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- Aamodt, K., et al.
(författare)
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The ALICE experiment at the CERN LHC
- 2008
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 3:S08002
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Forskningsöversikt (refereegranskat)abstract
- ALICE (A Large Ion Collider Experiment) is a general-purpose, heavy-ion detector at the CERN LHC which focuses on QCD, the strong-interaction sector of the Standard Model. It is designed to address the physics of strongly interacting matter and the quark-gluon plasma at extreme values of energy density and temperature in nucleus-nucleus collisions. Besides running with Pb ions, the physics programme includes collisions with lighter ions, lower energy running and dedicated proton-nucleus runs. ALICE will also take data with proton beams at the top LHC energy to collect reference data for the heavy-ion programme and to address several QCD topics for which ALICE is complementary to the other LHC detectors. The ALICE detector has been built by a collaboration including currently over 1000 physicists and engineers from 105 Institutes in 30 countries, Its overall dimensions are 16 x 16 x 26 m(3) with a total weight of approximately 10 000 t. The experiment consists of 18 different detector systems each with its own specific technology choice and design constraints, driven both by the physics requirements and the experimental conditions expected at LHC. The most stringent design constraint is to cope with the extreme particle multiplicity anticipated in central Pb-Pb collisions. The different subsystems were optimized to provide high-momentum resolution as well as excellent Particle Identification (PID) over a broad range in momentum, up to the highest multiplicities predicted for LHC. This will allow for comprehensive studies of hadrons, electrons, muons, and photons produced in the collision of heavy nuclei. Most detector systems are scheduled to be installed and ready for data taking by mid-2008 when the LHC is scheduled to start operation, with the exception of parts of the Photon Spectrometer (PHOS), Transition Radiation Detector (TRD) and Electro Magnetic Calorimeter (EMCal). These detectors will be completed for the high-luminosity ion run expected in 2010. This paper describes in detail the detector components as installed for the first data taking in the summer of 2008.
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| 2. |
- Ghoreyshi, M., et al.
(författare)
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Aerodynamic modelling for flight dynamics analysis of conceptual aircraft designs
- 2009
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Ingår i: 27th AIAA Applied Aerodynamics Conference.
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Konferensbidrag (refereegranskat)abstract
- Physics based simulation in conceptual design is widely seen as a way of increasing the information about designs, thus helping with the avoidance of unanticipated problems as the design is refined. This paper reports on an effort to assess the use of CFD level aerodynamics for the development of tables for flight dynamics analysis at the conceptual stage. A number of aerodynamic data sources are used with sampling and data fusion to allow the efficient generation of the tables. A refined design passenger jet wind tunnel model is used as a test case, and three simplified conceptual versions of this geometry are generated. The influence of geometry approximations and modelling influences are evaluated to assess the usefulness of CFD for this application. Finally, the aerodynamic differences are assessed in terms of basic longitudinal flight dynamics analysis.
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| 3. |
- Rizzi, Arthur, et al.
(författare)
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What was learned from numerical simulations of F-16XL (CAWAPI) at flight conditions
- 2007
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Ingår i: Collection of Technical Papers - 45th AIAA Aerospace Sciences Meeting. - Reston, Virigina : American Institute of Aeronautics and Astronautics. - 1563478900 - 9781563478901 ; , s. 8385-8420
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Konferensbidrag (refereegranskat)abstract
- Ten groups participating in the CAWAPI project have contributed steady and unsteady viscous simulations of a full-scale, semi-span model of the F-16XL-I aircraft at three different categories of flight Reynolds/Mach number combinations for comparison with flight-test measurements for purposes of code validation and improved understanding of the flight physics of complex interacting vortical flows. The steady-state simulations are done with several turbulence models of different complexity with no topology information required and which overcome Boussinesq-assumption problems in vortical flows. Detached-Eddy Simulation (DES) has been used to compute the unsteady flow. Common structured and unstructured grids as well as individually-adapted unstructured grids have been used. Although discrepancies are observed in the comparisons, overall reasonable agreement is demonstrated for surface pressure distribution, local skin friction and boundary velocity profiles. The physical modeling, steady or unsteady, and the grid resolution both contribute to the discrepancies observed in the comparisons with flight data, but at this time it cannot be determined how much each part contributes to the whole. Overall it can be said that the technology readiness of CFD-simulation technology for the study of vehicle performance of e.g. the F-16XL has matured since 2001 such that it can be used today with a reasonable level of confidence in practical use.
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| 4. |
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| 5. |
- Wang, Andrew, et al.
(författare)
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Contemporary clinical profile and outcome of prosthetic valve endocarditis.
- 2007
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Ingår i: JAMA : the journal of the American Medical Association. - : American Medical Association (AMA). - 1538-3598. ; 297:12, s. 1354-61
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Tidskriftsartikel (refereegranskat)abstract
- CONTEXT: Prosthetic valve endocarditis (PVE) is associated with significant mortality and morbidity. The contemporary clinical profile and outcome of PVE are not well defined. OBJECTIVES: To describe the prevalence, clinical characteristics, and outcome of PVE, with attention to health care-associated infection, and to determine prognostic factors associated with in-hospital mortality. DESIGN, SETTING, AND PARTICIPANTS: Prospective, observational cohort study conducted at 61 medical centers in 28 countries, including 556 patients with definite PVE as defined by Duke University diagnostic criteria who were enrolled in the International Collaboration on Endocarditis-Prospective Cohort Study from June 2000 to August 2005. MAIN OUTCOME MEASURE: In-hospital mortality. RESULTS: Definite PVE was present in 556 (20.1%) of 2670 patients with infective endocarditis. Staphylococcus aureus was the most common causative organism (128 patients [23.0%]), followed by coagulase-negative staphylococci (94 patients [16.9%]). Health care-associated PVE was present in 203 (36.5%) of the overall cohort. Seventy-one percent of health care-associated PVE occurred within the first year of valve implantation, and the majority of cases were diagnosed after the early (60-day) period. Surgery was performed in 272 (48.9%) patients during the index hospitalization. In-hospital death occurred in 127 (22.8%) patients and was predicted by older age, health care-associated infection (62/203 [30.5%]; adjusted odds ratio [OR], 1.62; 95% confidence interval [CI], 1.08-2.44; P = .02), S aureus infection (44/128 [34.4%]; adjusted OR, 1.73; 95% CI, 1.01-2.95; P = .05), and complications of PVE, including heart failure (60/183 [32.8%]; adjusted OR, 2.33; 95% CI, 1.62-3.34; P<.001), stroke (34/101 [33.7%]; adjusted OR, 2.25; 95% CI, 1.25-4.03; P = .007), intracardiac abscess (47/144 [32.6%]; adjusted OR, 1.86; 95% CI, 1.10-3.15; P = .02), and persistent bacteremia (27/49 [55.1%]; adjusted OR, 4.29; 95% CI, 1.99-9.22; P<.001). CONCLUSIONS: Prosthetic valve endocarditis accounts for a high percentage of all cases of infective endocarditis in many regions of the world. Staphylococcus aureus is now the leading cause of PVE. Health care-associated infection significantly influences the clinical characteristics and outcome of PVE. Complications of PVE strongly predict in-hospital mortality, which remains high despite prompt diagnosis and the frequent use of surgical intervention.
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