Adaptive smoothing techniques for 3-D unstructured meshes

To correctly capture the behavior of deforming material volumes in 3-D, the Los Alamos unstructured grid code X3D has access to a variety of moving mesh algorithms. The authors present two such algorithms which markedly differ in their computational complexity. The first algorithm, Moving finite Elements for Surfaces, has only 2-D computational complexity, in that they only solve for interface motions and obtain volume point motions through interpolation. The second algorithm, Minimum Error Gradient Adaption, has 3-D complexity, since the volume tetrahedral deformations must be computed. Naturally, the 3-D complexity algorithm can model realistically a larger class of physical problems than the lower complexity approach. They present examples in metallic grain growth and semiconductor process modeling

Model-based Analysis of Reassembly Processes within the Regeneration of Complex Capital Goods

In regenerating complex capital goods two of the key criteria for success on the market include keeping downtimes to a minimum in order to realize short throughput times and maintaining a high degree of schedule reliability. When unable to comply with the market's demands on their logistical performance, companies that provide regeneration services are faced with significant financial penalties and costs for delays as well as the threat of customers switching to competitors. In addition, regeneration processes must be economically effective. Efficiently designing and planning the entire regeneration process is therefore indispensable. As a core element, the reassembly at the end of the process chain plays a key role. Since the various material flows merge together here, the logistic quality of the supply processes is particularly visible at this point. Furthermore, reassembly is generally the last value-adding process within the regeneration supply chain. Up until now, descriptive and analytical approaches consider the various supply processes independently of one another and ignore to some degree existing statistical dependencies between these processes. These dependencies however, are frequently found in the industry and have to be taken into consideration when planning tasks and evaluating design measures. This paper will thus introduce the different existing approaches for describing and analyzing reassembly processes and compare them using a case study

Evaluating the Logistic Performance Capability of Regeneration Processes

For years now, it has been recognized that logistic performance capability contributes enormously to a production enterprise's competitiveness and as such is a critical control lever. In doing so, the orientation on customer wishes (e.g. delivery dates) represents a key parameter not only in the value-adding production but also in product regeneration. Since production and regeneration processes have different characteristics, production planning and control measures cannot be directly transferred to regeneration processes. As part of a special research project, the Institute of Production Systems and Logistics Hannover is focused on increasing the logistic performance capability of regeneration processes for complex capital goods. The aim is to ensure logistic targets are met by implementing a model specifically designed to align the capacities and load in regeneration processes

Glucose, acetate and succinate metabolism in thehalophilic archaeon Haloferax volcanii: Identification and characterization of enzymesand analyses of deletion mutants

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Modular Smart Transformer Topology for the Interconnection of Multiple Isolated AC and DC Grids

The Smart Transformer enables the interconnection of multiple AC and DC grids with potentially different voltage levels. In most configurations, each grid needs to be isolated for preventing the propagation of faults. Actual literature mostly considers a single isolated interconnection, which is not opti-mized for the interconnection of multiple AC and DC grids. By utilizing the modularity of the Cascaded H-Bridge (CHB) converter and the corresponding connected Dual Active Bridge (DAB) to each H-bridge, this work proposes a system design for feeding multiple AC and DC grids. Requirements for the DC grid isolation and integration are discussed and the proposed topology is demonstrated to enable reduced losses compared to the commonly adopted configuration. The commonly adopted and the proposed configuration are compared and experimental results validate reduced losses for a large range of operation compared to the conventional solution

Optical Sensing Applied to Thermal Observers for Enhanced Reliability of Power Modules

Condition Monitoring using thermal variables has been identified as one of the most critical aspects when assessing the performance and degradation of Power Modules (PMs). Different sensing technologies and algorithms have been proposed in order to develop high-performance reliability-driven control of PMs. This paper focuses on the application of contact-based fiber optic temperature sensors in thermal observers. These sensors have the potential to become key enhancers of real-time thermal monitoring applications. One specific power systems application is evaluated by assessing the dynamic capacity of converters under contingency operation via digital twins. The assessment of the dynamic capacity is limited to the most critical element, which normally corresponds to power electronics due to their small time constant. The application of these sensors extends the safety range of operation based on real-time operational data, rather than based on design

3D modeling of metallic grain growth

This paper will describe simulating metallic grain growth using the Gradient Weighted Moving Finite Elements code, GRAIN3D. The authors also describe the set of mesh topology change operations developed to respond to changes in the physical topology such as the collapse of grains and to maintain uniform calculational mesh quality. Validation of the method is demonstrated by comparison to analytic calculations. The authors present results of multigrain simulations where grain boundaries evolve by mean curvature motion and include results which incorporate grain boundary orientation dependence

An optimal finite element mesh for elastostatic structural analysis problems

This paper investigates the adaptive solution of a class of elastic structural analysis problems through re-positioning of the finite element nodal points (r-refinement) using an approach known as the moving finite element method. Initially this adaptive method is derived for the elasticity problems of interest and it is then proved that, under certain conditions, the algorithm can yield optimal piecewise linear solutions on optimal simplicial finite element meshes. The equations of linear elasticity are then used to illustrate both the method itself and the optimality result that is derived. Finally, a number of numerical calculations are made to provide verification of the theoretical results