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- Arvidson, Magnus, et al.
(author)
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FIRESAFE II Alternative fixed‑fire extinguishing systems for ro-ro spaces on ships
- 2018
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Reports (other academic/artistic)abstract
- The effectiveness of ‘drencher systems’ per Resolution A.123(V) has been questioned for many years. This report presents a review of potential commercially available alternative systems and their expected performance efficiency, water consumption and estimated installation costs. Additionally, large‑scale fire tests were performed for selected systems.Three main alternative fire-extinguishing systems were identified:Compressed Air Foam Systems (CAFS)Foam-water sprinkler and foam‑water spray systems; andWater curtains.Water curtains was the least expensive system, but the areas sub‑divided by the water curtains require cargo spacing, resulting in significant yearly losses in income for a ship owner. Furthermore, water curtains were de-selected since they cannot replace a conventional fire-extinguishing system.The installation cost for the selected CAFS was very high and it gave limited fire suppression in the large‑scale fire tests, probably due to the limited discharge density of 2.4 mm/min.The system per MSC.1/Circ.1430 (10 mm/min) had superior performance while the system per Resolution A.123(V) (5 mm/min) and the foam‑water spray system (6.5 mm/min + foam) limited the fire size to some degrees. However, for a potential spill fire scenario, improvements of foam could be relevant.Foam injection could be an alternative, but no new system was recommended to be required.
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| 6. |
- Gustafsson, Erik, et al.
(author)
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Mathematical modelling of the regulation of spa (protein A) transcription in Staphylococcus aureus.
- 2009
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In: International journal of medical microbiology : IJMM. - : Elsevier BV. - 1618-0607 .- 1438-4221. ; 299:1, s. 65-74
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Journal article (peer-reviewed)abstract
- In the present work a general systems biology approach has been used to study the complex regulatory network controlling the transcription of the spa gene, encoding protein A, a major surface protein and an important virulence factor of Staphylococcus aureus. A valid mathematical model could be formulated using parameter values, which were fitted to quantitative Northern blot data from various S. aureus regulatory mutants using a gradient search method. The model could correctly predict spa expression levels in 4 different regulatory mutants not included in the parameter value search, and in 2 other S. aureus strains, SH1000 and UAMS-1. The mathematical model revealed that sarA and sarS seem to balance each other in a way that when the activating impact of sarS is small, e.g. in the wild-type, the repressive impact of sarA is small, while in an agr-deficient background, when the impact of sarS is maximal, the repressive impact of sarA is close to its maximum. Furthermore, the model revealed that Rot and SarS act synergistically to stimulate spa expression, something that was not obvious from experimental data. We believe that this mathematical model can be used to evaluate the significance of other putative interactions in the regulatory network governing spa transcription.
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- Idris, Shaza Bushra, et al.
(author)
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Polyester copolymer scaffolds enhance expression of bone markers in osteoblast-like cells
- 2010
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In: J BIOMED MATER RES PART A. - : Wiley. - 1549-3296. ; 94A:2, s. 631-639
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Journal article (peer-reviewed)abstract
- In tissue engineering, the resorbable aliphatic polyester poly(L-lactide) (PLLA) is used as scaffolds in bone regeneration. Copolymers of poly(L-lactide)-co-(epsilon-caprolactone) [poly(LLA-co-CL)] and poly(L-lactide)-co-(1,5-dioxepan-2-one) [poly(LLA-co-DXO)], with superior mechanical properties to PLLA, have been developed to be used as scaffolds, but the influence on the osteogenic potential is unclear. This in vitro study of test scaffolds of poly(LLA-co-CL) and poly(LLA-co-DXO) using PLLA scaffolds as a control demonstrates the attachment and proliferation of human osteoblast-like cells (HOB) as measured by SEM and a methylthiazol tetrazolium (MTT) colorimetric assay, and the progression of HOB osteogenesis for up to 3 weeks; expressed as synthesis of the osteoblast differentiation markers: collagen type 1 (Col 1), alkaline phosphatase, bone sialoprotein, osteocalcin (OC), osteopontin and runt related gene 2 (Runx2). Surface analysis disclosed excellent surface attachment, spread and penetration of the cells into the pores of the test scaffolds compared to the PLLA. MTT results indicated that test scaffolds enhanced the proliferation of HOBs. Cells grown on the test scaffolds demonstrated higher synthesis of Col 1 and OC and also increased bone markers mRNA expression. Compared to scaffolds of PLLA, the poly(LLA-co-CL) and poly(LLA-co-DXO) scaffolds enhanced attachment, proliferation, and expression of osteogenic markers by HOBs in vitro. Therefore, these scaffolds might be appropriate carriers for bone engineering. (C) 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 94A: 631-639, 2010
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- Ingason, Haukur, et al.
(author)
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Test Method and Performance of Fire Detection Systems in Tunnels
- 2016
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In: Proceedings from the 7th International Symposium on Tunnel Safety and Security. ; , s. 485-496
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Conference paper (other academic/artistic)abstract
- The results of a study carried out for the Swedish Transport Administration on fire detection in road tunnels is presented. Laboratory tests and numerous large-scale tests were carried out in order to verify a proposal for a test method for fire detection systems. The main aim was to investigate possible fire detector systems and to see if they could fulfil the requirement given by the Swedish Transport Administration to detect the fire within 90 seconds. The tests are presented as well as a recommendation for testing detection systems in Swedish road tunnels. In order to perform the fire test, pans of different sizes were tested in order to obtain a reasonable fire size. The method proposed requires the use of three 0.6 m diameter standard pans, each containing eight litres of 95 octane gasoline, and air flow velocities of 2 m/s and 6 m/s. It was found out that using only one 0.6 m pan is sufficient if early warning is required without identifying the position for the fire-fighting system.
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