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Exploring the role of ore texture in comminution and approaches to identify and promote non-random breakage
No full textUnderstanding ore texture is essential for optimising comminution and mineral liberation, yet no standardised framework exists for defining and quantifying textural attributes. This review explores the complex relationship between ore texture, breakage mechanisms, and mineral liberation, emphasising the importance of textural parameters such as grain size, mineral intergrowths, and mechanical properties in determining comminution behaviour. The review is structured into key themes: (i) characterisation techniques for ore texture, spanning optical, electron beam, X-ray, and laser-based methods; (ii) conventional and proxy comminution tests for assessing ore hardness and breakage response; (iii) modelling approaches to relate ore texture to mineral liberation, including texture-based and kinetic-based liberation models; and (iv) innovative pre-treatment methods such as microwave heating, high-voltage pulse disintegration, and ultrasonication, which aim to promote non-random breakage and improve mineral liberation. The literature is analysed through a comparative assessment of these methods, evaluating their applicability, limitations, and integration potential in modern mineral processing. Key takeaways include the need for a standardised classification of ore texture, at least for mineral processing purposes, improved methods for quantifying breakage modes, and the development of more accurate liberation models that incorporate textural heterogeneity. While advanced pre-treatment techniques show promise in promoting non-random comminution, their widespread adoption remains constrained by energy consumption and economic feasibility. By synthesising recent advancements and identifying research gaps, this review contributes to the field by advocating for a geometallurgical approach that integrates ore texture characterization into comminution models. Validerad;2025;Nivå 2;2025-05-26 (u8);Funder: Centre of Advanced Mining and Metallurgy (CAMM);Full text license: CC BY</p
Digital tools and motivation : A study into how digital tools affect the motivation of students in F–3 to automate the multiplication table
No full textI den här studien undersöktes det hur motivationen påverkades av att använda digitala verktyg för att automatisera multiplikationstabellerna och om det fanns någon skillnad mellan årskurs 2 och 3. Därtill undersöktes det även om det fanns något samband mellan motivationen kopplad till de digitala verktygen och den inre motivationen. I undersökningen deltog 36 elever jämt delat mellan årskurserna. Under tre tillfällen fick eleverna träna på multiplikationstabellerna via en hemsida på varsin iPad. Efter de tre tillfällena var slutförda svarade eleverna på en anonym enkät som behandlade motivation utan och med digitala verktyg. För årskurs 2 skedde en statistiskt signifikant ökning av motivationen, medan motivation förblev lika för årskurs 3. Det kunde även identifieras en medelstor positiv korrelation mellan motivationen att använda digitala verktyg och den inre motivationen
EU:s förbud mot personbilsmarknaden : En empirisk studie om begreppet marknadsmisslyckande
No full textPersonbilsmarknaden inom EU har under de senare åren påbörjat ett skifte från användandet av fossildrivna motorer till helt elektrifierade drivlinor. Denna ‘gröna omställning’ är pådriven av att all försäljning av fossildrivna personbilar ska förbjudas helt starten av år 2035 enligt EU:s bestämmelser. År 2024 såg tillväxttakten av elbilsförsäljningen avta och marknaden slås av en ökad konkurrenssituation och ett alltmer osäkert världsekonomiskt läge. Denna studie ämnar att förklara hur EU:s regler kring nybilsförsäljningen påverkat marknaden på kort sikt och hur utvecklingen fram till år 2035 kan komma att se ut. För att besvara detta har försäljningssiffror för de åtta största tillverkarna på den europeiska personbilsmarknaden samlats in samt deras årsredovisningar för år 2024 lästs för att utröna vad dessa förmedlar i förhållande till teorin om marknadsmisslyckande. Genom tematisk analys har underlaget kodats och kategoriserats till nio teman som användes för att beskriva detta. Vad som framgår ur materialet är att marknaden är präglad av sviktande efterfrågan och en osäkerhet kring framtida regleringar. För att hantera detta väljer många tillverkarna att satsa på elektrifiering men även att ha kvar sitt utbud av fossildrivna bilar, där vinstmarginaler är större än för elbilar och efterfrågan fortfarande finns kvar. Dessa kommer sannolikt att vara en stor del av marknadsutbudet tiden fram till EU:s förbud träder i kraft. I dagsläget är elbilar dyra och flera tillverkare uttrycker att statliga incitament kommer behövas för att påskynda marknadens acceptans av dessa. Prognosen för marknaden tros även bero på utvecklingen av infrastruktur för laddning av elbilsbatterier. Tolkningen är att EU:s regleringar av personbilsmarknaden är en ambition att minska den negativa miljöpåverkan som fossildrivna bilar bidrar till, men det ansträngda läget som tycks finnas på marknaden kan leda till andra marknadsmisslyckanden. Om efterfrågan på elbilar inte ökar kan det påverka tillverkare negativt och försätta dessa i en ansträngd sits där dessa kan tvingas agera drastiskt för att hantera situationen, om inte EU reviderar sina regler. Framtiden för personbilsmarknaden inom EU är osäker och fram till 2035 kan flera scenarier falla ut. Den gröna omställningen kommer otvivelaktigt att ske, frågan är bara hur tidshorisonten faktiskt kommer att se ut. The passenger car market in the EU has begun a shift from the use of fossil fuelled cars to fully electric drivelines. This ‘green transition’ is driven by a ban on sales of fossil fuelled passenger cars by the start of year 2035, as per EU:s legislation. Year 2024 saw a drop in growth of electric car sales and the market being struck by increased competition as well as growing uncertainty in the world's economy. This study aims to explain how the EU:s regulation of new passenger car sales has affected the market in the short term and how developments to the year 2035 might form. To answer this, sales figures from the eight leading passenger car manufacturers on the European market have been collected, as well as having read their annual reports on the year 2024 to find out what these convey in terms of the theory on market failure. Through thematic analysis, the gathered material has been coded and themed into nine categories that are then used to describe market failure in this context. What is apparent is that the market is in a state of wavering demand and uncertainty regarding future regulations. To cope with this, many manufacturers choose to invest in electrification, but simultaneously retain their offerings of fossil fuelled cars, where profit margins are larger than electric cars and demand is still there. These will likely be a significant part of the market until the ban from the EU becomes a reality. Currently, electric cars are expensive to purchase and several manufacturers express that government subsidies will be necessary to accelerate the markets’ acceptance of these vehicles. How the market plays out is thought to be closely related to the development of charging infrastructure for electric vehicles. The EU:s regulations of the passenger car market is assumed to be shaped to achieve a reduction in the negative environmental impact fossil fuelled cars contribute to, but the strained situation the market finds itself in might lead to other market failures. If demand for electric cars does not increase, it could affect manufacturers negatively and put them in a challenging position where drastic measures may have to be employed, unless the EU reevaluates its rules. The future of the passenger car market in the EU until the year 2035 is uncertain and several scenarios may play out. The green transition will undoubtedly happen, the question, though, is when it will occur.
Thermal comfort before and after energy efficiency improvements : A study of a million programme residential area in a subarctic climate
No full textFlerbostadshusen från miljonprogrammet har nått sin tekniska livslängd och dessa områden står nu inför stora renoveringsbehov. Det finns stora möjligheter att genom dessa renoveringar genomföra åtgärder för att minska energianvändningen. En viktig faktor att beakta vid energirenoveringar är inomhusklimatet, vilket för de boende i många fall upplevs som en viktigare faktor än den minskade energianvändningen. De flesta studier som undersökt inomhusklimatet i form av termisk komfort, efter en energirenovering, har tillämpat simuleringar och enkätstudier. En begränsning med simuleringar är att det inte alltid visar på hela verkligheten, medan enkätstudier endast visar den subjektiva faktorn. Denna studie syftar till att analysera termisk komfort före och efter energieffektivisering för att bidra till ökad kunskap för fastighetsägare som står inför beslut om energirenoveringar i framtiden. Målet är att genom mätningar och strikt strukturerade intervjuer analysera vilka faktorer som har stor påverkan på den termiska komforten och hur den termiska komforten påverkats efter en energieffektivisering. Som en del i ett större forskningsprojekt har denna studie nyttjat ett flerbostadshusområde i Luleå för att undersöka termisk komfort före och efter energirenovering under samma väderförhållanden. Området består av flerbostadshus som ägs av tre olika fastighetsägare och där några av husen genomgått en energieffektivisering. För insamling av empirin samlades data dels från ej energirenoverade hus dels från energirenoverade hus. Mätningar av temperatur, luftfuktighet och lufthastighet genomfördes, i olika rum, i 10 lägenheter som inte genomgått en energirenovering. Vidare placerades sensorer ut i hallen i dessa lägenheter för att mäta lufttemperatur och relativ fukthalt under en tvåveckorsperiod. Mätningarna kompletterades med strikt strukturerade intervjuer med boende i dessa lägenheter för att även undersöka den subjektiva upplevelsen. Dessa metoder syftade till att identifiera faktorer som har stor påverkan på den termiska komforten. Därtill har temperatur- och fuktdata från de energirenoverade husen, under samma tvåveckorsperiod, tillhandahållits från respektive fastighetsägare för att analysera hur den termiska komforten kan påverkas vid en energirenovering. Resultaten analyserades och presenterades därefter på en workshop tillsammans med fastighetsägarna på området där tolkningar diskuterades. Resultaten visade på att temperaturen varierade mellan olika positioner och rum i byggnaden i de ej energirenoverade husen. Det fanns även stora variationer i temperaturen inom varje lägenhet under tvåveckorsperioden. Återkommande åsikter från de boende var upplevelsen av drag från ventiler och kalla golv. De energirenoverade husen hade mindre variationer mellan olika positioner och mer stabila inomhustemperaturer uppvisades. Inomhusluften var torr i husen både före och efter energirenovering. På grund av variationerna i temperatur mellan olika positioner och inom varje lägenhet, i de ej energirenoverade husen, drogs slutsatsen att det fanns ett stort beroende av solexponering. Vidare noterades att boendevanor påverkade den termiska komforten genom bland annat reglering av radiatorer. Därtill konstaterades hur termostater på radiatorer var en viktig aspekt till att kontrollera inomhustemperaturen både före och efter energirenovering. Efter energirenoveringen skapades ett stabilare inomhusklimat, vilket bedömdes bero på ett tätare klimatskal och uppgraderingen av ventilationssystem. Denna studie har bidragit till analys av den termiska komforten i ett flerbostadshusområde från miljonprogrammet både via subjektiva åsikter och fysiska mätningar. Studien är unik på så vis att den möjliggjort undersökning av energirenoverade och ej energirenoverade hus under precis samma väderförhållanden. Detta har ökat trovärdigheten och vetenskapligheten vid jämförelsen av olika faktorer. För fortsatta studier hade det varit intressant att bland annat genomföra fler mätningar på fler lägenheter före energirenovering, exempelvis under sommaren.The multi-family buildings from The Million Homes Programme have reached the end of their technical lifespan, and these areas are now facing significant renovation needs. These renovations offer major opportunities to reduce energy use. One important factor to consider during energy renovations is the indoor climate, which, for many residents, is perceived as more important than the actual reduction in energy consumption. Most studies examining indoor climate, specifically thermal comfort, after energy renovations have relied on simulations and surveys. A limitation of simulations is that they don’t always reflect reality, while surveys capture only the subjective perspective. This study aims to analyze thermal comfort before and after energy efficiency measures, in order to contribute valuable knowledge for property owners who are planning future energy renovations. The goal is to use measurements and strictly structured interviews to analyze which factors have a significant impact on thermal comfort and how thermal comfort is affected after an energy renovation. As part of a larger research project, this study utilized a multi-family housing area in Luleå to examine thermal comfort before and after energy renovations under the same weather conditions. The area consists of buildings owned by three different property owners, some of which have undergone energy efficiency upgrades. Data was collected from both renovated and non-renovated buildings. Measurements of temperature, humidity, and air velocity were conducted in various rooms in 10 apartments that had not been renovated. Additionally, sensors were placed in the hallways of these apartments to measure air temperature and relative humidity over a two-week period. The measurements were complemented with strictly structured interviews with the residents to also investigate the subjective experience. These methods aimed to identify factors that strongly influence thermal comfort. Furthermore, temperature and humidity data from the renovated buildings, collected during the same two-week period, were provided by the respective property owners to allow for a comparative analysis of thermal comfort before and after renovation. The results were analyzed and then presented during a workshop with the area’s property owners, where interpretations were discussed. The results showed that temperature varied between different positions and rooms in the non-renovated buildings, with significant variations within individual apartments over the two-week period. Residents frequently reported experiencing drafts from vents and cold floors. In contrast, the renovated buildings exhibited smaller temperature variations between different positions and more stable indoor temperatures. Indoor air was dry in both the pre- and post-renovation conditions. Due to the temperature variations between different positions and within each apartment in the non-renovated buildings, it was concluded that solar exposure had a major influence. Additionally, residents' habits, such as radiator adjustments, were found to affect thermal comfort. The study also emphasized the importance of radiator thermostats for regulating indoor temperature, both before and after renovation. After the renovations, a more stable indoor climate was achieved, which was attributed to a tighter building envelope and upgraded ventilation systems. This study has contributed to the analysis of thermal comfort in a Million Homes Programme residential area using both subjective opinions and physical measurements. It is unique in that it enabled a comparison of renovated and non-renovated buildings under the same weather conditions, increasing the credibility and scientific value of the comparison. For future studies, it would be valuable to conduct additional measurements in more apartments prior to renovation, ideally during other seasons such as summer
Electrochemical oxidation of polycyclic aromatic hydrocarbons in soil co-contaminated with arsenic
No full textThe wood preservation industry has contaminated numerous sites with polycyclic aromatic hydrocarbons (PAH). The aim of this study was to investigate the use of electrochemical oxidation (EO), without chemical additives, for in situ degradation of PAHs in soil co-contaminated with arsenic. Two 1 m3 boxes, each containing a 20 cm layer of contaminated sand overlaid with 20 cm of peat, were equipped with iron electrodes and placed outdoors. EO was applied using a pulsating direct current with alternating polarity, and its impact on PAH concentrations in soil and soil solution, as well as on the associated microbial community was assessed. Soil solution was sampled from the boxes over two seasons and analysed for PAH16 concentrations, showing an average decrease of 82 % by the end of the second season. This reduction was mainly observed in the medium and high molecular weight PAH fractions, suggesting that EO can effectively degrade more recalcitrant PAH compounds. The least reduction was seen in the low molecular weight PAH16, likely due to the replenishment from PAHs sorbed to the soil. Soil samples were taken from 12 different locations within the boxes, showing that PAH16 concentrations significantly decreased in 10 out of 12 sampling points, with a greater average reduction in sand (84 % decrease) compared to peat (69 % decrease). Microbial analyses of the soil samples revealed no significant changes in DNA concentrations across all taxa over time, with Gammaproteobacteria remaining the most abundant microorganisms in all samples, suggesting its ability to persist complex contamination.Validerad;2025;Nivå 2;2025-06-09 (u8);Full text license: CC BY</p
Geochemical footprints of IOA and IOCG deposits in Northern Norrbotten, Sweden, and Cloncurry District, Australia
No full textThis paper addresses the complex hydrothermal evolution of Metasomatic Iron and Alkali-Calcic (MIAC) mineral systems based on a review of the lithogeochemical footprints of IOA and IOCG deposits in the northern Norrbotten province (Sweden) and the Cloncurry district (Australia). The use of Na-Ca-Fe-K-Mg molar barcodes on a lithogeochemical diagram tailored for these mineral systems allows to depict the evolution of MIAC systems along diagnostic metasomatic paths from high (HT) to low temperature (LT) alteration facies as follows: 1) HT or LT Na alteration (300–1000 °C); 2) HT Ca Fe alteration (400–1000 °C); 3) HT K Fe alteration (350–450 °C); 4) HT K and HT K-Ca-Mg alteration; 5) LT K Fe, Na-Ca-Mg-Fe, and/or Na-Ca-Mg alteration (≤ ~350 °C); and 6) epithermal alteration (≤ 150 °C) and later stage hydrothermal veining. A distinct range of whole rock compositions and metal associations characterizes each alteration facies and can be captured by diagnostic molar barcodes and alteration indices. In northern Norrbotten, the IOA deposits are hosted in HT Ca Fe alteration facies but regionally intensely albitized regions are overprinted by K Fe alteration. The IOCG deposits are hosted in MIAC systems with zones of early Na ( Ca) alteration related to the regionally extensive albitite or scapolite alteration (Facies 1) and localized skarns. These are overprinted by HT Ca Fe alteration (Facies 2) and HT to LT K Fe alteration (Facies 3 and 5). The Cu Au mineralization is not systematically associated with the iron oxide-rich breccias and the intense K-feldspar- or sericite-rich K Fe alteration typical of many IOCG deposits worldwide. Instead, the lesser intensity of alteration and the abundance of mafic and ultramafic rocks in the environment lead to pattern enriched in Mg with relic of amphibole-rich alteration remaining in the assemblage as demonstrated for the Nautanen North IOCG deposit (Sweden). Consequently, the geochemical footprints of the Norrbotten Cu Au deposits are distinct from magnetite-group (e.g., Great Bear magmatic zone, Canada) and hematite-group (e.g., Olympic Dam, Australia) IOCG deposits even if they have all the known alteration facies of MIAC systems. Conversely, IOCG deposits in northern Norrbotten show similarities to certain deposits in the Cloncurry district of Australia. In both regions, the IOCG deposits are associated with HT Ca Fe and K Fe alteration facies that commonly overprint early Na and/or Na Ca alteration. In northern Norrbotten, IOA deposits are characterized by early Na alteration evolving towards Na Ca alteration, then Fe-rich Ca Fe alteration. These hydrothermal alteration types are subsequently superimposed by later K Fe alteration. We conclude that the use of Na-Ca-Fe-K-Mg molar barcodes provides new insights to understand the evolution of MIAC systems and is a powerful approach for unraveling superimposed alteration trends, which can serve as an exploration targeting tool from the district- to the deposit-scale in complex metasomatized areas.Validerad;2025;Nivå 2;2025-06-05 (u4);Fulltext license: CC BY</p
Induction Effect of Fluorine-grafted Polymer-based Electrolytes for High-Performance Lithium Metal Batteries
No full textQuasi-solid-state composite electrolytes (QSCEs) show promise for high-performance solid-state batteries, while they still struggle with interfacial stability and cycling performance. Herein, a F-grafted QSCE (F-QSCE) was developed via copolymerizing the F monomers and ionic liquid monomers. The F-QSCE demonstrates better overall performance, such as high ionic conductivity of 1.21 mS cm–1 at 25 °C, wide electrochemical windows of 5.20 V, and stable cycling stability for Li//Li symmetric cells over 4000 h. This is attributed to the significant electronegativity difference between C and F in the fluorinated chain (‒CF2‒CF‒CF3), which causes the electron cloud to shift toward the F atom, surrounding it with a negative charge and producing the inductive effect. Furthermore, the interactions between Li+ and F, TFSI‒, and C are enhanced, reducing ion pair aggregation (Li+‒TFSI‒‒Li+) and promoting Li+ transport. Besides, ‒CF2‒CF‒CF3 decomposes to form LiF preferentially over TFSI–, resulting in better interfacial stability for F-QSCE. This work provides a pathway to enable the development of high-performance Li metal batteries.Validerad;2025;Nivå 2;2025-05-15 (u4);Research funders: National Natural Science Foundation of China (No. U23A20122);Fulltext license: CC BY;This article has previously appeared as a manuscript in a thesis.</p
Utveckling och optimering av elektrodförband för neuromuskulär elektrisk stimulering (NMES) med fokus på design och användarvänlighet
No full textNeuromuscular electrical stimulation (NMES) is used to enhance muscle activity and circulation, particularly in individuals with reduced mobility. To improve treatment adherence, solutions must be comfortable, easy to use, and technically reliable. This thesis project, conducted in collaboration with Matrix Muscle Support (MMS), aims to develop an improved electrode patch and fixation solution for NMES treatment of the calf muscles.The project includes needs analysis, concept development, CAD-based design, and testing of two patch prototypes, one with 16 electrodes and one with 9. The fixation system was developed with a focus on ergonomics and self-application. Both patches and the fixation solution were designed using flexible materials, robust connection to the control module, and optimized electrode placement.The results show that the developed concepts meet high standards for function, usability, and manufacturability. The work contributes concrete improvements in product design and provides a foundation for further development and clinical validation of the system
Development and characterization of novel tannin-modified konjac glucomannan hydrogels with optimized crosslinking features
No full textKonjac glucomannan (KGM) is a non-toxic, biodegradable polysaccharide known for its excellent gel-forming properties and high water retention. This study presents a novel tannin-enhanced KGM hydrogel, tailored for controlled solvent release and improved surface adaptability in artwork cleaning applications. Hydrogel formulation consisting of KGM crosslinked with borax was optimized generating borax through the reaction of boric acid and sodium hydroxide. This resulted in uniformly crosslinked gels with improved tensile strength and high moisture retention, essential for controlled cleaning. Moreover, tannins were incorporated in the optimised KGM-based polymer matrices. This modification was introduced as a novel and sustainable strategy to enhance crosslinking, leveraging natural polyphenols to add functional properties. Two tannins were tested: a condensed tannin isolated from Vitis vinifera, and a hydrolyzable tannin isolated from oak, tannic acid. Tannins were incorporated either through hydrogen bonding or covalently. Covalent attachment was achieved using epichlorohydrin (ECH) to add an epoxide motif to the tannin, enabling covalent binding with KGM. The resulting gels were thoroughly characterized for their chemical, rheological and morphological properties, showing that novel crosslinking via in situ borax formation improved moisture retention and surface adaptability, while the incorporation of tannins enhanced water absorption, maintaining high retention and favorable mechanical properties.Validerad;2025;Nivå 1;2025-06-24 (u5);Full text license: CC BY 4.0;Funder: European Union – Next Generation EU; Italian Ministry of University and Research;</p
Nudging i projektledning : Projektledares upplevelser och utmaningar inom IT och byggbranschen
No full textThis thesis aims to understand how project managers perceive and apply nudging in two distinct sectors, the knowledge-intensive IT industry and the operational construction. Nudging, a concept from behavioral economics which refers to influencing decisions in a non-coercive manner. While nudging has gained traction in policy and marketing, its application in project management remains under-researched. Using a qualitative approach with semi-structured interviews, this study investigates how project managers apply nudging, the challenges they face, and how usage differs across industries. The findings reveal that nudging is frequently used unconsciously in both sectors. In construction, influence is primarily achieved through routines and visual tools, whereas IT project managers more often rely on social cues, self-leadership, and adaptive communication strategies. Contextual factors such as organizational culture and structure significantly affect nudging effectiveness. Despite its potential, challenges include lack of awareness, time constraints, and concerns about manipulation. This study contributes to the understanding of nudging as a practical leadership tool in project settings and highlights the need for further research and education in the field.Denna studie handlar om att förstå hur projektledare upplever och använder nudging inom tvåolika branscher, den kunskapsintensiva IT-branschen och den mer operativa byggbranschen.Nudging, som innebär att påverka beteenden utan att begränsa valmöjligheterna, har fått alltstörre uppmärksamhet men är fortfarande relativt outforskat inom projektledning. Genom enkvalitativ metod med semistrukturerade intervjuer har projektledares erfarenheter ochtillämpningar analyserats för att förstå hur nudging används i praktiken, vilka utmaningar somuppstår, samt hur användningen skiljer sig mellan branscherna. Resultaten visar att projektledare ofta använder nudging utan att benämna det. I byggbranschensker påverkan främst genom visuella hjälpmedel och rutiner, medan IT-projektledare tenderaratt använda mer sociala och kognitiva nudges i form av dialog, självledarskap och anpassningari projektmiljön. Studien visar att kontexten, som organisatorisk struktur och kultur, starktpåverkar hur nudging-strategier upplevs och implementeras. Trots positiva effekter finnsutmaningar kopplade till bristande kunskap, tidspress och risken för att nudging uppfattas sommanipulativ. Studien bidrar med ökad förståelse för hur nudging kan användas som ettstrategiskt verktyg i projektledning och pekar på behovet av vidare forskning och utbildninginom området