| 1. |
- Aartsen, M. G., et al.
(författare)
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Very high-energy gamma-ray follow-up program using neutrino triggers from IceCube
- 2016
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- We describe and report the status of a neutrino-triggered program in IceCube that generates real-time alerts for gamma-ray follow-up observations by atmospheric-Cherenkov telescopes (MAGIC and VERITAS). While IceCube is capable of monitoring the whole sky continuously, high-energy gamma-ray telescopes have restricted fields of view and in general are unlikely to be observing a potential neutrino-flaring source at the time such neutrinos are recorded. The use of neutrino-triggered alerts thus aims at increasing the availability of simultaneous multi-messenger data during potential neutrino flaring activity, which can increase the discovery potential and constrain the phenomenological interpretation of the high-energy emission of selected source classes (e. g. blazars). The requirements of a fast and stable online analysis of potential neutrino signals and its operation are presented, along with first results of the program operating between 14 March 2012 and 31 December 2015.
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| 2. |
- Wagner, R., et al.
(författare)
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Design of an optimized nested-mirror neutron reflector for a NNBAR experiment
- 2023
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Ingår i: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 1051
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Tidskriftsartikel (refereegranskat)abstract
- The NNBAR experiment for the European Spallation Source will search for free neutrons converting to antineutrons with an expected sensitivity improvement of three orders of magnitude compared to the last such search. This paper describes both the simulations of a key component for the experiment, the neutron optical reflector and the expected gains in sensitivity.
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| 3. |
- Eklöf-Österberg, Carin, 1987, et al.
(författare)
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Dynamics of Hydride Ions in Metal Hydride-Reduced BaTiO3 Samples Investigated with Quasielastic Neutron Scattering
- 2019
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Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 123:4, s. 2019-2030
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Tidskriftsartikel (refereegranskat)abstract
- Perovskite-type oxyhydrides, BaTiO3-xHx, have been recently shown to exhibit hydride-ion (H-) conductivity at elevated temperatures, but the underlying mechanism of hydride-ion conduction and how it depends on temperature and oxygen vacancy concentration remains unclear. Here, we investigate, through the use of quasielastic neutron scattering techniques, the nature of the hydride-ion dynamics in three metal hydride-reduced BaTiO3 samples that are characterized by the simultaneous presence of hydride ions and oxygen vacancies. Measurements of elastic fixed window scans upon heating reveal the presence of quasielastic scattering due to hydride-ion dynamics for temperatures above ca. 200 K. Analyses of quasielastic spectra measured at low (225 and 250 K) and high (400-700 K) temperature show that the dynamics can be adequately described by established models of jump diffusion. At low temperature, <= 250 K, all of the models feature a characteristic jump distance of about 2.8 angstrom, thus of the order of the distance between neighboring oxygen atoms or oxygen vacancies of the perovskite lattice and a mean residence time between successive jumps of the order of 0.1 ns. At higher temperatures, >400 K, the jump distance increases to about 4 angstrom, thus of the order of the distance between next-nearest neighboring oxygen atoms or oxygen vacancies, with a mean residence time of the order of picoseconds. A diffusion constant D was computed from the data measured at low and high temperatures, respectively, and takes on values of about 0.4 X 10(-6) cm(-2) s(-1) at the lowest applied temperature of 225 K and between ca. 20 X 10(-6) and 100 X 10(-6) cm(-2) s(-1) at temperatures between 400 and 700 K. Activation energies E-a were derived from the measurements at high temperatures and take on values of about 0.1 eV and show a slight increase with increasing oxygen vacancy concentration.
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| 4. |
- Stäring, J., et al.
(författare)
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Fluctuations of the Shannon capacity in a Rayleigh model of wireless communication
- 2004
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Ingår i: Physica Status Solidi (B): Basic Research. - : Wiley. - 1521-3951 .- 0370-1972. ; 241:9, s. 2136-2138
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Tidskriftsartikel (refereegranskat)abstract
- We consider a Rayleigh model[Foschini and Gans, Wirel. Pers. Commun. 6, 311 (1998)] for the Shannon capacity characterising wireless information transfer in a network of antennae. In this model, the capacity C is a linear statistic of the channel matrix of the network. We use this fact to calculate the variance var[C] of the Shannon capacity. We find that the expected value 〈C〉 of the Shannon capacity is typical, that is the coefficient of variation √var[C]/〈C〉 is small.
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| 5. |
- Bernhard, Westerhof, et al.
(författare)
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HEAVY VEHICLE BRAKING USING FRICTION ESTIMATION FOR CONTROLLER OPTIMZATION
- 2018
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Konferensbidrag (refereegranskat)abstract
- A novel electronic brake system (EBS) has demonstrated a 17 percent reduction in stopping distance on a tractor semi-trailer combination during vehicle tests in low friction conditions relative to a modern EBS. Even though these results were promising, it was observed that the novel EBS required more information about the road surface to achieve optimal braking performance. In this paper, the development of an on-line friction estimation method for heavy vehicles, as well as an optimization method that can be used to adjust the slip controller settings, according to the road friction, is described. Results from both simulation and real testing of a Volvo 8x4 FMX truck showed that real-time friction estimation is feasible and increased braking performance can be achieved. Simulation results have shown a reduction in braking distance of up to 20 percent on most road surfaces, as well as a reduction in air usage in most cases.
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| 6. |
- Berglund, Anders, et al.
(författare)
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Co-creation beyond the expected : LAB environments as mean to enhance learning
- 2015
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Ingår i: Proceedings of the 43rd SEFI Annual Conference 2015 - Diversity in Engineering Education. - : European Society for Engineering Education (SEFI). - 9782873520120
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Konferensbidrag (refereegranskat)abstract
- Background: Co-creation is a term that has been used to emphasize collaborative learning in design education. Allowing students to develop both hard and soft skills has been demonstrated important to facilitate effective learning [1]. Mixing disciplines with each other is an important catalyzer to gain new insights and also grow applicability on societal challenges and innovation. This paper proposes a curricula design that matches student interdisciplinary learning, design challenges and societal benefit. With an aims to create innovation in the meeting between e.g., medicine, social sciences and engineers it is a process that involves empathy and capability to define, ideate, prototype and test. Creation allows prototypes to be made, which are by default presented and interpreted differently by people according to their understanding and frame of reference[2]. Purpose: The purpose of this study is to present the curriculum for a master level course that emphasis and support the creations performed by problem-solving interdisciplinary teams. The subsequent purpose is to position the course design in relation existing best practices that has presented similar challenges of merging the specific methods presented, e.g. Scrum and Design thinking. Design/Methodology: Observational notes and more than 100 student reflections, notes and remarks from more than 30 peer-to-peer faculty internal meetings, international workshops and faculty-student ?review screenings? sessions have been used to evaluate the pros and cons of the presented curriculum. Findings: Open lab has arisen as a new course offering targeting societal challenges and an unique opportunity for students to take part in. To allow divergent and radical thought patterns to arise design thinking and scrum are put together as key elements to support a dynamic learning environment already from start. Moreover, initial team building and checkpoints, pre-checks and cultural differences have been reported to be affected in a positive way resulting deepen student project understanding and appreciation. Conclusions: From initial course design and analysis the learning environment provides a catalyzer for learning to be appreciated and acted upon. The design of activities should build on a shared perspective from faculty and motivate students and convincing them to deepen their need for interdisciplinary design. By working interdisciplinary and collaborative it has been possible for students to co-create new knowledge beyond the expected from the stakeholders? perspective.
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| 7. |
- Candelier, F., et al.
(författare)
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Role of inertia for the rotation of a nearly spherical particle in a general linear flow
- 2015
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Ingår i: Physical Review E. Statistical, Nonlinear, and Soft Matter Physics. - 1539-3755 .- 1550-2376. ; 91:5
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Tidskriftsartikel (refereegranskat)abstract
- We analyze the angular dynamics of a neutrally buoyant, nearly spherical particle immersed in a steady general linear flow. The hydrodynamic torque acting on the particle is obtained by means of a reciprocal theorem, a regular perturbation theory exploiting the small eccentricity of the nearly spherical particle, and by assuming that inertial effects are small but finite.
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| 8. |
- Caroff, Philippe, et al.
(författare)
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InAs film grown on Si(111) by Metalorganic Vapor Phase Epitaxy
- 2008
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Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 100, s. 042017-042017
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Konferensbidrag (refereegranskat)abstract
- We report the successful growth of high quality InAs films directly on Si( 111) by Metal Organic Vapor Phase Epitaxy. A nearly mirror-like and uniform InAs film is obtained at 580 C for a thickness of 2 mu m. We measured a high value of the electron mobility of 5100 cm(2)/Vs at room temperature. The growth is performed using a standard two-step procedure. The influence of the nucleation layer, group V flow rate, and layer thickness on the electrical and morphological properties of the InAs film have been investigated. We present results of our studies by Atomic Force Microscopy, Scanning Electron Microscopy, electrical Hall/van der Pauw and structural X-Ray Diffraction characterization.
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| 9. |
- Herrgård, Markus J, et al.
(författare)
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A consensus yeast metabolic network reconstruction obtained from a community approach to systems biology
- 2008
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Ingår i: Nature Biotechnology. ; 26:10, s. 1155-1160
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Tidskriftsartikel (refereegranskat)abstract
- Genomic data allow the large-scale manual or semi-automated assembly of metabolic network reconstructions, which provide highly curated organism-specific knowledge bases. Although several genome-scale network reconstructions describe Saccharomyces cerevisiae metabolism, they differ in scope and content, and use different terminologies to describe the same chemical entities. This make comparisons between them difficult and underscores the desirability of a consolidated metabolic network that collects and formalizes the 'community knowledge' of yeast metabolism. We describe how we have produced a consensus metabolic network reconstruction for S. cerevisiae. In drafting it, we placed special emphasis on referencing molecules to persistent databases or using database-independent forms, such as SMILES or InChl strings, as this permits their chemical structure to be represented unambiguously and in a manner that permits automated reasoning. The reconstruction is readily available via a publicly accessible database and in the Systems Biology Markup Language (http://www.comp-sys-bio.org/yeastnet). It can be maintained as a resource that serves as a common denominator for studying the systems biology of yeast. Similar strategies should benefit communities studying genome-scale metabolic networks of other organisms.
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| 10. |
- Holttinen, Hannele, et al.
(författare)
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Impacts of large amounts of wind power on design and operation of power systems, results of IEA collaboration
- 2011
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Ingår i: Wind Energy. - : Wiley. - 1095-4244 .- 1099-1824. ; 14:2, s. 179-192
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Tidskriftsartikel (refereegranskat)abstract
- There are dozens of studies made and ongoing related to wind integration. However, the results are not easy to compare. IEA WIND R&D Task 25 on 'Design and Operation of Power Systems with Large Amounts of Wind Power' collects and shares information on wind generation impacts on power systems, with analyses and guidelines on methodologies. In the state-of-the-art report (October, 2007), and the final report of the 3 years period (July, 2009) the most relevant wind power grid integration studies have been analysed especially regarding methodologies and input data. Several issues that impact on the amount of wind power that can be integrated have been identified. Large balancing areas and aggregation benefits of wide areas help in reducing the variability and forecast errors of wind power as well as help in pooling more cost effective balancing resources. System operation and functioning electricity markets at less than day-ahead time scales help reduce forecast errors of wind power. Transmission is the key to aggregation benefits, electricity markets and larger balancing areas. Best practices in wind integration studies are described. There is also benefit when adding wind power to power systems: it reduces the total operating costs and emissions as wind replaces fossil fuels and this should be highlighted more in future studies.
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