Applying endogenous learning models in energy system optimization

Conventional energy production based on fossil fuels causes emissions which contribute to global warming. Accurate energy system models are required for a cost-optimal transition to a zero-emission energy system, an endeavor that requires an accurate modeling of cost reductions due to technological learning effects. In this review, we summarize common methodologies for modeling technological learning and associated cost reductions. The focus is on learning effects in hydrogen production technologies due to their importance in a low-carbon energy system, as well as the application of endogenous learning in energy system models. Finally, we present an overview of the learning rates of relevant low-carbon technologies required to model future energy systems.Comment: review paper: main article (11 pages), appendices (8 pages), references (4 pages

A case report of recurrent acute myocardial infarction and cardiac arrest due to aortic dissection secondary to IgG4-related aortitis

Occlusion of the right coronary artery is a relatively rare complication of type A aortic dissection and an example of type 2 myocardial infarction (MI) as well but when it occurs, it may have a fatal result for the patient. Aortic pseudoaneurysms are local type A dissections with a restricted extent in which the majority of the aortic wall has been breached and luminal blood is held in only by a thin rim of the remaining wall, mainly purely the adventitia. They typically occur from iatrogenic trauma by interventional procedures or previous cardiac surgery. We present a case of a 56 years old patient who suffered an acute functional MI due to such pseudoaneurysm formed in the context of an undiagnosed aortitis. The etiology remained unclear until the surgical aortic prosthesis was deemed necessary, finding chronic IgG4 infiltrates in the aortic tissue. To our knowledge, this is the first case of IgG4-related aortitis causing functional MI and cardiogenic shock

SCARLET – A European Effort to Develop HTS and MgB2 Based MVDC Cables

Superconducting cables have been proven in a variety of pilot projects and utility installations, demonstrating several of their advantages, including compact size and low energy losses, which can make the technology economically attractive for certain applications. It is clear though that different applications impose different requirements and challenges, but also opportunities for the cables. An interesting application is high-power DC transfer at medium voltage (MVDC). The high-current capability of the superconductor allows for a reduction in voltage while maintaining or increasing the power transfer level. In this way, one MVDC superconducting cable can replace one or more conventional high-voltage DC cables. In the European project SCARLET (Superconducting cables for sustainable energy transition), two types of MVDC cables will be developed, one based on HTS and one on MgB2 materials. Additionally, protection requirements will be considered, including the development of a modular DC fault current limiter for 10 kA. A main motivation for the development is the elimination of costly high-voltage converter stations when going from high to medium voltage, e.g., for offshore wind power plants. Another feature is the combined hydrogen and electricity transmission from generation sites to industry or mobility end users. This paper describes the superconducting MVDC cable concept as well as the main challenges and research needed to develop and type test the cables.SCARLET – A European Effort to Develop HTS and MgB2 Based MVDC CablesacceptedVersio

Game over. Neustart! : Das Buch zum vierten Kongress von Attac, BUND, Evangelischer Entwicklungsdienst, Greenpeace, Heinrich Böll Stiftung in Kooperation mit dem Wuppertal Institut für Klima, Umwelt, Energie

Was sind die Alternativen zur vorherrschenden Wachstumsideologie und wie lassen sich die Rechte der Menschen und der Umwelt wahren? Wie lässt sich der globale Casino-Kapitalismus zähmen? Was müssen wir an unserer Lebens- und Wirtschaftsweise ändern, um eine Klimakatastrophe noch abzuwenden und den Ressourcenraubbau zu beenden? Unter dem Motto "Game Over. Neustart!" wurde beim vierten Kongress "McPlanet.com" vom 24. bis 26. April 2009 in Berlin mit internationalen Referent(inn)en über die Brennpunkte der aktuellen Krisen und Ideen und Strategien zu ihrer Lösung diskutiert - auf Panels, Foren und in über 100 Workshops

Applying Endogenous Learning Models in Energy System Optimization

Conventional energy production based on fossil fuels causes emissions that contribute to global warming. Accurate energy system models are required for a cost-optimal transition to a zero-emission energy system, which is an endeavor that requires a methodical modeling of cost reductions due to technological learning effects. In this review, we summarize common methodologies for modeling technological learning and associated cost reductions via learning curves. This is followed by a literature survey to uncover learning rates for relevant low-carbon technologies required to model future energy systems. The focus is on (i) learning effects in hydrogen production technologies and (ii) the application of endogenous learning in energy system models. Finally, we discuss methodological shortcomings of typical learning curves and possible remedies. One of our main results is an up-to-date overview of learning rates that can be applied in energy system model

Mechanical Forces Impeding Exocytotic Surfactant Release Revealed by Optical Tweezers

The release of surfactant from alveolar type II cells is essential to lower the surface tension in the lung and to facilitate inspiration. However, the factors controlling dispersal and diffusion of this hydrophobic material are still poorly understood. Here we report that release of surfactant from the fused vesicle, termed lamellar body (LB), resisted mechanical forces applied by optical tweezers: At constant trapping force, the probability to expand LB contents, i.e., to “pull” surfactant into the extracellular fluid, increased with time after LB fusion with the plasma membrane, consistent with slow fusion pore expansion in these cells. Elevations of the cytoplasmic Ca(2+) concentration ([Ca(2+)](c)) had a similar effect. Inasmuch as surfactant did not disintegrate in the extracellular space, this method permitted for the first time the determination of elastic and recoil properties of the macromolecular complex, yielding a spring constant of ∼12.5 pN/μm. This is the first functional evidence that release of hydrophobic material is mechanically impeded and occurs in an “all-or-none” fashion. This mode of release is most probably the result of cohesive forces of surfactant, combined with adhesive forces and/or retaining forces exerted by a constrictive fusion pore acting as a regulated mechanical barrier, withstanding forces up to 160 pN. In independent experiments equiaxial strain was exerted on cells without optical tweezers. Strain facilitated surfactant release from preexisting fused vesicles, consistent with the view of mechanical impediments during the release process, which can be overcome by cell strain

Ultrasound-induced reorientation for multi-angle optical coherence tomography

Abstract Organoid and spheroid technology provide valuable insights into developmental biology and oncology. Optical coherence tomography (OCT) is a label-free technique that has emerged as an excellent tool for monitoring the structure and function of these samples. However, mature organoids are often too opaque for OCT. Access to multi-angle views is highly desirable to overcome this limitation, preferably with non-contact sample handling. To fulfil these requirements, we present an ultrasound-induced reorientation method for multi-angle-OCT, which employs a 3D-printed acoustic trap inserted into an OCT imaging system, to levitate and reorient zebrafish larvae and tumor spheroids in a controlled and reproducible manner. A model-based algorithm was developed for the physically consistent fusion of multi-angle data from a priori unknown angles. We demonstrate enhanced penetration depth in the joint 3D-recovery of reflectivity, attenuation, refractive index, and position registration for zebrafish larvae, creating an enabling tool for future applications in volumetric imaging

Ca2+ entry is essential for cell strain-induced lamellar body fusion in isolated rat type II pneumocytes

Using a new equibiaxial strain device, we investigated strain-induced Ca2+ signals and their relation to lamellar body (LB) exocytosis in single rat alveolar type II (AT II) cells. The strain device allows observation of single cells while inducing strain to the entire substratum. AT II cells tolerated high strain amplitudes up to 45% increase in cell surface area (Delta CSA) without release of lactate dehydrogenase or ATP. Strain exceeding a threshold of approximately 8% Delta CSA resulted in a transient rise of the cytoplasmic Ca2+ concentration in some cells. Higher strain levels increased the fraction of Ca2+-responding cells. The occurrence of strain-induced Ca2+ signals depended on cell-cell contacts, because lone cells (i.e., cells without cell-cell contacts) did not exhibit Ca2+ signals. Above threshold, the amplitude of the Ca2+ signal as well as the number of stimulated LB fusions correlated well with the amplitude of strain. Furthermore, stimulated LB fusions occurred only in cells exhibiting a Ca2+ signal; 50 microM Gd3+ in the bath affected neither Ca2+ signals nor fusions. Intracellular Ca2+ release was triggered at higher strain amplitudes and inhibited by thapsigargin. Removal of bath Ca2+ completely inhibited Ca2+ signals and fusions. We conclude that strain of AT II cells stimulates a Ca2+ entry pathway that is highly sensitive to strain and a prerequisite for subsequent Ca2+ release. Both mechanisms result in a graded response of fusions to strain. Our data also allow us to introduce the term "effective strain" as the physiologically relevant portion of the strain amplitude