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The global salinity gradient power (SGP) potential is between 1650 - 2000 TWH/a and can be converted by mixing two solutions with different salinities. The harnessing of SGP for conversion into power can be accomplished by means of pressure retarded osmosis (PRO) and reverse electrodialysis (RED). PRO and RED are membrane-based technologies and have different working principles. PRO uses a semipermeable membrane to seperate a concentrated salt solution from a diluted solution. The diluted solution flows through the semipermeable membrane towards the concentrated solution, which increases the pressure within the concentrated solution chamber. The pressure is balanced by a turbine and electricity is generated. RED uses the transport of ions through cation and anion exchange membranes. The chambers between the membranes are alternately filled with a concentrated and diluted solution. The salinity gradient difference is the driving force in transporting ions that results in an electric potential, which is then converted to electricity. The comparison shows that there are two different fields of application for PRO and RED. PRO is especially suitable at extracting salinity energy from large concentration differences. In contrast, RED are not effect by increasing concentration differences. So PRO are supposed to focus on applications with brines or waste water and RED on applications with river water and seawater. Moreover, just a few measured values from processes under real conditions are available, which makes it difficult to compare PRO and RED.
Adhärenz digitaler Interventionen im Gesundheitswesen: Definitionen, Methoden und offene Fragen
(2021)
AbstractMany digital interventions rely on the participation of their users to have a positive impact. In various areas it can be observed that the use of digital interventions is often reduced or fully discontinued by the users after a short period of time. This is seen as one of the main factors that can limit the effectiveness of digital interventions. In this context, the concept of adherence to digital interventions is becoming increasingly important. Adherence to digital interventions is roughly defined as “the degree to which the user followed the program as it was designed,” which can also be paraphrased as “intended use” or “use as it is designed.” However, both the theoretical–conceptual and practical discussions regarding adherence to digital interventions still receive too little attention.The aim of this narrative review article is to shed more light on the concept of adherence to digital interventions and to distinguish it from related concepts. It also discusses the methods and metrics that can be used to operationalize adherence and the predictors that positively influence adherence. Finally, needs for action to better address adherence are considered critically.
As a salutogenic concept, “consumption corridors” aims to support what is necessary for sustainable wellbeing to be achieved in relation to the Earth system, with a deep consideration for justice and equity. Living in consumption corridors is a representation of everyday life whereby people live within limits, so that all people – now and in the future – can access what is needed to live a good life. In this special issue, a series of scholars and practitioners have come together to further develop the concept, engage with its ethodological implications, and relate it to consumption domains and policy implications. We begin by introducing how the concept emerged, in relation to the complexity of grappling with the societal transformations required for achieving more sustainable forms of consumption. We then present the different contributions, which demonstrate the importance of considering both maximum and minimum consumption standards, the relevance of human-need theories, as well as the difference between achieving wellbeing and the means necessary for doing so. We conclude by opening up to areas that merit further deliberation: how to relate consumption corridors to everyday-life dynamics, but also to the critical question of power relations at play in implementing consumption corridors.
Experimental results are presented of a test of the theory of local turbulent heat transfer measurements proposed by Mocikat and Herwig in 2007. A miniaturized multi-layer heat transfer sensor was developed and employed in this study. The new heat transfer sensor was designed to work in air and liquids, and this capability enabled the simultaneous investigation of different Prandtl numbers. Two basic configurations, namely the flow past a blunt plate and the flow past an inclined square cylinder, were investigated in test sections of wind and water tunnels. Convective heat transfer coefficients were obtained through conventional testing (i.e., employing thoroughly heated test objects) and using the new miniaturized sensor approach (i.e., utilizing cold test objects without heating). The main prediction of the Mocikat-Herwig theory that a specific thermal adjustment coefficient of the employed actual miniaturized heat transfer sensor should exist in the fully turbulent flow regime was proven for developed two-dimensional flow. The observed effect of the Prandtl number on this coefficient was in good agreement with the prediction of the asymptotic expansion method. The square cylinder results indicated the inherent limits of the local turbulent heat transfer measurement approach, as suggested by Mocikat and Herwig.
Assessment of noise mitigation measures during pile driving of larger offshore wind foundations
(2021)
Wind energy is an important source of electricity generation, but the construction of offshore wind foundations causes high underwater sound pressure, harming marine life. In this context limiting values for underwater noise emissions were set to protect the marine flora and fauna. Therefore, noise mitigation measures during pile driving are mandatory to comply with these limits. Current development in the wind industry lead to increasing wind turbine sizes, requiring a larger pile diameter, which leads to higher underwater noise emissions. As a result, the state of the art noise mitigation systems might not be sufficient and a combination of different technologies is necessary. This article focuses on the issue of noise mitigation during pile driving with respect to large pile sizes. First, the most tested and proven noise mitigation techniques (big bubble curtain, hydro sound damper, and IHC-noise mitigation system) are described, following an analysis of noise reduction measurements in applications at different offshore wind farm projects. In the end the suitability of current noise mitigation systems for large monopiles is evaluated, regarding their effectiveness and practicability.
Consumption Corridors: Living a Good Life within Sustainable Limits
explores how to enhance peoples’ chances to live a good life in a world of ecological and social limits.
Rejecting familiar recitations of problems of ecological decline
and planetary boundaries, this compact book instead offers a spirited explication of what everyone desires: a good life. Fundamental
concepts of the good life are explained and explored, as are forces
that threaten the good life for all. The remedy, says the book’s seven
international authors, lies with the concept of consumption corridors, enabled by mechanisms of citizen engagement and deliberative
democracy.
Across fve concise chapters, readers are invited into conversation about how wellbeing can be enriched by social change that joins
“needs satisfaction” with consumerist restraint, social justice, and
environmental sustainability. In this endeavour, lower limits of consumption that ensure minimal needs satisfaction for all are important, and enjoy ample precedent. But upper limits to consumption,
argue the authors, are equally essential, and attainable, especially in those domains where limits enhance rather than undermine essential
freedoms.
Originally this article was supposed to be a comparison between the technological differences of bottom-fixed offshore wind turbines (BOWT) and floating offshore wind turbines (FOWT). However, several authors already contributed to this topic and came to the conclusion that the higher levelized costs of energy (LCOE) prevent FOWTs from successfully entering the energy market. Multiple sources seem to agree on this conclusion but often do not provide the reader with further information regarding the LCOE. This is the reason why this article understands itself as an in depth cost comparison between BOWTs and FOWTs. For this purpose, individual LCOE are calculated for the upcoming FOWT technologies such as spar-buoy (SPAR), tension-leg platform (TLP) and semi-submersible platform (semi-sub) as well as conventional BOWTs using the wind turbines hours of full utilization (HOFU). The resulting functions are visualized graphically in order to determine break-even points between BOWTs and FOWTs. Finally, a sensitivity analysis is carried out to determine the influence of the weighted average costs of capital (WACC).
This paper presents a seminar concept for the development of communication competence in pre-service vocational education teachers with the aid of video annotations, feedback, and peer microteaching. The seminar is offered within a teacher training program for students taking a master’s degree (MEd) in vocational education at the FH Münster University of Applied Sciences, Germany, and has been conducted three times. The advantages of the seminar concept are manifold. On the one hand, we create a learning environment in which students individually prepare and conduct five peer microteaching lessons in a row and receive prompt and constructive peer feedback on every performance. On the other hand, the quality of feedback improves so that our students are professional feedback providers by the end of the seminar. The provision of teacher feedback alone does not help our students become successful feedback providers. Nor, given the resources available at the university, is it a realistic alternative in terms of time constraints. In addition, due to recordings, the students gain a better insight into their teaching skills since their lessons can be observed and approached from an outside perspective.