| 31. |
- Karimipanah, Taghi, 1953-
(författare)
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Deflection of wall-jets in ventilated enclosures described by pressure distribution
- 1998
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Ingår i: Building and Environment. - 0360-1323 .- 1873-684X. ; 34:3, s. 329-333
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Tidskriftsartikel (refereegranskat)abstract
- The pressure field in fluid systems reflects the flow configuration. Measurements of the pressure along the perimeter of a slot ventilated room have been conducted for different room sizes. The momentum of the jet at the end of the room is decreased with increasing room length. The impingement region (region where the influence of the opposing wall is present) starts, independent of room size, when the distance from the supply device is about 70% of the room length. Corner flows could not be predicted by CFD using the linear eddy viscosity or standard stress models. However, these effects may be captured by using a second moment closure turbulence model with a new near wall approach now available in literature.
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| 32. |
- Karimipanah, Taghi, 1953-, et al.
(författare)
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Investigation of air quality, comfort parameters and effectiveness for two floor-level air supply systems in classrooms
- 2007
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Ingår i: Building and Environment. - : Elsevier BV. - 0360-1323 .- 1873-684X. ; 42:2, s. 647-655
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Tidskriftsartikel (refereegranskat)abstract
- The method of distributing the outdoor air in classrooms has a major impact on indoor air quality and thermal comfort of pupils. In a previous study, ([11] Karimipanah T, Sandberg M, Awbi HB. A comparative study of different air distribution systems in a classroom. In: Proceedings of Roomvent 2000, vol. II, Reading, UK, 2000. p. 1013-18; [13] Karimipanah T, Sandberg M, Awbi HB, Blomqvist C. Effectiveness of confluent jets ventilation system for classrooms. In: Idoor Air 2005, Beijing, China, 2005 (to be presented).) presented results for four and two types of air distribution systems tested in a purpose built classroom with simulated occupancy as well as computational fluid dynamics (CFD) modelling. In this paper, the same experimental setup has been used to investigate the indoor environment in the classroom using confluent jet ventilation, see also ([12] Cho YJ, Awbi HB, Karimipanah T. The characteristics of wall confluent jets for ventilated enclosures. In: Proceedings of Roomvent 2004, Coimbra, Portugal, 2004.) Measurements of air speed, air temperature and tracer gas concentrations have been carried out for different thermal conditions. In addition, 56 cases of CFD simulations have been carried to provide additional information on the indoor air quality and comfort conditions throughout the classroom, such as ventilation effectiveness, air exchange effectiveness, effect of flow rate, effect of radiation, effect of supply temperature, etc., and these are compared with measured data.
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| 33. |
- Karimipanah, Taghi, 1953-, et al.
(författare)
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Theoretical and experimental investigation of impinging jet ventilation and comparison with wall displacement ventilation
- 2002
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Ingår i: Building and Environment. - 0360-1323 .- 1873-684X. ; 37:12, s. 1329-1342
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Tidskriftsartikel (refereegranskat)abstract
- This paper focuses on evaluating the performance of a new impinging jet ventilation system and compares its performance with a wall displacement ventilation system. Experimental data for an impinging jet in a room are presented and non-dimensional expressions for the decay of maximum velocity over the floor are derived. In addition, the ventilation efficiency, local mean age of air and other characteristic parameters were experimentally and numerically obtained for a mock-up classroom ventilated with the two systems. The internal heat loads from 25 person-simulators and lighting were used in the measurements and simulations to provide a severe test for the two types of ventilation systems. In addition to a large number of experimental data CFD simulations were used to study certain parameters in more detail. The results presented here are part of a larger research programme to develop alternative and efficient systems for room ventilation.
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| 34. |
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| 35. |
- Knutsson, Helena, 1953-, et al.
(författare)
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From flint to quartz : Organization of lithic technology in relation to raw material availability during the pioneer process of Scandinavia
- 2016
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Ingår i: Quaternary International. - : Elsevier. - 1040-6182 .- 1873-4553. ; 424, s. 32-57
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Tidskriftsartikel (refereegranskat)abstract
- Formal technologies and intensified reduction are often seen as responces to increased mobility and low abundance of lithic raw material of good flakeability and controllability. In this paper we discuss an alternative explanation to this hypothesis using the change in tool raw material experienced by flint using pioneers as they had to go from a formal blade technology to a simple flake technology as they settled in Scandinavia. The region is dominated by quartz and we used use-wear data as a means to evaluate the role of this type of raw material compared to the use profile of flint assemblages in the home territories of the pioneers. Although the technology changed through simplification and loss of formal production rules due to the low workability of quartz, we conclude that changes in the foraging range into areas of bad quality tool raw materials, does not need formalization of the technology. The quartz in our sample was used for a wide variety of activities in every aspect comparable to the range of uses identified in the contemporaneous blade assemblages based on flint. Instead of formalization of the lithic technology to cope with bad quality raw materials, it was diversified and simplified but without interfering with the organisational dimensions and design criteria of the bone technology.
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| 36. |
- Larsson, Ingbeth, 1953-, et al.
(författare)
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Teachers’ and parents’ reports on 3- to 6-year-old children’s sexual behavior : a comparison
- 2002
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Ingår i: International Journal of Child Abuse & Neglect. - 0145-2134 .- 1873-7757. ; 26:3, s. 247-266
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: The main purpose of the study was to compare observed range and frequency of sexual behavior in 3- to 6-year-olds in two different environments: the home and the daycare center. The study also aimed to investigate parental and staff opinions on child sexual behavior.Methods: Parents and daycare teachers of 185 preschool children, from different socio-economic housing areas, answered extensive questionnaires about each child’s sexual and general behavior. They were also asked about their own opinions on child sexual behavior.Results: Parents observed significantly more sexual behavior in their children at home compared to teachers’ observations at the daycare centers in all age groups, while teachers reported more general behavior problems. Significant gender differences on sexual behavior were displayed at the daycare centers but not at home. Rare behaviors at home were also very unusual at the daycare center. Parental and staff attitudes toward child sexuality were quite open, although 67% of the parents and 41% of the teachers never spoke to the children on sexual matters. One fifth of the adults used no term for genitals at all, and even fewer had a name for girls’ genitals.Conclusions: The findings indicate that young children explore their sexuality more at home than in settings with groups of children where the daily activities may be more structured and monitored. It enhances the importance of looking at the context in which the sexual behavior is taking place when investigating problematic sexual behavior.
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| 37. |
- Martin, Lene, 1953-
(författare)
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Computerized method to measure glare and contrast sensitivity in cataract patients
- 1999
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Ingår i: Journal of cataract and refractive surgery. - 0886-3350 .- 1873-4502. ; 25:3, s. 411-415
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To evaluate computerized methods for measuring glare sensitivity and visual acuity at 3 contrast levels in cataract patients. Setting: St. Erik's Eye Hospital, Stockholm, Sweden. Methods: In a prospective study, 25 consecutive cataract patients meeting the inclusion criteria were examined before and 12 weeks after cataract surgery. Measured were glare sensitivity and visual acuity at 3 contrast levels using the Ophthimus Y-VA Contrast Sensitivity lest and Glare Test. Results: Preoperatively, ail patients had impaired values compared with those in a group of age-matched normal volunteers (control group). Postoperatively, median values were similar to those in the age-matched control group in all parameters except glare sensitivity, which was significantly higher in the pseudophakic group (P = .03). Correlation coefficients between preoperative visual acuity and contrast sensitivity at 90%, 25%, and 10% were 0.50 (P = .01), 0.53 (P = .006), and 0.45 (P = .02), respectively, and between preoperative visual acuity and preoperative glare difference, 0.45 (P = .02). A significant correlation was found between age and visual acuity in the control group at all contrast levels: 90% (r = 0.61, P = .0018 ), 25% (r = 0.52, P = .01), and 10% (r = 0.42, P = .04). Median differences between Y-VA examinations (repeatability) were 0 LogMAR except between examinations 1 and 2 at the 25% contrast level, where it was 0.3 LogMAR. Conclusion: The Ophthimus Y-VA Test and Glare Test were useful in the preoperative evaluation of patients with cataract and mild to moderate visual impairment.
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| 38. |
- Micheletti, Michele, 1953-
(författare)
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The Swedish Election of 1988
- 1989
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Ingår i: Electoral Studies. - 0261-3794 .- 1873-6890. ; :8, s. 169-174
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 39. |
- Niklasson, Gunnar, 1953-, et al.
(författare)
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Electrochromic and Thermochromic Oxide Materials
- 2019
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Ingår i: Applied Surface Science. - : Elsevier BV. - 0169-4332 .- 1873-5584. ; 482, s. 70-72
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 40. |
- Nordström, Jan, 1953-, et al.
(författare)
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A stable and conservative nonlinear interface coupling for the incompressible Euler equations
- 2022
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Ingår i: Applied Mathematics Letters. - : Elsevier. - 0893-9659 .- 1873-5452. ; 132
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Tidskriftsartikel (refereegranskat)abstract
- Energy stable and conservative nonlinear weakly imposed interface conditions for the incompressible Euler equations are derived in the continuous setting. By discretely mimicking the continuous analysis using summation-by-parts operators, we prove that the numerical scheme is stable and conservative. The theoretical findings are verified by numerical experiments.
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