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  • Blad, Karin
    Örebro universitet, Institutionen för beteende-, social- och rättsvetenskap.
    Styrelseledamöters skyldigheter och ansvar vid risk för obestånd och liknande situationer2023Doctoral thesis, monograph (Other academic)
    Abstract [sv]

    Styrelseledamöter har ett antal skyldigheter när ett aktiebolag får ekonomiska svårigheter. Vilka regler som aktualiserar bolagsledningens ansvar beror på om ett aktiebolag har betalningsproblem eller balansproblem. Avseende balansproblemet finns regler om så kallat medansvar för styrelseledamöter och andra företrädare i 25 kap. aktiebolagslagen (2005:551). Syftet med kapitalbristreglerna är att tillse en snabb avveckling av ett kapitalsvagt aktiebolag och därvid skydda borgenärskollektivet. Utöver medansvarsreglerna finns det regler om skadeståndsansvar för bland andra styrelseledamöter för skador de åsamkar bolaget, aktieägare eller andra, exempelvis borgenärer. Vid ett aktiebolags betalningsproblem aktualiseras obeståndsrelaterade ansvarsregler i de fall betalningsoförmågan inte bedöms vara endast tillfällig. Härvid kan särskilt nämnas borgenärsbrotten i 11 kap. brottsbalken (1962:700), vilka förutsätter gäldenärens obestånd eller att påtaglig fara för obestånd föreligger. Därtill aktualiserar den särskilda oförmågan att betala förfallna skatteskulder det skatterättsliga företrädaransvaret i 59 kap. skatteförfarandelagen (2011:1244) (SFL) och för det räcker att betalningsoförmågan är endast tillfällig. Avhandlingen syftet är att systematisera och utvärdera reglerna om skyldigheter och personligt ansvar för styrelseledamöter när bolaget befinner sig i insolvenszonen, det vill säga när det är risk för obestånd eller obestånd är ett faktum. I syftet ingår att undersöka regleringens ändamålsenlighet.

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  • Eslahchi, Morteza
    Stockholms universitet, Institutionen för pedagogik och didaktik.
    Learning Together, Leading Change: Understanding Collective Learning in Social Entrepreneurial Organisations2023Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This dissertation aims to generate an understanding of collective learning in social entrepreneurial organisations in Sweden, especially during the COVID-19 pandemic. Employing a collective learning-centred perspective, I want to explore the following key areas: a) the learning conditions and organising processes entailed in becoming a social entrepreneur and creating a social entrepreneurial organisation, b) the importance of collective learning for organisational adaptation and change in tackling exogenous factors such as the COVID-19 pandemic, and c) the role of leadership in creating conditions conducive to collective learning processes in social entrepreneurial organisations during the COVID-19 pandemic.

    Grounded in empirical studies, this research reimagines leadership as an empowering, collaborative practice that is intricately woven with collective learning dynamics. The study also scrutinises the adaptive and evolutionary nature of organising processes, emphasising their centrality for collective learning. Furthermore, it highlights the efficacy of a collective learning-centred approach in driving meaningful organisational change, contrasting this with top-down strategies. Since most of the data was gathered during the global upheaval caused by COVID-19, this research presents a unique opportunity to examine collective learning as a resilience-building tool in turbulent times. This study fills a gap in existing literature by focusing on the Swedish context, and offers insights for researchers, practitioners, and policymakers in social entrepreneurship. Ultimately, the research underscores the potential of collective learning to equip social entrepreneurial organisations for sustainable innovation and resilience, particularly in challenging societal conditions.

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  • Eslahchi, Morteza
    Stockholms universitet, Institutionen för pedagogik och didaktik.
    Leadership and collective learning: a case study of a social entrepreneurial organisation in Sweden2023In: Learning Organization, ISSN 0969-6474, E-ISSN 1758-7905, Vol. 30, no 6, p. 815-833Article in journal (Refereed)
    Abstract [en]

    Purpose

    This paper aims to enrich the scholarly discourse on learning within small social entrepreneurial organisations by examining how leadership can facilitate conditions conducive to collective learning during crises.

    Design/methodology/approach

    A longitudinal single-case study was conducted on a social entrepreneurial organisation in Sweden, operating within the integration field. The study involved comprehensive interviews and observations. Using a longitudinal approach facilitated an in-depth analysis of the organisation’s development over time.

    Findings

    The findings underscore that shifts in leadership can significantly influence collective learning. Specifically, the results suggest that establishing trust between the CEO and team members is a pivotal factor in cultivating conditions for collective learning and fostering the related processes, which persisted even during the pandemic. This trust catalysed inclusive and interactive actions that encouraged team members’ participation in day-to-day decision-making and strategic planning. Consequently, the organisation successfully leveraged its diverse knowledge resources, promoting knowledge sharing and experience exchange, crucial components of successful collective learning.Research limitations/implicationsThis paper advocates for a departure from conventional leadership perspectives, proposing that a focus on team–leader relationships – a form of leadership in practice – can offer valuable insights into cultivating collective learning. This approach underscores the significance of collaboration and engagement among team members in promoting collective learning and accentuates the role of leadership in creating these conditions.

    Practical implications

    The examples provided on structuring, organising and leading virtual meetings could offer valuable insights for leaders. With the increasing adoption of hybrid workplaces combining remote and office environments, communication challenges within teams may arise. Therefore, these examples can aid leaders in formulating effective communication strategies that bridge the gap between remote and in-person team members, ensuring that everyone stays informed and engaged.

    Originality/value

    This study seized a unique opportunity to explore how leadership can create favourable conditions for collective learning during crises by collecting data both before and during the Covid-19 pandemic.

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  • Eslahchi, Morteza
    Stockholms universitet, Institutionen för pedagogik och didaktik.
    Adapting to the COVID-19 world: a case study of collective learning in a social entrepreneurial organisation2023In: Journal of Workplace Learning, ISSN 1366-5626, E-ISSN 1758-7859, Vol. 35, no 9, p. 50-65Article in journal (Refereed)
    Abstract [en]

    Purpose – This paper aims to examine how a social entrepreneurial organisation in Sweden collectively learned to adapt itself to the COVID-19 pandemic.

    Design/methodology/approach – Using an abductive approach, this study conducted single case fieldwork on a social entrepreneurial organisation called SFE. The following research questions were asked: What are the changes in collective learning conditions that SFE has to face during the pandemic? What are the outcomes of collective learning during the pandemic in SFE?

    Findings – This study results indicate that collective learning conditions were changed by restructuring the organisation’s design and teamwork during the pandemic, which facilitated sharing of knowledge and experiences. This collective learning helped the organisation develop new virtual projects during the pandemic. Another result of this collective learning was the members’ new shared understanding of the organisation’s vision.

    Research limitations/implications – This study hopes to broaden the understanding of the relationship between collective learning in organisations and organisational adaptation in times of crisis.

    Practical implications – This study can help leaders of social entrepreneurial organisations understand what changes are necessary to create a team that collectively learns.

    Originality/value – The data had the advantage of being gathered as a real-time process, and the researcher witnessed how the organisation achieved adaptation as it happened and not just through its members’ reflection of it as a past phenomenon.

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  • Machard, Anaïs
    et al.
    Salvati, Agnese
    P. Tootkaboni, Mamak
    Gaur, Abhishek
    Zou, Jiwei
    Wang, Liangzhu Leon
    Baba, Fuad
    Ge, Hua
    Bre, Facundo
    Bozonnet, Emmanuel
    Corrado, Vincenzo
    Luo, Xuan
    Levinson, Ronnen
    Lee, Sang Hoon
    Hong, Tianzhen
    Salles Olinger, Marcello
    Machado, Rayner Maurício e Silva
    da Guarda, Emeli Lalesca Aparecida
    Veiga, Rodolfo Kirch
    Lamberts, Roberto
    Afshari, Afshin
    Ramon, Delphine
    Ngoc Dung Ngo, Hoang
    Sengupta, Abantika
    Breesch, Hilde
    Heijmans, Nicolas
    Deltour, Jade
    Kuborn, Xavier
    Sayadi, Sana
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Qian, Bin
    Zhang, Chen
    Rahif, Ramin
    Attia, Shady
    Stern, Philipp
    Holzer, Peter
    Typical and extreme weather datasets for studying the resilience of buildings to climate change and heatwaves2024In: Scientific Data, E-ISSN 2052-4463, Vol. 11, no 1, article id 531Article in journal (Refereed)
    Abstract [en]

    We present unprecedented datasets of current and future projected weather files for building simulations in 15 major cities distributed across 10 climate zones worldwide. The datasets include ambient air temperature, relative humidity, atmospheric pressure, direct and diffuse solar irradiance, and wind speed at hourly resolution, which are essential climate elements needed to undertake building simulations. The datasets contain typical and extreme weather years in the EnergyPlus weather file (EPW) format and multiyear projections in comma-separated value (CSV) format for three periods: historical (2001–2020), future mid-term (2041–2060), and future long-term (2081–2100). The datasets were generated from projections of one regional climate model, which were bias-corrected using multiyear observational data for each city. The methodology used makes the datasets among the first to incorporate complex changes in the future climate for the frequency, duration, and magnitude of extreme temperatures. These datasets, created within the IEA EBC Annex 80 “Resilient Cooling for Buildings”, are ready to be used for different types of building adaptation and resilience studies to climate change and heatwaves.

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  • Garcia, Cesar
    et al.
    Universidad Nacional de Chimborazo (UNACH), Riobamba, Ecuador.
    Andrade Valle, Alexis Ivan
    Universidad Nacional de Chimborazo (UNACH), Riobamba, Ecuador; Universitat Politecnica de Valencia, Valencia, Spain.
    Silva Conde, Angel Alberto
    Universidad Nacional de Chimborazo (UNACH), Riobamba, Ecuador.
    Ulloa, Nestor
    Escuela Superior Politecnica de Chimborazo (ESPOCH), Riobamba, Ecuador.
    Bahrami, Alireza
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Onyelowe, Kennedy C.
    Michael Okpara University of Agriculture, Umudike, Nigeria; Michael Okpara University of Agriculture, Umudike, Nigeria.
    Ebid, Ahmed M.
    Future University in Egypt, New Cairo, Egypt.
    Hanandeh, Shadi
    Al-Balqa Applied University, As-Salt, Jordan.
    Predicting the impact of adding metakaolin on the splitting strength of concrete using ensemble ML classification and symbolic regression techniques –a comparative study2024In: Frontiers in Built Environment, E-ISSN 2297-3362, Vol. 10, article id 1395448Article in journal (Refereed)
    Abstract [en]

    The mechanical characteristics of concrete are crucial factors in structural design standards especially in concrete technology. Employing reliable prediction models for concrete’s mechanical properties can reduce the number of necessary laboratory trials, checks and experiments to obtain valuable representative design data, thus saving both time and resources. Metakaolin (MK) is commonly utilized as a supplementary replacement for Portland cement in sustainable concrete production due to its technical and environmental benefits towards net-zero goals of the United Nations Sustainable Development Goals (UNSDGs). In this research work, 204 data entries from concrete mixes produced with the addition of metakaolin (MK) were collected and analyzed using eight (8) ensemble machine learning tools and one (1) symbolic regression technique. The application of multiple machine learning protocols such as the ensemble group and the symbolic regression techniques have not been presented in any previous research work on the modeling of splitting tensile strength of MK mixed concrete. The data was partitioned and applied according to standard conditions. Lastly, some selected performance evaluation indices were used to test the models’ accuracy in predicting the splitting strength (Fsp) of the studied MK-mixed concrete. At the end, results show that the k-nearest neighbor (KNN) outperformed the other techniques in the ensemble group with the following indices; SSE of 4% and 1%, MAE of 0.1 and 0.2 MPa, MSE of 0, RMSE of 0.1 and 0.2 MPa, Error of 0.04% and 0.04%, Accuracy of 0.96 and 0.96 and R2 of 0.98 and 0.98 for the training and validation models, respectively. This is followed closely by the support vector machine (SVM) with the following indices; SSE of 7% and 3%, MAE of 0.2 and 0.2 MPa, MSE of 0.0 and 0.1 MPa, RMSE of 0.2 and 0.3 MPa, Error of 0.05% and 0.06%, Accuracy of 0.95 and 0.94, and R2 of 0.96 and 0.95, for the training and validation models, respectively. The third model in the superiority rank is the CN2 with the following performance indices; SSE of 15% and 4%, MAE of 0.2 and 0.2 MPa, MSE of 0.1 and 0.1 MPa, RMSE of 0.3 and 0.3 MPa, Error of 0.08% and 0.07%, Accuracy of 0.92 and 0.93 and R2 of 0.92 and 0.93, for the training and validation models, respectively. These models outperformed the models utilized on the MK-mixed concrete found in the literature, therefore are the better decisive modes for the prediction of the splitting strength (Fsp) of the studied MK-mixed concrete with 204 mix data entries. Conversely, the NB and SGD produced unacceptable model performances, however, this is true for the modeled database collected for the MK-mixed Fsp. The RSM model also produced superior performance with an accuracy of over 95% and adequate precision of more than 27. Overall, the KNN, SVM, CN2 and RSM have shown to possess the potential to predict the MK-mixed Fsp for structural concrete designs and production. 

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  • Public defence: 2024-06-14 13:00 Stora Jadwiga
    Mörtsell, Sara
    University of Gävle, Faculty of Education and Business Studies, Department of Educational sciences, Educational science. Umeå universitet, Pedagogiska institutionen.
    Maintaining teaching: exploring te(a)ch-abilities with actor-network theory2024Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The thesis investigates everyday teaching with digital technology during the Covid-19 pandemic in 2020 and 2021. The pandemic was one of the world’s largest disruptions to everyday education with both health and education at stake. With the pandemic control measures affecting upper secondary education in Sweden, gathering in the classroom cannot be taken for granted and digital technologies accelerated and intensified everyday practices. The aim is to explore the relation of teaching and digital technology. How can we understand the ways in which digital technology and teaching become jointly experimented with to cope with pandemic uncertainty?

    With an Actor-Network theory (ANT) approach, the thesis puts emphasis on how everyday teaching holds together at the pandemic intersection of routine and breakdown. The everyday teaching practices during the pandemic is an empirical focal point for inquiry into how they become enacted and, secondly, what the implications are for knowledge production when examining this novel educational practice with ANT’s relational materialism. To answer these questions, ethnographic methods are used with an upper secondary school in Sweden from May 2020 to June 2021. The fieldwork consists of empirical engagements in school visits, interviews, and online observations. In line with recent ANT scholarship, the methodological approach is articulated as a care-ful methodology. It implies tracing vulnerable and stable relations that enact sociomaterial practice and acknowledging cuts and becoming.

    The results show how a manifold of more-than-digital practices enact everyday teaching. The included studies in the thesis examine attendability and mundane rituals, lesson enactments of scheduling practices, and digital platforms that co-produce specific practices while obscuring others. Teaching in the pandemic challenges taken-for-granted notions of a rapid transition to distance and online teaching. By surfacing neglected aspects of everyday teaching with digital technology the thesis discusses how ‘digitalisation of teaching’ erases the local work of everyday teaching as an equipped practice. In conclusion, the proposal is made that maintaining teaching takes into account the materiality, abilities, care, and vulnerabilities that enact everyday teaching.

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  • Rashid, Farhan Lafta
    et al.
    Petroleum Engineering Department, College of Engineering, University of Kerbala, Karbala 56001, Iraq.
    Khalaf, Abbas Fadhil
    Petroleum Engineering Department, College of Engineering, University of Kerbala, Karbala 56001, Iraq.
    Ameen, Arman
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Al-Obaidi, Mudhar A.
    Technical Institute of Baquba, Middle Technical University, Baquba 32001, Iraq;Technical Instructor Training Institute, Middle Technical University, Baghdad 10074, Iraq.
    Investigation of Thermo-Hydraulics in a Lid-Driven Square Cavity with a Heated Hemispherical Obstacle at the Bottom2024In: Entropy, E-ISSN 1099-4300, Vol. 26, no 5, article id 408Article in journal (Refereed)
    Abstract [en]

    Lid-driven cavity (LDC) flow is a significant area of study in fluid mechanics due to its common occurrence in engineering challenges. However, using numerical simulations (ANSYS Fluent) to accurately predict fluid flow and mixed convective heat transfer features, incorporating both a moving top wall and a heated hemispherical obstruction at the bottom, has not yet been attempted. This study aims to numerically demonstrate forced convection in a lid-driven square cavity (LDSC) with a moving top wall and a heated hemispherical obstacle at the bottom. The cavity is filled with a Newtonian fluid and subjected to a specific set of velocities (5, 10, 15, and 20 m/s) at the moving wall. The finite volume method is used to solve the governing equations using the Boussinesq approximation and the parallel flow assumption. The impact of various cavity geometries, as well as the influence of the moving top wall on fluid flow and heat transfer within the cavity, are evaluated. The results of this study indicate that the movement of the wall significantly disrupts the flow field inside the cavity, promoting excellent mixing between the flow field below the moving wall and within the cavity. The static pressure exhibits fluctuations, with the highest value observed at the top of the cavity of 1 m width (adjacent to the moving wall) and the lowest at 0.6 m. Furthermore, dynamic pressure experiences a linear increase until reaching its peak at 0.7 m, followed by a steady decrease toward the moving wall. The velocity of the internal surface fluctuates unpredictably along its length while other parameters remain relatively stable.

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  • Sathvik, S.
    et al.
    Dayananda Sagar College of Engineering, Bengaluru, Karnataka 560111, India.
    Kumar, G. Shiva
    Dayananda Sagar College of Engineering, Bengaluru, Karnataka 560111, India.
    Bahrami, Alireza
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Nitin, G.C.
    Dayananda Sagar College of Engineering, Bengaluru, Karnataka 560111, India.
    Singh, Sumit Kumar
    Anton Paar India, Gurgaon, India.
    Althaqafi, Essam
    College of Engineering, King Khalid University, Abha 61421, Saudi Arabia.
    Özkılıç, Yasin Onuralp
    Necmettin Erbakan University, Konya, Turkey.
    Evaluation of asphalt binder and mixture properties utilizing fish scale powder as a biomodifier2024In: Case Studies in Construction Materials, ISSN 2214-5095, Vol. 20, article id e03238Article in journal (Refereed)
    Abstract [en]

    Fish represents an abundant and underutilized waste product from the fishing industry. This study investigated the effects of incorporating fish scale powder (FSP) at various dosages (3%, 6%, 9%, and 12%) on the properties of asphalt binder and mixtures. Conventional tests, viscosity, storage stability, Fourier transform infrared spectroscopy, and multiple stress creep recovery tests were conducted on the binder. Mix design, wheel tracking, indirect tensile strength, fatigue, and ultrasonic pulse velocity tests were evaluated for the asphalt mixtures. The results showed that FSP increased the binder’s stiffness and reduced the temperature susceptibility but compromised the low-temperature performance and workability regardless of the dosages. The storage stability test results demonstrated the improved high-temperature storage stability. In the mixtures, the permanent deformation resistance enhanced with increasing the FSP content, decreasing the rut depth from 4.3 mm for the control sample to 2.9 mm at 12% FSP. The moisture damage resistance, indicated by the tensile strength ratio, increased from 90% for the control sample to 94.1% at 12% FSP. However, the fatigue life decreased from 14010 cycles for the control sample to 11190 cycles at 12% FSP. The dynamic and elastic modulus values before conditioning increased with higher FSP dosages, and this increasing trend was also observed after conditioning, signifying greater stiffness retention and moisture resistance of the asphalt mixtures containing higher amounts of FSP. Numerically, the 6–9% FSP range offered the optimum balance, improving the rutting resistance by 18% and the moisture resistance by 3.2% compared to those of the control sample, while limiting the fatigue life to 12% and maintaining the workability. Overall, FSP has potential for use as an asphalt biomodifier by transforming an environmental liability into a value-added sustainable paving material.

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  • Ren, Honghao
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology. Department of Building Engineering, Energy Systems and Sustainability Science, Faculty of Engineering and Sustainable Development, University of Gävle, 801 76 Gävle, Sweden.
    Bahrami, Alireza
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Cehlin, Mathias
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Wallhagen, Marita
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Environmental Science. Department of Building Engineering, Energy Systems and Sustainability Science, Faculty of Engineering and Sustainable Development, University of Gävle, 801 76 Gävle, Sweden.
    Flexural Behavior of Cross-Laminated Timber Panels with Environmentally Friendly Timber Edge Connections2024In: Buildings, E-ISSN 2075-5309, Vol. 14, no 5, article id 1455Article in journal (Refereed)
    Abstract [en]

    As a sustainable construction material, timber is more promoted than steel, concrete, and aluminum nowadays. The building industry benefits from using timber based on several perspectives, including decarbonization, improved energy efficiency, and easier recycling and disposal processes. The cross-laminated timber (CLT) panel is one of the widely utilized engineered wood products in construction for floors, which is an ideal alternative option for replacing reinforced concrete. One single CLT panel has an outstanding flexural behavior. However, CLT cannot be extended independently without external connections, which are normally made of steel. This article proposes two innovative adhesive-free edge connections made of timber, the double surface (DS) and half-lapped (HL) connections. These connections were designed to connect two CLT panels along their weak direction. Parametric studies consisting of twenty models were conducted on the proposed edge connections to investigate the effects of different factors and the flexural behavior of CLT panels with these edge connections under a four-point bending test. Numerical simulations of all the models were done in the current study by using ABAQUS 2022. Furthermore, the employed material properties and other relevant inputs (VUSDFLD subroutines, time steps, meshes, etc.) of the numerical models were validated through existing experiments. The results demonstrated that the maximum and minimum load capacities among the studied models were 6.23 kN and 0.35 kN, respectively. The load–displacement responses, strain, stress, and defection distributions were collected and analyzed, as well as their failure modes. It was revealed that the CLT panels’ load capacity was distinctly improved due to the increment of the connectors’ number (55.05%) and horizontal length (80.81%), which also reinforced the stability. Based on the findings, it was indicated that adhesive-free timber connections could be used for CLT panels in buildings and replace traditional construction materials, having profound potential for improving buildings’ sustainability and energy efficiency.

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  • Public defence: 2024-06-14 09:00 12:108, Gävle
    Ameen, Arman
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Experimental and numerical study of corner impinging jet ventilation for an office environment2024Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    An effective ventilation system is an important component of a building’s service infrastructure. It serves the dual purpose of creating a comfortable and healthy indoor environment for occupants, thereby enhancing their well-being and productivity. However, the ventilation system is also a part of the building that uses a high amount of energy.

    The main objective of this study is to evaluate a novel implementation of the impinging jet ventilation system by placing the supply inlet at the corners of the space or room, rather than in the traditional mid-wall section. The focus of this study is to test and evaluate corner impinging jet ventilation in a medium-sized office environment within a building that requires moderate amount of heating and cooling.

    In the first part of this study (summer condition), the system is evaluated in an experimental environment, where it is compared against other systems such as displacement ventilation and mixing ventilation. The evaluated parameters indicates that corner impinging ventilation system performs better than mixing ventilation but show similar results to displacement ventilation in terms of airchange effectiveness. This experimental setup was also tested in winter condition and the results showed that the system was most effective during summertime compared to wintertime. In wintertime the results for the air change effectiveness were similar to those of a mixing system.

    In the second part, numerical simulations were utilized to delve deeper into the behaviour of the corner impinging jet ventilation system close to the floor surface. A numerical model was created and validated against experimental measurements. In this part, the spreading of the air jet across the room floor was examined, and its relation to various parameters such as inlet velocity, inlet shape and discharge height. Results indicated that diffuser geometries have almost no impact on velocity profile along the floor's centreline, jet spreading rate and maximum velocity decay. The results also showed a high degree of flexibility for the room size, between 25-100 m2 for which the results were applicable. The results also concluded that there was a noticeable confinement effect present and that the jet was able to travel far into the room.

    In the third part numerical simulations was used for validating and to create a model for an office room containing two office workstations. The office room was evaluated in terms of local thermal comfort, close to the sitting area. In addition, the indoor air quality was also examined. The results showed that corner impinging ventilation system performed better than conventional mixing ventilation system, especially when evaluating the indoor air quality in terms of mean age of air. This evaluation also took into account both outdoor summer and winter conditions, as well as different inlet surface areas. Different locations for the workstations were also evaluated with good results, except for placing the work-stations close to the inlets. Due to the system’s effectiveness of providing fresh air to the occupants, further analysis was made to try and reduce the air flowrate but keep the same indoor air quality level as an equivalent fully mixing ventilation system. By using this method, the study was able to demonstrate reduction in the energy use by reducing the air flowrate of the supply inlet. The study showed a possible reduction of the energy use by 7-9 % for outdoor temperatures ranging between -15 °C to 25 °C.

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  • Fahlstedt, Helena
    University of Gävle.
    Forskning pågar 2024: Akademin för hälsa och arbetsliv2024Report (Other academic)
    Abstract [sv]

    Verksamheten vid akademin för hälsa och arbetsliv utgör en kollegial och tvärvetenskaplig miljö som tar avstamp i människors olika livsvillkor och sammanhang med fokus på människan som individ, i grupper, organisationer och samhällen. Fysisk, psykisk och social hälsa utgör den gemensamma nämnaren. Utbildningen och forskningen kring dessa livsvillkor handlar om människors välbefinnande i en gynnsam ekologisk, ekonomisk och social miljö.

    Rapporten är ett sätt för Akademin att ge en överblick över den forskning och de projekt som i stunden pågår. Sammanställningen i sig kan göra att forskare kan finna gemensamma nämnare och därigenom bidra till framtida projekt men också visa den intresserade externa forskaren vad för forskning och vilka forskningsprojekt som bedrivs vid Akademin.

    Rapporten innehåller omkring ett hundratal projekt som svarar mot samhällsutmaningar inom hälsa och välfärd. Den kunskap som utvecklas genom vår forskning skapar goda förutsättningar för att vi ska kunna bidra till en positiv utveckling inom dessa områden. Ny kunskap kan göra skillnad!

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  • Klarare, A.
    et al.
    Department of Women’s and Children’s Health, Healthcare Sciences and e-Health, Uppsala University, Uppsala, Sweden;Department of Healthcare Sciences, Marie Cederschiöld University, Stockholm, Sweden.
    Vamstad, J.
    Centre for Civil Society Research, Marie Cederschiöld University, Stockholm, Sweden.
    Mattsson, E.
    Department of Women’s and Children’s Health, Healthcare Sciences and e-Health, Uppsala University, Uppsala, Sweden;Department of Healthcare Sciences, Marie Cederschiöld University, Stockholm, Sweden.
    Kneck, Å.
    Department of Healthcare Sciences, Marie Cederschiöld University, Stockholm, Sweden.
    Salzmann-Erikson, Martin
    University of Gävle, Faculty of Health and Occupational Studies, Department of Caring Science, Caring Science.
    Social rights in relation to digitalization, mobile phone, and internet use - experiences of women in homelessness: a qualitative study2024In: Critical Public Health, ISSN 0958-1596, E-ISSN 1469-3682, Vol. 34, no 1, p. 1-16Article in journal (Refereed)
    Abstract [en]

    Given the fact that women in homelessness face considerable health inequities, the question of how digitalization can be understood in relation to social rights and right to health surfaces. The objective of this qualitative interview study was to explore the use of mobile phones and internet for women experiencing homelessness. Women (n = 26) shared experiences of healthcare access by using a mobile phone or internet. Data were analyzed using NVivo software. The results are presented in two themes: Conditions and circumstances of having a mobile phone; and Structural and intrapersonal challenges affecting social rights. The results show that digitalization actively influenced everyday life for women experiencing homelessness. Whether women wanted it to or not, digitalization presents a line of demarcation for participation and inclusion or exclusion, in health- and social-care services.

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  • Huang, Bingzhang
    et al.
    Liuzhou Institute of Technology, Liuzhou 545004, China.
    Bahrami, Alireza
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Javed, Muhammad Faisal
    GIK Institute of Engineering Sciences and Technology, Topi, Swabi 23460, Pakistan.
    Azim, Iftikhar
    Government of Khyber Pakhtunkhwa, Peshawar 25000, Pakistan.
    Iqbal, Muhammad Ayyan
    Department of Civil Engineering, University of Engineering and Technology, Lahore 39161, Pakistan.
    Evolutionary Algorithms for Strength Prediction of Geopolymer Concrete2024In: Buildings, E-ISSN 2075-5309, Vol. 14, no 5, article id 1347Article in journal (Refereed)
    Abstract [en]

    Geopolymer concrete (GPC) serves as a sustainable substitute for conventional concrete by employing alternative cementitious materials such as fly ash (FA) instead of ordinary Portland cement (OPC), contributing to environmental and durability benefits. To increase the rate of utilization of FA in the construction industry, distinctive characteristics of two machine learning (ML) methods, namely, gene expression programming (GEP) and multi-expression programming (MEP), were utilized in this study to propose precise prediction models for the compressive strength and split tensile strength of GPC comprising FA as a binder. A comprehensive database was collated, which comprised 301 compressive strength and 96 split tensile strength results. Seven distinct input variables were employed for the modeling purpose, i.e., FA, sodium hydroxide, sodium silicate, water, superplasticizer, and fine and coarse aggregates contents. The performance of the developed models was assessed via numerous statistical metrics and absolute error plots. In addition, a parametric analysis of the finalized models was performed to validate the prediction ability and accuracy of the finalized models. The GEP-based prediction models exhibited better performance, accuracy, and generalization capability compared with the MEP-based models in this study. The GEP-based models demonstrated higher correlation coefficients (R) for predicting the compressive and split tensile strengths, with the values of 0.89 and 0.87, respectively, compared with the MEP-based models, which yielded the R values of 0.76 and 0.73, respectively. The mean absolute errors for the GEP- and MEP-based models for predicting the compressive strength were 5.09 MPa and 6.78 MPa, respectively, while those for the split tensile strengths were 0.42 MPa and 0.51 MPa, respectively. The finalized models offered simple mathematical formulations using the GEP and Python code-based formulations from MEP for predicting the compressive and tensile strengths of GPC. The developed models indicated practical application potential in optimizing geopolymer mix designs. This research work contributes to the ongoing efforts in advancing ML applications in the construction industry, highlighting the importance of sustainable materials for the future.

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  • Sahil, Mehran
    et al.
    Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi 23640, Pakistan.
    Bahrami, Alireza
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Waqas, Hafiz Ahmed
    Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi 23640, Pakistan.
    Amin, Fayiz
    Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi 23640, Pakistan.
    Mansoor Khan, Muhammad
    Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi 23640, Pakistan.
    Iqbal, Fahad
    Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, 23640, Topi, Pakistan.
    Fawad, Muhammad
    Silesian University of Technology, Poland.
    Najam, Fawad Ahmad
    University of British Columbia, Canada.
    Seismic performance evaluation of exterior reinforced concrete beam-column connections retrofitted with economical perforated steel haunches2024In: Results in Engineering (RINENG), ISSN 2590-1230, Vol. 22, article id 102179Article in journal (Refereed)
    Abstract [en]

    The exterior beam-column joint (BCJ) within reinforced concrete (RC) frame structures is acknowledged as a vulnerable component prone to seismic failure. This article proposes a practical and economical strengthening method for exterior BCJs using a perforated steel haunch system. This method is designed to mitigate damage in BCJs and improve the seismic performance of the structure. Employing finite element modeling (FEM) techniques, the study evaluates the impact of perforated steel haunches on the BCJs’ behavior and performance. The investigation involves creating nine distinct models, each representing a BCJ with a steel haunch system. These models include a control model without any perforations and eight variations with different levels of perforation (ranging from 10% to 50%) within the steel haunch system. Furthermore, the study analyzes the influence of perforation shapes on the connections’ performance, considering square, circular, hexagonal, and triangular shapes. The results reveal that utilizing a steel haunch without perforations significantly increases the load-carrying capacity of a BCJ by about 89%. Additionally, circular or square-shaped perforations, up to 30–35% within the steel haunch, effectively prevent the joints’ failure and promote the ductile behavior. These findings hold the potential to advance the design methodology for RC joints subjected to seismic loads, thereby enhancing the structural resilience in earthquake-prone regions.

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  • Wahlgren, Catarina
    et al.
    University of Gävle, Faculty of Education and Business Studies, Department of Educational sciences, Educational science.
    Günter, Katerina Pia
    Centre of Gender Research, Uppsala University, Uppsala, Sweden.
    Portraits of Swedish natureculture identity – entanglements of (gender) equity and integration in early childhood education2024In: Gender and Education, ISSN 0954-0253, E-ISSN 1360-0516Article in journal (Refereed)
    Abstract [en]

    Photographs of children are used on a daily basis in Swedish preschool practice. Although the preschool curriculum prescribes gender equality and celebration of diversity, photographs of indoor activities have shown to display a homogenous view of children and an emphasis on masculine-coded productions and accomplishments. This article examines 325 photographs of outdoor activities from Swedish preschools with diverse ethnic compositions. Our results reveal a Swedish natureculture identity that is more explicitly performed in the multi-ethnic preschool classes. Since ideals of gender equality and closeness to nature connect to the image of Swedishness, this can be understood as compensatory pedagogy. Moreover, the natureculture identity appears to be neutral in relation to ethnicity and gender, which risks rendering diversity invisible. However, the displayed neutrality is also possible to understand as working towards equity where conventionally feminine values such as care, empathym and sensitivity are underscored as desirable for everyone.

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  • Molin, Jonas
    et al.
    University of Gävle, Faculty of Education and Business Studies, Department of Business and Economic Studies, Business administration.
    Ahmadi, Zahra
    University of Gävle, Faculty of Education and Business Studies, Department of Business and Economic Studies, Business administration.
    The influence of efficiency pursuing on business streamlining 2.02024In: Journal of business & industrial marketing, ISSN 0885-8624, E-ISSN 2052-1189, Vol. 39, no 13, p. 96-107Article in journal (Refereed)
    Abstract [en]

    Purpose: The purpose of this study is to develop and validate the business streamlining (BS) model proposed in 2017. Design/methodology/approach: This study/paper develops and validates the qualitatively generated BS model, a conceptual model of service sourcing relationships, by testing it quantitatively. A survey was sent to chief exective officers, chief purchasing officers or facility managers in 764 private or public companies in Sweden with an annual turnover exceeding € 10m. The categories were tested and analyzed by means of factor analysis. Findings: The BS model for managing service sourcing processes was confirmed to be significant overall, meaning that it is applicable irrespective of service sourcing context. The efficiency pursuing (EP) was found to have an interlinking role that calls for a revision of the BS model. Furthermore, the four categories tended to load pairwise. Research limitations/implications: Although this cross-sectional study confirms the relevance of the BS model for managing service-sourcing processes, further studies should examine both the relative significance of its categories in different service-sourcing contexts and why the four main categories tend to pair. Practical implications: The results support that the model is flexible and adaptable to a wide range of service-sourcing circumstances. Irrespective of the relative complexity of facility management (FM) sourcing processes, the categories can be adapted to fit the service sourcing context. Thus, it can be used as a tool to analyze and facilitate strategic decision-making. Originality/value: The paper validates that the BS model can represent the dynamics of different service-sourcing processes, regardless of the complexity of the context.

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  • Qvarfordt, Anna
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational Health, Psychology and Sports Sciences, Sports Science.
    Svedsäter, Göran
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational Health, Psychology and Sports Sciences, Sports Science.
    Fagher, Kristina
    Department of Health Sciences, Rehabilitation Medicine Research Group, Lund University.
    Bjerkefors, Anna
    Department of Physiology, Nutrition and Biomechanics, The Swedish School of Sport and Health Sciences (GIH), Stockholm.
    Blomqvist, Sven
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational Health, Psychology and Sports Sciences, Sports Science.
    Para sport and anti-doping: a study of Swedish Para athletes' experiences and perceptions2024In: Frontiers in Sports and Active Living, E-ISSN 2624-9367, Vol. 6, article id 1375359Article in journal (Refereed)
    Abstract [en]

    Introduction: A well-functioning anti-doping system relies on being perceived by athletes as effective, fair, and practically feasible to implement. While research has highlighted the views of Olympic athletes on anti-doping over the past decade, the experiences and perceptions of Para athletes have not been extensively explored. The purpose of this study was to examine Swedish elite Para athletes' experiences and perceptions of the policy and practice of the anti-doping system.

    Methods: A quantitative cross-sectional approach was used, with a web survey elaborated from a survey with Olympic athletes adjusted for Para athletes with physical, visual, and intellectual impairments. The sample consisted of 66 active Para athletes competing at national or international level (response rate 71%). Data were analyzed using descriptive statistics and differences between subgroups were examined Fisher's exact test. Thematic analysis was employed to analyze open-ended questions.

    Results: Most of the respondents expressed a positive outlook on the anti-doping system, advocating for comprehensive efforts. A significant portion (35%) had not received anti-doping education, with those who did reporting increased confidence in avoiding unintentional doping. Despite their elite status, half of the respondents had not undergone doping control. Mistrust regarding the system's effectiveness and fairness was identified, with over half of the participants emphasizing the need for new technical solutions to enhance procedures specifically tailored for Para athletes.

    Discussion: The athletes in this study advocate for a Para sports-focused approach in the anti-doping system, emphasizing equal testing opportunities, procedural adjustments for independence and privacy, and increased access to education. The findings illuminate the unique conditions faced by athletes with impairments within the anti-doping system, offering valuable insights for policymaking in the development of anti-doping strategies tailored to Para athletes and their various impairments.

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  • Public defence: 2024-05-31 09:00 Stora Jadwigasalen,13:111, Gävle
    Högstedt, Denice
    University of Gävle, Faculty of Health and Occupational Studies, Department of Caring Science, Caring Science.
    Internationally Educated Nurses’ Inclusion in Swedish Working Life: The Recertification Process and the First Year Working as a Nurse in Sweden2024Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Aim: The overall aim was to examine facilitators and challenges towards and for an inclusive working life in Sweden for nurses educated in countries outside the EU/EEA and Switzerland, to examine and compare two paths to a Swedish nursing license – bridging program and validation – and to examine nurses’ perceived competence and well-being at work during the first year as nurses in Sweden. Methods: Data were collected through interviews and a longitudinal survey. This took place at three time points: the end of the licensure process, after three months, and after one year. Results: Both paths had been challenging and facilitating, albeit in different ways. The bridging program had been intensive, but also rewarding. The nurses had developed new knowledge, gained new relationships, improved their language and academic skills, and gained confidence to practice as a nurse in Sweden. The other path, through validation, had been a struggle due to uncertainty, loneliness, and considerable waiting. However, it was also facilitating because it enabled the nurses to work during the process. Support was important during recertification but was sometimes insufficient. At the end of recertification, no differences in self-rated competence, general self-efficacy, or thriving were found between those who had chosen the bridging program and those who had chosen validation. One year later, the choice of path to a nursing license was not related to the nurses’ perceived competence or well-being at work, however, current working conditions were. In addition, in interviews, previous education and working experiences were reported as facilitating factors during their first year as nurses in Sweden. Conclusions: Both paths to a Swedish nursing license were challenging but also facilitating and seemed to meet different needs. The choice of path did not determine how the nurses perceived their competence and well-being once practicing as a nurse in Sweden. Instead, previous education and working experiences and supportive working conditions were important factors.

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  • Grek, Åsa
    et al.
    Högskolan Dalarna.
    Hartwig, Fredrik
    University of Gävle, Faculty of Education and Business Studies, Department of Business and Economic Studies, Business administration.
    Dougherty, Mark
    Högskolan i Halmstad.
    An Inductive Approach to Quantitative Methodology – Application of Novel Penalising Models in a Case Study of Target Debt Level in Swedish Listed Companies2024In: Journal of Risk and Financial Management, E-ISSN 1911-8074, Vol. 17, no 5, article id 207Article in journal (Refereed)
    Abstract [en]

    This paper proposes a method for conducting quantitative inductive research on survey data when the variable of interest follows an ordinal distribution. A methodology based on novel and traditional penalising models is described. The main aim of the study is to pedagogically present the method utilising the new penalising methods in a new application. A case was employed to outline the methodology. The purpose of the case is to select explanatory variables correlated with the target debt level in Swedish-listed companies. 

    The survey respondents were matched with accounting information from the companies’ annual reports. However, missing data were present: to fully utilise penalising models, we employed classification and regression trees (CART)-based imputations by multiple imputations chained equations (MICE) to address this problem.

    The imputed data were subjected to six penalising models: grouped multinomial lasso, ungrouped multinomial lasso, parallel Element Linked Multinomial-Ordinal (ELMO), semi-parallel ELMO, nonparallel ELMO, and cumulative generalised monotone incremental forward stagewise (GMIFS). While the older models yielded several explanatory variables for the hypothesis formation process, the new models (ELMO and GMIFS) identified only one; the quick asset ratio. Subsequent testing revealed that this variable was the only statistically significant variable to affect the target debt level.

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  • Islam, Md. Zahidul
    et al.
    First Capital University of Bangladesh.
    Chowdhury, Mohammad Rocky Khan
    First Capital University of Bangladesh; Monash University, Melbourne, Australia.
    Kader, Manzur
    Karolinska institutet.
    Billah, Baki
    Monash University, Melbourne, Australia.
    Rashid, Mamunur
    University of Gävle, Faculty of Health and Occupational Studies, Department of Social Work, Criminology and Public Health Sciences, Public Health Science.
    Determinants of low birth weight and its effect on childhood health and nutritional outcomes in Bangladesh2024In: Journal of Health, Population and Nutrition, ISSN 1606-0997, E-ISSN 2072-1315, Vol. 43, article id 64Article in journal (Refereed)
    Abstract [en]

    Background: The high incidence of low birth weight (LBW) is associated with an increased risk of infant mortality, adverse pregnancy outcomes for mothers, and a decline in overall health and well-being. The current study aimed to identify the various determinants of LBW and its effect on adverse health and nutritional outcomes of children aged 0-23 months in Bangladesh.  

    Methods: Bangladesh Demography and Health Survey (BDHS) 2017-18 data was used. A chi-square test and multivariable logistic regression analysis were used to find out the associations between independent variables and outcomes (e.g., LBW, child illness and undernutrition).

    Results: The overall prevalence of LBW among was 16.3%. Mother with no formal education (AOR=2.64, 95% CI= 0.55-3.30, p= 0.01), female child (AOR=1.31, 95% CI= 1.04-1.65, p=0.023); and poorest economic status (AOR= 1.69, 95% CI= 1.13-2.51, p=0.010), were identified significant determinants of LBW. Of home environment and hygiene factors, unimproved toilet facilities (AOR= 1.38, 95% CI= 1.03-1.84, p= 0.030) had a significant effect on LBW. In addition, children born with LBW were more likely to suffer fever (AOR=1.26, 95% CI= 1.05-1.60, p= 0.050), stunting (AOR=2.42, 95% CI= 1.86-3.15, p= <0.001), wasting (AOR=1.47, 95% CI= 1.02-2.25 p= 0.049), and underweight (AOR=3.19, 95% CI= 2.40-4.23, p= <0.001). 

    Conclusion: One out of five children was LBW in Bangladesh. Maternal education, sex of child, wealth index, and toilet facilities had significant effects on LBW. In addition, LWB contributed to children’s poor health and nutritional outcomes. Enhancing maternal pregnancy, and child health outcomes necessitates policies addressing poverty, gender inequality, and social disparities. Key strategies include promoting regular prenatal care, early medical intervention, reproductive health education, and safe hygiene practices. To combat the negative impacts of LBW, a comprehensive strategy is vital, encompassing exclusive breastfeeding, nutritional support, growth monitoring, accessible healthcare, and caregiver education.

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  • Özkılıç, Yasin Onuralp
    et al.
    Necmettin Erbakan University, Konya 42000, Turkey.
    Althaqafi, Essam
    King Khalid University, 61421 Abha, Saudi Arabia.
    Bahrami, Alireza
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Aksoylu, Ceyhun
    Konya Technical University, 42075 Konya, Turkey.
    Karalar, Memduh
    Zonguldak Bulent Ecevit University, Zonguldak 67100, Turkey.
    Özdöner, Nebi
    Necmettin Erbakan University, Konya 42000, Turkey.
    Shcherban, Evgenii M.
    Don State Technical University, 344003 Rostov‑On‑Don, Russia.
    Stel’makh, Sergey A.
    Don State Technical University, Gagarin Sq. 1, 344003 Rostov‑On‑Don, Russia.
    Beskopylny, Alexey
    Don State Technical University, 344003 Rostov‑On‑Don, Russia.
    Thomas, Blessen Skariah
    National Institute of Technology Calicut, Kerala 673601, India.
    Influence of ceramic waste powder on shear performance of environmentally friendly reinforced concrete beams2024In: Scientific Reports, E-ISSN 2045-2322, Vol. 14, article id 10401Article in journal (Refereed)
    Abstract [en]

    This investigation considered the usability of ceramic waste powder (CWP) in altered quantities in reinforced concrete beams (RCBs). In this way, it was aimed to reduce the environmental impacts of concrete by using CWP as a raw material in RCBs. 12 small-scale shear RCBs with the dimensions of 100 × 150 × 1000 mm were tested in this study. The variations of stirrups spacing and CWP ratio were examined in these specimens. The percentages of CWP by weight utilized in RCBs were 10%, 20%, and 30%, and stirrups spacings were adopted as 270 mm, 200 mm, and 160 mm. At the end of the study, it was determined that more than 10% CWP additive negatively affected the RCBs’ compressive strength. The load-carrying capacity reduced between 30.3% and 59.4% when CWP increased from 0% to 30% as compared to RCB with stirrups spacing of 270 mm without CWP. However, compared to RCB with stirrups spacings of 200 mm and 160 mm without CWP, there were decreases in the load-carrying capacity as 21.4%–54.3% and 18.6%–54.6%, respectively. While the CWP ratio increased, the specimens with 160 mm, 200 mm, and 270 mm stirrups spacings obtained a lower maximum load value. However, with the increase of the CWP ratio in the specimens with 160 mm stirrups spacing, RCBs reached the maximum load-carrying capacity at an earlier displacement value. When stirrups spacing was selected as 270 mm, it was observed that the maximum load-carrying capacity of RCBs reached at a similar displacement value as the CWP ratio increased. Besides, it was resulted that the bending stiffness of RCBs reduced as the quantity of CWP enhanced. The bending stiffness decreased by 29.1% to 66.4% in the specimens with 270 mm stirrups spacing, 36.3% to 20.2% with 200 mm stirrups spacing, and 10.3% to 36.9% with 160 mm stirrups spacing. As an implication of the experiments, the use of CWP up to 10% in RCBs was realized as an economical and environmental approach and is suggested. There is some evidence to report that making use of CWP may be considered to be ecologically benign. This is due to the fact that reusing CWP may significantly reduce CO2 emissions, save energy, and reduce total power consumption. Furthermore, the experimental results were compared to the analytical calculations.

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  • Waqas, Hafiz Ahmed
    et al.
    Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi 23640, Pakistan.
    Bahrami, Alireza
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Amin, Fayiz
    Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi 23640, Pakistan.
    Sahil, Mehran
    Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi 23640, Pakistan.
    Saud Khan, Muhammad
    Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi 23640, Pakistan.
    Numerical Modeling and Performance Evaluation of Carbon Fiber-Reinforced Polymer-Strengthened Concrete Culverts against Water-Induced Corrosion2024In: Infrastructures, E-ISSN 2412-3811, Vol. 9, no 5, article id 82Article in journal (Refereed)
    Abstract [en]

    Culverts fulfill the vital function of safely channeling water beneath railway tracks, highways, and overpasses. They serve various purposes, including facilitating drainage in areas such as watercourses, drainage zones, and regions with restricted ground-bearing capacity. Precast reinforced concrete (RC) box culverts are a popular choice because they are strong, durable, rigid, and economical. However, culverts are prone to corrosion due to exposure to a range of environmental factors and aggressive chemicals. Therefore, enhancing the design and construction of this crucial infrastructure is imperative to effectively combat corrosion and to adhere to modern standards of reliability and affordability. In this study, carbon fiber-reinforced polymer (CFRP) was used to strengthen corroded culverts, with promising potential to improve safety and longevity in these structures. This study compared the behavior of corroded RC box culverts to CFRP-strengthened ones using the finite element method (FEM). It explored the impact of varying the damage thicknesses owing to corrosion, ranging from 0 mm to 20 mm, on the structural performance of the box culverts. The results showed that the CFRP model exhibited a substantial 25% increase in the capacity and reduced the damage compared to the reference model. Moreover, a parametric study was conducted for establishing a cost-effective design, in which numerous CFRP strip configurations were examined for a damaged-culvert model. The results indicated that a complete CFRP sheet was most effective for the maximum design capacity and repair effectiveness. The study’s outcomes provide valuable insights for professionals engaged in enhancing the strength of box culverts, aiming to increase the capacity, enhance the stability, and strengthen corroded culverts.

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  • Colding, Johan
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Environmental Science. The Beijer Institute of Ecological Economics, Royal Swedish Academy of Sciences.
    Nilsson, Caroline
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Environmental Science.
    Sjöberg, Stefan
    University of Gävle, Faculty of Health and Occupational Studies, Department of Social Work, Criminology and Public Health Sciences, Social Work.
    Smart Cities for All? Bridging Digital Divides for Socially Sustainable and Inclusive Cities2024In: Smart Cities, E-ISSN 2624-6511, Vol. 7, no 3, p. 1044-1059Article in journal (Refereed)
    Abstract [en]

    This paper aims to emphasize the need for enhancing inclusivity and accessibility within smart-city societies. It represents the first attempt to apply Amartya Sen’s capability approach by exploring the implications of digital divides for promoting inclusive and climate-friendly cities that prioritize well-being, equity, and societal participation. Sen’s framework recognizes individual variations in converting resources into valuable ‘functionings’, and herein emphasizes the importance of aligning personal, social, and environmental conversion factors for individuals to fully navigate, participate in, and enjoy the benefits provided by smart cities. Adopting the capability approach and employing a cross-disciplinary analysis of the scientific literature, the primary objective is to broaden understanding of how to improve inclusivity and accessibility within smart-city societies, with a specific focus on marginalized community members facing first- and second-level digital divides. This paper underscores the importance of adopting a systemic perspective on climate-smart city navigation and stresses the importance of establishing a unified governing body responsible for monitoring, evaluating, and enhancing smart-city functionality. The paper concludes by summarizing some policy recommendations to boost social inclusion and address climate change in smart cities, such as creating capability-enhancing institutions, safeguarding redundancy in public-choice options, empowering citizens, and leveraging academic knowledge in smart-city policy formulation.

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  • Bautista Gonzalez, Oscar
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Electronics. Department of Electronics, Mathematics and Sciences, University of Gävle, 80176 Gävle, Sweden.
    Rönnow, Daniel
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Electronics. Department of Electronics, Mathematics and Sciences, University of Gävle, 80176 Gävle, Sweden.
    Physical Modeling of a Water Hydraulic Proportional Cartridge Valve for a Digital Twin in a Hydraulic Press Machine2024In: Processes, ISSN 2227-9717, Vol. 12, no 4, article id 693Article in journal (Refereed)
    Abstract [en]

    Digital twins are an emerging technology that can be harnessed for the digitalization of the industry. Steel industry systems contain a large number of electro-hydraulic components as proportional valves. An input–output model for a water proportional cartridge valve was derived from physical modeling based on fluid mechanics, dynamics, and electrical principles. The valve is a two-stage valve with two two/two-way water proportional valves as the pilot stage and a marginally stable poppet-type cartridge valve as the main valve. To our knowledge, this is the first time that an input–output model was derived for a two-stage proportional cartridge valve with a marginally stable main valve. The orifice equation, which is based on Bernoulli principles, was approximated by a polynomial, which made the parameter estimation easier and modeling possible without measuring the pressure of the varying control volume, in contrast with previous studies of similar types of valves situated in the pilot stage part of the valve. This work complements previous studies of similar types of valves in two ways: (1) data were collected when the valve was operating in a closed loop and (2) data were collected when the valve was part of a press mill machine in a steel manufacturing plant. Model parameters were identified from data from these operating conditions. The parameters of the input–output model were estimated by convex optimization with physical constraints to overcome the problems caused by poor system excitation. For comparison, a simple linear model was derived and the least squares method was used for the parameter estimation. A thorough estimation of the parameters’ relative errors is presented. The model contains five parameters related to the design parameters of the valve. The modeled position output was in good agreement with experimental data for the training and test data. The model can be used for the real-time monitoring of the valve’s status by the model parameters. One of the model parameters varied linearly with the production cycles. Thus, the aging of the valve can be monitored.

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  • Public defence: 2024-06-03 09:15 12:108, Gävle
    Petrović, Bojana
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology. Department of Energy Technology and Construction Engineering, Dalarna University, Sweden; NORSUS (Norwegian Institute for Sustainability Research), Kråkerøy, Norway .
    Whole Life Carbon Assessment and Life Cycle Cost Analysis of a Single-family Building2024Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The building sector is responsible for 34% of final energy consumption and contributes to 37% of global CO2 emissions. In alignment with sustainability goals, the European Union has set a target to reduce CO2 emissions in the building sector by up to 90% by 2050. Consequently, there is a great need to examine the climate impact of buildings and adopt a comprehensive perspective using a whole life carbon assessment. The aim of the thesis was to examine greenhouse gas (GHG) emissions and costs throughout all life cycle stages, applying a whole life carbon assessment and life cycle cost analysis for a single-family building situated in a Nordic climate. Additionally, both positive (released) and negative GHG emissions were explored and documented, encompassing operational and embodied impacts. In the thesis, the life cycle assessment and the life cycle cost methods have been applied by following the “cradle-to-grave” life cycle perspective. The study includes an analysis of the reference building design and comparisons with improved building design. 

    The thesis findings highlight a substantial decrease in released GHG emissions with 23% reduction for the analyzed improved building design showing 5.2 kg CO2e/m2/y50 compared to the reference building design showing 6.7 kg CO2e/m2/y50. Moreover, incorporating biogenic carbon and the D module into the cradle-to-grave approach shows the lowest total GHG emissions, manifesting as negative values, -0.7 kg CO2e/m2/y50 for the improved building design. Embodied impact accounts for 79% and 72% of the total impact, while operational impact accounts for 21% and 28% for the reference and improved building designs. When analyzing all building materials, it is shown that an increased share of wooden building materials in the improved building design results in decreased released (positive) GHG emissions and increased negative GHG emissions. The results underscore the significance of using wood-based building materials due to their manufacturing process having lower GHG emissions compared to non-wood solutions. Considering the reference building design, when analyzing the building energy systems, it should be noted that the embodied GHG emissions from the production phase of solar PV panels are considerably higher when compared to emissions from the ventilation system and heat pump. To decrease the embodied GHG emissions during the production phase of solar PV panels, the manufacturing process should be done in countries with a larger share of renewable energy sources in the electricity grid. Moreover, recognizing building materials with low GHG emissions that are economically profitable during the early phases of building design and construction is essential for reducing long-term environmental and economic consequences. Additionally, considering the utilization of reusable building products over new ones could be seen as a winning strategy for mitigating the climate impact in the building sector and decreasing the use of natural resources and waste. 

    Considering the economic impact, it can be noted that the construction costs are greater than operational costs and end-of-life costs comparing all life cycle stages. Approximately 50% of the construction costs are labor costs, followed by investment costs for building materials, installations, and pre-construction costs. Analyzing the building products’ costs, it is important to note that selecting cross-laminated timber (CLT) for a foundation could lead to higher investment costs compared to concrete slabs. 

    In conclusion, the result of the thesis encompasses a whole life carbon assessment in buildings. It underscores the importance of revealing all carbon flows associated with single-family buildings. Finally, the thesis outlines the advantages of utilizing wood-based materials and reusable building products for building owners, contractors, designers, architects, consultants, and other decision-makers. It emphasizes the importance of considering both the environmental and economic aspects of buildings to attain a comprehensive understanding.

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  • Cananau, Iulian
    University of Gävle, Faculty of Education and Business Studies, Department of Humanities, English.
    “Partialist” and “universalist”: American exceptionalism in antebellum writing on national identity2024In: Orbis Litterarum, ISSN 0105-7510, E-ISSN 1600-0730Article in journal (Refereed)
    Abstract [en]

    In this article, I analyze six well-known antebellum essays on US national identity from the perspective of their engagement with the contemporary exceptionalist discourse. My focus is on their representations of the particular and the universal, whose paradoxical relationship lies at the core of all national exceptionalisms. I approach antebellum exceptionalism as part of the history in which the authors of these texts (Emerson, Fuller, Simms, Douglass, and Delany) lived their lives and to which they responded in different ways. The analysis shows how the universal–particular duality at the core of US exceptionalism is conceived and operates in these essays' discourses of American identity. A tentative conclusion is that whenever the universal dimension of American exceptionalism is enlarged or challenged by other universal criteria, the nationalist ideology loosens its grip; conversely, its presence is stronger when particularization occurs. Furthermore, the representations of the universal and the particular in these texts are discussed in relationship with certain aspects of US exceptionalism as a cultural phenomenon of antebellum history, namely, Manifest Destiny, cultural nationalism, the concept of civilization, and the growing tensions of slavery and racial discrimination in the free states.

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  • Khalaf, Abbas Fadhil
    et al.
    Petroleum Engineering Department, College of Engineering, University of Kerbala, Karbala 56001, Iraq.
    Rashid, Farhan Lafta
    Petroleum Engineering Department, College of Engineering, University of Kerbala, Karbala 56001, Iraq.
    Letif, Shaimaa Abdel
    Petroleum Engineering Department, College of Engineering, University of Kerbala, Karbala 56001, Iraq.
    Ameen, Arman
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Mohammed, Hayder I.
    Department of Cooling and Air Conditioning Engineering, Imam Ja’afar Al-Sadiq University, Baghdad 10011, Iraq.
    A Numerical Study of the Effect of Water Speed on the Melting Process of Phase Change Materials Inside a Vertical Cylindrical Container2024In: Applied Sciences, E-ISSN 2076-3417, Vol. 14, no 8, article id 3212Article in journal (Refereed)
    Abstract [en]

    The present work offers a thorough analysis of the impact of water velocity on phase change material (PCM) melting in a vertical cylindrical container. A detailed quantitative analysis uses sophisticated numerical techniques, namely the ANSYS/FLUENT 16 program, to clarify the complex relationship between enthalpy and porosity during the melting process. The experimental focus is on phase transition materials based on paraffin wax, particularly Rubitherm RT42. This study’s primary goal is to evaluate the effects of different water velocities (that is, at velocities of 0.01 m/s, 0.1 m/s, and 1 m/s) on the PCM’s melting behavior at a constant temperature of 333 K. This work intends to make a substantial contribution to the development of thermal energy storage systems by investigating new perspectives on PCM behavior under various flow circumstances. The study’s key findings highlight the possible ramifications for improving PCM-based thermal energy storage devices by revealing significant differences in melting rates and behavior that correlate to changes in water velocities. Future research is recommended to explore the impact of temperature variations, container geometries, and experimental validation to improve the accuracy and practicality of the results and to advance the creation of sustainable and effective energy storage solutions.

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