12 research outputs found
Integrated Modeling of Offshore Wind Turbines
No full textIn order for the offshore wind industry to be competitive, the cost has to be driven down. One of the major factors that contribute to the overall cost is the over-dimensioning of the substructure. The response of the structure under various loading conditions can provide valuable insight in the design phase so as to provide a structural design that is cost effective yet reliable, and can withstand the loads that are considered to act on the structure.The objective of the present thesis is the development of a 1D finite element model, that allows for a dynamic analysis of an offshore wind turbine under the combined actions of wind and wave or wind and ice. For this purpose, different models have been combined and improved or extended. Through this model the importance of accounting for non-linear and breaking waves, the effect of the kinematic stretching on the response and the manner in which the misalignment of the load affects the response can be investigated.A detailed design of the NREL-5MW offshore wind turbine supported by a monopile is subjected to wind, wave and ice action. The aerodynamic action is evaluated through a model valid for the above rated regime when pitch control is active, using a turbulent wind signal resulting from the Kaimal spectrum. The hydrodynamic action is calculated either with the Morison equation or the MacCamy and Fuchs equation with the use of either linear or nonlinear water particle kinematics. An approach towards the calculation of the load from a breaking wave is considered accounting for the wave skewness and asymmetry during such an event. The ice action is calculated through a model that evaluates the force while in the crushing regime. The soil is represented with linear soil springs.The structure’s response is investigated for all the loads separately at first. The next step is the combined analysis. Aligned and misaligned cases are considered. Results show that wind load is dominating the response in the aligned and misaligned wind and wave case regardless of the method used to calculate the hydrodynamic load in the case of a small wave height. In the case of a larger wave height, using Stokes theory and the Morison equation, the hydrodynamic load is contributing to the resulting response. Concerning the ice loading, the intermittent crushing and the continuous brittle crushing regimes occur for the turbine. The response to the combined wind and ice action appears to be affected by both loads in all examined cases.Offshore and Dredging Engineerin
Correction: The Role of Attachment Styles on Quality of Life and Distress Among Early-Stage Female Breast Cancer Patients: A Systematic Review (Journal of Clinical Psychology in Medical Settings, (2023), 10.1007/s10880-023-09940-w)
No full textDue to an oversight by this article’s authors, the orders of authors’ first and last names are given incorrectly in the original publication. The authors’ names should be listed as follows: Spyridoula Karveli, Petros Galanis, EiriniMarina Mitropoulou, Evangelos Karademas, & Christos Markopoulos. Likewise, the citation should be as follows: Karveli, S., Galanis, P., Mitropoulou, E. M., Karademas, E., & Markopoulos, C. (2023). The role of attachment styles on quality of life and distress among early-stage female breast cancer patients: A systematic review. Journal of Clinical Psychology in Medical Settings. https:// doi. org/ 10. 1007/ s10880- 023- 09940-w. © 2023 The Author(s)
EMOTIONAL LABOUR IN A BUREAUCRATIC MEDIA CONTEXT ON HR - A study on emotional labour of academic and administrative employees at Greek universities about mobility scheme during the financial crisis
No full textIn recent years, emotions in the workplace have become a topic of interest in management; academics, researchers and authors are becoming interested in the topic of emotions in an organisation. One crucial topic of discussion among the HR community is the experience of unpleasant events which generates negative emotions. This paper will explore how the academic and the administrative staff of two Greek universities affected emotionally because of the mass lay-offs of administrative staff. Eight questionnaires were answered by four members of the Foundation Board of National and Kapodistrian University of Athens (UOA) and four members of the Administrative Staff Department of Aristotle University of Thessaloniki. Moreover, the thesis analyses and describes how the media covered the topic. The study concentrated on three well-known Greek newspapers in their coverage of the lay-offs actions in Greece during the last four months in 2013. The author used a qualitative method to analyse the collected questionnaires. The outcome is that the academic and administrative staff had negative emotions regarding their bureaucratic role in the organisations. Sadness, stress, and disappointment are the main emotions of the academic community. The news articles seemed to comprehend the governmental announcements in order to preserve the common good
Διδάσκοντας το χιούμορ στη δεύτερη γλώσσα: μία εναλλακτική προσέγγιση στα πλαίσια του κριτικού γραμματισμού
No full textΣτόχος της παρούσας μελέτης αποτελεί η διευρεύνηση του γλωσσικού χιούμορ, των χρήσεων και των λειτουργιών του, η προσέγγισή του ως κοινωνιογλωσσικού φαινομένου, καθώς και η πρόταση ένταξής του στη διδασκαλία της ελληνικής ως δεύτερης(Γ2)/ξένης γλώσσας με βασικά οφέλη την καλλιέργεια κοινωνιοπραγματολογικής και κοινωνιοπολιτισμικής ικανότητας, καθώς και δυνατότητας συγκρότησης κοινωνικών ταυτοτήτων των αλλόγλωσσων μαθητών/τριών.The aim of this study is the exploration of linguistic humor, its uses, and its functions, its approach as a sociolinguistic phenomenon, as well as the proposal of humor' s integration in educational spaces of greek as a second language. In this study, the author highlight two basic humor' s benefits in second language teaching and learning; the cultivation of socio-pragmatic and socio-cultural competence, as well as second learners' ability to construct through humorous interaction their social identities
Pure threshold strategies for a two-node tandem network under partial information
No full textIn a two node tandem network, customers decide to join or balk by maximizing a given profit function whose costs are proportional to the sojourn time they spend at each queue. Assuming that their choicesare taken without knowing the complete state of the system, we show that a pure threshold equilibrium policy exists. In particular we analyze the case when the partial information consists in informing the arrival customers of the total number of users in the network.The research of the first author is partially supported by the
Spanish Ministry of Education and Science Grants MTM2013-42104-P (FEDER funds), MTM2010-16519 and RYC-2009-0467
An overview on the occurrence, fate and human risks of Bisphenol‐A (BPA) present in plastic materials, components and products (MCPs)
No full textJohn Hahladakis ORCID iD: 0000-0002-8776-6345; Eleni Iacovidou ORCID: 0000-0001-6841-0995; Spyridoula Gerassimidou ORCID: 0000-0003-3529-5761. Data availability statement: Data, associated metadata, and calculation tools are available from corresponding author John N. Hahladakis ([email protected], [email protected]).With over 95% of bisphenol-A (BPA) used in the production of polycarbonate (PC) and epoxy resins, termed here as BPA-based plastic materials, components, and products (MCPs), an investigation of human exposure to BPA over the whole lifecycle of BPA-based plastic MCPs is necessary. This mini-review unpacks the implications arising from the long-term human exposure to BPA and its potential accumulation across the lifecycle of BPA-based plastics (production, use, and management). This investigation is timely and necessary in promoting a sustainable circular economy model. Restrictions of BPA in the form of bans and safety standards are often specific to products, while safety limits rely on traditional toxicological and biomonitoring methods that may underestimate human health implications and therefore the “safety” of BPA exposure. Controversies in regards to the: (a) dose–response curves; (b) the complexity of sources, release mechanisms, and pathways of exposure; and/or (c) the quality and reliability of toxicological studies, appear to currently stifle progress toward the regulation of BPA-based plastic MCPs. Due to the abundance of BPA in our MCPs production, consumption, and management systems, there is partial and inadequate evidence on the contribution of BPA-based plastic MCPs to human exposure to BPA. Yet, the production, use, and end-of-life management of plastic MCPs constitute the most critical BPA source and potential exposure pathways that require further investigation. Active collaboration among risk assessors, government, policy-makers, and researchers is needed to explore the impacts of BPA in the long term and introduce restrictions to BPA-based MCPs.There are no funders to report for this submission
Instructional Message Design: Theory, Research, and Practice (Volume 2)
No full textMessage design is all around us, from the presentations we see in meetings and classes, to the instructions that come with our latest tech gadgets, to multi-million-dollar training simulations. In short, instructional message design is the real-world application of instructional and learning theories to design the tools and technologies used to communicate and effectively convey information. This field of study pulls from many applied sciences including cognitive psychology, industrial design, graphic design, instructional design, information technology, and human performance technology to name just a few. In this book we will visit several foundational theories that guide our research, look at different real-world applications, and begin to discuss directions for future best practice. For instance, cognitive load and multimedia learning theories provide best practice, virtual reality and simulations are only a few of the multitude of applications. Special needs learners and designing for online, e-learning, and web conferencing are only some of many applied areas where effective message design can improve outcomes. Studying effective instructional message design tools and techniques has and will continue to be a critical aspect of the overall instructional design process. Hopefully, this book will serve as an introduction to these topics and inspire your curiosity to explore further
Recent Advancements in the Atopic Dermatitis Mechanism
No full textAtopic dermatitis (AD) is a recurrent, chronic, inflammatory, itchy skin disorder that affects up to 20% of the pediatric population and 10% of the adult population worldwide. Onset typically occurs early in life, and although cardinal disease features are similar across all ages, different age groups and ethnicities present distinct clinical characteristics. The disease imposes a significant burden in all health-related quality of life domains, both in children and adults, and a substantial economic cost both at individual and national levels. The pathophysiology of AD includes a complex and multifaceted interplay between the impaired dysfunctional epidermal barrier, genetic predisposition, and environmental contributors, such as chemical and/or biological pollutants and allergens, in the context of dysregulated TH2 and TH17 skewed immune response. Regarding the genetic component, the loss of function mutations encoding structural proteins such as filaggrin, a fundamental epidermal protein, and the more recently identified variations in the epidermal differentiation complex are well-established determinants resulting in an impaired skin barrier in AD. More recently, epigenetic factors have facilitated AD development, including the dysbiotic skin microbiome and the effect of the external exposome, combined with dietary disorders. Notably, the interleukin (IL)-31 network, comprising several cell types, including macrophages, basophils, and the generated cytokines involved in the pathogenesis of itch in AD, has recently been explored. Unraveling the specific AD endotypes, highlighting the implicated molecular pathogenetic mechanisms of clinically relevant AD phenotypes, has emerged as a crucial step toward targeted therapies for personalized treatment in AD patients. This review aims to present state-of-the-art knowledge regarding the multifactorial and interactive pathophysiological mechanisms in AD. Copyright: © 2024 The Author(s)
Enhanced protein secretion in reduced genome strains of Streptomyces lividans
No full textHamed MB, Busche T, Simoens K, et al. Enhanced protein secretion in reduced genome strains of Streptomyces lividans. Microbial Cell Factories . 2024;23(1): 13.BACKGROUND: S. lividans TK24 is a popular host for the production of small molecules and the secretion of heterologous protein. Within its large genome, twenty-nine non-essential clusters direct the biosynthesis of secondary metabolites. We had previously constructed ten chassis strains, carrying deletions in various combinations of specialized metabolites biosynthetic clusters, such as those of the blue actinorhodin (act), the calcium-dependent antibiotic (cda), the undecylprodigiosin (red), the coelimycin A (cpk) and the melanin (mel) clusters, as well as the genes hrdD, encoding a non-essential sigma factor, and matAB, a locus affecting mycelial aggregation. Genome reduction was aimed at reducing carbon flow toward specialized metabolite biosynthesis to optimize the production of secreted heterologous protein.; RESULTS: Two of these S. lividans TK24 derived chassis strains showed~15% reduction in biomass yield, 2-fold increase of their total native secretome mass yield and enhanced abundance of several secreted proteins compared to the parental strain. RNAseq and proteomic analysis of the secretome suggested that genome reduction led to cell wall and oxidative stresses and was accompanied by the up-regulation of secretory chaperones and of secDF, a Sec-pathway component. Interestingly, the amount of the secreted heterologous proteins mRFP and mTNFalpha, by one of these strains, was 12 and 70% higher, respectively, than that secreted by the parental strain.; CONCLUSION: The current study described a strategy to construct chassis strains with enhanced secretory abilities and proposed a model linking the deletion of specialized metabolite biosynthetic clusters to improved production of secreted heterologous proteins. © 2023. The Author(s)
Development of an integrated sustainability matrix to depict challenges and trade-offs of introducing bio-based plastics in the food packaging value chain
No full textCopyright 2020 The Author(s). As global plastic pollution is gaining increased attention, the use of bio-based plastics, especially in the food packaging sector, is growing in popularity. While this move is regarded as a solution to plastic pollution, it may shift or create detrimental impacts elsewhere in the production, consumption, management system, a possibility that is underexplored. The aim of the present study is to identify the potential challenges and trade-offs associated with the introduction of bio-based plastics in the food packaging industry, and highlight issues relevant to policy and decision-making processes. We employ a whole system approach to review the literature and assess holistically the performance of bio-based plastics, which looks at the entire lifecycle of bio-based plastic packaging (i.e. production, consumption, management) and considers wider aspects in the environmental, economic, social and technical sustainability domains. Based on our findings, we developed, and present herein, a sustainability decision matrix, a novel guiding tool, which can provide important insights into the potential impacts of the introduction of larger amount of bio-based plastic food packaging in the future and support decision-making processes. In conclusion, our preliminary high-level assessment of the bio-based plastics production, use and management system clearly reveals a number of blind-spots across the entire system that are currently ignored by the use of single-dimensional approaches. This highlights that the sustainability assessment of specific bio-based polymers requires thorough and further research that takes into account the type of feedstock, infrastructure availability, and interactions between sustainability domains, to ensure that the substitution of petrochemical-based plastics with bio-based alternatives in food packaging sector will not lead to unintended consequences
