| 11. |
- Hore, Samar Kumar, et al.
(författare)
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Detecting arsenic-related skin lesions : Experiences from a large community-based survey in Bangladesh
- 2007
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Ingår i: International Journal of Environmental Health Research. - : Informa UK Limited. - 0960-3123 .- 1369-1619. ; 17:2, s. 141-149
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Tidskriftsartikel (refereegranskat)abstract
- A cross-sectional survey was conducted in Matlab, Bangladesh, to determine the prevalence of skin lesions (a three-step procedure) associated with arsenic exposure and discuss validity and feasibility in relation to recommended screening algorithms. Cases with skin lesions were identified by screening above 4 years of age (n = 166,934). Trained field teams conducted a careful house-to-house screening and identified 1682 individuals with skin lesions, who were referred to physicians for confirmation. Physicians diagnosed 579 cases as probable and documented all these with digital photographs. Two experts inspected all photographs for consensus agreement that was reached for 504 cases. Using the experts' opinions as reference, the positive predictive value of the physicians' diagnosis was 87% (male = 82% vs. female = 94%; p < 0.01). The physicians had difficulties in separating arsenic-induced keratosis from differential diagnoses, while probability for correct diagnosis was high for arsenic-related pigmentation changes. Including information on current arsenic concentration in drinking water (which was masked at time of skin examination) or urine in the diagnostic algorithm should have increased the number of false negative cases. In the present transition of drinking water sources these markers of current exposure levels provide no information on past exposure. A 2 - 3 step procedure with house-to-house screening and clinic-based confirmation of arsenic-induced skin lesions is a feasible approach. Information on arsenic concentration in current water sources or in urine should not have improved the precision in the diagnosis. These results may have policy implications for community screening of arsenic-related skin lesions in Bangladesh and elsewhere.
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| 12. |
- Hosseinzadeh, N., et al.
(författare)
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A curriculum for electrical power engineering based on project based learning philosophy
- 2009
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Ingår i: Proceedings of the IEEE International Conference on Industrial Technology. - Churchill, VIC. - 9781424435067
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Konferensbidrag (refereegranskat)abstract
- A curriculum for electrical power engineering based on project based learning (PBL) methodology has been designed. Although the educational program is totally based on PBL, this curriculum is comprised of two types of study units. Some study units are based on a combination of lectures, tutorials and problem based learning techniques. Others are fully based on PBL. As an example of a fully PBL study unit, a course in power system analysis has been developed. For delivering the course in PBL, a power system laboratory has been established, which gives students access to professional software packages. Realworld industry-relevant projects are defined in the areas of power system operation and planning. These projects are used as stimuli for student learning. Portfolio assessment is used to assess students learning outcome. The first delivery of the course has been successful with positive feedback from students.
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| 13. |
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| 14. |
- Karimi, K., et al.
(författare)
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Conversion of rice straw to sugars by dilute-acid hydrolysis
- 2006
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Ingår i: Biomass and Bioenergy. - : Elsevier BV. - 0961-9534 .- 1873-2909. ; 30:3, s. 247-253
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Tidskriftsartikel (refereegranskat)abstract
- Hydrolysis of rice straw by dilute sulfuric acid at high temperature and pressure was investigated in one and two stages. The hydrolyses were carried out in a 10-l reactor, where the hydrolysis retention time (3-10 min), pressure (10-35 bar) and acid concentration (0-1%) were examined. Optimization of first stage hydrolysis is desirable to achieve the highest yield of the sugars from hemicellulose and also as a pretreatment for enzymatic hydrolysis. The results show the ability of first stage hydrolysis to depolymerize xylan to xylose with a maximum yield of 80.8% at hydrolysis pressure of 15 bar, 10 min retention time and 0.5% acid concentration. However, the yield of glucose from glucan was relatively low in first stage hydrolysis at a maximum of 25.8%. The solid residuals were subjected to further dilute-acid hydrolysis in this study. This second-stage hydrolysis without addition of the acid could not increase the yield of glucose from glucan beyond 26.6%. On the other hand, the best results of the hydrolysis were achieved, when 0.5% sulfuric acid was added prior to each stage in two-stage hydrolysis. The best results of the second stage of the hydrolysis were achieved at the hydrolysis pressure and the retention time of 30 bar and 3 min in the second stage hydrolysis, where a total of 78.9% of xylan and 46.6% of glucan were converted to xylose and glucose, respectively in the two stages. Formation of furfural and HMF were functions of the hydrolysis pressure, acid concentration, and retention time, whereas the concentration of acetic acid was almost constant at pressure of higher than 10 bar and a total retention time of 10 min.
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| 15. |
- Kiaei, Mohammad S., et al.
(författare)
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Efficient Fully Format Compliant Selective Scrambling Methods for Compressed Video Streams
- 2006
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Ingår i: Proceedings of the Advanced International Conference on Telecommunications and International Conference on Internet and Web Applications and Services, AICT/ICIW'06. - 9780769525228 ; , s. 42-
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Konferensbidrag (refereegranskat)abstract
- Format compliance, a desirable feature of multimedia security systems, means that the secured bitstream resembles the unprotected compressed bitstream. It is called full format compliance, if the scrambled stream can be decoded by a typical decoder. In this paper, we address the issues that are to be carefully taken into account to develop efficient fully format compliant scrambling methods for compressed video. We also propose new selective scrambling methods for securing compressed video streams. The security issues, in different parts of these scrambling methods, are analyzed and their impact on bit-rate and complexity is discussed. We show that our scrambling methods provide significantly higher security and full format compliance, while having less impact on bit-rate and encoding/decoding complexity, as compared to existing semi-format compliant scrambling methods. The proposed techniques are integrated into the baseline mode of H.263 low bit-rate video coding standard.
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| 16. |
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| 20. |
- Rasouli, S, et al.
(författare)
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Effect of Annular Fins on Heat Transfer of Horizontal Immersed Tube in Bubbling Fluidized Beds
- 2005
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Ingår i: Powder Technology. - : Elsevier. - 0032-5910 .- 1873-328X. ; 154:1, s. 9-13
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Tidskriftsartikel (refereegranskat)abstract
- Experiments were conducted in a bubbling air-fluidized bed to investigate the effect of annular fins of constant thickness on heat transfer. Steady state time averaged local heat transfer coefficient measurements were made by the local thermal simulation technique in a cold bubbling fluidized bed (90 mm ID, 260 mm tall) with horizontally immersed tube initially with no fin and then with three fixed annular fins of constant thickness. Silica sand of mean particle diameter 307 Am and 200 Am were used as the bed materials. The superficial velocity of air was from minimum fluidization conditions, umf, to approximately 3_umf. The results indicate that, although the heat transfer coefficient falls with the use of fins, the total heat transfer rises as a result of the greater surface area. Increasing the particle diameter reduces the heat transfer coefficient not only for unfinned horizontal tube but also for annular finned horizontal tube at the same conditions of fluidized bed. Based on the experimental data, correlations are proposed for predicting heat transfer coefficient from fluidized bed to horizontally immersed tubes with and without fins.
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