High-Entropy Oxides for Thermoelectric Application

High-entropy oxides (HEOs) are a new class of single-phase inorganic materials with a high specific capacity, high structural stability, and super-electronic conductivity and exhibit a wide range of useful properties. HEOs are better semiconductor materials compared to traditional ones due to their lattice distortion. Because parameters, such as crystal symmetry, different lattice parameters, etc., have a significant influence on the thermal conductivity of the material, lowering it via phonon-phonon or phonon-electron scattering. The entropy stabilization produces the high stability of the phase but also can result in interesting properties of the materials due to the contribution of different elements through four main effects: high-entropy effect, severe lattice distortion, sluggish diffusion effect, and cocktail effect. This thesis identified potential HEOs with the chemical composition Co-Cr-Fe-Mn-Ni-O by doing a thorough literature review. During the research, we have focused on the synthesis process and electrical properties of the HEOs (Co0.33Cr0.22Fe0.22Mn0.11Ni0.11)3O4, (Co0.33Cr0.22Fe0.22Mn0.11Cu0.11)3O4, and (Co0.2Cr0.2Fe0.2Mn0.2Cu0.2)3O4. Oxides were synthesized via Spark Plasma Sintering and Solid-State Reaction resulting in obtaining two or more phases with different crystal structures for the materials (Co0.33Cr0.22Fe0.22Mn0.11Ni0.11)3O4, and single-phased for the (Co0.33Cr0.22Fe0.22Mn0.11Cu0.11)3O4 and (Co0.2Cr0.2Fe0.2Mn0.2Cu0.2)3O4 at specific synthesis conditions. As expected, obtained single-phased materials exhibit higher values of electrical conductivity, which is probably due to the less electron-phonon scattering. Two types of semiconductors are needed for thermoelectric applications: p- and n-type. Due to the different synthesis temperatures, materials with Ni were obtained in both types. This can lead to the production of the Peltier module with the same chemical composition inside. With the Ni-Cu substitution, it became easier to produce single-phased materials, probably due to the melting point of the reagents. These materials also presented higher electrical properties, which the changes in carrier concentration can explain due to the differences in the electronic structures. All obtained samples exhibit low values of the electronic part of thermal conductivity, which can lead to low values of total thermal conductivity. It shows that the main contributor to the thermal conductivity will be from the phonons (lattice thermal conductivity). Overall, the expected thermal conductivity for these materials should be lower compared to the traditional semiconductor materials due to the crystal distortion, which can lead to higher phonon-phonon and phonon-electron scattering. Furthermore, this research shows that HEOs with unequal content of metals can be produced as single-phase materials and have even better or similar electrical properties compared to known compositions. Also, these oxides with impurities still exhibit promising electrical properties

Assessment of self-reported heart rate-increasing physical activity and perceived stress levels among students at Luleå university of technology : A survey study

Bakgrund: Stress är ett växande folkhälsoproblem och förekommer i hög grad bland universitetsstudenter. Tidigare forskning visar att studenter ofta rapporterar högre nivåer av stress, oro och ångest jämfört med jämnåriga yrkesverksamma. Långvarig stress kan ge negativa konsekvenser för både den psykiska och fysiska hälsan. Pulshöjande fysisk aktivitet har visat sig fungera som en skyddsfaktor mot stress. Syfte: Syftet med studien var att undersöka självskattad pulshöjande fysisk aktivitet och upplevd stress hos studenter vid Luleå tekniska universitet (LTU), samt att analysera skillnader avseende kön, ålder och utbildningsår. Metod: Studien var en observationsstudie. Data samlades in genom en egenkonstruerad anonym enkät som besvarades av 84 studenter vid LTU. Enkäten mätte självskattad fysisk aktivitetsnivå, upplevd stress samt hur dessa upplevdes påverka hälsan. Data analyserades genom deskriptiv statistik, Spearmans rangkorrelation och Mann-Whitney U-test. Resultat: Ett svagt men statistiskt signifikant negativt samband identifierades mellan pulshöjande fysisk aktivitet och upplevd stress (rho = −0,23, p <0,05). Inga signifikanta skillnader i stressnivå eller aktivitetsnivå observerades mellan män och kvinnor, och inga signifikanta samband påvisades mellan stress- och aktivitetsnivå i relation till ålder eller utbildningsår. Majoriteten av deltagarna uppgav att fysisk aktivitet förbättrade deras psykiska mående och minskade stressnivån efter träningspass. Konklusion: Resultaten indikerar att regelbunden pulshöjande fysisk aktivitet kan bidra till minskad upplevd stress och förbättrat psykiskt välbefinnande hos universitetsstudenter, även om sambandet är svagt. Fysisk aktivitet bör därför ses som en relevant strategi inom stressförebyggande arbete i studentmiljöer.Background: Stress is a growing public health problem and is highly prevalent among university students. Previous research shows that students often report high levels of stress and anxiety. Prolonged stress can lead to negative consequences for both physical and mental health. Physical activity has been shown to function as a protective factor against stress. Aim: The aim of this study was to investigate self-reported heart rate–increasing physical activity and perceived stress among students at LTU, and analyze differences between gender, age, and year of study. Method: An observational study design was used. Data was collected through a self-developed anonymous questionnaire completed by 84 students. The questionnaire measured selfreported physical activity level, perceived stress, and how these affected the perceived health. Data was analyzed using descriptive statistics, Spearman’s rank correlation, and the Mann– Whitney U test. Results: A weak but statistically significant negative correlation was identified between heart rate– increasing physical activity and perceived stress (rho = −0.23, p < 0.05). No significant differences in stress level or physical activity level were observed between genders, and no significant associations were found between stress or activity in relation to age or year of study. Most participants reported that physical activity improved their psychological health and reduced stress. Conclusion: These results indicate that regular heart rate–increasing physical activity may contribute to reduced stress and improve mental well-being among university students, although the association is weak. Physical activity should be considered a relevant strategy in stresspreventive efforts within university settings

People’s experience of living with heart failure : literature review

Bakgrund: Hjärtsvikt är en kronisk och livspåverkande sjukdom, där hjärtat inte längre orkar arbeta tillräckligt effektivt för att försörja kroppen med det blod och syre som behövs. Detta leder ofta till symtom som andfåddhet, uttalad trötthet och svullnad, och påverkar successivt personers möjlighet att orka med vardagliga aktiviteter. Sjukdomen innebär inte bara fysiska begränsningar, utan kan även få sociala och känslomässiga konsekvenser för både personen som är sjuk och för anhöriga. För att kunna erbjuda en personcentrerad vård är det därför betydelsefullt att få en fördjupad förståelse för hur personer själva beskriver sin vardag med hjärtsvikt. Syfte: Syftet med denna litteraturstudie var att beskriva personers upplevelse av att leva med hjärtsvikt. Metod: Studien genomfördes som en litteraturstudie med kvalitativ innehållsanalys. Systematiska sökningar utfördes i PubMed och CINAHL, vilket resulterade i elva vetenskapliga artiklar som kvalitetsgranskades med SBU:s granskningsmall. Resultat: Analysen resulterade i nio kategorier som beskrev personers erfarenheter av att leva med hjärtsvikt: Att roller förändras och ha ett ökat stödbehov, Att ha ett begränsat socialt liv och leva med ensamhet, Att leva med skuld, skam och stigma relaterat till hjärtsvikt, Att möta chock, sorg och förlorad kontroll vid diagnosen hjärtsvikt, Att leva med symtom som väcker rädsla och strategier för att hantera sjukdomen, Att ha nattliga uppvaknanden och påverkan på dagen, Att känna begränsningar i vardagslivet, Att anpassa kost och vätskeintag – en kamp mellan rekommendationer och invanda beteenden, Att sakna kunskap, vägledning och förutsättningar för egenvård. Slutsats: Att leva med hjärtsvikt innebär omfattande livsförändringar och ett stort behov av stöd från vården. En personcentrerad omvårdnad med tydlig information, kontinuerlig uppföljning och stöd till både personer och anhöriga är betydelsefull för att stärka egenvård, trygghet och livskvalitet

An investigation of mechanical, corrosion and high-temperature oxidation behaviors on designed Ti-based entropic alloys

To satisfy the high performance requirements of new generation materials in application of aerospace and automotive industries, a series of TiZrHf-based entropic (i.e., entropy-stabilized) alloys with α+β dual-phase microstructure were designed using the CALPHAD (CALculation of PHAse Diagram) methodology. The present work aimed to achieve an balanced performance between mechanical properties, corrosion resistance, and high-temperature oxidation stability by tailoring Zr/Hf ratios. The alloys were comprehensively characterized using X-ray diffraction (XRD), electron channeling contrast imaging (ECCI), and high angle annular dark field scanning transmission electron microscope (HAADF-STEM). Due to the effect of transformation-induced plasticity (TRIP), the homogenized and cryogenic alloys exhibit balanced mechanical properties (i.e., high strength and ductility). Electrochemical tests in 3.5 wt% NaCl solution demonstrated good corrosion resistance, and the stability of the passive film was slightly compromised by both cryogenic treatment and Zr/Hf additions. Moderate high-temperature oxidation tests at 500 and 600 °C showed that the alloys have good oxidation resistance result from the formation of protective scales dominated by TiO2 and Al2O3. However, the formation of less-protective Zr/Hf-oxides at higher temperatures (700 °C) was found to be detrimental. This work provide a CALPHAD-guided design strategy for developing Ti-based entropic alloys with a well-balanced properties for applying in different severe environments.Full text: CC BY license;For funding information, see: https://doi.org/10.1016/j.jmrt.2025.12.182</p

Triboelectric Nanogenerators for Future Space Missions

Space exploration is significant for scientific innovation, resource utilization, and planetary security. Space exploration involves several systems including satellites, space suits, communication systems, and robotics, which have to function under harsh space conditions such as extreme temperatures (− 270 to 1650 °C), microgravity (10⁻⁶ g), unhealthy humidity (&lt; 20% RH or &gt; 60% RH), high atmospheric pressure (~ 1450 psi), and radiation (4000–5000 mSv). Conventional energy-harvesting technologies (solar cells, fuel cells, and nuclear energy), that are normally used to power these space systems have certain limitations (e.g., sunlight dependence, weight, degradation, big size, high cost, low capacity, radioactivity, complexity, and low efficiency). The constraints in conventional energy resources have made it imperative to look for non-conventional yet efficient alternatives. A great potential for enhancing efficiency, sustainability, and mission duration in space exploration can be offered by integrating triboelectric nanogenerators (TENGs) with existing energy sources. Recently, the potential of TENG including energy harvesting (from vibrations/movements in satellites and spacecraft), self-powered sensing, and microgravity, for multiple applications in different space missions has been discussed. This review comprehensively covers the use of TENGs for various space applications, such as planetary exploration missions (Mars environment monitoring), manned space equipment, In-orbit robotic operations /collision monitoring, spacecraft's design and structural health monitoring, Aeronautical systems, and conventional energy harvesting (solar and nuclear). This review also discusses the use of self-powered TENG sensors for deep space object perception. At the same time, this review compares TENGs with conventional energy harvesting technologies for space systems. Lastly, this review talks about energy harvesting in satellites, TENG-based satellite communication systems, and future practical implementation challenges (with possible solutions).Full text: CC BY license;</p

Hydrogen embrittlement mitigation by surface modification: A review on current advances and future perspectives

Hydrogen is emerging as a sustainable energy source that can reduce fossil fuel reliance and associated environmental impact. However, it poses embrittlement challenges for storage and transport materials that affect the widespread deployment of the hydrogen economy. Surface modification of materials by employing coatings, thermochemical, mechanical treatments, and others modifies surface chemistry, microstructure, stress states, and enhances surface integrity. These surface modification methods form physical or chemical barriers that impede hydrogen permeation and lower hydrogen-induced degradation. Though an unfavorable combination of thermodynamic properties, hydrogen solubility, and hydrogen diffusivity of the modified surfaces promotes hydrogen embrittlement mechanisms. This review focuses on a comprehensive overview of various surface modification techniques applied to base materials to counter their hydrogen embrittlement susceptibility. This work emphasizes the relationship between the surface modification methods and their effects on microstructural and mechanical properties, and their contribution to hydrogen storage and transport solutions. Additionally, limitations, challenges, and research gaps related to these surface modification techniques for materials in hydrogen infrastructure are discussed.Full text: CC BY license;</p

Inpatient nurses' experience of mental health as a consequence of care during covid-19 pandemic

Bakgrund: Arbetsrelaterad mental ohälsa är ett värdsomspännande problem som kan leda till kognitiva, kroppsliga och emotionella problem. Sjuksköterskors arbete inom slutenvården med patienterna var intensivt under pandemins förlopp. Enligt rapportering till Världsoorganisationen blev över 70 000 patienter inskrivna på sjukhus per vecka världen över under covid-19 pandemins kulmen från början av 2021-2022. Syfte: Studiens syfte var att belysa sjuksköterskors upplevelse av psykisk hälsa som konsekvens av omvårdnadsarbetet i slutenvården under covid-19 pandemin. Metod: Studien genomfördes som en kvalitativ innehållsanalys med manifest ansats. Litteratursökningen genomfördes i PubMed, Medline och CINAHL vilket resulterade i 10 kvalitativa artiklar som bearbetades i analysen. Resultat: Analysen resulterade i fyra huvudkategorier: Att pandemin är källa till psykiskt lidande. Att konfronteras med maktlöshet, död och moralisk stress. Att böra vårdens börda till pris av egen hälsa. Att finna styrka, gemenskap och utveckling trots trauma. Slutsats: Sjuksköterskor som arbetat inom slutenvården under pandemin beskriver upplevelser av att plikttroget utföra sitt arbete och trycka undan de egna känslorna under pandemin och nu befinner sig i ett efterförlopp med utbrändhet, PTSD och empati trötthet till följd av detta. Resultatet indikerar att mer forksning behövs inom detta relativt outforskade område, för att kunna säkerställa en god arbetsmiljö för sjuksköterskor i framtiden.

Advances in MoS2 composites for electrocatalytic energy conversion: Synthesis, applications, and future perspectives in hydrogen, oxygen, nitorgen, and CO2 reactions

The significant increase in energy demand and environmental challenges requires sustainable technologies to preserve the climate and minimize CO2 emissions. Electrocatalysis for energy conversion applications, such as hydrogen evolution reaction (HER), oxygen evolution reaction (OER), nitrogen reduction reaction (NRR), and CO2 reduction reactions (CCR), are essential in renewable energy technologies. State-of-the-art catalysts are highly needed to enhance energy conversion efficiencies. Recently, Molybdenum disulfide (MoS2) with its distinguished physiochemical properties has been verified as a potential energy conversion material for catalyzing electrochemical reactions, ensuring excellent performance.Aside from graphene, which is unsuitable in some fields due to its zero-energy bandgap, alternative 2D materials like MoS2 have been developed and investigated. MoS2 nanostructures, with a relatively brief history, are emerging as suitable candidates in several applications, especially in electrocatalysis. Enhancing charge transfer and combining MoS2 with other materials can improve energy and environmental application performance.The excellent electrocatalytic progress of MoS2-based composites has been reported alongside enhanced and tunable properties like rich active edges, high density of structural defects, excellent conductivity, well-defined size dispersion, good electrode contact, favorable exposed crystal facets, and maximized phases. These properties, critical in electrocatalysis, are reviewed herein.We describe different methodologies for preparing MoS2 composite materials, illustrating their advantages and limitations for catalysis applications. We discuss the figure of merit of MoS2 composite nanostructures in electrocatalysis and present the challenges and outlooks for this new material class based on recent developments and potential applications in energy and the environment, suggesting promising research directions for the future.Validerad;2025;Nivå 2;2025-11-25 (u4);Funder: Pakistan Science Foundation and the National Natural Science Foundation of China (PSF-NSFC/202307/427); UK Carbon Capture and Storage Research Centre (UKCCSRC);Fulltext license: CC BY</p

Emerging Role of 2D Materials in Photovoltaics: Efficiency Enhancement and Future Perspectives

The growing global energy demand and worsening climate change highlight the urgent need for clean, efficient and sustainable energy solutions. Among emerging technologies, atomically thin two-dimensional (2D) materials offer unique advantages in photovoltaics due to their tunable optoelectronic properties, high surface area and efficient charge transport capabilities. This review explores recent progress in photovoltaics incorporating 2D materials, focusing on their application as hole and electron transport layers to optimize bandgap alignment, enhance carrier mobility and improve chemical stability. A comprehensive analysis is presented on perovskite solar cells utilizing 2D materials, with a particular focus on strategies to enhance crystallization, passivate defects and improve overall cell efficiency. Additionally, the application of 2D materials in organic solar cells is examined, particularly for reducing recombination losses and enhancing charge extraction through work function modification. Their impact on dye-sensitized solar cells, including catalytic activity and counter electrode performance, is also explored. Finally, the review outlines key challenges, material limitations and performance metrics, offering insight into the future development of next-generation photovoltaic devices encouraged by 2D materials.Validerad;2025;Nivå 2;2025-10-02 (u5);Full text license: CC BYFor funding information, see: https://link.springer.com/article/10.1007/s40820-025-01869-z#Fun</p

Solvent extraction using crown ethers: Selective recovery of potassium from synthetic K-feldspar leachate

The present study focuses on the selective extraction of potassium from a hydrochloric acid-based feldspar leachate using solvent extraction with crown ethers, CE (dibenzo-18-crown-6 and 12-crown-4). The effects of hydrochloric acid concentration, extractant type, diluent, extractant concentration, and organic-to-aqueous phase ratio on potassium extraction efficiency have been examined. Dibenzo-18-crown-6 diluted in m-cresol was shown to preferentially extract potassium (≈85 %) from highly acidic hydrochloric acid solutions (2 to 6 M), with minimal co-extraction of impurities, such as aluminum and sodium, in a single extraction step. Aluminum, however, was shown to be extracted efficiently (≈99 %) at lower acidities (&lt;0.1 M). The extraction mechanisms were explored using various analyses, such as slope analysis, nuclear magnetic resonance, and scanning electron microscopy showing that dibenzo-18-crown-6 forms a highly stable complex with potassium at 1:1 M ratio, (KCl)(CE), driven by the size compatibility between potassium ions and the crown ether cavity. For aluminum, the extraction mechanism likely involves the formation of a cooperative complex where aluminum ions are associated with the potassium-crown ether complex (AlKCl4)(CE). Increasing the concentration of hydrochloric acid increased potassium ion activity, chloride ion activity, and ionic strength in the solution. These changes would enhance selective potassium extraction over the formation and extraction of the aluminum‑potassium cooperative complex.Validerad;2025;Nivå 2;2025-11-12 (u2);Full text: CC BY license;POTASSIA