa
    et al.
    Luleå University of Technology, Department of Health, Learning and Technology, Education, Language, and Teaching.
    Palo, Annbritt
    Luleå University of Technology, Department of Health, Learning and Technology, Education, Language, and Teaching.
    Manderstedt, Lena
    Luleå University of Technology, Department of Health, Learning and Technology, Education, Language, and Teaching.
    Polarisation and marginalisation – discourses on Sami as L1 mother tongue instruction in syllabus, and media debate2023In: Intercultural Education, ISSN 1467-5986, E-ISSN 1469-8439Article in journal (Refereed)
    Abstract [en]

    In Sweden, curricula and syllabi for education are politically determined after public consultations. Thus, these educational documents are discursive trade-offs reflecting research, traditions in the educational system, and political ideologies. This study maps the discourses in the syllabus for Sami as L1 mother tongue for preschool class – Year 9, and mother tongue instruction in media debate 2016–2022. It problematises the educational implications of the language ideologies and tensions in the material. While Sami is accorded the status as mother tongue, it does not have the same status as Swedish or even Modern languages. Mother tongue instruction is promoted as the foundation for learning other languages, and multilingualism as an asset for Sweden as a country, and for the individual. The quality of mother tongue instruction is criticised by Sami and other minorities, as well as by those perceiving mother tongue instruction as a threat to assimilation.

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  • Rai, Sanskriti
    et al.
    Department of Biophysics, All India Institute of Medical Sciences, New Delhi, India.
    Bharti, Prahalad Singh
    Department of Biophysics, All India Institute of Medical Sciences, New Delhi, India.
    Singh, Rishabh
    Department of Biophysics, All India Institute of Medical Sciences, New Delhi, India.
    Rastogi, Simran
    Department of Biophysics, All India Institute of Medical Sciences, New Delhi, India.
    Rani, Komal
    Department of Pathology and Laboratory Medicine, All India Institute of Medical Sciences Bibinagar, Hyderabad, India.
    Sharma, Vaibhav
    Luleå University of Technology, Department of Health, Learning and Technology, Nursing and Medical Technology.
    Gorai, Priya Kumari
    Department of Anatomy, All India Institute of Medical Sciences, New Delhi, India.
    Rani, Neerja
    Department of Anatomy, All India Institute of Medical Sciences, New Delhi, India.
    Verma, Bhupendra Kumar
    Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India.
    Reddy, Thota Jagadeshwar
    Analytical Department, CSIR-Indian Institute of Chemical Technology, Hyderabad, India.
    Modi, Gyan Prakash
    Department of Pharmaceutical Engineering and Technology, Indian Institute of Technology BHU, Varanasi, India.
    Inampudi, Krishna Kishore
    Department of Biophysics, All India Institute of Medical Sciences, New Delhi, India.
    Pandey, Hem Chandra
    Department of Transfusion Medicine, All India Institute of Medical Sciences, New Delhi, India.
    Yadav, Sanjay
    Department of Biochemistry, All India Institute of Medical Sciences Raebareli, Uttar Pradesh, India.
    Rajan, Roopa
    Department of Neurology, All India Institute of Medical Sciences, New Delhi, India.
    Nikolajeff, Fredrik
    Luleå University of Technology, Department of Health, Learning and Technology, Nursing and Medical Technology.
    Kumar, Saroj
    Luleå University of Technology, Department of Health, Learning and Technology, Nursing and Medical Technology. Department of Biophysics, All India Institute of Medical Sciences, New Delhi, India; .
    Circulating plasma miR-23b-3p as a biomarker target for idiopathic Parkinson's disease: comparison with small extracellular vesicle miRNA2023In: Frontiers in Neuroscience, ISSN 1662-4548, E-ISSN 1662-453X, Vol. 17, article id 1174951Article in journal (Refereed)
    Abstract [en]

    Background: Parkinson's disease (PD) is an increasingly common neurodegenerative condition, which causes movement dysfunction and a broad range of non-motor symptoms. There is no molecular or biochemical diagnosis test for PD. The miRNAs are a class of small non-coding RNAs and are extensively studied owing to their altered expression in pathological states and facile harvesting and analysis techniques.

    Methods: A total of 48 samples (16 each of PD, aged-matched, and young controls) were recruited. The small extracellular vesicles (sEVs) were isolated and validated using Western blot, transmission electron microscope, and nanoparticle tracking analysis. Small RNA isolation, library preparation, and small RNA sequencing followed by differential expression and targeted prediction of miRNA were performed. The real-time PCR was performed with the targeted miRNA on PD, age-matched, and young healthy control of plasma and plasma-derived sEVs to demonstrate their potential as a diagnostic biomarker.

    Results: In RNA sequencing, we identified 14.89% upregulated (fold change 1.11 to 11.04, p < 0.05) and 16.54% downregulated (fold change −1.04 to −7.28, p < 0.05) miRNAs in PD and controls. Four differentially expressed miRNAs (miR-23b-3p, miR-29a-3p, miR-19b-3p, and miR-150-3p) were selected. The expression of miR-23b-3p was “upregulated” (p = 0.002) in plasma, whereas “downregulated” (p = 0.0284) in plasma-derived sEVs in PD than age-matched controls. The ROC analysis of miR-23b-3p revealed better AUC values in plasma (AUC = 0.8086, p = 0.0029) and plasma-derived sEVs (AUC = 0.7278, p = 0.0483) of PD and age-matched controls.

    Conclusion: We observed an opposite expression profile of miR-23b-3p in PD and age-matched healthy control in plasma and plasma-derived sEV fractions, where the expression of miR-23b-3p is increased in PD plasma while decreased in plasma-derived sEV fractions. We further observed the different miR-23b-3p expression profiles in young and age-matched healthy control.

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  • Poelzer, Gregory A
    Luleå University of Technology, Department of Social Sciences, Technology and Arts, Social Sciences.
    Pursuing Alignment: A Comparison of Public Officials and Citizen Perception of Mine Development2023In: Resources, E-ISSN 2079-9276, Vol. 12, no 11, article id 134Article in journal (Refereed)
    Abstract [en]

    Maintaining legitimacy is a crucial objective for public officials to ensure effectiveness. Without legitimacy, political costs rise as the trust in government decreases and policy implementation is delayed; thus, officials handling resource development are encouraged to improve the acceptability of their processes. Therefore, it is essential for the government to understand the values and expectations of the citizens affected by resource development. Such an understanding assists the government in accomplishing its goals. This paper examines two cases, Norrbotten, Sweden, and Saskatchewan, Canada, both of which have established mining operations and similar regulatory frameworks and, during the commodities boom, experienced increased foreign investment and applications for new mines. While most mining projects in Saskatchewan faced little public opposition, some Norrbotten mines met contestation and protest. This paper utilizes survey data that focus on the perspectives of the residents close to the proposed mining operations, as well as interview data from public officials responsible for mine permitting, to examine the relationship between stakeholder influence and trust in government on the acceptability of mining.

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  • Farnocchia, Davide
    et al.
    Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Pasadena, CA 91109, USA.
    Reddy, Vishnu
    Lunar and Planetary Laboratory, University of Arizona, 1629 E. University Blvd., Tucson, AZ 85721, USA.
    Bauer, James M.
    University of Maryland, 4296 Stadium Dr., Astronomy Dept. Room 1113, College Park, MD 20742, USA.
    Warner, Elizabeth M.
    University of Maryland, 4296 Stadium Dr., Astronomy Dept. Room 1113, College Park, MD 20742, USA.
    Micheli, Marco
    ESA NEO Coordination Centre, Largo Galileo Galilei, 1, I-00044 Frascati (RM), Italy.
    Payne, Matthew J.
    Harvard-Smithsonian Center for Astrophysics, 60 Garden St., MS 51, Cambridge, MA 02138, USA.
    Farnham, Tony
    University of Maryland, 4296 Stadium Dr., Astronomy Dept. Room 1113, College Park, MD 20742, USA.
    Kelley, Michael S.
    Planetary Defense Coordination Office, Planetary Science Division, NASA Headquarters, 300 E St. SW, Washington, DC 20546, USA.
    Alarcon, Miguel R.
    Instituto de Astrofísica de Canarias, C/ Vía Láctea s/n, E-38205 La Laguna, Canarias, Spain; Departamento de Astrofísica, Universidad de La Laguna, E-38206 La Laguna, Canarias, Spain.
    Bacci, Paolo
    GAMP—Osservatorio Astronomico Montagna Pistoiese, Via Pratorsi, I-51028 San Marcello Piteglio (PT), Italy.
    Bacci, Roberto
    GAMP—Osservatorio Astronomico Montagna Pistoiese, Via Pratorsi, I-51028 San Marcello Piteglio (PT), Italy; G. Pascoli Observatory, Via dei Pieri, I-55051 Castelvecchio Pascoli (LU), Italy.
    Bachini, Mauro
    Tavolaia Observatory, Via Tavolaia 4, I-56020 Santa Maria A Monte (PI), Italy; BS-CR Observatory, Via Francesca 329, I-56020 Santa Maria A Monte (PI), Italy.
    Baillie, Kevin
    IMCCE, Paris Observatory, PSL University, CNRS, Sorbonne University, Lille University, 77 av. Denfert-Rochereau, F-75014 Paris, France.
    Baj, Giorgio
    Observatory M57, Via Viggiù 35, I-21050 Saltrio (VA), Italy.
    Bamberger, Daniel
    Northolt Branch Observatories, Dabbs Hill Lane, Northolt, London, UK.
    Barkov, Anatoly P.
    Kuban State University, Stavropolskaya St., 149, Krasnodar 350040, Russia.
    Beck, Stefan
    Altdorf Observatory, Eschelbachstr. 17, D-71088 Holzgerlingen, Germany.
    Betti, Guido
    Observatory Beato Ermanno, Via Sodera 2, I-50023 Impruneta (FI), Italy.
    Biancalani, Enrico
    Nordic Optical Telescope, Rambla José Ana Fernández Pérez 7, E-38711 Breã Baja, Spain; Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark; Leiden Observatory, Leiden University, P.O. Box 9513, NL-2300 RA Leiden, The Netherlands.
    Bolin, Bryce T.
    Division of Physics, Mathematics, and Astronomy, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125, USA; Infrared Processing and Analysis Center, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125, USA; Goddard Space Flight Center, 8800 Greenbelt Rd., Greenbelt, MD 20771, USA.
    Briggs, David
    Hampshire Astronomical Group, Clanfield, Hampshire, UK.
    Buzzi, Luca
    Schiaparelli Astronomical Observatory, Via Orrigoni 4, I-21100 Varese (VA), Italy.
    Cheng, Haowen
    National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Rd., Chaoyang District, Beijing, People's Republic of China.
    Christensen, Eric
    Lunar and Planetary Laboratory, University of Arizona, 1629 E. University Blvd., Tucson, AZ 85721, USA.
    Coffano, Alessandro
    Serafino Zani Observatory, Consortile San Nicola, I-25065 Lumezzane (BS), Italy.
    Conversi, Luca
    ESA NEO Coordination Centre, Largo Galileo Galilei, 1, I-00044 Frascati (RM), Italy.
    Demeautis, Christophe
    PASTIS Observatory, F-04150 Banon, France.
    Denneau, Larry
    Institute for Astronomy, University of Hawaii, 2680 Woodlawn Dr., Honolulu, HI 96822, USA.
    Desmars, Josselin
    IMCCE, Paris Observatory, PSL University, CNRS, Sorbonne University, Lille University, 77 av. Denfert-Rochereau, F-75014 Paris, France; Institut Polytechnique des Sciences Avancées IPSA, 63 boulevard de Brandebourg, F-94200 Ivry-sur-Seine, France.
    Djupvik, Anlaug A.
    Nordic Optical Telescope, Rambla José Ana Fernández Pérez 7, E-38711 Breã Baja, Spain; Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark.
    Elenin, Leonid
    Keldysh Institute of Applied Mathematics, Russian Academy of Sciences, Miusskaya sq. 4, Moscow, 125047, Russia.
    Fini, Paolo
    Observatory Beato Ermanno, Via Sodera 2, I-50023 Impruneta (FI), Italy.
    Felber, Tobias
    Oberfrauendorf Observatory, An der Lockwitz 52, D-01768 Glashütte, Germany.
    Flynn, Randy
    Squirrel Valley Observatory, 3870 River Rd., Columbus, NC 28722, USA.
    Galli, Gianni
    GiaGa Observatory, Via Mozart 4, I-20005 Pogliano Milanese (MI), Italy.
    Granvik, Mikael
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Department of Physics, P.O. Box 64, FI-00014 University of Helsinki, Finland.
    Gray, Bill
    Project Pluto, 168 Ridge Rd., Bowdoinham, ME 04008, USA.
    Gray, Zuri
    Nordic Optical Telescope, Rambla José Ana Fernández Pérez 7, E-38711 Breã Baja, Spain; Armagh Observatory and Planetarium, College Hill, Armagh BT61 9DG, UK; Mullard Space Science Laboratory, Department of Space and Climate Physics, University College London, Holmbury St. Mary, Dorking, Surrey RH5 6NT, UK.
    Grazzini, Luca
    Gruppo Astrofili Montelupo, Via San Vito 60, I-50056 Montelupo Fiorentino (FI), Italy.
    Hasubick, Werner
    Public Observatory Buchloe, Alois-Reiner-Str. 15b, D-86807 Buchloe, Germany.
    Hoffmann, Tobias
    Department of Medical Physics and Acoustics, University of Oldenburg, D-26111 Oldenburg, Germany.
    Holmes, Robert
    Astronomical Research Institute, 7168 NCR 2750E, Ashmore, IL 61912, USA.
    Iozzi, Marco
    H.O.B. Astronomical Observatory, Via Buca dei Tassi 13, I-50050 Capraia Fiorentina (FI), Italy.
    Ivanov, Alexander L.
    Kuban State University, Stavropolskaya St., 149, Krasnodar 350040, Russia.
    Ivanov, Viktor A.
    Kuban State University, Stavropolskaya St., 149, Krasnodar 350040, Russia.
    Ivanova, Natalya V.
    Kuban State University, Stavropolskaya St., 149, Krasnodar 350040, Russia.
    Jacques, Cristóvão
    Southern Observatory for Near Earth Asteroids Research, Oliveira, Brazil.
    Jiang, Hai
    National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Rd., Chaoyang District, Beijing, People's Republic of China.
    Zheng, Jinghui
    Shanghai Astronomical Observatory, Chinese Academy of Science, Shanghai 200030, People's Republic of China.
    Kasikov, Anni
    Nordic Optical Telescope, Rambla José Ana Fernández Pérez 7, E-38711 Breã Baja, Spain; Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark; Tartu Observatory, University of Tartu, Observatooriumi 1, Tõravere, 61602, Estonia.
    Kim, Myung-Jin
    Korea Astronomy and Space Science Institute, 776, Daedeokdae-ro, Yuseong-gu, Daejeon 34055, Republic of Korea.
    Kumar, Balaji
    Golden Ears Observatory, 22938 Vista Ridge Dr., Maple Ridge, BC V4R 2X3, Canada.
    Lee, Hee-Jae
    Korea Astronomy and Space Science Institute, 776, Daedeokdae-ro, Yuseong-gu, Daejeon 34055, Republic of Korea.
    Li, Bin
    Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing, 210023, People's Republic of China; University of Science and Technology of China, Hefei, 230026, People's Republic of China.
    Liu, Jing
    National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Rd., Chaoyang District, Beijing, People's Republic of China.
    Licandro, Javier
    Instituto de Astrofísica de Canarias, C/ Vía Láctea s/n, E-38205 La Laguna, Canarias, Spain; Departamento de Astrofísica, Universidad de La Laguna, E-38206 La Laguna, Canarias, Spain.
    Linder, Tyler
    Astronomical Research Institute, 7168 NCR 2750E, Ashmore, IL 61912, USA.
    Lysenkov, Vadim E.
    Kuban State University, Stavropolskaya St., 149, Krasnodar 350040, Russia.
    Maestripieri, Martina
    GAMP—Osservatorio Astronomico Montagna Pistoiese, Via Pratorsi, I-51028 San Marcello Piteglio (PT), Italy.
    Mantero, Andrea
    Bernezzo Observatory, Via Maggiori 28, I-12010 Bernezzo (CN), Italy.
    Marinello, Vladimiro
    Serafino Zani Observatory, Consortile San Nicola, I-25065 Lumezzane (BS), Italy.
    McCormick, Jennie
    Farm Cove Observatory, 2/24 Rapallo Place, Farm Cove, Auckland 2010, New Zealand.
    Moon, Darrel
    Killer Rocks Observatory, HC 65 Box 2, Pie Town, NM 87827, USA.
    Nastasi, Alessandro
    GAL Hassin—Centro Internazionale per le Scienze Astronomiche, Via della Fontana Mitri, I-90010 Isnello (PA), Italy.
    Neill, James D.
    Division of Physics, Mathematics, and Astronomy, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125, USA.
    Neue, Guenther
    Wickede Observatory, Stemmering 5, D-44319 Dortmund, Germany.
    Novichonok, Artem O.
    Petrozavodsk State University, Lenin St., 33, 185910, Petrozavodsk, Republic of Karelia, Russia.
    Ocaña, Francisco
    ESA NEO Coordination Centre, Largo Galileo Galilei, 1, I-00044 Frascati (RM), Italy.
    Pizzetti, Gianpaolo
    Serafino Zani Observatory, Consortile San Nicola, I-25065 Lumezzane (BS), Italy.
    Pomazan, Anton
    Shanghai Astronomical Observatory, Chinese Academy of Science, Shanghai 200030, People's Republic of China.
    Purdum, Josiah N.
    Division of Physics, Mathematics, and Astronomy, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125, USA.
    Ratinaud, Christophe
    Landehen Observatory (Z43), 14 allée des Ajoncs d'Or F-22400 LANDEHEN, France.
    Roh, Dong-Goo
    Korea Astronomy and Space Science Institute, 776, Daedeokdae-ro, Yuseong-gu, Daejeon 34055, Republic of Korea.
    Romanov, Filipp D.
    Amateur astronomer, Russia; Remote observer of the Liverpool Telescope, La Palma, Spain; iTelescope.Net observatories: New Mexico Skies, Mayhill, NM, USA; Siding Spring Observatory, Australia.
    Ruocco, Nello
    Osservatorio Astronomico Nastro Verde, Via Nastro Verde, I-80067 Sorrento (NA), Italy.
    Santana-Ros, Toni
    Instituto de Física Aplicada a las Ciencias y las Tecnologías, Universidad de Alicante, San Vicente del Raspeig, E-03080, Alicante, Spain; Institut de Ciències del Cosmos (ICCUB), Universitat de Barcelona (IEEC-UB), Carrer de Martí i Franquès, 1, E-08028 Barcelona, Spain.
    Scarmato, Toni
    Toni Scarmato's Observatory, Via U. Foscolo 3, I-89817 San Costantino di Briatico (VV), Italy.
    Schmalz, Anastasia
    Keldysh Institute of Applied Mathematics, Russian Academy of Sciences, Miusskaya sq. 4, Moscow, 125047, Russia.
    Schmalz, Sergei
    Keldysh Institute of Applied Mathematics, Russian Academy of Sciences, Miusskaya sq. 4, Moscow, 125047, Russia.
    Serra-Ricart, Miquel
    Instituto de Astrofísica de Canarias, C/ Vía Láctea s/n, E-38205 La Laguna, Canarias, Spain; Departamento de Astrofísica, Universidad de La Laguna, E-38206 La Laguna, Canarias, Spain.
    Sherrod, Clay
    Arkansas Sky Observatories, ASO Scientific Studies Inc., 73 Tanyard Springs Rd., Petit Jean Mountain, AR 72110, USA.
    Sioulas, Nick
    NOAK Observatory, Delfon 2 Stavraki, Ioannina, 45500, Greece.
    Soffiantini, Andrea
    Serafino Zani Observatory, Consortile San Nicola, I-25065 Lumezzane (BS), Italy.
    Succi, Giacomo
    Tavolaia Observatory, Via Tavolaia 4, I-56020 Santa Maria A Monte (PI), Italy; BS-CR Observatory, Via Francesca 329, I-56020 Santa Maria A Monte (PI), Italy.
    Tholen, David J.
    Institute for Astronomy, University of Hawaii, 2680 Woodlawn Dr., Honolulu, HI 96822, USA.
    Thomsen, Jeppe S.
    Nordic Optical Telescope, Rambla José Ana Fernández Pérez 7, E-38711 Breã Baja, Spain; Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark; Dipartimento di Fisica e Astronomia, Università di Bologna, Via Zamboni 33, I-40126 Bologna, Italia.
    Thuillot, William
    IMCCE, Paris Observatory, PSL University, CNRS, Sorbonne University, Lille University, 77 av. Denfert-Rochereau, F-75014 Paris, France.
    Wainscoat, Richard
    Institute for Astronomy, University of Hawaii, 2680 Woodlawn Dr., Honolulu, HI 96822, USA.
    Wells, Guy
    Northolt Branch Observatories, Dabbs Hill Lane, Northolt, London, UK.
    Weryk, Robert
    Physics and Astronomy, The University of Western Ontario, 1151 Richmond St., London, ON N6A 3K7, Canada.
    Yakovenko, Nikolai A.
    Kuban State University, Stavropolskaya St., 149, Krasnodar 350040, Russia.
    Yim, Hong-Suh
    Korea Astronomy and Space Science Institute, 776, Daedeokdae-ro, Yuseong-gu, Daejeon 34055, Republic of Korea.
    Zhai, Chengxing
    Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Pasadena, CA 91109, USA.
    The Second International Asteroid Warning Network Timing Campaign: 2005 LW32023In: The Planetary Science Journal, E-ISSN 2632-3338, Vol. 4, no 11, article id 203Article in journal (Refereed)
    Abstract [en]

    The Earth close approach of near-Earth asteroid 2005 LW3 on 2022 November 23 represented a good opportunity for a second observing campaign to test the timing accuracy of astrometric observation. With 82 participating stations, the International Asteroid Warning Network collected 1046 observations of 2005 LW3 around the time of the close approach. Compared to the previous timing campaign targeting 2019 XS, some individual observers were able to significantly improve the accuracy of their reported observation times. In particular, U.S. surveys achieved good timing performance. However, no broad, systematic improvement was achieved compared to the previous campaign, with an overall negative bias persisting among the different observers. The calibration of observing times and the mitigation of timing errors should be important future considerations for observers and orbit computers, respectively.

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  • Scharf, Alexander
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Popescu, Carmen-Mihaela
    Petru Poni Institute of Macromolecular Chemistry, 41A Grigore Ghica Voda Alley, 700487 Iasi, Romania.
    Dernegård, Henric
    Holmen AB, Strandvägen 1, SE-11451 Stockholm, Sweden.
    Oja, Johan
    Norra Timber, Skeppargatan 1, SE-90403 Umeå, Sweden.
    Ormondroyd, Graham
    Biocomposites Centre, Bangor University, Deiniol Road, Bangor LL57 2UW, UK.
    Medved, Sergej
    Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000 Ljubljana, Slovenia.
    Sandberg, Dick
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Jones, Dennis
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Particleboards Bonded by an Imidazole-Based Adhesive System2023In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 16, no 22, article id 7201Article in journal (Refereed)
    Abstract [en]

    Particleboards with different combinations of the adhesive material imidazole, citric acid, and sorbitol were produced. Softwood sawdust from a Swedish sawmill was mixed with an aqueous solution of the chemicals and then dried to 0% moisture content prior to pressing. The boards were pressed to a target density of 700 kg m−3 at either 200 °C or 220 °C for 10 min. The hygroscopic and mechanical properties of the boards were clearly better at 220 °C than 200 °C for all used chemical combinations. A combination of imidazole (14.4 wt%) and citric acid (11.3 wt%) led to the best results, where the thickness swelling after 24 h of water immersion was 6.3% and the internal bonding strength was 0.57 MPa. The modulus of rupture and modulus of elasticity were 3.3 MPa and 1.1 GPa, respectively. Cyclic accelerated weathering showed exceptional stability with a thickness change after boiling and drying of only 2.1% compared to the initial dry thickness. This study indicates that the presence of imidazole leads to greatly improved hygroscopic properties and good internal bonding strength when used in particleboards.

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  • Sperlich, Billy
    et al.
    Integrative and Experimental Training Science, Institute of Sport Sciences, University of Würzburg, Würzburg, Germany.
    Matzka, Manuel
    Integrative and Experimental Training Science, Institute of Sport Sciences, University of Würzburg, Würzburg, Germany.
    Holmberg, Hans-Christer
    Luleå University of Technology, Department of Health, Learning and Technology, Health, Medicine and Rehabilitation. Department of Physiology and Pharmacology, Biomedicum C5, Karolinska Institutet, Stockholm, Sweden.
    The proportional distribution of training by elite endurance athletes at different intensities during different phases of the season2023In: Frontiers in Sports and Active Living, E-ISSN 2624-9367, Vol. 5, article id 1258585Article, review/survey (Refereed)
    Abstract [en]

    The present review examines retrospective analyses of training intensity distribution (TID), i.e., the proportion of training at moderate (Zone 1, Z1), heavy (Z2) and severe (Z3) intensity by elite-to-world-class endurance athletes during different phases of the season. In addition, we discuss potential implications of our findings for research in this field, as well as for training by these athletes. Altogether, we included 175 TIDs, of which 120 quantified exercise intensity on the basis of heart rate and measured time-in-zone or employed variations of the session goal approach, with demarcation of zones of exercise intensity based on physiological parameters. Notably, 49% of the TIDs were single-case studies, predominantly concerning cross-country skiing and/or the biathlon. Eighty-nine TIDs were pyramidal (Z1 > Z2 > Z3), 65 polarized (Z1 > Z3 > Z2) and 8 “threshold” (Z2 > Z1 = Z3). However, these relative numbers varied between sports and the particular phases of the season. In 91% (n = 160) of the TIDs >60% of the endurance exercise was of low intensity. Regardless of the approach to quantification or phase of the season, cyclists and swimmers were found to perform a lower proportion of exercise in Z1 (<72%) and higher proportion in Z2 (>16%) than athletes involved in the triathlon, speed skating, rowing, running, cross-country skiing or biathlon (>80% in Z1 and <12% in Z2 in all these cases). For most of the athletes their proportion of heavy-to-severe exercise was higher during the period of competition than during the preparatory phase, although with considerable variability between sports. In conclusion, the existing literature in this area does not allow general conclusions to be drawn. The methods utilized for quantification vary widely and, moreover, contextual information concerning the mode of exercise, environmental conditions, and biomechanical aspects of the exercise is often lacking. Therefore, we recommend a more comprehensive approach in connection with future investigations on the TIDs of athletes involved in different endurance sports.

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  • Li, Yangshuo
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Li, Fangfang
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Laaksonen, Aatto
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science. Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, 106 91 Stockholm, Sweden; Centre of Advanced Research in Bionanoconjugates and Biopolymers, Petru Poni Institute of Macromolecular Chemistry, Aleea Grigore Ghica-Voda, 41A, 700487 Iasi, Romania; State Key Laboratory of Materials-Oriented and Chemical Engineering, Nanjing Tech University, Nanjing, P. R. China; University of Cagliari, Department of Chemical and Geological Sciences, Campus Monserrato, SS 554 bivio per Sestu, Monserrato, Italy.
    Wang, Chuan
    Metallurgy Department, Swerim AB, Luleå, Sweden .
    Cobden, Paul
    Metallurgy Department, Swerim AB, Luleå, Sweden .
    Boden, Per
    SMA Mineral AB, Filipstad, Sweden .
    Liu, Yanrong
    CAS Key Laboratory of Green Process and Engineering, Beijing Key Laboratory of Ionic Liquids Clean Process, State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China.
    Zhang, Xiangping
    CAS Key Laboratory of Green Process and Engineering, Beijing Key Laboratory of Ionic Liquids Clean Process, State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China.
    Ji, Xiaoyan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Electrochemical CO2 reduction with ionic liquids: review and evaluation2023In: Industrial Chemistry & Materials, ISSN 2755-2608, Vol. 1, no 3, p. 410-430Article, review/survey (Refereed)
    Abstract [en]

    The increasing CO2 emission, as the chief culprit causing numerous environmental problems, could be addressed by the electrochemical CO2 reduction (CO2R) to the added-value carbon-based chemicals. Ionic liquids (ILs) as electrolytes and co-catalysts have been widely studied to promote CO2R owing to their unique advantages. Among the potential products of CO2R, those only containing one carbon atom, named C1 products, including CO, CH3OH, CH4, and syngas, are easier to achieve than others. In this study, we first summarized the research status on CO2R to these C1 products, and then, the state-of-the-art experimental results were used to evaluate the economic potential and environmental impact. Considering the rapid development in CO2R, future scenarios with better CO2R performances were reasonably assumed to predict the future business for each product. Among the studied C1 products, the research focuses on CO, where satisfactory results have been achieved. The evaluation shows that producing CO via CO2R is the only profitable route at present. CH3OH and syngas of H2/CO (1 : 1) as the targeted products can become profitable in the foreseen future. In addition, the life cycle assessment (LCA) was used to evaluate the environmental impact, showing that CO2R to CH4 is the most environmentally friendly pathway, followed by the syngas of H2/CO (2 : 1) and CO, and the further improvement of the CO2R performance can make all the studied C1 products more environmentally friendly. Overall, CO is the most promising product from both economic and environmental impact aspects.

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  • Mohammed, Fahim
    Luleå University of Technology, Department of Social Sciences, Technology and Arts.
    Exploring the Influence of Cognitive Social Capital on the Attractiveness of Innovation Hubs: An Analysis of Industry Attraction and Network Development in Southern Sweden2023Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This study provides valuable insights into the factors making an innovation hub attractive to potential tenants, with a specific emphasis on the role of cognitive social capital (CSC). Drawing on semi-structured interviews with industry professionals, the research uses thematic analysis to parse out key themes and sub-themes. It uncovers the multi-layered value offered by innovation hubs, highlighting the significance of not only tangible elements like physical infrastructure, but also intangible aspects such as networking, collaboration, knowledge, and learning opportunities. Moreover, the strategic role of an innovation hub in helping businesses meet their objectives is accentuated. The research delves deeper into CSC, revealing the intricate interplay of shared values and understanding, trust, and recognition in enriching the attractiveness of innovation hubs. Furthermore, the study suggests potential avenues for additional services, underscoring the desire for consultancy expertise and wellness facilities. The findings underscore the critical role innovation hubs play in fostering entrepreneurship and the potential they hold in contributing to economic development when they focus on building a supportive and interconnected community. The research not only illuminates the importance of CSC in the context of innovation hubs but also indicates future areas of investigation for scholars and practitioners alike.

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  • Gradén, Samuel
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    Server-side factor graph optimization for on-manifold pre-integration in IoT sensors2023Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    State and specifically location estimation is a core concept in automation and is a well-researched field. One such estimation technique is Moving Horizon Estimation (MHE). In this thesis, the MHE variant single-shooting estimation will estimate the location and velocity of a moving object. The moving object is equipped with an  Inertial Measuring Unit (IMU)  measuring acceleration and angular velocity. This thesis will explore pre-integrating the IMU measurement on the device attached to the moving object and using them in another device running the MHE. The acceleration and angular velocity measurements are measured in the local frame of reference of the moving object, rotating the measurement to a global frame of reference requires a known rotation of the tracked object, finding this rotation is also a task in this thesis. This thesis found the presented theory ill-equipped to estimate the object's state without an angle measurement, this thesis assumed any such measurement is made from a magnetometer but the solution presented is not biased towards any other method of measuring angles. With the addition of an angel measurement, the estimation performs at a decimeter-level precision for location.

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  • Axelsson, Susanne
    et al.
    Department of Psychology, Umeå University, Umeå, Sweden.
    Kihlberg, Sara
    Department of Psychology, Umeå University, Umeå, Sweden.
    Davis, Paul
    Department of Psychology, Umeå University, Umeå, Sweden.
    Nyström, Markus B. T.
    Luleå University of Technology, Department of Health, Learning and Technology, Health, Medicine and Rehabilitation.
    Psychotherapy students' experiences of supervisee-centred supervision based on deliberate practice, feedback-informed treatment and self-compassion2023In: Counselling and Psychotherapy Research, ISSN 1473-3145, E-ISSN 1746-1405Article in journal (Refereed)
    Abstract [en]

    Objective: There are few methods that focus on therapists' experiences of supervision. To facilitate the development of psychologist students, a supervisee-centred supervision, based on deliberate practice, feedback informed treatment and self-compassion, was introduced.

    Methods: This study examines six supervisees’ experiences of a supervisee-centred supervision. A semi- structured interview was used for the collection of the data, which identified two main themes: Learning and Development and five associated sub-themes: structure and purposesfulness, prerequisites, experience-based learning, therapeutic skills and personal development.

    Conclusion: The experience- and feedback-based approach was perceived as efficient, structured and goal oriented. This created high-focused activity and participation, a strong group dynamic and a good alliance with the supervisors, providing a good climate for learning and development. Focusing on performance and feedback was perceived as a potential obstacle that could create stress and anxiety.

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  • Söderholm, Patrik
    et al.
    Luleå University of Technology, Department of Social Sciences, Technology and Arts, Social Sciences.
    Ericsson, Magnus
    Luleå University of Technology, Department of Social Sciences, Technology and Arts, Social Sciences. RMG Consulting, Stockholm, Sweden.
    Hellman, Frida
    Luleå University of Technology, Department of Social Sciences, Technology and Arts, Social Sciences.
    The perils of ranking mining countries and regions: a critical look at the annual survey of the Fraser Institute2023In: Mineral Economics, ISSN 2191-2203, E-ISSN 2191-2211Article in journal (Refereed)
    Abstract [en]

    The attractiveness of mineral investments across countries and regions worldwide can be judged through various measures, each with its strengths and weaknesses. The purpose of this paper is to scrutinize the Fraser Institute’s ranking of mining jurisdictions, which builds on eliciting the perceptions of industry representatives around the world through an annual survey. The analysis takes stock in the growing scholarship on country performance indicators and concludes that due to the low response rate and the lack of clear definitions of some of the underlying concepts (e.g., political stability), there are reasons to question both the reliability and the validity of this survey. There could also exist incentives among exploration companies to “game” the rankings. For these reasons, the ranking outcomes do not constitute a meaningful scorecard that countries can employ to improve their mining-related policies. However, despite these deficiencies, the Fraser Institute’s survey often enjoys relatively uncritical media attention. It even sets in motion a political “rankings game” in which the mining companies, governments, and other organized groups choose to participate. There is an urgent need for a more reliable and unbiased survey approach, including the consideration of alternative—complementing—measures for assessing investment attractiveness in the mining industry.

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  • Arfi, Nadir
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    Deployment planning of UAV Base Stations using Multi Objective Evolutionary Algorithms (MOEA)2023Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This research study focuses on solving the deployment planning problem for UAV-BSs using Multi-Objective Evolutionary Algorithms (MOEAs). The main research objectives encompass gridbased modelling of the target area, investigating evolution parameters, and evaluating algorithm performance in diverse deployment scenarios. Cost, coverage, and interference are considered as objectives along with specific constraints to generate optimal deployment plans. The solution incorporates objective decision support for selecting the best solution among the Pareto front. The research also accounts for parameter initialization and UAV network heterogeneity. Through comprehensive evaluations, the proposed solution demonstrates computational efficiency and the ability to generate satisfactory deployment plans. The study recommends using NonDominated Sorting Genetic Algorithm-II (NSGA-II) for optimal performance. The research also incorporates a fitness approximation technique to reduce computational time while maintaining solution quality. The findings provide valuable insights and recommendations for efficient and balanced deployment planning. However, the research acknowledges limitations and suggests future enhancements. Overall, this research contributes to the field by establishing a foundation for robust and practical deployment plans, guiding future advancements. Future research should focus on addressing identified limitations to enhance applicability and effectiveness in real-world deployment scenarios.

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  • Nordin, Anna
    et al.
    Karlstad University, Department of Health Science, Faculty of Health, Science and Technology, Karlstad, Sweden.
    Engström, Åsa
    Luleå University of Technology, Department of Health, Learning and Technology, Nursing and Medical Technology.
    Andersson, Maria
    Swedish Red Cross University, SE-141 21 Huddinge, Sweden.
    Fredholm, Angelica
    Karlstad University, Department of Health Science, Faculty of Health, Science and Technology, Karlstad, Sweden.
    Intensive Care Managers' Experiences of the COVID-19 Pandemic: A Dramatic Change of the Intensive Care Landscape2023In: Journal of Nursing Management, ISSN 0966-0429, E-ISSN 1365-2834, article id 3052994Article in journal (Refereed)
    Abstract [en]

    Aim. To describe intensive care managers&apos; experiences of premises and resources of care in intensive care units during the COVID-19 pandemic.

    Background. Intensive care units (ICUs) were enormously pressured during the COVID-19 pandemic from many ill patients, requiring advanced care. Hospital and community volunteers increased staff strength. Obligatorily, recruitments were also conducted using transfer of staff from different hospital departments. However, there is little knowledge about intensive care managers&apos; (ICMs) experiences of leadership during the COVID-19 pandemic.

    Methods. A qualitative descriptive study was conducted from March to April 2022. Semistructured interviews were held with 12 ICMs who were purposively sampled from the ICU in ten Swedish hospitals. Data were analysed using qualitative content analysis.

    Results. Two themes emerged: a dramatic change of the intensive care landscape and we could handle more than we thought, but at a steep price. Participants described that the ICUs had to perform extraordinary changes at a very fast pace, which initially created a sense of cohesion. Training and introduction to war-like conditions associated with uncertainty meant that ICMs had to support ICU staff in prioritising interventions. Participants described how ICUs stood strong against a pandemic, but stress, worries, and anxiety took a heavy toll on ICU staff and ICMs. The pandemic eroded the resilience in ICUs. Participants described a deterioration in health and said that sick leaves and resignations occurred.

    Conclusion. Our findings show ICMs&apos; experiences as a field of tension between resources and demands, whereby the changes created a heavy burden that left intensive care weakened.

    Implications for Nursing Management. Findings emphasised the importance of creating working conditions using human resources and materials in order to rebuild resilience in intensive care with the ability to conduct safe patient care.

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  • Djurstedt Niska, Natalie
    et al.
    Luleå University of Technology, Department of Health, Learning and Technology.
    Dahlquist, Maria
    Luleå University of Technology, Department of Health, Learning and Technology.
    Sjuksköterskors upplevelse av etiska utmaningar vid palliativ vård på vårdavdelning: en litteraturstudie2023Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Bakgrund: Sjuksköterskor som arbetar på sjukhusens vårdavdelningar kommer ofta i kontakt med palliativ vård och vård i livets slutskede. Sjuksköterskors perspektiv på hur det är att vårda palliativa patienter på en kurativ avdelning och de etiska dilemman de står inför, kan ge värdefulla insikter i hur vård i livets slutskede kan förbättras. Syfte: Att beskriva sjuksköterskor upplevelse av etiska utmaningar vid palliativ vård på en vårdavdelning. Metod: Systematisk litteratursökning genomfördes i databaserna CINAHL och PubMed. Sökningen resulterade i 15 vetenskapliga artiklar. Analysen av artiklarna gjordes med en kvalitativ induktiv innehållsanalys med en manifest ansats. Resultat: Analysen resulterade i sex slutkategorier, vilka var: Att känna sig maktlös, Att patientens rättigheter inte respekteras, Att känna sig otillräcklig i sin yrkesroll, Att inte kunna ge patienten en värdig död, Att hamna i konfliktsituationer och Att uppleva skuld- och skamkänslor. Slutsats: Resultatet visar att etiska utmaningar som uppstår inom palliativ vård på vårdavdelningar ofta beror på bristande teamsamverkan och kommunikationsbrister inom teamet. Det visar även att sjuksköterskor har låg tro på sin kunskap samt kompetens. Sjuksköterskor behöver bryta hierarkier, motverka maktpositioner och stärka det interprofessionella samarbetet inom teamet. Sjuksköterskor har ett lagstadgat ansvar för att omvårdnaden utförs på ett etiskt korrekt sätt. Det krävs att varje sjuksköterska vågar ta det ansvaret, samt vågar leda och stärka kollegor och varandra i det etiska arbetet. I framtida forskning vore det intressant att undersöka vad som krävs för att stärka sjuksköterskors självkänsla och ledarskap i mötet med etiska utmaningar.

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  • Wang, Nan
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Wang, Dong
    Sinopec Nanjing Chemical Research Institute, Nanjing, China.
    Krook-Riekkola, Anna
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Ji, Xiaoyan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    MEA-based CO2 capture: a study focuses on MEA concentrations and process parameters2023In: Frontiers in Energy Research, E-ISSN 2296-598X, Vol. 11, article id 1230743Article in journal (Refereed)
    Abstract [en]

    CO2 capture using monoethanolamine (MEA) is one of the important decarbonization options and often considered as a benchmark, while the optimal MEA contraction and systematic process study are still lacking. In this work, firstly, the MEA concentrations between 15 and 30 wt% were studied from both process simulations with Aspen Plus and experimental measurements in the pilot-scale. 20 wt% MEA was identified as the preferable solution. Subsequently, a systematic analysis was conducted for CO2 capture using 20 wt% MEA with/without CO2 compression to study how various parameters, including gas flow rate, CO2 concentration, and CO2 removal rate, affected the energy demand and techno-economic performances quantitatively. The influence of each parameter on both energy demand and cost showed an obvious non-linear relationship, evidencing the importance of systematic analysis for further study on decarbonization. The evaluation indicated that the regeneration heat required the largest portion of energy demand. The economic analysis showed that the capital cost was more sensitive to the selected parameters than the operational cost, while the operational cost created a major change in the overall cost. In addition, the gas flow rate and CO2 concentration were the main parameters affecting the cost, rather than the CO2 removal rate. Finally, it was suggested that, for a new plant, CO2 capture showed the minimum investment cost per ton CO2 when operating the plant on a large scale, high CO2 concentration, and high CO2 removal rate; for an existing plant, the capture preferred to run with the high CO2 removal rate.

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  • Siddanathi, Likitha Sai
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Åkerstedt, Hans O.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Wiinikka, Henrik
    RISE AB, SE-941 38 Piteå, Sweden.
    Sepman, Alexey
    RISE AB, SE-941 38 Piteå, Sweden.
    Computational Modeling of a Plasma Torch Using Single-Fluid and Two-Fluid Modeling Approaches2023Conference paper (Refereed)
    Abstract [en]

    Plasma, a complex fluid consisting of electrons, ions, neutrals, and excited species, exhibits both fluid-like behavior and electrical conductivity due to the presence of charge carriers. Consequently, computational modeling of plasma requires the integration of fluid and electrical models. This research paper presents a study on the steady-state computational modeling of a plasma torch with a 2D axisymmetric geometry using single-fluid and two-fluid modeling approaches in the COMSOL Multiphysics® software. The single-fluid modeling (SFM) approach combines the individual equations governing the behavior of different particles into a unified equation. Specifically, the SFM approach utilized in this study focuses on a fully ionized plasma and employs the Magnetohydrodynamic equations whose adaptation is equilibrium discharge interface (EDI) model available in COMSOL Multiphysics®. The EDI model solves the magnetohydrodynamic (MHD) equations, encompassing electric and magnetic fields, heat transfer in solids and fluids, and laminar models. By employing this approach, the researchers simulated and analyzed the behavior of the plasma torch. In contrast, the two-fluid modeling (TFM) approach separates the fluid equations for electrons and ions, considering a weakly ionized plasma. The TFM model is developed by deriving fluid equations based on kinetic theory for neutrals, ions, and electrons. These equations are then implemented in COMSOL Multiphysics®, utilizing models for the transport of diluted species, laminar flow, heat transfer in solids and fluids, and electric and magnetic fields. By adopting the TFM approach, the researchers aimed to gain insights into the behavior of the plasma torch. Throughout the study, various properties such as temperature, velocity, current density, and particle concentrations are analyzed within the plasma torch. Results obtained from both the single-fluid and two-fluid modeling approaches are compared and evaluated. This comparative analysis allows the researchers to highlight the advantages and challenges associated with each modeling approach. In conclusion, this study contributes to understanding plasma behavior by employing computational modeling techniques. The research presents and compares the outcomes of single-fluid and two-fluid modeling approaches applied to a plasma torch. By examining the advantages and challenges of each approach, the study offers valuable insights for future plasma modeling endeavors.

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  • Aaröe, Olivia
    et al.
    Luleå University of Technology, Department of Health, Learning and Technology.
    Ullenius Ekengren, Fanny
    Luleå University of Technology, Department of Health, Learning and Technology.
    Personers upplevelser av att leva med lungfibros: En litteraturstudie2023Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Bakgrund: Lungfibros är en kronisk respiratorisk sjukdom som kännetecknas av nedsatt lungfunktion och andningssvårigheter. Det finns otillräckliga resurser i form av stöd för personen som drabbats av lungfibros och sjukdomen missförstås av hälso-och sjukvårdspersonal och samhället. Behandlingen är bristfällig och fokuserar i dagsläget på att förebygga, behandla och lindra symtom för att öka livskvaliteten för personen som är drabbad. Det finns utmaningar med vård som enbart fokuserar på symtomlindring och det finns behov av ytterligare insatser för att uppnå en förbättrad livskvalitet hos den enskilda personen med lungfibros. Syfte: Att beskriva personers upplevelser av att leva med lungfibros. Metod: Litteraturstudie med induktiv ansats där tio vetenskapliga artiklar har analyserats med kvalitativ manifest innehållsanalys. Resultat: Analysen resulterade i fem slutkategorier som beskriver personers upplevelser av att leva med lungfibros: en turbulent resa från symtom till diagnos, att känna en inre och yttre påverkan, en förändring och påverkan i det dagliga livet, att ha behov av stöd och information, och att ha funderingar inför en oviss framtid. Slutsats: För personer som lever med lungfibros och deras närstående är stöd, information och copingstrategier avgörande i det dagliga livet. Sjuksköterskan har en viktig roll gällande kommunikation och den bör vara personcentrerad och anpassad till personens behov och takt. Samtal om livets slutskede är nödvändigt för personer med lungfibros, men brister ofta i vård och omvårdnad av denna patientgrupp. 

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  • de Koning, Enrico
    et al.
    Cardiology Department, Leiden University Medical Center, Leiden, Netherlands.
    van der Haas, Yvette
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Saguna, Saguna
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Stoop, Esmee
    Clinical AI and Research lab, Leiden University Medical Center, Leiden, Netherlands.
    Bosch, Jan
    Research and Development, Regional Ambulance Service Hollands-Midden, Leiden, Netherlands.
    Beeres, Saskia
    Cardiology Department, Leiden University Medical Center, Leiden, Netherlands.
    Schalij, Martin
    Cardiology Department, Leiden University Medical Center, Leiden, Netherlands.
    Boogers, Mark
    Cardiology Department, Leiden University Medical Center, Leiden, Netherlands.
    AI Algorithm to Predict Acute Coronary Syndrome in Prehospital Cardiac Care: Retrospective Cohort Study2023In: JMIR Cardio, E-ISSN 2561-1011, Vol. 7, no 1, article id e51375Article in journal (Refereed)
    Abstract [en]

    Background: Overcrowding of hospitals and emergency departments (EDs) is a growing problem. However, not all ED consultations are necessary. For example, 80% of patients in the ED with chest pain do not have an acute coronary syndrome (ACS). Artificial intelligence (AI) is useful in analyzing (medical) data, and might aid health care workers in prehospital clinical decision-making before patients are presented to the hospital.

    Objective: The aim of this study was to develop an AI model which would be able to predict ACS before patients visit the ED. The model retrospectively analyzed prehospital data acquired by emergency medical services' nurse paramedics.

    Methods: Patients presenting to the emergency medical services with symptoms suggestive of ACS between September 2018 and September 2020 were included. An AI model using a supervised text classification algorithm was developed to analyze data. Data were analyzed for all 7458 patients (mean 68, SD 15 years, 54% men). Specificity, sensitivity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for control and intervention groups. At first, a machine learning (ML) algorithm (or model) was chosen; afterward, the features needed were selected and then the model was tested and improved using iterative evaluation and in a further step through hyperparameter tuning. Finally, a method was selected to explain the final AI model.

    Results: The AI model had a specificity of 11% and a sensitivity of 99.5% whereas usual care had a specificity of 1% and a sensitivity of 99.5%. The PPV of the AI model was 15% and the NPV was 99%. The PPV of usual care was 13% and the NPV was 94%.

    Conclusions: The AI model was able to predict ACS based on retrospective data from the prehospital setting. It led to an increase in specificity (from 1% to 11%) and NPV (from 94% to 99%) when compared to usual care, with a similar sensitivity. Due to the retrospective nature of this study and the singular focus on ACS it should be seen as a proof-of-concept. Other (possibly life-threatening) diagnoses were not analyzed. Future prospective validation is necessary before implementation.

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  • Perham, Nick
    et al.
    Department of Applied Psychology, Cardiff Metropolitan University, Cardiff, UK.
    Begum, Fahena
    Department of Applied Psychology, Cardiff Metropolitan University, Cardiff, UK.
    Marsh, John Everett
    Luleå University of Technology, Department of Social Sciences, Technology and Arts, Humans and Technology. School of Psychology and Computer Science, University of Central Lancashire, Preston, UK.
    The Categorical Deviation Effect May Be Underpinned by Attentional Capture: Preliminary Evidence from the Incidental Recognition of Distracters2023In: Auditory Perception & Cognition, ISSN 2574-2442, Vol. 6, no 1-2, p. 20-51Article in journal (Refereed)
    Abstract [en]

    The performance of a visual focal task is appreciably disrupted by an unexpected change (or deviation) in the properties of a task irrelevant auditory background. A vast amount of evidence suggests that a change in the acoustic properties of sound disrupts performance via attentional capture. However, an emerging body of evidence suggests that the disruption of task performance by a change in semantic category within a stream of sounds does not behave the same and is therefore not produced by attentional capture. This preliminary study aimed to further investigate whether the disruption produced by a categorical deviant was underpinned by attentional capture. In a single experiment, participants were presented with an irrelevant sound stream while they memorized a categorized list for free recall. We examined whether free recall performance was disrupted by an unexpected change in category within the sound and later investigated, via a surprise recognition test, whether participants had superior memory for deviant items as compared to items from the same positions in control sequences. Results revealed that the categorical deviation effect manifested in poorer free recall performance. Additionally, post-study, participants demonstrated better recognition memory for deviant items compared to control items. On the assumption that explicit recognition requires attentional encoding of deviant items, our results yield evidence that the categorical deviation effect may indeed be produced via attentional capture.

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  • Söderqvist Wermelin, Albert
    Förstudie om byggande av parkeringshus i Kvarnberget i Karlstad2023Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The background for this degree project being carried out is that there are not enough parking spaces in Karlstad Municipality. Then an idea came from Veidekke's side to break out the rock in Kvarnberget to build parking spaces.

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  • Baş, Yağmur
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Berglund, Linn
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Niittylä, Totte
    Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 87 Umeå, Sweden.
    Zattarin, Elisa
    Laboratory of Molecular Materials, Division of Biophysics and Biotechnology, Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping, Sweden.
    Aili, Daniel
    Laboratory of Molecular Materials, Division of Biophysics and Biotechnology, Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping, Sweden.
    Sotra, Zeljana
    Center for Disaster Medicine and Traumatology, Department of Biomedical and Clinical Sciences, Linköping University, SE-581 85 Linköping, Sweden.
    Rinklake, Ivana
    Center for Disaster Medicine and Traumatology, Department of Biomedical and Clinical Sciences, Linköping University, SE-581 85 Linköping, Sweden.
    Junker, Johan
    Center for Disaster Medicine and Traumatology, Department of Biomedical and Clinical Sciences, Linköping University, SE-581 85 Linköping, Sweden.
    Rakar, Jonathan
    Center for Disaster Medicine and Traumatology, Department of Biomedical and Clinical Sciences, Linköping University, SE-581 85 Linköping, Sweden.
    Oksman, Kristiina
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science. Department of Mechanical & Industrial Engineering (MIE), University of Toronto, Toronto, Ontario M5S 3G8, Canada.
    Preparation and Characterization of Softwood and Hardwood Nanofibril Hydrogels: Toward Wound Dressing Applications2023In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602Article in journal (Refereed)
    Abstract [en]

    Hydrogels of cellulose nanofibrils (CNFs) are promising wound dressing candidates due to their biocompatibility, high water absorption, and transparency. Herein, two different commercially available wood species, softwood and hardwood, were subjected to TEMPO-mediated oxidation to proceed with delignification and oxidation in a one-pot process, and thereafter, nanofibrils were isolated using a high-pressure microfluidizer. Furthermore, transparent nanofibril hydrogel networks were prepared by vacuum filtration. Nanofibril properties and network performance correlated with oxidation were investigated and compared with commercially available TEMPO-oxidized pulp nanofibrils and their networks. Softwood nanofibril hydrogel networks exhibited the best mechanical properties, and in vitro toxicological risk assessment showed no detrimental effect for any of the studied hydrogels on human fibroblast or keratinocyte cells. This study demonstrates a straightforward processing route for direct oxidation of different wood species to obtain nanofibril hydrogels for potential use as wound dressings, with softwood having the most potential.

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  • Nygren, Eva L.
    Luleå University of Technology, Department of Health, Learning and Technology.
    Elevers inställning till kamrathandledning med testbaserat lärande inom fysikundervisningen i högstadiet.: Utvecklingsarbete - kompletterande pedagogisk utbildning2023Student paper other, 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Syftet med utvecklingsarbetet är att på vetenskaplig grund bepröva erfarenheter genom att kritisk granska och utvärdera den egna undervisningen. Undervisningen har planerats och genomförts inom en lektionsserie i ämnet fysik som en del av den sista VFU-praktiken i kompletterande pedagogisk lärarutbildning (KPU).

    Den specifika frågeställningen som undersökts berör elevers attityder till en undervisnings-metod i som innefattar kamratlärande och testbaserad lärande som kallas Peer Instruction (PI). Metoden använts och utvärderats som en del av fysikundervisningen i två klasser i årskurs nio i en grundskola i storstockholmsområdet.

    För att utvärdera elevernas inställning till metoden har två enkät-undersökningar genomförts i de båda klasserna vid två olika tillfällen, före och efter genomförd lektionsserie. Två avslutande intervjuer med fokusgrupper har kompletterat analysen av enkätsvaren.

    Resultatet visar att eleverna i undersökningen var positivt inställda till kooperativa undervisningsmetoder inom fysikundervisningen och de upplever att de lär sig saker genom att ta hjälp av varandra. Det finns dock en bred fördelning i elevernas preferenser till hur man lär sig fysik på ett effektivt sätt. Eleverna hade en tydligt positiv inställning till PI-metoden i fysikundervisningen. En stor andel av eleverna upplevde de både lärde sig fysik på effektivt sätt och fick fördjupad förståelse för fysiken med hjälp av metoden. För att få fördjupad förståelse för användbarheten av undervisningsmetoden inom fysikämnet i högstadiet behöver den utvärderas i fler klassrum och på skolor med andra socioekonomiska förutsättningar.  

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