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- Abdul Hamid, Akram, et al.
(författare)
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Evaluation of set points for moisture supply and volatile organic compounds as controlling parameters for demand controlled ventilation in multifamily houses
- 2014
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Konferensbidrag (refereegranskat)abstract
- The main purpose has been to evaluate existing set points (thresholds) and suggest proper set points, for the regulation of the air change rate in a demand controlled mechanical ventilation (DCV) system. The DCV is controlled by measurements in the supply and exhaust air of the vapor content and volatile organic compounds (VOCs) for each dwelling in multifamily houses. Results have been achieved through a literature review and laboratory tests. The threshold for the maximum ventilation rate (0.8 ac/h) should be set at 1000 ppm (CO2-eq.). Preferably, a minimum ventilation rate of 0.5 ac/h should be set with current thresholds (800-1000 ppm CO2-eq.). With a lower minimum ventilation rate (e.g. 0.1 ac/h) the lower threshold should be set at 450 ppm (CO2-eq). In order to deal with heavy moisture production the threshold for the moisture supply is suggested to be set at 3 g/m3.
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| 2. |
- Amanizadeh, Farhad, et al.
(författare)
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Starve fed emulsion copolymerization of vinyl acetate and 1-hexene at ambient pressure
- 2014
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Ingår i: Polymer international. - : Wiley. - 0959-8103 .- 1097-0126. ; 63:10, s. 1850-1855
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Tidskriftsartikel (refereegranskat)abstract
- A novel emulsion copolymer of vinyl acetate (VAc) and 1-hexene was synthesized at ambient pressure. The feeding technique, initiation system and reaction time of the copolymerization were optimized based on molecular characteristics such as the weight contribution of 1-hexene in the copolymer chains and glass transition temperature (T-g) as well as on bulk properties like minimum film-formation temperature (MFFT) and solid content. According to nuclear magnetic resonance spectroscopy and differential scanning calorimetry results, the combination of starve feeding and redox initiation, within a reaction time of 4h, effectively led to the copolymerization at ambient pressure between highly reactive polar VAc monomers and non-polar 1-hexene monomers of low reactivity. The copolymer showed a lower T-g and MFFT, and a reasonable solid content compared to the poly(vinyl acetate) (PVAc) homopolymer. The consumption rate, hydrolysis of acetate groups and chain transfer reactions during the polymerization were followed using infrared spectroscopy. Based on the results, the undesirable reactions between the VAc blocks were hindered by the neighbouring 1-hexene molecules. Tensile testing revealed an improvement in the toughness and elongation at break of VAc-1-hexene films compared to PVAc films.
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| 3. |
- Amirinejhad, S., et al.
(författare)
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Study of double oxide film defect behaviour in liquid Al-Mg alloys
- 2013
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Ingår i: International Journal of Cast Metals Research. - : Taylor & Francis. - 1364-0461 .- 1743-1336. ; 26:6, s. 330-338
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Tidskriftsartikel (refereegranskat)abstract
- The change in the composition of oxide layers and the possibility of the formation of bonding between the layers of a double oxide film defect when held in Al melts containing 0.7, 1 and 2 wt-%Mg were investigated. The defect was modelled by maintaining two aluminium oxide layers in contact with one another in the melt at 1023 K for times between 5 s and 50 h. Any changes in the composition and morphology of these layers were studied by SEM and energy dispersive X-ray. The results showed that in all the alloys, the initial Al2O3 layer first transformed to MgAl2O4 and then to MgO. These transformations caused the two layers to bond together gradually. The results confirmed that, in all the Al alloys containing 0.3-4.5 wt-%Mg, oxide films have the chance to heal if held in the liquid metal for a long enough period of time.
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| 4. |
- Doostmohammadi, Hamid, et al.
(författare)
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Inclusion Characteristics of Bearing Steel in a Runner after Ingot Casting
- 2010
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Ingår i: STEEL RES INT. - : Wiley. - 1611-3683 .- 1869-344X. ; 81:2, s. 142-149
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Tidskriftsartikel (refereegranskat)abstract
- In the uphill teaming method of ingot casting molten metal from the ladle goes into the runner system, which feeds one or several ingot moulds. This method is still important for production of bearing steel. In order to make clean steel, which has a controlled amount of inclusions, good understanding of inclusions characteristics is necessary In this work non-metallic inclusions of steel left in the runner part of an ingot casting system were studied. Inclusion type, size, and morphology were the main focus of this study A scanning electron microscope (SEM) was used to assess inclusion size and morphology The chemical composition of inclusions was determined by SEM equipped with EDS. An automated program called 'INCAFeature' was used to collect statistics of inclusion characteristics. Based on the statistical analysis of inclusion composition, four types of inclusions including oxides, sulfides, carbonitrides and complex inclusions were defined. The inclusion characteristics in the runner were also compared to literature data of inclusions found in ladle and mould samples.
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| 10. |
- Keller, Annika, et al.
(författare)
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Mutations in the gene encoding PDGF-B cause brain calcifications in humans and mice
- 2013
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 45:9, s. 1077-
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Tidskriftsartikel (refereegranskat)abstract
- Calcifications in the basal ganglia are a common incidental finding and are sometimes inherited as an autosomal dominant trait ( idiopathic basal ganglia calcification (IBGC)). Recently, mutations in the PDGFRB gene coding for the platelet-derived growth factor receptor beta (PDGF-R beta) were linked to IBGC. Here we identify six families of different ancestry with nonsense and missense mutations in the gene encoding PDGF-B, the main ligand for PDGF-R beta. We also show that mice carrying hypomorphic Pdgfb alleles develop brain calcifications that show age-related expansion. The occurrence of these calcium depositions depends on the loss of endothelial PDGF-B and correlates with the degree of pericyte and blood-brain barrier deficiency. Thus, our data present a clear link between Pdgfb mutations and brain calcifications in mice, as well as between PDGFB mutations and IBGC in humans.
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