7,740 research outputs found
Data-driven Design of Engineering Processes with COREPROModeler
Enterprises increasingly demand IT support for the coordination of their engineering processes, which often consist of hundreds up to thousands of sub-processes. From a technical viewpoint, these sub-processes have to be concurrently executed and synchronized considering numerous interdependencies.
So far, this coordination has mainly been accomplished manually, which has resulted in errors and inconsistencies. In order to deal with this problem, we have to better understand the interdependencies between the subprocesses to be coordinated. In particular, we can benefit from the fact that sub-processes are often correlated to the assembly of a product (represented by a product data structure). This information can be utilized for the modeling and execution of so-called data-driven process structures. In this paper, we present the COREPRO demonstrator that supports the data-driven modeling of these process structures. The approach explicitly establishes a close linkage between product data structures and engineering processes
Observation of electron spin resonance of negative ions in liquid helium
Electron spin resonance signals of negative ions in liquid helium were observed. The line width and g-value were measured. Electrons injected into helium by field emission from ferromagnetic tips are shown to be polarized. A new technique for the measurement of electron spin polarization is presented
Young adults’ conceptions of ‘good’ citizenship behaviours: a latent class analysis
Democracies need an active civic society, and early adulthood is a significant period in life for becoming an engaged citizen. The research reported on here categorized young Australians according to their conceptions of good citizenship using latent class analysis. Half of the sample were characterized as either ‘engaged’ or ‘duty-based,’ suggesting that there is more to consider when talking about citizenship norms and value changes, as the other half comprised ‘enthusiastic’ and ‘subject’ citizens. Prior participation was almost unrelated to those citizenship norms. The findings provide implications for an active citizenry, and the discussion addresses limitations and directions for future research
Phenomenology of the minimal supersymmetric extension of the standard model
We discuss the minimal supersymmetric extension of
the standard model. Gauge couplings unify as in the MSSM, even if the scale of
breaking is as low as order TeV and the model can be
embedded into an SO(10) grand unified theory. The phenomenology of the model
differs in some important aspects from the MSSM, leading potentially to rich
phenomenology at the LHC. It predicts more light Higgs states and the mostly
left CP-even Higgs has a mass reaching easily 125 GeV, with no constraints on
the SUSY spectrum. Right sneutrinos can be the lightest supersymmetric
particle, changing all dark matter constraints on SUSY parameter space. The
model has seven neutralinos and squark/gluino decay chains involve more
complicated cascades than in the MSSM. We also discuss briefly low-energy and
accelerator constraints on the model, where the most important limits come from
recent searches at the LHC and upper limits on lepton flavour violation.Comment: 46 pages, 11 figure
Civic Participation of High School Students: The Effect of Civic Learning in School
Building active and informed citizens is a major part of civics and citizenship education in order to enhance and sustain democracies. Civic learning and civic action opportunities within school contexts are commonly claimed to promote an active and informed citizenry. In the present research, we examine the meaning of formal civics education and the role of students’ participation in a range of curricular and extracurricular activities. Multilevel analyses yield quite stable results across two cohorts of Australian secondary students and reveal that schools account for a surprisingly small share in students’ willingness to participate in future civic and political action. Among the influences at the student level, formal civics learning, participation in student governance activities and in the community are the most significant predictors of intended future participation, but some effects vary conditional on whether more conventional or issue-related civic participation is the focus of active citizenship. Implications of these findings for democratic policy and practice are discussed
3D CFD Arc Fault Simulation in Gas-Insulated Switchgears
Arc fault processes can lead to strong damages in gas-insulated switchgears and have to be considered in the development process. In order to reduce test costs, the development of overpressure protection systems can be supported by CFD arc fault simulations. The paper deals with the modelling and simulation of arc fault processes in gas--insulated switchgears. The developed simulation tool takes into account a three-dimensional arc model and the opening of a rupture disc during the arc fault process. The influence of different insulating media as e.g. SF6, Air and CO2 on the arc fault process has been investigated. The simulation model has been validated by measured signals for pressure build-up and arc voltage
Exploring deep microbial life in coal-bearing sediment down to ~2.5 km below the ocean floor
Microbial life inhabits deeply buried marine sediments, but the extent of this vast ecosystem remains poorly constrained. Here we provide evidence for the existence of microbial communities in ~40° to 60°C sediment associated with lignite coal beds at ~1.5 to 2.5 km below the seafloor in the Pacific Ocean off Japan. Microbial methanogenesis was indicated by the isotopic compositions of methane and carbon dioxide, biomarkers, cultivation data, and gas compositions. Concentrations of indigenous microbial cells below 1.5 km ranged from <10 to ~10^4 cells cm^(−3). Peak concentrations occurred in lignite layers, where communities differed markedly from shallower subseafloor communities and instead resembled organotrophic communities in forest soils. This suggests that terrigenous sediments retain indigenous community members tens of millions of years after burial in the seabed
Reflector antennas with low sidelobes, low cross polarization, and high aperture efficiency
Techniques are presented for computing the horn near field patterns on the subreflectors and for correcting the phase center errors of the horn pattern by shaping the subreflector surface. The diffraction pattern computations for scanned beams are described. The effects of dish aperture diffraction on pattern bandwidth are investigated. A model antenna consisting of a reflector, shaped subreflector, and corrugated feed horn is described
CFD Arc Simulation of a Switching-off Process in a Model Chamber
This paper deals with the investigation of the switching arc process in a model chamber by CFD arc simulation. A transient axisymmetric model based on the @Fluent software is used. The applied arc model considers electromagnetic phenomena, radiative transfer, ablation of PTFE parts and pin motion as well. The influence of the boundary conditions for the solution of the current continuity equation is highlighted. The obtained results are validated by measurements on the model chamber [1]
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