| 51. |
- Barabash, Victoria
(författare)
-
Are variations in PMSE intensity affected by energetic particle precipitation?
- 2002
-
Ingår i: Annales Geophysicae. - : Copernicus GmbH. - 0992-7689 .- 1432-0576. ; 20, s. 539-545
-
Tidskriftsartikel (refereegranskat)abstract
- Abstract. The correlation between variations in Polar Mesosphere Summer Echoes (PMSE) and variations in energetic particle precipitation is examined. PMSE were observed by the Esrange VHF MST Radar (ESRAD) at 67°53' N, 21°06' E. The 30 MHz riometer in Abisko (68°24' N, 18°54' E) registered radio wave absorption caused by ionization changes in response to energetic particle precipitation. The relationship between the linear PMSE intensity and the square of absorption has been estimated using the Pearson linear correlation and the Spearman rank correlation. The mean diurnal variation of the square of absorption and the linear PMSE intensity are highly correlated. However, their day-to-day variations show significant correlation only during the late evening hours. The correlation in late evening does not exceed 0.6. This indicates that varying ionization cannot be considered as a primary source of varying PMSE, and the high correlation found when mean diurnal variations are compared is likely a by-product of daily variations caused by other factors.Key words. Ionosphere (particle precipitation) Magnetospheric physics (energetic particles, precipitating) Meteorology and atmospheric dynamics (precipitation)
|
|
| 52. |
- Barnes, David L., et al.
(författare)
-
Operation of soil vapor extraction in cold climates
- 2002
-
Ingår i: Cold regions engineering. - New York : American Society of Civil Engineers (ASCE). - 784406219 ; , s. 956-967
-
Konferensbidrag (refereegranskat)abstract
- Soil Vapor Extraction has proven to be a viable method for reducing the mass of volatile compounds from soils that have been impacted by contamination. The theory, design and use of SVE systems have been fairly well documented, however the use of SVE systems in cold environments such as Alaska has not been adequately investigated to date. This paper examines the use of SVE systems in cold environments. The affect of low soil temperatures on volatile compound removal by SVE is discussed. Methods used to overcome the impact low temperatures have on the operation and effectiveness of SVE systems are examined in detail. Possible low cost strategies such as barometric pumping during winter months are presented as solutions to reducing SVE operating costs in cold regions
|
|
| 53. |
- Barry, Jim, et al.
(författare)
-
Clinical Psychologists and Kwik-Therapy
- 2002
-
Ingår i: 20th anniversary Standing Conference on Organisational Symbolism. - Pontypridd : Business School, University of Glamorgan. - 1840540621
-
Konferensbidrag (refereegranskat)
|
|
| 54. |
|
|
| 55. |
|
|
| 56. |
- Barza, Sorina, et al.
(författare)
-
Duality theorem over the cone of monotone functions and sequences in higher dimensions
- 2002
-
Ingår i: Journal of inequalities and applications. - 1025-5834 .- 1029-242X. ; 7:1, s. 79-108
-
Tidskriftsartikel (refereegranskat)abstract
- Let f be a non-negative function defined on ℝ+n which is monotone in each variable separately. If 1 < p < ∞, g ≥ 0 and v a product weight function, then equivalent expressions for sup ∫ℝ(+)(n) fg/(ℝ+nfpv)1/p are given, where the supremum is taken over all such functions f. Variants of such duality results involving sequences are also given. Applications involving weight characterizations for which operators defined on such functions (sequences) are bounded in weighted Lebesgue (sequence) spaces are also pointed out.
|
|
| 57. |
|
|
| 58. |
- Bengtsson, Peter, et al.
(författare)
-
Significance of the dimensional view for visualizing relevant aspects of a production system in a co-operative planning process
- 2002
-
Ingår i: Ergonomics. - : Informa UK Limited. - 0014-0139 .- 1366-5847. ; 45:13, s. 910-921
-
Tidskriftsartikel (refereegranskat)abstract
- Pictorial visualization is expected to facilitate communication between industrial professionals when planning working environments and production systems. This hypothesis was investigated by studying how 24 participants including managers, supervisors, machine operators, and occupational health and safety officials, judged three types of computer animated visualization varying in dimensional view (scale and scope of a production line):shop floor view/survey of shop floor; production unit view/semi-survey of production unit; and workplace view/close-up of workplace, in relation to a set of planning issues. The participants participated in a controlled 2-day planning workshop, redesigning a fictitious manufacturing process by means of computer graphics, and then responded to a questionnaire. It can be concluded that shop floor view as well as production unit view are significant for survey planning issues, while all 3-dimensional views are significant for close-up planning issues. Analogously, all dimensional views are significant for technocentric planning issues, whereas only the workplace view is valuable for anthropocentric planning issues.
|
|
| 59. |
- Benini, Ernesto, et al.
(författare)
-
Axial-flow compressor model based on a cascade stacking technique and neural networks
- 2002
-
Ingår i: Proceedings of the ASME Turbo Expo 2002 Turbomachinery. - New York : American Society of Mechanical Engineers. - 079183610X ; , s. 793-801
-
Konferensbidrag (refereegranskat)abstract
- This paper introduces a cascade-stacking technique for the development of a gas turbine multi-stage axial-flow compressor model. A large database of stationary and rotating cascade performance is first obtained by quasi three-dimensional CFD simulations and used to train neural networks for the prediction of cascade performance under generalized conditions. Then the model directly calculates the operating point of a compressor having known geometry characteristics, including variable inlet guide/stator vane effects, as a function of mass flow rate and rotational speed. The model can also be used as a valuable preliminary design tool, obtaining geometry characteristics by imposing flow patterns.
|
|
| 60. |
- Benini, Ernesto, et al.
(författare)
-
Development of high-performance airfoils for axial flow compressors using evolutionary computation
- 2002
-
Ingår i: Journal of Propulsion and Power. - : American Institute of Aeronautics and Astronautics (AIAA). - 0748-4658 .- 1533-3876. ; 18:3, s. 544-554
-
Tidskriftsartikel (refereegranskat)abstract
- An original multiobjective optimization method is used to support the generation of a new family of profiles for two-dimensional cascades suitable for subsonic compressors. The aim of the optimization is to maximize the pressure ratio and to minimize the profile losses of a cascade, while conforming to a functional constraint on the operating range. The method uses an evolutionary algorithm featuring a novel evaluation technique conceived for multiobjective problems and a blade-to-blade inviscid/viscous solver for calculating flow quantities. As an example, an excerpt of optimized profiles is presented, and their performances are compared with those of conventional NACA 65 profiles. The new profiles show superior design performances both in efficiency and pressure rise, as well as a tolerance to incidence angles comparable to conventional profiles. The reasons of this improvement are discussed in detail on the basis of rigorous loss analysis.
|
|
