Runtime-guided mitigation of manufacturing variability in power-constrained multi-socket NUMA nodes

This work has been supported by the Spanish Government (Severo Ochoa grants SEV2015-0493, SEV-2011-00067), by the Spanish Ministry of Science and Innovation (contracts TIN2015-65316-P), by Generalitat de Catalunya (contracts 2014-SGR-1051 and 2014-SGR-1272), by the RoMoL ERC Advanced Grant (GA 321253) and the European HiPEAC Network of Excellence. M. Moretó has been partially supported by the Ministry of Economy and Competitiveness under Juan de la Cierva postdoctoral fellowship number JCI-2012-15047. M. Casas is supported by the Secretary for Universities and Research of the Ministry of Economy and Knowledge of the Government of Catalonia and the Cofund programme of the Marie Curie Actions of the 7th R&D Framework Programme of the European Union (Contract 2013 BP B 00243). This work was also partially performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 (LLNL-CONF-689878). Finally, the authors are grateful to the reviewers for their valuable comments, to the RoMoL team, to Xavier Teruel and Kallia Chronaki from the Programming Models group of BSC and the Computation Department of LLNL for their technical support and useful feedback.Peer ReviewedPostprint (published version

Microstructure and mechanical properties of Haynes 282 superalloy produced by laser powder bed fusion

Ni-base superalloys are essential materials for high-temperature applications in the energy and aerospace sectors. Significant benefits in design, function, and manufacture of high-temperature components may be realized from additive manufacturing (AM) of these materials. However, because of cracking issues during AM fabrication, only a handful of materials have been tried and qualified. This article provides an initial evaluation of theprocessability and properties of Haynes 282 by laser-powder bed fusion (LPBF), which is a relatively new Ni-base superalloy with properties superior to those of many legacy wrought superalloys. The results demonstrated that crack-free Haynes 282 can be manufactured by means of LPBF with full density. The mechanical properties at ambient temperature exceeded the properties of the reference material in the as-built and heat-treated conditions, albeit with significant anisotropy. Mechanical properties at 800 ◦C indicated that the yield strength of heattreated Haynes 282 by LPBF was comparable to that of the reference material, however, ductility was significantly reduced. Promising stress rupture performance also indicates that Haynes 282 is an ideal candidate for adoption in additive manufacturing, especially if heat treatments can be re-designed for the additively manufactured as-built microstructure

On the role of Zr and B addition on solidification cracking of IN738LC produced by laser powder bed fusion

The demand for manufacturing increasingly complex geometries for high temperature applications drives the increasing interest into additive manufacturing of nickel-based superalloys. Of particular interest are superalloys with high contents of the strengthening phase γ\u27 such as IN738LC. Previous research suggests that especially B and Zr have a detrimental influence on crack formation during the laser powder bed fusion (LPBF) process. The present study investigates solidification cracks in an IN738LC derivative with increased B (0.03 wt.%) and Zr (0.07 wt.%) in more detail using high resolution techniques such as transmission electron microscopy (TEM) and atom probe tomography (APT). Analysis of the bulk material shows a high number of MC carbides containing Ti and Cr. The concentration profiles indicate non-equilibrium carbide compositions by suggesting that Cr is pushed out of these particles. The carbides are surrounded by a thin B-rich layer at the metal/carbide interface. Analysis of the fracture surface shows both Zr and small amounts of B in the formed oxide layer. The presence of these elements together with thermodynamic calculations and previously reported findings of the same material variant support the hypothesis that low-melting phases are likely reasons for cracking of IN738LC

The role of microstructural characteristics of additively manufactured Alloy 718 on tool wear in machining

This study aims to provide a fundamental understanding of the role of microstructural characteristics influencing tool wear when machining Alloy 718 fabricated using Powder Bed Fusion (PBF). The effects of preferred crystallographic orientation (texture), shape and distribution of grains, local misorientation, type and amount of precipitates as well as the type, size and amount of abrasive carbides, nitrides and oxides on tool wear are investigated in as-built condition and after the standard solutionising and double-aging treatment. The microstructures of workpiece materials and the surfaces of worn tools were examined using different material characterisation techniques, including Scanning Electron Microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and electron backscatter diffraction (EBSD). A dislocation-based approach was used to reveal the cumulative effects of the microstructural characteristics on deformation behaviour and the thermo-mechanical loads on the tools during cutting. The analyses suggest that texture and the extent of material work-hardening prior to the onset of crack formation markedly influence the amount of plastic work and thus heat generation when machining Electron Beam Powder Bed Fusion (EB-PBF) material. The higher heat generation in the cutting zones provokes thermally-induced wear mechanisms like diffusion-dissolution and oxidation. In addition, the larger amount of hard oxide inclusions present in EB-PBF material leads to higher wear by abrasion. In contrast to the prevailing experimental approaches in this field, the present investigation is built on a physics-based framework to understand the fundamental aspects that govern material deformation and heat generation in cutting and, consequently, tool wear mechanisms. This framework can be used for machinability assessment of any alloy manufactured by different additive manufacturing (AM) technologies and for optimising the process-chain, including printing strategies and thermal post-treatments, to improve the machinability of AM alloys by tailoring their microstructure

Towards resilient EU HPC systems: A blueprint

This document aims to spearhead a Europe-wide discussion on HPC system resilience and to help the European HPC community define best practices for resilience. We analyse a wide range of state-of-the-art resilience mechanisms and recommend the most effective approaches to employ in large-scale HPC systems. Our guidelines will be useful in the allocation of available resources, as well as guiding researchers and research funding towards the enhancement of resilience approaches with the highest priority and utility. Although our work is focused on the needs of next generation HPC systems in Europe, the principles and evaluations are applicable globally.This work has received funding from the European Union’s Horizon 2020 research and innovation programme under the projects ECOSCALE (grant agreement No 671632), EPI (grant agreement No 826647), EuroEXA (grant agreement No 754337), Eurolab4HPC (grant agreement No 800962), EVOLVE (grant agreement No 825061), EXA2PRO (grant agreement No 801015), ExaNest (grant agreement No 671553), ExaNoDe (grant agreement No 671578), EXDCI-2 (grant agreement No 800957), LEGaTO (grant agreement No 780681), MB2020 (grant agreement No 779877), RECIPE (grant agreement No 801137) and SDK4ED (grant agreement No 780572). The work was also supported by the European Commission’s Seventh Framework Programme under the projects CLERECO (grant agreement No 611404), the NCSA-Inria-ANL-BSC-JSCRiken-UTK Joint-Laboratory for Extreme Scale Computing – JLESC (https://jlesc.github.io/), OMPI-X project (No ECP-2.3.1.17) and the Spanish Government through Severo Ochoa programme (SEV-2015-0493). This work was sponsored in part by the U.S. Department of Energy's Office of Advanced Scientific Computing Research, program managers Robinson Pino and Lucy Nowell. This manuscript has been authored by UT-Battelle, LLC under Contract No DE-AC05-00OR22725 with the U.S. Department of Energy.Preprin

Germline mutations in the DNA damage response genes BRCA1, BRCA2, BARD1 and TP53 in patients with therapy related myeloid neoplasms

Therapy related myeloid neoplasms (t-MNs) are complex diseases originating from an interplay between exogenous toxicities and a susceptible organism. It has been hypothesised that in a subset of cases t-MNs develop in the context of hereditary cancer predisposition syndromes

Assessment of socio-techno-economic factors affecting the market adoption and evolution of 5G networks: Evidence from the 5G-PPP CHARISMA project

5G networks are rapidly becoming the means to accommodate the complex demands of vertical sectors. The European project CHARISMA is aiming to develop a hierarchical, distributed-intelligence 5G architecture, offering low latency, security, and open access as features intrinsic to its design. Finding its place in such a complex landscape consisting of heterogeneous technologies and devices, requires the designers of the CHARISMA and other similar 5G architectures, as well as other related market actors to take into account the multiple technical, economic and social aspects that will affect the deployment and the rate of adoption of 5G networks by the general public. In this paper, a roadmapping activity identifying the key technological and socio-economic issues is performed, so as to help ensure a smooth transition from the legacy to future 5G networks. Based on the fuzzy Analytical Hierarchy Process (AHP) method, a survey of pairwise comparisons has been conducted within the CHARISMA project by 5G technology and deployment experts, with several critical aspects identified and prioritized. The conclusions drawn are expected to be a valuable tool for decision and policy makers as well as for stakeholders