• Energy Research
• Research Council of Finland close
• EC|H2020 close

Molecular dynamics (MD) computer simulations are used routinely to compute atomistic trajectories of complex systems. Systems are simulated in various ensembles, depending on the experimental conditions one aims to mimic. While constant energy, temperature, volume, and pressure are rather straightforward to model, pH, which is an equally important parameter in experiments, is more difficult to account for in simulations. Although a constant pH algorithm based on the $\lambda$-dynamics approach by Brooks and co-workers was implemented in a fork of the GROMACS molecular dynamics program, uptake has been rather limited, presumably due to the poor scaling of that code with respect to the number of titratable sites. To overcome this limitation, we implemented an alternative scheme for interpolating the Hamiltonians of the protonation states that makes the constant pH molecular dynamics simulations almost as fast as a normal MD simulation with GROMACS. In addition, we implemented a simpler scheme, called multisite representation, for modeling side chains with multiple titratable sites, such as imidazole rings. This scheme, which is based on constraining the sum of the $\lambda$-coordinates, not only reduces the complexity associated with parameterizing the intra-molecular interactions between the sites, but is also easily extendable to other molecules with multiple titratable sites. With the combination of a more efficient interpolation scheme and multisite representation of titratable groups, we anticipate a rapid uptake of constant pH molecular dynamics simulations within the GROMACS user community.

Abstract Breakthrough alternative technologies are urgently required to alleviate the critical need to decarbonise our energy supply. We showcase non-conventional approaches to battery and solar energy conversion and storage (ECS) system designs that harness key attributes of immiscible electrolyte solutions, especially the membraneless separation of redox active species and ability to electrify certain liquid–liquid interfaces. We critically evaluate the recent development of membraneless redox flow batteries based on biphasic systems, where one redox couple is confined to an immiscible ionic liquid or organic solvent phase, and the other couple to an aqueous phase. Common to all solar ECS devices are the abilities to harvest light, leading to photo-induced charge carrier separation, and separate the products of the photo-reaction, minimising recombination. We summarise recent progress towards achieving this accepted solar ECS design using immiscible electrolyte solutions in photo-ionic cells, to generate redox fuels, and biphasic “batch” water splitting, to generate solar fuels.

A double-null configuration is being considered for the EU-DEMO, due to its potential benefits for power exhaust arising from the use of two active divertors and magnetically disconnected low- and high-field sides. Using systematic parameter scans in fluid simulations, we have investigated the divertor power exhaust in the EU-DEMO in a connected double-null configuration, and compared the edge plasma properties to those obtained in a single-null configuration under detached conditions anticipated for reactor operation. Neglecting drift effects and kinetic behaviour of the neutrals, no clear benefits of the double-null configuration could yet be identified for the radiation pattern and power mitigation on open field lines. Future work should address the aforementioned physics as well as the effect of the additional X-point on core radiation.

Forest canopies buffer macroclimatic temperature fluctuations. However, we do not know if and how the capacity of canopies to buffer understorey temperature will change with accelerating climate change. Here we map the difference (offset) between temperatures inside and outside forests in the recent past and project these into the future in boreal, temperate and tropical forests. Using linear mixed-effect models, we combined a global database of 714 paired time series of temperatures (mean, minimum and maximum) measured inside forests vs. in nearby open habitats with maps of macroclimate, topography and forest cover to hindcast past (1970-2000) and to project future (2060-2080) temperature differences between free-air temperatures and sub-canopy microclimates. For all tested future climate scenarios, we project that the difference between maximum temperatures inside and outside forests across the globe will increase (i.e. result in stronger cooling in forests), on average during 2060-2080, by 0.27 ± 0.16 °C (RCP2.6) and 0.60 ± 0.14 °C (RCP8.5) due to macroclimate changes. This suggests that extremely hot temperatures under forest canopies will, on average, warm less than outside forests as macroclimate warms. This knowledge is of utmost importance as it suggests that forest microclimates will warm at a slower rate than non-forested areas, assuming that forest cover is maintained. Species adapted to colder growing conditions may thus find shelter and survive longer than anticipated at a given forest site. This highlights the potential role of forests as a whole as microrefugia for biodiversity under future climate change.

Este documento proporciona una encuesta multidisciplinaria única de soluciones independientes para el acceso al agua limpia y sostenible en África y propone una arquitectura de tres segmentos, compuesta por una unidad de desinfección de agua basada en UV-LED, una batería de energía solar y un sistema de posicionamiento inalámbrico. Además, nuestro documento también proporciona resultados instantáneos iniciales de los tres segmentos de la arquitectura propuesta, así como dos ejemplos del análisis del agua y los resultados basados en la encuesta del usuario recopilados en Togo, África. Creemos que las características de nuestro sistema previsto, como la larga duración de la batería, el bajo costo de mantenimiento, la capacidad de aumentar significativamente la calidad y desinfectar al menos 1,5 l/min de agua y la capacidad de ofrecer posicionamiento inalámbrico sin la necesidad de acceder a una red celular o WiFi, para anotar con precisión las fuentes de agua, la localización de sistemas de desinfección extraviados o perdidos y las capacidades de posicionamiento independiente del usuario, son características atractivas para mejorar la calidad de vida de las personas con acceso limitado al agua potable o al agua que cumple con los criterios internacionales de calidad. Cet article fournit une enquête multidisciplinaire unique sur les solutions autonomes pour un accès à l'eau propre et durable en Afrique et propose une architecture à trois segments, composée d'une unité de désinfection de l'eau à base d'UV-LED, d'une batterie solaire et d'un système de positionnement sans fil. En outre, notre article fournit également des résultats instantanés initiaux des trois segments de l'architecture proposée, ainsi que deux exemples d'analyse de l'eau et de résultats d'enquête basés sur les utilisateurs collectés au Togo, en Afrique. Nous pensons que les caractéristiques de notre système envisagé, telles que la longue durée de vie de la batterie, le faible coût de maintenance, la capacité d'augmenter considérablement la qualité et de désinfecter au moins 1,5 l/min d'eau et la capacité d'offrir un positionnement sans fil sans avoir besoin d'accéder à un réseau cellulaire ou WiFi, pour une annotation précise des sources d'eau, la localisation des systèmes de désinfection égarés ou perdus et les capacités de positionnement autonomes des utilisateurs, sont des caractéristiques attrayantes pour améliorer la qualité de vie des personnes ayant un accès limité à l'eau potable ou à l'eau qui répond aux critères de qualité internationaux. This paper provides a unique multi-disciplinary survey of standalone solutions for clean and sustainable water access in Africa and proposes a three-segment architecture, comprised of an UV-LEDbased water disinfection unit, a solar-powered battery, and a wireless positioning system.In addition, our paper also provides initial snapshot results from all the three segments of the proposed architecture, as well as two examples of the water analysis and user-survey-based results collected from Togo, Africa.We believe that the features of our envisaged system such as long battery life, low maintenance cost, ability to significantly increase the quality and disinfect at least 1.5 l/min of water and ability to offer wireless positioning without the need to access a cellular or WiFi network, for accurate annotation of water sources, localization of misplaced or lost disinfection systems, and user standalone positioning capabilities, are attractive features towards improving the quality of life of people with limited access to potable water or to water that fulfills international quality criteria. تقدم هذه الورقة مسحًا فريدًا متعدد التخصصات للحلول المستقلة للوصول إلى المياه النظيفة والمستدامة في أفريقيا وتقترح بنية من ثلاثة أجزاء، تتألف من وحدة تطهير المياه القائمة على الأشعة فوق البنفسجية، وبطارية تعمل بالطاقة الشمسية، ونظام تحديد المواقع اللاسلكي. بالإضافة إلى ذلك، توفر ورقتنا أيضًا نتائج اللقطات الأولية من جميع الأجزاء الثلاثة للهندسة المعمارية المقترحة، بالإضافة إلى مثالين على تحليل المياه والنتائج المستندة إلى مسح المستخدم التي تم جمعها من توغو، أفريقيا. نعتقد أن ميزات نظامنا المتصور مثل عمر البطارية الطويل، وتكلفة الصيانة المنخفضة، والقدرة على زيادة جودة وتطهير ما لا يقل عن 1.5 لتر/دقيقة من المياه والقدرة على توفير تحديد المواقع اللاسلكية دون الحاجة إلى الوصول إلى شبكة خلوية أو شبكة واي فاي، للحصول على شرح دقيق لمصادر المياه، وتوطين أنظمة التطهير في غير محلها أو المفقودة، وقدرات تحديد المواقع القائمة بذاتها للمستخدم، هي ميزات جذابة نحو تحسين نوعية حياة الأشخاص الذين يعانون من محدودية الوصول إلى المياه الصالحة للشرب أو المياه التي تفي بالمعايير الدولية للجودة.