Cold Spray metal powder deposition with 9 %Cr-steel applied for the HCPB First Wall fabrication: Proof of concept and options for ODS steel processing

At the KIT a hybrid manufacturing concept for nuclear fusion First Walls is developed combining aspects of conventional and Additive Manufacturing (AM) technologies. The state of the art for ITER does not cover all specifications of a DEMO relevant First Wall. Thus, additional R&D-work has been initiated in terms of manufacturing. The AM technology basis used in the presented process combination is Cold Spray metal powder deposition applied in alternation with machining including the feature of filling grooves temporarily with a water-soluble granulate for creation of closed channels and cavities. Thus, the technology provides the option to manufacture shells with a thin gas tight membrane on top of previously machined structures. This membrane is used as pressure seal and makes the joining of shells by Hot Isostatic Pressing (HIP) into one monolithic body possible. This paper describes the manufacturing process and recalls differences and common aspects with regard to conventional concepts of First Wall manufacturing. The achievement of Technology Readiness Level TRL 3 by mechanical qualification and comparison of the results to other HIP joint experiments is also demonstrated. Finally, an outlook is given concerning integration options of the technology into manufacturing of shells with cooling channel structures using Oxide Dispersion Strengthened (ODS) materials

Specific Ion–Protein Interactions Influence Bacterial Ice Nucleation

Ice nucleation-active bacteria are the most efficient ice nucleators known, enabling the crystallization of water at temperatures close to 0 °C, thereby overcoming the kinetically hindered phase transition process at these conditions. Using highly specialized ice-nucleating proteins (INPs), they can cause frost damage to plants and influence the formation of clouds and precipitation in the atmosphere. In nature, the bacteria are usually found in aqueous environments containing ions. The impact of ions on bacterial ice nucleation efficiency, however, has remained elusive. Here, we demonstrate that ions can profoundly influence the efficiency of bacterial ice nucleators in a manner that follows the Hofmeister series. Weakly hydrated ions inhibit bacterial ice nucleation whereas strongly hydrated ions apparently facilitate ice nucleation. Surface-specific sum-frequency generation spectroscopy and molecular dynamics simulations reveal that the different effects are due to specific interactions of the ions with the INPs on the surface of the bacteria. Our results demonstrate that heterogeneous ice nucleation facilitated by bacteria strongly depends upon the nature of the ions, and specific ion–protein interactions are essential for the complete description of heterogeneous ice nucleation by bacteria.This work was financially supported by the MaxWater initiative of the Max Planck Society and the Max Planck Graduate Center with the Johannes Gutenberg-Universität Mainz. We thank Arpa Hudait and Valeria Molinero for providing the reconstructed INP structure file. A.Y.Y. and K.F.D. gratefully acknowledge funding through the “Plus 3” program of the Boehringer Ingelheim Stiftung. Open access funding enabled and organized by Projekt DEAL.Ye

Risk governance in organizations

Dieses Buch dokumentiert 10 Jahre Risk-Governance-Forschung an der Universität Siegen. In 50 Beiträgen reflektieren Forscher und Praktiker Risk Governance vor dem Hintergrund ihrer eigenen Forschungen und/oder Erfahrungen und geben jeweils einen Entwicklungsimpuls für die Zukunft der Risk Governance. Das Buch zeigt die große Bandbreite und Tiefe des Forschungsgebietes auf und diskutiert Grundannahmen, Implementierungsfragen, die Rolle der Risk Governance als Transformationsmotor, ihre Wirkung in den verschiedenen betrieblichen Funktionen, Entwicklungsperspektiven und den Beitrag der Risk Governance zu einer nachhaltigen Ausrichtung von Unternehmen.This book documents 10 years of risk governance research at the University of Siegen. In 50 contributions, researchers and practitioners reflect on risk governance against the background of their own research and/or experience and provide a development impetus for the future of risk governance. The book shows the wide range and depth of the research field and discusses basic assumptions, implementation issues, the role of risk governance as transformation engine, its impact in the various operational functions, development perspectives, and the contribution of risk governance to a sustainable orientation of companies

the PROTECTOR project

vulnerable traffic participants

Automated delineation of debris-covered glaciers based on ASTER data

Large areas of the glacier tongues at Mt. Everest are heavily covered by supraglacial debris. This hampers the automated mapping of the actual ice snout by means of spaceborne imagery due to the similar spectral signal of the surrounding debris. The most significant features which differentiate the glaciers are the typical surface characteristics like a rough surface or “cryokarst” and a number of ablation ponds. At a first glance the outline of these debris-covered glaciers seems to be stable. Looking in detail at these glaciers using multitemporal space imagery it is obvious that recent glacier shrinkage results in an increasing debris coverage and an increasing number and, hence, area of supra-glacial lakes. In addition, the surface, especially at the very distal part of the glacier, looks smoother and shows no significant indications for movement. Hence, presently ASTER stereo-images represent an ideal tool to develop an automated way of outlining the ice extents of the active and inactive glacier. Combining ASTER’s thermal information with various shape parameters derived from stereo models, both the actual glacier beds and the marginal moraines could be outlined. Mainly due to the resolution of the ASTER DEM (30 m) this concept is only promising for large glaciers such as the Khumbu Glacier. In future, when high resolution DEMs will be available, the accuracy will be sufficient for a fully automated glacier monitoring, including smaller glaciers

Antihypertensive Treatment in Kidney Transplant Recipients—A Current Single Center Experience

Arterial hypertension affects the survival of the kidney graft and the cardiovascular morbidity and mortality of the recipient after kidney transplantation (KTx). Thus, antihypertensive treatment is necessary for a vast majority of these patients. Long-term data on antihypertensive drugs and their effects on allograft function after KTx is still limited, and further investigation is required. We retrospectively analyzed a cohort of 854 recipients who received a kidney transplant at our transplant center between 2007 and 2015 with regard to antihypertensive treatment and its influence on graft function and survival. 1-y after KTx, 95.3% patients were treated with antihypertensive therapy. Of these, 38.6% received mono- or dual-drug therapy, 38.0% received three to four drugs and 8.1% were on a regimen of ≥5 drugs. Beta-blockers were the most frequently used antihypertensive agents (68.1%). Neither the use of angiotensin-converting enzyme inhibitor/angiotensin receptor blockers (51.9%) and calcium channel blockers (51.5%), nor the use the use of loop diuretics (38.7%) affected allograft survival. Arterial hypertension and the number of antihypertensive agents were associated with unfavorable allograft outcomes (each p < 0.001). In addition to the well-known risk factors of cold ischemic time and acute rejection episodes, the number of antihypertensive drugs after one year, which reflects the severity of hypertension, is a strong predictor of unfavorable allograft survival

Inhibition of Bacterial Ice Nucleators Is Not an Intrinsic Property of Antifreeze Proteins

Cold-adapted organisms use antifreeze proteins (AFPs) or ice-nucleating proteins (INPs) for the survival in freezing habitats. AFPs have been reported to be able to inhibit the activity of INPs, a property that would be of great physiological relevance. The generality of this effect is not understood, and for the few known examples of INP inhibition by AFPs, the molecular mechanisms remain unclear. Here, we report a comprehensive evaluation of the effects of five different AFPs on the activity of bacterial ice nucleators using a high-throughput ice nucleation assay. We find that bacterial INPs are inhibited by certain AFPs, while others show no effect. Thus, the ability to inhibit the activity of INPs is not an intrinsic property of AFPs, and the interactions of INPs and different AFPs proceed through protein-specific rather than universal molecular mechanisms

Cold Spray metal powder deposition with 9 %Cr-steel applied for the HCPB First Wall fabrication: Proof of concept and options for ODS steel processing

At the KIT a hybrid manufacturing concept for nuclear fusion First Walls is developed combining aspects of conventional and Additive Manufacturing (AM) technologies. The state of the art for ITER does not cover all specifications of a DEMO relevant First Wall. Thus, additional R&D-work has been initiated in terms of manufacturing. The AM technology basis used in the presented process combination is Cold Spray metal powder deposition applied in alternation with machining including the feature of filling grooves temporarily with a water-soluble granulate for creation of closed channels and cavities. Thus, the technology provides the option to manufacture shells with a thin gas tight membrane on top of previously machined structures. This membrane is used as pressure seal and makes the joining of shells by Hot Isostatic Pressing (HIP) into one monolithic body possible. This paper describes the manufacturing process and recalls differences and common aspects with regard to conventional concepts of First Wall manufacturing. The achievement of Technology Readiness Level TRL 3 by mechanical qualification and comparison of the results to other HIP joint experiments is also demonstrated. Finally, an outlook is given concerning integration options of the technology into manufacturing of shells with cooling channel structures using Oxide Dispersion Strengthened (ODS) materials