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- ItemAn Overview on the Role of Relative Humidity in Airborne Transmission of SARS-CoV-2 in Indoor Environments(Taoyuan City : Taiwan Association for Aerosol Research (TAAR), 2020) Ahlawat, Ajit; Wiedensohler, Alfred; Mishra, Sumit KumarCOVID-19 disease is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which originated in Wuhan, China and spread with an astonishing rate across the world. The transmission routes of SARS-CoV-2 are still debated, but recent evidence strongly suggests that COVID-19 could be transmitted via air in poorly ventilated places. Some studies also suggest the higher surface stability of SARS-CoV-2 as compared to SARS-CoV-1. It is also possible that small viral particles may enter into indoor environments from the various emission sources aided by environmental factors such as relative humidity, wind speed, temperature, thus representing a type of an aerosol transmission. Here, we explore the role of relative humidity in airborne transmission of SARS-CoV-2 virus in indoor environments based on recent studies around the world. Humidity affects both the evaporation kinematics and particle growth. In dry indoor places i.e., less humidity (< 40% RH), the chances of airborne transmission of SARS-CoV-2 are higher than that of humid places (i.e., > 90% RH). Based on earlier studies, a relative humidity of 40–60% was found to be optimal for human health in indoor places. Thus, it is extremely important to set a minimum relative humidity standard for indoor environments such as hospitals, offices and public transports for minimization of airborne spread of SARS-CoV-2. © The Author(s).
- ItemTwo-Phase Fluid Flow Experiments Monitored by NMR(Les Ulis : EDP Sciences, 2020) Hiller, Thomas; Hoder, Gabriel; Amann-Hildenbrand, Alexandra; Klitzsch, Norbert; Schleifer, NorbertWe present a newly developed high-pressure nuclear magnetic resonance (NMR) flow cell, which allows for the simultaneous determination of water saturation, effective gas permeability and NMR relaxation time distribution in two-phase fluid flow experiments. We introduce both the experimental setup and the experimental procedure on a tight Rotliegend sandstone sample. The initially fully water saturated sample is systematically drained by a stepwise increase of gas (Nitrogen) inlet pressure and the drainage process is continuously monitored by low field NMR relaxation measurements. After correction of the data for temperature fluctuations, the monitored changes in water saturation proved very accurate. The experimental procedure provides quantitative information about the total water saturation as well as about its distribution within the pore space at defined differential pressure conditions. Furthermore, the relationship between water saturation and relative (or effective) apparent permeability is directly determined. © The Authors, published by EDP Sciences, 2020.
- ItemA new method for correcting temperature log profiles in low-enthalpy plays(Berlin ; Heidelberg [u.a.] : Springer Open, 2020) Schumacher, Sandra; Moeck, IngaTemperature logs recorded shortly after drilling operations can be the only temperature information from deep wells. However, these measurements are still influenced by the thermal disturbance caused by drilling and therefore do not represent true rock temperatures. The magnitude of the thermal disturbance is dependent on many factors such as drilling time, logging procedure or mud temperature. However, often old well reports lack this crucial information so that conventional corrections on temperature logs cannot be performed. This impedes the re-evaluation of well data for new exploration purposes, e.g. for geothermal resources. This study presents a new method to correct log temperatures in low-enthalpy play types which only requires a knowledge of the final depth of the well as an input parameter. The method was developed and verified using existing well data from an intracratonic sedimentary basin, the eastern part of the North German Basin. It can be transferred to other basins with little or no adjustment. © 2020, The Author(s).
- ItemPredictability and controlling factors of overpressure in the North Alpine Foreland Basin, SE Germany: an interdisciplinary post-drill analysis of the Geretsried GEN-1 deep geothermal well(Berlin ; Heidelberg [u.a.] : Springer Open, 2020) Drews, Michael C.; Hofstetter, Peter; Zosseder, Kai; Shipilin, Vladimir; Stollhofen, HaraldThe North Alpine Foreland Basin in SE Germany is Germany’s most active deep geothermal province. However, in its southern and eastern part the basin is considerably overpressured, which is a significant challenge for drilling deep geothermal wells. In this study, we combine drilling data and velocity-based pore pressure analyses with 3D basin modeling to assess the predictability and controlling factors of overpressure in the sub-regional context (area of 80 km × 50 km) around the Geretsried GEN-1 well, a deep geothermal exploration well in the southern part of the North Alpine Foreland Basin in SE Germany. Drilling data and velocity-based pore pressure analyses indicate overpressure maxima in the Lower Oligocene (Rupelian and Schoeneck Formation) and up to mild overpressure in the Upper Oligocene (Chattian) and Upper Cretaceous, except for the hydrostatically pressured northwestern part of the study area. 3D basin modeling calibrated to four hydrocarbon wells surrounding the Geretsried GEN-1 well demonstrates the dominating role of disequilibrium compaction and low permeability units related to overpressure generation in the North Alpine Foreland Basin. However, secondary overpressure generation mechanisms are likely contributing. Also, the impact of Upper Cretaceous shales, which are eroded in the northwestern part of the study area, on overpressure maintenance is investigated. The calibrated basin model is tested against the drilling history and velocity (VSP) data-based pore pressure estimate of the Geretsried GEN-1 well and reveals that pore pressure prediction is generally possible using 3D basin modeling in the North Alpine Foreland Basin, but should be improved with more detailed analysis of lateral drainage systems and facies variations in the future. The results of the study are of relevance to future well planning and drilling as well as to geomechanical modeling of subsurface stresses and deep geothermal production in the North Alpine Foreland Basin. © 2020, The Author(s).
- ItemIon dynamics in Al-Stabilized Li7La3Zr2O12 single crystals – Macroscopic transport and the elementary steps of ion hopping(Amsterdam : Elsevier, 2020) Posch, Patrick; Lunghammer, Sarah; Berendts, Stefan; Ganschow, Steffen; Redhammer, Günther J.; Wilkening, Alexandra; Lerch, Martin; Gadermaier, Bernhard; Rettenwander, Daniel; Wilkening, H. Martin R.Li7La3Zr2O12 (LLZO) garnet-type ceramics are considered as very promising candidates for solid electrolytes and have been extensively studied in the past few years. Several studies report on an increase in ionic conductivity by doping with ions, such as Al3+ and Ga3+, to stabilize the cubic modification of LLZO. Unfortunately, so far ion dynamics have mainly been studied using powdered samples. Such studies may suffer from chemical heterogeneities concerning Al distribution. Here, we took advantage of Al-stabilized LLZO single crystals to throw light on the elementary steps of ion hopping. We used 7Li nuclear magnetic resonance (NMR) spin-lattice relaxation measurements and conductivity spectroscopy to probe dynamic parameters from both a microscopic and macroscopic point of view. At 293 K the total conductivity turned out to be 0.082 mS cm−1, which is remarkably good for LLZO exhibiting an Al-content of only 0.37 wt%. Most importantly, 7Li NMR spin-lock transients revealed two overlapping diffusion-induced processes. Overall, activation energies from spin-lock NMR excellently agree with that from conductivity measurements; both techniques yield values around 0.36 eV. The corresponding diffusion coefficients deduced from NMR and conductivity measurements almost coincide. The magnetic spin fluctuations sensed by NMR provide an in-depth look at the elementary jump processes, which can barely be revealed by macroscopic impedance spectroscopy providing average values. In particular, we were able to precisely measure the local hopping barrier (0.20 eV) characterizing forward-backward jumps between the sites 24d and 96h. © 2019 The Author(s)
- ItemNo Evidence for a Significant Impact of Heterogeneous Chemistry on Radical Concentrations in the North China Plain in Summer 2014(Columbus, Ohio : American Chemical Society, 2020) Tan, Zhaofeng; Hofzumahaus, Andreas; Lu, Keding; Brown, Steven S.; Holland, Frank; Huey, Lewis Gregory; Kiendler-Scharr, Astrid; Li, Xin; Liu, Xiaoxi; Ma, Nan; Min, Kyung-Eun; Rohrer, Franz; Shao, Min; Wahner, Andreas; Wang, Yuhang; Wiedensohler, Alfred; Wu, Yusheng; Wu, Zhijun; Zeng, Limin; Zhang, Yuanhang; Fuchs, HendrikThe oxidation of nitric oxide to nitrogen dioxide by hydroperoxy (HO2) and organic peroxy radicals (RO2) is responsible for the chemical net ozone production in the troposphere and for the regeneration of hydroxyl radicals, the most important oxidant in the atmosphere. In Summer 2014, a field campaign was conducted in the North China Plain, where increasingly severe ozone pollution has been experienced in the last years. Chemical conditions in the campaign were representative for this area. Radical and trace gas concentrations were measured, allowing for calculating the turnover rates of gas-phase radical reactions. Therefore, the importance of heterogeneous HO2 uptake on aerosol could be experimentally determined. HO2 uptake could have suppressed ozone formation at that time because of the competition with gas-phase reactions that produce ozone. The successful reduction of the aerosol load in the North China Plain in the last years could have led to a significant decrease of HO2 loss on particles, so that ozone-forming reactions could have gained importance in the last years. However, the analysis of the measured radical budget in this campaign shows that HO2 aerosol uptake did not impact radical chemistry for chemical conditions in 2014. Therefore, reduced HO2 uptake on aerosol since then is likely not the reason for the increasing number of ozone pollution events in the North China Plain, contradicting conclusions made from model calculations reported in the literature. © 2020 American Chemical Society.
- ItemDo Benefits from Dynamic Tariffing Rise? Welfare Effects of Real-Time Retail Pricing Under Carbon Taxation and Variable Renewable Electricity Supply(Dordrecht [u.a.] : Springer Science + Business Media B.V., 2020) Gambardella, Christian; Pahle, Michael; Schill, Wolf-PeterWe analyze the gross welfare gains from real-time retail pricing in electricity markets where carbon taxation induces investment in variable renewable technologies. Applying a stylized numerical electricity market model, we find a U-shaped association between carbon taxation and gross welfare gains. The benefits of introducing real-time pricing can accordingly be relatively low at relatively high carbon taxes and vice versa. The non-monotonous change in welfare gains can be explained by corresponding changes in the inefficiency arising from “under-consumption” during low-price periods rather than by changes in wholesale price volatility. Our results may cast doubt on the efficiency of ongoing roll-outs of advanced meters in many electricity markets, since net benefits might only materialize at relatively high carbon tax levels and renewable supply shares. © 2019, The Author(s).
- ItemMulti-method evidence for when and how climate-related disasters contribute to armed conflict risk(Amsterdam [u.a.] : Elsevier, 2020) Ide, Tobias; Brzoska, Michael; Donges, Jonathan F.; Schleussner, Carl-FriedrichClimate-related disasters are among the most societally disruptive impacts of anthropogenic climate change. Their potential impact on the risk of armed conflict is heavily debated in the context of the security implications of climate change. Yet, evidence for such climate-conflict-disaster links remains limited and contested. One reason for this is that existing studies do not triangulate insights from different methods and pay little attention to relevant context factors and especially causal pathways. By combining statistical approaches with systematic evidence from QCA and qualitative case studies in an innovative multi-method research design, we show that climate-related disasters increase the risk of armed conflict onset. This link is highly context-dependent and we find that countries with large populations, political exclusion of ethnic groups, and a low level of human development are particularly vulnerable. For such countries, almost one third of all conflict onsets over the 1980-2016 period have been preceded by a disaster within 7 days. The robustness of the effect is reduced for longer time spans. Case study evidence points to improved opportunity structures for armed groups rather than aggravated grievances as the main mechanism connecting disasters and conflict onset. © 2020 The Authors
- ItemAssessment of the growth in social groups for sustainable agriculture and land management(Cambridge : Cambridge Univ. Press, 2020) Pretty, Jules; Attwood, Simon; Bawden, Richard; van den Berg, Henk; Bharucha, Zareen P.; Dixon, John; Butler Flora, Cornelia; Gallagher, Kevin; Genskow, Ken; Hartley, Sue E.; Ketelaar, Jan Willem; Kiara, Japhet K.; Kumar, Vijay; Lu, Yuelai; MacMillan, Tom; Maréchal, Anne; Morales-Abubakar, Alma Linda; Noble, Andrew; Prasad, P. V. Vara; Rametsteiner, Ewald; Reganold, John; Ricks, Jacob I.; Rockström, Johan; Saito, Osamu; Thorne, Peter; Wang, Songliang; Wittman, Hannah; Winter, Michael; Yang, PuyunNon-technical summary Until the past half-century, all agriculture and land management was framed by local institutions strong in social capital. But neoliberal forms of development came to undermine existing structures, thus reducing sustainability and equity. The past 20 years, though, have seen the deliberate establishment of more than 8 million new social groups across the world. This restructuring and growth of rural social capital within specific territories is leading to increased productivity of agricultural and land management systems, with particular benefits for those previously excluded. Further growth would occur with more national and regional policy support. Technical summary For agriculture and land management to improve natural capital over whole landscapes, social cooperation has long been required. The political economy of the later twentieth and early twenty-first centuries prioritized unfettered individual action over the collective, and many rural institutions were harmed or destroyed. Since then, a wide range of social movements, networks and federations have emerged to support transitions towards sustainability and equity. Here, we focus on social capital manifested as intentionally formed collaborative groups within specific geographic territories. These groups focus on: (1) integrated pest management; (2) forests; (3) land; (4) water; (5) pastures; (6) support services; (7) innovation platforms; and (8) small-scale systems. We show across 122 initiatives in 55 countries that the number of groups has grown from 0.50 million (in 2000) to 8.54 million (in 2020). The area of land transformed by the 170–255 million group members is 300 Mha, mostly in less-developed countries (98% groups; 94% area). Farmers and land managers working with scientists and extensionists in these groups have improved both environmental outcomes and agricultural productivity. In some cases, changes to national or regional policy supported this growth in groups. Together with other movements, these social groups could now support further transitions towards policies and behaviours for global sustainability. Social media summary Millions of geographically based new social groups are leading to more sustainable agriculture and forestry worldwide. © The Author(s), 2020.
- ItemShared Socio-economic Pathways for European agriculture and food systems: The Eur-Agri-SSPs(Amsterdam [u.a.] : Elsevier, 2020) Le Mouël, Chantal; Mathijs, Erik; Mehdi, Bano; Mittenzwei, Klaus; Mora, Olivier; Øistad, Knut; Øygarden, Lillian; Priess, Jörg A.; Reidsma, Pytrik; Schaldach, Rüdiger; Schönhart, Martin; Mitter, Hermine; Techen, Anja-K.; Sinabell, Franz; Helming, Katharina; Schmid, Erwin; Bodirsky, Benjamin L.; Holman, Ian; Kok, Kasper; Lehtonen, Heikki; Leip, AdrianScenarios describe plausible and internally consistent views of the future. They can be used by scientists, policymakers and entrepreneurs to explore the challenges of global environmental change given an appropriate level of spatial and sectoral detail and systematic development. We followed a nine-step protocol to extend and enrich a set of global scenarios – the Shared Socio-economic Pathways (SSPs) – providing regional and sectoral detail for European agriculture and food systems using a one-to-one nesting participatory approach. The resulting five Eur-Agri-SSPs are titled (1) Agriculture on sustainable paths, (2) Agriculture on established paths, (3) Agriculture on separated paths, (4) Agriculture on unequal paths, and (5) Agriculture on high-tech paths. They describe alternative plausible qualitative evolutions of multiple drivers of particular importance and high uncertainty for European agriculture and food systems. The added value of the protocol-based storyline development process lies in the conceptual and methodological transparency and rigor; the stakeholder driven selection of the storyline elements; and consistency checks within and between the storylines. Compared to the global SSPs, the five Eur-Agri-SSPs provide rich thematic and regional details and are thus a solid basis for integrated assessments of agriculture and food systems and their response to future socio-economic and environmental changes. © 2020 The Author(s)
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