Collaborative Research Center Research Articles

Development of a Stainless Austenitic Nitrogen-Alloyed CrMnNiMo Spring Steel

The generation of a nickel-reduced, stainless spring steel strip with a thickness of 0.2 mm, producible under industrial conditions, is the aim of a transfer project together with the Institute of Metal Forming/TU BAF and the Auerhammer Metallwerk GmbH within the DFG Collaborative Research Centre (CRC) 799. The spring steel strip should exhibit a tensile strength of ≥1700 MPa in work-hardened and partitioned state. The mechanical and corrosive properties of the steel strip should be equal or better than those given for 1.4310 steel (AISI 301). The article presents the results of laboratory alloys focused on the design of steel strips, which meet the requirements for a cost-effective production. The results presented relate to steel design, microstructure formation, temperature-dependent mechanical properties, and corrosion resistance. Four alloys of the type X5CrMnNiMoN16-x-4 with manganese contents of approximately 2 to 6 wt.-percent were investigated. The austenitic steel X5CrMnNiMoN16-4-4 with TRIP/TWIP effect was selected for deformation and partitioning treatments. Its deformation-induced α’-martensite formation significantly contributes to the work hardening of the steel. A short-time annealing treatment (partitioning) further increases the strength properties.

Integration of LCA in the Planning Phases of Adaptive Buildings

The high consumption of resources in the building industry requires a significant reduction of material in buildings and consequently a reduction of emissions over all phases of the life cycle. This is the aim of the Collaborative Research Centre 1244 Adaptive Skins and Structures for the Built Environment of Tomorrow, funded by the German Research Foundation (DFG), which addresses research on the development and integration of adaptive systems in building structures and skins. New approaches in building planning are required for the implementation of adaptive buildings. Therefore, a multidisciplinary team from various fields such as architecture, civil and mechanical engineering, and system dynamics is necessary. The environmental impacts of the whole life cycle have to be considered for an integral planning process for adaptive buildings right from the beginning. For the integration of the Life Cycle Assessment (LCA), four temporal and content-related interfaces were identified in the planning process. Inputs and outputs of the LCA were defined for the relevant planning stages in order to enable the greatest possible benefit for the planners and to minimize the environmental impacts as far as possible. The result of the research work is a methodology that can be used in the future to reduce life cycle-related environmental impacts in the planning process of adaptive buildings (ReAdapt).

Investigation of the joining zone displacement of cross-wedge rolled serially arranged hybrid parts

Within the Collaborative Research Centre (CRC) 1153 “Tailored Forming “the manufacturing of hybrid bulk components is investigated. Therefore, a process chain consisting of joining, forming, milling and quality control has been established by multiple subprojects. Within subproject B1 of the CRC forming of hybrid parts by the incrementally forming cross-wedge rolling (CWR) process is investigated. The superior aim is to determine process limits and capabilities, when forming parts consisting of different materials joined by varying technologies. In this paper, the investigation of cross-wedge rolling of serially arranged hybrid parts made of steel and aluminium is described. The focus of the research presented in this publication is the displacement of the joining zone of hybrid parts due to the cross-wedge rolling process. Therefore, finite element simulations have been developed, that allow the investigations of hybrid solid components. After simulation of various variations of the cross-wedge rolling process, i.e. differently shaped tools and forming velocities, experimental trials were carried out with identical parameter sets. A comparison of simulation and experiment, showed that the simulation model is capable of describing the cross-wedge rolling process of hybrid parts. The standard deviation of the displacement of the joining zone between simulation and experimental trials is 8.8% with regard to all investigated cases.

Method Toolbox for the Multidisciplinary Planning and Development of Adaptive Buildings

AbstractAdaptive buildings constitute an interdisciplinary approach for realizing the next generation of buildings in order to reduce the immense material requirements and energy demand throughout all lifecycle phases. Based on a novel cooperation between the disciplines of Architecture and Civil and Mechanical Engineering, adaptive support structures and skins are developed within the Collaborative Research Centre SFB 1244. A holistic planning process is required in order to reduce the high complexity and achieve a goal-oriented procedure during the planning of such buildings and the development of integrated systems.Part of this research is the development of new specific and the transfer of established methods from different disciplines. The experience gained during the planning of an adaptive, high-rise demonstrator building within the research project has shown that the methods for application must be provided in the form of a method toolbox to present their purpose, application time and results within the planning team. Based on the examination of existing method toolkits, this paper focuses on the development of an approach while considering context-specific requirements.

Defensio oder Die Kunst des Invektierens im Oberrheinischen Humanismus

Summary Defensio or The Art of Disparagement in the Upper-Rhenish Humanism In the first years of the 16th century two scholars from the Alsatian province, secular priest Jakob Wimpfeling and Franciscan Thomas Murner, the latter one generation younger than the former, started a quarrel in Strasbourg. Quickly, their friends and students, then the city council, and finally even King Maximilian I got drawn into the polemical debate. At first sight the controversial topic was only a highly charged issue in politically troubled times: Had the Alsace region and its capital always belonged to Germany or had they been part of France at some time in the past? But it was also a quarrel about the educational sovereignty. This was an issue important to humanists. Secular ond ordinary priests hotly debated the topic not only in Strasbourg, but also elsewhere. The literary feud involved not only arguments, but also sharp personal attacks, offences and defamations. Several publications included disparaging letters, poems, treatises and pictures which often hardly bore any reference to the issue in question. The question arises why humanists, who are generally thought to be concerned with language and education, resorted to such drastic and defamatory means in their personal conflicts. The paper addresses this question with the help of the theories and methods currently employed by the Collaborative Research Centre Dresden with the title „Invectivity“. It analyzes the constellations of the controversy, examines the dynamics and escalations of their process, and traces the emotions of those involved. This will deepen our understanding about the operations of social demarcation and the mechanisms of group formation among humanists and concomitantly the fundamental social potential for conflict.

The concept of socio-environmental transformations in prehistoric and archaic societies in the Holocene: An introduction to the special issue

Transformations of human societies and environments are closely interwoven. Due to improved possibilities of paleoecological reconstruction and archaeological methods, we are now in a position to empirically collect detailed data from a variety of records. The Collaborative Research Centre 1266 ‘Scales of Transformation’ has developed a concept in which both deductive and inductive transformation dimensions are compared on different temporal and spatial scales. This concept includes the connection between the environmental and social spheres, which are often inseparable. Accordingly, a holistic principle of socio-environmental research is developed, which is exemplified by the contributions to this special issue of The Holocene.

Evaluating university industry collaborative research centers

This research provides performance metrics for cooperative research centers that enhance translational research through partnerships formed by government, industry and academia. Centers are part of complex ecosystems and vary greatly in the type of science conducted, organizational structures and expected outcomes. The ability to realize their objectives depends on transparent measurement systems to assist in decision making in research translation. We introduce a hierarchical decision model that uses both quantitative and qualitative metrics. A generalizable model is developed based upon program goals. The results are validated through consultation with experts. The method is illustrated using data from the National Science Foundation's industry/university cooperative research center (IUCRC) program. The methodology provides a basis for a generalizable model and measurement system to compares performance of university science and engineering focused research centers supported by industry and government.

The role of university‐industry research centers in embedding foreign subsidiaries: Insights from automotive research and development in Ontario

AbstractRegionally embedded foreign subsidiaries have an advantage over disembedded ones. The ability to draw on local knowledge networks to create differentiating capabilities can enhance the subsidiary's influence within the multinational enterprise. A subsidiary's power is shaped by its control over external resources or skills the parent company depends on to develop new products. These local relationships are then used to bargain for further mandates, sometimes in competition with sister subsidiaries. One way in which foreign subsidiaries can deepen their connections with the local context is by collaborating in their innovative efforts with university‐based collaborative research centers (CRCs). I argue that CRCs are not a panacea when it comes to embedding the subsidiaries of foreign multinational enterprises (MNEs). A review of the literature helps identify the subsidiary‐parent relationship and industry‐academia conflicts of interest as obstacles to the development of productive relationships between subsidiaries and academia. I draw on evidence from three Ontario CRCs, with different scientific focus and stakeholders and analyze how these factors shape their behavior. The study shows that long‐term CRCs‐subsidiary relationships can be challenging to establish. This is because subsidiaries remain tightly controlled by their parent companies and cannot get access to the resources necessary to pursue ambitious innovation projects. It is also challenging for subsidiaries to form long‐term relationships with CRC researchers, who prioritize other goals such as training skilled personnel and continuing their research agenda. CRCs where 1) subsidiaries have a strong bargaining position within the MNE, and 2) academic expertise is aligned with industry needs have a greater chance to contribute to future MNE embeddedness.

Immunotherapy for cardiovascular disease.

The outcomes of the Canakinumab Anti-inflammatory Thrombosis Outcome Study (CANTOS) trial have unequivocally proven that inflammation is a key driver of atherosclerosis and that targeting inflammation, in this case by using an anti-interleukin-1β antibody, improves cardiovascular disease (CVD) outcomes. This is especially true for CVD patients with a pro-inflammatory constitution. Although CANTOS has epitomized the importance of targeting inflammation in atherosclerosis, treatment with canakinumab did not improve CVD mortality, and caused an increase in infections. Therefore, the identification of novel drug targets and development of novel therapeutics that block atherosclerosis-specific inflammatory pathways and exhibit limited immune-suppressive side effects, as pursued in our collaborative research centre, are required to optimize immunotherapy for CVD. In this review, we will highlight the potential of novel immunotherapeutic targets that are currently considered to become a future treatment for CVD.

Simulation-Aided Process Chain Design for the Manufacturing of Hybrid Shafts

Abstract Researchers of the Collaborative Research Centre CRC 1153 are investigating novel process chains to manufacture function-adapted and lightweight machine components. In each step of the process chain, numerical simulation tools are utilised in the process design to take into account locally specific material behaviour under particular processing conditions. In this paper, solution approaches associated with the modelling of manufacturing processes are presented.

Simulation Assisted Process Development for Tailored Forming

Transport industry faces challenges steadily due to rising fuel costs and stricter regulations for the emission of air pollutants. Technological developments that reduce fuel consumption are necessary for sustainable and resource-efficient transport. Innovative production technologies utilising multi-material designs come to the fore in an attempt to fabricate lightweight products with extended functionality. Departing from this motivation, novel process chain concepts for the manufacturing of bi-material forged products are being researched at the Leibniz Universität Hannover in the context of the Collaborative Research Centre (CRC) 1153. The developed technology is referred as Tailored Forming and deals with the deformation and subsequent processing of joined hybrid workpieces to produce application-oriented products. Deformation processes are carried out at elevated temperatures for thermomechanical treatment of the joining zone properties. Researchers make use of numerical simulation in each step in the process chains. This paper explains the challenges associated with induction heating and impact extrusion of bi-material forging billets and presents our solution approaches with the aid of numerical modelling. Experimental validation results and analysis of deformed workpieces are also shown.

TRIP‐Matrix‐Composites

Composite materials represent a fascinating class of materials, as new properties can be achieved by combining different phases. Challenging composite materials based on high-alloy austenitic stainless steels and zirconia are being researched at the Technische Universität Bergakademie Freiberg, Germany, within a major research programme. In Collaborative Research Centre 799, which has been funded by the German Research Foundation (Deutsche Forschungsgemeinschaft DFG) since 2008, new manufacturing methods are being explored, new steel compositions are being developed, microstructures and properties are being analysed and new approaches to material modelling are being established. For further information, readers are referred to the website tu-freiberg.de/forschung/sfb799. The fascination of the new composite materials results from the ability of both phases to martensitic phase transformations. Depending on the chemical composition and temperature, the steels used as matrix for the composites show either the transformation of the fcc structure into the bcc α′-martensite and thus the TRIP effect (Transformation-Induced Plasticity), or a deformation-induced twin formation (TWIP effect). The MgO partially stabilized zirconia used also exhibits a martensitic phase transformation from the tetragonal phase to the monoclinic structure. Thus, the two phases can interact in a complex way during mechanical loading. In the following articles, current research results are presented. They range from material production and the design of the steels to the analysis of the deformation mechanisms. First, the production of N-alloyed steel powders by inert gas atomization is treated (Korobeinikov et al.). Furthermore, the powder metallurgical production of composite materials via sintering (Baumgart et al.), spark plasma sintering (Radajewski et al.) and the production of composite beads via a slurry-based process (Oppelt et al.) are discussed. In further contributions, the hot forming of N-alloyed austenitic steels (Nam et al.) and the formation and dissolution of carbides in Al alloyed steels are investigated (Mola et al.). An insight into the deformation mechanisms is provided by in situ synchrotron diffraction (Ullrich et al.) and nanoindentation (Lehnert et al.). An important question for the martensitic phase transformation of the steel is the thermodynamic driving force for the γ-α′ phase transformation (Hauser et al.). Since it has been shown that Ti has positive effects on the phase boundaries, the equilibrium phases in the zirconia-titania-magnesia system are investigated (Saenko et al.). Furthermore, a new process for the production of (ultra)high-strength steels of the 3rd generation, quenching-deformation-partitioning, is discussed (Wendler et al.). For steels produced over a similar route (quenching and partitioning) the cyclic properties and fatigue life are presented (Droste et al.). Further work shows the behaviour of austenitic stainless steels under axial-torsional loading (Krause et al.) and crack growth under biaxial-planar fatigue loading (Wolf et al.). Finally, the electrochemical corrosion behaviour is studied using electrochemical noise and acoustic emission analysis (Kietov et al.). In order to enable future processing of the new composite materials, joining using electron beam technologies (Halbauer et al.) and simulation of the joining process are considered (Borrmann et al.). These articles present aspects of the current research work. Of course it is not possible to give a complete overview. Therefore, the readers are referred to the further literature. Finally, we would like to thank the German Research Foundation for the financial support of the work within SFB 799. Horst Biermann

Particle methods in natural science and engineering

This special topics issue offers a broad perspective on the recent developments and reviews of state-of-the-art particle methods in science and engineering applications. This issue grew out of contributions delivered during the closing conference of the Collaborative Research Centre (CRC) 716 that for the last twelve years was contributing important works to the area of “dynamical simulations of systems with large particle numbers”. Since particle methods are present in many fields of science and engineering, the papers collected here span a considerable range of subjects and questions, but they also illustrate numerous connections to both fundamental science and technological/industrial applications. In addition reviews display the current state of three software packages that have been developed in this CRC in the area of simulations and visualization.

Interactive visualization of biomolecules’ dynamic and complex properties

In this paper, we review the advances in molecular visualization over the last 12 years and put the development of the community in context with our own efforts in the DFG Collaborative Research Center (CRC) 716. This includes advances in the field of molecular surface computation and rendering, interactive extraction of protein cavities, and comparative visualization for biomolecules. Our main focus was on the development of methods that assist the interactive and explorative visual analysis of large, dynamic molecular data sets on single desktop computers. To meet this goal, we often developed GPU-accelerated algorithms, which is in line with the general research direction of the field. Over the last years, we made seminal contributions to the field of molecular visualization, which partially still constitute the state of the art development or provided the basis for follow-up works.

A decade of particle-based scientific visualization

In this manuscript, we review the evolution of atomistic visualization over the last 12 years and put the development of the community in context with our own efforts within the DFG collaborative research center 716. The goal is to provide a comprehensive summary of all relevant work that has been conducted under the auspices of project D.3. In this project, we focused on the visualization and analysis of particle-based data sets, and on how to bring these visualizations onto the workstation of domain scientists without the need for a large rendering infrastructure. We discuss how our decisions and goals evolved over time and show the success stories and publications. Finally, we give an outlook on the challenges that still require additional research and to which extent the requirements and constraints of current research have changed the way visualization works after these 12 years.

Manufacturing and Evaluation of Multi-Material Axial-Bearing Washers by Tailored Forming

Components subject to rolling contact fatigue, such as gears and rolling bearings, are among the fundamental machine elements in mechanical and vehicle engineering. Rolling bearings are generally not designed to be fatigue-resistant, as the necessary oversizing is not technically and economically marketable. In order to improve the load-bearing capacity, resource efficiency and application possibilities of rolling bearings and other possible multi-material solid components, a new process chain was developed at Leibniz University Hannover as a part of the Collaborative Research Centre 1153 “Tailored Forming”. Semi-finished products, already joined before the forming process, are used here to allow a further optimisation of joint quality by forming and finishing. In this paper, a plasma-powder-deposition welding process is presented, which enables precise material deposition and control of the welding depth. For this study, bearing washers (serving as rolling bearing raceways) of a cylindrical roller thrust bearing, similar to type 81212 with a multi-layer structure, were manufactured. A previously non-weldable high-performance material, steel AISI 5140, was used as the cladding layer. Depending on the degree of forming, grain-refinement within the welded material was achieved by thermo-mechanical treatment of the joining zone during the forming process. This grain-refinements lead to an improvement of the mechanical properties and thus, to a higher lifetime for washers of an axial cylindrical roller bearing, which were examined as an exemplary component on a fatigue test bench. To evaluate the bearing washers, the results of the bearing tests were compared with industrial bearings and deposition welded axial-bearing washers without subsequent forming. In addition, the bearing washers were analysed micro-tribologically and by scanning acoustic microscopy both after welding and after the forming process. Nano-scratch tests were carried out on the bearing washers to analyse the layer properties. Together with the results of additional microscopic images of the surface and cross-sections, the causes of failure due to fatigue and wear were identified.

Down-Regulation of Cell Membrane Localized NTCP Expression in Proliferating Hepatocytes Prevents Hepatitis B Virus Infection

Background: Hepatocyte proliferation could result in the loss of covalently closed circular DNA (cccDNA) and the emergence of cccDNA-cleared nascent hepatocytes, which appear refractory to hepatitis B virus (HBV) reinfection with unknown mechanism(s). This study aims to uncover the underlying molecular mechanism(s) and its related clinical significance on HBV reinfection resistance of proliferating hepatocytes. Methods: The transcriptional inhibition of Sodium taurocholate cotransporting polypeptide (NTCP) expression in proliferating hepatocytes and impact of NTCP protein levels on HBV infection were assayed both in vivo and in vitro. The clinical significance of NTCP down-regulation was explored in a cohort of 68 HBeAg-positive chronic hepatitis B (CHB) patients. Findings: Arresting HepG2-NTCP-tet cells in G0/G1 phase obviously up-regulated NTCP cell membrane expression and thus facilitated HBV infection in vitro. In liver-humanized mice, HBV reinfection occurred only after most hepatocytes had stopped proliferating and cell membrane expression of NTCP returned to normal. In patients, lower NTCP protein expression was correlated well with higher levels of hepatocyte proliferation and less HBsAg expression in HBV-related focal nodular hyperplasia (FNH) tissues. Clinically, significantly lower NTCP protein expression was correlated with more active hepatocyte proliferation in CHB patients with severe active necroinflammation and better antiviral treatment outcome. Mechanistically, p53, cyclin D1, S-phase kinase associated protein 2 and interleukin-6 could transcriptionally down-regulate NTCP expression. Interpretation: Within the milieu of hepatocyte proliferation, lower NTCP expression level renders nascent hepatocytes resistant to HBV reinfection. This may accelerate virus clearance during immune-mediated cell death and compensatory proliferation of survival hepatocytes. Funding Statement: This study was supported by grants from National Science and Technology Major Project of the Ministry of Science and Technology of China (2017ZX10202203, 2017ZX10302201, 2017ZX10202202), the National Natural Science Foundation of China (81672013) and the German Research Foundation (DFG, Collaborative Research Centre SFB-841: A5). Among them, the German Research Foundation (DFG, Collaborative Research Centre SFB-841: A5) supported the studies involved liver-humanized mice. The National Science and Technology Major Project of the Ministry of Science and Technology of China (2017ZX10202203, 2017ZX10302201, 2017ZX10202202), and the National Natural Science Foundation of China (81672013) supported the evolving of the other experiments. Declaration of Interests: All authors have no conflict of interest to disclose. Ethics Approval Statement: The animal experiments involving humanized mice were approved by the City of Hamburg, Germany (G118/16), conducted in accordance with the European Communities Council Directive (86/EEC). The other animals involved in the study were approved by the Bioethics Committees of Peking University, the reference number is LA2018181. The clinical data involved in the study was approved by the Bioethics Committees of Peking University at February 27th, 2018.

Friction and wear investigations on single chain joints

The tribological behavior of machine elements is mostly influenced by the contact surfaces and the lubricant, especially for transient conditions and mixed or boundary friction. Both can be found in chain joint contacts. Chains of different types and structural designs are commonly used in drive and convey applications as well as timing drives of combustion engines, e. g. bush, roller and silent chains. The critical operating time is fundamentally limited by the wear inside the chain joints. Especially for timing chains, only a small elongation of 0.5% is admissible. Optimization of component surfaces, which includes reduction of friction and wear, is the primary goal of the German Research Foundation (DFG) Collaborative Research Centers 926 “Microscale Morphology of Component Surfaces (MICOS)”. Potential of timing chain components with modified surfaces are the focus of present research. Chain wear test rigs for investigation of entire chain drives require a considerable number of modified parts, which is not suitable for systematic tests. Therefore, a chain joint tribometer was developed and commissioned to close the gap between model tests on standard tribometers and investigations on whole chain drives by focusing on a single chain joint. Realistic load conditions were applied to the tested chain segment using a highly-dynamic engine (rotation) and linear actor (tension force) to investigate wear and friction on a single chain joint. The measurement system allows for online wear and friction detection.

A Transdisciplinary Approach is Essential to Community-based Research with American Indian Populations.

Social determinants of health and their effects on health outcomes create a complex system, with interaction between social, economic, physical, and biological factors necessitating research take a holistic approach. Transdisciplinary research, one of the three core values of the Collaborative Research Center for American Indian Health, seeks to go beyond methods of knowledge production occurring solely within disciplinary boundaries, because real-world societal problems do not adhere to such restrictions. Community involvement is an essential component for successful research partnerships with American Indian and Alaska Native (AI/AN) communities. We posit that transdisciplinary approaches, which considers community-level expertise as an equitable component on the research team, show great potential for advancing research in AI/AN communities.

Using Social Network Analysis to Visualize Networks in American Indian Health Research.

The Collaborative Research Center for American Indian Health (CRCAIH) is a transdisciplinary, collaborative center focused on building American Indian tribal research infrastructure. Funded by the National Institute of Minority Health and Health Disparities in 2012, it was created as a platform to join tribal communities and researchers in South Dakota, North Dakota, and Minnesota to develop research infrastructure and stimulate research in American Indian health. The CRCAIH infrastructure has created a large network of transdisciplinary research partnerships. To understand the initial development of the CRCAIH network and understand the broader impact it has had on American Indian and Alaska Native health research, CRCAIH undertook a network analysis based on publications by collaborators working with and within CRCAIH. The network analysis showed how far the CRCAIH network went in a short period of time to create a platform for networking to build collaborations and further stimulate research with American Indian communities.