| 1. |
- Abelev, Betty, et al.
(författare)
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Underlying Event measurements in pp collisions at root s=0.9 and 7 TeV with the ALICE experiment at the LHC
- 2012
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Ingår i: Journal of High Energy Physics. - 1029-8479. ; :7
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Tidskriftsartikel (refereegranskat)abstract
- We present measurements of Underlying Event observables in pp collisions at root s = 0 : 9 and 7 TeV. The analysis is performed as a function of the highest charged-particle transverse momentum p(T),L-T in the event. Different regions are defined with respect to the azimuthal direction of the leading (highest transverse momentum) track: Toward, Transverse and Away. The Toward and Away regions collect the fragmentation products of the hardest partonic interaction. The Transverse region is expected to be most sensitive to the Underlying Event activity. The study is performed with charged particles above three different p(T) thresholds: 0.15, 0.5 and 1.0 GeV/c. In the Transverse region we observe an increase in the multiplicity of a factor 2-3 between the lower and higher collision energies, depending on the track p(T) threshold considered. Data are compared to PYTHIA 6.4, PYTHIA 8.1 and PHOJET. On average, all models considered underestimate the multiplicity and summed p(T) in the Transverse region by about 10-30%.
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| 2. |
- Abelev, Betty, et al.
(författare)
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Measurement of prompt J/psi and beauty hadron production cross sections at mid-rapidity in pp collisions at root s=7 TeV
- 2012
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Ingår i: Journal of High Energy Physics. - 1029-8479. ; :11
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Tidskriftsartikel (refereegranskat)abstract
- The ALICE experiment at the LHC has studied J/psi production at mid-rapidity in pp collisions at root s = 7 TeV through its electron pair decay on a data sample corresponding to an integrated luminosity L-int = 5.6 nb(-1). The fraction of J/psi from the decay of long-lived beauty hadrons was determined for J/psi candidates with transverse momentum p(t) > 1,3 GeV/c and rapidity vertical bar y vertical bar < 0.9. The cross section for prompt J/psi mesons, i.e. directly produced J/psi and prompt decays of heavier charmonium states such as the psi(2S) and chi(c) resonances, is sigma(prompt J/psi) (p(t) > 1.3 GeV/c, vertical bar y vertical bar < 0.9) = 8.3 +/- 0.8(stat.) +/- 1.1 (syst.)(-1.4)(+1.5) (syst. pol.) mu b. The cross section for the production of b-hadrons decaying to J/psi with p(t) > 1.3 GeV/c and vertical bar y vertical bar < 0.9 is a sigma(J/psi <- hB) (p(t) > 1.3 GeV/c, vertical bar y vertical bar < 0.9) = 1.46 +/- 0.38 (stat.)(-0.32)(+0.26) (syst.) mu b. The results are compared to QCD model predictions. The shape of the p(t) and y distributions of b-quarks predicted by perturbative QCD model calculations are used to extrapolate the measured cross section to derive the b (b) over bar pair total cross section and d sigma/dy at mid-rapidity.
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| 3. |
- Aad, G., et al.
(författare)
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- 2014
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Ingår i: Physical Review D (Particles, Fields, Gravitation and Cosmology). - 1550-2368 .- 1550-7998. ; 90:11
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Tidskriftsartikel (refereegranskat)
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| 4. |
- Dalda, Alberto Sainz, et al.
(författare)
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Recovering Thermodynamics from Spectral Profiles observed by IRIS : A Machine and Deep Learning Approach
- 2019
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Ingår i: Astrophysical Journal Letters. - : American Astronomical Society. - 2041-8205 .- 2041-8213. ; 875:2
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Tidskriftsartikel (refereegranskat)abstract
- Inversion codes allow the reconstruction of a model atmosphere from observations. With the inclusion of optically thick lines that form in the solar chromosphere, such modeling is computationally very expensive because a non-LTE evaluation of the radiation field is required. In this study, we combine the results provided by these traditional methods with machine and deep learning techniques to obtain similar-quality results in an easy-to-use, much faster way. We have applied these new methods to Mg II h and k lines observed by the Interface Region Imaging Spectrograph (IRIS). As a result, we are able to reconstruct the thermodynamic state (temperature, line-of-sight velocity, nonthermal velocities, electron density, etc.) in the chromosphere and upper photosphere of an area equivalent to an active region in a few CPU minutes, speeding up the process by a factor of 10(5) - 10(6). The opensource code accompanying this Letter will allow the community to use IRIS observations to open a new window to a host of solar phenomena.
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| 5. |
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| 6. |
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| 7. |
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| 8. |
- Clausen, Tommy, et al.
(författare)
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Mobilizing for change : A study of research units in emerging scientific fields
- 2018
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Ingår i: Innovation, Economic Development and Policy : Selected Essays - Selected Essays. - : Edward Elgar Publishing. - 9781788110259 - 9781788110266 ; , s. 147-159
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Bokkapitel (refereegranskat)abstract
- Local research units, this article argues, play a very important role for the scientific field they belong to, for example by mobilizing financial support, offering job opportunities, attracting talented recruits, and providing adequate training. Little is known, however, about such units, at least in the fields under study here, i.e., studies of innovation, entrepreneurship and related phenomena. This article focuses-with the help of a survey of 136 research units worldwide supplemented by a number of case-studies-on the factors that influence the extent to which local mobilization efforts succeed. The research shows that universities provide the most fertile grounds for such research units, and that external support and support from the leadership of the university are important factors behind their establishment. In the longer term, however, attracting core (basic) finance is essential for the unit's ability to maintain cognitive control of its research program. Units that develop their own Master and PhD programs appear more likely than others to achieve these aims.
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| 9. |
- Enger, Johanna, 1970-
(författare)
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In search for the language of light and shadows
- 2023
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Konferensbidrag (populärvet., debatt m.m.)abstract
- Sight is the sense that gives us visual information about the world around us, and light is a prerequisite for this process. Light radiation can be measured physically with precision, but light as the experience created when light rays strike the retina of the eye is sensual, and thus both subjective, relative and complex. Like all impressions that reach our different senses, the visual experience of the outside world is created through processes that can be described from the basis of sensory, biology, physiology, perception, cognition and emotion. These processes cannot be translated into physical terms. We can measure stimuli that reaches the retina, but this gives very limited information about the experience.In the beginning, when all life existed in the sea, some organisms developed cells that were sensitive to light, allowing them to orient themselves to brighter or darker areas. This early capacity for visual information produced blurred visual impressions, only detecting differences between contrasts. Eventually, more advanced life forms developed the sharp central vision which, according to one hypothesis, appeared during a period when life had evolved into a predator prey interaction. Both these visual abilities, the blurred peripheral vision and the detailed focus vision are represented in the human sense of sight, and the blurred peripheral vision is crucial for our visual experience of the room.All the light we see is reflected from surfaces, unless you look directly into a light source. The properties of surfaces, their colour and texture in combination with the properties of the light source and the distribution of the light is what provides visual information about the room. It is through the modelling and interaction of light and colours that the experience of the room can appear with its shapes and textures, proportions, dimensions, depth and spatiality.Since electric light was introduced in our built environments about 100 years ago, light quality has been evaluated and regulated based on physical measurements, which are correlated to the human eye’s ability to register light and colour. International lighting standards for spatial environments provide detailed recommendations for light levels described in Lux or Footcandle. These measurements are based on the focus vision, which require higher light levels to function optimally. But the measurements do not provide information about the properties of the reflected light, which is what we see, nor does it include one of the basic functions of the sense of sight, which is to react and respond to contrasts.The beverage and food industries have for many years used terminologies and concept models that describe sensory properties of various products. The underlying methodology is called Sensory Analysis which is established in several different areas. Within the interdisciplinary research project Perceptual Metrics for Lighting Design, we have developed methods to measure perceived light quality for both light sources, luminaires and spatial environments with inspiration from Sensory Analysis. The project has been developed with a practice based and design-oriented approach,in close collaboration with the lighting industry. On workshops with lighting designers, we have collected words that describe the perceived character of light, shadows and contrast, and through repeated studies been able to develop the basis for a terminology to give value or measure perceived light quality in spatial contexts. An interesting and important aspect that has become apparent during the course of this project is how much light, shadows and contrasts affects the atmosphere of environments.The lecture will give an overview of the human visual perception in relation to how we perceive spatial environments, and also a description of the Perceptual Metrics for Lighting Design method and how it may be used in practice and research.
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| 10. |
- Estenlund, Samuel, et al.
(författare)
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Dovetail Design for Direct Cooled Rotor: Design and Manufacturing
- 2022
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Ingår i: 2022 International Conference on Electrical Machines (ICEM). - 9781665414326 ; , s. 2121-2127
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Konferensbidrag (refereegranskat)abstract
- This work investigates dovetail joints as a means to mount pre-wound coils in an electrically excited rotor for a synchronous machine for EV application. The aim is to manufacture a prototype of a direct cooled machine with hollow rectangular rotor windings which requires a rotor design where the windings can be applied on the poles separately. Two experimental tensile tests are made to validate the mechanical simulation data, which are combined with electromagnetic simulations to optimize a dovetail design for assembly, mechanical strength and electromagnetic performance. The prototype is manufactured and assembled and preliminary tests are performed.
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