Power-to-Syngas: A Parareal Optimal Control Approach

A chemical plant layout for the production of syngas from renewable power, H2O and biogas, is presented to ensure a steady productivity of syngas with a constant H2-to-CO ratio under time-dependent electricity provision. An electrolyzer supplies H2 to the reverse water-gas shift reactor. The system compensates for a drop in electricity supply by gradually operating a tri-reforming reactor, fed with pure O2 directly from the electrolyzer or from an intermediate generic buffering device. After the introduction of modeling assumptions and governing equations, suitable reactor parameters are identified. Finally, two optimal control problems are investigated, where computationally expensive model evaluations are lifted viaparareal and necessary objective derivatives are calculated via the continuous adjoint method. For the first time, modeling, simulation, and optimal control are applied to a combination of the reverse water-gas shift and tri-reforming reactor, exploring a promising pathway in the conversion of renewable power into chemicals

Dynamic flux balance modeling to increase the production of high-value compounds in green microalgae

Background Photosynthetic organisms can be used for renewable and sustainable production of fuels and high-value compounds from natural resources. Costs for design and operation of large-scale algae cultivation systems can be reduced if data from laboratory scale cultivations are combined with detailed mathematical models to evaluate and optimize the process. Results In this work we present a flexible modeling formulation for accumulation of high-value storage molecules in microalgae that provides quantitative predictions under various light and nutrient conditions. The modeling approach is based on dynamic flux balance analysis (DFBA) and includes regulatory models to predict the accumulation of pigment molecules. The accuracy of the model predictions is validated through independent experimental data followed by a subsequent model-based fed-batch optimization. In our experimentally validated fed-batch optimization study we increase biomass and β-carotene density by factors of about 2.5 and 2.1, respectively. Conclusions The analysis shows that a model-based approach can be used to develop and significantly improve biotechnological processes for biofuels and pigments

Kreislaufwirtschaft und Elektro-Bioökonomie: Neue Ansätze in der Nachhaltigkeitsforschung

In einem Gastbeitrag im Online-Seminar Bioökonomie im Juni 2020 an der Otto-von-Guericke Universität Magdeburg referierte Professor Sundmacher über den Beitrag der Bioökonomie, der Bio-Elektro-Ökonomie und der Kreislaufwirtschaft als sich ergänzende Säulen für ein nachhaltigeres Wirtschaften bis hin zur Vision der zirkulären Elektro-Bioökonomie und zeigte deren jeweilige Potenziale und Grenzen auf. Er erläuterte in seinem Vortrag, warum sich aus seiner Sicht die Bioökonomie wesentlich besser zur Produktion von Nahrungsmitteln, pharmazeutischen Wirkstoffen und chemischen Rohstoffen eignet als zur Erzeugung von Strom und Treibstoffen. Demgegenüber begründete Professor Sundmacher die bessere Eignung der Elektro-Ökonomie für die Strom- und Wasserstofferzeugung durch Wind- und Solarenergie sowie der Weiterverarbeitung von Wasserstoff zu E-Fuels mit Kohlenstoff. Als Hauptvorteil der Kreislaufwirtschaft sieht Professor Sundmacher den reduzierten Rohstoffbedarf bei hoher Recyclingquote. Er erläuterte den Beitrag von biologischen Rohstoffen zur Aufrechterhaltung des Kreislaufs und differenziert zwischen technischer Rezyklierbarkeit und Bioabbaubarkeit. Der Vortrag wurde von Astrid Butt verschriftlicht und für diese Working Paper-Ausgabe aufbereitet.In his presentation as a guest speaker for the bioeconomy online seminar at the Otto-von-Guericke University Magdeburg in June 2020, Professor Sundmacher introduced the contributions of bioeconomy, electro economy and circular economy as three complimentary pillars for a more sustainable economy toward the vision of a circular electrical economy and highlighted their respective potentials as well as their limitations. Professor Sundmacher claimed that bioeconomy is better suited to produce food, pharmaceutical compounds and chemicals than electricity and fuels. In his presentation, he explained the advantages of the electrical economy for the generation of electricity and production of hydrogen through wind and solar energy and the subsequent processing to e-fuels by combining hydrogen with carbon. The principal advantage of circular economy is the reduction in the use of raw materials, but it requires high recycling rates, according to Professor Sundmacher. He explained further the contribution of bio-based resources to the continuity of the loop and differentiates between technical recyclability and biodegradability. The presentation was transcribed and edited for this Working Paper issue by Astrid Butt

Non-linear frequency response analysis of the kinetics of electrochemical reactions: a case study – ferrocyanide oxidation kinetics

In general, electrochemical (EC) systems are non-linear, which means they respond nonlinearly to a frequency-dependent periodic input perturbation of high amplitude imposed around a steady-state. In addition, the kinetics of EC reactions are quite complex and different rivalling model presentations can be formulated for certain EC reaction. While standard electrochemical methods (steady-state and electrochemical impedance spectroscopy) showed low sensitivity towards the model discrimination, non-linear frequency response analysis (NLFRA) of EC kinetics can appear advantageous for this purpose. In this work, NLFRA is applied in experimental and theoretical study of ferrocyanide oxidation as a model EC reaction.Belgrade, Serbia, June 6-10, 2010Related to the published paper in the Proceedings of the Second Regional Symposium on Electrochemistry South-East Europe, [http://cer.ihtm.bg.ac.rs/handle/123456789/3539

Non-linear frequency response analysis of the kinetics of electrochemical reactions: a case study – ferrocyanide oxidation kinetics

In general, electrochemical (EC) systems are non-linear, which means they respond nonlinearly to a frequency-dependent periodic input perturbation of high amplitude imposed around a steady-state. In addition, the kinetics of EC reactions are quite complex and different rivalling model presentations can be formulated for certain EC reaction. While standard electrochemical methods (steady-state and electrochemical impedance spectroscopy) showed low sensitivity towards the model discrimination, non-linear frequency response analysis (NLFRA) of EC kinetics can appear advantageous for this purpose. In this work, NLFRA is applied in experimental and theoretical study of ferrocyanide oxidation as a model EC reaction.Belgrade, Serbia, June 6-10, 2010Related to the published paper in the Proceedings of the Second Regional Symposium on Electrochemistry South-East Europe, [http://cer.ihtm.bg.ac.rs/handle/123456789/3539

Fusion‐induced growth of biomimetic polymersomes: behavior of poly(dimethylsiloxane)‐poly(ethylene oxide) vesicles in Saline Solutions Under High Agitation

Abstract Giant unilamellar vesicles serve as membrane models and primitive mockups of natural cells. With respect to the latter use, amphiphilic polymers can be used to replace phospholipids in order to introduce certain favorable properties, ultimately allowing for the creation of truly synthetic cells. These new properties also enable the employment of new preparation procedures that are incompatible with the natural amphiphiles. Whereas the growth of lipid compartments to micrometer dimensions has been well established, growth of their synthetic analogs remains underexplored. Here, the influence of experimental parameters like salt type/concentration and magnitude of agitation on the fusion of nanometer‐sized vesicles made of poly(dimethylsiloxane)‐poly(ethylene oxide) graft copolymer (PDMS‐ g ‐PEO) is investigated in detail. To this end, dynamic light scattering, microscopy, and membrane mixing assays are employed, and the process at different time and length scales is analyzed. This optimized method is used as an easy tool to obtain giant vesicles, equipped with membrane and cytosolic biomachinery, in the presence of salts at physiological concentrations

Rational design of 3-D porous enzymatic electrodes for the production of gluconic acid in bioelectrochemical system

The focus of this research is on rational design of porous enzymatic electrodes as biocatalysts for gluconic acid production

Non-linear frequency response analysis of the kinetics of electrochemical reactions: a case study – ferrocyanide oxidation kinetics

In general, electrochemical (EC) systems are non-linear, which means they respond nonlinearly to a frequency-dependent periodic input perturbation of high amplitude imposed around a steady-state. In addition, the kinetics of EC reactions are quite complex and different rivalling model presentations can be formulated for certain EC reaction. While standard electrochemical methods (steady-state and electrochemical impedance spectroscopy) showed low sensitivity towards the model discrimination, non-linear frequency response analysis (NLFRA) of EC kinetics can appear advantageous for this purpose. In this work, NLFRA is applied in experimental and theoretical study of ferrocyanide oxidation as a model EC reaction.Belgrade, Serbia, June 6-10, 2010Related to the [http://cer.ihtm.bg.ac.rs/handle/123456789/3538

Making shared decision-making (SDM) a reality: protocol of a large-scale long-term SDM implementation programme at a Northern German University Hospital

Introduction: Shared decision-making (SDM) is not yet widely used when making decisions in German hospitals. Making SDM a reality is a complex task. It involves training healthcare professionals in SDM communication and enabling patients to actively participate in communication, in addition to providing sound, easy to understand information on treatment alternatives in the form of evidence-based patient decision aids (EbPDAs). This project funded by the German Innovation Fund aims at designing, implementing and evaluating a multicomponent, large-scale and integrative SDM programme-called SHARE TO CARE (S2C)-at all clinical departments of a University Hospital Campus in Northern Germany within a 4-year time period. Methods and analysis S2C tackles the aforementioned components of SDM: (1) training physicians in SDM communication, (2) activating and empowering patients, (3) developing EbPDAs in the most common/relevant diseases and (4) training other healthcare professionals in SDM coaching. S2C is designed together with patients and providers. The physicians' training programme entails an online and an in situ training module. The decision coach training is based on a similar but less comprehensive approach. The development of online EbPDAs follows the International Patient Decision Aid Standards and includes written, graphical and video-based information. Validated outcomes of SDM implementation are measured in a preintervention and postintervention evaluation design. Process evaluation accompanies programme implementation. Health economic impact of the intervention is investigated using a propensity-score-matched approach based on potentially preference-sensitive hospital decisions. Ethics and dissemination Ethics committee review approval has been obtained from Medical Ethics Committee of the Medical Faculty of the Christian-Albrechts-University Kiel. Project information and results will be disseminated at conferences, on project-hosted websites at University Hospital Medical Center Schleswig Holstein and by S2C as well as in peer-reviewed and professional journals