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Changing our unsustainable linear water management pattern is necessary to face growing global water challenges. This article proposes an integrated framework to analyse and understand the role of different contextual conditions in the possible transition towards water circularity. Our framework combines a systematic multi-level perspective to explore the water system and the institutional work theory for technology legitimation. The framework consists of the following stages: (1) describing and understanding the water context, (2) assessment of the selected technologies’ circularity level, (3) assessment of the alternative circular technologies’ legitimacy, and (4) identification of the legitimation actions to support the upscale of alternative circular technologies. The practical applicability of the integrated assessment framework and its four assessment stages was demonstrated in the exploration of circular water technologies for the horticulture sector in Westland, the Netherlands. The results revealed the conditions that hinder or enable the legitimation of the circular water technologies, such as political environmentalism, trust in water governing authorities, and technical, financial, and knowledge capabilities.
This market research paper has been prepared under the supervision of Prof. Dr. Agnieszka Gehringer of TH Köln and Prof. Dr. Carol Scovotti of University of Wisconsin-Whitewater in the course of the inter-university cross-border collaboration student research project “Export Opportunity Surveys (EOS)”. This study explores organic oranges export opportunities to the German and US markets.
Decisions on irrigation water management are usually made at different levels, including farms, water user associations (WUAs), and regional water planning agencies. The latter generally have good access to information and decision tools regarding water resources management. However, these remain out of reach to the final water users, namely the farmers. The study, conducted in the irrigated district of Cherfech, north Tunisia, had the main objective of investigating farmer’s perceptions of, and acceptance for, the use of an irrigation advisory service (IAS) to be implemented by their WUA. The suggested IAS provides the following information: (1) reference evapotranspiration (ETo) and rainfall; (2) crop water requirement (CWR) of the most cultivated crops; (3) irrigation water requirement (IWR) of the farmer’s crop; and (4) crop monitoring and real-time estimation of IWR of crops settled, using soil moisture sensors. Such services and information would be available at the WUA level and provided in a timely manner to farmers for more effective decision making at the plot level. Prior to the acceptance study, we launched a technical study to determine the required tools and equipment required for the implementation of the IAS, followed by a farmer survey to assess their respective perceptions and acceptance towards this IAS. Results showed that only 54% of the farmers are satisfied by WUAs work, but that 77% of them accepted using the suggested IAS. Farmers are also willing to pay for most of the IAS packages suggested. The financial profitability of investing in the IAS at the WUA level shows the venture is financially viable, with a benefit cost ratio (BCR) of 1.018. The project will be even more profitable if we add the social benefits, which may result in water savings at the WUA level.
The management of the liquid fraction of digestate produced from the anaerobic digestion of biodegradable municipal solid waste is a difficult affair, as its land application is limited due to high ammonium concentrations and the municipal waste that water treatment plants struggle to treat due to high pollutant loads. The amount of leachate and the pollutant load in the leachate produced by landfills usually decreases with the time, which increases the capacity of landfill leachate treatment plants (LLTPs) to treat additional wastewater. In order to solve the above two challenges, the co-treatment of landfill leachate and the liquid fraction of anaerobic digestate in an industrial-scale LLTP was investigated along with the long-term impacts of the liquid fraction of anaerobic digestate on biocoenosis and its impact on LLTP operational expenses. The co-treatment of landfill leachate and liquid fraction of anaerobic digestate was compared to conventional leachate treatment in an industrial-scale LLTP, which included the use of two parallel lanes (Lane-1 and Lane-2). The average nitrogen removal efficiencies in Lane-1 (co-treatment) were 93.4%, 95%, and 92%, respectively, for C/N ratios of 8.7, 8.9, and 9.4. The average nitrogen removal efficiency in Lane-2 (conventional landfill leachate treatment), meanwhile, was 88%, with a C/N ratio of 6.5. The LLTP’s average chemical oxygen demand (COD) removal efficiencies were 63.5%, 81%, and 78% during phases one, two, and three, respectively. As the volume ratios of the liquid fraction of anaerobic digestate increased, selective oxygen uptake rate experiments demonstrated the dominance of heterotrophic bacteria over ammonium and nitrite-oxidising organisms. The inclusion of the liquid fraction of anaerobic digestate during co-treatment did not cause a significant increase in operational resources, i.e., oxygen, the external carbon source, activated carbon, and energy.
Conventional individual head-related transfer function (HRTF) measurements are demanding in terms of measurement time and equipment. For more flexibility, free body movement (FBM) measurement systems provide an easy-to-use way to measure full-spherical HRTF datasets with less effort. However, having no fixed measurement installation implies that the HRTFs are not sampled on a predefined regular grid but rely on the individual movements of the subject. Furthermore, depending on the measurement effort, a rather small number of measurements can be expected, ranging, for example, from 50 to 150 sampling points. Spherical harmonics (SH) interpolation has been extensively studied recently as one method to obtain full-spherical datasets from such sparse measurements, but previous studies primarily focused on regular full-spherical sampling grids. For irregular grids, it remains unclear up to which spatial order meaningful SH coefficients can be calculated and how the resulting interpolation error compares to regular grids. This study investigates SH interpolation of selected irregular grids obtained from HRTF measurements with an FBM system. Intending to derive general constraints for SH interpolation of irregular grids, the study analyzes how the variation of the SH order affects the interpolation results. Moreover, the study demonstrates the importance of Tikhonov regularization for SH interpolation, which is popular for solving ill-posed numerical problems associated with such irregular grids. As a key result, the study shows that the optimal SH order that minimizes the interpolation error depends mainly on the grid and the regularization strength but is almost independent of the selected HRTF set. Based on these results, the study proposes to determine the optimal SH order by minimizing the interpolation error of a reference HRTF set sampled on the sparse and irregular FBM grid. Finally, the study verifies the proposed method for estimating the optimal SH order by comparing interpolation results of irregular and equivalent regular grids, showing that the differences are small when the SH interpolation is optimally parameterized.
Pressure injuries remain a serious health complication for patients and nursing staff. Evidence from the past decade has not been analysed through narrative synthesis yet. PubMed, Embase, CINAHL Complete, Web of Science, Cochrane Library, and other reviews/sources were screened. Risk of bias was evaluated using a slightly modified QUIPS tool. Risk factor domains were used to assign (non)statistically independent risk factors. Hence, 67 studies with 679,660 patients were included. In low to moderate risk of bias studies, non-blanchable erythema reliably predicted pressure injury stage 2. Factors influencing mechanical boundary conditions, e.g., higher interface pressure or BMI < 18.5, as well as factors affecting interindividual susceptibility (male sex, older age, anemia, hypoalbuminemia, diabetes, hypotension, low physical activity, existing pressure injuries) and treatment-related aspects, such as length of stay in intensive care units, were identified as possible risk factors for pressure injury development. Health care professionals’ evidence-based knowledge of above-mentioned risk factors is vital to ensure optimal prevention and/or treatment. Openly accessible risk factors, e.g., sex, age, BMI, pre-existing diabetes, and non-blanchable erythema, can serve as yellow flags for pressure injury development. Close communication concerning further risk factors, e.g., anemia, hypoalbuminemia, or low physical activity, may optimize prevention and/or treatment. Further high-quality evidence is warranted.
Die Bedeutung von Cyber-Versicherungen als Instrument zur finanziellen Absicherung, um die zunehmenden Unternehmensverluste durch Cyber-Risiken abzumildern, nimmt zu. Es mangelt jedoch an standardisierten Wordings und gegenseitigem Verständnis bei Cyberversicherungs-Policen. Mit weniger als einem Drittel der 2017 in den USA ausgezahlten Cyberversicherungsansprüche besteht eine erhebliche Lücke zwischen den Cyber-Risiken, die Unternehmen abdecken müssen, und denen, die tatsächlich durch ihre Cyberversicherungspolicen abgedeckt sind. Im Jahre 2018 wurde von Lloyds of London eine Schätzung mithilfe von Szenario-basierten Modellen durchgeführt, um zu ermitteln, wie groß die Versicherungsschutzlücke im Hinblick auf Cyber-Risiken ist. Man ist dabei zu dem Ergebnis gekommen, dass die Versicherungsschutzlücke ungefähr 90 % beträgt. Der Begriff bezeichnet die Differenz zwischen dem Versicherungsschutz, welcher ökonomisch benötigt wird und dem tatsächlich gekauften.
Diese Forschung befasste sich mit den deutschen Cyber-Versicherern, welche Cyber-Schutz für kleine und mittelständische Unternehmen (KMU) anbieten. Im Rahmen dieser Forschung wurden nur die Ausschlüsse von Cyber-Versicherungen betrachtet. Zusätzliche erweiterbare oder kostenpflichtige Einschlüsse wurden nicht berücksichtigt. Als Grundlage für die Forschung wurde ein Datensatz erstellt, welcher auf Informationen der BaFin basiert. Durch mehrere Segmentierungsstufen wurden 50 Cyber-Versicherer ermittelt, welche Cyber-Schutz für KMUs angeboten haben. Von diesen 50 Cyber-Versicherern konnten 41 Cyber-Bedingungswerke für das Forschungsprojekt herangezogen werden. Im Rahmen der Forschung wurden nun die Bedingungswerke mittels einer induktiven qualitativen Inhaltsanalyse auf die bestehenden Ausschlüsse analysiert. Die Ergebnisse wurden kategorisiert und beschrieben. Innerhalb der Analyse konnten 15 Ausschlusskategorien sowie deren Häufigkeiten in den Cyber-Bedingungen ermittelt werden. Diese Ergebnisse können dazu beitragen, dass Unternehmen eine Vorstellung davon erhalten, was nicht in den Cyber-Versicherungen enthalten sein könnte. Zudem liefern die Beschreibungen eine Informationsgrundlage und tragen so dazu bei, dass der Versicherungsschutz bzw. die Ausschlüsse besser verstanden werden.
Die Kriterien zur Nachhaltigkeit werden unter der Abkürzung ESG zusammengefasst und sind somit nicht nur auf den reinen Klimawandel begrenzt. Grundsätzlich versteht man unter sogenannten ESG-Kriterien per Definition einen Standard nachhaltiger Investments in den Bereichen Environment/ Umwelt, Social/ gesellschaftliches Engagement und Governance/ Unternehmensführung. (vgl. Haberstock et al., 2019)
Sowohl Erst- und Rückversicherungsunternehmen als auch Retrozessionspartner und Investoren beziehen bei ihrer Geschäftsentscheidung zunehmend Nachhaltigkeitsaspekte mit ein. Sie achten unter anderem auf die Nachhaltigkeit der Kapitalanlagen und die entsprechenden Entscheidungen im Underwriting oder bewerten das soziale Engagement eines Vertragspartners. Deshalb kann sich ein überzeugendes Nachhaltigkeitsprofil auch sukzessive zu einem Wettbewerbsvorteil entwickeln.
Das Kerngeschäft der Rückversicherungsbranche wird immer wieder von neuartigen Risiken und globalen Herausforderungen geprägt.
Eine ESG-konforme Geschäftsausrichtung und eine entsprechende Anpassung im Underwriting stellt den Rückversicherungs- und Retrozessionsmarkt vor neue Herausforderungen, da gewisse ESG-Kriterien eine Hürde für fortlaufende Geschäftstätigkeiten im Underwriting darstellen.
Die Umsetzung einer ESG-konformen Geschäftsausrichtung in der Retrozession geht einher mit der Rekalibrierung des Risikoappetits und mit der Aufnahme von einheitlichen zukünftigen ESG-Ratings, die sowohl zu Vorteilen als auch Nachteilen in der Wettbewerbsfähigkeit führen können.
Vergleicht man die ESG-Faktoren zwischen Retrozedenten und Retrozessionären lässt sich feststellen, dass die ESG-Faktoren für Retrozedenten bei der Kapazitätssuche wichtig sind. Hingegen die Faktoren beim Kapazitätsangebot für Retrozessionäre weniger wichtig sind. Diese Erkenntnis wird dadurch begründet, dass sich Retrozedenten bereits im vorgelagerten Underwriting der eingehenden Risiken mit den ESG-Kriterien beschäftigen müssen und dadurch bereits einen besseren Überblick über diese Faktoren haben. Zudem müssen sich die Retrozedenten im Detail mit den möglichen Retrozessionären und deren ESG-Strategie beschäftigen, damit die ESG-konforme Geschäftsausrichtung gewahrt wird.
Eine ESG-konforme Geschäftsausrichtung und die Berücksichtigung der ESG-Risiken führt zwangsläufig zu einer Anpassung der Geschäftsstrategie, der internen Aufsichtsstrukturen, des Risikomanagements und zu einer Änderung des Pricings von Retrozessionsrisiken.
The oxidation of cumene and following cleavage of cumene hydroperoxide (CHP) with sulfuric acid (Hock rearrangement) is still, by far, the dominant synthetic route to produce phenol. In 2020, the global phenol market reached a value of 23.3 billion US$ with a projected compound annual growth rate of 3.4% for 2020–2025. From ecological and economical viewpoints, the key step of this process is the cleavage of CHP. One sought-after way to likewise reduce energy consumption and waste production of the process is to substitute sulfuric acid with heterogeneous catalysts. Different types of zeolites, silicon-based clays, heteropoly acids, and ion exchange resins have been investigated and tested in various studies. For every type of these solid acid catalysts, several materials were found that show high yield and selectivity to phenol. In this mini-review, first a brief introduction and overview on the Hock process is given. Next, the mechanism, kinetics, and safety aspects are summarized and discussed. Following, the different types of heterogeneous catalysts and their performance as catalyst in the Hock process are illustrated. Finally, the different approaches to substitute sulfuric acid in the synthetic route to produce phenol are briefly concluded and a short outlook is given.
Abstract
(−)‐Menthol is one of the most popular aroma compounds worldwide. While in the past mostly extracted from mint plants, today (−)‐menthol synthesis from other raw materials is becoming more relevant. Common starting materials for menthol synthesis are m‐cresol, citral and myrcene, but also substrates like menthone, mono‐ and bicyclic terpenes and terpenoids have been used for this purpose in the past. As for many applications (−)‐menthol of high purity is required, asymmetric syntheses and enantiomeric resolution of obtained raw products are applied for menthol production. This review gives an overview on the most important synthetic menthol production processes of the companies Symrise, Takasago and BASF and relevant literature in the field of menthol synthesis with a focus on the last 20 years.
Electroplating generates high volumes of rinse water that is contaminated with heavy metals. This study presents an approach for direct metal recovery and recycling from simulated rinse water, made up of an electroplating electrolyte used in industry, using reverse osmosis (RO). To simulate the real industrial application, the process was examined at various permeate fluxes, ranging from 3.75 to 30 L·m−2·h−1 and hydraulic pressures up to 80 bar. Although permeance decreased significantly with increasing water recovery, rejections of up to 93.8% for boric acid, >99.9% for chromium and 99.6% for sulfate were observed. The final RO retentate contained 8.40 g/L chromium and was directly used in Hull cell electroplating tests. It was possible to deposit cold-hued chromium layers under a wide range of relevant current densities, demonstrating the reusability of the concentrate of the rinsing water obtained by RO.
New risk geographies are emerging with war and conflict resurfacing, including nuclear threats. This poses challenges to civil protection for conducting risk-informed preparedness planning. A spatial assessment of Germany and Europe is conducted using a geographic information system. Buffer circles of nuclear explosion effects and fallout buffers show potentially exposed areas around major cities. Different scenarios indicate shrinking areas safe from exposure. However, even in a densely populated country, rural areas and smaller cities can be identified that could provide sites for evacuation shelters. Changing wind directions poses a challenge for civil protection planning because fallout risk covers most German territory even when few cities are attacked. However, wind speeds and topography can help identify suitable shelter areas. More knowledge about the temporal development of a nuclear explosion and its specific forms of harm can also help to improve risk knowledge and planning. While nuclear warfare at first seems to render useless any option for safe areas and survival, the spatial risk assessment shows that exposure does not occur at all places at all times. Being safe from harm will be difficult in such a worst-case scenario, but avoiding large city perimeters and being informed can also help reduce risk.
This project was done in collaboration with CERN and is part of the detector control system of the ATLAS experiment. The primary goal foresaw the development and testing of the FPGA card for the MOPS-HUB crate with the focus on radiation tolerance. This was accomplished with the approach of designing two different PCBs. The first PCB was created as a fast prototype with the use of a commercial SOM-board. This was also beneficial for confirming that the chosen FPGA is suitable for the MOPS-HUB application. After the successful assembly and test, a second, more complex and foremost radiation tolerant PCB was designed. This was achieved by solely using components of the CERN radiation database.
The second part of this thesis focuses on increasing the distance of TMR registers with a Python script. A method was created for extracting and later parsing a design’s placement
information from Vivado. Furthermore, were system designed and implemented to recognize TMR cells, to find and validate free cells and to finally create a new placement for import into Vivado. These algorithms were tested with a multitude of configurations and the quality, based on the maximum possible frequency of a design, determined.
AbstractThe Ganges-Brahmaputra (GB) delta is one of the most disaster-prone areas in the world due to a combination of high population density and exposure to tropical cyclones, floods, salinity intrusion and other hazards. Due to the complexity of natural deltaic processes and human influence on these processes, structural solutions like embankments are inadequate on their own for effective hazard mitigation. This article examines nature-based solutions (NbSs) as a complementary or alternative approach to managing hazards in the GB delta. We investigate the potential of NbS as a complementary and sustainable method for mitigating the impacts of coastal disaster risks, mainly cyclones and flooding. Using the emerging framework of NbS principles, we evaluate three existing approaches: tidal river management, mangrove afforestation, and oyster reef cultivation, all of which are actively being used to help reduce the impacts of coastal hazards. We also identify major challenges (socioeconomic, biophysical, governance and policy) that need to be overcome to allow broader application of the existing approaches by incorporating the NbS principles. In addition to addressing GB delta-specific challenges, our findings provide more widely applicable insights into the challenges of implementing NbS in deltaic environments globally.
Climate change includes the change of the long-term average values and the change of the tails of probability density functions, where the extreme events are located. However, obtaining average values are more straightforward than the high temporal resolution information necessary to catch the extreme events on those tails. Such information is difficult to get in areas lacking sufficient rain stations. Thanks to the development of Satellite Precipitation Estimates with a daily resolution, this problem has been overcome, so Extreme Precipitation Indices (EPI) can be calculated for the entire Colombian territory. However, Colombia is strongly affected by the ENSO (El Niño—Southern Oscillation) phenomenon. Therefore, it is pertinent to ask if the EPI’s long-term change due to climate change is more critical than the anomalies due to climate variability induced by the warm and cold phases of ENSO (El Niño and La Niña, respectively). In this work, we built EPI annual time series at each grid-point of the selected Satellite Precipitation Estimate (CHIRPSv2) over Colombia to answer the previous question. Then, the Mann-Whitney-Wilcoxon test was used to compare the samples drawn in each case (i.e., change tests due to both long-term and climatic variability). After performing the analyses, we realized that the importance of the change depends on the region analyzed and the considered EPI. However, some general conclusions became evident: during El Niño years (La Niña), EPI’s anomaly follows the general trend of reduction -drier conditions- (increase; -wetter conditions-) observed in Colombian annual precipitation amount, but only on the Pacific, the Caribbean, and the Andean region. In the Eastern plains of Colombia (Orinoquía and Amazonian region), EPI show a certain insensitivity to change due to climatic variability. On the other hand, EPI’s long-term changes in the Pacific, the Caribbean, and the Andean region are spatially scattered. Still, long-term changes in the eastern plains have a moderate spatial consistency with statistical significance.
In this study the link between renewable energies and employment in Senegal is analyzed.
The Sustainable Livelihood Approach is used to understand the investigated situation in a holistic view. To successfully implement renewable energies in Senegal and to have a significant impact on the employment market, the governmental framework and the technical education has to improve, to match the needs of the labor market.
Rural communities do not have all the assets to lift themselves out of poverty and disadvantages by the usage of renewable energy. Solar irrigation, off-grid systems and solar devices impact the level of education and the labor force in rural areas in Senegal.
Moreover, access to a reliable energy source improves people’s livelihood in terms
of health, education, income and employment.
The resulting employment effect of adding 20 MW with the solar power plant Senergy 2 can be estimated with 28.686 created jobs (0,54 % of total employment).
Upcoming power projects offer employment opportunities for graduates of the master study renewable energies. Furthermore, the demand of specialized engineers and
technicians in the distribution and project planning sector will rise.
A bifacial Photovoltaic (PV) simulation model is created by combining the optical View Factor matrix with electrical output simulation in python to analyse the energy density of bifacial systems. A discretization of the rear side of the bifacial modules allows a further investigation of mismatching and losses due to inhomogeneous radiation distribution. The model is validated, showing a deviation of -1.25 % to previous simulation models and giving hourly resolvedoutput data with a higher accuracy than existing software for bifacial PV systems.
Speedrunning in general means to go fast in a video game. This simple concept has an immense impact on the ways players engage with games. The inherent aspect of optimization within this esports niche makes it a good application field of optimization methods. This work gives an overview of speedrunning as an esports discipline. Prior works on this subject are discussed and assessed and relevant nomenclature is introduced. Using this information, routing --- the procedure of planning a speedrun --- is picked up as a graph optimization problem.
Nintendo's iconic game The Legend of Zelda: Ocarina of Time from 1998 is used as a working example to assess previous works and to explore more of this mainly uncharted field of research.To do so, the process of speedrun modeling is conducted as exhaustive as possible within the limits of a work like this. All relevant steps to obtain a faithful model are lined out. This procedure yields a partial game graph with 6764 nodes and approx. 321,022 edges --- some uncertainty included. Current pathfinding techniques are discussed and assessed regarding their applicability to the presented speedrun routing problem. The resulting graph model and algorithmic approaches present a good reference to identify the most promising points of improvement. Challenges, flaws and possible solutions to still standing problems are discussed and assumptions from prior works are assessed. Finally, further tracks of scholarly and community work in this area are suggested and possible extensions to the approach are lined out.
It is shown that speedrun routing is not a trivial shortest path problem that can be solved with conventional methods. Furthermore, it is made clear that different games can have vastly differing routing circumstances. Assumptions of other works have been assessed using a working example and many interesting challenges and fields of further study and research in the field of speedrunning have been identified. Some probabilistic pathfinding methods and current works on AI agents for games pose interesting approaches which can be extended on by utilizing the findings of the presented work. Specialized modeling and optimization techniques have to be employed in order to have a positive effect on the speedrunning community.
In this work, supported cellulose acetate (CA) mixed matrix membranes (MMMs) were prepared and studied concerning their gas separation behaviors. The dispersion of carbon nanotube fillers were studied as a factor of polymer and filler concentrations using the mixing methods of the rotor–stator system (RS) and the three-roll-mill system (TRM). Compared to the dispersion quality achieved by RS, samples prepared using the TRM seem to have slightly bigger, but fewer and more homogenously distributed, agglomerates. The green γ-butyrolactone (GBL) was chosen as a polyimide (PI) polymer-solvent, whereas diacetone alcohol (DAA) was used for preparing the CA solutions. The coating of the thin CA separation layer was applied using a spin coater. For coating on the PP carriers, a short parameter study was conducted regarding the plasma treatment to affect the wettability, the coating speed, and the volume of dispersion that was applied to the carrier. As predicted by the parameter study, the amount of dispersion that remained on the carriers decreased with an increasing rotational speed during the spin coating process. The dry separation layer thickness was varied between about 1.4 and 4.7 μm. Electrically conductive additives in a non-conductive matrix showed a steeply increasing electrical conductivity after passing the so-called percolation threshold. This was used to evaluate the agglomeration behavior in suspension and in the applied layer. Gas permeation tests were performed using a constant volume apparatus at feed pressures of 5, 10, and 15 bar. The highest calculated CO2/N2 selectivity (ideal), 21, was achieved for the CA membrane and corresponded to a CO2 permeability of 49.6 Barrer.
Abstract
Two types (with and without a hydrolysis stabilizer) of polyamide 6.6 (PA6.6) reinforced with 30% w/w glass fibres were examined against the influence of automotive cooling fluids, e.g. ethylene glycol aqueous solutions. The overall goal was to find a methodology to compare the performance of PA6.6 materials against the impacts of the hydrolysis environment. The stabilizer effect on the hydrolytic resistance of the materials was assessed using tensile tests according to ISO 527, and their strain‐at‐break values were evaluated in more detail. The degradation mechanism of both PA types was monitored by infrared spectroscopy and SEM. The material lifetime was described by the Arrhenius equation. The results show that the hydrolysis stabilizer operates effectively at low temperature but exhibits weak performance above 130 °C, which is explained by faster consumption of the stabilizing agent. © 2021 The Authors. Polymer International published by John Wiley & Sons Ltd on behalf of Society of Industrial Chemistry.