18 research outputs found

    Stability enhancement and chatter suppression in continuous radial immersion milling

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    Acknowledgments The authors would like to thank the Federal Ministry of Economic Affairs and Energy (BMWi) and the AIF Projekt GmbH for funding this scientific paper as part of the research project "UltrahardMill" of the central Innovation Programme for SMEs. The authors appreciate Dr.-Ing. Michael Löser and Dipl.-Ing. Zhongyan Zhu from TU Dresden for discussing and modifying the content of the manuscript. Besides, Mr. Daniel Schmidt from Fraunhofer Institute for Machine Tools and Forming Technology (IWU) provided us with lots of generous help to carry out the experiments.Peer reviewedPostprin

    Investigation of a carbon fibrereinforced plastic grinding wheel for high-speed plunge-cut centreless grinding application

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    High-speed plunge-cut centreless grinding opens up enormous potential for the manufacturing of difficult-to-machine materials and to improve the surface quality while reducing the grinding forces. For this investigation, a new grinding wheel base body of carbon fibre-reinforced plastic (CFRP) was developed to achieve grinding wheel speeds up to 150 m/s in plunge-cut centreless grinding of hardened shafts. For evaluation of the performance characteristics, the grinding forces and the surface quality of different grinding tools were detected. These experiments were conducted using a newly developed measuring system to analyse the grinding forces in the workrest blade. The experimental results are described and discussed in this article

    Quality Monitoring Of Coupled Digital Twins For Multistep Process Chains Using Bayesian Networks

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    The digital representation of physical assets and process steps by digital twins is key to address pressuring challenges like adaptive manufacturing or customised production. Recent breakthroughs in the field of digital twins and Edge-based AI already enable digital optimization of individual process steps. However, high-value goods typically include multiple step process chains including a broad range from generative and additive processes over several steps of material removal up to assembly. Therefore, a digital twin over the holistic process chain is necessary. While even the set-up of representative twins for a single step is already challenging, a concept for monitoring of the interaction and overall quality control of holistic process chains does not exist yet. The paper introduces a machine-learning method based on probabilistic Bayesian networks to monitor the »digital twin quality« of coupled digital twins which includes several sub-instances of digital twins. The approach identifies the contribution of each instance to the overall prediction quality. Furthermore, it is possible to give a range-estimation for the prediction accuracy of the individual subinstances. It is therefore possible to identify the most influential sub-instances of digital twins as well as their individual prediction quality. With the help of this information, the quality of the digital twin can be improved by considering individual sub-instances in a targeted manner. Finally, a preview emphasises the potential benefits of the quantum computing technology when dealing with parallel computation of largescale inference models

    Allogeneic Stem Cell Transplantation Improves Survival in Patients with Acute Myeloid Leukemia Characterized by a High Allelic Ratio of Mutant FLT3-ITD

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    Allogeneic hematopoietic cell transplantation (alloHCT) as a postremission therapy in patients with FLT3-ITD-positive intermediate-risk acute myeloid leukemia (AML) remains controversial. FLT3-ITD mutations are heterogeneous with respect to allelic ratio, location, and length of the insertion, with a high mutant-to-wild type ratio consistently associated with inferior prognosis. We retrospectively analyzed the role of alloHCT in first remission in relationship to the allelic ratio and presence or absence of nucleophosmin 1 mutations (NPMI) in the Study Alliance Leukemia AML2003 trial. FLT3-ITD mutations were detected in 209 patients and concomitant NPMI mutations in 148 patients. Applying a predefined cutoff ratio of .8, AML was grouped into high- and low-ratio FLT3-ITD AML (HRFLT3-ITD and LRFLT3-ITD). Sixty-one patients (29%) were transplanted in first remission. Overall survival (OS) (HR, .3; 95% CI, .16 to .7; P = .004) and event-free survival (EFS) (HR, .4; 95% CI, .16 to .9; P = .02) were significantly increased in patients with HRFLT3-ITD AML who received alloHCT as consolidation treatment compared with patients who received consolidation chemotherapy. Patients with LRFLT3-ITD AML and wild-type NPMI who received alloHCT in first remission had increased OS (HR, .3; 95% CI, .1 to. 8; P = .02) and EFS (HR, .2; 95% CI, .1 to .8; P = .02), whereas alloHCT in first remission did not have a significant impact on OS and EFS in patients with LRFLT3-ITD AML and concomitant NPMI mutation. In conclusion, our results provide additional evidence that alloHCT in first remission improves EFS and OS in patients with HRFLT3-ITD AML and in patients with LRFLT3-ITD AML and wild-type NPM1. (C) 2016 American Society for Blood and Marrow Transplantation
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